REL301/302 Firmware Version 1.23 (08/19/03) Addendum to Instruction book V1.20, F

Transcription

1 REL301/302 Firmware Version 1.23 (08/19/03) Addendum to Instruction book V1.20, F Revisions These revisions are to be added (inserted) to the REL301/302 Version 1.20 Instruction Book Revision History as page xvi Version 1.23 (08/19/03) 1. A change has been done to accommodate a newer generation of communication port switch device. This does not affect customer applications. 2. With this firmware revision the applicable RCP version is V2.07. Version 1.22 (07/20/01) 1 In situations of fault types as zone-1 as well as instantaneous overcurrent, only one LED lights. Now with modified logic, LED s corresponding to all the pickups will light. LCD display, records etc. will not be affected. 2. Instantaneous over-current tripping was not working according to the setting. This was because of an error in the associated timer and has been rectified. Version 1.21 (11/24/99) Corrected an error in the Blocking system. The Pilot will not trip with RX=0 if the system was first set to POTT/PUTT/3ZNP and RX1 or RX2 present and then if the system was changed to Blocking. General corrections in the Instruction Book V1.20, F: Page 5: Item 1.5.1: The configuration software RCP for REL301/302 is available at our web site select Transmission products, select REL301/302 and then configuration software. The waveforms generated by REL301/302 can be viewed by OSCAR or RELTools (RELWave), both of which are available for download along with the above. Page 8: Some time earlier, an auto reclose catalog version with 120V phase to neutral synch input was added. The sixth digit of the catalog will be with the letter P for this model. (Existing variations are N for no reclosing, R for autoreclose without synch check, S for reclosing + synchrocheck, 70V phase to neutral T for reclosing + synchrocheck, 120V phase to phase) Page 97: Changes in autoreclose firmware, V1.27 has necessitated some changes in the overall scheme drawing. Please refer to note 4 to 6 of the drawing.

2

3

4 ABB Automation, Inc. Substation Automation & Protection Division Coral Springs, FL Allentown, PA Instruction Leaflet F Effective: July, 1998 Supersedes IL E dated January, 1998 REL 301/302 Version 1.20 Numerical Distance Relay ABB Network Partner

5 REL 301/302 Protection (V 1.20)

6 REL301/302 REVISION NOTICE DATE REV LEVEL PAGES REMOVED PAGES INSERTED 5/95 B V1.11 3/96 C V , , 3-9 (Replaced) 12/97 D V1.12 Section 1-6, 7, 8, 9 Section 1-6, 7, 8, 9 Section 2-15, 24, 29, 30, Section 2-15, 24, 29, 30, 40, 45, 47, 48, 49, 53 40, 45, 47, 48, 49, 53 Section 3-56, 57, 58, 59, Section 3-56, 57, 58, 59, 64, 65, 68, 71 64, 65, 68, 71 Section 4-85, 87, 91, 92, Section 4-85, 87, 91, 92, 93, 95, 105, , 95, 105, 106 Section 5-111, 115, 116, Section 5-111, 115, 116, /98 E V1.20 Introduction - xv Section 2-22, 25, 33, Section 2-22, 25, 33, Section 4-91, 92, 94, Section 4-91, 92, 94, /98 F V1.20 Section 2-21, 25, 33, 35 Section 2-21, 25, 33, 35 Section 4-89, 90, 106 Section 4-89, 90, 106 CHANGE SUMMARY: A CHANGE BAR ( ) LOCATED IN THE MARGIN INDICATES A CHANGE TO THE TECHNICAL CONTENT

7 I.L ! CAUTION It is recommended that the user of REL301/302 equipment become acquainted with the information in this instruction leaflet before energizing the system. Failure to do so may result in injury to personnel or damage to the equipment, and may affect the equipment warranty. If the REL301/302 relay system is mounted in a cabinet, the cabinet must be bolted to the floor, or otherwise secured before REL301/302 installation, to prevent the system from tipping over. All integrated circuits used on the modules are sensitive to and can be damaged by the discharge of static electricity. Electrostatic discharge precautions should be observed when handling modules or individual components. ABB does not assume liability arising out of the application or use of any product or circuit described herein. ABB reserves the right to make changes to any products herein to improve reliability, function or design. Specifications and information herein are subject to change without notice. All possible contingencies which may arise during installation, operation, or maintenance, and all details and variations of this equipment do not purport to be covered by these instructions. If further information is desired by purchaser regarding a particular installation, operation or maintenance of equipment, the local ABB representative should be contacted. Trademarks All terms mentioned in this book that are known to be trademarks or service marks are listed below. In addition, terms suspected of being trademarks or service marks have been appropriately capitalized. ABB Power T&D Company Inc. cannot attest to the accuracy of this information. Use of a term in this book should not be regarded as affecting the validity of any trademark or service mark. IBM and PC are registered trademarks of the International Business Machines Corporation WRELCOM is the registered trademark of the ABB Power T&D Company Inc. INCOM is the registered trademark of the Westinghouse Electric Corporation Copyright ASEA BROWN BOVERI, ABB Power T&D Company Inc. 1993, 1994, 1995, 1996, 1997, 1998 This document contains information that is protected by copyright. All rights are reserved. Reproduction, adaptation, or translation without prior written permission is prohibited, except as allowed under the copyright laws. ABB does not convey any license under its patent rights nor the rights of others. iv

8 I.L PREFACE Scope This manual describes the functions and features of the REL301(Non-pilot Relay System) and REL302 (Pilot Relay System). It is intended primarily for use by engineers and technicians involved in the installation, testing, operation and maintenance of the REL301/302 system. Equipment Identification The REL301/302 equipment is identified by the Catalog Number on the REL301/302 chassis nameplate. The Catalog Number can be decoded by using Catalog Number Table in Section Both REL301 and REL302 can be either vertically or horizontally mounted. Production Changes When engineering and production changes are made to the REL301/302 equipment, a revision notation (SUB #) is reflected on the appropriate schematic diagram, and associated parts information. Equipment Repair Repair work is done most satisfactorily at the factory. When returning equipment, contact your field sales representative for RMR authorization. All equipment should be returned in the original packing containers if possible. Any damage due to improperly packed items will be charged to the customer. Document Overview Section 1 provides the Product Description. Section 2 presents the Functional Specification. Section 3 presents the Setting Calculations. Installation and Operation are described in Section 4. Finally, Section 5 covers Acceptance Test, Maintenance Test and Calibration procedures. Contents of Relay System The REL301/302 Relay System includes the style numbers, listed below, for each module. Module Style Number FT-10 Surge Protection B35 Backplane Surge Protection C53 Option (Reclosing/synch-check) C77 Filter (Input Module) C34 Microprocessor C55 Display (Optional) C69 Power Supply/Relay Outputs C68 VT C80 CT C79 v

9 INSTRUCTION MANUAL REL 301/302 TABLE OF CONTENTS SECTION PAGE SECTION 1: PRODUCT DESCRIPTION INTRODUCTION REL301/302 FEATURES Standard Features for REL301 (Non-Pilot) Standard Features for REL302 (Pilot) Optional Features for the Non-Pilot REL301 and Pilot REL REL301/302 CONSTRUCTION REL301/302 Outer Chassis REL301/302 Inner Chassis UNIQUE FEATURES Fault Detection Software Fault Mode and Restricted Fault Tests Unique Characteristics of REL301/ Self-checking Software UNIQUE REMOTE COMMUNICATION PROGRAM (RCP) ABB Bulletin Board SPECIFICATIONS Technical External Connections Contact Rating Data Chassis Dimensions And Weight Environmental and Type Test Data REL301/302 Catalog Numbers SECTION 2: FUNCTIONAL DESCRIPTION 2. 1 INTRODUCTION LINE MEASUREMENT TECHNIQUES Single-Phase-to-Ground Fault Three-Phase Fault Phase-to-Phase Fault MEASUREMENT ZONES Zone-1 Trip vi

10 I.L SECTION PAGE Zone-2 Trip Zone-3 Trip Zone-1 Extension NON-PILOT OPERATION Zone Distance Phase and Ground Relay with Reversible Zone-3 Phase and Ground Inverse Time Overcurrent Ground Backup Loss of Potential Supervision Loss of Current Supervision (LOI) Fault Detector Overcurrent Supervision Highset Overcurrent Trip Close-Into-Fault Trip (CIFT) Unequal-Pole-Closing-Load Pickup Logic Loss-of-Load Accelerated Trip Logic Current or Voltage Change Fault Detector (DI, DV) Phase Directional Polarization Ground Directional Polarization Selection Instantaneous Forward Directional Overcurrent (FDOG) Instantaneous Reverse Directional Overcurrent Ground (RDOG) Programmable Reclose Initiation and Reclose Block Logic Output Contact Test Out-of-Step Block Logic Fault and Oscillographic Data Fault Data Oscillographic Data REL302 PILOT SYSTEM Pilot System Type Permissive Overreach Transfer Trip/Simplified Unblocking Permissive Underreach Transfer Trip Directional Comparison Blocking Pilot Ground Overcurrent High Resistance Ground Fault Supplement Instantaneous Reverse Directional Overcurrent Ground Supplement to Carrier Ground Start, Blocking Scheme Pilot Ground Start, POTT terminal Line Application Weakfeed Trip Application Weakfeed System Application Reclose Block on Breaker Failure Squelch vii

11 INSTRUCTION MANUAL REL 301/302 SECTION PAGE 2. 6 PROGRAMMABLE CONTACT OUTPUTS SECTION 3: SETTINGS CALCULATIONS 3.1. MEASUREMENT UNITS AND SETTING RANGES CALCULATION OF REL301/302 SETTINGS Ratio of Zero and Positive Sequence Impedances (ZR) Zone-1 Distance Settings Zone-2 Distance Settings Zone-3 Distance Settings Overcurrent Settings Out-of-Step Block (OS Block) Blinder Settings (OS Inner and OS Outer) Timer Settings (Definite Time Setting) Timer Settings (Torque Control Overcurrent) REQUIRED SETTINGS APPLICATION Oscillographic Data (OSC Data) Capture Setting Fault Data (Flt. Data) Capture Setting Current Transformer Ratio Setting (CT Ratio) Voltage Transformer Ratio Setting (VT Ratio) Frequency Setting (Freq.) Current Transformer Type Setting (CT Type) Read Primary Setting (Read Out) Ohms Per Unit Distance (X / Dist) Distance Type (DistUnit) Setting Reclosing Mode (RI Type) Setting Reclose Initiation Settings Remote Breaker Failure, Reclose Block (RemBF RB) Remote Pilot Control (Pilot) Setting System Type Selection (SystType) For The Pilot REL302 Only Distance/Overcurrent Step Distance Timers Zone-3 Direction Setting (Zone-3) Positive Sequence Impedance Line Angle (Ang Pos.)* Zero Sequence Impedance Angle (Ang Zero)* Zero Sequence/Positive Sequence Ratio (ZOL/Z1L)* Low Voltage Settings (Low V) Polarizing Settings Overcurrent Ground Backup Close-Into-Fault Trip Setting (CIF Trip) viii

12 I.L SECTION PAGE Load Loss Trip Setting (LL Trip) Loss of Potential Block Setting (LOP Blk) Loss of Current Block Setting (LOI Blk) Trip Alarm Setting (Trip Alm) Remote Setting (Rem. Set) Real-Time Clock Setting RECLOSE INITIATION MODE PROGRAMMING For Non-pilot and Pilot Systems SECTION 4: INSTALLATION AND OPERATION SEPARATING THE INNER AND OUTER-CHASSIS TEST PLUGS AND FT SWITCHES EXTERNAL WIRING FRONT PANEL MAN-MACHINE INTERFACE (MMI) LED Indicators LEDs and Display Reset Display Module Front Panel Operation JUMPER CONTROLS COMMUNICATION PORT(S) USE Introduction Communication Port Options Personal Computer Requirements Connecting Cables Relay Password and Setting Change Protection FRONT RS-232C COMMUNICATIONS PORT Communications Port Set Up Operations Troubleshooting SIXTEEN FAULT TARGET DATA OSCILLOGRAPHIC DATA PROGRAMMABLE CONTACT OUTPUTS (Optional Feature) Programmable Contact Outputs Applications Breaker Failure Protection ix

13 INSTRUCTION MANUAL REL 301/302 SECTION PAGE SECTION 5: REL301/302 ACCEPTANCE TEST AND MAINTENANCE PROCEDURES NON-PILOT ACCEPTANCE TESTS FOR REL301/ Front Panel Man-Machine-Interface (MMI) Test Input quantities Verification and Metering Display Test Mode Zone-1 Impedance Accuracy Check Input Opto-Coupler Check (Also see Step 12) Input Transformer (Ip) Check Output Contact and Input Circuit Verification Test PILOT ACCEPTANCE TESTS (FOR REL302 ONLY) Non-Pilot Acceptance Tests for REL301/ Input Opto-Coupler Check MAINTENANCE PROCEDURES Periodic Maintenance Tests Using Remote or Local Data Communication Using Man-Machine Interface Routine Visual Inspection Perform the Acceptance Test CALIBRATION Pre-Calibration A/D Calibration Real-Time Clock Calibration on Microprocessor Module x

14 I.L LIST OF FIGURES Section Number Page Number Section 1 REL 301/302 Layout. (Vertical) REL 301/302 Layout. (Horizontal) REL 301/302 Outer Chassis REL 301 Inner Chassis (Same as REL302) REL 301/302 Relay Program Functions Section 2 REL301/302 Characteristics/R-X Diagram Mho Characteristic for Phase-to-Ground Faults Mho Characteristics for Three-Phase Faults (No Load Flow) Mho Characteristics for Phase-to-Phase and Two Phase-to-Ground Faults (No Load Flow) Logic Drawing Symbols Zone-1 Trip Logic Zone-2 Trip Logic Zone-3 Trip Logic Zone-1 Extension Scheme Inverse Time Overcurrent Ground Backup Logic Loss-of-Potential Logic Loss-of-Potential Logic (System Diagram) Loss of Current Monitoring Logic Overcurrent Supervision Instantaneous Overcurrent Highset Trip Logic REL301/302 Close-Into-Fault Trip (CIFT) Logic Special Application for CIF Logic with Time Delay Pickup Unequal-Pole-Closing/Load Pickup Trip Logic & Reverse Block (TBM) Logic Load Loss Accelerated Trip Logic Reclosing Initiation Logic Out-of-Step Block Logic (Blinder Characteristics) Out-of-Step Block Logic REL302 POTT/Unblocking, PUTT and Blocking Pilot Relay REL302 POTT/Unblocking and PUTT Pilot Trip Logic REL302 Channel Sending/Receiving Logic in POTT/Unblocking Schemes REL302 Channel Sending /Receiving Logic in PUTT Scheme REL302 Blocking System Logic Power Reversal on POTT/Unblocking Schemes Unequal Pole Closing on Fault REL302 Pilot Ground Trip Supplemented by FDOG REL302 Additional Logic for POTT/Unblocking Schemes on 3-Terminal Line Application xi

15 INSTRUCTION MANUAL REL 301/302 SECTION NUMBER PAGE NUMBER REL302 Additional Logic for PUTT Scheme on 3-Terminal Line Application REL302 Weakfeed Application REL302 Reversible Zone-3 Phase and Ground (Reverse Block Logic) Section 3 % Overreach Resulting from dc Offset Effect CO-2 Curve Characteristics CO-5 Curve Characteristics CO-6 Curve Characteristics CO-7 Curve Characteristics CO-8 Curve Characteristics CO-9 Curve Characteristics CO-11 Curve Characteristics Overcurrent Reset Characteristics Section 4 REL 301/302 Terminals REL 301/302 Systems External Connection REL 301/302 Systems External Connection REL 301/302 Breaker Failure DC Schematic Section 5 Filter (Input) Module Power Supply/Output Module Microprocessor Module Test Connections For: Test Connection for AØ - Ground Test Test Connection for BØ-Ground Test Test Connection for CØ-Ground Test Test Connection for AØ-Ground Test (Dual Polarizing) xii

16 I.L TABLES SECTION NUMBER PAGE NUMBER Section 2 PHASE AND GROUND SETTINGS (5 tables) Section 3 TRIP TIME CONSTANTS FOR CURVES RECLOSING INITIATION MODE PROGRAMMING CURRENT TRANSFORMER SETTINGS Section 4 SETTING DISPLAY METERING DISPLAY TARGET (FAULT DATA) DISPLAY (2 PAGES) PROGRAMMABLE CONTACT OUTPUTS COMMUNICATIONS CABLE REQUIREMENTS DIP SWITCH SETTING CHART RS-PONI (9-PIN) COMMUNICATIONS SPEED SETTING Section 5 FILTER MODULE JUMPER SETTINGS POWER SUPPLY MODULE JUMPER SETTINGS MICROPROCESSOR MODULE JUMPER SETTINGS REL 301 SETTINGS (NON-PILOT SYSTEM) REL 302 SETTINGS (PILOT SYSTEM) REL 301/302 REFERENCE DRAWINGS xiii

17 INSTRUCTION MANUAL REL 301/302 REL301 and 302 Version 1.12 FEATURES ADDED AND IMPROVEMENTS MADE TO VERSION REL301 and REL Changed 3Vo sensitivity from 3 volts to 1 volt for the directional units in order to increase the sensitivity for zone-2 and zone Changed the loss of current blocking ( LOI Blk ) timer from 0.5/0.5 to 10/0.5 seconds in order to prevent blocking of zone-2 ground distance, zone-3 ground distance for settings of T2G and/or T3G are greater than 0.5 seconds and ground backup tripping longer than 0.5 seconds. 1.3 Improved the loss of potential blocking logic by removing the lead between LOP Timer (8/ 0) output and AND1G. 1.4 Corrected the angle display for the 1-amp ct application. Now, the angle display is extendedfrom 50% to 10% of the ct rating. 1.5 Extended the front communication access time from 2 to 15 minutes after depressing the front pushbutton. 1.6 Redefined the programmable contact output signals LLT & TBM to IM & IOM, respectively. 1.7 Corrected a software error for the operation of the programmable output contact OC Corrected the LV setting for the use of the programmable output contacts. The output contacts of LV should be picked up if any one of the voltages fall below the LV setting. In version 1.11, the normally open contacts closed if any one of the voltages exceeded the LV setting. 1.9 Improved the accuracy of the programmable contact outputs (PCO) pickup and dropout timers Improved the accuracy of 3-phase distance tripping by removing KI0 compensation which was incorrectly applied to this calculation Corrected LED and Man-Machine Interface targeting mismatch. LED could indicate incorrect fault type for certain trip operations. 2.1 Changed the RDOG timer from 16/0 to 33/0 ms. For a 3-phase fault at 0% location, the RDOGmay pick up momentarily and may start the TBM (carrier keying); therefore, it may delay the pilot trip action. NOTE: For the pilot application, the setting of FDGT should be greater than 3 cycles. 2.2 Removed reclose initiate output from weakfeed trip logic. xiv

18 I.L SIGNIFICANT CHANGES TO VERSION 1.20 (FROM V1.12) 1. For the setting of Dir Type=Dual Polariz, use current polarizing (3I 0 & I P ) for the forward directional calculation (FDOG) when the current I P is greater than 1.0 amp. Use voltage polarizing (3V 0 & 3I 0 ) as backup for the forward direction calculation when the input current I P is less than 1.0 amp. 2. For the settings of LOP Blk=Yes and Dir Type=Dual Polariz, maintain the directionality of Inst. G and ground backup GB Dir. (if GB Dir.=Yes) for I P greater than 1.0 amp. Use current polarization of Inst. G and GB Dir during loss of potential condition. 3. Change loss of potential (LOP) logic by adding 0/16 timer between AND223 and OR221. For time delay trip units (zone-2, zone-3, etc.) in V1.12, the LOP logic may block the trip on a 3-phase fault if all fault voltages (Va, Vb and Vc) are less than 7 volts. 4. Add an inverted input form LOP (0/500 timer) to supervise the AND220. This provides blocking of the distance units for 500 ms after the LOP Block condition is removed. 5. Compensate the time/angle shift due to a long time delay setting (T2 or T3). Accumulated angle measurement error may cause the forward directional to reset during a sustained fault. 6. Added a transient block timer of 2 cycles in instantaneous ground trip logic to prevent a trip for a forward direction fault occurring immediately after a reverse direction fault. 7. Change the software routine for trip seal-in (TRSL). Any time a high speed trip (HST) occurs, set TRSL. For some cases in V1.12, HST tripped the relay then dropped out before the TRSL set; therefore, the targets were not recorded. 8. For blocking systems only, REL 302 only: Improved channel receive logic security by adding a dropout delay of 8 ms for both reciever 1 input (RX1) and reciever 2 input (RX2) which is asserted after RX1 or RX2 has been received longer than 3 cycles. This logic change overcomes the problem momentary loss of signal due to the external fault clearing noise. 9. Generate a new signal for programmable contact output logic, 3V0T=(Va+Vb+Vc) which equals logic 1 if 3V0T is greater than 105 Vrms. 10. Replace 21Bl and FDOG, with 3V0T and 52a respectively, in the Programmable Contact Output logic table. 11. Change the incremental steps of programmable contact output timers from 10 milliseconds to 1 cycle and change the settable range from 0-5 seconds to cycles. xv

19 Section 1. PRODUCT SPECIFICATION INTRODUCTION The REL 301 and REL 302 relays are numerical transmission line protection systems, with three zones (four zones in REL 302) of distance protection. All measurements and logic are performed by an Intel 80C196 microcontroller. Self-checking line voltage and current monitoring is included REL 301/302 FEATURES Standard Features for REL 301 (Non-Pilot) 100% Numerical processing 3-Zone step distance phase and ground relay, with reversible Zone-3 phase and ground; 4 impedance units per zone: 3 phase-to-ground; 1 phase-to-phase. T1 timer (0 to 15 cycles) Independent timers for phase and ground step distance applications Overcurrent supervision of phase and ground distance Selectable Zone-2 torque controlled phase and/or ground overcurrent Inverse time directional or non-directional (selectable) overcurrent ground backup logic Loss of potential supervision Loss of current supervision Instantaneous forward directional phase and ground high set overcurrent trip Close Into Fault Trip Unequal-pole-closing load pickup logic Selectable Loss-of-Load accelerated trip logic Selectable Zone-1 extension Current change fault detector (DI) Voltage change fault detector (DV) Breaker trip circuit test Push-to-close test for output contacts Binary input test of contact input circuits Software switches for functional tests, e.g., (Carrier Send and Carrier Receivers) Selectable polarizing for directional overcurrent ground units (zero sequence, negative sequence and dual Programmable Reclose initiation and reclose block outputs Fault location capability Self-checking software Trip contact sealed in by trip current, and selectable dropout delay of 0 or 50 ms 16 fault records with setting selectable data capture choices which trigger fault recording Real-time clock (Can be externally set with optional IRIG-B interface) Low voltage pickup setting for close into fault trip logic Setting positive sequence to zero sequence ratio Double blinder logic for out of step blocking 1

20 INSTRUCTION MANUAL REL 301/302 Choice of RS (RS 232C Product Operated Network Interface) PONI or NET (INCOM) PONI 16 sets of oscillographic data and intermediate target data. Each set includes a graphic display of the 7 analog inputs and 24 digital logic signals. Each oscillographic target contains 1 prefault and 7 fault cycles of data. Data collection can be started by TRIP only, TRIP and/or Zone2, TRIP and/or Zone 2/ Zone 3 or DV DI Standard Features for REL 302 (Pilot) All features listed as standard for the REL 301 are also standard in the REL 302 Independent pilot zone phase and ground distance units Permissive Overreach Transfer Trip (POTT) /Simplified Unblocking Logic Permissive Underreach Transfer Trip Logic Directional Comparison Blocking Logic POTT or Simplified Unblocking Weakfeed Terminal Logic Instantaneous Forward Directional Overcurrent Function for High Resistance Ground Fault Supplement to Overreach Pilot Instantaneous Reverse Directional Overcurrent Ground Function for Carrier Start on Blocking Scheme Low voltage pickup setting for weakfeed logic and close into fault trip Reclose Block on Breaker Failure Squelch 3-Terminal Line Application Optional Features for the Non-Pilot REL 301 and Pilot REL 302 Man Machine Interface (LCD Display) Review or update all settings Review two most recent Line voltage, current and phase angle monitoring RS-232C front communications port 5 programmable contact outputs Reclosing with or without Synchronism/Voltage Check (See I.L for details) Up to 4 reclose attempts Instantaneous or time delay (each reclose attempt) Reset Timer Live-Line Dead-Bus/Dead-Line Live-Bus logic Synchronism check 120 Volt phase-to-phase synchronism voltage input option REL 301/302 CONSTRUCTION All of the relay circuitry, with the exception of the first-line surge protection, is mounted on the inner chassis, to which the front panel is attached. The outer chassis has a backplane, which is a receptacle for all external connections, including a communication interface. The integral FT-10 switches permit convenient and safe disconnection of trip, ac and dc input circuits, and provide for injection of test signals REL 301/302 Outer Chassis This is an FT-42 case, where all the input/output signals are surge protected. All external connections are made through the rear of the case (except optional front communications port). 2

21 The outer chassis (Figure 1-3) consists of 2 surge protection modules, a backplane surge protection module, a metal case, FT-switches and a communication interface consisting of a Product Operated Network Interface (PONI) which is either a NET (INCOM ) PONI or RS (RS-232C) PONI mounted on the inside of the case on the backplane module REL 301/302 Inner Chassis The inner chassis (Figure 1-4) consists of a frame, 2 switchjaws and the following modules. Each module is identified by silk screen label. PT Module: Consisting of 3 voltage transformers for V AN, V BN and V CN. CT Module: Consisting of 4 current transformers for IA, IB, IC and IP, where IP is used for zero-sequence dual-polarizing ground current measurement. Filter Module: Consisting of the anti-aliasing filters for the seven inputs from the vt and ct modules, the multiplexer to the A/D converter, the A/D converter itself, and the Opto-isolator for the input contacts. Microprocessor Module: Consisting of a microcontroller (16 bits Intel 80C196 at 10 MHz), two EPROM program memory chips; two RAM chips, an EEPROM for data retention, a real time clock with battery and indication LED s. Power Supply (PWRSUP) Module: This is an isolated switching power supply capable of supplying +5 Vdc for microcontroller and surrounding IC logic, ±12 Vdc for reference voltages and + 24 Vdc for communication. All output contacts are on this module. Three power supply options are available:48 Vdc 125 Vdc 250 Vdc Man Machine Interface (MMI)/display module (optional): consisting of a 2-line, 16 character per line, liquid crystal display (LCD), four push-buttons for setting data entries and a switch for either protection or reclosing information. If the MMI option is not supplied, the switch is supplied for resetting protection or reclosing LEDs from the front panel. Reclosing/Synch-check Module (optional): consisting of an independent microcontroller (16 bits Intel 80C196) with its IC logic, signals, contact inputs and outputs UNIQUE FEATURES Fault Detection Software REL 301/302 fault-detection software operates in two modes: Background and Fault mode. The REL 301/302 relay normally operates in the Background mode. During non-fault operation (Background mode), the REL 301/302 Microprocessor checks hardware, services the man-machine interface including communication port(s), and checks for a disturbances in voltage or current which indicates a potential fault. If a disturbance is seen, the program switches to the Fault mode, for several power cycles, to perform phase and ground unit checks for each zone and logic functions. 3

22 INSTRUCTION MANUAL REL 301/302 The REL 301/302 relay program functions are shown in a flow chart loop Figure 1-5, which the Microprocessor repeats 8 times per power cycle. Most functions are performed all of the time, in the background mode, as shown. An important detail (not shown in Figure 1-5) is that many of the checks are broken into small parcels, so that the whole complement of tasks is performed over a one-cycle period (eight passes through the loop). Some checks are performed more than once per cycle (e.g. critical timers). The REL 301/302 sampling software has 8 states; these states correspond to the sampling rate (8 samples per cycle). Movement from state to state is controlled by a timer. The timer is loaded with a state time at the beginning of the state.the code executed within a state must be completed before the timer expires. The software then waits for the timer to time out. If the timer expires before the code has completed execution, a time out error results, blocking relay tripping. The fundamental frequency components are extracted from the samples (each cycle) and converted to voltage and current phasor values using a Fourier notch-filter algorithm. During the process, the sum of squares of the inputs are accumulated to provide rms values of current and voltage. The Fourier coefficients and sums are calculated for computing the phase angles. The sum of squares and the sums of the Fourier coefficients are updated for each sample, using the information from the previous seven samples, to provide a full cycle of data Fault Mode and Restricted Fault Tests Upon entry into the fault mode, the sums of the Fourier coefficients and sum of squares from the background mode are stored. New sums are obtained, using fault data, to which offset compensation has been applied. To speed up tripping for severe faults, restricted fault testing is implemented. The last half cycle of background mode input samples and the first half cycle of fault mode input samples are used to compute the current and voltage vectors and rms values. No dc offset compensation is performed. High-set instantaneous overcurrent and Zone-1 distance unit tests are executed. Restricted fault testing can speed up tripping by as much as one cycle for high current, close-in faults, up to approximately 50% of the setting reach. Instantaneous overcurrent, inverse time overcurrent protection, and out-of-step blocking are also conducted during the fault mode and background mode. For Zone-2 and Zone-3 faults, impedance computation and checking will continue throughout the specified time delay. The impedance calculation will be performed once every cycle, in the fault mode and then continued in the background mode Unique Characteristics of REL 301/302 A unique characteristic of the REL 301/302 system is its phase selection principle. It determines the sum of positive and negative sequence currents for each phase by a novel method which excludes the influence of pre-fault load current. From this information, the fault type can be clearly identified and the actual distance to the fault can be estimated using a calculation based on the selected fault type. High-resistance ground-fault detection is available in REL 301/302. Sensitive directional pilot tripping is activated through an FDOG Timer. The pilot ground distance unit is always active and can have the priority for tripping dependent on the FDOG Timer setting. Load-loss tripping entails high-speed, essentially simultaneous clearing at both terminals of a transmission line for all fault types, except three-phase, without the need of a pilot channel. Any 4

23 fault location on the protected circuit will be within the reach of the Zone-1 relays at one or both terminals. This causes direct tripping of the local breaker without the need for any information from the remote terminal. The remote terminal recognizes the loss of load-current in the unfaulted phase(s) as evidence of tripping of the remote breaker. This, coupled with Zone-2 distance or directional overcurrent ground-fault recognition at the remote terminal, allows immediate tripping to take place at that terminal by bypassing the remaining zone 2 delay time Self-checking Software REL 301/302 continuously monitors its ac input subsystems using multiple A/D converter calibration-check inputs, plus loss-of-potential and loss-of-current monitoring. Failures of the A/D converter or any problem in a single ac channel, which unbalances non-fault inputs, causes an alarm (AL1 dropped out) and blocks tripping. Self-checking software includes the following functions: a. A/D Converter Check b. Program Memory Checksum Immediately upon power-up, the relay does a complete EPROM checksum of program memory. After power-up, the REL 301/302 continually computes the program memory checksum. c. Power-up Volatile RAM Check Immediately upon power-up, the relay does a complete test of the RAM data memory. After power-up, the REL 301/302 continually performs the RAM check. d. Non-volatile RAM Check All front-panel-entered constants (settings) are stored in non-volatile RAM in three identical arrays. These arrays are continuously checked by the program. If any of the three array entrees disagree, a non-volatile RAM failure is detected UNIQUE REMOTE COMMUNICATION PROGRAM (RCP) Special remote communications software, RCP is provided for obtaining fault, metering and current settings data as well as sending data to the REL 301/302. RCP can best be described as a user friendly way of using a personal computer (PC) to communicate with ABB protective relays by way of pull-downs menus. By coupling a computer with the appropriate communications hardware, it is possible to perform all relay setting and data interactions that are possible from the man-machine interface. RCP is required to communicate with the REL 301/302 via the communication port(s). Refer to RCP instruction manual, I.L , for detailed information ABB Bulletin Board The ABB Relay Division Bulletin Board (BBS) is now on line. To obtain the latest version of RCP software, please call the ABB BBS via modem at: (800) or (954) Using configuration settings ,400 bits/second, 8 data bits, 1 stop bit, no parity and full duplex. Once the connection is established and login is completed, choose L - Library of Files from the TOP menu. Next, select D - Down Load File, from the Library of Files, RCPxxx.EXE (where xxx is the most recent version number e.g. 180 for version 1.80). RCPxxx.EXE is a compressed, self extracting file which is expanded and installed by simply typing RCPxxx and following the instructions. 5

24 INSTRUCTION MANUAL REL 301/ SPECIFICATIONS Technical Operating Speed (from fault detection to trip contact close (60 Hz) Accuracy zone 1,2,3 pilot (302) ac Voltage (V Ln ) ac Current (I n ) Rated Frequency 12 msec (minimum) 26 msec (typical) 33 msec (maximum) ± 5% 60 Hz 70 Volt rms 50 Hz 63.5 Volt rms 1 or 5 Amp 50 or 60 Hz Maximum Permissible ac Voltage (Thermal Rating) Continuous 10 Second 1.5 x V Ln 2.5 x V Ln Maximum Permissible ac Current (Thermal Rating) Continuous 1 Second Minimum Operating Current dc Battery Voltages Nominal 48/60 Vdc 110/125 Vdc 220/250 Vdc dc Burdens: Battery ac Burdens: Voltage input Current input 3 x I n 100 x I n 0.1 x I n Operating Range Volt dc Volt dc Volt dc 7 Watts normal 30 Watts tripping 0.02 VA at 70 Vac/phase 0.15 VA at 5 A/phase External Connections Terminal blocks located on the rear of the chassis suitable for #14 square tongue lugs. Wiring to FT-10 switches suitable for #12 wire lugs Contact Rating Data Trip rated contacts - make & carry 30 amps for 1 second, 10 amps continuously, and break 50 watts resistive or 25 watts with L/R =0.045 seconds. Trip rated contacts are: Trips A1, A2 Programmable Contact OC1 Close outputs Close 1, Close 2 6

25 All other output contacts are non-trip rated - make and carry 3 amps continuously, and break 0.1 amps resistive. All contacts support 1000 Vac across open contacts Contacts also meet applicable standards: IEC A, IEC , IEC , BS Chassis Dimensions And Weight Height: " (453.7 mm) Width: 5.876" (149 mm) Depth: 6.626" (168 mm) Weight: 24 lb (16 kg.) For Horizontal Mount: 19 inch adapter plate is supplied Environmental and Type Test Data Ambient Temperature Range For Operation -20 C to +60 C For Storage -40 C to +80 C Dielectric Test Voltage 2.8 kv, dc, 1 minute (ANSI C , IEC 255-5) Impulse Withstand Level 5 kv peak, 1.2/50 msec, 0.5 joule (IEC 255-5) Fast Transient Surge Withstand Capability 4 kv, 5/50 nsec (IEC ); 5kV 10/150 nsec (ANSI C ) Oscillatory Surge Withstand Capability 2.5 kv, 1 MHz (ANSI C , IEC ) EMI Volts/Meter Withstand 25 MHz-1GHz, V/m Withstand (Proposed ANSI C ) 7

26 INSTRUCTION MANUAL REL 301/ REL 301/302 Catalog Numbers MOUNTING Horizontal H Vertical V TRIP 3-Pole Trip Self Polarized Ground Distance P CURRENT 1 A A 5 A B BATTERY VOLTAGE 48 Vdc Vdc Vdc RECLOSING Multi-shot Reclosing R Multi-shot Reclosing w/sync-check, 70V* S Multi-shot Reclosing w/sync-check 120 V** T None N PILOT SYSTEM Pilot (REL 302) P Non-Pilot (REL 301) N PROGRAMMABLE CONTACT OUTPUTS 5 Contacts including one trip rated contact None N COMMUNICATIONS PORT (PONI-Rear mounted) INCOM C RS-232C (Default) R RS-232C with IRIG-B Input B FRONT PANEL INTERFACE LCD Display L RS-232C port R Both B None N RELAY COLOR Black (Default Color) Beige E M V 3 B 1 R N 5 C L * 70V - Phase to neutral, Sync Input ** 120V - Phase to phase, Sync Input REL 301/302 ACCESSORIES FT TEST PLUG Top or Bottom (Left or Right) ID# 13B8453G05 TEST FIXTURE Inner Chassis Test Fixture 5A ID# 2678F11G04 SOFTWARE Remote Communications Program (RCP)..... ID# SWRCP01 OSCillographic And Recording (OSCAR)..... ID# SWOSC01 COMMUNICATIONS Cabling Kit ID# 1504B78G01 VERTICAL/HORIZONTAL Conversion Kit ID# 2678F11G05 8

27 Sub F39 Sheet 1 of 2 9 Figure 1-1: REL 301/302 Layout. (Vertical)

28 FILLISTER HEAD SCREW (4 SUPPLIED) INSTRUCTION MANUAL REL 301/302 Sub F39 Sheet 2 of 2 Figure 1-2: REL 301/302 Layout. (Horizontal)

29 (Use Mounting Stud For Case Grounding) (Inner Chassis Removed) Rear View Front View Figure 1-3: REL 301/302 Outer Chassis. 11

30 INSTRUCTION MANUAL REL 301/302 Figure 1-4: REL 301 Inner Chassis (Same as REL 302 vertical mount) 12

31 POWER ON -Initialization -Self-Checks Mode = Background START Sample V and I dc Offset Correction Compute V and I Phasors Using Fourier Algorithm Mode? Fault Relaying Calculations: Zone 1 and Pilot Zone Background Pilot Logic and Channel Control Disturbance in DV or D I? N - Operator Panel Interface Y Mode = Fault No Fault for 3 Cycles? Y Mode = Background - Hardware Self-Checks N Relaying Calculations - Zone 2 - Zone 3 - Out-of-Step Blinders - Inst. Overcurrent - Ground Backup - Phase Selector Checks and Logic - Non-Pilot Trip Logic - Loss-of-Pot. And Loss-of-Current - Data Communications - Contact Inputs - Programmable Output Contact Update ESK00252 dtp Figure 1-5: REL 301/302 Relay Program Functions 13

32 INSTRUCTION MANUAL REL 301/302 RESERVED FOR NOTES 14

33 Section 2. FUNCTIONAL DESCRIPTION INTRODUCTION Both the REL301/302 relay systems detect faults in three zones of phase and ground distance. Zones 1 and 2 are forward set, Zone-3 can be set forward or reverse. REL302 has a separate pilot zone (see Section 2-5). The R-X Diagram, Figure 2-1, shows a composite of characteristics available with REL301/302. Zone-1 phase and ground settings are chosen to provide substantial coverage of the protected line without overreaching the next bus. A setting of 80% of the line impedance is recommended. Faults occurring within the reach of the Zone-1 measurement cause direct tripping without regard to any action occurring at the remote terminal. Zone-2 settings are chosen to assure that faults occurring on the next bus are detected. Settings are chosen (independent of the Zone-1 settings), generally to be 120 to 150% of the line impedance. Any fault occurring on the protected line will be detected by this Zone-2 measurement (within the fault resistance and current limitations of the relaying system settings). Zone-2 tripping occurs after a time delay of T2 Definite Time or T2 Torque Control Overcurrent Time, dependent on setting choice. The Zone-3 measurement has a directional setting choice, and may be chosen to respond to forward or reverse faults. The reverse sensing option is used in conjunction with the T3 time delay, chosen to coordinate with adjacent terminal(s) Zone-2 timing. The forward sensing option produces time delayed backup to other devices sensing forward faults. Blinder measurements (B1/B4, B2/B3) are available for out-of-step blocking. The inner blinders also restrict the trip reach of all of the 3-phase fault measuring units (load restriction) LINE MEASUREMENT TECHNIQUES Line measurement techniques applied to each zone include: Single-Phase-To-Ground fault detection 3-Phase fault detection Phase-to-Phase fault detection Phase-to-Phase-to-Ground fault detection NOTE: IOM is used to supervise all ground units and IM is used to supervise all phase units, including Zone 1,2,3 and pilot for tripping Single-Phase-to-Ground Fault Single-phase-to-ground (ØG) fault detection (Figure 2-2) is accomplished by 3 quadrature polarized phase units (ph-a, ph-b, ph-c). Equations 1 and 2 are for operating and reference quantity, respectively. The unit will produce output when the operating quantity leads the reference quantity. Z 0L Z 1L V XG I X + æ è ö I0 Z ø CG Z 1L (1) 15

34 INSTRUCTION MANUAL REL 301/302 V Q (2) Three-Phase Fault where V XG = V AG, V BG, or V CG I X = I A, I B or I C Z 1L, Z 0L = Positive and zero sequence line impedance in secondary ohms. I 0 = 1/3(I A +I B +I C ) Z CG = Zone reach setting ( Zone1 G, Zone2 G, Zone3 G and Pilot G ) in secondary ohms for ØG fault V Q = Quadrature phase voltages, V CB, V AC and V BA for ØA, ØB and ØC units, respectively. Three-phase (3Ø) fault detection (Figure 2-3) is accomplished by the logic operation of one of the three ground units, plus the 3Ø fault output signal from the faulted phase selector unit. However, for a 3-phase fault condition, the distance unit computation will not include zero sequence compensation. Equations 3 and 4 are for operating and reference quantity, respectively. The unit will produce output when the operating quantity leads the reference quantity. V XG - I X Z CP (3) V Q (4) Phase-to-Phase Fault where V XG = V AG, V BG, or V CG I X = I A, I B or I C Z CP = Zone reach setting ( Zone1 Ø, Zone2 Ø, Zone3 Ø and Pilot Ø ) in secondary ohms for multi-phase faults. V Q = Quadrature phase voltages, V CB, V AC and V BA for ØA, ØB and ØC units, respectively. The phase-to-phase (ØØ) unit (Figure 2-4) responds to all phase-to-phase faults, and some single-phase-to-ground faults. Equations 5 and 6 are for operating and reference quantity, respectively. They will produce output when the operating quantity leads the reference quantity. (V AB - I AB Z CP ) (5) (V CB - I CB Z CP ) (6) where Z CP = Zone reach setting ( Zone1 Ø, Zone2 Ø, Zone3 Ø and Pilot Ø ) in secondary ohms for multi-phase faults MEASUREMENT ZONES Both REL301 and 302 perform line protection measurements for 3 zones of the transmission line (Zone-1, Zone-2, Zone-3), and for one optional pilot zone in REL302. When the REL301 or 302 system type setting SystType is set to Non Pilot, it will perform 3-zone non-pilot protection. When REL301 and 302 trip, the trip contacts will be sealed-in as long as the trip coil current exists. The trip contact dropout can be delayed by 50 milliseconds, after the trip current is removed, by inserting jumper JP4 on the Microprocessor module. See Figure 5-3 for location. Bold type in quotation marks indicates LCD display quantity. 16

35 Zone-1 Trip (Figure 2-5) For Zone-1 phase faults, the Z1P units will identify the fault and operate. The 3Ø fault logic is supervised by the load restriction logic via AND131C at AND 131. Oversight of zone-1 3Ø trip logic, via AND 131, includes supervision by the selectable out-of-step blocking (OSB) logic (see Section ) and directional supervised, by the Forward Directional Overcurrent Phase units (FDOPA, FDOPB and FDOPC) for more security during close-in faults. OSB supervision is by both the OSB logic and the subsequent OSB logic if the option is supplied and is enabled by setting OS Block to YES. Additional 3Ø fault logic supervision is by way of fault detector overcurrent input (IM) and loss of potential supervision (LOPBS) at AND 2. Loss of potential supervision is enabled by setting LOP Blk to either Yes or All. Z1P 3Ø output satisfies AND 2B, if Zone1 Ø is set to any value other than Disabled, after the zone-1 time delay T1 ( T1 Timer if set) has expired and provides a high-speed trip (HST) signal, via OR 2, to operate the trip output relay. The trip circuit is monitored by a seal-in reed relay (S), which is in-series with each tripping contact circuit. The S relay will pick up if the trip current is higher than 0.5 Amp. The operation of the S contact will turn-on the breaker trip indicators (for fault records), and feeds back to OR 4 to hold the trip relay in operation until the power circuit breaker (PCB) trips and the PCB s 52a contact opens (not shown in Figure 2-5). In the event a longer duration trip output is required, trip contact dropout can be delayed an additional 50 milliseconds, after the trip current is removed, by inserting jumper JMP4 (JP4 on the Microprocessor module). See Figure 5-3 for location. The trip seal (TRSL) signal plus the output signal from AND 2B turns on the Zone-1 phase trip indicator Zone1 Ø, for targeting plus ZONE-1 and MØ LEDs. The breaker trip and Zone-1 phase trip indicators information is stored and/or sealed in. They can be reset by external RESET voltage or through remote communications. However pushing the RESET push-button, will only return the display to METER mode and reset the flashing LEDs, but the fault target information will remain in memory. Similar operation occurs for Zone-1 single-phase-to-ground faults. The Z1G units (ØA, ØB and ØC) detect faults and operate AND 132, AND 133 or AND134 which are supervised by overcurrent fault detector IOM and ground directional unit FDOG (forward directional overcurrent ground). Zone-1 ground logic AND 3 is also supervised by the signals of NOT RDOG (reverse directional overcurrent ground) or NOT UNEQUAL POLE CLOSING or NOT LOPBS. These signals add security from incorrect operations for close-in reverse faults or operations resulting from PCB pole misalignment errors or loss of potential, respectively. Z1G output satisfies AND 3B, if Zone1 G is set to any value other than Disabled, after the zone-1 time delay T1 ( T1 Timer if set) has expired and provides a high-speed trip (HST) signal, via OR 2, to operate the trip relay. The trip seal (TRSL) signal plus the output signal from AND 3B turns on the Zone-1 ground trip indicator Zone-1 G, for targeting plus ZONE-1 and ØA, ØB or ØC LEDs. Zone-1 ground trip indicator information is stored and/or sealed in. A two-out-of-three leading phase blocking logic is included to solve the overreach problem of the single-phase ground distance units, when and if they respond to a phase-to-phase-to-ground (ØØG) fault. The high-speed trip (HST) signal also is connected to the reclosing initiation logic Zone-2 Trip (Figure2-6) For Zone-2 phase faults, the appropriate Z2P unit will detect the fault and operate the Zone-2 phase timer. The timer, denoted T2P in Figure 2-6 can be selected to be either a definite time delay or a torque controlled, inverse time overcurrent delay (CO type) characteristic*. Bold italic type indicates an output e.g. LEDs or contact output Bold type, with small capital letters, indicates an input e.g. RESET push-button or voltage input 17

36 INSTRUCTION MANUAL REL 301/302 *Note: the curves commonly used with electromechanical (e/m) overcurrent relays are a composite, average result of considerable testing. Overcurrent characteristics utilized in the REL301/302 are the result of calculations which do not exactly emulate e/m overcurrent relay characteristics. Also it should be noted that the time dial setting differs from e/m overcurrent relays. E/m relays have a continuously adjustable time dial. REL301/302 attempts to emulate this feature by providing time dial settings of 1 to 63 with the middle of the time dial range being 24 (e/m approximate equivalent of time dial 5). Timer type selection is a function of setting T2Ø Type with choices of Definite Time or Torque Control. T2Ø Time is the related Definite Time duration setting. T2Ø CV, T2Ø PkUp and T2Ø TC are the related Torque Control overcurrent delay settings. Each overcurrent delay has a choice of time delay (Reset) or instantaneous (Instant) reset. Z2P outputs (via AND 4) plus the T2P timer output satisfy AND 18. outputs satisfy AND 2B, The AND 18 output provides TDT via OR 3 if Zone-2 Ø is set to any value other than Disabled. Signal TDT satisfies OR 4 (Figure 2-5) and operates the trip relay. Load restriction, out of step blocking loss of potential and overcurrent supervision are similar to zone-1. The tripping and targeting are similar to Zone-1 trip, except for the Zone-2 phase time delay trip indicator Zone-2Ø Similar operation occurs for Zone-2 single-phase-to-ground faults. The Z2G units, OR 151 output, detects the fault and operates T2G timer. T2G timer options of Definite Time or Torque Control are identical to zone-2 phase time delays described above. Operation of IOM AND FDOG plus operation of T2G provide the TDT signal via OR 3 with Zone-2 ground time delay trip indicator. The single-phase ground distance units may respond to a ØØG fault. The output of the Z2G unit plus the operation of the ØØ selection will trip the Zone-2 Ø via OR 157, T2P ( T2Ø Time ) and AND 18. Leading phase blocking, utilized in zone-1 trip logic, is unnecessary for overreaching zones. The TDT signal is connected to the reclosing block logic. The settings for Zone-2 timers (phase and ground) are independent, and selected via the man machine interface as follows: If T2q/ Type and/or T2G Type are selected as Definite Time then Table 2 settings apply: Table 1: T2f Type and T2G Type Blocked Definite Time or Torque Control Table 2: T2f Type and T2G Type 0.10 to 2.99 Sec (Seconds) 0.10 to 2.99 sec (Seconds 18

37 If T2Ø Type and/or T2G Type are selected as Torque Control then Tables 3, 4 and 5 settings apply: Table 3: T2ø CV and T2G CV C0-2; C0-5; C0-6; C0-7; C0-8; C0-9; C0-11 Reset or Instant Table 4: T2ø PkUp and T2G PkUp 0.50 to Amps 0.50 to Amps Table 5: T2ø TC and T2G TC Zone-3 Trip (Figure 2-7) For Zone-3, phase faults, the Z3P ( Zone-3Ø ) logic will identify faults in the forward or reverse direction, depending on the Zone-3 setting, and operate the Zone-3 phase timer T3P. The Z3P output plus the T3P timer output satisfy AND 20 similar to zone-2. The AND 20 output provides TDT via OR 3. Signal TDT satisfies OR 4 (Figure 2-5) and operates the trip relay. Load restriction, out of step blocking loss of potential and overcurrent supervision are similar to zone-1. The tripping and targeting are similar to Zone-1 and Zone-2 trip, except for the Zone-3 phase time delay trip indicator Zone-3 Ø. For Zone-3 single-phase-to-ground faults, Z3G identifies the fault and operates. Z3G, plus operation of IOM, satisfies AND 7; operates T3G which provides the TDT signal via OR 3 with Zone-3 ground time delay trip indicator delay trip indicator Zone-3 G. For security, the Z3G logic is also supervised by the signal of FDOG, when Z3G is set forward or by the signal of RDOG when Z3G is set reverse via logic OR 171B, AND 171C or AND 171D. Operation for Zone-3 ØØG faults is similar to Zone-2, and is via OR 170, T3P and AND 20 gates. The TDT signal is connected to the reclosing block logic. The settings for Zone-3 timers (phase and ground) are independent, and as follows: T3P Zone-3 phase timer ( T3 Ø )0.1 to 9.99 seconds or Blocked T3G Zone-3 ground timer( T3 G )0.1 to 9.99 seconds or Blocked Either Zone-3 phase or Zone-3 ground function(s) can be disabled by setting Zone-3 Ø and/or Zone-3 G to the Disabled setting choice or by setting zone-3 phase and/or ground timers to Blocked. 19

38 INSTRUCTION MANUAL REL 301/ Zone-1 Extension (Figure 2-8) This scheme provides a higher speed operation on end zone-faults without the application of a pilot channel. If the REL301/302 SystType setting is set to Zone-1 Extension, the zone-1 phase/zone-1 ground (Z1P/Z1G) unit will provide two outputs; one is overreach which is set at 1.25 x Z1 reach by the microprocessor, and one is the normal Z1 reach. A single shot instantaneous reclosing device should be used when applying this scheme. The targets Zone-1 Ø/Zone-1G will indicate either Z1 trip and/or Z1E trip operations. The other functions (e.g., Z2T, Z3T, ac trouble monitoring, overcurrent supervision, unequal-pole closing/ load pickup control, LL trip, etc.) would function the same as in the basic scheme. For a remote internal fault, either Z1P or Z1G will detect the fault since they are set to overreach. High speed trip will be performed via the normal Zone-1 path (Figure 2-5). HST signal operates the instantaneous reclosing scheme. The breaker recloses and stays closed if the fault has cleared. Target Zone-1 Ø and/or Zone-1 G will be displayed. Once the breaker trip circuit carries current, TRSL operates the 0/5000 timer and satisfies AND 26 for 5000 milliseconds (Figure 2-8). The output signal of AND 26 will trigger the Zone-1 Ø/Zone-1 G reach circuit, constricting their reaches back to the normal Zone-1 reaches for 5000 milliseconds. During the reach constricting periods, if the breaker is reclosed on a Zone-1 permanent fault, it will retrip again. If the breaker is reclosed on an end-zone zone permanent fault, the normal Z2T time delay trip will take place. For a remote external fault, either Z1P or Z1G will detect the fault since they are set to overreach. High speed trip will be performed. HST signal operates the instantaneous reclosing scheme. The breaker recloses and stays closed if the fault has been isolated by the adjacent line breaker. However, if the adjacent line breaker fails to trip, the normal Zone-2 back up will take place. NOTE: The reaches of Z1E are based on the Zone-1 settings multiplied by a factor of NON-PILOT OPERATION The following features are standard with the REL301/ Zone Distance Phase and Ground Relay with Reversible Zone-3 Phase and Ground There are four impedance units per zone: one phase-to-phase unit and three phase-to-ground units. Zone-3 can be set to forward or reverse for carrier keying or back-up tripping in pilot system applications Inverse Time Overcurrent Ground Backup (Figure 2-9) The overcurrent ground backup (GB) unit is to supplement the distance ground protection. It provides an inverse time characteristic which is similar to the conventional CO characteristics* (Figures 2-32 through 2-38). The time curves, with a choice of time delay (Reset) or instantaneous (Instant) reset characteristic, can be selected by the GB Type Setting. The time dial is set by the GBT Curve value. The unit can be selected as directional by using the GB DIR. setting and the pickup value is set by GB Pickup. The directional GB function uses the torque control approach, as shown. The GB function can be disabled by setting the GB Type to Disabled. 20

39 Note: The curves commonly used with electromechanical (e/m) overcurrent relays are a composite, average result of considerable testing. Overcurrent characteristics utilized in the REL301/302 are the result of calculations which do not exactly emulate e/m overcurrent relay characteristics. Also it should be noted that the time dial setting differs from e/m overcurrent relays. E/m relays have a continuously adjustable time dial. REL301/302 attempts to emulate this feature by providing time dial settings of 1 to 63 with the middle of the time dial range being 24 (e/m approximate equivalent of time dial 5). The directional unit polarization is determined by the setting of Dir Type which can be set to Zero Sequence ; zero sequence voltage, Dual Polariz ; zero sequence voltage and/or zero sequence current, or Negative Sequ negative sequence voltage and negative sequence current (see Section , Selectable Ground Directional Unit, Zero Sequence / Negative Sequ/Dual Polariz) Loss of Potential Supervision (Figure 2-10) The ac voltage monitoring circuit is referred to as the loss-of-potential (LOP) circuit. In order to prevent undesirable tripping due to the distance unit(s) operation on loss-of-potential, the following logic is used: (V AN or V BN or V CN <7Vac) or (3Vo>7Vac) and not DI or not (3I O >I OS ) This means that the LOP Block will be set if any one of the phase voltages is below 7 Vac (without DI), or if the system detects 3Vo without 3Io (or 3I O > I OS ) and without 52b as shown. The loss-of-potential condition satisfies AND 1. The output signal of AND 1 starts the 8/0 millisecond timer. The timer output pickups the 0/500 millisecond timer and satisfies AND 1C if there is no output from AND 1B. Output signal of AND 1C will block all the distance unit tripping paths via AND 2, AND 3, AND 4, AND 5, AND 6, AND 172 (also blocks AND 191 and AND 187 for Pilot Systems), if LOP Blk is set to YES. All distance units are blocked from tripping but, the ground backup, regardless of it directional setting, and high-set overcurrent units (Inst Ø and Inst G) are operative and converted to non-directional operation automatically. If LOP Blk is set to All, all distance and overcurrent tripping functions will be blocked via AND 8 (Figure 2-5) and the Protection In Service LED will go out. Loss of potential blocking function can be disabled by setting the LOP Blk to No and the output of the LOP timer will operate the Alarm 1 relay (Failure Alarm) only. When applying the LOP Blk to YES, it is the intent to block all distance units from tripping, should LOP condition exist. However, under a special system condition (refer to Figure 2-11), both circuits are energized without load current; with no source at terminal B, fault near terminal A, Zone-2 relay at terminal B will be blocked by LOP, and may fail to trip. This is because the relay at B sees no current, and a low voltage condition exists before circuit breaker A opens. Another special system condition involves two parallel lines with a symmetrical sources at both terminals. For an evolving flashover fault, at a point equidistant from both terminals, the conventional LOP logic will block trip, because the first external fault generates 3V0 and not 3I 0 on the protected line. Logic AND 1A, 1B, 1C, and 1E 150/0, 3500/200 millisecond timers circuit (in Figure 2-10) are for solving these problems. This logic unblocks the LOP circuit and provides a 3500 ms trip window for the distance units to trip if the fault current is detected within 150 ms after LOP has been set. This logic has will be blocked (will have no effect) for the following conditions: if DI signal occurs ahead of LOP, or if LOP and DI signals occur simultaneously 21

40 INSTRUCTION MANUAL REL 301/ Loss of Current Supervision (Figure 2-12) The ac current monitoring circuit uses IOM and NOT Vo as criterion, as shown. Under ct short circuit or open circuit condition, IOM and NOT Vo satisfies AND 23; the output signal of AND 23 starts the 10/0.5 second timer. The timer output turns ON the non-memory LOI indicator, which can be displayed in the Metering mode, and operates the Alarm 1 relay (Failure Alarm). If the LOI condition exists and LOI Blk (LOIB) is set to YES, all trip output will be blocked after the 10 second timer times out Fault Detector Overcurrent Supervision (Figure 2-13) For REL301/302, the distance units do not require overcurrent supervision since the relay normally operates in a background mode, zone-1 and pilot impedance computation will not start until a phase current or a phase voltage disturbance is detected. This approach minimizes the load current problem when setting the phase overcurrent units. However in order to meet the traditional practice, a medium set phase overcurrent unit I M (any phase I AM, I BM, I CM ) supervises Zone-1ø, Zone-2ø, Zone-3ø and Pilot ø trip functions. This option should not be set to limit Zone-3 reach, and traditionally should be set above the load current. For coordination purposes the ground trip units Z1G, Z2G, Z3G, PLTG, and FDOG are supervised by the medium set ground overcurrent unit (IOM). The IOS logic and RDOG are used for carrier send in a Pilot Blocking system (REL302) Highset Overcurrent Trip (Figure 2-14) The instantaneous overcurrent units (IAH, IBH, ICH and IOH) are forward directional and set high to detect those faults which occur in the Zone-1, therefore, their tripping will occur via OR 2 since these trips are classified as high speed trips. These high set trip functions can be disabled by setting the Inst Ø (ITP) phase and/or Inst G (ITG) ground to Disabled. The directional characteristic of Inst Ø and Inst G will automatically revert to non-directional protection if the setting of Dir Type = Zero Seq or Negative Seq, if the LOP condition occurs and the setting of LOP Blk is YES. If LOP Blk is set to ALL, ITP and/or ITG will be blocked. For the setting of Dir Type = Dual Polariz when lp > 1amp, the ITG maintain their directionality determined by the current polarization calculation (3I 0 and I P ). For I P < 1amp, the directionality is determined by the voltage polarization calculation (3V 0 and 3I 0 ). In order to avoid a false trip during the clearing of a reverse fault, an ITG transient block logic is added. The ITG trip will be delayed for 2 cycles if a forward fault is detected immediately after a reverse fault Close-Into-Fault Trip (CIFT Figure 2-15a) There are three low voltage units (LVA, LVB and LVC) in REL301/302. Each unit senses the phase voltage condition in the background mode. The units can be set ( Low V ) from 40 to 60 volts, in 1.0 volt steps. For any phase voltage below the set value, the LV logic will produce a logic 1 output signal. The low voltage units are used in CIFT and the pilot weakfeed logic in REL302. In order to supplement distance unit operation, when the circuit breaker is closed into a fault and line side potential is used, the Close-Into-Fault Trip logic operates as shown in Figure 2-15a. It includes logic AND 22, 100/180 millisecond and 16/0 millisecond timers. If any overcurrent unit (IAL, IBL, ICL or IOM) operates OR 11, at the same time as one of the phase voltages (VA, VB,VC) is below the preset level of the LV units, (for 180 ms) after circuit breaker closing (52b contact opens), then logic AND 22 is satisfied and produces a trip signal. Tripping is classified as Time Delay Trip, via OR 3, (Figure 2-6, 2-7) which will produce a Reclose Block signal and a CIF Trip target. CIF Trip has three setting possibilities: CIF Trip, No CIF Trip (dis- 22

41 or CIF Trip w/delay (enable with time delay insertion). The application of close into fault with time delay, is explained in the following paragraphs. A modified close into fault logic is employed for the special application shown in Figure 2-15b. Two relays, looking in opposite directions, control a single breaker, share a single 52b input and a common set of voltage transformers. Each relay trips the main breaker and the power transformer secondary breaker, for faults on the line section being protected (e.g. relay #2 trips 52 and 52-2). Classic close into fault logic produced false tripping of one secondary breaker (transformer on the unfaulted line section) upon reclosing after a trip, if the fault persisted. This was due to arming of the non-directional, close into fault logic by the common (main breaker) 52b, in the relay which did not detect the fault. The 200/0 millisecond timer delays the arming and hence operation of the close into fault logic during main breaker reclosing. The choice of 200 milliseconds was selected to be greater than the 180 milliseconds reset of the 52b, but less than minimum reclose dead time of an instantaneous reclose. To utilize this logic, the following application rules apply: 1) For relay 1 with bus-side potential, that is cts and vts on the same side of the main breaker, set CIF Trip to No CIF Trip. When bus-side potential is used, close into fault logic is not needed and could misoperate, under certain circumstances, if enabled. 2) For relay 2 with line-side potential, that is cts and vts on opposite sides of the main breaker, set CIF Trip to CIF Trip w/delay. The minimum reclose dead time must be greater than 200 milliseconds or close into fault tripping will be delayed, and it is possible no close into fault trip will occur when reclosing onto a fault. 3) Loss of potential block logic, LOP Blk must be set to Yes or No not ALL. For the setting of LOP Blk ALL, the relay may not trip during reclosing onto fault since loss of potential may set and block tripping. Standard close into fault trip logic, without time delay, should be selected for all applications with line side potential other than this two-relay-one-breaker scheme configuration Unequal-Pole-Closing-Load Pickup Logic (Figure 2-16) The ground units may pick up on a condition of load pickup or with unequal breaker pole closing. The high speed ground units (Z1G, FDOG and PLTG) should be supervised under this condition. This supervision is achieved by inserting a 0/20 millisecond timer, controlled by the 52b signal, to supervise the Zone-1G trip via AND 3 (Figure 2-5) PLTG trip via AND 189A (Figure 2-20). It should be noted that the 20 ms time delay will have no effect on a normal fault clearing Loss-of-Load Accelerated Trip Logic (LL Trip Figure 2-17) NOTE: The LL Trip function does not need to be set for normal operation of the relay. While it can provide faster tripping for end-zone faults, it may not be used in all situations. It should be applied with caution based on thorough knowledge of the system characteristics where the relay is applied. It is definitely not applicable where maximum tapped load may exceed minimum through-load in the protected line. Load loss accelerated tripping is acceleration of or bypassing the remainder of the normal zone-2 time delay after a fault is sensed in zone-2 and the logic detects 3-pole tripping at the remote terminal. Acceleration occurs for all fault types, except 3Ø faults, to improve trip speed for the sequentially tripping terminal. 23

42 INSTRUCTION MANUAL REL 301/302 During non-fault conditions, balanced 3Ø current flowing results in IAL=IBL=ICL= logic 1 which produces a logic 1 at the output of AND 24 and OR 13. For a remote fault (beyond zone-1 reach), Z2P OR Z2G detects the fault which satisfies an input to AND 25. However, the signal from AND 24 is negated at it s input to AND 25, therefore, AND 25 should have no output until the remote end 3-pole trips. At this time, the local end current will lose one or two phases, depending on the type of fault. The AND 24 output signal changes from 1 to 0 and satisfies AND 25. After 10 milliseconds, this output by-passes the remaining T2 timer, and provides accelerated Zone-2 trip. The (10/0 millisecond) time delay is for coordination on external faults with unequal pole clearing. The 0/32 millisecond timer is needed for security on external faults without load current condition. Target LL Trip will turn on after load loss trip. The load loss trip function is selected by setting LL Trip to YES, FDOG or NO, where YES is load loss trip with zone-2 supervision only; FDOG is load loss trip with both zone-2 and (FDOG/I OM ) supervision; NO disables the load loss trip function Current or Voltage Change Fault Detector (DI, DV) The REL301/302 relay normally operates in the Background mode, while there is no phase current or voltage disturbances. During background mode, the four input currents (I A, I B, I C and I p ) and the three voltages (V A, V B, V C ) are sampled at a rate of 8 per cycle. When a phase disturbance (DI or DV) is detected, the relay enters fault mode for several cycles to perform phase and ground unit distance computation for each zone. The criteria for determining a disturbance in the REL301/302 design are as follows: 1) Each phase D I:if [I Kn - I (K-1)n ] > 1.0 amp And [I Kn - I (K-1)n ] / I (K-1)n x 100% > 12.5% 2) Each phase DV:if [V Kn - V (K-1)n ] > 7.0 volts and [V Kn - V (K-1)n ] / V (K-1)n x 100% >12.5% 3) D I 0 : if [(3I 0 ) Kn - (3I 0 ) (K - 1)n ] > 0.5 amp Where: n = Relative sample number 0,1, 2, 3, 4, 5, 6, 7 K = Cycle number relative to a disturbance start K-1 = Cycle number before the disturbance start Phase Directional Polarization The phase directional units have no setting selection. Forward phase directionality is derived from the phase angle relationship between the faulted phase current and the non-faulted phase-to-phase voltage. The connection is referred to as a 90 connection since the sensed phase current, at a power factor of 1, leads the sensed phase-to-phase voltage by 90 under non-fault conditions. Forward direction operate area can be defined as the faulted phase current between 30 leading to 150 lagging its 1 power factor position. Directional calculation maximum torque output, results when the phase current lags it s 1 power factor position by 60. Often this is referred to as a characteristic Ground Directional Polarization Selection The ground directional unit setting Dir Type has three selections Zero Sequence, Negative Sequ and Dual Polariz, which sets the polarization of the forward directional overcurrent ground (FDOG) unit and reversed directional overcurrent ground (RDOG) unit. If Zero Sequence is selected, both FDOG and RDOG units will be operated by a zero-sequence voltage polarizing element. Forward direction is identified by 3I 0 leading 3V 0 between 30 o and 210 o. The sensitivity of this element is 3I 0 > 0.5 amp and 3V 0 >1.0 vac. If Negative Sequ is select- 24

43 ed, both FDOG and RDOG will be operated by negative sequence voltage polarizing element. In this case the maximum sensitivity for the forward directional unit is I 2 leading V 2 by 98 o, with V 2 >1.0 Vac and 3I 2 > 0.5 Amp. If Dual Polarization is selected, the FDOG and RDOG will be determined by current polarizing directional element(i P ) if the input current I P is greater than 1 amp. The I P is connected to FT switch #12 and switch #13 and it is also connected to the power transformer neutral (ct). The maximum torque angle between 3I 0 and I P equals zero degrees, i.e., the forward direction is identified and 3I 0 leads I P by 0 to 90 or lags by 0 to 90. The sensitivity of this element is 3I 0 > 0.5 and I P > 1.0 amp. If I P is less than 1 ampere, the FDOG will be determined by the zero sequence voltage polarizing calculation Instantaneous Forward Directional Overcurrent Ground (FDOG) and Phase (FDOP) Units The instantaneous forward directional overcurrent ground function (FDOG) is a directional unit depending on the setting of Dir Type as described in the preceding Section FDOG in combination with IOM, supervises Zone-1, Zone-2, Zone-3 Pilot zone ground units for security purpose, and also for pilot high resistance ground fault trip (FDOG/Iom). The phase directional unit (FDOP) is based on the angular relationship of a single-phase current and the corresponding pre-fault phase-to-phase voltage phasors. The forward direction is identified if the current phasor leads the voltage phasor. The pair of current and voltage phasors which are compared are I A and V BA (FDOPA), I B and V CB (FDOPB), I C and V AC (FDOPC). The three-phase fault detection of Zone1 and pilot are supervised by FDOPA, FDOPB and FDOPC. The high set currents I AH, I BH, I CH are supervised by FDOPA, FDOPB and FDOPC, respectively Instantaneous Reverse Directional Overcurrent Ground (RDOG) Similar to FDOG, the instantaneous reverse directional overcurrent ground function (RDOG) supervises the ground units to prevent false tripping Programmable Reclose Initiation and Reclose Block Logic (Figure 2-18) The REL301/302 system provides the following contact output for Reclosing Initiation and reclosing block functions: RI2, used for Reclosing Initiation on trip RB, used for Reclosing Block The operation of RI2 and RB contacts is controlled by the setting of the programmable Reclosing Initiation logic. The operation of either RI2, or RB must be confirmed by the signal of TRSL, which is the trip seal of REL301/302 operation. The most common Reclosing Initiation practice is to have Reclosing Initiation on high speed (Pilot, Zone-1 and high set overcurrent) trip only. On Pilot version programming can be accomplished by closing the EXT. (External) PILOT ENABLE switch and setting the Pilot to YES. AND 84 will produce logic to operate the RI2 relay when receiving signals from TRSL and AND 89. The program is further controlled by the RI Type setting: RI Type setting NO RI: 3PRN provides no output, therefore, will not operate RI2. 25

44 INSTRUCTION MANUAL REL 301/302 RI Type setting ØG RI:3PRN will provide output 1 on single-phase-to-ground fault only and will operate RI2. RI Type setting ØØ, ØG, RI:3PRN will provide output 1 on single- phase- to- ground fault or 2-phase faults, and will operate RI2. RI Type setting 3Ø, ØØ, ØØG, ØG RI: 3PRN will provide output 1 on any type of fault, and will operate RI2. The Zone-1, Pilot and Highset overcurrent Fast RI, Zone-2 RI (Z2RI) and Zone-3 RI (Z3RI) settings are provided for programming on applications where the Reclosing Initiation on High-speed, Zone-2 or Zone-3 trips are desired. Logic AND 62A is controlled by the signal of 3PRN, therefore, the setting of ØG RI, ØØ, ØG, RI and 3Ø, ØØ, ØØG, ØØ RI also affect the Fast RI, Zone-2RI and Zone-3RI. In general, the Reclosing Block (RB) relay will operate on TDT (Time Delay Trip) or OSB (Out-of-Step Block condition). However, it will be disabled by the setting of Fast RI, Z2RI, and Z3RI signal Output Contact Test A Push-to-Close feature is included in order to check all output relay contacts, which include TRIP, BFI, RI2, RB, AL1, AL2, GS, Carrier Send (Pilot), Carrier Stop (Pilot) and each programmable contact output (if supplied). The relay contact check is supplementary to the self-check because the Microprocessor self-check routine cannot check the output hardware. In order to enable the contact test, jumper JP5 on the Microprocessor module must be in place. (See Section for detailed procedures.) Out-of-Step Block Logic (Figures 2-19a & 2-19b) The Out-of-Step Blocking (OSB) logic (power swing block supervision) in REL301/302 is a double blinder scheme. It contains two blinder units, providing 4 blinder lines. (See Figure 2-19b.) The nature of the logic (shown in Figure 2-19a) is that the outer blinder 21BO must operate 50ms or more ahead of the inner blinder 21BI, in order for an OSB condition to be identified. Blinder reaches are determined by the setting of OS Inner and OS Outer, respectively. The OSB signal is a negated input to the AND 131 (Z1P), AND 147 (Z2P), AND 160 (Z3P), and AND 176 (PLTP) for supervising the 3-phase distance tripping. In addition to controlling the OSB logic, the blinder units are also used to supervise distance relay tripping (Load Restriction). Phase distance unit tripping cannot take place unless 21BI operates. This prevents operation of the distance relay on load. The OSB signal is also applied to the reclosing logic for initiating RB. Blinder Line Polarizing Operating Left -j(vxg + IXRC (Ang Pos. 90 ) IX (Ang Pos. 90 ) Right j(vxg - IXRC (Ang Pos. 90 ) IX (Ang Pos. 90 ) 26

45 The following quantities are used for the blinder sensing: where V XG = Phase to ground voltage, VAG or VBG I X = Phase current in ØA or ØB R C = Setting of the unit OS Inner for 21BI (R T )or OS Outer for 21BO (R U ). Ang Pos. = The positive sequence line impedance angle. Operation occurs if the operating voltage leads the polarizing voltage. The characteristics are as shown in Figure 2-19b Subsequent Out-of-Step Security Logic Model power system tests, when using a motor generator set, show that the Zone-1 impedance unit may overreach or respond to a reversed fault. This was attributed to motor generator set instability following delayed clearing on an external fault. The Zone-1 relay, in all cases, identified the fault location and type correctly and responded much later to the swing condition. Logic was added, OR 131A, AND 131B, AND 131C and OR 122A, utilizing the inner blinder and Zone-1 sensing sequence, plus a 50 millisecond timer (as shown in Figure 2-19a) to differentiate between a fault and a subsequent out-of-step condition. This logic will not affect normal Zone-1 trip time, nor will it affect normal out-of-step blocking Fault and Oscillographic Data Fault Data The following sections explain the mechanisms for data capture and retrieval. As mentioned in Section 1.5, communication port access requires Remote Communications Program (RCP) software. REL301/302 systems capture the latest sixteen fault data records in non-volatile memory. That is, all records are saved even if control power is removed from the system. The two most recent fault data records can be accessed via the front panel MMI. All sixteen fault data records can be accessed via the communication port(s). Complete details concerning communication port usage is contained in Section 4.6. For a detailed listing of fault data information see Table 4-3. When a fault occurs, the MMI mode is switched to L-FLT mode and is set to provide information on the most recent fault (Latest Fault). By pressing either the RAISE or LOWER push-buttons, the fault data, for L-FLT may be reviewed. Also, when the fault occurs, the LEDs related to L-FLT (e.g. ZONE-1 and AG LEDs) flash. LEDs flash, until reset, at a once per second rate indicating one fault record exists, and at a twice per second rate indicating more than one fault record exists. Pressing the SELECT push-button once, will change the MMI display mode to P-FLT and allow access to the second most recent fault record (Previous Fault). By pressing the RAISE or LOWER push-buttons, the fault data, for P-FLT may be reviewed. Pressing the RESET push-button will reset the LED target indicators and cause the display to return the METER mode. Pressing the RESET push-button does not erase the stored target data. 27

46 INSTRUCTION MANUAL REL 301/302 Fault data capture is initiated by one of the following selections of Flt Data setting: Trip data captured only if trip action occurs Zone-2 data captured if Zone-2 logic operates or any trip action occurs Zone-2, Zone-3 data captured if Zone-2 or Zone-3 logic operates or any trip action occurs Oscillographic Data REL301/302 systems capture the latest sixteen oscillographic data records in volatile memory. That is, all records are lost if control power is removed from the system. Oscillographic data records can only be accessed via the communications port(s). Oscillographic data records consist of 8 cycles of 8 analog quantities and 24 digital quantities taken at a frequency of eight samples/cycle. The 8 cycles of information is comprised of one cycle of pre-trigger and 7-cycles of post-trigger data. When the data is retrieved, using RCP, it can be displayed in it s ASCII tabular form and saved as a file for display at a later time. The file can also be used for graphical display of the user s design or by using the Oscillographic Capture and Recording (OSCAR) software. Oscillographic data is initiated by one of the following selections in the OSC Data : Trip data taken only if trip action occurs Zone-2 data taken if Zone-2 units pick up or any trip action occurs Zone-2, Zone-3 data taken if Zone-2 or Zone-3 units pick up, or any trip action occurs. dv or di data taken if DI, DV, Zone-2 or Zone-3 units pick up, or any trip action occurs NOTE: See Section for DV D I definition REL302 PILOT SYSTEM NOTE: The external Pilot Enable Switch (PLT ENA) must have voltage applied in conjunction with the Pilot setting set to Yes to enable the pilot system Pilot System Type As mentioned in Section 2.3.4, choice of system type is controlled by the setting Syst Type. Both the REL301/302 have system type selection settings as shown below: Non Pilot 3 zone distance (REL301 and REL302) Zone-1 Extension (REL301 and REL302) POTT Permissive Overreach Transfer Trip/Simplified Unblocking (REL302 only) PUTT Permissive Underreach Transfer Trip (REL302 only) Blocking Directional Comparison Blocking (REL302 only) The following settings are recommended for POTT and BLOCKING systems: 28

47 Osc Data Zone-2, Zone-3 Flt Data Trip FDOGTime 3 cycles or longer Pilot Ø & Pilot G 150% overreach the next bus Zone-1 Ø & Zone-1G 80% of the protected line Zone-3 Ø & Zone-3G 100% of the reversed line Zone-3 Reverse Dir. (required setting) Permissive Overreach Transfer Trip/Simplified Unblocking (Figures 2-20, 2-21, 2-22) If the system type setting Syst Type is set to POTT, REL302 will perform either the POTT scheme or the Simplified Unblocking scheme, depending on the applied pilot channel. The basic operating concepts of a POTT scheme are: 1) Pilot distance measurement units PLTP and PLTG ( Pilot Ø and Pilot G ) are set to overreach the next bus. 2) Pilot channel is a frequency shift type device; its signal may be through either metallic wire, leased telephone circuits, power line carrier, microwave or fiber optic channels. 3) Transmitter frequency should be different at each terminal: channel is normally operated on a guard frequency; and the channel frequency will be shifted from guard to trip when the pilot relay(s) are operated; and pilot trip is performed when the pilot relay(s) operate and a pilot trip frequency signal from the remote end is received. The basic operating concepts of a Simplified Unblocking scheme are the same as the POTT scheme, except for differences in applied pilot channel equipment. In an unblocking scheme, the pilot channel is a frequency-shift type power line carrier. The transmitter frequency must be different at each terminal. It is normally operated on a blocking frequency and will be shifted to an unblocking frequency when the pilot relay(s) operate. The carrier receiver should provide logic for which, in the event of loss-of-channel or low SNR ratio, the pilot trip circuit is automatically locked out after a short time delay. Pilot trip is provided, however, if the tripping distance relay(s) operate during this short time period between loss-of-channel and pilot trip lockout. Pulsar Technologies Inc. type TCF-10B Power Line Carrier receiver provides this logic; it provides a 150 ms trip window, then automatic lockout after loss-of-channel. Provision for a second high-speed pilot trip is provided, for the situation when a permanent fault causes a permanent loss-of-channel and the breaker closes onto the fault. The operating concepts of the pilot distance measurement units PLTP and PLTG are the same as for the non-pilot zone distance measurement units, and are supervised by the same LOPBS, OSB, IOM, FDOP, and FDOG units, as shown in Figure The pilot phase and/or pilot ground function(s) can be disabled by setting the Pilot Ø and/or Pilot G to Disabled. The POTT and Simplified Unblocking schemes include the following types of logic: a. Tripping logic (Figure 2-21) 1) For a forward external fault, the local pilot distance measurement units PLTP or PLTG detect the fault, operates and keys the pilot channel. The output from OR 40 will satisfy the first input to AND 30. Assuming that TBM (POTT) does not operate and PILOT ENABLE (see Figures 2-21 and 2-31 for definition) is set, then three out of four inputs of AND 30 29

48 INSTRUCTION MANUAL REL 301/302 are satisfied, but pilot trip cannot occur since the remote transmitter is still sending a guard (or blocking frequency) signal. CR input to AND 30 is not satisfied. 2) For an internal fault, the pilot relays at both ends PLTP or PLTG, or the zone-1 relays Z1P or Z1G, detect the internal fault and operate and together with the received trip (or unblocking frequency) signal CR, via AND 44 (Figure 2-22), satisfy AND 30 (Figure 2-21). PT (Pilot Trip) output of AND 30, will cause high speed tripping via OR 2 (Figure 2-5). Targets of pilot phase trip or pilot ground trip will result after the breaker trips (TRSL). b. Carrier Keying Logic (Figure 2-22) 1) Forward Fault Keying For a forward internal or external fault, the local pilot relays PLTP or PLTG, or the zone-1 relays Z1P or Z1G, detect the fault operates OR 40 or OR 25, and causes pilot channel SEND reed relay to operate, via AND 35, if PILOT ENABLE is set. Operation of the SEND relay will key the local transmitter, shift the transmitting frequency from guard to trip (or from a blocking to an unblocking), which allow the remote pilot relay system to trip. 2) Echo Keying Since the POTT and the Simplified Unblocking schemes require the receiving of a permissive signal from the remote end, for pilot trip, provision is made for the condition when the remote breaker is opened. When the breaker is opened, three of the inputs of AND 34B (Figure 2-22) are satisfied by the NOT FORWARD (from OR 14), NOT REVERSE (from POTT-TBM) and 52b. Channel receive from either RCVR-1 (2 terminal system configuration) or RCVR-1 and RCVR-2 (3 terminal system configuration, Figure 2-28) will produce an output from AND 34B (ECHO) which will cause a SEND signal via OR 18. This echo keying will be continue for 150 millisecond or less if any inputs to AND 34B change state (e.g. receive input stops). 3) Signal Continuation This logic includes an input from the TRSL signal and a 0/150 millisecond (ms) timer. The 0/150 ms signal continuation time is required to keep the local transmitter at the trip frequency (or unblock frequency) for 150 ms after the local end high speed trips which includes pilot trip, zone-1 trip, and high-set overcurrent trip, in case of sequential trip on the system. This logic will be disabled by a time delay trip (TDT) for 300 ms after the trip decision (AND 34A), and will be blocked from operation by close into fault trip (CIF, AND 49A). c. Carrier Receiving Logic (Figure 2-22 and 2-28) This logic includes RCVR-1 input, OR 15, AND 63 and AND 44, for 2 terminal system configuration. RCVR-2 input is through OR 21 from AND 63A (Figure 2-28) for 3 terminal system configuration. Output trip (or unblocking) frequency signal from the channel receiver operates the logic and produces a channel receive (CR) signal. d. Channel Indicators (Figure 2-22) The target indicating channel send Car Send, will be stored after the send decision has been made and the breaker trips. The target indicating a receive operation, Rx Ch1 will be stored after the breaker trips and a carrier trip signal is received from the receiver. e. Reverse (Transient) Block and Unblock Logic (TBM, Figure 2-16) 30

49 For a loop system or a parallel line application, power reversal may introduce problems for a pilot relay system especially when a 3-terminal line is involved, since the pilot distance units may have to be set greater than 150% of the line impedance in order to accommodate the infeed effect from the tapped terminal. Pilot distance units may operate for an external fault on the parallel line when the third source is out of service. The TBM block and unblock logic solves this problem. There are some other typical cases of the protected line being tripped by a ground directional relay upon clearing of a fault in the adjacent (but not parallel) line. When the adjacent line breaker trips, it interrupts the current in the faulted phase as well as the load current in the unfaulted phases. Dependent on the direction of this load current, and the contact asymmetry of the breaker, there can be a short pulse of load-derived I o with possible tripping direction polarity, which provides an electrical forward-torque to the ground directional relay. Therefore, it is desired to increase TBM security by adding the transient block timer (0/50) logic. This security is included automatically for POTT schemes. Note for the TBM logic to function correctly: Zone-3 must be set in the reverse direction ( Zone-3 set to Reverse Dir. ), zone-3 phase ( Zone-3 Ø ) and zone-3 ground ( Zone-3 G ) distance, should be set to 100% of the reverse line impedance. f. Channel Simulation (Figure 2-22) The MMI TEST mode provides the capability to simulate the SEND ( SEND ) logic for keying action without the operation of pilot relay units. Also receiver inputs 1 ( Rx1 ) and 2 ( Rx2, Figure 2-28) can simulate receiving of a permissive trip or unblocking frequency signal without the operation of the remote transmitter. Receiving of both channels can be simulated if Rx1, Rx2 is selected. See Section 5.2 for details. g. Programmable Reclosing Initiation (Figure 2-18) The basic programmable reclose initiation application is as described in Section However, on pilot systems, to activate the reclose initiate output RI2, for any high-speed trip, the EXT. PILOT ENABLE SW. (Figure 2-18) must be satisfied, and the setting FAST RI should be set to Pilot/Z1/Inst I. The operation will occur via the logic AND 89, AND 84 as shown in Figure Permissive Underreach Transfer Trip (Figure 2-23) If a permissive underreaching transfer trip (PUTT) system is desired, the system type setting Syst Type, is set to PUTT. Basic operating concepts of a PUTT scheme are: 1) Pilot distance measurement units PLTP and PLTG ( Pilot Ø and Pilot G ) are set to overreach. The pilot channel is a frequency-shift type device, and the transmitter frequency is different at each terminal. 2) The pilot channel is normally operated with a guard frequency, the channel frequency will be shifted from guard to trip when the zone-1 distance measurement units Z1P or Z1G operate, and pilot trip is performed when the pilot relay PLTP or PLTG operates, together with the receiving of a carrier trip signal from the remote end. PUTT includes the following logic: a. Pilot Tripping Logic 31

50 INSTRUCTION MANUAL REL 301/302 The Pilot Tripping Logic for the PUTT scheme is the same as for the POTT scheme (Figures 2-20, 2-21). b. Carrier Keying Logic 1) Forward fault keying (Figure 2-23) For a forward end zone fault, the PUTT scheme will not key except when the internal fault is within the zone-1 reach. This means that the PUTT scheme keys only on Zone-1 faults. Keying is via AND 46, AND 33, OR 18 and AND 35. 2) Signal continuation (Figure 2-23) Same as for POTT scheme. The TBM logic is not required because the carrier keying units are set to underreach. NOTE: For open breaker condition, the echo keying will not work due to lack of the SEND signal from the remote terminal for an end zone fault. The remote terminal relies on Zone-2 to clear the fault. c. Programmable Reclosing Initiation (Figure 2-18) Same as for POTT scheme. d. Carrier Receiving Logic (Figure 2-29) Same as for POTT scheme except as shown. e. Channel Indicators (Figure 2-22) Same as for POTT scheme except recorded as PUTT Directional Comparison Blocking (Figure 2-24) If a directional comparison blocking (Blocking) system is desired, the system type setting Syst Type, is set to Blocking. Refer to Section for other recommended settings for Blocking systems. Basic operating concepts of a Blocking system are: 1) Pilot distance measurement units PLTP and PLTG ( Pilot Ø and Pilot G ) are set to overreach the and the zone-3 distance measurement units Z3P/Z3G ( Zone-3 Ø / Zone-3 G ) must be set in the reverse direction to detect reverse external faults for carrier start and Reverse Block Logic (TBM). 2) Pilot channel is an ON-OFF type power line carrier. Transmitter frequency at each terminal can be the same. Channel is normally OFF until a disturbance is detected (DV, DI) which will cause a SEND output for a minimum of 65 milliseconds via AND 50. Continued sending will occur as the result of any reverse logic operating via OR 41 and continuation for 50 milliseconds after the reverse logic resets. 3) Pilot tripping is performed when pilot distance measurement units operate and a carrier blocking signal is not received. The Blocking system, as shown in Figure 2-24, includes the following logic: a. Tripping Logic (Figure 2-24) 1) For a forward internal fault, the local pilot distance measurement units PLTP or PLTG detect the fault and which causes an output from OR 40 stopping the channel send circuit (DI, DV starts the carrier before the distance measurement units operate), via OR 16, SQ timer (0/150 ms) and AND 50. (The receiver receives the signal from both local and remote trans- 32

51 mitters.) At the same time, output of OR 40 will satisfy one input of AND 48 and also starts the Channel Coordination Timer (BLKT). (See Section 3.2.7e for BLKT setting.) After the preset time of the channel coordination timer, logic AND 47 will satisfy AND 48, if there is no received carrier signal from either remote or local, and if the local transient block is not set (0/50 timer input to AND 51). If PILOT ENABLE (Figure 2-21) and AND 48 are satisfied, AND 52 will produce pilot trip. Pilot trip target would be recorded the same as for POTT. 2) For a forward external fault, the local pilot distance measurement units PLTP or PLTG detects the fault and operates in the same manner as for a forward internal faults. However, at the remote terminal, the carriers units DI/DV/ Reverse Z3P/Z3G/RDOG also detect this external fault and operates the SEND relay, which keys the carrier transmitter, sending the blocking signal to the remote terminal(s) via OR 41, AND 51, OR 18, and AND 35. The local receiver receives the blocking signal, disables the output of AND 47; and prevents pilot tripping. 3) A timer 50/8 and OR47 are added between the RCVR and AND47. This logic is to overcome the fact that the receiver (RCVR) input may drop out momentarily due to the external fault clearing noises. b. Carrier Keying Logic 1) Reverse fault keying (Figure 2-24) 2) For a reverse fault, the DI and DV will operate and begin transmitting the blocking signal and if local reverse looking measurements units, Reverse Z3P/Z3G or RDOG detects the fault, operation of the Send relay, continues sending the blocking signal to the remote terminal(s). NOTE: The use of DI and DV for carrier start provides more security to the blocking scheme by starting carrier in approximately 4-6 milliseconds. 3) This SEND circuit includes logic AND 173, OR 41, AND 51, AND 50, OR 18 and AND 35. The logic of OR 222A and the 32/0 ms timer circuit is to stop the internal fault SEND on a weakfeed terminal condition. 4) Since the present keying practice on carrier systems use either the contact open (negative or positive removal keying) or contact close (positive keying) approach, a form-c dry contact output for SEND is provided in REL302. 5) Signal continuation and TBM logic For a reverse fault, both the local carrier start relay(s) and the remote pilot relay(s) detect the fault and operate. The local carrier start relay(s) start the carrier and send a blocking signal to block the remote pilot relay from tripping. After the fault is cleared by the external breaker, the remote breaker may have a tendency to trip falsely if the carrier start unit resets faster than the pilot trip unit. The 0/50 ms timer between the AND 41D and AND 51 continues the SEND signal for 50 ms after the carrier start units have been reset. This logic also provides transient block and unblock (TBM) effect for power reversal on parallel line applications. The subsequent out-of-step condition, as described in Section , may cause the reverse looking units to fail to operate on external faults, and introduce false pilot tripping at the remote terminal(s). Additional logic has been added to the design which includes OR 41C, 32/0 ms timer, AND 41B and OR 41 to prevent false tripping. It utilizes the not FDOP (or FDOG) and LV condition (LV units can be set between 40 and 60 volts) to initiate the TBM circuit; and sends a blocking signal to the remote terminal(s). Setting OS Block to YES supervises AND 41B when this additional logic is required. 33

52 INSTRUCTION MANUAL REL 301/302 6) Internal fault preference and squelch On a close-in fault, the carrier start logic may operate and start the transmitter. This operation may block the system from pilot tripping. The negating signal from OR 16 to AND 50 will provide an internal fault preference feature to prevent this problem. The squelch 0/150 millisecond timer is required for improving the problem if the local breaker tripped faster than the remote breaker on an internal fault. The logic prevents SEND from operating for 150 ms after any high speed tripping, including pilot trip, zone-1 trip and instantaneous overcurrent trip. c. Channel Receiving Logic (Figure 2-24) Channel receive signal, from the receiver output, will be directly applied to AND 47 to disable the pilot tripping function. d. Channel Indication (not shown in Figure 2-24) Since the carrier channel turns ON for external faults only, the channel indicators for send and receive will not be recorded. e. Channel Simulation Same as for POTT scheme. f. Programmable Reclosing Initiation (Figure 2-18) Same as for POTT scheme Pilot Ground Overcurrent Pilot Ground Overcurrent Supplement is added for high resistance faults and improves security on POTT/unblocking schemes on some special power system conditions, such as shown in Figure A ØØG fault is on the paralleled line section. Due to the system condition, fault current flowing in the protected line would be I1+I2 from A to B, and Io from B to A. The operation of pilot distance relays would be a phase relay at A and a ground relay at B. The result would be erroneous directional comparison of an external fault as an internal one. The POTT/unblocking scheme will incorrectly trip the protected line. REL302 POTT/Unblocking pilot ground unit is supervised by the reverse-looking ground unit RDOG as shown in Figure 2-31 (REVERSE BLOCK LOGIC). At terminal A, the RDOG disables the PILOT KEY and PILOT TRIP functions via AND 35 and AND 30. Terminal B will not receive a signal for permissive trip since none is sent. The reverse-block logic also provides the conventional TBM feature to prevent false operation on power reversal. It should be noted that a BLOCK-THE-BLOCK logic is also included in the circuit, as shown in Figure The BLOCK-THE-BLOCK logic is to prevent the REVERSE BLOCK LOGIC from over-blocking. If the breaker is unequal-pole closing on a ØØG fault, say pole-a, pole B and C close at a later time (see Figure 2-26). If, due to breaker contact asymmetry, the first breaker contact to close is the one of the faulted-phase, the zero-sequence (or negative sequence) polarizing voltage will initially have a polarity opposite to its fault-derived polarity. Reverse looking ground unit could pick-up, start the reverse block logic and maintain it for 50 ms causing the correct tripping to be delayed. The BLOCK-THE-BLOCK logic prevents this delay. The Reverse Block Logic also includes the reverse looking Zone-3 Ø /Zone-3 G (Z3P/Z3G) logic as shown in Figure

53 High Resistance Ground Fault Supplement (Figure 2-27) Supplemental protection is provided on overreaching pilot systems to detect high resistance ground faults. The instantaneous forward directional overcurrent ground function FDOG works in conjunction with the pilot ground distance unit. The FDOG directional unit operation is determined by the setting of Dir Type. Refer to Section for the setting of Dir Type. FDOG is supervised by the Iom setting. A coordination timer FDOGTime (FDGT) is provided to allow preference for pilot ground distance unit operation. The delay time can be set from 0 to 15 cycles in 1 cycle steps. It is recommended to set the FDOGTime to 3 cycles or longer due to the sensitivity of FDOG Instantaneous Reverse Directional Overcurrent Ground Similar to FDOG, the instantaneous reverse directional overcurrent ground function RDOG supplements the pilot zone logic Supplement to Carrier Ground Start, Blocking Scheme In the blocking system, RDOG, supervised by IOS, provides additional ground fault detection (high resistance) beyond what is available by Z3G (reverse looking) for carrier start Pilot Ground Start, POTT In the POTT/UNBLOCK systems, RDOG supervises PLTG and prevents keying or tripping on reverse faults terminal Line Application For Blocking 3-terminal line applications, since the frequency of the 3 transmitters are the same, any one transmitter starting will block the pilot system from tripping, therefore, logic for the 3-terminal pilot system would be the same as that used for the 2-terminal system. However, for POTT/Unblock and PUTT systems, since the transmitter frequencies are different at each terminal, logic for the second receiver (RCVR-2) is added to the system when the application involves 3-terminal lines. Setting 3-Term. should be set to YES when a 3-terminal line system is required. a. Additional Logic For POTT and Simplified Unblocking (Figure 2-28) This logic includes a contact converter (CC) for RCVR-2, AND 55, and logic for the second receiver indication (not shown). Voltage applied to RCVR-2 operates the contact converter and produces the channel receive signal (CR) from AND 63A via AND 55 and AND 64 which allows pilot tripping (Figure 2-22, OR 21). b. Additional Logic for PUTT (Figure 2-29) The additional logic for PUTT is similar to that described for POTT scheme, except logic includes AND 56, AND 57 and 50/0 millisecond timer. Since Zone-1 reach dictates transmitting of the permissive signal, the fault could possibly be detected by only one remote terminal. For a close-in Zone-1 fault, only the local terminal can key its transmitter and the other two may not. This logic provides a CR pilot trip signal for 50 ms for, system security, if either channel is received. For a fault which is detected by relays at both remote terminals, AND 55 logic will not be satisfied, then channel (CR) will be performed via the logic which allows pilot tripping (Figure 2-22, OR 21). 35

54 INSTRUCTION MANUAL REL 301/ Weakfeed Trip Application a. Block/Weakfeed Special logic for a weakfeed terminal is not required for Blocking systems since Blocking systems requires no permissive trip signal from the remote end, even though the remote end is a weakfeed terminal. The strong end has no problem tripping for an internal fault. The weak end is usually assumed either as a no feed source, for which it does not need to trip on an internal fault, or it can pilot trip sequentially. NOTE: For the case of OS Block is set to YES, Weakfeed should be set to YES if this terminal can become a weak terminal (e.g. certain system configurations). Refer to Figure 2-24, logic AND 41B and OR 41C. b. PUTT/Weakfeed The logic for a weakfeed terminal is not required for the PUTT system. Because the PUTT system uses underreaching relay(s) only for pilot trip keying, it is not necessary to apply weakfeed logic. c. POTT/ Weakfeed For POTT and unblocking schemes, at the weak source terminal, the Zone-3Ø /Z3G distance relays should be set for reverse-looking, and the undervoltage units (LVA, LVB, LVC) should be used. The basic operating principle of the weakfeed trip logic for the POTT and simplified unblocking scheme is as follows: 1) Echo key for trip permission (Figure 2-30) On internal faults, the strong terminal(s) send the permissive (or unblocking) frequency signal to the weak terminal, and the strong terminal(s) pilot trip logic will trip, once echo trip permission is received from the weak terminal. The pilot trip relay(s) at the weak terminal cannot operate since there is insufficient fault energy, and does not perform the normal keying function. With one weakfeed condition, when the weak end receives a permissive (or unblocking) signal, the output from the receiver operates the echo key logic via AND 65A, providing both pilot relay (from OR 40) and reverse logic (from REVERSE BLOCK LOGIC) have not operated and if system disturbance is detected (DV ordi). Output of AND 65A will key the weak terminal transmitter to the permissive (or unblocking) frequency via OR 18, AND 35. On weak end reverse external fault, the strong source terminal(s) send the permissive (or unblocking) frequency signal to the weak end, and the strong source terminal(s) pilot trip relay(s) wait to receive the echo trip permission from the weak end. However, at the weak end, the echo key logic AND 65A will not operate, because of the REVERSE BLOCK LOGIC operation. Both the strong/weak terminals will not trip on this external fault. 2) Weak end trip on internal fault (Figure 2-30) The output of AND 65A (echo keying) together with no output from OR 40 (pilot trip relays), no output from the REVERSE BLOCK LOGIC and with output from OR 44 (low voltage condition) will satisfy AND 66. Weakfeed trip (a high speed trip) will occur after 50 ms via OR 2 (Figure 2-5). The time delay is for coordination because the voltage trip units are non-directional Weakfeed System Application For weakfeed applications, an inherent part of the logic requires reverse fault detection; Zone-3 Ø/Zone-3 G and RDOG, which are a part of the REVERSE BLOCK LOGIC, supply this requirement. 36

55 Reclose Block on Breaker Failure Squelch For a pilot system, the BFI signal can be used to stop (for a blocking system) or start (for permissive schemes) the carrier channel and allow the remote terminal to trip should the local breaker fail to trip. The problem is how to inhibit the remote terminal from reclosing. REL301/302 solves this problem by the with the RemBF RB squelch logic in the reclosing initiation logic. The logic, as shown in Figure 2-18, includes AND 61A and a 132/0 millisecond timer. If the RemBF RB is set to Yes the logic will initiate reclose block (RB) 132 ms after the fault is detected by DV or DI, assuming the pilot is enabled and the TRSL signal is received on any pilot trip operation PROGRAMMABLE CONTACT OUTPUTS Most of the functions described in this section can be directed (single or combined) to the programmable contact outputs. Refer to Section 4.10 for further details. 37

56 INSTRUCTION MANUAL REL 301/302 Sub A57 Figure 2-1: REL301/302 Characteristics/R-X Diagram Sub A13 Figure 2-2: Mho Characteristic for Phase-to-Ground Faults 38

57 Sub A14 Figure 2-3: Mho Characteristics for Three-Phase Faults (No Load Flow) Sub A15 Figure 2-4: Mho Characteristics for Phase-to-Phase and Two Phase-to-Ground Faults (No Load Flow) 39

58 INSTRUCTION MANUAL REL 301/302 AND ì INPUTSí A = îb Notes: AND OUTPUT INPUTS A 0 0 I I B 0 I 0 I OUTPUT SIGNAL ON ALL INPUTS REQUIRED TO PROVIDE AN OUTPUT I Active state of a signal (may be defined as positive or negative voltage or current) 0 Inactive state of a signal (reference) = Can have more than two (2) inputs I ELECTROMECHANICAL CONTACT EQUIVALENT A B = INCLUSIVE OR ì INPUTSí A OR = îb OUTPUT INPUTS A 0 0 I I B 0 I 0 I OUTPUT 0 I I I ELECTROMECHANICAL CONTACT EQUIVALENT A B SIGNAL INPUT WILL PRODUCE AN OUTPUT ALL INPUTS PRODUCE AN OUTPUT = NEGATION (NOT) INPUT INPUT OR OUTPUT OUTPUT INPUTS OUTPUT 0 I I 0 ABSENCE OF INPUT SIGNAL PRODUCES OUTPUT TIMERS INPUT TP TD OUTPUT Input changes to Active State 1 - Output changes to Active State After Time Delay On Pickup (TP) Input Changes to Inactive State 0 (Only After Having Been Active) - Output Changes to Inactive State After Time Delay On Dropout Figure 2-5a: Logic Drawing Symbols 40

59 Sub A49 Figure 2-5b: Zone-1 Trip Logic Sub A50 Figure 2-6: Zone-2 Trip Logic 41

60 INSTRUCTION MANUAL REL 301/302 Sub B49 Figure 2-7: Zone-3 Trip Logic Sub A64 Figure 2-8: Zone-1 Extension Scheme 42

61 * Sub A63 Figure 2-9: Inverse Time Overcurrent Ground Backup Logic * Sub A64 Figure 2-10: Loss-of-Potential Logic * Denotes Change 43

62 INSTRUCTION MANUAL REL 301/302 Sub A18 Figure 2-11: Loss-of-Potential Logic (System Diagram) Sub A54 Figure 2-12: Loss of Current Monitoring Logic 44

63 Sub A66 Figure 2-13: Overcurrent Supervision * Sub A65 Figure 2-14: Instantaneous Overcurrent Highset Trip Logic * Denotes Change 45

64 INSTRUCTION MANUAL REL 301/302 Sub A55 Figure 2-15a: REL301/302 Close-Into-Fault Trip (CIFT) Logic Sub A32 Figure 2-15b: Special Application for CIF Logic with Time Delay Pickup Sub A56 Figure 2-16: Unequal-Pole-Closing/Load Pickup Trip Logic & Reverse Block (TBM) Logic 46

65 Sub A59 Figure 2-17: Load Loss Accelerated Trip Logic Figure 2-18a: Reclosing Initiation Logic Sub B51 Sub A25 Figure 2-18b: Out-of-Step Block Logic (Blinder Characteristics) 47

66 INSTRUCTION MANUAL REL 301/302 Sub B50 Figure 2-19: Out-of-Step Block Logic Sub A63 Figure 2-20: REL302 POTT/Unblocking, PUTT and Blocking Pilot Relay 48

67 Sub A67 Figure 2-21: REL302 POTT/Unblocking and PUTT Pilot Trip Logic Sub B52 Figure 2-22: REL302 Channel Sending/Receiving Logic in POTT/Unblocking Schemes 49

68 INSTRUCTION MANUAL REL 301/302 Sub A62 Figure 2-23: REL302 Channel Sending /Receiving Logic in PUTT Scheme * Sub B53 Figure 2-24: REL302 Blocking System Logic * Denotes Change 50

69 Sub A17 Figure 2-25: Power Reversal on POTT/Unblocking Schemes Sub A29 Figure 2-26: Unequal Pole Closing on Fault 51

70 INSTRUCTION MANUAL REL 301/302 FDOG TRIP Sub A65 Figure 2-27: REL302 Pilot Ground Trip Supplemented by FDOG Sub A68 Figure 2-28: REL302 Additional Logic for POTT/Unblocking Schemes on 3-Terminal Line Application 52

71 Sub A69 Figure 2-29: REL302 Additional Logic for PUTT Scheme on 3-Terminal Line Application *Sub B54 Figure 2-30: REL302 Weakfeed Application * Denotes Change 53

72 INSTRUCTION MANUAL REL 301/302 Figure 2-31: REL302 Reversible Zone-3 Phase and Ground (Reverse Block Logic) Sub B55 54

73 I.L Section 3. SETTING CALCULATIONS 3.1. MEASUREMENT UNITS AND SETTING RANGES DISTANCE MEASUREMENTS Three variable mho phase-to-ground units and one variable mho phase-to-phase impedance unit per zone. Three Zones Phase and Ground Distance (Zone-1, 2, 3): ohms in 0.01 ohm steps for 5 A (ct type) ohms in 0.05 ohm steps for 1 A (ct type) Any Zone (phase or ground distance) can be disabled Zone Timers Separate timers for phase and ground: Zone-1 (0 to 15 cycles in 1 cycle steps) Zone-2 (0.10 to 2.99 seconds in 0.01 second steps, Blocked of Torque Control Overcurrent) Zone-3 (0.10 to 9.99 seconds in 0.01 second steps, Blocked) Forward Directional Ground Timer (FDOGTime) (0 to 15 cycles in 1 cycle steps, Blocked) OVERCURRENT MEASUREMENTS One ground directional ( Inst. G ) 1 and one phase directional ( Inst. Ø ) high-set overcurrent setting for (I AH, I BH, I CH, I OH ): in 0.5 A steps for 5 A (ct type) in 0.1 A steps for 1 A (ct type) Three-phase non-directional overcurrent units (I AL, I BL, I CL ) for Load Loss Trip and Close-Into Fault Trip with one setting ( Low IØ ). One ground overcurrent unit ( 3I0s ) for Loss Of Current monitoring. Three non-directional medium set overcurrent units (IA M, I BM, I CM ) for phase distance supervision with one setting ( IM ). One non-directional medium set ground overcurrent unit (I 0M ) for ground distance supervision with one setting ( 3I0m ) in 0.1 A steps for 5 A (ct type) in 0.02 A steps for 1 A (ct type) Three inverse time overcurrent phase units with CO type characteristics (see Figures 2-32 through 2-38) for Zone-2 phase torque control, time delay: Pickup ( ) in 0.1 A steps for 5 A (ct type). Choice of 7 time-curve families (CO-2, 5, 6, 7, 8, 9, 11 Characteristics), 63 curves per family with instantaneous or time delay reset. (Pickup ( ) in 0.02 A steps for 1 A (ct type).) One inverse time overcurrent ground unit with CO characteristics (see Figures 2-32 through 2-38) for Zone-2 ground torque control, time delay: Pickup ( ) in 0.1 A steps for 5 A (ct type). Choice of 7 time-curve families (CO-2, 5, 6, 7, 9, 11 Characteristics), 63 curves per family with instantaneous or time delay reset. (Pickup ( ) in 0.02 A steps for 1 A (ct type).) 1. Bold type in quotation marks indicates LCD display quantities 55

74 INSTRUCTION MANUAL REL 301/302 One inverse overcurrent ground unit with CO characteristics (see Figures 2-32 through 2-38) for ground backup: Pickup ( ) in 0.1 A steps for 5 A (ct type). Choice of 7 time-curve families (CO-2, 5, 6, 7, 8, 9, 11 Characteristics), 63 curves per family with instantaneous or time delay reset. Set for directional or non-directional operation. (Pickup ( ) in 0.02 A steps for 1 A (ct type).) One forward set instantaneous directional overcurrent ground unit. (REL 302 only, Pilot-high resistance ground faults, supervised by I OM ).) One reverse set instantaneous directional overcurrent ground unit. (REL 302 only, Carrier Start, Weakfeed and Transient Block Logic, supervised by I OS.) UNDERVOLTAGE MEASUREMENTS ( Low V ) Three under-voltage units (L VA, L VB, L VC ) for Close-Into-Fault and Weakfeed Trip (REL 302 only) supervision with one setting Low V. 40 to 60 Vrms in 1 - Volt steps. OHMS PER UNIT DISTANCE ( X / Dist ) For fault locator measurement in Ohms per Distance Unit (Kilometers or Miles) in primary ohms. OUT-OF-STEP BLOCK ( OS Block ) OUT-OF-STEP BLOCK Override Timer ( OSOT ) ms in 16 ms steps OUT-OF-STEP BLOCK Inner Blinder ( OS Inner ) Ohms in 0.1 Ohm steps NOTE: The inner blinder (RT) is a required setting since it is used as a load restriction blinder even when OUT-OF-STEP BLOCK is not used. OUT-OF-STEP BLOCK Outer Blinder ( OS Outer ) Ohms in 0.1 Ohm steps 3.2. CALCULATION OF REL 301/302 SETTINGS The following REL 301/302 setting calculations correspond to the setting categories in the Installation Section (4). Assume that the protected line has the following data: miles Line reactance 0.8 ohms/mile (primary ohms) 69 kv, 60 cycles Positive and negative sequence impedances: ZIL (Pri) = Z2L (Pri) = 15Ð77 o ohms Zero sequence impedance: Z0L (Pri) = 50Ð73 o ohms 56

75 I.L Current Transformer Ratio: (ct Ratio) RC = 1200/5 = 240 (set ct ratio = 240) Voltage Transformer Ratio: (vt Ratio) RV = 600/1 = 600 (set vt ratio = 600) Relay secondary ohmic impedances are: Z = Z pri x R C /R V Z1L = Z2L = 15Ð77 X 240 = 6 Ð77 ohms 600 Z 0L = 50Ð73 x 240/600 = 20Ð73 ohms Ratio of Zero and Positive Sequence Impedances (ZR) Z 0L /Z 1L = 20/6 = 3.33 Then REL 301/302 will automatically calculate the zero sequence current compensation factor (k 0 ) by using the value of Z 0L /Z 1L, Ang Pos., Ang Zero and reference to equation 1 in Section i.e., NOTE: The setting range of ZOL/ZIL has been expanded from to in 0.1 steps. Also the setting ranges of Ang Pos. (Positive sequence line impedance angle) and Ang Zero (Zero sequence line impedance angle) have been expanded from to as well. These changes were made to accommodate a wide variety of system components and configurations. However, the selection of each setting has to be carefully considered if the maximum fault current is 200 Amperes (secondary or above). If the maximum fault current is 200 Amperes (secondary) the following restrictions must be observed: ZOL/ZIL less than or equal to 7.5 The setting difference of Ang Pos - Ang Zero = 50 or less If the maximum fault current is less than 200 Amperes (secondary) these restrictions do not apply Zone-1 Distance Settings k 0 =Z ( 0L Z 1L )/Z 1L = ( Z OL Z 1L ) Ð (AngZero AngPos) 1 A setting of 80% of the line impedance for Zone-1 reach is recommended, thus the Zone-1 phase and ground reach should be Zone-1 Ø = 6 x 0.8 = 4.8 OHMS and Zone-1 G = 6 x 0.8 = 4.8 OHMS NOTE: Zone-1 Ø and Zone-1 G can be set for different values if the application requires. As stated above, start with a setting of 80% of the line impedance for the Zone-1 reach setting. Adjustment of the Zone-1 reach (line percentage) should be considered if any of the following are true: 57

76 INSTRUCTION MANUAL REL 301/302 1) If the calculated Zone-1 impedance is 0.5 ohms (secondary) or less the line percentage, used for the calculation, should be 70-75%. 2) If the Source Impedance Ratio or SIR, (ratio of positive sequence source impedance to positive sequence line impedance) is in the range of 3-5 the line percentage, used for the calculation, should be no more than 75%. 3) Circuit fault impedance angles in the range of 80 degrees produce dc time constant of about one cycle. One cycle time constants result in maximum overreach error of about 16%. Hence the line percentage used should be no more than 70-75%. If the total fault impedance angle is greater than 86 degrees, the dc time constant is greater than 2.3 cycles, and the overreach error is reduced to 10 percent or less. The same is true if the fault impedance angle is less than 75 degrees. If system fault impedance angles are known to be either above 86 degrees or below 75 degrees, the line percentage, used for the Zone-1 calculation, can be increased by 5 percent.(all angles are based on 60 Hz systems.) See figure 3-1. NOTE: The fault impedance angle is fixed and is a measurement of the line characteristic, therefore the fault impedance angle is the angle of current looking from the relay into the fault. 4) If CCVT s, of the low-capacitance type, (e.g s vintage PCA-5 and PCA-8 designs) are in use, the line percentage, used for the Zone-1 calculation, should be 70-75%. Severe subsidence-transient related overreach has been noted in cases where low-capacitance CCVT s are used in short line applications. An alternative to reducing the Zone- 1 setting, is to introduce a Zone-1 time delay (T1) of one or two cycles and using the 80 percent Zone-1 reach calculation Zone-2 Distance Settings Generally, Zone-2 reach is set for 100% of the protected line plus 50% of the shortest adjacent line. If the shortest (or only) adjacent line primary impedance is 20 ohms, then the Zone-2 reach setting would be: Zone-2 Ø = 6 + (20 x 0.5) x 240/600 = 10 OHMS and Zone-2 G = 6 + (20 x 0.5) x 240/600 = 10 OHMS NOTE: Zone-2 Ø and Zone-2 G can be set for different values if the application requires Zone-3 Distance Settings Generally, Zone-3 reach is set for 100% of the protected line plus 100% of the longest adjacent line emanating from the remote bus, while accounting for the infeed from the same remote bus. If the longest (or only) adjacent line from the remote bus is 25 ohms primary, and the infeed effect may increase its impedance by 30%, then the Zone-3 reach setting should be: Zone-3 Ø = 6 + (25 x 1.3) x 240/600 = 19 OHMS and Zone-3 G = 6 + (25 x 1.3) x 240/600 = 19 OHMS 58

77 I.L Overcurrent Settings a. IL Low-set Phase Overcurrent. The low set phase overcurrent unit is used for supervising the load-loss-trip and close into fault functions. It should be set higher than the line charging current and below the minimum load current. NOTE: It should be set above the maximum tapped load current if applicable. Assume that the line charging current is negligible for this line section and the minimum load current is 2.0 Amps secondary, then the low set phase overcurrent unit setting should be: Low IØ = 1 Amps b. IM Medium-set Phase Overcurrent. The medium set phase overcurrent unit is used for supervising the out of step blocking function and all phase distance tripping functions. Care in selecting the medium set phase overcurrent setting ( IM ) must be exercised to prevent limiting the Zone-3 distance reach. Traditionally, IM is set higher than load current whenever possible. In general, the criteria for setting medium set phase overcurrent is 1.13 X Maximum load current. Assume maximum load current is 4.0 amps secondary then: IM = 4.0 Amps X 1.13 = 4.5 Amps (approximately) The setting should be reviewed to assure it does not limit the reach of zone-3. c. IOS Low-set Ground Overcurrent. The low-set ground overcurrent unit is used for supervising the reverse directional overcurrent ground unit (RDOG). It should be set as sensitive as possible. A setting of 0.5 amperes is recommended: 3I0s = 0.5 Amps d. IOM Medium-set Ground Overcurrent. The medium set ground overcurrent unit is used for supervising all ground distance units, the forward directional overcurrent ground unit (FDOG). Generally, it is recommended to be set 2 times the 3I0s setting. 3I0m = 2 x 3I0s = 1.0 Amps e. ITP High-set Phase Overcurrent / ITG High-set Ground Overcurrent. The directional high set overcurrent phase and ground units, Inst. Ø and Inst. G are used for direct tripping functions. The general setting criterion for the instantaneous direct trip unit is: The unit should be set higher than 1.15 times the maximum fault on the remote bus, where the factor of 1.15 is to allow for the transient overreach. For this example, assume that the maximum load is not higher than the maximum forward end zone fault current, and the maximum phase and ground fault currents on the remote bus are 20 and 24 amperes, respectively, then the settings of the high-set phase (ITP) and the high-set ground (ITG) should be: Inst. Ø = 20 x 1.15 = 23 Amps Inst. G = 24 x 1.15 = 27.6 Amps 59

78 INSTRUCTION MANUAL REL 301/ Out-of-Step Block ( OS Block ) Blinder Settings ( OS Inner and OS Outer ) The requirements for setting the blinder units are: Inner blinder must be set to accommodate maximum fault resistance for internal 3-phase fault Inner blinder should not operate on severe stable swings Outer blinder must have adequate separation from inner blinder for fastest out-of-step swing to be acknowledged as an out-of-step condition Outer blinder must not operate on load a. Setting the Inner Blinder If the out of step blocking (OSB) is used to supervise tripping of the 3Ø unit on heavy load current, the inner blinder 21BI must be set sufficiently far apart to accommodate the maximum fault arc resistance. A reasonable approximation of arc resistance at fault inception is 400 volts per foot. If a maximum ratio of line voltage per spacing is 10,000 volts/ft. for a high voltage transmission line, and if a minimum internal 3-phase fault current is calculated as: I min. = [E / 1.73(Z A +Z L )] where Z A is maximum equivalent source impedance, Z L is line impedance and E is line-toline voltage. then R max = 400 x FT / I min. = 400 x 1.73(Z A +Z L )/10000 = (Z A +Z L ) Adding a 50% margin to cover the inaccuracies of this expression: R max. R S = 0.104(Z A +Z L ) primary ohms = 0.104(Z A +Z L )R C /R V secondary ohms Set inner blinder to: OS Inner = R T = R S x COS (90 o - PANG) (1) This is the minimum permissible inner blinder setting when it is used to provide a restricted trip area for a distance relay. Another criterion that may be considered is based upon the rule of thumb that stable swings will not involve an angular separation between generator voltages in excess of 120 o. This would give an approximate maximum of: OS Inner = (Z A +Z L +Z B )/ (2x1.73) (2) = 0.288(Z A +Z L +Z B ) primary ohms OS Inner = 0.288(Z A +Z L +Z B )R C /R V secondary ohms where Z B is the equivalent maximum source impedance at the end of the line away from Z A. An inner blinder setting between the extremes of equations (1) and (2) may be used. This provides operation for any 3-phase fault with arc resistance, and restraint for any stable 60

79 I.L swing. Except in those cases where very fast out-of-step swings are expected, the larger setting can be used. It will usually be possible to use the minimum inner blinder setting of 1.5 ohms. b. Setting the Outer Blinder For slow out-of-step swings, a reasonably close placement of outer to inner blinder characteristic is possible. The separation must, however, be based on the fastest out-of-step swing expected. A 50 ms interval is inherent in the out-of-step sensing logic, and the outer blinder must operate 50 ms or more ahead of the inner blinder. Since the rate of change of the ohmic value manifested to the blinder elements is dependent upon accelerating power and system WR 2, it is impossible to generalize. However, based on an inertia constant (H) equal to 3, and the severe assumption of full load rejection, a machine will experience (assuming a uniform acceleration) an angular change in position of no more than 20 o per cycle on the first half slip cycle. If the inner blinder were set for (0.144 Z T), and the very severe 20 o per cycle swing rate were used, the outer blinder should be set for approximately: OS Outer = 0.5 Z T primary ohms (3) where Z T = Z A + Z B + Z L This is the minimum setting of the outer blinder for a 20 o per cycle swing rate Timer Settings (Definite Time Setting) a. Zone-1 has an adjustable definite time timer, T1 Timer which is normally set to 0 cycles. The zone-1 timer could be used to delay tripping when coordinating with a slower operating device at a remote terminal. The timer also can be used to delay tripping for coordination of relay systems at the same terminal when the coordination is with a slower device. b. Zone-2 timers, for phase and ground, have two choices of time delay type. Choices are definite time ( T2Ø Type and T2G Type set to Definite Time ) or zone-2 torque controlled, time delay overcurrent ( T2Ø Type and T2G Type set to Torque Control ). Torque control overcurrent time delays will be discussed in Section Zone-2 definite time delay ( T2Ø Time and T2G Time ) settings should be coordinated with the Zone-1 and other high-speed trip units on the adjacent line terminals. Coordination Time Interval of 0.3 to 0.5 seconds is recommended. For example, if T2Ø Time and T2G Time of 0.4 seconds is used, then the phase and ground Zone-2 timers should be set as follows: T2Ø Time = 0.4 seconds and T2G Time = 0.4 seconds NOTE: T2Ø Time and T2G Time are separate timers; they can have different time settings if the application requires. 61

80 INSTRUCTION MANUAL REL 301/302 c. Zone-3 timers ( T3Ø Time and T3G Time ) settings would be similar to the above. For example, if T3 of 0.8 seconds is required, then the phase and ground Zone-3 timers should be set as follows: T3Ø Time = 0.8 seconds and T3G Time = 0.8 seconds NOTE: T3Ø Time and T3G Time are separate timers; they can have different time settings if the application requires. d. For Out-of-Step Block ( OS Block ), if applied, the Out-of-Step Block Override Timer Setting ( OSOT ) is determined by the power system operation. Its range is 400 to 4000 ms, in 16 ms steps. e. For the REL 302 blocking system only, the channel coordination timer setting ( Blk Time ) is based on the following application criteria: Blk Time > (Slowest remote carrier start time + channel time + margin) - (the fastest local 21P/21NP pickup time) Where channel time includes the transmitter and receiver times, and the times which occur between these devices, e.g., wave propagation, interfacing relays, etc. For REL 302: fastest 21P/21NP pickup time = 14 ms slowest carrier start time = 4 ms suggested margin time = 2 ms For example, the REL 302 channel coordination timer should be determined as shown below, if the channel time is 3 ms. Blk Time = ( ) - 14 = -5 i.e., set Blk Time = Timer Settings (Torque Control Overcurrent) Zone-2 timers, for phase and ground, can be set for a timed overcurrent delays. Zone-2 torque controlled, time delay overcurrent ( T2Ø Type and T2G Type set to Torque Control ) provides access to seven sets of overcurrent curves which are similar to ABB CO curves. Three settings T2Ø CV, T2Ø PkUp and T2Ø TC must be determined to apply phase torque controlled overcurrent protection. Similar settings are required for the ground torque controlled overcurrent protection. a. T2Ø CV - Zone-2 phase overcurrent curve family setting. Seven sets (families) of CO type overcurrent curves are provided and shown in Figures 2-32 through As with any overcurrent function, curve family selection is based on the application and coordination with other overcurrent devices. Setting the family setting is by choosing CO-2, C0-5, CO-6, CO-7, C0-8, CO-9 or CO-11. Each of the curve sets offers a choice of reset characteristic which is explained below. b. T2Ø PkUp - Zone-2 phase overcurrent pickup setting. In general, the pickup setting is set above maximum load current and below maximum phase fault current. For maximum sensitivity, the pickup should be set as close to maximum load current as possible. Pickup setting range is Amps. 62

81 I.L c. T2Ø TC - Zone-2 phase overcurrent curve selection setting. This setting can also be referred to as the time dial setting. As shown in Figures 2-32 through 2-38, T2Ø TC is settable in steps of one from 1 to 63. As with any overcurrent function, curve time dial is based on the application and coordination with other overcurrent devices. Similarly, three settings T2G CV, T2G PkUp, T2G TC must be determined to apply ground, torque controlled overcurrent protection. Similar to any overcurrent application, the same criteria as in a, b, and c above are used to select appropriate settings for ground, torque controlled overcurrent protection. The following equations can be used to calculate the trip time for all phase and ground backup curves K T2f TC T (sec) = T (for I P >1.5 x T2Ø PkUp ) ( I P C) P , 000 K T2GTC T (sec) = T (for 3I0 >1.5 x T2G PkUp ) ( 3I 0 C) P , 000 R T (sec) = (for 1< 3I P < 1.5 x T2Ø PkUp ) ( I P 1) T2f TC 24, 000 R T (sec) = (for 1 < 3I 0 < 1.5 x T2G PkUp ) ( 3I 0 1) GBT Curve 24, 000 Where: I PF 3I I P = of T2Æ PkUp 3I 0 = T2G PkUp I PF = Applied fault current 3I 0F = Applied zero sequence fault current T2Ø PkUp = Phase pickup current setting (0.50 to 10.0 Amps) T2Ø TC = Phase time dial curve setting (1 to 63) T2G PkUp = Ground pickup current setting (0.50 to 10.0 Amps) T2G TC = Ground time dial curve setting (1 to 63) T 0, K, C, P and R are constants, and are shown in Table 3-1 Torque control of the overcurrent functions is by way of the operation of zone-2 phase and/or ground distance logic operating. When a zone-2 distance decision is made, the overcurrent logic is enabled and the curve timing begins. Operation time of the zone-2 distance (phase or ground) decision must be added to the overcurrent trip time calculated above. Since zone-2 operate time is approximately 22 milliseconds, add 22 milliseconds to the times calculated for total trip time. 63

82 INSTRUCTION MANUAL REL 301/302 REL 301/302 offers two reset characteristics for the torque control overcurrent functions, instantaneous or time delayed. Instantaneous reset, as the name implies, means reset with no intentional time delay. Time delay reset function is a linear characteristic shown in Figure 3-9 and is intended to replicate the reset characteristics of electromechanical overcurrent relays REQUIRED SETTINGS APPLICATION The following settings are determined by the application. They do not require calculation Oscillographic Data ( OSC Data ) Capture Setting The OSC setting is for selecting one of the 4 choices, TRIP, Z2TR, Z2Z3 or DIDV, to initiate the oscillographic data taken, where: TRIP data taken only if trip action occurs. Z2TR data taken if Zone-2 units pick up, or any trip action occurs. Z2Z3 data taken if Zone-2 or Zone-3 units pick up, or any trip action occurs. DIDV data taken if DI, DV, Zone-2 or Zone-3 units pick up, or any trip action occurs. NOTE: The setting of DIDV, for OSC is not recommended since data will be collected for all disturbances including normal operations Fault Data ( Flt Data ) Capture Setting Is for selecting one of the 3 ways TRIP, Z2TR, Z2Z3 to initiate the fault data taken, where: TRIP to store fault data only if trip action occurs. Z2TR to store fault data if Zone-2 units pick up or any trip action occurs. Z2Z3 to store fault data if Zone-2 or Zone-3 units pick up or any trip action occurs Current Transformer Ratio Setting ( CT Ratio ) The CT Ratio is used for the fault distance calculation and load current monitoring, if it is selected to be displayed in primary amperes. It has no effect on the protective relaying system. For this example, set CT Ratio = Voltage Transformer Ratio Setting ( VT Ratio ) The VT Ratio is used for the fault distance calculation and system voltage monitoring, if it is selected to be displayed in primary volts. It has no effect on the protective relaying system. For this example, set VT Ratio = Frequency Setting ( Freq. ) Should be selected to match the power system operating frequency. For this example, set Freq. = 60 64

83 I.L Current Transformer Type Setting ( CT Type ) Provides the flexibility for 5 amp or 1 amp rated current transformer selection. For this example, set CT Type = 5 since a 5 amp current transformer is used. The setting of CT Type affects all the distance unit and overcurrent unit setting ranges. The ranges will be automatically changed as listed in Table Read Primary Setting ( Read Out ) The Read Out should be set to Primary Units if all the monitoring ac voltages and currents are selected to be displayed in primary KV and KA values, respectively. Select Secondary Units to view voltages and currents in relay or secondary values. NOTE: When reading secondary units only one digit will read out after the decimal point. When reading primary units RP must be set to yes Ohms Per Unit Distance ( X / Dist ) The line reactance setting X / Dist is the multiplier for fault distance calculation. It has a range of 0.3 to 1.5 ohms (primary) in steps. In this example, the line reactance is 0.8 ohms/mile; set X / Dist = 0.8 Ohms. The fault distance calculation is as follows: VT Ratio Z S sinðfang Flt Dist = CT Ratio X / Dist Where Z S is the secondary impedance magnitude, and FANG is the fault angle Distance Type ( DistUnit ) Setting Distance type ( DistUnit ) has a selection of MILE or KM. It should be selected to match with the setting of X / Dist. For this example, select DistUnit = MILE Reclosing Mode ( RI Type ) Setting RI Type is for selecting the reclosing mode. It has four setting positions, No RI, ØG RI, ØØ,ØG RI', 3Ø, ØØ, ØØG, ØG RI. Refer to the guidelines for reclosing mode programming for the RI Type setting selection in Section Reclose Initiation Settings Fast RI, Zone-2 RI and Zone-3 RI provide the selectivity for High speed tripping units, Zone-2 and Zone-3 reclosing initiation, respectively. See Section for details Remote Breaker Failure, Reclose Block ( RemBF RB ) For a pilot system (REL 302 only), set RemBF RB to Yes if reclose block output to prevent the remote breaker from reclosing for local breaker. 65

84 INSTRUCTION MANUAL REL 301/ Remote Pilot Control ( Pilot ) Setting Pilot set to Yes combines with the signal of PLT ENA 2 (external 85CO input) and controls the operation of pilot logic tripping and reclosing initiation. The absence of either signal will disable the pilot system logic. The Pilot setting can be set either locally from the front panel, or via the communication interface System Type Selection ( SystType ) SystType selects the desired relaying system for the application. REL 301 has two setting choices: Non Pilot and Zone-1 Extension. REL 302 has five setting choices: Non Pilot, Zone-1 Extension, POTT (permissive overreach transfer trip), PUTT (permissive underreach transfer trip) and Blocking (directional comparison blocking) For The Pilot REL 302 Only a. 3-Term., 3- terminal line configuration setting, should be set to Yes for all three terminal line applications. b. Weakfeed (weakfeed terminal logic enable) selection should be set to Yes for all weakfeed terminal applications. c. For applications of POTT or Blocking, systems, the transient block logic is always automatically enabled and is initiated by the reverse looking units. Set Zone-3 to Reverse Dir. and Zone-3 Ø and Zone-3 G should be set to 100% of the reverse line impedance. d. The FDOGTime (FDOG trip delay timer) can be set from 0 to 15 cycles or Blocked as desired. It is recommended to set FDOGTime to 3 cycles or longer. Refer to Section for the detailed information Distance/Overcurrent Individual distance and overcurrent logic can be disabled, if required by the application by setting the unit to Disabled : a. List of units which can be disabled: Pilot Ø, Pilot G, Zone-1 Ø, Zone-1 G, Zone-2 Ø, Zone-2 G, Zone-3 Ø, Zone-3 G, Inst. Ø, Inst. G and GB Type. b. Procedure to disable the unit: Step Distance Timers Switch REL 301/302 to the setting mode (see Section 4.4.2), scrolling the function field to the desired function. Then set the unit to Disabled. a. T1 Timer can be set from 0-15 cycle delay and cannot be disabled. 2. Bold type, with small capital letters, indicates an input e.g. RESET push-button or voltage inputs. 66

85 I.L b. The T2Ø Type, T2G Type, T3Ø Time and/or T3G Time timer functions can be disabled, if desired, by setting the timer to Blocked. Timers set to Blocked, block output from the associated trip logic. For example, if T3Ø Time is set to Blocked Zone- 3 logic will not produce a trip output Zone-3 Direction Setting ( Zone-3 ) Zone-3 Ø and Zone-3 G can be selected to be forward-looking or reverse-looking by setting the Zone-3 (Zone-3 forward or reverse setting) to Forward Dir. or Reverse Dir Positive Sequence Impedance Line Angle ( Ang Pos. ) 3 Set the Positive Sequence Line Impedance Angle setting Ang Pos., to the value of the positive sequence line impedance angle. From the example data (Section 3.2), the setting would be Ang Pos. = 77 o Zero Sequence Impedance Angle ( Ang Zero ) 3 Set the Zero Sequence Impedance Angle setting ( Ang Zero ) to the value of the zero sequence line impedance angle. From the example data (Section 3.2), the setting would be Ang Zero = 73 o Zero Sequence/Positive Sequence Ratio ( Z OL /Z 1L ) 4 Set the ZOL/Z1L value based on the absolute value of the ratio of the line impedances. From the example data (Section 3.2), the setting would be ZOL/Z1L = Low Voltage Settings ( Low V ) Polarizing Settings The low voltage units are used to supervise close into fault logic and weakfeed trip logic (REL 302 only). Low V should normally be set to 40 Volts unless a higher setting is required for more sensitive applications. Settings for the directional ground overcurrent polarization is controlled by the setting of Dir Type. It has 3 selections: Zero Sequence Zero sequence voltage polarization. Negative Sequ. Negative sequence voltage polarization. Dual Polariz. Both zero sequence voltage and current polarization Overcurrent Ground Backup The overcurrent ground backup function provides seven sets of curves, which are similar to the CO curves, for backing up the ground distance protection. Four settings GB Type, GB Pickup, GBT Curve and GB Dir. must be determined for applying this function. 3. See application note under Section See application note under Section

86 INSTRUCTION MANUAL REL 301/302 a. GB Type is the ground backup curve selection. Seven sets of familiar CO curves are provided (C02,5,6,7,8,9 and 11), and are shown in Figures 2-32 through The selection is based on the application and coordination time. A selection of Disabled prevents the ground backup function from operating. b. GB Pickup is the current level setting. The setting range is 0.5 to 4.0 amperes in 0.1 steps. In general, the current level setting criteria is: (I Fmin /2) > GB Pickup > 2 x Max. Residual 3I 0 where I Fmin = Minimum ground fault current for a fault two buses away For the best sensitivity, GB Pickup should be set at 0.5 amperes, this is normally adequate for most applications. c. GBT Curve is the time delay setting of the ground backup function. As shown in Figures 3-2 through 3-8, the GBT Curve is settable in steps of one from 1 to 63. As with any time delay overcurrent function, the time delay setting must be coordinated with other overcurrent devices. d. GB Dir. is the setting for directional control selection. The ground backup function becomes a forward-directional torque control overcurrent ground function if GB Dir. is set to Yes. If GB Dir. is set to No, the overcurrent ground backup function is non-directional and will produce a trip output for faults in the forward and reverse directions. The following equation can be used to calculate the trip time for all CO curves from CO-2 through CO-1 : T (sec) = K T ( 3I 0 C) P GBT Curve 24, 000 (for 3I0 >1.5 x GB Pickup ) T (sec) = R GBT Curve ( 3I 0 1) , 000 (for 1< 3I 0 < 1.5 x GB Pickup ) Where 3I 0 = I F GB Pickup IF = Applied fault current GB Pickup = Pickup setting GBT Curve = Time curve dial setting (1 to 63). T 0, K, C, P and R are constants, and are shown in Table 3-1. Taking the CO-8 curve set as an example (see Figure 2-36), assuming that the maximum 3Io of unbalanced load is 0.2A, the minimum ground fault current for a fault two buses away is 10A, and 0.7 seconds is required for coordination with current of 20 times the GB Pickup setting, then the settings of the ground overcurrent backup function should be as shown below: 68

87 I.L /2 > GB Pickup > 2 x 0.2 set GB Pickup = 0.5 Choosing from the curves, in Figure 2-36, for 0.7 seconds at 20 times the GB Pickup setting, GBT Curve should be set to 24. Set GB Type to C0-8 and set GB Dir to YES if directional control is required. REL 301/302 offers two reset characteristics for the ground backup overcurrent function, instantaneous or time delayed. Instantaneous reset, as the name implies, means reset with no intentional time delay. Time delay reset function is a linear characteristic shown in Figure 3-9 and is intended to replicate the reset characteristics of electromechanical overcurrent relays Close-Into-Fault Trip Setting ( CIF Trip ) Set CIF Trip setting by selecting the value field CIF Trip if line side potential is used to supply the relay. See Section for special applications of close-into-fault logic Load Loss Trip Setting ( LL Trip ) Set LL Trip to YES, FDOG or NO, where: YES LL Trip trip with Z2 supervision. FDOG LL Trip with both Z2 and FDOG supervision. NO LL Trip function is not used Loss of Potential Block Setting ( LOP Blk ) Set LOP Blk to YES, if loss-of-potential block trip function is required Loss of Current Block Setting ( LOI Blk ) Set LOI Blk to YES, if loss-of-current block trip function is required Trip Alarm Setting ( Trip Alm ) Set Trip Alm to Seal-in, if trip alarm seal-in is required. The front panel, reset push-button can be used to reset the sealed alarm Remote Setting ( Rem. Set ) Set the Rem. Set to Remote Allowed if remote setting, via communications port, is required Real-Time Clock Setting With REL 301/302 in the setting mode, scroll the function field to Set Time, and change the value to Yes. Depress function push-button RAISE to display Year, Month, Day, Weekday, Hour, and Minute, and set the corresponding number via the value field. The REL 301/302 clock will start at the time the enter button is pushed while the display is showing the minute value. 69

88 INSTRUCTION MANUAL REL 301/ RECLOSE INITIATION MODE PROGRAMMING For Non-pilot and Pilot Systems 1. Select RI Type = No RI ; ØG RI ; ØØ, ØG RI ; or 3Ø, ØØ, ØØG, ØG (See Table 3-2) 2. Use one of the two (RI-1 or RI-2) 5 output contacts for the reclosing initiation circuit 3. Select one or all of the Fast RI, Zone-2 RI, and/or Zone-3 RI to Yes, depending on the application. (REL 302 set for Pilot System: For reclose initiation, following Pilot tripping, Fast RI should be set to either Pilot or Pilot/Z1/Inst I ) 5. Bold italic type indicates an output e.g. LEDs or contact output 70

89 I.L Table 3-1: TRIP TIME CONSTANTS FOR CURVES CURVE # T0 K C P R C C C C C C C Table 3-2: RECLOSING INITIATION MODE PROGRAMMING RI Type Type Of Fault Reclosing Initiation Mode No RI All Faults No reclosing initiation ØG RI ØG RI-1, RI-2 contacts close; All Other Faults no reclosing ØØ, ØG RI ØG, ØØ RI-1, RI-2 contacts close; 3Ø Faults no reclosing 3Ø, ØØ, ØØG, ØG All Faults RI-1, RI-2 contacts close Table 3-3: CURRENT TRANSFORMER SETTINGS REL 301/302 At CTYP = 5 At CTYP = 1 Z1P/Z1G/Z2P/Z2G Z3P/Z3G/PLTP/PLTG , in 0.01 W steps , in 0.05 W steps ITP/ITG , in 0.5 A steps , in 0.1 A steps IL/IOS/IOM/IM , in 0.1 A steps , in 0.02 A steps 71

90 % Overreach Resulting from DC Offset Effect On Sampling INSTRUCTION MANUAL REL 301/302 %Overreach Line Angle Figure 3-1: % Overreach Resulting from dc Offset Effect

91 I.L Figure 3-2: CO-2 Curve Characteristics REV 0 73