BE1-67 PHASE DIRECTIONAL TIME OVERCURRENT RELAY

Transcription

1 B-6 B-6 PHS RCON OVRCURRN RY he B-6 Phase irectional ime Overcurrent Relay is a microprocessorbased relay to be used to protect transmission and distribution circuits where power can flow in either direction. he relay uses quadrature voltage polarization to determine the direction of fault current flow. PPCON pages and VNGS Single- or three-phase sensing. ime overcurrent range is continuously adjustable from 0. to. nstantaneous range is adjustable from to times the time overcurrent element pickup. Polarized by line-to-line potential. ime-current characteristics are field selectable with optional switch. ime dial is adjustable in 0 incremental steps. imited Range of Operation option is available to provide additional protection against false tripping on mutually coupled lines. Optional directional or non-directional instantaneous elements. % pickup accuracy and timing repeatability. ±% timing accuracy. U recognized under Standard 8, U File #90 for units having nominal power supply inputs of Vac or less, and Vdc or less. Gost R certified #POCC US.0.B09. Five year warranty. SPCFCONS pages - 8 XRN CONNCONS pages 9 and ORRNG NFORON pages and ON NFORON NSRUCON NU Request Publication 9090 SNRS, NSONS and CCSSORS Request Bulletin S P. O. BOX 69 HGHN, NOS, U.S.. 69 PHON FX UQ-9 -

2 B-6 PPCON SCRPON he B-6 Phase irectional Overcurrent Relay is designed for the protection of transmission and distribution lines where the direction as well as the magnitude of the fault current (or power flow) are to be considered in the tripping decision. he B-6 is a directionally controlled, microprocessorbased time overcurrent relay. he directional element is polarized by the phase-to-phase quadrature voltage of the power system. hat is, the directional element monitoring phase current uses the voltage between phases B and C to determine the direction of current (or power) flow into the fault. hen, if enough current flows in the tripping direction of the relay, the relay will pickup, time out, and trip. he angle of maximum sensitivity for the relay is also adjustable to allow the directional characteristic to be matched to the line and system conditions. Figure illustrates the operation of the directional element and defines the terms that will be used in the following discussion. Figure a shows the connections to the sensing circuits for a single phase B-6. Figure b illustrates the phasor quantities monitored by the relay for a unity power factor condition and for a single-phase fault. Figure c shows the protected line on an R-X diagram. he angle alpha ( α ) in Figure b and c is the characteristic angle setting for the relay. he directional characteristic of the relay is adjustable to allow the relay to be sensitive for phase faults, and to maximize sensitivity at the characteristic angle representing a typical faulted line impedance. welve standard time-current characteristics are available to aid in the coordination of this relay with other protective devices in the system (able ). hese include seven characteristics that are standard in North merica and five that are compatible with British or C Standard requirements. n internal switch is provided to select the desired characteristic. Style Characteristic Special esignation Shape Characteristics B Short nverse Relatively short time, desirable where preservation system stability is a critical factor. B, ong nverse Provides protection for starting motors and overloads of short duration. B efinite ime Fixed time delay according to the time dial setting. Useful for sequential tripping schemes. B, oderately ccomodates moderate load changes, as nverse may occur on parallel lines where one line may occasionally have to carry both loads. B, nverse Provide additional variations of the inverse B6, 6 Very nverse characteristic, thereby allowing flexibility in B, xtremely meeting load variations, or in coordinating with nverse other relays. able f the supply to the protected portion of the system is constant, and if the magnitude of the fault current is determined primarily by the location of the fault on the line, the selection of a more inverse time characteristic may be more desirable to provide selective coordination with adjacent line protection. However, if the capacity of the supply varies significantly over a period (such as a day), a less inverse time, or even the efinite ime characteristic, may be preferred to provide smoother coordination. B C 8 HGH 9 OW 6 b. UNY POWR FCOR α FU CONON a. RPPNG RCON X V BC 6 6 PO c. PROC N α R Figure - irectional Overcurrent (Single-Phase)

3 B-6 PPCON, continued COORNON Without the ability to determine the direction of current flow, it is difficult to coordinate the settings of time overcurrent relays on lines that interconnect a series of substations. Without this capability, either the undesired tripping of adjacent lines may result, or a fault may go undetected because of the high settings required by the time overcurrent relays. SOURC B C O SOURC With directional time overcurrent relays, the settings and time delays can be decreased and the undesired tripping eliminated. Figure illustrates the use of directional overcurrent relays on a group of interconnected distribution substations fed from a common station. = BRKR = RY FU 6 6 F O SOURC B FU 6 6 C O Figure - Substations Fed From wo Sources n this example, non-directional overcurrent relays () are used to protect the lines leaving the source bus, inasmuch as there is only one source of fault current. However, the breakers at the load buses (C,,, and F) are protected by directional time overcurrent relays (6) to prevent overtripping in the event of a fault. his will remove the faulted line and retain service to the connected loads. = BRKR = RY 6 6 F O n the case where two sources of power can supply fault current, as shown in Figure, directional overcurrent relays will need to be applied to each end of the protected lines to prevent undesired tripping. Figure - ll Substations Fed From One Station SPCFCONS FUNCON SCRPON he specifications on these pages define the features and options that can be combined to exactly satisfy an application requirement. he block diagram (Figure ) illustrates how the various standard features, as well as the options, function together. NPUS Current Sensing Current sensing can be selected as either single-phase or three-phase as determined by the style chart. ach current sensing transformer of the relay ( per phase) receives the output from the ( nominal) secondary of a standard system current transformer. ach current sensing input has a sensing range of 0. to.0. he continuous current capability is rated at. he current sensing input burden is less than 0.0 per input. wo current sensing frequencies are offered: Hz or Hz. he maximum -second current rating is x the maximum tap current selected, or 0, whichever is less. For ratings other than those specified by the time curves, the rating is calculated as follows: = ( X tap value or 0, whichever is less) where = aximum current = ime of current flow in seconds Voltage Sensing he voltage sensing input transformers receive their input from Volt nominal secondary, standard system voltage transformers.

4 B-6 SPCFCONS, continued NCORS OVRCURRN N U- PXOR NHB NG Ø ØB ØC Ø ØB ØC O C S B C P SC P C NS J CURV SCOR SWCH / CONVRR & V COR O U P U Ø ØB ØC N RGS V CHRCRSC PHS NG JUSN RGON OF OPRON JUSN CRO- PROCSSOR NOR /S SWCH N R F C RG RP O P S V B RCON N RG NS RP V C PUSH-O-NRGZ OUPUS (OPON -C) POWR OPRNG POWR POWR SUPPY POWR SUPPY SNSOR O NRN CRCURY POWR SUPPY SUS Figure - Functional Block iagram ach voltage sensing input has a continuous voltage rating of Vac, and a sensing input burden greater than K ohms at Vac. Proper directional decisions are assured when the current applied to the relay exceeds % of P value and the voltage exceeds.0 Vac at the setting of the characteristic angle. POWR SUPPY One of five power supply types may be selected to provide internal operating power. hey are described in able. nput Voltage ype Nominal Range Burden at Nominal J (mid range) Vdc to Vdc. W Vac 90 to Vac.8 V K (mid range) 8 Vdc to Vdc.9 W (low range) Vdc to Vdc*. W Y (mid range) 8 Vdc or to Vdc.9 W Vdc to Vdc. W Z (high range) Vdc 68 to Vdc. W Vac 90 to 0 Vac.6 V * ype power supply may require Vdc to begin operation. Once operating, the voltage may be reduced to Vdc. able CURRN SNSNG NPU he B-6 Phase irectional ime Overcurrent Relay incorporates two basic measuring elements, the directional unit and overcurrent unit. he overcurrent tap is selected by a -position, rotary type, P SC switch. he available taps are shown in able. ow range or high range is determined by selection of the input connections. (See Figures 9b and b). he P C control sets the overcurrent pickup point between the discrete positions of the P SC switch to provide continuous pickup adjustability over the entire sensing input range (0. to.0). fully CW adjustment puts pickup within ±% of the indicated P SC setting. Pickup repeatability is ±%. RCON UN he directional unit determines the direction of the current by analyzing the angular relationship between the operating current and a reference (polarizing) voltage. he operating current is the particular phase current under consideration and the polarizing voltage is the appropriate quadrature phase-to-phase voltage. etermination of direction requires less than cycle. P Current Sensing erminal Range P Selector Single Phase Plate B C F G H J Phase B C HGH , 8,,, 8 OW , 9,, 6, 8 able - Sensing nput Ranges

5 B-6 SPCFCONS, continued = O CURRN UNY POWR FCOR z = N CURRN FOR FU PNC Z RP Z α = CHRCRSC NG B RP α α B NO RP V V BC a. Standard Range of Operation Figure - Characteristic ngle (lpha) b. imited Region of Operation he directional unit is front-panel adjustable by the CHRCRSC PHS NG control and the (optional) RGON OF OPRON adjustment. Both are described below. Characteristic ngle he CHRCRSC NG control determines the characteristic angle (α) of Figure. his causes the characteristic of the directional unit to be rotated so that maximum sensitivity can match the impedance angle of the protected line. he tripping characteristic of the relay is then defined by a line that is normal to α. (he slight bow in the trip/no trip boundary at the origin is caused by the minimum sensitivity of the directional element: 0.0 and.0v.) he CHRCRSC NG control may be a potentiometer (Options -, -, -, and -6) or a -position switch (Options - and -). Once established, angles are repeatable to within ± at nominal frequency. he potentiometer control has a range of When the control is a switch, the four discrete settings are,,, and. When the phase relationship between current and voltage does not fall within the parameters of the directional element, an inhibit signal illuminates the appropriate PHS NHB indicator and prevents operation of the time overcurrent function. his signal also inhibits operation of the (optional) directional instantaneous overcurrent element. (nhibit signals are generated independently for each sensed phase.) imited Region of Operation (Option) RP imed trip is a standard feature of the relay. Pickup is determined by the P SC and the P C controls. When the overcurrent condition exceeds the pre-selected pickup point and the directional unit has removed its inhibit signal (indicating that direction is proper for tripping), timing is initiated. f these conditions persist for sufficient time, time-out will occur and the final output will energize. Various timing characteristics are available and are defined by Figures through 8. ndividual curves of the designated set are selected by use of the front-panel time dial. he time dial is adjustable from to in increments of 0. iming accuracy is within ±% or ms, whichever is greater, of the time indicated by the characteristic curve for any combination of time dial and pickup setting. imings are repeatable to within ±% or ms, whichever is greater. NSNNOUS RP (Option - or -) he instantaneous pickup point is front-panel adjustable from to times the selected pickup setting for timed trip. When the overcurrent condition exceeds the pickup point by the selected multiple, the instantaneous output relay energizes, assuming that:. he instantaneous option is non-directional (i.e., Option -); or. he instantaneous option is directional (Option -) and the sensed current is in the trip direction. Figure a indicates the region in which tripping is allowed: the shaded half-plane bounded by a line normal to Z at the origin. he tripping region may be reduced (as illustrated in Figure b) by means of the front panel RGON OF OPRON control. his control is continuously adjustable (with reference to angle B) from ± to ±90.

6 B-6 SPCFCONS, continued Pickup for the instantaneous element is accurate to within ±% of the expected value. ropout is greater than 9% of the established pickup level. ypical response time is shown in Figure 6. 6 O COS OUPU CONCS (SCONS) UPS OF PCKUP Figure 6 - ypical nstantaneous Function Response ime CROPROCSSOR he microprocessor is ultimately responsible for all timing functions, control functions, magnitude comparisons, and decision making within the relay. he B-6 utilizes an 8-bit COS microprocessor to accomplish these functions. POWR SUPPY SUS OUPU (OPON) normally closed (NC) output contact is provided to indicate the failure of the relay power supply. Under normal operating conditions, and with power applied to the relay, this output relay is energized and its contact is open. f the power supply ceases to provide proper operating voltages to the internal circuitry, the output relay de-energizes and the contact closes. Removing the relay from its case will also give a closed (or out-of-service) indication. OUPUS Output tripping contacts are provided for each function incorporated in the relay (i.e. ime rip and, if selected, nstantaneous rip) and may be configured for normally open (NO) or normally closed (NC) operation. ll output contacts are rated as follows: Resistive Vac ake, break, and carry ac continuously. Vdc ake and carry dc for 0. s, carry dc continuously, break 0. dc. 0 Vdc ake and carry dc for 0. s, carry dc continuously, break 0. dc. nductive Vac, Vdc, Vdc Break 0. (/R = 0.0). RGS (OPON) lectronically latched target indicators are optionally available to indicate that the respective output has tripped, and to further indicate (in multi-phase units) which particular phase or phases are involved. argets may be either internally operated or current operated. Current operated targets employ a 0. ohm current relay and require a minimum of 0. flowing in the trip circuit to actuate. argets for this relay are further classified as either element targets or function targets. ll element targets are internally operated and indicate the particular phase or phases causing the trip. Function targets, on the other hand, are associated with the primary tripping functions of relay. ll function targets within a specific unit are of the same type, either all current operated or all internally operated. PUSH-O-NRGZ-OUPU PUSHBUONS ccessible with a thin non-conducting rod through the front panel, push-to-energize pushbuttons are available to energize each output relay for testing the external control/ protective system wiring. SURG WHSN CPBY Qualified to NS/ C and C.90a-9 Surge Withstand Capability est; C - mpulse est and ielectric est. CHNC Operating emperature - C (- F) to +0 C (+8 F). Storage emperature -6 C (-8 C) to +0 C (+ F). Weight 8 pounds maximum. Case Size. (Case and mounting dimensions are defined in Bulletin S) Shock n standard tests, the relay has withstood g in each of three mutually perpendicular axes without structural damage or degradation of performance. Vibration n standard tests, the relay has withstood g in each of three mutually perpendicular axes, swept over the range of to 0 Hz for a total of six sweeps, minutes each sweep, without structural damage or degradation of performance.

7 B-6 SPCFCONS, continued OVRCURRN CHRCRSC CURVS ime in Seconds ime in Seconds ime in Seconds ultiples of Pickup Current ultiples of Pickup Current ultiples of Pickup Current Figure - B: Short nverse Figure 8 - B: ong nverse Figure 9 - B: efinite ime ime in Seconds ime in Seconds.0.0 ime in Seconds ultiples of Pickup Current ultiples of Pickup Current ultiples of Pickup Current Figure - B: oderately nverse Figure - B: nverse Figure - B6: Very nverse

8 B-6 SPCFCONS, continued OVRCURRN CHRCRSC CURVS (continued) ime n Seconds ime in Seconds ime in Seconds ultiples of Pickup Current ultiples of Pickup Current ultiples of Pickup Current Figure - B: xtremely nverse Figure - : ong nverse BRSH SNR CURV Figure - : nverse BRSH SNR CURV ime in Seconds.0 ime in Seconds ime in Seconds ultiples of Pickup Setting ultiples of Pickup Current ultiples of Pickup Setting Figure 6 - : nverse BRSH SNR CURV Figure - 6: Very nverse BRSH SNR CURV Figure 8 - : xtremely nverse BRSH SNR CURV 8

9 B-6 CONNCONS a. b. Figure 9 - Single Phase Connections 9

10 B-6 CONNCONS, continued a. b. Figure - hree Phase Connections

11 B-6 O NUBR B-6, Phase irectional ime Overcurrent Relay SY NUBR ORRNG Output () Normally open output contact iming (Z) Switch selectable timing characteristics he style number appears on the front panel, drawout cradle, and inside the case assembly. his style number is an alphanumeric combination of characters identifying the features included in a particular unit. he sample style number below illustrates the manner in which the various features are designated. he Style Number dentification Chart (page ) defines each of the options and characteristics available for this device. SP SY NUBR: B-ZJ-BCF he style number above describes a B-6, Phase irectional ime Overcurrent Relay having the following features. Sensing nput ype (B) hree-phase Sensing nput Range () 0. to.0, Hz Power Supply (J) Vdc/ Vac nominal input power supply arget (B) Current operated targets Option () One directional instantaneous overcurrent element Option (C) Push-to-energize-output pushbuttons Option () Continuously adjustable characteristic angle Option (F) Semi-flush mounting NO: he description of a complete relay must include both the model number and the style number as shown below. B-6 B Z J B C F SNSNG NPU YP SNSNG NPU RNG OUPU NG POWR SUPPY OPON OPON OPON OPON RG HOW O ORR SNR CCSSORS esignate the model number followed by the complete style number. he following accessories are available for the B-6, Phase irectional ime Overcurrent Relay. est Plug B-6 Style No. Complete the style number by selecting one feature from each column of the Style Number dentification Chart and entering its designation letter or number into the appropriate square. (wo squares are used to indicate time delay characteristics.) ll squares must be completed. o allow testing of the relay without removing system wiring, order two test plugs, Basler lectric part number 09.

12 B-6 SY NUBR NFCON CHR Route, Box 69, Highland, llinois U.S.. 69 el Fax info@basler.com P... es Pins, 69 Wasselonne Cedex FRNC el Fax beifrance@basler.com No. 9 Heshun Road oufeng istrict (N), Suzhou ndustrial Park,, Suzhou, P.R.China el +86(0) Fax +86(0) beichina@basler.com Ubi venue #0-0 Singapore 89 el Fax beisingapore@basler.com