Application and Commissioning Manual for Numerical Over & Under Voltage Protection Relays Type MVT181 CONTENTS PAGE APPLICATION 2-7 INSTALLATION 8-16

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2 Application and Commissioning Manual for Numerical Over & Under Voltage Protection Relays Type MVT181 CONTENTS PAGE APPLICATION 2-7 INSTALLATION 8-16 COMMISSIONING WIRING DIAGRAM 23

3 1. INTRODUCTION APPLICATION The type MVT181 numeric under voltage / over voltage relay combines the power and flexibility of microprocessor technology.two protection elements, multiple characteristics and TRUE RMS measurements are available. Moreover, supervisory components and self monitoring features give high confidence of serviceability. 2. APPLICATION MVT181 is a numerical TRUE RMS single pole over voltage and under voltage relay, which can be used to protect the power system during over voltage and under voltage conditions. Though the relay is generally applicable for any under and over voltage application, this relay is best suited for capacitor bank protection as this is having an in-built timer function. A time delay function is necessary in a capacitor bank protection to allow the capacitor bank to discharge to a safer level, before reconnecting the same to the system. Otherwise there will be a danger to the breaker and the capacitor bank, while the capacitor charged to a negative peak is connected to the system voltage when it is in positive peak. 3. DESCRIPTION 3.1. Two Elements MVT181 is a numerical TRUE RMS single pole relay consists of two elements. Each element can be selected for under voltage function or over voltage function or switched off. The characteristics setting, voltage setting and time multiplier setting are independently settable for each element and the voltage setting is in terms of voltage. Hence this relay can also be used as a two stage under voltage / two stage over voltage protection. One stage U/V & One stage O/V Multiple Characteristics Over voltage function is provided with four operating characteristics and under voltage function has two operating characteristics Over Voltage Characteristics a) Definite time lag b) Long time Inverse Characteristic t = 40 * T M [ (V/V ) - 1] S 2

4 c) Extremely Inverse 1 (EI 1) 5 * T M t = 2 2 [ (V/V S) - 1 ] d) Extremely inverse 2 (EI 2) This curve is based on ANSI / IEEE C37.99 and IEC The time delay for various multiples of over voltage is given below for TMS 1.0. Multiples of Setting Voltage Operating time (Sec) Where t = Operating Time in Secs V = Fault Voltage V s = Setting voltage T M = Time Multiplier Setting 3.4. Under Voltage Characteristics a) Definite Time Lag b) Extremely Inverse 1 (EI 1) 5 * T M t = 2 [1 (V/V ) ] 3.5. Timer S 2 The relay is provided with two status inputs, one of which is to be connected across the circuit breaker auxiliary contact 52a. From this the circuit breaker closed or opened condition is found out. This information is used to introduce a time delay between successive switching of the capacitor banks which allows the capacitor bank to discharge to a safer value after disconnected from a live network. This timer function is a settable one and its output (N/O) contact is used in the closing circuit of the circuit breaker. The completion of the time delay is also indicated by 'TIMER' LED in the front fascia. In addition the same status input can be used for trip circuit supervision also. During the under voltage and over voltage applications this timer function can be disabled or used as an independent timer function Trip Circuit Supervision Pre-closing and post closing supervision of the trip circuit and trip supply is possible with this relay. A low value of DC current is passed through the entire trip circuit to monitor the trip coil, its auxiliary 3

5 switch and the associated wiring. One of the status input is connected across the tripping contact and another status input is connected across the 52a contact (auxiliary contact of the circuit breaker) in series with the trip coil. During trip circuit fail condition the monitoring current flow ceases and the energized status input drops off and the relay gives a contact output to indicate this condition. In addition to this contact On LED is provided in the front fascia to indicate the 'T.C.FAIL'. A time delay of approximately 400 m.sec has been given to avoid false trip circuit fail indication at the time of normal tripping. Thus trip circuit supervision is the integral part of the relay. If this function is not required the same can be put off in the setting menu. 4. TECHNICAL INFORMATION 4.1. Rating upto 230 V AC (same terminals) Frequency 50 Hz Nominal 4.2. Auxiliary Supply Nominal Voltage Voltage Range 24 / 30 / 48 / 110V DC V DC 48/110/220 V DC or 110V AC V DC 4.3. DC Status Input Nominal Voltage Voltage Range 24 / 30 DC V DC * - For status input nominal voltage greater than 30V, external dropper resistors should be used Settings Element Setting Element 1: UV, OV or OFF Element 2 : UV, OV or OFF Voltage Setting 5V to 275V in steps of 1V Characteristic Setting When the element is set as Under Voltage a) Definite time lag (DTL) characteristics 0 to 200 sec in steps of 0.1 sec b) Extremely inverse 1 (EI 1) characteristics t = 5 * T M 2 2 [1 (V/V s) ] 4

6 When the element is set as Over Voltage a) Definite time lag characteristics 0 to 200 sec in steps of 0.1 sec b) Long Time Inverse characteristics t = 40 * T M [ (V/V ) - 1 ] s c) Extremely Inverse 1 (EI 1) characteristics 5 * T M t = [ (V/V ) 1 ] 2 2 s d) Extremely Inverse 2 (EI 1) characteristics This is based on ANSI / IEEE C37-99 and IEC The standard time delay for various multiples of over voltage is given as under for time multiplier setting of 1.0. Multiples of Setting Voltage Operating time (Secs) Where t V V T s M = Operating Time in Secs = Fault Voltage = Setting voltage = Time Multiplier Setting Time Multiplier Setting to 1.0 in steps of ( for all inverse characteristics) Time setting if DTL is selected 0 to 200 Secs in steps of 0.1 Sec Timer For CB Closing Interlock 0 to 600 secs in steps of 1 sec or OFF Trip Circuit Supervision On or OFF 5

7 4.5. Accuracy Starter pick-up (UV) 96% of V s +3% Starter drop-off (UV) <106% of V s Starter pickup (OV) 104% of V +3% ( except for EI 2) s Starter Pickup (OV) 108% of V s +3% (EI 2) Starter drop-off (OV) >94% of V s Inverse operating time +5% or 35 m.sec Voltage measurement +3% DTL operating time +1% or 35 m.sec 4.6. Output Contact Rating Carry continuously Make & Carry Break 5A AC rms or DC 20A AC or DC for 0.2 Sec 50W DC with a max. of 300V or 5A DC L/R <40mS 4.7. Indication Green LED Protection Healthy Yellow LED Starter Indication Red LED Trip Indication Red LED Trip circuit fail Red LED Completion of timer 7 segment Display Settings / Trip indication 4.8. Burden AC < 0.015VA at 63.5V < 0.035VA at 110V < 0.15VA at 230V DC (Quiescent) 5W 5. ENVIRONMENTAL 5.1. Temperature IEC /2 Operating Range -10 C to + 55 C Storage Range -25 C to + 70 C 5.2. Humidity IEC days at 40 C and 93% RH 6

8 5.3. Transient Over voltage IEC kV,1.2/50µS, 0.5j between all terminals and earth or between any two terminals without damage or flashover Insulation IEC kV rms for 1 min between all terminals and earth 2.0kV rms for 1 min between independent circuits 1.0kV rms for 1 min across normally open contacts 5.5. High Frequency Disturbance IEC , Class III Variation 2.5kV Common (Longitudinal) mode <3% 1.0kV series (Transverse) mode <3% 5.6. Electrostatic Discharge IEC , Class III Variation 6kV Contact Discharge <5% 8kV Air Discharge <5% 5.7. Radio Frequency Interference IEC , Class III Variation 20MHz to 1000 MHz, 10V/m <3% 5.8. Fast Transient IEC , Class IV Variation 4kV, 5/50 ns, 2.5kHz repetitive <5% 5.9. Vibration (Sinusoidal) IEC , Class Shock & Bump IEC , Class 1 6. CUTOUT DETAILS 151 x 151mm (2/3 Vedette draw out case) 7

9 1. UNPACKING INSTALLATION On receipt, remove the relay from the carton box in which it was received and inspect it for obvious damage. It is recommended that the relay is not removed from the relay case. To prevent the possible ingress of dirt, the sealed polythene bag should not be opened until the relay is to be used. If damage has been sustained, please inform Easun Reyrolle Ltd., for necessary action. 2. STORAGE When the relay is not required for immediate use, it should be returned to its original carton and stored in a clean dry place. 3. HANDLING The relay's electronic circuits are protected from damage by static discharge when the relay is housed in its case. When relay is withdrawn from the case, static handling procedures should be observed: Before removing the relay from its case the operator must first ensure that he is at the same potential as the relay, by touching the case. The relay must not be handled by any of the relay terminals at the rear of the chassis. Ensure that anyone else handling the relay is at the same potential. As there are no user serviceable parts and adjustable user settings inside the relay, there should be no requirement to remove any modules from the chassis. If any modules are removed or tampered with, then the guarantee will be invalidated. 4. MOUNTING Mount the relay using 2 nos. mounting straps and 1no earth strap. Ensure that an earth wire is connected to the earth strap from the earth terminal 23. Terminal 23 should be directly connected to the system ground. Only settings or trip details can be accessed via the pushbuttons when the cover is fitted. To change the settings the front cover has to be removed. Sealing arrangement is provided in one of the four knurling screws fitted on the cover. Sealing can be done using a sealing wire. Thus mechanical interlock is provided to avoid unauthorized setting change. 5. EQUIPMENT 5.1. Voltage Selection MVT 181 relay is suitable for up to 230V A.C. applications 8

10 5.2. Status Input Two status inputs ( 5& 6, 7 & 8) have to be wired for trip circuit fail application/ capacitor discharge timer interlock. One status input (7&8) can be used for only capacitor discharge timer interlock. The status input external resistors are connected as per the typical wiring diagram shown (Fig 4) and the resistors value is given in the following table. Nominal Voltage Operating Range R1,R2,R3 & R4 Relay terminal nos. 48V DC 1.36 to 60V DC 1.0K ohms/9w 110V DC 2.88 to 135V DC 3.9K ohms/9w 5 & 6, 7 & V DC to 280V DC 8.2K ohms/9w 5.3. Human Machine Interface (HMI) Table 1 shows input external resistors The user friendly HMI provided on the front panel has following features: 1. Six digit, 7 segment LED display (First two digits are Red colour and other four digits are Green colour). first two digits (Red) displays the main menu or type Element operated when selected for Setting mode or Trip indication respectively. Remaining four digits (Green) displays Sub menu or "Trip" indication respectively. 2. Green LED - Protection healthy indication 3. Yellow LED(STARTER) - Starter indication 4. Red LED (TRIP) - Trip indication 5. Red LED (in Key) - Sub Menu 6. Red LED (T.C.FAIL) - Trip circuit Fail indication 7. Red LED (TIMER) - Timer operated indication 8. Key - Up scrolling 9. Key - Down scrolling 10. Key - Sub menu 11. x Key - Enter / Reset / Cancel / To check Version 9

11 5.4. How to operate HMI Remove the front cover by unscrewing the four knurling screws. Apply DC supply. Terminals 22,24 and 23 are for positive, negative and earth respectively as per relay rating. When the relay powers up it takes few seconds to complete the self-test routing. Ensure Protection Healthy LED (Green) is ON and busy indication appears on the LED display unit. Wait until the busy indication goes off. Press or key nnut I8 is displayed nnut I8 Represents MVT 181 relay Press key repeatedly scrolls down the Factory setting Main menu in the following order on the display. El off - Element 1 is OFF ( El is Main menu and off is sub menu) E2 off - Element 2 is OFF td l0 - Timer setting is 10Secs tc off - Trip circuit supervision is OFF 6. SETTING INSTRUCTIONS 6.1. Voltage Function Selection ELEMENT 1 Pressing key repeatedly to get El off Main menu, press Submenu Key, LED in the Key Lit to indicate that the Sub menu is activated off - voltage function is OFF undr - Under voltage ** ouer - Over voltage By pressing or key choose the desired voltage function(under voltage or Over voltage or OFF) for Element 1 and press key. Now the Submenu LED goes OFF and the Main menu appears on the LED display ELEMENT 2 Pressing key repeatedly to get E2 off Main menu, press Submenu Key, LED in the Key Lit to indicate that the Sub menu is activated. 10

12 off - voltage function is OFF undr - Under voltage ** ouer - Over voltage By pressing or key choose the desired voltage function((under voltage or Over voltage or OFF) for Element 2 and press key. Now the Submenu LED goes OFF and the Main menu appears on the LED display ** Ensure AC voltage input more than the setting is given to the relay terminal number 11 &12 before selecting Under voltage function to avoid unnecessary tripping Voltage Settings Setting Range : 5V to 275V in steps of 1V ( For Element 1 - over voltage /under voltage and Element 2 - over voltage /under voltage) Pressing key Ul l00 (represents voltage for Element 1 is 100V) display will appear if Element 1 voltage function is chosen Pressing key U2 l00 (represents voltage for Element 2 is 100V) display will appear if Element 2 voltage function is chosen The voltage function can be select to OFF. If any voltage function is chosen to off that particular voltage main menu will not appear in display ELEMENT 1 Pressing key repeatedly and Ul l00 Main menu (represents voltage for Element 1 has been set to 100V), press key (Submenu LED On) to get the Sub menu. Pressing the or key, changes the voltage setting in 1V increment or decrement. Upon selecting the desired setting, once again press the key (Sub menu LED goes OFF) to return to the main menu ELEMENT 2 Pressing key repeatedly and U2 l00 Main menu (represents voltage for Element 1 has been set to 100V), press key (Submenu LED On) to get the Sub menu. Pressing the or key, changes the voltage setting in 1V increment or decrement. Upon selecting the desired setting, once again press the key (Sub menu LED goes OFF) to return to the main menu Select Characteristics ELEMENT 1 a) For Under Voltage 11

13 From Cl Ell Main menu, press Submenu Key, LED in the Key Lit to indicate that the Sub menu is activated. Pressing key repeatedly the Sub menu will scroll down in the following order on the display Ell - Extremely Inverse 1(EI1) d tl - Definite Time Lag (DTL) By pressing or key choose the desired characteristic and press Key. Now the Submenu LED goes OFF and the Main menu appears on the LED display. b) For Over Voltage From C2 Ell Main menu, press Submenu Key, LED in the Key Lit to indicate that the Sub menu is activated. Pressing key repeatedly the Sub menu will scroll down in the following order on the display Ell - Extremely Inverse 1(EI1) El2 - Extremely Inverse 2(EI2) Ltl - Long Time Inverse (LTI) dtl - Definite Time Lag (DTL) ELEMENT 2 a) For Under Voltage From CI Ell Main menu, press Submenu Key, LED in the Key Lit to indicate that the Sub menu is activated. Pressing key repeatedly the Sub menu will scroll down in the following order on the display Ell - Extremely Inverse 1(EI1) dtl - Definite Time Lag (DTL) By pressing or key choose the desired characteristic and press Key. Now the Submenu LED goes OFF and the Main menu appears on the LED display. b) For Over Voltage From C2 Ell Main menu, press Submenu Key, LED in the Key Lit to indicate that the Sub menu is activated. 12

14 Pressing key repeatedly the Sub menu will scroll down in the following order on the display Ell - Extremely Inverse 1(EI1) El2 - Extremely Inverse 2(EI2) Ltl - Long Time Inverse (LTI) dtl - Definite Time Lag (DTL) By pressing or key choose the desired characteristic and press key. Now the Submenu LED goes OFF and the Main menu appears on the LED display Time Setting If characteristic is selected as Definite Time Lag, the Time setting range is, 0.0 Sec to Sec in steps of 0.1Sec. If characteristic is selected as Inverse curve, the Time Multiplier setting range is to in steps of ELEMENT 1 a) For Inverse Characteristics Pressing key repeatedly and get ti I.000 Main menu(represents time multiplier for Element 1 has been set to 1.000), press key (Submenu LED On) to get the Sub menu. Pressing the or key, changes the time setting by increment or decrement. Upon selecting the desired setting, once again press the key (Sub menu LED goes OFF) to return to the main menu. b) For Definite Time Lag Pressing key repeatedly and get ti 3.0 Main menu (represents time setting for Element 1 has been set to 3.0sec), press key (Submenu LED On) to get the Sub menu. Pressing the or key, changes the time setting by 0.1sec increment or decrement. Upon selecting the desired setting, once again press the key (Sub menu LED goes OFF) to return to the main menu ELEMENT 2 a) Inverse Characteristics Pressing key repeatedly and get t2 I.000 Main menu(represents time multiplier for Element 2 has been set to 1.000), press key (Submenu LED On) to get the Sub menu. Pressing the or key, changes the time setting by increment or decrement. Upon selecting the desired setting, once again press the key (Sub menu LED goes OFF) to return to the main menu. 13

15 b) Definite Time Lag Pressing key repeatedly and get t2 3.0 Main menu(represents time setting for Element 2 has been set to 3.0sec), press key (Submenu LED On) to get the Sub menu. Pressing the or key, changes the time setting by 0.1sec increment or decrement. Upon selecting the desired setting, once again press the key (Sub menu LED goes OFF) to return to the main menu Time selection for TIMER (Circuit Breaker close prevention for capacitor) Setting range: 0 to 600 Secs in steps of 1Sec or OFF Pressing key repeatedly and get td I0 Main menu(represents time delay for TIMER has been chosen to 10Sec), press key (Submenu LED On) to get the Sub menu. Pressing the or key, changes the Timer setting in 1Sec increment or decrement. Upon selecting the desired setting, once again press the key (Sub menu LED goes OFF) to return to the main menu Trip circuit Supervision Pressing key repeatedly and get tc off Main menu ( represents Trip Circuit Supervision function is OFF), press key (Submenu LED On) to get the Sub menu. Press key on - Represents trip circuit supervision is ON select either Trip circuit is ON or OFF, once again press the key (Sub menu LED goes OFF) to return to the main menu Acceptance of Settings (ENTER) For the relay to accept the above setting changes press X key once, now the display goes off and the settings are updated. By pressing any key again nnut I8 Indication will appear Ensure all the chosen settings. In case of any changes required use Sub menu key and then do the changes and finally press enter X key once. 7. TO CHECK THE RELAY VERSION Press X key four times, example of relay version display is as follows : I8I. 001 Represent M V T 181 relay version 1 To get back the main menu, press or key. ENSURE TO PRESS X TO ACCEPT THE CHANGES 8. TO CANCEL SETTING WHILE CHANGING (CANCEL) While the particular setting is being changed (using or key) with Submenu LED ON, pressing X key, the original setting is restored 14

16 9. TRIP INDICATION AND RESETTING OF TRIP INDICATION (RESET) When the relay operates, "TRIP" LED indicates tripping. To find which element operated press or key. There is possibility for the following display after the trip, EI utrp E2 utrp EI otrp E2 otrp Indicates Element 1 is operated due to under voltage Indicates Element 2 is operated due to under voltage Indicates Element 1 is operated due to over voltage Indicates Element 2 is operated due to over voltage Suppose Element 1 has started but not initiated trip, but Element 2 is tripped then pressing any arrow key EI.o.5tr (Indicates Element 1 is started due to Over voltage) E2.o.trp (Indicates Element 2 is tripped due to Over voltage) will appear alternatively for each pressing of the key. Once the fault is cleared, press X key twice to reset the trip indication. The trip indication will be retained in Non - volatile memory during auxiliary DC power supply failure. 10. TRIP CIRCUIT SUPERVISION INDICATION When the Status inputs are used for Trip Circuit Supervision and when the Trip Circuit Supervision function is made to "ON", upon failure of Trip Circuit, the "T.C.FAIL" LED will appear. On restoration of the Trip Circuit back to healthy condition, this LED will disappear automatically. 11. TIMER INDICATION The TIMER function is dependent on the Status input, if time delay is selected in the TIMER function and after completion of time delay "TIMER" LED will appear in the relay. This is self-reset in nature and goes off if the Status input is off. 12. SPECIAL INSTRUCTION In case of accidental setting of under voltage without giving AC input voltage (terminal 11 &12) and X key is pressed, the relay will trip an account of no voltage present. The display EI utrp (for Element 1) or E2utrp (for Element 2) will appear and "STARTER", "TRIP" LED's will glow. To restore back under this condition follow the special resetting procedures mentioned below, Press arrow key for about 30 to 50 seconds continuously. nnut I8 Display will appear. 15

17 Press key you will see the following settings EI off - Element 1 is OFF E2 off - Element 2 is OFF td off - Timer setting is OFF tc off - Trip circuit supervision is OFF Press the X key once, "STARTER" LED will disappear Now use the normal technique of going to Submenu and changing the required setting. Ensure you correctly set the relay Press X key once and put off the auxiliary voltage supply to the relay Apply A.C input voltage to terminal 11 & 12 if required (if you have selected under voltage) then on the auxiliary voltage supply, now "TRIP" LED will disappear. In case of accidental setting of over voltage less than or equal to under voltage setting also special resetting technique of the above to be used. 16

18 COMMISSIONING 1. REQUIRED TEST EQUIPMENTS 500V insulation test sets. Variable secondary injection voltage source rated 230V a.c. or greater. Time interval meter Primary injection equipment A DC supply with a nominal voltage within the working range of the relays DC auxiliary supply ratings 2. INSPECTION Ensure that all connections are tight and in accordance with the relay wiring diagram and the scheme diagram. Check if the relay is correctly programmed and the relay is fully inserted into the case. 3. APPLYING SETTINGS The relay settings for the particular application should be applied before any secondary testing is started. 4. PRECAUTIONS Before testing commences, the equipment should be isolated from the voltage transformers. The tripping and alarm circuits should also be isolated, where practical. Also, ensure that trip links are removed. Ensure that correct DC auxiliary voltage and polarity is applied. See the relevant scheme diagrams for the relay connections. 5. TESTS 5.1. Insulation Connect together all relay PT terminals and measure the insulation resistance between these terminals and all the other relay terminals connected together to earth. Connect together the terminals of the DC auxiliary supply (only +ve and -ve) and measure the insulation resistance between these terminals and all other terminals connected together to earth. Connect together all the output relay terminals and measure the insulation resistance between these terminals and all other terminals connected together to earth. A minimum value of 2. 5 to 3 meg ohms can be considered as satisfactory value Secondary Injection Select the relay configuration and settings for the application. 17

19 PICK UP AND RESET a) Over Voltage Characteristic The test checks accuracy of the voltage settings for the relay over voltage and under voltage characteristics. Apply single-phase voltage into the voltage inputs. Slowly increase the voltage until the starter LED (yellow) operates and record the pick up voltage in Table 2. Reduce the voltage until the LED goes off and record this as the reset level. Check that the pick up voltage level are measured within 104% + 3% (except EI 2 characteristic) of the applied setting. Check that the reset levels are > 94% of the setting. CHARAC- TERISTIC PICK-UP SETTING MEASURED PICK-UP PICK-UP ERROR MEASURED RESET RESET ERROR Over voltage TABLE 2 b) Under Voltage Characteristic Apply single phase voltage, higher than the setting level into the voltage inputs. Slowly reduce the voltage until the starter LED ( yellow) operates and record the pick up voltage in Table 3. Increase the voltage until the LED goes off and record this as the reset level. Check the pick up voltage level are measured with in 96% ± 3% of applied voltage setting and check the reset level 106% of voltage setting. CHARAC- TERISTIC PICK-UP SETTING MEASURED PICK-UP PICK-UP ERROR MEASURED RESET RESET ERROR under voltage TABLE DTL/IDMTL CHARACTERISTICS This test checks the accuracy of the main time delay characteristics ( DTL/IDMTL ). Select the relay voltage setting characteristics and time multiplier settings as required and then inject a level of voltage which is a multiple of the relay setting. A time interval meter should be connected to the correct output contact terminals. The timer should be started by the source "ON" switch for O/V and OFF switch for U/V and stopped by the relay trip contacts. A secondary injection timing test circuit is illustrated in Fig. 1. The secondary injection test equipment should be made 'OFF', once the relay contact is closed Table 4 & 6 shows theoretical value of each characteristic with time multiplier set to Record the actual results in Table 5 & 7 for both over voltage and under voltage characteristic and check that the measured times are within + 5% or + 35 m. sec of theoretical value. 18

20 a) Over voltage CURVE 1.2 xvs 1.7 xvs 2.2 xvs DTL * * * LTI EI EI TABLE 4 * USER SETTING Characteristic Curve 1.2 x Vs 1.7 x Vs 2.2 x Vs Over voltage DTL,LTI,EI 1 & EI 2 Delay Error (±5%) Delay Error (±5%) Delay Error (±5%) TABLE 5 b) Under voltage CURVE 0.05 xvs 0.5 xvs 0.95 xvs DTL * * * EI TABLE 6 * USER SETTING Characteristic Curve Under voltage DTL & EI xVs 0.5xVs 0.95xVs Delay Error (±5%) Delay Error (±5%) Delay Error (±5%) TABLE 7 19

21 TIMER FOR CLOSE PREVENTION When enabled test the timer as shown in Fig TRIP CIRCUIT FAIL When enabled test the trip circuit fail both in breaker ON & OFF condition by Removing the trip circuit wiring OUTPUT CONTACTS COMBINATION a) Starter 1 N/O This contact to be used while testing the pick up and reset value of the relay. b) Common trip & alarm for U/V AND O/V 2 N/O contacts These contacts to be used while testing the under voltage and over voltage characteristics. c) U/V or O/V Element 1 operated 1 N/O contact This contact to be used while testing the U/V or O/V characteristic of element 1. d) U/V or O/V Element 2 operated 1 N/O contact This contact to be used while testing the U/V or O/V characteristic of element 2. e) Protection Healthy - 1 N/C contact This contact indicates the relay healthiness. f) Trip circuit fail 1 N/O contact. This contact will indicate the trip circuit failure condition. g) Timer output - 1 N/O contact. This contact to be used for time delay functions Primary Injection Primary injection tests are essential to check the ratio and polarity of the transformers as well as the secondary wiring. Ensure the instrument transformer is potential free and isolated from the primary system. Using the circuit shown in Fig.2, check the voltage transformer ratio and VT phase to earth connection. Inject a voltage of sufficient magnitude.the secondary voltage is 20

22 Vs = Primary voltage / VT ratio 5.4. Putting Into Service After completing all tests satisfactorily, the relay should be put into service as follows: 1. Make a final check of the secondary wiring and tightness of all terminal connections. 2. Insert the DC supply fuse. 3. Check the relay healthy indication/display. 4. Replace the relay cover. 5. Insert the trip links. 6. Perform trip test by secondary injection. 7. Remove all test connections Variable single Phase AC supply Double Pole Switch* V O/V START TIME INTERVAL METER 23 + ve D.C SUPPLY - ve STOP 3 4 * Use Good Quality Switch Fig.1 Secondary Injection Timing Test 21

23 MVT 181 U/V or O/V V D.C SUPPLY + ve - ve PRIMARY INJECTION TEST SOURCE Fig.2 Primary Injection Test Circuit Double Pole Switch* DC POWER SUPPLY SOURCE +ve -ve STATUS ** INPUT START TIME INTERVAL METER 23 D.C SUPPLY STOP 3 4 * Use Good Quality Switch ** Nominal Voltage for Status Input is 24/30V DC. For higher voltage use external dropper resister as detailed in the MVT181-Wiring Diagram. TIMER OUTPUT Fig.3 Close prevention Timing Test 22

24 T R I P S U P P L Y + VE TRIP CO NTACT 52 a TRIP COIL - VE 52 b VOLTAG E INPUT R1 STATUS R2 INPUT 1 R3 STATUS R4 INPUT 2 See Note 1 AUXILIARY + VE SUPPLY - VE EARTH MVT ALARM 2 3 TRIP 4 13 CO MMON 14 ELEMENT 1 O PERATED 15 ELEMENT 2 OPERATED 18 PROTECTION UNHEALTHY 21 TRIP CIRCUIT FAIL 16 TIMER 17 O UTPUT 19 STARTER 20 Fig.4 MVT WIRING DIAGRAM (-)Ve (+) Ve Earth CASE TERMINALS VIEWED FROM REAR Note : 1. Status input is rated for 24 / 30 V DC nominal voltage input (18 to 36V operating range) without any external resistors. For higher DC nominal voltage input, use external dropper resistors (R1, R2, R3 & R4) as follows. Nominal Voltage 48V DC 110V DC 220V DC Status Input External Resistances R1, R2, R3 & R4 Operating range 36 to 60V 88 to 135 V 176 to 280 V 1.0 kw ± 5% ; 9 W 3.9 kw ± 5% ; 9 W 8.2 kw ± 5% ; 9 W 2. Terminal No.23 (Earth) is to be connected directly to Earth bar. 23

25 NOTES 24

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