7sa522 Finaltest Steps%%%

COMMISSIONING PROCEDURE FOR DISTANCE PROTECTION RELAY

This test procedure will describe the methods of testing of Distance Protection relay at construction/project sites. Instruments and test supply requirements: -•Laptop for communication with omicron and relay. •Test Plugs and leads. •1ph, 230V supply with proper earth for Omicron Test Equipment. OR •3ph, 415V supply with 7VP48/49/TURH Test Equipment. •Digital multimeters. •Test leads. Notes: A.

Programme the relay at approved settings if they are available, else testing can be done at factory settings.

B.

Please ensure that current during any test not to exceed more that 4 Amp for relay with 1 Amp rating. If the current exceeds 4 Amp then the thermal heating of the relay is to be considered and sufficient time gap to be maintained for cooling. Pl. refer technical data in section 10 of relay manuals for more details.

C.

Readings obtained during testing should be recorded in attached Commissioning Test Report.

D.

For permissible variations in current please refer the technical details mention in relay manual in section 10.

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Detail Procedure: 1. Physical Inspection: Carry out physical inspection for transport damage, auxiliary dc/ac voltage, proper earthing and nameplate details. Also check wiring tightness and CT shorting links. 2.

Put test/service switches in test position. Insret the test plug and connect the test leads for 3 phase current (Ter 1,2,3&4), voltage (Ter 5,6,7&8) and trip leads (Ter 9&10).

3. Measured value check: Inject rated three currents and voltages and check the displayed measured values and record them in test report. This test ensures that all your current and voltage connections are proper. 4. Direction Test: Check the zone direction test by blocking tripping of all zones and apply 2 Amp current with fault in zone and change angle of voltage with angle of current fixed. Record the readings of angles when the relay changes the direction. The change in direction can be checked from spontaneous annunciation of digsi, Function No. 3719-Distance pick up forward and Function No. 3720- Distance pick up reverse. Else program the functions on two spare LED’s and test the feature. 5. 3Io threshold: To test 3Io threshold check setting of address 1203. Block all trips, apply zero voltage and increase current in one faulty phase. Note the current at which the relay trips on distance fault. 6. Iph> current threshold: To test phase Iph> current threshold check setting of address 1202. Block all trips, apply zero voltage and increase simultaneously current in all three phases. Note the current at which the relay trips on distance fault. 7. 3Vo threshold: To test 3Vo threshold check setting of address 1204. Block all trips, apply 63.5 volt for all three phases and 2 Amp current in all three phases (three phase symmetrical fault). Slowly reduce voltage of one phase only. Note the voltage at which the relay trips on distance earth fault. Reading the spontaneous annunciations of the relay with laptop, we can check the earth fault tripping, Function No. 3675- Distance pick up earth. Note: distance relay may trip on phase fault while reducing voltage, ignore the same and reduce voltage further till the E/F pick-up. 8. Reach test EFS REF./DATE/CHECKED BY

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This test can be done easily with Omicron test kit as follows. Export the zones in rio format from the settings menu of digsi. The setting can be saved in floppy drive and then transferred to the omicron laptop. Them import it in omicron test kit from the distance menu, so that we can see the graphical view of all zones. Faults can be injected near the boundaries of zones and the reach can be noted when there is change in trip time, 0 deg faults will give resistive reach and 90 deg faults will give reactive reach results. Inject shots in each zone for all types of faults and note the trip time. If the reach test is to be done with 7VP48/49 test kit. Select the type of fault, keep voltage knob at maximum and adjust current to 2 Ampere. Adjust the phase shift to zero. Then slowly reduce the voltage and note the voltage at which the relay trips on the last zone i.e. zone 4. Similarly note reading with 90 deg phase shift. The pick up voltage can be calculated from the formula and table given below. For the reactance interactions. U pick up= I injected*X reach* K For the resistive interactions. U pick up= I injected*R reach* K K factor depends on the type of fault and angle and is given in table below. Type of K K Fault ø= General ø= General 90/2 0/180° 70° 1 Phase 1 1/(Sin ø) 1 1/(Cos ø) 2 Phase 2 2/(Sin ø) 2 2/(Cos ø) 3 phase 1+Xe 1+Xe/Xl/(Sin ø) 1+Re/R 1+Re/Rl/(Cos ø) /Xl l Now disable the zone 4 by keeping it trip time to infinity. Again note the reading of pick up voltage at which the relay trips in zone 2. (Zone 3 is normally set for reverse zone). Similarly we can check reaches of other zones.

9. Back up overcurrent : This feature can be checked by switching OFF distance protection. The pick up of definite time overcurrent is EFS REF./DATE/CHECKED BY

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approximately same to the set values. For the inverse curves the pick will be 10% more that the set value of overcurrent. The trip time can be checked as per the selected curve. All the relevant address of settings are mentioned in the test report. All relevant address settings are mentioned in test report. 10. Earth fault feature with teleprotection : This feature can be checked by simulating the carrier receive signal to the programmed binary input. When carrier signal is received the tripping is instantaneous. If no carrier signal is received the tripping is as per set time T3Iop. 11. SOTF: Switch On To Fault can be checked by injecting current above the set value 2.5 Amp (address 2404) and simultaneously giving manual close input. The relay will show S-O-T-F trip on the display. This feature can also work even when voltage is absent. Note down the pick up current and trip time at 1.5 times the set current. 11- FOR Z1B SIMULATE FAULT AT Z1B AND GIVE A MANUAL CLOSE = TRIP AT 0 TIME. 12. Teleprotection for Distance Protection •

Permissible Underreach Transfer trip with Zone extension Simulate fault at 90% of line length just after zone1 and same time simulate carrier receive signal. Note if carrier signal is received then the relay trips in ZIB time for faults in Z1B, else the relay trips as per individual zone time. Check carrier signal send for each fault in zone 1.

•

Permissible Overreach Transfer trip with echo. Check carrier send signal for ZIB faults. Trip time without carrier receive binary input signal is equal to Zone 2. Trip time with carrier receive binary input signal is equal to zone1B time. If carrier signal is received and no fault is detected, status of echo signal is as below. With CB ON: echo signal after 40 msec. (Set 40 ms, address 2502a) With CB OFF: echo signal at 0 msec (Immediate)

•

Permissible Overreach Transfer trip with Signal comparison Simulate fault at 90% of line length. Note if carrier signal is received then the relay trips in ZIB time for faults in Z1B, else the relay trips as per individual

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zone time. Check carrier signal send for each fault in zone1B. •

Direct Transfer Trip (DTT) Note trip for z1b faults after receipt of direct transfer trip via binary input in ZIB time.

•

Blocking mode Simulate fault in reverse direction and check carrier send signal. If blocking signal is not received ZIB is instantaneously tripping.

•

Unblocking mode Simulate fault in Z1B. Monitoring frequency is achieved. Check programmed contact. Carrier signal send for each fault in zone.

•

1-Week Infeed: Apply only 3-phase voltage. Simulate carrier input signal. Slowly reduce voltage of one phase, the relay will trip on week infeed. Note the 3Vo voltage in the table. 2- reduse the time 30 sac= min 3- cb switch on 4- simulate receiving signal 5- cb will trip

13. Fuse failure: This is checked by injecting nominal voltage and current in all three phases and Remove one voltage, distance is blocked and fuse fail indication appears after 10 sec. Blocking of distance protection and switchover to back up overcurrent can be also checked in the spontaneous annunciation menu. Remove all three voltages, distance is blocked and relay switches over to emergency overcurrent mode. Reduce slowly one voltage and measure fuse failure threshold voltage. Fuse fail is detected for 3VO above 30V (Setting 30V address (2911A)) 14. Power swing: This can be checked by injecting nominal voltage and current in all three phases. Slowly reduce the voltage in small steps until the power swing detected alarm comes and the LED is displayed, if the voltage is further reduced then we can check the blocking of zones as per setting of address If zone1 tripping is not blocked then the relay trips in zone1 during power swing.

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15. Fault records stored in the relay can be checked by downloading for correctness of current and voltage values 16.

Fault locator correctness can be checked by injecting reactive faults at the zone boundaries and the kilometre shown on the display after trip can be verified. This kilometre is directly proportional with the address 1110 set for secondary reactance ohm/km. 17- AUTORECLOSURE 1- CB READY TO BE CONFIGART 2-CB OFF&ON TO BE CONFIGART

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