LT Protection Relay Test
Testing Diagram and Testing Procedure.

  1. LT protection relay test
  2. Testing Diagram.
  3. Testing kit specification.
  4. Safety guideline of testing.
  5. Testing Procedure.
  6. Parameters observation.

1- LT protection relay test:

Now a days the digital protection relay mostly are using. If we want to check health performance then we will have to test of relay. First relay performance test is carried out after commissioning after that relay testing is carried out as base of annually time schedule.

Pre set value or protection relays are verified or tested through test equipment. a all protection relays are also carried out maintenance activity. All connections are checked and clean properly.

2- Testing diagram of protection relay test:

LT panel protection relay: testing diagram and procedure.

3- Test kit specification:

Relay testing kit has many specification according time and characteristics which below mentioned.

  • Input voltage: 230 V AC, 50hz
  • Output AC voltage : 0- 230V AC
  • Output AC current: 2 Amp
  • Output DC voltage : 0- 230V DC
  • Output DC current: 2 Amp
  • Current source selection: 0-5-25-50 Amp.
  • Time interval meter for time measurement.

4- Safety guideline for protection relay test:

  • Use LOTO- lock out tag out before testing.
  • Rack out the circuit breaker.
  • Connect the earth wire with relay test equipment.

5-Protection relay test procedure:

1- Relay setting types for testing:
  • Over load
  • Short circut
  • Instantaneous earth fault.
  • Earth fault.
2- Testing procedure:
  • All safety guideline should be followed during testing procedure which is mentioned above.
  • Open the panel relay cover with carefully.
  • Connect the single phase supply in relay test instrument.
  • Connect the earth wire with relay instrument body.
  • Connect the instrument test lead into relay feed points.
  • Set the fault current and time in relay instrument according pre setting.
  • Press the test button and after receiving fault current the relay will be tripped and verify to the pre set value.
  • Re set the relay .
  • Same type procedure will be followed for relay other setting which below mentioned.

6-Protection relay test observation. :

Test all relay according pre set value of setting. Verify the pre set value of protection relay. If relay is not activating on fault current then find out the problem or replace the relay. All protection relay are also carried out the maintenance.

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