SITE TESTING OF LINE DIFFERENTIAL RELAY

1.Analog input Measurements 

Inject the rated secondary CT & VT values and check the primary and secondary values and power values  in the relay.

2.Input and Out put card checks

Give the digital input commands check the response in the relay
Check the all output contacts of the relay

3.  LED status

Check the all LED status as per configuration

4. Secondary injection tests 

4.1 . Check all settings are applied for function
4.2.  Zone reach measurements
4.3. Zone timings
4.4. Phase selection function
4.5. Power swing
4.7. Switch On to faults
4.8. Scheme communication Logic
a. Permissive under reach
b. Permissive over reach
c. Blocking scheme
d. Direct inter trip scheme
e. DIST WEI ECHO
g. Current reversal Logic

5. Over current & Earth fault function 

6.DEF COMMUNICATION SCHEME

6.1. Permissive over reach scheme
6.2. Blocking scheme
6.3. DEF WEI ECHO
6.4. DIST WEI TRIP
6.5. Current reversal logic

7. Fault locator function

8. Differential Function

8.1. Communication failure checks
8.2. Pickup/ Drop off Id min
8.3. Time measurement for Id min &  Id min High
8.4. Alarm checks
8.5. Bias Characteristic Testing
8.6. Harmonics Restraint Checks

9. Auto Re-close Checks