7PG21 Solkor Rf Commissioning
©2012 Siemens Protection Devices Limited
Chapter 6 Page 16 of 21
3.3.7 Test of guard relays (where fitted)
If it has not been possible to check the operation of the guard relays by primary injection then the following tests
should be done.
Connect a temporary short circuit across the CT’s at both ends of the feeder. Disconnect the red phase guard
relay from the CT secondary at one end of the feeder.
Using the test circuit shown in Fig. 7, check the pick-upvalue of the relay at the chosen setting.
Slowly reduce the current until the relay resets. The rest value should be greater than 75% of the pick-up value.
Repeat these tests for all the guard relays at both ends of the feeder.
At the conclusion of the tests, re-connect the guard relays on the C.T. secondaries and remove the short circuit
from the C.T’s at both ends of the feeder
.
3.3.8 Test of pilot supervision supply failure relay (where fitted)
Disconnect the supervision supply failure relay from the transformer-rectifier supervision supply unit.
Using a variable a.c. voltage supply, check the pick-up value of the relay.
Slowly reduce the voltage until the relay resets.
The pick-up value of the relay should be approximately 80% of nominal rating.
3.3.9 Overall tests of pilot supervision equipment
Check that the pilot supervision equipment is connected correctly to the pilots and that all other connections are
normal.
Connect a d.c. milli-ammeter in series with the pilot supervision relay.
Check that the a.c. supply to the transformer rectifier supply unit is connected to the correct transformer tapping.
Fig 6 Secondary Injection test of
Fig 7 Secondary Injection test of guard
Pilot Supervision Receive Relay
Relays. (Refer to relevant schematic for
Terminal
numbers)
