Page 33 - Practical Power System and Protective Relays Commissioning

Introduction to Testing and Commissioning of Power System Chapter | 3 29

All of this should be carried out before the loading of the new circuit.
After loading of the circuit gradually by the NCC the following should
be done:
1. Check the values of each current on each phase for protection relays on
each protection panel, including the metering panels.
2. Perform directional tests for directional and distance relays with at least
10% 30% of load current depending on whether it is an electromechani-
cal or digital relay.

3.10 AC DISTRIBUTION PANEL COMMISSIONING TESTS
3.10.1 Visual Checks
A visual check should include the tightness of bolts of the low voltage
AC busbars with torque wrench tool. Also checking the MCB and CB
ratings as per drawings and checking of panel earthing (correct cable
cross-section).

3.10.2 Electrical Tests

An electrical test can include any of the following:
1. Insulation resistance tests.
2. Phasing check for cables.
3. Calibration of meters and ampere and voltage meters.
4. Checking of auxiliary relays.

3.11 DC DISTRIBUTION PANELS COMMISSIONING TESTS
3.11.1 Visual Check

This check should include the MCB ratings and CB ratings as per drawings,
the tightness of bolts of busbars with torque wrench tool and checking of
panel earthing (correct cable cross-section) for earthing.

3.11.2 Electrical Tests
An electrical test can include any of the following:

1. Insulation resistance of all busbars and internal wiring in the panel.
2. Polarity check.
3. Operation and trip of MCBs.
4. Checking of earth fault relay on this panel.