Page 370 - Practical Power System and Protective Relays Commissioning
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366 Practical Power System and Protective Relays Commissioning
3. Between F3 and F4 at point 3 and point 5 with C.B4 and Q 17 and Q 11
and Q 2 and Q 5 are closed and the above test is repeated with an injection
between point 5 and point 4 with C.B4 and Q 17 and Q 12 and Q 4 and Q 6
closed.
4. Between F6 and F5 at point 5 and point 6 with Q 17 and C.B4 and Q 11
and Q 13 and C.B5 and Q 18 are closed and the test is repeated with Q 17
and C.B4 and Q 12 and Q 14 and C.B5 and Q 18 closed.
5. For all the above tests the secondary currents in protection, metering, and
busbar protection panels for each phase (R, Y, B) are measured and the
results recorded in a proper test sheet. All current transformer (CT)
phases should be read to confirm the correct values in all panels in the
substation based on CT ratios.
22.2 ENERGIZATION OF SUBSTATION TEST
Before energization the following points should be checked:
All commissioning test are completed and have acceptable results;
All shorting links on CTs are removed and all miniature circuit breakers
(MCBs) are on;
All relays are set to the final setting;
All trip tests for all relays are done;
No earthing is left on any primary circuit;
Visual checks for power transformers for power cable termination, cable
box cover oil level, and cooler fan setting;
Visual check for SF 6 pressure in gas insulated system;
All work permit, switching program; and commissioning overcurrent tem-
porary settings are all ready at the site;
All safety signs are there before energization.
After energization the following points should be carried out:
Secondary voltage measurements to be checked in all points in all panels;
Phase sequence to be checked;
Phasing checked before paralleling two circuits;
After loading the circuit all secondary currents to be measured in all
panels and all phases;
Directional test to be done for directional relays such as directional over
current (O/C) or Earth fault (EF) relays and distance relays;
Stability test for differential relays during circuit loading by reversing the
polarity of the secondary currents and the performance of the differential
relay checked;
Load test of automatic voltage regulator for transformer.