Page 368 - Practical Power System and Protective Relays Commissioning

A Guided Practical Value of Some Test Results Chapter | 21 363

6. Dielectric tests
HV test at power cycle 50 c/s
HV—E-230 kV
LV—E-70 kV
Tertiary—E-28 kV
For 1 minute
7. AC 31.2 kV at tertiary winding at 200 C/S test
For 30 seconds
Tertiary wilding-31.2 kV at 200 C/S
Then measure HV—E-460 kV at 200 C/S
Voltage per turn, 2.68 times the rated value.

21.2 HIGH-VOLTAGE TRANSMISSION LINE IMPEDANCE
VALUES
220 kV line
Bundle aluminum
R 1 5 0.14 Ω/km
X 1 5 0.4 Ω/km
X 0 5 2.04 Ω/km

21.3 GAS INSULATED SYSTEM TESTS
Disconnecting switch: contact resistance 5 10 μΩ
Earthing network resistance 5 10 μΩ
Gas insulated system (GIS) main circuit resistance 66 kV between 2 bays
with 100 Amp DC injected
R 5 160 280 μΩ
Circuit breaker operating time
T close 5 55 ms
T open 5 33 ms
Disconnecting switches
T open , 2 seconds
T close , 3 seconds
High-speed earthing switches
T open , 18 seconds
T close , 18 seconds
High-voltage test for GIS
Example:
For 132 kV GIS we apply 235 kV for 1 minute.
For 22 kV SWG we apply 50 kV for 1 minute.

21.4 LOW VOLTAGE PANELS
Torque wrench key 5 70 nm.