Page 98 - Practical Power System and Protective Relays Commissioning

96 Practical Power System and Protective Relays Commissioning

FIGURE 7.12 Test connections for circuit breaker in open condition.

The applied test voltage limits shall be in the range of 1000 2500 V DC
for CB’s up to 5 kV (AC) and up to 5000 V DC for CB’s above 5 kV (AC).
Test connections are shown in Figs. 7.12 and 7.13 for an outdoor oil CB
with six bushings. Fig. 7.12 shows the test connections for a CB in open
condition and Fig. 7.13 shows the test connections for a CB in closed condi-
tion, where STOCB is a single tank oil CB; G is the guard, L is the phase,
and E is the earth.

7.6.3 High-Voltage Test

This test is done during the switchgear high-voltage test. The AC high-
potential test will stress the CB insulation similarly to the stresses which