Medium-Voltage Switchgear and Circuit Breakers:AC Hi-Pot Test

AC Hi-Pot Test

This test should be conducted separately for circuit breakers and switchgear buses (stationary gear). It should be made only after the DC insulation resistance measurement test has been passed satisfactorily and all cleanup has been finished. The AC test will stress the switchgear insulation similarly to the

Medium-Voltage Switchgear and Circuit Breakers-0254

stresses found during operating conditions. The maintenance test voltages should be 75% of final factory test voltage. These values are shown in Table 7.8. Hi-pot tests are made with the circuit breaker in both open and closed positions. The hi-pot test should be the last test conducted after all repairs have been made, cleanup is finished, and the insulation resistance test has been successfully passed. Procedures for the hi-pot test of the circuit breaker are as follows:

• The test connection for the hi-pot test is as shown in Figure 7.18.

Circuit breaker in open position:

Medium-Voltage Switchgear and Circuit Breakers-0255

Stationary gear (buses):

Connect HV lead to phase 1 as convenient

with phases 2 and 3 grounded. Apply the recommended voltage.

Repeat the test for phases 2 and 3 with other phases grounded.

Incoming search terms:

Related posts:

Leave a comment

Your email address will not be published. Required fields are marked *