Wondering what the test voltage is for a 15kv vacuum breaker (13.8kv nominal voltage) for AC hipot. Maintenance test. Thanks!
Wondering what the test voltage is for a 15kv vacuum breaker (13.8kv nominal voltage) for AC hipot. Maintenance test. Thanks!
First, manufacturer's do not differentiate between acceptance and maintenance test values for vacuum integrity test.
Second, each manufacturer has a specific test voltage for each voltage rated vacuum breaker. So, to answer your question would require the manufacturer and type of breaker. My recommendation would be to look up the manual for that breaker and under vacuum integrity/withstand testing look for the appropriate voltage level.
NETA has testing voltage at 27 kV for the 2019 version, but any manufacturer literature will always supersede this.
General Electric breakers sometimes will ask for Vacuum Integrity testing at 36 kV for 10 seconds.
If you think about it, the contact gap is less than 1/2" on any vacuum bottle. If you apply over 10kvac across 1/2" gap that is solidly grounded on the other pole I am pretty sure it will fail.
This is a go, no go test.
There is no state in the real world that is a partial vacuum.
If the bottle vacuum is compromised it will fail.
I have tested thousands of vacuum bottles on VB1 type breakers with the ML-17 and ML-18 mechanisms at 36 kV in accordance with the manufacturer service literature. Vacuum interrupters that still have integrity to the "vacuum" will withstand this voltage for 10 seconds without failure. The contact travel for these breakers is roughly 0.55" (0.54" - 0.6" nominally).
I have tested a few 27 kV breakers (VCP-Ws I believe) that called for over 40kV testing voltage and the vacuum interrupters were able to withstand test voltage without failure.