Circuit breaker testing and questions

[bujaam]

Let me know if I have this right for the different tests performed on breakers. Is there an online resource for info on these tests?

Power factor - testing the Insulation of the bushing by applying a high voltage to the top and a lower voltage to the bottom of the same bushing of the same pole with the breaker open. I’m not sure what exactly we’re looking for here

Ductor - applying a high current across the contacts of a closed breaker and looking for a low resistance value. This seems pretty straight forward unless I’m missing something

Hi pt - applying a high voltage to the bushings of a breaker with one lead from the hi pt applying several kv to the breaker and another lead connected to ground(?). Used to check for leakage to ground through the insulating medium, I’m not sure how this works either.

Megger - same application as the hi-pt test?

Any help would be appreciated, I’m new and trying to learn about the different tests that are done

[Manon_Chaboud · Accepted solution]

Hello @bujaam. Thank you for your post! 🙂 

This is the information I can add for the different tests:

1. Power Factor Test:

   • The objective is to measure the power factor, which indicates the condition of the insulation. A lower power factor may suggest potential issues with the insulation.

2. Ductor Test:

   • A low resistance value is generally expected, indicating good electrical continuity.

3. Hi-Pot Test (High Potential Test):

   • It's used to check for leakage to ground through the insulating medium. If there is excessive leakage, it could indicate potential insulation issues.

4. Megger Test:

   • The Megger test is used to measure the insulation resistance of the breaker. It involves applying a high voltage to the insulation and measuring the resistance.
   • It differs from the Hi-Pot test as it specifically focuses on insulation resistance.

As for online resources, I recommend referring to industry standards and resources for detailed information on these tests. Additionally, manufacturer documentation for specific breakers may provide detailed testing procedures.