×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Insulation resistance test in vacuum
4

Insulation resistance test in vacuum

Insulation resistance test in vacuum

(OP)
Hello guys, i have a question on insulation resistance (IR) test.
When we conducted IR test with 5kV DC on a 132kV GIS busduct which is already degassing and in vacuum stage (means SF6 gas removed, and is under vacuuming close to 1 mbar), the insulation resistance value for the busduct L1 phase (or L2 phase, or L3 phase) to ground was very low (about 20Megaohm). But when the busduct filled with SF6, the IR value become 40Gigaohm.
I am a bit confusing, as i thought vacuum also a good insulation ? as we have vacuum circuit breaker which can withstand high voltage?

RE: Insulation resistance test in vacuum

2
Google the term "Paschen's Law".

RE: Insulation resistance test in vacuum

(OP)
Hi btrueblood, thank you very much!

RE: Insulation resistance test in vacuum

In power transformers it is a cardinal rule that never apply voltage under vacuum as it may result in insulation breakdown in windings.

RE: Insulation resistance test in vacuum

(OP)
Thank you prc and Zogzog

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources