×
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

33kV Insulator dust deposits

33kV Insulator dust deposits

33kV Insulator dust deposits

(OP)
Hi all,

We found dust spots (dust concentration) in the surface of an insulator (the trafo is under roof), and carbon spots also. I've attached a picture of the insulator there you can see the spots.

Is it possible that this can be internal cracking? (the trafo is 1st year in service) The tech havent found anything looking at it.

I've noticed the same phenomena in cast-resin trafos HV windings (33kV)

Any help will be much appreciated!!

Note: i'm not an experienced medium voltage tech...

regards,
Martín

RE: 33kV Insulator dust deposits

Hard to tell from the picture, could have a corona issue there. Can you do a orona scan?

RE: 33kV Insulator dust deposits

(OP)
I´m sorry, I misspelled, it's a bushing. I'm not so good in english...

Some guy from the mill said saw it sparking, then a tech cleaned it, and then no more sparks.

But anyone can tell something similar? It seems insulator damage to me but I'm not that experienced in HV.

thanks!!

RE: 33kV Insulator dust deposits

Those "sparks" he saw probally looked like a purple force field around the bushing, it will come back, you need to replace that bushing when possible.  

RE: 33kV Insulator dust deposits

(OP)
What about dust spots/concentration?
I saw the same phenomena in the HV windings of cast-resin transformers

many thanks!

RE: 33kV Insulator dust deposits

From pictures difficult to predict but does not look like crack or something like that.  These look like carbon deposits. You need to check for reasons. Inded there was sparking as said in the post.

Follow basic electrcial maintenance principles - keep it clean, cool, Dry and tight.  And observe.

At first opportunity, lift and check for internal crack or sparking.  

Regards,

NC

RE: 33kV Insulator dust deposits

Maximum electrical stress in bushing is at mounting area ie to earth.If you are no-longer seeing any sparking nothing to worry.If the area is prone to too much dust pollution,better to apply silicon grease ( eg RTV) on porcelains so that performace is not affected by pollution.

RE: 33kV Insulator dust deposits

Colonite or Beaver butter are 2 products designed for this purpose.  

RE: 33kV Insulator dust deposits

(OP)
Great! Thanks a lot

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