ECN Electrical Forum - Discussion Forums for Electricians, Inspectors and Related Professionals

Topic Options
Rate This Topic
#166310 - 07/17/07 03:51 PM Humming in Cubicle of Medium Voltage Switchgear
windmiller Offline
Junior Member
Registered: 12/05/06
Posts: 43
Loc: Alaska
Hi,
I have noticed a humming that recently started in a section of medium voltage switchgear. it operates at 13.8 kV.

Could this be a harmonic imbalance or loose bus bar?

Thanks for any replies.

regards

Windmiller
_________________________
We all live under one King
Top
Work Gear for Electricians and the Trades
#166327 - 07/18/07 03:59 AM Re: Humming in Cubicle of Medium Voltage Switchgear [Re: windmiller]
Zog Offline
Member
Registered: 09/13/05
Posts: 120
Loc: Charlotte, NC
Yes, could be either of those or you could have tracking. If you can arrange a shutdown do it as soon as possible. A visual inspection of all insulating surfaces should be done looking for signs of tracking, use a black light for the inspection that will make it easier to find any traces of nitric acid.
If you cant shut down a visual inspection with a corona camera would be best.
_________________________
MV/HV Testing Specialist, "BKRMAN"
Top
#217356 - 06/24/16 04:46 AM Re: Humming in Cubicle of Medium Voltage Switchgear [Re: windmiller]
highvoltpower Offline
New Member
Registered: 06/23/16
Posts: 1
Loc: India
Surely, listen for popping, or cracking sounds produced by electrical discharges also humming sounds or vibration produced by quality. With lights out, look for blue or purple corona halos. Orange or red sputter arcs are created by intermittent sparking. Best way is you cannot blackout a graphic checkup with a halo.
Top
#217357 - 06/24/16 07:37 AM Re: Humming in Cubicle of Medium Voltage Switchgear [Re: windmiller]
twh Offline
Member
Registered: 03/11/04
Posts: 901
Loc: Regina, Sask.
Thermal imaging is a nice way to find problems like loose connections. The heat stays for a while after it's turned off so you have some time to look around.
Top

Member Spotlight
Member Since: 02/23/13
Posts: 204
New in the Gallery:
SE cable question
Featured:

2017 NEC and Related
2017 NEC
Now Available!

Shout Box


Who's Online
0 registered (), 59 Guests and 9 Spiders online.
Key: Admin, Global Mod, Mod
 
New in the Gallery:
SE cable question
 
Top Posters (30 Days)
Admin 51
HotLine1 43
gfretwell 17
Trumpy 16
Ruben Rocha 13
 
Newest Members
clee512, Jdscott2005, FAIZAN, Regitest2, sureshazhagai

ECN Electrical Forums - sponsored by Electrical Contractor Network - Electrical and Code Related Discussion for Electrical Contractors, Electricians, Inspectors, Instructors, Engineers and other related Professionals