Electric Automation Forum
Forum » General Discussion » Gas insulated HV Switch Gear
Topics: Gas insulated HV Switch Gear on General Discussion
#1
Start by
Benard Kigozi Kasolo
09-17-2013 03:17 PM

Gas insulated HV Switch Gear

What causes the "hissing sound" in SF 6 Gas insulated HV Switch Gear?
09-17-2013 05:48 PM
Top #2
Robert Beltz
09-17-2013 05:48 PM
SHUT IT DOWN! This could be internal corona discharge. The switchgear should be de-energized and closely examined. That means pump out the SF6 and take it apart. Examine all insulating components.
09-17-2013 08:20 PM
Top #3
Allan Stevens
09-17-2013 08:20 PM
I agree with Robert's recommendation, especially if the sound can be localized to portions of the switchgear which do not have bushings for connection to overhead lines. Even if the sound is in the area of air bushings, deenergizing will allow more in-depth inspection and addressing any sharp edges or cracked insulators, etc.
09-17-2013 10:45 PM
Top #4
Randy Beltz
09-17-2013 10:45 PM
Robert and Allen are of course absolutely on point! Take this pieces of equipment out of service immediately, perform a "hi-pot" or high potential test on the various elements of the switchgear and attempt to locate the area that is "leaking" to ground (or between phases). Inspect closely for indications of tracking on insulators from corona discharge and replace any compromised components. After component replacement, installation of new SF6 gas and other repairs, re-run the Hi-Pot test to confirm that the switchgear is able to withstand voltages at least 50% greater than the name-plate rating. Of course all of this advice is worthless if the unit has already failed. Good Luck Benard!
09-18-2013 01:43 AM
Top #5
Benard Kigozi Kasolo
09-18-2013 01:43 AM
Thanks for your comments and advise, Let me plan for prescribed "ACTIONS". Keep that spirit.
09-18-2013 04:03 AM
Top #6
Marie Conrad
09-18-2013 04:03 AM
Remember that a Hi-pot is actually a destructive test. It challenges the insulation to the point of breakdown. Check the vendor recommendations before you Hi-pot equipment that has been in-service.
09-18-2013 06:41 AM
Top #7
Dharma Rao
09-18-2013 06:41 AM
I agree with Marie, but i don't think this will effect on SF6 SWG's . SF6 can fill easy and gauges will show us the reading values.

But Your point is more effective on XLPE/PVC Cables, Metal-Clad SWG's.
Reply to Thread