Lightning Arrestors
Lightning Arrestors
(OP)
Could anyone give me some insight into the causes of a lightning arrestor failure on our plants high voltage (34kV) service. The rep from the local power company told me the line was reset 3 times, twice on auto-reclose and once manually. The arrestor appeared to have been blown to bits and ignited a fire in the brush. I believe the arrestor was of the air gap type. Needless to say, I would like to prevent this from happening in the future. Any suggestions towards this end are greatly appreciated.






RE: Lightning Arrestors
If you are on the North American continent, IEEE Transactions on Power Delivery returns a dozen hits for “arrester failure” doing a search at ieeexplore.ieee.org If you are not an IEEE member, the papers {more recent in PDF} can be purchased outright.
RE: Lightning Arrestors
RE: Lightning Arrestors
What was the weather like in the area at that time?
Has this happened before?
What is the physical conditons at the site and at the LA? Dusty? Muggy? damp, wet? clean?..
Any possibiliy of resonance?
RE: Lightning Arrestors
It is known that earth fault in one phase causes voltage in other phases to ground to raise up to a level of 1.732 times normal Ph-E voltage.
This higher voltage means increased stress on the LA and can lead to its failure, especially when it o happens in quick succession as in the subject incident. If the LA failed belongs to the healthy phase, the above explanation should be valid. You may like to verify.
The above tries to supplement the other good suggestions by others such as ageing of LA, actual lightning strike.
RE: Lightning Arrestors
1- Improve the resistance of the SA lead cable:
a- Measure the actual resistance.
b- Add additional ground rod(s).
c- Replace/add ground conductor to reduce resistance.
2- Replace the damage air-gap surge arresters by metal oxide units. Made sure to elect Intermediate or station type with adequate energy release capability.
RE: Lightning Arrestors
RE: Lightning Arrestors
RE: Lightning Arrestors
stevenal — Do you know if 'non-brisant' failure of polymer-housed devices is thought to originate from moisture ingress?
RE: Lightning Arrestors
On ungrounded systems, that number could rise to 6x or 7x due to capacitive charging.
RE: Lightning Arrestors
I'm sure moisture accounts for lots or most of failures regardless of the housing material. We see arrester failure as a problem, but porcelain shrapnel is a safety issue that can be avoided.
RE: Lightning Arrestors
Agreed that ringing in one’s ears is desirable to airborne ceramic shards plus the ringing.