Message Board Thread - "Electrical Distribution Arrestors"

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Electrical Distribution Arrestors Steve Beyer 2/25/2004
Looking for anyone with experience scanning electrical distribution type lightning arrestors. Is it possible to determine expected failures at specified high temperature extremes?
Any help is greatly appreciated.
Re:Electrical Distribution Arrestors jdemonte 3/2/2004
This is a big issue with many of the utilities across North America right now, Steve. Some say that ANY temperature rise on a lightning arrestor (LA) shows that it is need of immediate attention. Others are looking at a severity criteria that shows when they are moderate, intermediate, or severe in their failure condition. It is my opinion that LA's should not show any heat that is current related. Make a note of environmental influences such as the sun or other issues prior to calling one bad, but I typically recommend that they get replaced when they are showing any higher temps than your reference LA's.

You can take it one step further, and discover the root cause for any LA's that have broken down on you. Build a case history and use it to eliminate the cause of the failures.... whatever they may be.

Re:Electrical Distribution Arrestors Doctir bob 3/2/2004
Richard Strmiska of Sumter Electric Cooperative gave a great paper on lightning arresters at the 2003 InfraMation Conference.
Re:Electrical Distribution Arrestors DPR 3/3/2004
IR can be an excellent tool for evaluating lightning arresters. However, there are some important points to keep in mind. You should have a good understanding of the internal design of the arrester you are examining. In general, surface temperature measurements are considered indirect measurements related to the internal design of the arrester. Determine what type of arrester you are observing, e.g. is the arrester an older silicon carbide gapped type or newer metal-oxide gapless type. Also, polymer and porcelain housings will transfer heat differently.

Arresters that are showing signs of heating should be investigated further. Each arrester design has particular thermal characteristics. For a suspect arrester, the time to thermal runaway may vary depending in part on the nature of the degradation, system events and environmental conditions. A suspect arrester that is operating at an elevated temperature now has a reduced capacity to absorb energy during a system event and therefore should be replaced.
Re:Electrical Distribution Arrestors Steve Beyer 3/4/2004
Thanks to all for your input. I greatly appreciate it. We recently had Gentleman from Hubble and Joslyn give us presentations on distribution arrestors which was also very helpful. They both mentioned water intrusion has been a major factor in failure of older Ceramic style units. I have requested IR studies/info from Joslyn.

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