Transformers : Lightening Arresters

Lighting arresters are also know as surge arresters. A switching or lightning surge can create enough movement in a winding to cause damage to the coil and core assembly. Using IR for LA’s is only one test which must be done. The leakage current on a good arrester is so low that the arrester should not have any temperature rise above ambient. Any temperature rise that is detectable with an IR camera indicates that the leakage current is on the rise and it will continue to increase until thermal runaway and failure. Using the high frequency current transducer clamped to the LA ground lead will give clues that the IR will not see.