When Outbuild Meets Underbuild: Surge arresters provide a simple solution to a complex overvoltage problem

摘要

It was one of those so-called "overvoltage events." Somehow overhead wires from the top and bottom circuits made contact. The cause was a tree contractor removing a diseased tree at a private residence. One particularly troublesome limb that had been cut had fallen into the line, bridging the top phase with one from the lower circuit. The result was predictable. The isolators on several surge arresters were blown on the lower distribution circuit and some transformers failed, too.