Distribution Systems Insulation Coordination
The practice of distribution system insulation coordination is very limited; however, there are some very specific deterministic practices that are quite important. The margin of protection calculations for some system configurations can determine when to and when not to use arresters. For instance, on underground circuits where voltage doubling is common, a margin of protection calculation can reveal that applying an arrester only at the riser pole for systems above 25kV can be a problem. When this is the case, an open point arrester is