There’s an awful lot of very cool stuff at PSNH’s huge substation in south Amherst, which handles much of the electrical load for Nashua, but maybe the coolest thing can’t even be seen: Coronas.
These electrical discharges occur when there’s so much electricity around that it ionizes air molecules, creating dancing colored lights. Think of St. Elmo’s fire appearing around sailing-ship masts during lightning storms.
Coronas don’t appear in the PSNH substation despite the staggering amounts of current flowing through it because of “corona rings.” Metal doughnuts hanging from the top of many components; these spread the electric field gradient so it isn’t potent enough to ionize the air.
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