The poles of PVB are capsulated by insulated material which is Hydrophobic Cycloaliphatic Epoxy (HCEP) and the poles are installed vertically on the mechanism tank (see rightside picture). Poles casted by HCEP canminimize partial discharge and mechanicaldamage. When PVB is closed, current path of the main circuit is:upper teminal→static contact in the vacuum interrupter→dynamic contact in the vacuum interrupter→lowerterminal→external circuit.
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