CONTROL CIRCUIT FOR LIVE-WIRE OIL PURIFIER OF ON-LOAD TAP CHANGER

摘要

PURPOSE:To prevent the generation of an excessive temperature rising phenomenon in insulating oil by the preheating of an insulating oil heating-up heater by a method wherein, after a live-wire oil purifying process is completed and the heater to be used to heat up insulating oil is turned OFF, the operation of an oil-feeding pump is continued for a fixed period, and the circulating state of the insulating oil is maintained. CONSTITUTION:After a live-wire oil purifying process is performed for the prescribed period and when a time switch TS or a change-over switch CS is turned OFF, the state of excitation of a time-limit relay 30Y is removed, the auxiliary contact point (a) is turned OFF, the state of excitation of an electromagnetic contactor 88H is released, and a heater H is turned OFF. On the other hand, the time-limit return contact point (a) of a time-limit relay 30Y is turned OFF after the time-limit setting period is delayed. Accordingly, the operation of an oil feeding pump is continued during the time-limit setting period, and the circulating state of insulating oil is maintained, thereby enabling to prevent the generation of excessive temperature rising phenomenon in insulating oil caused by the preheating of the heater H.