Selector isolator for HV testing of encapsulated switchgear - involves bulkhead insulation plate eliminating need for degassing large sections of ducting

摘要

The purpose of the selector isolator is to facilitate the HV testing of new installations thereby saving time and wear on equipment. Connections are brought out of the bus ducting (12) through a bulkhead insulation plate (13). A separate housing (1) containing the HV test bushing (2) and selector switch mechanism (3) is bolted onto the end flange of the bus duct. Thus only the end (14) of the duct and the switch chamber (15) have to be evacuated and filled with insulating gas for the test. Typically the selector is controlled by a hand wheel (11) driving through an insulation shaft (10). The contacts (7, 9) are all well rounded to minimise discharge at the high test voltages. Contact with the busbar ends may be by means of a spring loaded pin (9).