PARTIAL DISCHARGE MEASURING METHOD

PURPOSE:To measure partial discharge on an AC basis by a small-capacity power source by projecting X rays and lowering a partial discharge start voltage temporarily. CONSTITUTION:A connection box to be tested is irradiated with the X rays 32 to lower the partial discharge start voltage of the part temporarily. Consequently, a connection part 12 is irradiated with the X rays 32. Therefore, the voltage of the AC power source 16 required to test a void can be made low and the capacity of the AC power source 16 is reducible. Measurements are taken as to respective connection parts 12 to specify which connection part 12 is defective.