XIPD testing of a 275 kV cable joint insulator

Diagnostic tests were performed on a 275 kV prefabricated cable joint insulator using a new test technology, the X-ray induced partial discharge (XIPD) test system developed at Ontario Hydro Technologies. Special shields were designed to facilitate the evaluation of PD characteristics of the large epoxy casting. The test chamber was PD free to 600 kV; discharges from controlled voids inserted near the conductor were readily detected. A PD sensitivity of 0.08 pC was achieved during testing at up to 600 kV. The cable joint insulator remained PD free under X-ray irradiation to the target test voltage of 420 kV.