Investigation on characteristics of 275 kV XLPE cable removed from actual service line

XLPE cables have been increasingly employed for the actual lines, replacing oil-filled cables. In the extra high voltage field, more than ten years have passed since the first installed 275 kV XLPE cable in Japan. Recently, technical requirements for a diagnostic method for actual service lines have been increasing. A lot of available information on the method was expected to be gathered by the investigation about actually used 275 kV XLPE cables. The Tokyo Electric Power Co. Inc. and Fujikura Ltd conducted various electrical tests and physical tests on the first 275 kV XLPE cable by removing it from the actual service line to check its insulation performance and the state of deterioration in physical properties of the cable materials. The cable investigated was manufactured by dry curing method and constructed with a corrugated aluminium sheath, which means no water will penetrate into the cable. No serious deterioration was observed for the removed 275 kV XLPE cable