Study on diagnostic method of aging 10kV XLPE cable

With the widespread use of XLPE cables, the faults caused by the cable indicate the increasing trend of multiple and frequency, its running state has a direct relationship with reliability of power system. By surveying 10kVXLPE cables' status of Guangzhou city, we find that aging is the main factor causing the insulation breakdown. And then a 10-meter cable out of service was accelerated aging under overload current and overvoltage in the lab. After that XLPE samples cut from the cable insulation before and after the accelerated aging experiment separately, were analyzed through OIT (oxygen induction time) test, crystallinity, content of O element. The results, compared between XLPE samples, suggest that overload and overvoltage can shorten the OIT and increase the crystallinity degree of XLPE and its content of O element, which are the characteristic parameters to assess the cable aging. Finally, a case of cable ageing diagnosis, combining with 0.1 Hz tan6 detecting, was given to illustrate how this diagnostic method of 10kV XLPE cable works efficiently in Guangzhou networks.