Electroluminescence for XLPE cable diagnosis

Electrical treeing is responsible for the breakdown of power cables with polymeric insulation, such as low density polyethylene (LDPE) and cross-linked polyethylene (XLPE). Electroluminescence (EL) occurs in the initiation phase of electrical tree. We studied the characteristics of EL in XLPE cut from 77 kV class power cables. We found that EL intensity in XLPE cut from removed cable gradually decreases with voltage application time compared with that in unaged XLPE. This tendency is considered to reflect the degradation in XLPE.