Assessment of Thermally Aged Cross Linked Polyethylene Insulation Under High Impulse Voltage Stress

In high voltage cables, various types of of solid, fluid and gaseous materials are utilized for insulation reason to protect high voltage (HV) power equipement. Service cables are exposed to different stresses i.e. natural aging, electrical stress, mechanical stress, thermal stress etc. which are main causes of reduction of dielectric strength of insulation that leads to cable failure. Due to its high dielectric strength, Cross Linked Polyethylene (XLPE) is used in most of the high voltage (HV) cables for insulation purpose. The reason behind most of the HV cable unable to carry bulk power due to internal discharge happen in inner most parts of the insulation. In order to get advance information about the health of HV cables periodic condition monitoring of XLPE insulation cable is needed. In this work, chemical and electrical properties of thermally aged cross-linked polyethylene (XLPE) insulation was examined, by means of Fourier transform infrared (FTIR) spectroscopy and impulse breakdown voltage measurement respectively.