The effect of thermal ageing on low voltage cross-linked polyethylene insulated cable

Abstract

This research presents some results and discusses the investigation on thermal ageing of low voltage cross-linked polyethylene (XLPE) insulated cable rated at 0.6/1(1.2) kV. This type of cable was found to experience premature degradation within three to five years of service. The objective of this investigation is to study the characteristic of XLPE insulated cable under thermal conditions. A number of tests were conducted to investigate the chemical properties, electrical properties and mechanical properties of unaged and aged XLPE insulated cable. Samples were thermally aged using air ventilated oven at temperature of 90 oC. The breakdown strength of XLPE materials were measured for each samples. The structural changes due to the formation of carbonyl groups were observed using Fourier Transform Infrared (FTIR) spectroscopy. The application of Differential Scanning Calorimetry (DSC) revealed the effect of thermal ageing on the crystallinity variation on XLPE insulated cable. Mechanical properties were observed through tensile strength test. Experimental findings in this study suggests that thermal ageing induces significant degradation on XLPE insulated cable.