Deterioration of xlpe insulation in high voltage cable systems and testing of quality by applying pulses of high voltage

Abstract

The wide spreading of energy distribution power cable lines made by means of applying cables with insulation made of cross-linked polyethylene usually is associated with a significant number of advantages in terms of better technical performance that such cables have in comparison with traditional cables with paper-impregnated insulation. Nevertheless, the necessity to ensure a sufficient level of production quality, as well as the requirements for increasing the operating time of power cable lines, make it urgent to develop insulation quality control methods, including control methods which imply applying of testing impulses that simulate overvoltages that occur in power systems due to lightning strikes. The other aspect of this problem is the necessity of the elaboration of physical models for the description of deterioration of XLPE insulation of power cables under the impact of various external factors. For recent years the problem of testing XLPE insulation by high voltage pulses, similarly to the problem of elaboration of physical models for the description of deterioration of XLPE insulation, have been considered by many authors. This paper gives a brief review of some main recent research that have been focused on the problem of endurance and aging of XLPE insulation due to overvoltage caused by various reasons. The main scope was focused on the problem of testing the endurance of XLPE insulation to the voltage pulses that imitate overvoltage due to lightning strikes. Some of the theories of aging of dielectric materials under the impact of impulse and alternating electrical fields and the influence of these factors on lifetime of dielectric materials have also been discussed.