Researches in a fast measurement of space charges for judging the degradation of power cables

点击翻译按钮获取中文摘要

A residual voltage of an insulator has been observed in an open circuit after a DC voltage was applied to the insulator. Recently, it is known that a residual voltage of the DC power cable depends on the degradation of it. So, measuring the residual voltage of the cable is considered to be one of useful methods to judge the degradation.We have made researches in a fast measurement of space charges for judging the degradation of power cables. In the researches, the characteristics of the residual voltage due to trapped charge carriers are studied. A new technique to determine the amount and the mean position of the trapped charge carriers is developed. And the measurement for a polyetylene (PE) film is carried out. Furthermore, new simple techniques of the residual voltage are developed to judge the polarity of trapped charge carriers in insulators and to measure the charge distribution. In the residual voltage measurements, the temperature difference is given between two electrodes of the insulator.Therefore, detrapping properties of the trapped charge carriers depend on the position, and the spatial information of carriers is obtained. The measurements are considered to be useful to judge the degradation of power cables.