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

对绝缘子施加直流电压后，在开路中观察到绝缘子的残余电压。最近，人们知道直流电源线的残余电压取决于它的退化。因此，测量电缆的残余电压被认为是判断电缆退化的有效方法之一。对空间电荷的快速测量方法进行了研究，用于判断电力电缆的老化。在研究中，研究了由于捕获载流子而产生的剩余电压的特性。提出了一种确定捕获载流子数量和平均位置的新方法。并对聚乙烯（PE）薄膜进行了测试。此外，还开发了新的简单的残余电压技术来判断绝缘体中被困载流子的极性和测量电荷分布。在剩余电压测量中，给出绝缘子两个电极之间的温度差。因此，被困载流子的脱陷特性取决于位置，从而获得载流子的空间信息。这些测量结果对判断电力电缆的劣化性能有一定的参考价值。

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.