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

在向绝缘体施加直流电压之后，在开路中观察到绝缘体的残余电压。近年来，人们已经知道直流电力电缆的残压取决于电缆的劣化程度，因此，测量电缆残压被认为是判断电缆劣化的有效方法之一，本文研究了一种快速测量空间电荷来判断电缆劣化的方法。在研究中，由于捕获的电荷载流子的剩余电压的特性进行了研究。本文提出了一种确定俘获载流子数量和平均位置的新方法。并对聚乙烯（PE）薄膜进行了测量。此外，还发展了一种新的简单的剩余电压技术，用于判断绝缘体中俘获电荷载流子的极性和测量电荷分布。在剩余电压的测量中，给出了绝缘体两电极间的温差，因此，被俘获载流子的脱陷特性取决于位置，从而获得了载流子的空间信息。这些测量结果可用于判断电缆的老化程度。

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.