极化去极化电流法极化参量对电力电容器绝缘状态的影响

Effect of Polarization Parameters of Polarization － Depolarization Current Method on Insulation State of Power Capacitors

摘要:

电力电容器用途广泛，是电力系统中重要的一次设备。针对目前电力电容器绝缘状态检测欠缺成熟高效的 手段，提出一种基于极化去极化电流法来检测电力电容器的绝缘状态，并分析极化去极化电流法中极化电压和极化 时间对绝缘状态判断的影响。首先阐述了极化去极化电流法的基本原理，其次利用测试的极化去极化电流推导出决 定电容器绝缘状态的两个特征参量，即直流电导率和 0． 1 Hz 介损; 再基于该方法理论，研究出在不同极化电压和不同 极化去极化时间下，电力电容器极化、去极化电流都有不同程度的差异，但其绝缘状态参量直流电导率和 0． 1 Hz 介损 却没有发生显著的变化。通过研究说明利用极化去极化电流法能够无损检测电力电容器的绝缘状态。

Abstract:

Power capacitors are widely used in power system and are the important primary equipment in power system． At present，there is a lack of mature and efficient means to detect the insulation state of power capacitors． So a method based on polarization － depolarization current is proposed to detect the insulation state of power capacitors． The influence of polarization voltage and polarization time in polarization － depolarization current method on the judgment of insulation state is analyzed． The basic principle of polarization － depolarization current method is described，and then two characteristic parameters are deduced，namely DC conductivity and dielectric loss at 0． 1 Hz，which determine the insulation state of capacitors by using the measured polarization － depolarization current． Based on the theory of this method，the polarization and depolarization current curves of power capacitors under different polarization voltage and different depolarization time are studied． The test results show that the polarization and depolarization currents of power capacitors vary under different polarization voltage and time，but DC conductivity and dielectric loss at 0． 1 Hz do not change significantly． It shows that the polarization － depolarization current method can detect the insulation state of power capacitors nondestructively．