乙丙橡胶表面电痕腐蚀对极化——去极化电流的影响

Effect of Surface Electrical Tracking of Ethylene Propylene Rubber on Polarization-depolarization Current

电痕是引起绝缘表面劣化的主要原因之一。针对矿用乙丙橡胶电缆绝缘表面电痕腐蚀问题,文中以不同电痕发展阶段的乙丙橡胶试样为研究对象,试验测量并分析了乙丙橡胶表面电痕腐蚀程度与极化—去极化电流之间的关系,提取了去极化初始电流值、电流衰减稳定值和凹点出现时间3个特征量。对比不同电痕腐蚀程度试样的极化—去极化电流曲线及其特征量发现:在去极化初始阶段,初始电流值、放电速率和去极化电流衰减稳定时刻的电流值与乙丙橡胶表面电痕损伤程度密切相关;随着测量时间的延长,去极化电流曲线上出现凹点,该凹点出现时间与表面电痕腐蚀程度相关。研究结果证明,使用极化去极化电流方法可以对乙丙橡胶的表面电痕腐蚀程度进行有效评估。

Electrical tracking is one of the main reasons for the deterioration of insulation surface. According to the problem of the surface electrical tracking erosion of insulation using in the high-voltage mining cables, the ethylene propy lene rubber samples with different electrical tracking development stage are selected in the paper. The relationship between the surface electrical tracking erosion degree of ethylene propylene rubber and polarization-depolarization current is analyzed. Characteristic parameters, which include the initial value of depolarization current, the static value of current attenuation and the time of concave point, are extracted from the depolarization current curves. Comparing the depolarization curves of surface electrical tracking erosion degree of different samples and its characteristic parameters, it has been found that the initial value of depolarization current, the static value of current attenuation and the time of concave point are closely related to the electrical tracking development stage. The concave point can be observed with the increase of measuring time, which relates to the degree of surface electrical tracking erosion. Research results demonstrate that the severity degree of electrical tracking erosion can be discriminated with polarization-depolarization current.