基于PDC的多应力老化乙丙橡胶电缆绝缘状态评估

State Evaluation of Multi-stress Aged EPR Cable Insulation Based on PDC

为了能准确地评估乙丙橡胶电缆的绝缘老化状态,搭建了多应力加速老化试验系统。测量了不同老化周期后电缆试样绝缘的极化与去极化电流,通过等温松弛理论和扩展德拜模型分别提取了老化因子A和低频介质损耗因数(tanδ0.1 Hz)来评估电缆绝缘的老化状态。结果表明:老化因子A与tanδ0.1 Hz对表征乙丙橡胶电缆绝缘的劣化状况具有很好的一致性。随着老化程度的加深,老化因子A呈指数增长规律,tanδ0.1 Hz也逐渐增大。由PDC法得到的老化因子A和tanδ0.1 Hz都能较好地评估乙丙橡胶电缆的绝缘状态。

In order to accurately evaluate the state of ethylene-propylene rubber cable insulation,a multiple-stress accelerated ageing test system was built.The polarization and depolarization current of the cable insulation after ageing for different cycles were measured.The ageing state of cable insulation was evaluated by the ageing factor A and the low frequency dielectric loss factor(tanδ0.1Hz),which extracted by the isothermal relaxation theory and the extended Debye model.The results show that the ageing factor A and tanδ0.1Hz are consistent in characterizing the degradation state of ethylene-propylene rubber cable insulation.With the increase of ageing degree,the ageing factor A increases exponentially,and the tanδ0.1Hz increases gradually.Therefore,the ageing factor A and tanδ0.1Hz obtained by the PDC method can better evaluate the state of ethylene-propylene rubber cable insulation.