基于冲击介电响应法的电力电缆绝缘状态评估

为了解决传统频域介电谱法在电缆绝缘测试中的不足,提出一种基于冲击电压的介电响应法用于评估电缆绝缘状态。首先从理论上对冲击介电响应法进行推导,然后从仿真角度分析用该方法评估电缆绝缘状态的可行性,最后搭建了冲击实验平台,并对不同老化时长的短电缆样本进行测试。结果表明:冲击介电响应法能够反映出电缆在较宽频率范围下的介质损耗变化,老化电缆的介质损耗因数随着频率升高出现回升现象,且随老化时间的增加其回升程度更为明显。研究结果表明冲击下的介电响应特征能有效评估电缆的绝缘老化状态。

Insulation State Assessment of Power Cables Based on Impulse Dielectric Response Method

In order to solve the shortcomings of traditional frequency domain dielectric spectrum method in cable insulation testing,a dielectric response method based on impulse voltage was proposed to evaluate the cable insulation state.The impulse dielectric response method was deduced theoretically at first,and then the feasibility of this method to evaluate the cable insulation state was analyzed by simulation.Finally,an impact test platform was built,and the short cable samples aged for different time were tested.The results show that the impulse dielectric response method can reflect the change of dielectric loss in a wide frequency range,the dielectric loss factor of the aged cable appears a recovery process with the increase of frequency,and the recovery degree is more obvious with the increase of ageing time.It is concluded that the dielectric response characteristics under impulse can effectively evaluate the ageing state of cable insulation.