基于超低频介损的XLPE电缆绝缘受潮检测判据研究

电缆超低频介损测试技术在国内刚刚起步,所采用的IEEE Std 400.2-2013超低频介损判据并不完全适用于我国本土化XLPE电缆,开展电缆超低频介损检测的研究迫在眉睫。因此,本文通过加速水树老化实验验证超低频介损检测对于水树劣化检测的有效性,并开展现场测量,对所测252组数据进行状态分级,发现介损变化率为负的电缆线路处于注意或异常状态,多处于异常状态;且介损的波动值可更加清晰直观反映电缆运行状态。因此,在现有的电缆超低频介损三大判据之外,提出了新的特征量反向介损变化率和介损极差,吸纳韩国Skirt介损判据,最终形成更为完善的超低频介损检测判据体系,为我国配网电缆超低频介损老化状态评价规程的制定提供了参考。#$NL关键词：XLPE电缆;超低频介损;电缆水树;检测判据;反向介损变化率;介损极差#$NL中图分类号：TM854

Detection criterion of XLPE cable insulation based on very low frequency dielectric loss

T he cable very low frequency dielectric loss (VLF-TD) test technology has just started in China. The IEEE Std 400.2-2013 VLF-TD criterion is not fully applicable to China"s localized XLPE cable. It is extremely urgent to carry out research on cable VLF-TD test. Therefore, this paper verifies the effectiveness of VLF-TD test for water tree degradation detection by accelerating water tree aging test. And carry out on-site measurement, and classify the 252 sets of data measured. It is found that the cable line with a negative dielectric loss rate is in a state of attention or abnormality, and is mostly in an abnormal state. And the fluctuation value of the dielectric loss can more clearly and intuitively reflect the running state of the cable. Therefore, in addition to the three existing criteria of VLF-TD, the new characteristic quantity reverse dielectric loss change rate(RDTD) and extreme difference of dielectric loss (ETD) are proposed, and the Korean Skirt dielectric loss criterion is absorbed, which is finally improved. The VLF-TD test criterion system provides a reference for the formulation of the VLF-TD aging state evaluation procedure for distribution cables in China.#$NLKeywords: XLPE cable; Very low frequency dielectric loss(VLF-TD); Cable water tree; Detection criteria; Reverse dielectric loss rate(RDTD); Extreme difference of dielectric loss (ETD)