摘要交联聚乙烯（XLPE）电力电缆由于其电气机械性能良好、工艺简便、安装维护方便 等优点，在我国的应用日益广泛，尤其在 6KV 及以上电压等级的供配电系统中。但当 XLPE 电缆使用一定年限以后，常常会因电缆绝缘状态往下降而造成事故，而且每次事故都可 能造成巨大的经济损失，故电缆绝缘在线监测显得尤为重要。水树枝在电缆绝缘劣化中 所占比例较大，且直流叠加法对水树枝很敏感。针对这一现状，本文采用正反直流叠加 法设计一套针对 10KV 电压等级的 XLPE 电缆绝缘在线监测装置，通过求 XLPE 电缆绝缘 电阻来判断电缆的绝缘状态。该方法不仅消除了水树枝整流效应等对测量精度的影响， 而且考虑了电缆对地分布电容，提高了检测速度。通过软件仿真证明了该方法的有效性。80404

毕业论文关键词 XLPE 电缆 水树枝 绝缘状态 在线监测 正反直流叠加

Title On-line Monitoring of XLPE Power Cable Insulation Based on DC Superposition Method

Abstract Cross linked polyethylene (XLPE) power cable has good electrical and mechanical performance。 It has simple process and it is easy to install and maintain, therefore it is widely used in electric power system, especially in the power supply and distribution system of 6KV and above voltage level。 But When the XLPE cable is used after a certain period of time, the cable insulation state down and often cause accident, and each accident may cause huge economic losses, so the cable insulation online monitoring is particularly important。 Because of the large proportion of the reasons for the deterioration of the cable, and the DC superposition method is very sensitive to the water branch。 According to the current situation, in this paper, a on-line monitoring device for an XLPE cable insulation in 10KV voltage level is designed by using the positive and negative DC superposition method。 This system eliminates the influence of water tree rectification effect on the measurement accuracy, and considers the distribution of cable capacitance, improves the detection speed。 The validity of this method is proved by software simulation。

Keywords XLPE power cable Insulation state on-line monitoring DC superposition method water tree

目 次

1 引言 1

1。1 课题研究背景 1

1。2 XLPE 电力电缆及其劣化机理 1

1。3 本文主要研究内容 2

2 直流叠加法 3

2。1 直流叠加法基本测量原理 3

2。2 正反直流叠加法监测方法 4

3 电力电缆水树枝简介 6

3。1 电缆水树枝概述 6

3。2 电缆水树枝模型 7

4 硬件系统设计及实现