Evaluation of Electrical Tree Degradation in Cross-Linked Polyethylene Cable Using Weibull Process of Propagation Time

Donguk Jang,Seonghee Park

doi:10.3390/en10111789

Abstract

The main purpose of this paper is to evaluate electrical tree degradation for cross-linked polyethylene (XLPE) cable insulation for three difference models. In order to show the distribution characteristics using phase resolved partial discharge (PD), we acquire data by using a PD detecting system. These acquired data presented four 2D distributions such as phase angle-average discharge distribution, pulse magnitude-pulse number distribution, phase angle-pulse number distribution, and phase angle-maximum discharge derived from the distribution of PD. From the analysis of these distributions, each of the tree models are proved to hold its unique characteristics and the results were then applied as basic specific qualities. In order to evaluate the progresses of an electrical tree, we proposed methods using parameters by means of Weibull distribution to the time of tree propagation. We measured the time of tree propagation for 16 specimens of each artificial tree models from initiation stage, middle stage, and final stage respectively, using these breakdown data, we estimated the shape parameter, scale parameter, and mean time to failure. It is possible to analyze the difference in lifetime between the initial stage, the middle stage, and the final stage, and could be used to predict the lifetime of an XLPE cable from these results.

Highlights

Maintenance technology for diagnosing electric power equipment has shifted from time-based maintenance to both condition-based and reliability-centered maintenance in Korea
Several methods to classify partial discharge (PD) sources or insulation diagnosis were proposed like fuzzy theory, artificial neural network (ANN), fractal model, statistical diagnosis were proposed like fuzzy theory, artificial neural network (ANN), fractal model, statistical methods, and backpropagation
This paper analyzed the electrical tree propagation-based characteristics of the distributions of partial discharge signals occurring in cable insulation materials and has presented a degradation evaluation method, the results of this study are as follows: 1

Summary

Introduction

Among various methods of implementing condition-based diagnosis, partial discharge (PD) diagnosis method is most widely used because it is easy to derive parameters for insulation diagnosis. This is thanks to sufficient information on the insulation condition of the electric power equipment that is contained in signals arising from the occurrence of PD in the power equipment [1,2]. Whereas insulated cables are rarely utilized in the general sections of electric railroads due to the overhead catenary lines being used there, the minimalized construction of insulated cables in tunnel sections is operated from the perspective of the cross-sectional area of a tunnel on the grounds of construction costs. Feeder wires are installed inside tunnels as insulated cables on overhead catenary lines. The condition diagnosis and degradation evaluation of the insulated cables installed in tunnels emerge as important factors

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