應用脈衝電流法於電力電纜故障測距之研究

A Study of Using Impulse Current Method in Power Cable Fault Location

王世榮(Shih-Jung Wang)

指導教授 ： 曾國雄

國立臺北科技大學/機電學院/電機工程系所/碩士(2007年)

https://doi.org/10.6841/NTUT.2007.00315

摘要

利用電力電纜傳輸電力具有較高的安全性和可靠度，不僅可增加供電品質，更具有美化市容景觀的功能，不過當電力電纜發生故障時，因其大都埋設於地下，所以故障點位置的尋找變得相當困難。因此，如何準確地定位出電力電纜故障點的位置，是一個很重要的課題。
本文將對電力電纜故障發生的原因和類型進行概述，並分析各種電力電纜故障測距的方法。且以實務性的探討為主，應用目前使用最廣泛的脈衝電流法，針對配電系統25KV級 XLPE 500MCM電力電纜進行故障點距離的現場實測，討論該方法適用和局限的情形，並且參照國內配電系統多重接地方式之電力電纜設置架構，進行各種電力電纜故障類型之測距模擬與結果分析，探討影響故障測距準確性的各種因素。
故障點電流反射係數的大小將是影響線性耦合器輸出圖形辨識度的主要關鍵，而故障點電流反射係數取決於電力電纜故障的狀態，多重接地系統之接地電阻大小雖不影響故障測距的準確性，但會因故障點電流反射係數的改變，間接影響輸出圖形的複雜度。而當故障點電流反射係數過小時，利用小波分析進行電力電纜故障測距後的信號檢測，將可使故障測距的結果更加準確和穩定，並使其精準度達到 1%，對故障測距結果具有相當大的助益。

關鍵字

電力電纜 ； XLPE ； 故障測距 ； 脈衝電流法 ； 多重接地 ； 小波分析

並列摘要

Utilizing the power cable to transmit the electricity has higher security and reliability. It can not only increase the quality of supplying power, but also beautify the view of the city. Since the power cable is mostly installed under the ground, it will become quite difficult to seek the position of the fault when the power cable breaks down. Therefore, how to locate the position of the fault accurately is a very important subject.
First, This paper summarizes the causes and types of the power cable fault, and analyzes the various methods of the power cable fault location. Then, with taking practice discussion as the core, the position of the fault power cable , 25KV XLPE 500MCM power cable of the distribution, is located in a work field by using the impulse current method which is the most popular manner at present and the suitable and limitable situations of the method are conferred. Finally, according to the installed structure of domestic multi-grounded distribution, this paper simulates and analyzes the power cable fault location with various fault types and probes into the factors that influence the accuracy.
The current reflection coefficient of the fault point is the main key to influence the identification of the output figure of the linear coupler and it depends on the state of the fault. The magnitude of multi-grounded resistance doesn’t influence the accuracy of the power cable fault location, but the change of the current reflection coefficient of the fault point will influence the complexity of the output figure indirectly. If current reflection coefficient of fault point is too little to distinguish the output figure, applying wavelet analysis to detect the signal after measuring can improve the result of the power cable fault location to be more accurate and stable, and the precision of the result is up to 1%. It is very helpful for the power cable fault location.

並列關鍵字

Power cable ； XLPE ； Fault location ； Impulse current method ； Multi-grounded ； Wavelet analysis

參考文獻

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