洩漏電流及部份放電對氧化鋅避雷器之影響分析

The Effects of Leakage Current and Partial Discharge on Zinc Oxide Arresters

魏子喬(Zih-Ciao Wei)

指導教授 ： 曾國雄

國立臺北科技大學/電資學院/電機工程系 電力科技系統產業研發碩士專班/碩士(2009年)

摘要

電力系統當中數量最龐大的避雷器為配電級避雷器，安裝的環境最複雜也最惡劣，其不若變電所等級避雷器般可以容易實施線上監測作業，即時掌握運轉狀況，以防範事故於未然。因此本論文以台灣目前11.4kV和22.8kV配電系統所使用的額定電壓分別為9kV及18kV之配電級避雷器為研究對象，於離線情況下使用高壓交流電壓源供應器分別對9kV和18kV配電級避雷器測試樣品進行加壓量測洩漏電流值，再輔以直流電壓源及衝擊電流設備分別實施參考電壓及殘餘電壓試驗，最後使用高壓交流電源供應器、法拉第遮蔽室和部份放電檢測器量測部份放電量，進而分析洩漏電流、直流參考電壓、殘餘電壓三者之間的關係，及洩漏電流、部份放電對避雷器所產生的影響。研究結果顯示：（1）當試驗電壓高於額定電壓的1.1倍後，電阻性洩漏電流呈現直線上升趨勢，且舊品比新品的情況嚴重。（2）殘餘電壓是避雷器保護性能的參考指標，不同廠牌間，殘餘電壓與洩漏電流無絕對關係，不能以洩漏電流的高低來判定保護性能優劣。（3）相同廠牌的避雷器，直流參考電壓新品高於舊品，直流參考電壓愈高則殘餘電壓愈低；反之則殘餘電壓愈高，所以直流參考電壓能確實反應劣化。（4）部份放電出現於電壓峰值處，由於電力計取樣速率關係，洩漏電流顯示值無明顯飄移，但會對絕緣產生不良影響。（5）避雷器於受潮後，除了產生部份放電對絕緣造成破壞之外，於正常電壓下的電阻性洩漏電流大幅增加，往後在絕緣及過熱雙重影響之下，將可能導致避雷器炸毀。藉由本研究的成果，期可作為配電級氧化鋅避雷器預防性維護之參考。

關鍵字

氧化鋅避雷器 ； 洩漏電流 ； 最高連續運轉電壓 ； 殘餘電壓 ； 部份放電

並列摘要

Distribution class arresters are mainly used in the power system and installed in the most complicated and adverse environments. Unlike station class arresters, distribution class arresters can not be used for on-line effective monitoring and real-time operation control, preventing accidents in advance. The research focus of this article are distribution class arresters of 9kV and 18kV, which were performed the off-line leakage current test individually by the AC high voltage supply, as well as the DC reference voltage test by the DC power supply, and residual voltage test by the impulse current generator; Finally, to measure the partial discharge by the AC high voltage supply, Faraday Effect shielding room and partial discharge detector, then analyzing the relations among leakage current, DC reference voltage and residual voltage, and the effects of leakage current and partial discharge to arresters. The research indicates: (1) when the test voltage goes beyond 1.1 times rated voltage, the resistive leakage current would demonstrate growth in a straight line and this phenomenon would become more severe in the used arresters than the brand new. (2) residual voltage is a reference index on the protection performance of the arrester and there is no absolute connection between residual voltage and leakage current for the different makers, it would be less probable to determine the performance of protection by measuring the level of leakage current. (3) the arresters which made by the same maker, a new arrester would show higher DC reference voltage than an used one and the higher the DC reference voltage goes, the lower the residual voltage becomes, on the contrary, the higher would be the residual voltage, so DC reference voltage is an ideal indication for deterioration. (4) partial discharge occurs in peak voltages, because of the sampling rate of the power meter, there are no apparent offset on the leakage current display value, but partial discharge will make negative effects on insulation. (5) when arresters dampened, the partial discharge will damage the insulation, in addition the resistive leakage current under normal voltage will grow significantly, then arresters might even explode. From the research results, they are considered beneficial for the preventive maintenance of distribution class zinc oxide arresters.

並列關鍵字

Metal Zinc Oxide Arresters(MOA) ； Leakage Current ； Maximum Continuous Operating Voltage(MCOV) ； Residual Voltage ； Partial Discharge(PD)

參考文獻

[23]陳世榮，氧化鋅避雷器之維護及線上監測技術，碩士論文，私立中原大學電機工程研究所，桃園，2005。

[5]Y. Harumoto, Y. Tsuda, M. Kobayashi, M. Mizuno, and T. Aoki, "Evaluation for Application of Built-In Type Zinc Oxide Gapless Surge Arresters for Power System Equipments," IEEE Transactions on Power Delivery, vol. 2, no. 3, July 1987, pp. 750-757.

[7]M. Kobayashi, M. Mizuno, T. Aizawa, M. Hayashi, and K. Mitani, "Development of Zinc-Oxide Non-Linear Resistors and Their Application to Gapless Surge Arresters," IEEE Transactions on Power Apparatus and Systems, vol. 97, no. 4, July 1978, pp. 1149-1158.

[8]A. Mizukoshi, J. Ozawa, S. Shirakawa, and K. Nakano, "Influence of Uniformity on Energy Absorption Capabilities of Zinc Oxide Elements as Applied in Arresters," IEEE Transactions on Power Apparatus and Systems, vol. 102, no. 5, May 1983, pp. 1384-1390.

[9]K. Mukae, K. Tsuda, and S. Shiga, "Zinc Oxide-Praseodymium Oxide Elements for Surge Arresters," IEEE Transactions on Power Delivery, vol. 3, no. 2, April 1988, pp. 591-598.