500 kV變壓器無勵磁分接開關(guān)放電故障診斷分析
丁凱，李文燕，張翾喆，劉昌標，周杰，謝斯晗
(國網(wǎng)浙江省電力公司超高壓分公司，浙江 杭州 311232)
摘 要：無勵磁分接開關(guān)出現(xiàn)放電性故障會嚴重危害變壓器安全運行。介紹了一起 500 kV 變壓器交接試驗過程中脈沖局部放電試驗異常的案例，應用脈沖電流法、特高頻法、超聲波法等多維局部放電檢測技術(shù)進行時差定位，成功診斷了變壓器無勵磁分接開關(guān)內(nèi)部異物放電故障；通過材質(zhì)成分分析判斷異物為動觸頭旋轉(zhuǎn)軸壓環(huán)的機加工碎屑，異物位于無勵磁分接開關(guān)動觸頭旋轉(zhuǎn)軸位置，隨擋位切換而移動，導致各個擋位均可檢測到局部放電，且脈沖局部放電量隨擋位變化而變化。
關(guān)鍵詞： 變壓器；無勵磁分接開關(guān)；局部放電；脈沖電流法；特高頻法；超聲波法；時差定位；異物放電故障
中圖分類號：TM403.4 文獻標識碼：B 文章編號：1007-3175(2024)06-0049-05
Fault Diagnosis and Analysis of 500 kV Transformer
Non-Excitation Tap-Changer Discharge
DING Kai, LI Wen-yan, ZHANG Xuan-zhe, LIU Chang-biao, ZHOU Jie, XIE Si-han
（State Grid Zhejiang Electric Power Company Ultra High Voltage Branch, Hangzhou 311232, China）
Abstract: The discharge failure of the non-excitation tap-changer will seriously endanger the safe operation of the transformer. In this paper, a case of abnormal pulse partial discharge test during the handover test of 500 kV transformer is introduced, and the multi-dimensional partial discharge detection technologies such as pulse current method, ultra-high frequency method, and ultrasonic method are used to locate the time difference, and the internal foreign body discharge fault of the transformer,s non-excitation tap-changer is successfully diagnosed.Through the analysis of material composition, it is judged that the foreign body is the machined debris of the rotating shaft pressure ring of the moving contact, and the foreign body is located at the position of the rotating shaft of the moving contact of the non-excitation tap-changer and moves with the gear switching, resulting in partial discharge being detected in each gear, and the amount of pulse partial discharge changes with the change of gear.
Key words: transformer; non-excitation tap-changer; partial discharge; pulse current method; ultra-high frequency method; ultrasonic method; time difference localization; foreign body discharge fault
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