一起500 kV變壓器中性點(diǎn)套管介損超標(biāo)原因分析及處理
謝斯晗,張翾喆,李文燕,艾云飛,劉昌標(biāo)
(國(guó)網(wǎng)浙江省電力有限公司檢修分公司,浙江 杭州 311232)
摘 要:在某500 kV變電站進(jìn)行例行停電試驗(yàn)時(shí)發(fā)現(xiàn)主變中性點(diǎn)套管介損超標(biāo),現(xiàn)場(chǎng)綜合絕緣油色譜、微水、絕緣電阻試驗(yàn)初步確認(rèn)了導(dǎo)致介損增大的原因。套管返廠試驗(yàn)時(shí)發(fā)現(xiàn)介損較現(xiàn)場(chǎng)測(cè)試結(jié)果有進(jìn)一步的增大,通過密封性試驗(yàn)、絕緣油色譜、微水試驗(yàn),結(jié)合套管的解體檢查,確定套管介損超標(biāo)的原因是套管油枕放氣孔螺栓未旋緊導(dǎo)致受潮,返廠后介損進(jìn)一步增大的原因是運(yùn)輸過程中套管底部水分?jǐn)U散至整個(gè)電容屏,對(duì)如何預(yù)防類似情況發(fā)生給出了若干建議。
關(guān)鍵詞:中性點(diǎn)套管;介損;電容量;微水試驗(yàn);受潮
中圖分類號(hào):TM406 文獻(xiàn)標(biāo)識(shí)碼:B 文章編號(hào):1007-3175(2019)11-0042-03
Analysis and Processing of Excessive Dielectric Loss Value in 500 kV Transformer Neutrality Point Bushing
XIE Si-han, ZHANG Xuan-zhe, LI Wen-yan, AI Yun-fei, LIU Chang-biao
(Maintenance Branch of State Grid Zhejiang Electric Power Company Ltd, Hangzhou 311 232, China)
Abstract: It found that the dielectric loss value of transformer neutrality point bushing is out of limits when the routine power test conducted in a 500 kV transformer substation, the integrate oil chromatography, the micro water test and the insulation resistance test were preliminarily verified to be the reason of increscent abnormal dielectric loss value in working site. The dielectric loss value increased further than the result of test in working site when the transformer neutrality point bushing was backed to the manufacturers. The encapsulation test, the oil chromatographic test, the micro water test and the strip inspection of bushing verified that the reasons of trouble were the damp caused by the loose air-bleed hole bolt of the oil breather and the water at the bottom of bushing diffusing into capacitive screen in the process of transportation. This paper has offered some suggestion to avoid the similar situation.
Key words: neutrality point bushing; dielectric loss value; capacitance; micro water test; damp
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