一起變電站直流串入交流回路的異常分析與處理
申濤
（國網浙江省電力公司檢修分公司，浙江 杭州 310000）
摘 要：針對某500 kV 變電站2 號主變復役操作過程中，當拉開2 號主變220 kV 側接地閘刀后，出現直流接地報警，合上該接地閘刀，直流接地告警消失的異常情況，經過分析查找，發現與該主變220 kV側接地閘刀有聯閉鎖關系的2 號主變2 號電容器3221 閘刀機構箱內的熱繼電器F1 兩副接點間內絕緣異常，導致直流串入閘刀交流控制回路。闡述了具體的故障處理過程，并給出了變電站在設計、施工、運維過程中防止直流接地的注意事項。
關鍵詞：直流接地；熱繼電器；直流串交流；閉鎖邏輯
中圖分類號：TM631 文獻標識碼：B 文章編號：1007-3175(2016)07-0027-03
Abnormal Analysis and Processing of a Direct Current String into
Alternating Current Circuit in Substation
SHEN Tao
（State Grid Zhejiang Maintenance Company, Hangzhou 310000, China）
Abstract: In the process of #2 main transformer recommision operation of certain 500 kV substation, after the grounding switch blade of #2 main transformer at 220 kV side was pulled open, the direct current grounding alarm occurred; while the grounding switch blade of #2
main transformer was closed, the direct current grounding alarm disappeared. After analysis and search, the abnormal insulation between two pairs of contact in thermal relay F1 was the cause of alarm events in 3221 switch blade operation box of #2 main transformer, which has electric locking relationship with the grounding switch blade at 220 kV side. The concrete fault treating procedure was expounded. This paper gave the matters need attention to prevent direct current grounding in the process of substation design, construction, operation and maintenance.
Key words: direct current grounding; thermal relay; direct current string into alternating current; blocking logic
參考文獻
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