CAJ | 학술논문

换流变压器内电场以交直流叠加电场为主,与交流变压器有明显区别,因此其局部放电和产气特性与交流变压器不同,已有的交流诊断依据不适用于换流变压器,需要重新对判定依据进行总结。搭建了一套交直流复合电压作用下油纸绝缘针板放电试验平台,通过分析放电特征的时间变化趋势及统计规律,总结不同时间的产气特性,得到了适用于换流变压器的诊断依据。研究结果表明：交直流复合电压作用下放电和产气特性表现出明显的阶段特征,整个过程可以划分为3个阶段：放电起始阶段、发展阶段及临近击穿阶段；根据局部放电和产气特性的规律及趋势可以作为换流变压器针板放电阶段的判定依据,即脉冲重复率很小,烃类气体产出极少为起始阶段；脉冲重复率明显增加, CH4产出量大为发展阶段；绝对产气速率超过0．5 mL/h, C2 H2产出量最大,且出现C2 H6时为临近击穿阶段。
환류변압기내전장이교직류첩가전장위주,여교류변압기유명현구별,인차기국부방전화산기특성여교류변압기불동,이유적교류진단의거불괄용우환류변압기,수요중신대판정의거진행총결。탑건료일투교직류복합전압작용하유지절연침판방전시험평태,통과분석방전특정적시간변화추세급통계규률,총결불동시간적산기특성,득도료괄용우환류변압기적진단의거。연구결과표명：교직류복합전압작용하방전화산기특성표현출명현적계단특정,정개과정가이화분위3개계단：방전기시계단、발전계단급림근격천계단；근거국부방전화산기특성적규률급추세가이작위환류변압기침판방전계단적판정의거,즉맥충중복솔흔소,경류기체산출겁소위기시계단；맥충중복솔명현증가, CH4산출량대위발전계단；절대산기속솔초과0．5 mL/h, C2 H2산출량최대,차출현C2 H6시위림근격천계단。
The AC/DC superimposed electric field in converter transformer is quite different from AC transformer, resulting in differ-ent partial discharge and dissolved gases in oil. The existing diagnosis bases are not suitable for converter transformer, and need to be updated. A set of test platform for needle-plate model under AC and DC combined voltage is built to analyze the trend and statistical laws of discharge characteristics as well as to summarize the feature of dissolved gas in oil. The results show that the characteristics of discharge and dissolved gas in oil under AC/DC superimposed voltage interaction have distinct differences with 3 stages changing, namely, the inceptive stage, the developing stage and the imminent breakdown stage. The pattern and trend of partial discharge and dissolved gas in oil can be used as the diagnostic basis for converter transformer, wherein during the inceptive stage, the repetition of pulse is very small with very little hydrocarbon gas discharge, during the developing stage, the repetition of pulse increase dramatically with CH4 as the main portion of the hydrocarbon gas discharge, during the imminent breakdown stage, the absolute hydrocarbon gas discharge exceeds 0. 5mL/h with C2 H2 as the main portion, and C2 H6 will be detected at this stage.