交直流复合电压下油纸绝缘气隙放电模型油中溶解气体诊断  

Diagnosis of DGA for Air-gap Discharge Model in Oil Paper Insulation Under AC-DC Composite Voltage

作　　者：张书琦[1] 苑清[2] 齐波[3] 赵志刚[1] 刘雪丽[1] ZHANG Shuqi;YUAN Qing;QI Bo;ZHAO Zhigang;LIU Xueli(China Electric Power Research Institute,Beijing 100192,China;Beijing Key Laboratory of High Voltage and Electromagnetic Compatibility,North China Electric Power University,Beijing 102206,China;State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources,North China Electric Power University,Beijing 102206,China)

机构地区：[1]中国电力科学研究院,北京100192 [2]华北电力大学高电压与电磁兼容北京市重点实验室,北京102206 [3]华北电力大学新能源电力系统国家重点实验室,北京102206

出　　处：《华北电力大学学报（自然科学版）》2019年第3期50-56,65,共8页Journal of North China Electric Power University：Natural Science Edition

基　　金：国家重点研发计划项目(2017YFB0902704);国家电网公司科技项目(GYB17201500159)

摘　　要：换流变压器作为直流输电工程的核心设备,其运行可靠性直接影响整个电网安全运行的稳定性,但直流电压的加入是否会导致油纸绝缘产气特性变化,影响故障诊断结果还需进一步确认。针对该问题搭建了模拟换流变压器实际运行工况的平台并进行试验。试验分别在交流电压和不同比例交直流复合电压下,采用气隙放电模型,对油纸绝缘局部放电油中溶解气体进行了研究。研究结果表明:气隙放电模型在交流电压下油中溶解气体主要以H_2为主,在交直流电压复合电压下则以C_2H_6和CH_4为主;局部放电起始阶段的诊断中,交流电压下通过油中溶解气体可以诊断得到低能放电故障,但交直流复合电压下无法得到故障结果;局部放电临近阶段交流电压下诊断结果均为电弧放电,而交直流复合电压下50%的诊断结果为低能放电。气隙模型在交流和交直流复合电压下油中溶解气体存在明显区别,导致诊断结果不同。因此运用改良三比值法对换流变压器故障诊断还需要进一步优化。The converter transformer is the core equipment of the HVDC,and its normal operation directly guarantees the stability of the entire power grid.However,there is some doubt whether DC voltage will change the gas generation characteristics of the transformer oil-paper insulation,thus affecting the fault diagnosis of converter transformer.In this paper,a platform to simulate the actual operation condition of converter transformer was built and tested.This paper also took an air-gap discharge model to conduct dissolved gas analysis(DGA)of partial discharge in oil-paper insulation under AC and AC-DC composite voltages of different proportions.Here are the study results:(1)the dissolved gas in the air-gap discharge model is mainly H2 under AC voltage,but it is mainly C2 H6 and CH4 under AC-DC composite voltage;(2)in the initiation stage of partial discharge,the DGA detects the low energy discharge under the AC voltage,but it cannot detect the cause of the faults under AC-DC composite voltage;(3)in the approach stage of partial discharge,faults are all diagnosed as results of arc discharge under AC voltage,but 50%of the fault diagnoses blame to low energy discharge under AC-DC composite voltage.The air-gap discharge model gives rise to different DGA and fault diagnoses under AC and AC-DC composite voltage,therefore,the three-ratio method of diagnosing the faults of converter transformer should be further improved.

关 键 词：油纸绝缘 交直流复合电压 气隙放电模型 溶解气体分析 故障诊断 

分 类 号：TM8[电气工程—高电压与绝缘技术]