Characteristics of Interface Charge on Oil-paper Surface Insulation Under Polarity Reversal Voltage
陈义龙1, 齐波2, 李成榕2
1. 广东电网公司电力科学研究院,广州510080
2. 华北电力大学新能源电力系统国家重点实验室,北京102206
CHEN Yilong1, QI Bo2, LI Chengrong2
1. Electric Power Research Institute of Guangdong Power Grid Corporation, Guangzhou 510080, China
2. State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources, North China Electric Power University, Beijing 102206, China
:When the power reversal or voltage-suddenly-change situation appears in the HVDC system, the oil-paper insulation of converter transformer will withstand polarity reversal voltage, which often tends to cause the insulation failure. In order to study the charge characteristics of the oil-paper insulation, the changes of the oil-paper interface electric density in this process were studied based on electrostatic capacitive probe measurement. It is found that the oil-paper interface charge can strengthen the transient electric field at the time of the polarity inversion of the external voltage, and the degree of reinforcement is proportional to the density of the interface charge of the reservoir. The interface charge accumulation time of the surface insulation structure is different from parallel insulation structure remarkably, and the uneven distribution of the electric field is strengthened by the polarity reversal voltage. It is recommended that the voltage abrupt waveform of the CIGRE (reverse time <2 ms) can be adopted as the test for the production test of converter transformer. These conclusions are of great significance to improving the insulation design and the reliability of the converter transformer.
图12
IEC 61378-2标准极性反转试验界面电荷密度的变化
Fig.12
Interface electric density changes of oil-impregnated pressboard according to IEC 61378-2
图13
IEC 61378-2标准极性反转试验表面电位与外施极化电压的关系
Fig.13
Relationship of surface potential and polarization voltage according to standard IEC 61378-2 polarity reversal test
表1
界面电荷产生的表面电位与外施电压的关系
Table
1 Relationship between the surface potential of the interface charge and the external voltage
图14
外施电压由正极性反转负极性过程界面电荷
变化示意图
Fig.14
Interface charge changes of oil-impregnated pressboard in the process of reversing positive polarity to negative polarity
图15
外施电压由8 kV反转到-8 kV过程中界面电荷 密度变化细节
Fig.15
Interface charge changes in the details of oil-impregnated pressboard while reversing 8 kV to -8 kV
[1]
KENNEDY WN, CRICHTON CC, CILLIES DA, et al.Recommended dielectric tests and test procedures for converter transformers and smoothing reactors[J]. , 1986, 1(3): 161-166.
[2]
OKUBOH, SAITOH, KOJIMAH, et al.Discharge mechanism at HVDC polarity reversal in oil/pressboard composite insulation system[C]∥2011 IEEE International Conference on Dielectric Liquids (ICDL). Epirob, , 2011.
[3]
TAKAHASHIE, TSUTSUMIY, OKUYAMAK, et al.Partial discharge characteristics of oil-immersed insulation systems under DC, combined AC-DC and DC reversed polarity voltage[J]. , 1976, 95(1): 411-420.
[4]
CIGRE Working GroupA2/B4.28. HVDC converter transformers design review, test procedures, ageing evaluation and reliability in service[R]. Paris, , 2010.
[5]
OHSHIMAI, MOTEGIS, HONDAM, et al.HVDC breakdown of transformer oil and the effect of space charge on it[J]. , 1983, 102(7): 2208-2215.
[6]
李文平. 特高压换流变压器空间电荷分布的计算分析[J].,2011,48(5):6-10.LIWenping.Calculation and analysis of space-charge distribution of EHV converter transformer[J]. , 2011, 48(5): 6-10.
[7]
李琳,纪锋,李文平,等. 换流变压器极性反转试验的数值模拟[J]. ,2011,30(18):107-112.LILing, JIFeng, LIWenping, et al.Numerical simulation of converter transformer’s polarity reversal test[J]. , 2011, 30(18): 107-112.
[8]
金福宝,周远翔,李光范,等. 交直流复合电场中直流电压分量对油纸绝缘沿面放电过程的影响[J]. ,2015,41(9):3082-3090.JINFubao, ZHOUYuanxiang, LIGuangfan, et al.Effect of DC component characteristics of surface discharge process in oil-paper insulation under combined AC-DC voltage[J]. , 2015, 41(9): 3082-3090.
[9]
吕晓德,陈世坤,方治强,等. 换流变压器端部极性反转电场的数值算法及其绝缘设计[J]. ,1997,31(11):10-14,20.LÜXiaode, CHENShikun, FANGZhiqiang, et al.Numerical computation of polarity reversal electric field in the converter transformer ending and its insulation design[J]. , 1997, 31(11): 10-14, 20.
[10]
王永红,魏新劳,陈庆国. 极性反转电压下油纸复合绝缘的特性[J]. ,2012,32(19):161-168,200.WANGYonghong, WEIXinlao, CHENQingguo.Characteristics of oil-pressboard insulation under polarity reversal voltage[J]. , 2012, 32(19): 161-168, 200.
[11]
WENK, ZHOUY, FUJ, et al.A calculation method and some features of transient field under polarity reversal voltage in HVDC insulation[J]. ,1993, 8(1): 223-230.
[12]
MCDERMIDW, GLODJOA, BROMLEY JC.Analysis of winding failures in HVDC converter transformers[C]∥1999 Proceedings on Electrical Insulation Conference and Electrical Manufacturing & Coil Winding Conference. [S.l.]: , 1999.
[13]
LIUR, TOMKVISTC.Charge storage and transport in oil-impregnated pressboard at polarity reversal under HVDC[C]∥1995 Annual Report, Conference on Electrical Insulation and Dielectric Phenomena. Vasteras, , 1995.
[14]
OKUBOH, SHIMIZUR, SAWADAA, et al.Kerr electro-optic field measurement and charge dynamics in transformer oil/solid composite insulation systems[J]. , 1997, 4(1): 64-70.
[15]
TANGC, CHENG, FUM, et al.Space charge behavior in multi-layer oil-paper insulation under different DC voltages and temperatures[J]. , 2010, 17(3): 775-784.
[16]
MORSHUISP, JEROENSEM.Space charge measurements on impregnated paper: a review of the PEA method and a discussion of results[J]. , 1997, 13(3): 26-35.
[17]
陈义龙. 交直流复合电场下界面电荷对油纸绝缘沿面放电的影响[D]. ,2014.CHENYilong.Effect of interface charge on surface discharge on the oil-impregnated pressboard under combined AC-DC electric field[D]. Beijing, , 2014.
[18]
陈庆国,高源,池明赫,等. 直流电场下典型油纸绝缘结构油流带电特性[J]. ,2014,40(4):995-1001.CHENQinguo, GAOYuan, CHIMinghe, et al.Flow electrification characteristics of typical oil-pressboard insulation under DC electric field[J]. , 2014, 40(4): 995-1001.
[19]
齐波,陈义龙,李成榕,等. 交直流复合非均匀电场下油纸绝缘界面电荷的特性[J]. ,2013,33(34):241-249.QIBo, CHENYilong, LIChengrong, et al.Characteristics of surface charge on oil-impregnated pressboard under non-uniform AC-DC combined electric field[J]. , 2013, 33(34): 241-249.
[20]
Convertor transformers-part 2: transformers for HVDC applications: IEC 61378-2—2001. transformers-part 2: transformers for HVDC applications: IEC 61378-2—2001., 2001.
[21]
王海军. 云广特高压直流输电工程直流保护功能分析及典型故障研究[D]. ,2012.WANGHaijun.Study on DC protection functions and typical fault of Yun-Guang UHVDC project[D]. Guangzhou, , 2012.
[22]
吴昊. 换流变压器油纸绝缘结构油中电场测量及界面电荷特性研究[D]. ,2013.WUHao.Research on measurement of electric field in the oil and interface charge characteristics of converter transformer oil-paper insulation[D]. Beijing, , 2013.
[23]
吴昊,李成榕,齐波,等. 直流电压下油、纸绝缘结构不连续界面空间电荷积聚特性[J]. ,2013,39(6):1419-1425.WUHao, LIChengrong, QIBo, et al.Accumulation characteristics of interface charge in the oil-paper insulation under DC voltage[J]. , 2013, 39(6): 1419-1425.