配电网电磁式电压互感器饱和引起的过电压及过电流的计算分析与抑制措施研究
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摘要
在中性点不接地的配电网中，经常会发生由电磁式电压互感器(PT，potential transformers或TV)饱和引起的铁磁谐振与超低频振荡现象，这将危及系统电气设备的安全运行。
本文利用EMTP程序，对10kV系统电压互感器饱和引起的电磁暂态过程进行了系统的仿真。仿真计算结果表明：当系统线路较短(线路等值对地电容较小)时，系统带母线合闸或线路发生单相接地并自动消失时，会激发起基频谐振或分频谐振，引起系统过电压与PT过电流；当系统线路较长(线路等值对地电容较大)时，系统在单相接地自动消失时，其产生的暂态冲击会在PT和三相线路对地电容回路中，引发超低频振荡，这会在PT中产生极大的过电流。本文给出了系统参数与过电压和过电流的关系曲线，以及典型的过电压与过电流波形。
本文通过仿真计算，讨论了抑制PT引起的过电压与过电流的各种措施，提出了一种能有效抑制过电压与过电流的新型措施，解决了PT饱和引起铁磁谐振过电压和超低频振荡过电流问题，能确保系统安全、可靠运行。
本文还介绍了高压原型模拟试验(10kV)，试验结果与仿真计算基本吻合，验证了仿真计算的正确性。
Ferromagnetic resonance and very low frequencies oscillations caused by saturated Electromagnetic Voltage Transformers often occur in the system neutral point isolated. They can endanger the voltage stability and safety of electric equipments. In this paper, a systemic simulation using Electro-magnetic Transient Program (EMTP) is presented. It is a simulation about electromagnetic transient caused by saturated electromagnetic voltage transformers in 10 kV isolated neutral system. The conclusion is that: if the transmission lines or cables are short (the equivalent capacitance to ground is correspondingly small), single-phase ground fault caused by an intermittent arc or there-phase closing will excite power frequency resonance or subharmonic ferroresonance, then it bring ferromagnetic resonance overvoltage and overcurrent passing through electromagnetic voltage transformers; contrariwise the transmission lines or cables are long (the equivalent capacitance to ground is correspondingly large), single-phase gr
ound fault caused by an intermittent arc will lead the transient shock, which fault shall engender very low frequencies oscillations in the circuit composed by electromagnetic voltage transformers and capacitance to ground of there-phase transmission lines or cables, that bring very large overcurrent passing through electromagnetic voltage transformers.
This paper presents some correlation curves connected system parameters with overvoltage and overcurrent, and some representative wave forms diagrams about overvoltage and overcurrent.
Through simulation calculation, the paper discussed all kinds of eliminations may be restrain those overvoltage and overcurrent, and presents a new elimination can effectively restrain those overvoltage and overcurrent. The new elimination resolve the problem of ferromagnetic resonance overvoltage and very low frequencies oscillation overcurrent caused by saturated electromagnetic voltage transformers. Then some high voltage prototypes simulation tests (10 kV) is presented in this paper. The results of tests are consistent with the result of simulation.
本文利用EMTP程序，对10kV系统电压互感器饱和引起的电磁暂态过程进行了系统的仿真。仿真计算结果表明：当系统线路较短(线路等值对地电容较小)时，系统带母线合闸或线路发生单相接地并自动消失时，会激发起基频谐振或分频谐振，引起系统过电压与PT过电流；当系统线路较长(线路等值对地电容较大)时，系统在单相接地自动消失时，其产生的暂态冲击会在PT和三相线路对地电容回路中，引发超低频振荡，这会在PT中产生极大的过电流。本文给出了系统参数与过电压和过电流的关系曲线，以及典型的过电压与过电流波形。
本文通过仿真计算，讨论了抑制PT引起的过电压与过电流的各种措施，提出了一种能有效抑制过电压与过电流的新型措施，解决了PT饱和引起铁磁谐振过电压和超低频振荡过电流问题，能确保系统安全、可靠运行。
本文还介绍了高压原型模拟试验(10kV)，试验结果与仿真计算基本吻合，验证了仿真计算的正确性。
Ferromagnetic resonance and very low frequencies oscillations caused by saturated Electromagnetic Voltage Transformers often occur in the system neutral point isolated. They can endanger the voltage stability and safety of electric equipments. In this paper, a systemic simulation using Electro-magnetic Transient Program (EMTP) is presented. It is a simulation about electromagnetic transient caused by saturated electromagnetic voltage transformers in 10 kV isolated neutral system. The conclusion is that: if the transmission lines or cables are short (the equivalent capacitance to ground is correspondingly small), single-phase ground fault caused by an intermittent arc or there-phase closing will excite power frequency resonance or subharmonic ferroresonance, then it bring ferromagnetic resonance overvoltage and overcurrent passing through electromagnetic voltage transformers; contrariwise the transmission lines or cables are long (the equivalent capacitance to ground is correspondingly large), single-phase gr
ound fault caused by an intermittent arc will lead the transient shock, which fault shall engender very low frequencies oscillations in the circuit composed by electromagnetic voltage transformers and capacitance to ground of there-phase transmission lines or cables, that bring very large overcurrent passing through electromagnetic voltage transformers.
This paper presents some correlation curves connected system parameters with overvoltage and overcurrent, and some representative wave forms diagrams about overvoltage and overcurrent.
Through simulation calculation, the paper discussed all kinds of eliminations may be restrain those overvoltage and overcurrent, and presents a new elimination can effectively restrain those overvoltage and overcurrent. The new elimination resolve the problem of ferromagnetic resonance overvoltage and very low frequencies oscillation overcurrent caused by saturated electromagnetic voltage transformers. Then some high voltage prototypes simulation tests (10 kV) is presented in this paper. The results of tests are consistent with the result of simulation.
引文
<1>周泽存．高电压技术[M]．1988，北京：中国电力出版社．272
<2>李谦等．电磁式电压互感器铁磁谐振的数值仿真及分析[J]．广西电力技术，1994，(1)．9
<3>韩芳等．10kV系统电压互感器烧损事故分析[J]．电工技术，2003，(8)．43
<4>温新康．10～35kV中性点不接地系统中防止TP高压熔断器熔断的方法[J]．高压电器，2002，(2)．52
<5>黄金辉．“四TV”方式消除铁磁谐振的机理和异常分析[J]．华东电力，2000，(10)．20
<6>陈化钢等．电力设备异常运行及事故处理[M]．1999，北京：中国水利水电出版社．149，155，156
<7>Tanggawelu, B.; Mukerjee, R.N.; Ariffin, A.E.; Ferresonance Studies in Malaysian Utility's Distribution Network, Power Engineering Society General Meeting, 2003, IEEE, Volume: 2,13-17, 2003 Pages:1216-1219
<8>Mozaffari, S.; Sameti, M..; Soudack, A.C.; Effect of initial conditions on chaotic ferroresonance in power transformers, Generation, Transmission and Distribution, IEE Proceedings, Volume: 144,Issue: 5, Sept. 1997 Pages:456 - 460
<9>王晓云等．电力系统铁磁谐振研究现状分析[J]．电力科学与工程，2002，(4)．49
<10>储百森．配电网铁磁谐振防治经验[J]．电工技术杂志，2003，(3)．82
<11>许志龙等．10kV电网TV铁磁谐振过电压数字仿真及研究[J]．电力自动化设备，2001，(2)．27
<12>方瑜．配电网过电压[M]．1994，北京：水利电力出版社．130
<13>李福寿．中性点非有效接地电网的运行[M]．1993，北京：水利电力出版社．22
<14>李谦等．电磁式电压互感器铁磁谐振消谐措施的研究[J]．广西电力技术，1994，(2)．1
<15>H. W. Dommel著，李永庄等译，电力系统电磁暂态计算理论[M]．1991，北京：水利电力出版社．
<16>马仁明，ATP—EMTP程序的使用与说明——武汉高压研究所科学技术报告，1991
<17>徐勇．电压互感器Ⅴ—Ⅰ特性对谐振影响的物理仿真[J]．高电压技术，1997，(4)．61
<18>谢伟山等．广西玉林供电局配电网系统PT谐振过电压研究[J]．广西电力，2002，(3)．24
<19>陈维贤，电网过电压教程[M]．1996，北京：中国电力出版社．181
<20>陈维贤，配电网络互感器谐振及抑制新方法[J]．高电压技术，1993，(3)．3
<21>鲁铁成等．配电系统PT引起的铁磁谐振及抑制新方法[J]．高电压技术，1998，(3)．13
<22>解广润．电力系统过电压[M]．1985，北京：水利电力出版社．284
<23>周洁莲等．防止电压互感器的铁磁谐振过电压的有效措施[J]．高电压技术，2001，(7)．53
<24>张纬钹，高玉明．电力系统过电压与绝缘配合[M]．1988，北京：清华大学出版社
<25>谢宇风．浅谈10kV配电系统中性点的接地方式[J]．华北电力技术，2000，(11)．39
<26>郭自励．消弧线圈接地系统单相接地选线问题[J]．广东电力，2000，(8)．46
<27>蒋德福．非线性网络，1987，水利电力出版社
<28>施围．电力系统过电压计算，1988，西安交通大学出版社
<29>李福寿．电力系统过电压计算，1988，水利电力出版社
<30>吴维韩．电力系统过电压数值计算，1989，科学出版社
<31>电力科学研究院系统所电磁暂态计算组．电磁暂态计算程序例题集，1990
<32>陈维贤．内部过电压基础[M]．1981，北京：水利电力出版社．154～155
<33>Mozaffari, S.; Henschel, S.; Soudack, A.C.; Chaotic ferroresonance in power transformers Generation, Transmission and Distribution, IEE Proceedings-, Volume: 142, Issue: 3, May 1995 Pages:247-250
<34>Al Zahawi, B.A.T.; Emin, Z; Tong, Y.K;Chaos in ferroresonant wound voltage transformers: effect of core losses and universal circuit behaviour Science, Measurement and Technology, IEE Proceedings-, Volume: 145, Issue: 1, Jan. 1998 Pages:39-43
<35>Emin, Z; Al Zahawi, B.A.T.; Auckland, D.W., Tong, Y.K.;Ferroresonance in electromagnetic voltage transformers: a study based on nonlinear dynamics Generation, Transmission and Distribution, IEE Proceedings-, Volume: 144, Issue: 4, July 1997 Pages:383-387
<36>Emin, Z.; Al Zahawi, B.A.T.; Yu Kwong Tong, Ugur, M.;Quantification of the chaotic behavior of ferroresonant voltage transformer circuits Circuits and Systems Ⅰ: Fundamental Theory and Applications, IEEE Transactions on [see also Circuits and Systems Ⅰ: Regular Papers, IEEE Transactions on], Volume: 48, Issue: 6, June 2001 Pages:757 - 760
<37>Sowa, P; Walczak J; Pasko, M.;Evaluation of the influence of the chaotic ferroresonance in transformer on the power system work conditions Electrotechnical Conference, 1998. MELECON 98., 9th Mediterranean, Volume: 2,18-20 May 1998 Pages:1126 - 1130 vol.2
<2>李谦等．电磁式电压互感器铁磁谐振的数值仿真及分析[J]．广西电力技术，1994，(1)．9
<3>韩芳等．10kV系统电压互感器烧损事故分析[J]．电工技术，2003，(8)．43
<4>温新康．10～35kV中性点不接地系统中防止TP高压熔断器熔断的方法[J]．高压电器，2002，(2)．52
<5>黄金辉．“四TV”方式消除铁磁谐振的机理和异常分析[J]．华东电力，2000，(10)．20
<6>陈化钢等．电力设备异常运行及事故处理[M]．1999，北京：中国水利水电出版社．149，155，156
<7>Tanggawelu, B.; Mukerjee, R.N.; Ariffin, A.E.; Ferresonance Studies in Malaysian Utility's Distribution Network, Power Engineering Society General Meeting, 2003, IEEE, Volume: 2,13-17, 2003 Pages:1216-1219
<8>Mozaffari, S.; Sameti, M..; Soudack, A.C.; Effect of initial conditions on chaotic ferroresonance in power transformers, Generation, Transmission and Distribution, IEE Proceedings, Volume: 144,Issue: 5, Sept. 1997 Pages:456 - 460
<9>王晓云等．电力系统铁磁谐振研究现状分析[J]．电力科学与工程，2002，(4)．49
<10>储百森．配电网铁磁谐振防治经验[J]．电工技术杂志，2003，(3)．82
<11>许志龙等．10kV电网TV铁磁谐振过电压数字仿真及研究[J]．电力自动化设备，2001，(2)．27
<12>方瑜．配电网过电压[M]．1994，北京：水利电力出版社．130
<13>李福寿．中性点非有效接地电网的运行[M]．1993，北京：水利电力出版社．22
<14>李谦等．电磁式电压互感器铁磁谐振消谐措施的研究[J]．广西电力技术，1994，(2)．1
<15>H. W. Dommel著，李永庄等译，电力系统电磁暂态计算理论[M]．1991，北京：水利电力出版社．
<16>马仁明，ATP—EMTP程序的使用与说明——武汉高压研究所科学技术报告，1991
<17>徐勇．电压互感器Ⅴ—Ⅰ特性对谐振影响的物理仿真[J]．高电压技术，1997，(4)．61
<18>谢伟山等．广西玉林供电局配电网系统PT谐振过电压研究[J]．广西电力，2002，(3)．24
<19>陈维贤，电网过电压教程[M]．1996，北京：中国电力出版社．181
<20>陈维贤，配电网络互感器谐振及抑制新方法[J]．高电压技术，1993，(3)．3
<21>鲁铁成等．配电系统PT引起的铁磁谐振及抑制新方法[J]．高电压技术，1998，(3)．13
<22>解广润．电力系统过电压[M]．1985，北京：水利电力出版社．284
<23>周洁莲等．防止电压互感器的铁磁谐振过电压的有效措施[J]．高电压技术，2001，(7)．53
<24>张纬钹，高玉明．电力系统过电压与绝缘配合[M]．1988，北京：清华大学出版社
<25>谢宇风．浅谈10kV配电系统中性点的接地方式[J]．华北电力技术，2000，(11)．39
<26>郭自励．消弧线圈接地系统单相接地选线问题[J]．广东电力，2000，(8)．46
<27>蒋德福．非线性网络，1987，水利电力出版社
<28>施围．电力系统过电压计算，1988，西安交通大学出版社
<29>李福寿．电力系统过电压计算，1988，水利电力出版社
<30>吴维韩．电力系统过电压数值计算，1989，科学出版社
<31>电力科学研究院系统所电磁暂态计算组．电磁暂态计算程序例题集，1990
<32>陈维贤．内部过电压基础[M]．1981，北京：水利电力出版社．154～155
<33>Mozaffari, S.; Henschel, S.; Soudack, A.C.; Chaotic ferroresonance in power transformers Generation, Transmission and Distribution, IEE Proceedings-, Volume: 142, Issue: 3, May 1995 Pages:247-250
<34>Al Zahawi, B.A.T.; Emin, Z; Tong, Y.K;Chaos in ferroresonant wound voltage transformers: effect of core losses and universal circuit behaviour Science, Measurement and Technology, IEE Proceedings-, Volume: 145, Issue: 1, Jan. 1998 Pages:39-43
<35>Emin, Z; Al Zahawi, B.A.T.; Auckland, D.W., Tong, Y.K.;Ferroresonance in electromagnetic voltage transformers: a study based on nonlinear dynamics Generation, Transmission and Distribution, IEE Proceedings-, Volume: 144, Issue: 4, July 1997 Pages:383-387
<36>Emin, Z.; Al Zahawi, B.A.T.; Yu Kwong Tong, Ugur, M.;Quantification of the chaotic behavior of ferroresonant voltage transformer circuits Circuits and Systems Ⅰ: Fundamental Theory and Applications, IEEE Transactions on [see also Circuits and Systems Ⅰ: Regular Papers, IEEE Transactions on], Volume: 48, Issue: 6, June 2001 Pages:757 - 760
<37>Sowa, P; Walczak J; Pasko, M.;Evaluation of the influence of the chaotic ferroresonance in transformer on the power system work conditions Electrotechnical Conference, 1998. MELECON 98., 9th Mediterranean, Volume: 2,18-20 May 1998 Pages:1126 - 1130 vol.2