摘要
近年来,我国加快了直流输电工程的建设。直流输电具有众多优点,同时也不可避免地给电网带来许多问题。其中,直流馈入对交流保护动作特性的影响是值得重点关注的问题之一。在交直流混合系统中,交流与直流系统间存在紧密的电气耦合关系,其相互作用的故障暂态过程必然将改变交流电网继电保护的运行环境而对交流保护的动作行为造成影响,严重时将造成其误动或拒动。目前,相关的研究成果仍不多见,更缺乏系统的理论分析和研究。为此,本文针对多直流馈入下受端交流电网的继电保护动作特性进行了深入的研究,主要研究内容有:
1.在对直流系统换相失败特性深入研究的基础上,对不同受端交流电网故障所引发的直流系统换相失败等暂态过程特点进行了系统的分析。
2.建立了适用于直流受端交流电网故障分析的直流系统等值工频变化量阻抗模型,利用该模型对不同故障情况下直流系统等值工频变化量阻抗特性进行了分析。在此基础上,结合输电线路工频变化量方向保护原理,通过对受端交流电网故障及其诱发的直流系统暂态过程中工频变化量方向元件动作特性的定量分析,揭示了直流馈入对其影响的机理。通过对直流换相失败暂态过程引发非故障线路方向元件感受的暂态功率方向突变问题的研究,并结合方向纵联保护不同的动作逻辑,研究了直流换相失败暂态过程造成非故障线路方向纵联保护误动行为。在上述研究的基础上,对多直流馈入环境下受端电网输电线路工频变化量方向纵联保护动作特性进行了分析研究。基于PSCAD/EMTDC仿真,全面系统地验证了理论分析的正确性。
3.在分析研究了受端交流电网故障及其诱发的直流系统暂态过程中直流系统等值故障分量电流暂态特性的基础上,对直流馈入下受端交流电网输电线路电流差动保护故障分量判据和稳态量判据的动作特性进行了全面系统的理论分析与研究,揭示了直流馈入对电流差动保护影响的机理。在此基础上,对多直流馈入下输电线路电流差动保护动作特性进行了分析研究。基于PSCAD/EMTDC仿真,全面系统地验证了理论分析的正确性。
4.在对受端交流电网故障及其诱发的直流系统暂态过程中直流系统等值工频量电流暂态特性分析研究的基础上,从距离保护测量阻抗变化的角度,对直流馈入下输电线路距离保护的动作特性进行了全面系统的理论分析与研究,揭示了直流馈入对输电线路距离保护影响的机理。在此基础上,对多直流馈入环境下输电线路距离保护动作特性进行了分析研究。基于PSCAD/EMTDC仿真,全面系统地验证了理论分析的正确性。
本文研究工作得到了“十一五”国家科技支撑计划重大项目(2006BAA02A30) ,国家自然科学基金项目(50977032)和粤港关键领域重点突破项目(2009498B3201)的资助。
In recent years, China has accelerated the construction of direct current transmission projects. HVDC system has many advantages, but also inevitably brings many problems to the network. Among them, the impact of the HVDC infeed on the the operation characteristics of the AC protections is one of the issues that should be focused. In the AC-DC interconnected system, there is a close electrical coupling relationship between AC system and HVDC system. The fault transient process of two systems’interaction will change the operation environment of the AC system protections inevitably, so that it will influence the actions of those protections. In the worst situation, it will lead to the malfunctions or rejecting operations of the AC protections. At present, relevant research results are still rare, but the lack of systematic and theoretical analysis and research. Therefore, this paper deep studies the operation characteristics of the receiving AC network’s protections under the situation of multi-infeed HVDC system. The main contents are decribed below:
1. Based on the in-depth study of HVDC commutation failure characteristics, transient process of commutation failures caused by the different receiving AC network faults is analyzed systematically.
2. The impedance model of HVDC equivalent power-frequency component variation is eatablished to analyze the AC-DC interconnected system faults. On this basis, considering the principle of power-frequency componet variation direction relay, the impacts of commutation failure on power-frequency component variation elements of the fault line are analyzed. And the factors leading to the rejecting operation of power-frequency component variation directional pilot protection are also analyzed quantitatively in different situations. The issue of the transient power direction sudden change of the non-fault line direction element caused by the commutation failure transient process is analyzed. And then, based on the different action logic of direction pilot protection, the malfunction operation of directional pilot proctection of the non-fault line caused by the commutation failure transient process is analyzed. Then the action characteristics of the directional pilot protection under the situation of multi-infeed HVDC system are analyzed. The validity of theoretical analysis is proved based on the PSCAD/EMTDC simulation at last.
3. Based on the theoretical analysis of fault component criterion and steady state component criterion of transmission line current differential protection, considering the transient characteristics of HVDC equivalent fault current component under the different AC fault situations, the influence mechanisms of the infeed HVDC on the fault component criterion and steady state component criterion of transmission line current differential protection are analyzed comprehensively. The HVDC impacts on the fault component criterion and steady state component criterion of transmission line current differential protection are theoretically analyzed and compared in different operation situations.Then the action characteristics of transmission line current differential protection under the situation of multi-infeed HVDC system are analyzed. At last, the validity of theoretical analysis is proved based on the PSCAD/EMTDC simulation.
4. Considering the characteristics of distance protection, the impacts of infeed HVDC system on the transmission line distance protection are analyzed from the point of measured impedance variation angle of distance protection caused by the infeed HVDC system. Based on the faults of receiving network and commutation failures caused by the faults of receiving network, the impacts of HVDC system on the transmission line distance protection are theoretically analyzed and compared under the different operation situations of receiving network. Then the action characteristics of distance protection are analyzed under the situation of multi-infeed HVDC system. At last, the validity of theoretical analysis is proved based on the PSCAD/EMTDC simulation.
This dissertation is supported by Key Project of the National Eleventh-Five Year Research Program of China (2006BAA02A30) ,National Natural Science Foundation of China(50977032) and Guangdong-Hongkong Technology Cooperation Funding (2009498B3201) .
引文
[1]浙江大学发电教研组直流输电科研组.直流输电[M].杭州:浙江大学出版社.
[2]赵畹君.高压直流输电工程技术[M].北京:中国电力出版社,2004.
[3]李兴源.高压直流输电系统的运行和控制[M].北京:科学技术出版社, 1998.
[4]杨汾艳,徐政.直流输电系统典型暂态响应特性分析[J].电工技术学报,2005,20(3):45-52.
[5]马玉龙,肖湘宁,姜旭,等. HVDC换流器的阻抗频率特性[J].电力系统自动化, 2006, 30(12): 66~69.
[6] J. Arrillaga. High Voltage Direct Current Transmission[M]. London: Institution of Electrical Engineers, 1998.
[7] Vassilios G.Agelidis, Georgios D.Demetriades, Nikolas Flourentzou. Recent Advances in High-Voltage Direct-Current Power Transmission Systems[C].中国电工技术学会电力电子学会第十届学术年会. 2006:1-9.
[8] K. R. Padiyar. HVDC power transmission systems: technology and system interactions[C]. New Age International, 1990.
[9]汪秀丽.特高压输电技术的发展[J].水利电力科技,2006,32(2):6-16.
[10]周孝信.我国电网技术的现状与未来[J].电网技术,1995,19(2):1-4.
[11] Hammons, T.J., Woodford, et al. Role of HVDC transmission in future energy development[J]. Power Engineering Review, IEEE. 2000, 20(2):10-25.
[12]张文亮,于永清,李光范,范建斌,宿志一,陆家榆,李博.特高压直流技术研究[J].中国电机工程学报. 2007, 27(22):1-6.
[13]刘振亚.特高压电网[M].中国经济出版社,2005.
[14]张文亮,胡毅.发展特高压交流输电,促进全国联网[J].高电压技术, 2003, 29(8): 20-21, 31.
[15]张文亮,吴维宁,胡毅.特高压输电技术的研究与我国电网的发展[J].高电压技术,2003,29(9):16-18.
[16]张文亮,胡毅.特高压输变电设备应用于工程的分析研究[J].电力设备,2004,5(7):15-18.
[17]李峰,管霖,钟杰峰,等.广东交直流混合电网的运行稳定性研究[J].电网技术. 2005, 29(11):1-4.
[18]常浩.我国高压直流输电工程国产化回顾及现状[J].高电压技术. 2004, 30(11):3,4,36.
[19] De Toledo, P.F., Jiuping Pan ,Srivastava, K., et al. Case Study of a Multi-Infeed HVDC System[C]. Power System Technology and IEEE Power India Conference, 2008: 1-7.
[20]毛晓明,管霖,张尧,等.超高压大功率直流输电系统的先进控制技术应用及发展[J].电力自动化设备,2004,24(9):91-95.
[21]刘之尧,唐卓尧,张文峰等.直流换相失败引起继电保护误动分析[J].电力系统自动化,2006,30(19): 104-107.
[22]鲁德锋,毛为民,冼伟雄.直流换流站换流失败引起继电保护不正确动作的分析及防范措施探讨[J].电力设备,2006,7(1): 54-56.
[23]邵震,王炳炎.直流输电换相失败对交流侧继电保护的影响[J].高电压技术, 2006,32(9):42-45.
[24]周长春,徐政.直流输电准稳态模型有效性的仿真验证[J].中国电机工程学报, 2003,23(12):33-36.
[25]倪以信,陈寿孙,张宝霖.动态电力系统的理论和分析[M].北京:清华大学出版社.
[26]戚庆茹.动态相量理论在现代电力系统仿真中的应用[D].北京:清华大学, 2004.
[27]杨秀,陈陈.基于采样数据模型的高压直流输电动态特性分析[J].中国电机工程学报, 2005, 25( 10): 7-11, 136.
[28]杨秀,陈陈.高压直流输电的采样数据动态建模[J].中国电机工程学报, 2004, 24(7): 30-34.
[29]孙栩,孔力. VSC-HVDC系统的动态相量法建模仿真分析[J].电力系统自动化, 2008,1(32): 44-47.
[30] ZHU Hao-jun, CAI Ze-xiang, LIU Hao-ming, et al. Hybrid model transient stability simulation using dynamic phasors based HVDC system model [J]. Electric Power System Research, 2006, 76(6): 582-591.
[31]戚庆茹,焦连伟,严正,等.高压直流输电动态相量建模与仿真[J].中国电机工程学报, 2003, 23(12): 28-32.
[32] ARRILLAGA J, CALLAGHAN C D. Three-phase AC-DC load and harmonic flows [J]. IEEE Trans. on Power Delivery, 1991, 6(1): 238-244.
[33] CALLAGHAN C D, ARRILLAGA J. Double iterative algorithm for the analysis ofpower and harmonic flows at AC-DC converter terminals [J]. IEE Proc. Pt. C, Gener . Transm. Distrib., 1989, 136(6): 319– 324.
[34] YACAMINI R, de OLIVEIRA J C. Harmonics in multiple converter systems: a generalized approach [J]. IEE Proc. Electr. Power Appl., 1980, 127(2):96-106.
[35]夏道止,沈赞埙.高压直流输电系统的谐波分析及滤波[M].北京:水利电力出版社, 1994.
[36] SMITH B C, WATSON N R, WOOD A R, et al. A newton solution for the harmonic phasor analysis of AC-DC converters [J]. IEEE Trans. on Power Delivery,1996, 11(2): 965-971.
[37] SMITH B C, WATSON N R, WOOD A R, et al. Steady state model of the AC / DC converter in the harmonic domain[J]. IEE Proc. Gener . Transm., 1995, 142(2):109-118.
[38] HU L, RAN L. Direct method for calculation of AC side harmonics and interharmonics in a HVDC system [J]. IEE Proc. Gener. Transm. Distrib., 2000, 147(6): 329-335.
[39] HU L, MORRISON R E. AC side equivalent circuit based method for harmonic analysis of a converter system [J]. IEE Proc. Electr. Power Appl., 1999, 146(1): 103-110.
[40]马玉龙,肖湘宁,姜旭.交流系统接地故障对HVDC的影响分析[J].中国电机工程学报, 2006,11(26):144-149.
[41] WOOD A R, ARRILLAGA J. HVDC converter waveform distortion: a frequency-domain analysis [J]. IEE Proc. Gener. Transm. Distrib., 1995, 142(1): 88-96.
[42] WOOD A R, ARRILLAGA J. The frequency dependent impedance of an HVDC converter [J]. IEEE Trans. on Power Delivery, 1995, 10(3): 1635-1641.
[43] HU L, YACAMINI R. Calculation of harmonics and interharmonics in HVDC schemes with low DC side impedance[J]. IEE Proc. C. Gener. Transm. Distrib., 1993, 140(6): 469-476.
[44] Hu L, Morrison R E. The use of modulation theory to calculate the harmonic distortion in HVDC systems operating on an unbalanced supply [J]. IEEE Trans. on Power Systems, 1997, 12(2): 973-980.
[45] HU L, YACAMINI R. Calculation of harmonic interference in HVDC systems with unbalance [C]. Proceedings of IEE Fourth International Conference on AC and DC Power Transmission. 1991:390-394.
[46] Taizo H, Joukichi M, Oue Y. Screening for HVDC system core saturation instability [J].IEEE Trans on Power Delivery, 2000,15(4):1291-1297.
[47] Hammad A E. Analysis of Second Harmonic Instability for the Chateauguay HVDC/SVC scheme [J]. IEEE Transactionson Power Delivery, 1992, 7(l):410-415.
[48] JiangX,Gole A M. A Frequency Scanning Method for the Identification of Harmonic Instabilities in HVDC Systems[J]. IEEE Transactionson Power Delivery, 1995, 10(4):1875-1881.
[49] Peter R. Harmonic Voltage and Current Transfer, and AC- and DC-Side Impedances of HVDC Converters [J]. IEEE Transactions On Power Delivery, 2005, 20(3): 2095-2099.
[50]戴熙杰.直流输电基础[M].北京:水利电力出版社,1999.
[51]杨卫东,徐政,韩祯祥.多馈入交直流电力系统研究中的相关问题[J].电网技术, 2000, 24(8): 13-17.
[52]郝跃东,倪汝冰. HVDC换相失败影响因素分析[J].高电压技术, 2006,32(9):38-43.
[53]荆勇,欧开健,任震.交流单相故障对高压直流输电换相失败的影响[J].高电压技术, 2004, 3(30):60-62.
[54] Tian H K,Sng E K K.A novel solution to restore a three-phase thyristor inverter from commutation failure due to voltage dip[C].Proceedings of 35th Power Electronics Specialists Conference,Aachen,2004,2:906-912.
[55] Zhou Changchun,Xu Zheng.Study on commutation failure of multi-infeed HVDC system[C].Proceedings of International Conference on Power System Technology,2002,4:2462-2466.
[56]杨卫东,徐政,韩祯祥.NETOMAC在直流输电系统仿真研究中的应用[J].电力自动化设备,2001,21(4):10-14.
[57]何朝荣,李兴源.影响多馈入高压直流换相失败的耦合导纳研究[J].中国电机工程学报,2008,28(7):51-57.
[58]陈红军.高压直流输电系统故障及控制策略[J].华中电力,2001,14(5):5-8.
[59]吴红斌,丁明,刘波.交直流系统暂态仿真中换流器的换相过程分析[J].电网技术,2004,28(17):11-14.
[60] C. V. Thio, J. B. Davies, and K. L. Kent. Commutation failures in HVDC transmission systems [J]. IEEE Trans. Power Delivery. 1996, 11(2): 946-957.
[61] Lai L L,Ndeh-Che F,Chari T,et al.HVDC system fault diagnosis with neural networks[C].Proceedings of the 5th European Conference on Power Electronics andApplications,Brighton,1993,18:145-150.
[62] Lai L L,Ndeh-Che F,Tejedo C.Fault identification in HVDC systems with neural networks[C].Proceedings of IEE APSCOM-93,Hong Kong,1993,1:231-236.
[63] Bawane N,Kothari A G.Artificial neural network based fault identification of HVDC converter[C].Proceedings of 2003 IEEE International Symposium on Diagnostics for Electrical Machines Power Electronics and Drives,Atlanta,2003:152-157.
[64] Sato M,Yamaji K,Sekita M,et al.Development of a hybrid margin angle controller for HVDC continuous operation[J].IEEE Trans on Power Systems,1996,11(4):1792-1798.
[65]邵震霞,李兴源.高压直流输电系统控制器数字仿真实现方法[J].四川大学学报(工程科学版),2002,34(3):80-83.
[66] Arne Hansen, Henrik Havemann. Decreasing the commutation failure frequency in HVDC transmission systems[J]. IEEE Trans. Power Delivery. 2000, 15(3):1022-1026.
[67]吴晔,殷威扬.逆变侧熄弧角Gamma-Kick控制仿真计算[J].高电压技术,2005,31(2):31-32.
[68]江道灼.直流输电系统换相电压峰值检测方法[J].华东电力,1995,(8):1-4.
[69] Hansen A,Havemann H.Decreasing the commutation failure frequency in HVDC transmission systems[J].IEEE Trans on Power Delivery,2000,15(3):1022-1026.
[70] Tamai S,Naitoh H,Ishiguro F,et al.Fast and predictive HVDC extinction angle control[J].IEEE Trans on Power Systems,1997,12(3):1268-1275.
[71] Zhang Lidong,Dofnas L.A novel method to mitigate commutation failures in HVDC systems[C].Proceedings of International Conference on Power System Technology,Kunming,2002,1:51-56.
[72]陈树勇,李新年,余军,等.基于正余弦分量检测的高压直流换相失败预防方法[J].中国电机工程学报,2005,25(14):1-6.
[73] Ottosson N,Kjellin L.Modular back-to-back HVDC with capacitor commutated converters(CCC)[C].Proceedings of the 7th International Conference on AC-DC Power Transmission,London,2001:55-59.
[74] Rezek A J J,dos Santos Izidoro AA,Souza de Sa J,et al.The capacitor commutated converter(CCC)as an alternative for application in HVDC projects[C].Proceedings ofIEEE International Symposium on Industrial Electronics,Rio De Janeiro,2003,1:432-437.
[75] Tsubota S,Funaki T,Matsuura K.Analysis of interconnection between HVDCtransmission with capacitor commutated converter and AC power transmission system[C].Proceedings of IEEE Power Engineering Society Winter Meeting,Singapore,2000,4:2926-2931.
[76] Tanaka T,Nakazato M,Funabiki S.A new approach to the capacitor-commutated converter for HVDC-a combined commutation-capacitor of active and passive capacitors[C].Proceedings of IEEE Power Engineering Society Winter Meeting,Columbus,2001,2:968-973.
[77]欧开健,任震,荆勇.直流输电系统换相失败的研究(二)——避免换相失败的措施[J].电力自动化设备, 2003, 6(23):5-8.
[78]周长春,徐政.联于弱交流系统的HVDC故障恢复特性仿真分析[J].电网技术, 2003, 27(11): 18-21.
[79]周波.直流输电系统控制和运行[D].北京:华北电力大学, 1998.
[80]刘炳君,李世作.高压交直流混合输电系统换相失败的研究[J].电器开关. 2010,(1):27-30.
[81] Kristmundesson G M,Carroll D P.The effect of AC system frequency spectrum on commutation failure in HVDC inverters[J].IEEE Trans on Power Delivery,1990,5(2):1121-1128.
[82] F. Andersson, L.E. Juhlin, T. Jones. AC line protection operating conditions in the near vicinity of HVDC installations[C]. Proceedings of Fifth International Conference on Developments in Power System Protection, 1993: 119-122.
[83]刘强,蔡泽祥,刘为雄,等.交直流互联电网暂态功率倒向及对继电保护的影响[J].电力系统自动化. 2007,31(7):34-38.
[84]贺家李,宋从矩.电力系统继电保护原理(增订版)[M].北京:中国电力出版社,2004.
[85]沈国荣.工频变化量方向继电器研究[J].电力系统自动化,1983, 30(1):1-10.
[86]朱声石.高压电网继电保护原理与技术[M].北京:中国电力出版社, 2005.
[87]徐政.交直流电力系统动态行为分析[M].北京:机械工业出版社, 2004.
[88]陈久林,陈建民,张量,等.功率倒向对平行双回线纵联保护的影响分析及对策[J].电力系统自动化. 2006,30(2):105-108.