基于序网等值电路的双馈风电机组接入系统短路电流计算方法
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摘要
为了方便和准确地计算双馈风电机组(DFIG)接入系统的短路电流分布,提出了投撬棒后DFIG的工频和转频序网等值电路,并给出了利用该等值电路计算系统短路电流的方法。通过求解投撬棒后DFIG磁链的状态微分方程,得到其工频分量和转频分量的解析表达式。在此基础上,将DFIG的电压空间矢量方程按转频和工频分量进行分解,并根据空间矢量与相量间的关系,分别形成了转频和工频序网等值电路。其中,转频正序、负序等值电路分别为带内阻抗的电势和无源阻抗,而工频正序、负序等值电路均为无源阻抗。利用该等值电路只需已知DFIG的电机参数和故障初值条件而无需仿真即可求得DFIG接入系统各处的短路电流。以某DFIG接入系统为例,通过PSCAD仿真验证了该等值电路和短路计算方法在不同故障条件下的有效性。
To calculate the short circuit current distribution in power system integrated with DFIG(DoublyFed Induction Generator) conveniently and accurately,the rotor speed frequency and power frequency equivalent sequence circuits of DFIG with Crowbar protection are proposed,based on which,a short circuit current calculation method of the system is given. The analytic expressions of power frequency component and rotor speed frequency component of DFIG flux linkage are obtained by solving the state differential equation of DFIG flux linkage with Crowbar protection. Based on this,the space vector equation of DFIG voltage is decomposed into rotor speed frequency and power frequency components,to obtain the equivalent sequence circuits for rotor speed frequency and power frequency respectively according to the relationship between space vector and phasor. The negative and positive sequence equivalent circuits of rotor speed frequency are passive impedance and electric potential with internal impedance respectively and the negative and positive sequence equivalent circuits of power frequency are both passive impedance. Based on the equivalent circuits the short circuit currents in power system integrated with DFIG can be calculated with only DFIG electric machine parameters and initial conditions of failure without simulation. The system integrated with DFIG is simulated in PSCAD to verify the effectiveness of the equivalent circuits and short circuit current calculation method with different faults in the system.
To calculate the short circuit current distribution in power system integrated with DFIG(DoublyFed Induction Generator) conveniently and accurately,the rotor speed frequency and power frequency equivalent sequence circuits of DFIG with Crowbar protection are proposed,based on which,a short circuit current calculation method of the system is given. The analytic expressions of power frequency component and rotor speed frequency component of DFIG flux linkage are obtained by solving the state differential equation of DFIG flux linkage with Crowbar protection. Based on this,the space vector equation of DFIG voltage is decomposed into rotor speed frequency and power frequency components,to obtain the equivalent sequence circuits for rotor speed frequency and power frequency respectively according to the relationship between space vector and phasor. The negative and positive sequence equivalent circuits of rotor speed frequency are passive impedance and electric potential with internal impedance respectively and the negative and positive sequence equivalent circuits of power frequency are both passive impedance. Based on the equivalent circuits the short circuit currents in power system integrated with DFIG can be calculated with only DFIG electric machine parameters and initial conditions of failure without simulation. The system integrated with DFIG is simulated in PSCAD to verify the effectiveness of the equivalent circuits and short circuit current calculation method with different faults in the system.
引文
[1]苏常胜,李凤婷,武宇平.双馈风电机组短路特性及对保护整定的影响[J].电力系统自动化,2011,35(6):86-91.SU Changsheng,LI Fengting,WU Yuping.An analysis on shortcircuit characteristic of wind turbine driven doubly fed induction generator and its impact on relay setting[J].Automation of Electric Power Systems,2011,35(6):86-91.
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[9]SULLA F,SVENSSON J,SAMUELSSON O.Symmetrical and unsymmetrical short-circuit current of squirrel-cage and doubly-fed induction generators[J].Electric Power Systems Research,2011,81:1610-1618.
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[11]黄涛,陆于平,凌启程,等.撬棒电路对风电场侧联络线距离保护的影响及对策[J].电力系统自动化,2013,37(17):30-36.HUANG Tao,LU Yuping,LING Qicheng,et al.Impact of crowbar on wind farm side interconnection line distance protection and mitigation method[J].Automation of Electric Power Systems,2013,37(17):30-36.
[12]沈枢,张沛超,方陈,等.双馈风电场故障序阻抗特征及对选相元件的影响[J].电力系统自动化,2014,38(15):87-92.SHEN Shu,ZHANG Peichao,FANG Chen,et al.Characteristics of sequence impedance of DFIG plant and influence on phase selector[J].Automation of Electric Power Systems,2014,38(15):87-92.
[13]张保会,张金华,原博,等.风电接入对继电保护的影响(六)---风电场送出线路距离保护影响分析[J].电力自动化设备,2013,33(6):1-6.ZHANG Baohui,ZHANG Jinhua,YUAN Bo,et al.Impact of wind farm integration on relay protection(6):analysis of distance protection for wind farm outgoing transmission line[J].Electric Power Automation Equipment,2013,33(6):1-6.
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[15]孔祥平,张哲,尹项根,等.计及撬棒保护影响的双馈风力发电机组故障电流特性研究[J].电工技术学报,2015,30(8):1-10.KONG Xiangping,ZHANG Zhe,YIN Xianggen,et al.Study of fault current characteristics of DFIG considering impact of crowbar protection[J].Transactions of China Electrotechnical Society,2015,30(8):1-10.
[16]欧阳金鑫,王利平,熊小伏,等.双馈风电机组多机并联运行的短路电流特征及其机理[J].电力系统自动化,2016,40(3):74-80.OUYANG Jinxin,WANG Liping,XIONG Xiaofu,et al.Characteristics and mechanism of short-circuit currents contributed by doubly-fed wind turbines under parallel operation[J].Automation of Electric Power Systems,2016,40(3):74-80.
[17]周念成,罗艾青,王强钢,等.含多感应发电机的配电网短路计算对称分量法[J].电力系统自动化,2013,37(11):65-70.ZHOU Niancheng,LUO Aiqing,WANG Qianggang,et al.Symmetrical components method for short-circuit current calculation of induction generator in distribution network[J].Automation of Electric Power Systems,2013,37(11):65-70.
[18]王燕萍,郑涛,王增平,等.不同转差率对双馈风机撬棒投入后的短路电流影响分析[J].电力系统保护与控制,2015,43(17):8-14.WANG Yanping,ZHENG Tao,WANG Zengping,et al.Impact analysis of different slips on the short circuit current of DFIGafter crowbar operation[J].Power System Protection and Control,2015,43(17):8-14.
[2]童宁,林湘宁,李正天,等.对称电压跌落条件下双馈风电机群馈出电流与线路电流保护的交互影响[J].中国电机工程学报,2014,34(22):3806-3814.TONG Ning,LIN Xiangning,LI Zhengtian,et al.Study for reciprocal effect between overcurrent protection and doubly-fed induction generator feeding current under the condition of symmetrical voltage sag[J].Proceedings of the CSEE,2014,34(22):3806-3814.
[3]陈琳浩,张金华,都劲松,等.采用电压极化的比相式距离保护用于双馈式风电场送出线路适用性分析[J].电力自动化设备,2016,36(9):74-79.CHEN Linhao,ZHANG Jinhua,DU Jinsong,et al.Applicability of phase-comparison distance protection based on polarized voltage for outgoing transmission line of DFIG-based wind farm[J].Electric Power Automation Equipment,2016,36(9):74-79.
[4]武晗,孙建龙,乔黎伟,等.考虑LVRT的风电场馈线短路电流特性与保护整定计算[J].电网技术,2016,40(10):3019-3028.WU Han,SUN Jianlong,QIAO Liwei,et al.Short circuit current characteristics and calculation of current protection setting of feeder lines in wind farms considering LVRT[J].Power System Technology,2016,40(10):3019-3028.
[5]张保会,李光辉,王进,等.风电接入电力系统故障电流的影响因素分析及对继电保护的影响[J].电力自动化设备,2012,32(2):1-8.ZHANG Baohui,LI Guanghui,WANG Jin,et al.Affecting factors of grid-connected wind power on fault current and impact on protection relay[J].Electric Power Automation Equipment,2012,32(2):1-8.
[6]MORREN J,HANA S W H D.Short-circuit current of wind turbines with doubly fed induction generator[J].IEEE Transactions on Energy Conversion,2007,22(1):174-180.
[7]李辉,赵猛,叶仁杰,等.电网故障下双馈风电机组暂态电流评估及分析[J].电机与控制学报,2010,14(8):45-51.LI Hui,ZHAO Meng,YE Renjie,et al.Evaluation and analysis of transient current of a DFIG wind generation system under grid fault[J].Electric Machines and Control,2010,14(8):45-51.
[8]PANNELL G,ATKINSON D J,ZZHAWI B.Analytical study of grid-fault response of wind turbine doubly fed induction generator[J].IEEE Transactions on Energy Conversion,2010,25(4):1081-1091.
[9]SULLA F,SVENSSON J,SAMUELSSON O.Symmetrical and unsymmetrical short-circuit current of squirrel-cage and doubly-fed induction generators[J].Electric Power Systems Research,2011,81:1610-1618.
[10]郑涛,魏占朋,迟永宁,等.考虑撬棒保护动作时间的双馈式风电机组短路电流特性[J].电力系统自动化,2014,38(5):25-30.ZHENG Tao,WEI Zhanpeng,CHI Yongning,et al.Short-circuit current characteristic of doubly fed induction generator considering crowbar protection insertion time[J].Automation of Electric Power Systems,2014,38(5):25-30.
[11]黄涛,陆于平,凌启程,等.撬棒电路对风电场侧联络线距离保护的影响及对策[J].电力系统自动化,2013,37(17):30-36.HUANG Tao,LU Yuping,LING Qicheng,et al.Impact of crowbar on wind farm side interconnection line distance protection and mitigation method[J].Automation of Electric Power Systems,2013,37(17):30-36.
[12]沈枢,张沛超,方陈,等.双馈风电场故障序阻抗特征及对选相元件的影响[J].电力系统自动化,2014,38(15):87-92.SHEN Shu,ZHANG Peichao,FANG Chen,et al.Characteristics of sequence impedance of DFIG plant and influence on phase selector[J].Automation of Electric Power Systems,2014,38(15):87-92.
[13]张保会,张金华,原博,等.风电接入对继电保护的影响(六)---风电场送出线路距离保护影响分析[J].电力自动化设备,2013,33(6):1-6.ZHANG Baohui,ZHANG Jinhua,YUAN Bo,et al.Impact of wind farm integration on relay protection(6):analysis of distance protection for wind farm outgoing transmission line[J].Electric Power Automation Equipment,2013,33(6):1-6.
[14]黄涛,陆于平.投撬棒后双馈风机暂态电势的变化特性分析[J].电网技术,2014,38(10):2759-2765.HUANG Tao,LU Yuping.Analysis on transient EMF variation characteristic of doubly fed induction generator after crowbar protection activated[J].Power System Technology,2014,38(10):2759-2765.
[15]孔祥平,张哲,尹项根,等.计及撬棒保护影响的双馈风力发电机组故障电流特性研究[J].电工技术学报,2015,30(8):1-10.KONG Xiangping,ZHANG Zhe,YIN Xianggen,et al.Study of fault current characteristics of DFIG considering impact of crowbar protection[J].Transactions of China Electrotechnical Society,2015,30(8):1-10.
[16]欧阳金鑫,王利平,熊小伏,等.双馈风电机组多机并联运行的短路电流特征及其机理[J].电力系统自动化,2016,40(3):74-80.OUYANG Jinxin,WANG Liping,XIONG Xiaofu,et al.Characteristics and mechanism of short-circuit currents contributed by doubly-fed wind turbines under parallel operation[J].Automation of Electric Power Systems,2016,40(3):74-80.
[17]周念成,罗艾青,王强钢,等.含多感应发电机的配电网短路计算对称分量法[J].电力系统自动化,2013,37(11):65-70.ZHOU Niancheng,LUO Aiqing,WANG Qianggang,et al.Symmetrical components method for short-circuit current calculation of induction generator in distribution network[J].Automation of Electric Power Systems,2013,37(11):65-70.
[18]王燕萍,郑涛,王增平,等.不同转差率对双馈风机撬棒投入后的短路电流影响分析[J].电力系统保护与控制,2015,43(17):8-14.WANG Yanping,ZHENG Tao,WANG Zengping,et al.Impact analysis of different slips on the short circuit current of DFIGafter crowbar operation[J].Power System Protection and Control,2015,43(17):8-14.