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  

Short circuit current calculation method of power system integrated with DFIG based on equivalent sequence circuits

作　　者：张金华[1] 张保会[1] 陈琳浩 郝治国[1] 

机构地区：[1]西安交通大学电气工程学院,陕西西安710049

出　　处：《电力自动化设备》2018年第1期19-25,共7页Electric Power Automation Equipment

基　　金：国家自然科学基金资助项目(51277143)~~

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.

关 键 词：双馈风电机组 撬棒保护 短路电流 序网电路 等值电路 转速频率 

分 类 号：TM614[电气工程—电力系统及自动化]