风电汇集地区SVC控制方式对电压异常振荡影响因素分析

随着风电渗透率不断升高,在大规模风电汇集地区由新投入静止无功补偿器(SVC)引发电压异常振荡的现象时有发生,引发了运行及研究人员的关注。基于典型大规模风电汇集地区无功电压控制现状,在DIgSILENT/PowerFactory中建立等效的系统模型,从SVC控制方式的角度出发,采用小干扰稳定特征值分析、时域仿真及波特图等不同稳定分析方法,对无功补偿装置恒电压和恒无功两种控制方式的适应性进行了比较与分析。并通过引入控制理论中对特定变量进行开环传递函数推导的方法,从新投入控制器的视角,以理论层面上对实际现场中新无功补偿控制器投入诱发振荡的现象进行了机理分析。研究结果表明:SVC不同控制方式随着系统变化的适应性不同,就系统已投入SVC风电场数目及系统阻抗方面的变化而言,对于大规模风电汇集地区的弱送端系统,无功补偿装置恒无功控制方式较恒电压控制方式的适应性更优。

Impact of SVC Control Mode on Voltage Abnormal Oscillation in Wind Power Influx Area

With the increasing penetration of wind power, abnormal voltage oscillation occurs frequently due to utilization of static var compensator(SVC)in large-scale wind power influx area, which attracts attention of researchers working on network planning and operation. An equivalent model of the system is established on the basis of reactive power and voltage control in typical large-scale wind power influx areas with software DIgSILENT/PowerFactory. Two main control modes of SVC, namely constant voltage control and constant reactive power control, are compared and analyzed via adopting different stability analysis methods including eigenvalue analysis in small signal stability, time-domain simulation and Bode plots. Moreover, the derivation method for open loop transfer function in control theory is introduced targeting certain variables. From the perspective of the new controller, the reason why oscillation occurred when it comes into use in actual wind farms is explained in theory. The results demonstrate that SVC with different control modes has different adaptability to the system''s change. In terms of the number of wind farm with SVC and the impedance of the system, the constant reactive power control mode performs better than the constant voltage control mode for weak sending end systems in large-scale wind influx area.