SVC和IPC联合改善异步机风电场的电压稳定性

Improvement of Voltage Stability of Asynchronous Wind Farms Based on SVC and IPC

为了改善异步机风电场的电压稳定性,在分析风电场电压失稳原因的基础上,提出将静止无功补偿器SVC和相间功率控制器IPC联合引入风电场并网系统中。将SVC并联于风电场母线,提供无功功率;将IPC串联于风电场联网线路上,在分析IPC基本结构的基础上,推导出相间功率控制器限制短路电流的条件。在系统侧发生短路时,IPC可以起到限制短路电流、降低风电出口电压跌落的作用,提高电压稳定性。通过Matlab/Simulink软件平台搭建了风电场并网的仿真模型,结果表明:异步机风电场在风速随机波动的情况下,SVC能动态补偿无功功率,保持系统电压稳定性;当系统中出现三相短路接地故障时,IPC良好的短路电流限制能力使得母线电压不至于降得太低,能保持电压稳定,提高了风电机组的低电压穿越能力。

In order to improve the voltage stability of the asynchronous wind farms, on the basis of analyzing the reason for the wind farm voltage instability, static var compensator （SVC） and inter-phase power controller （IPC）are intro- duced into wind power grid system. The reactive power is provided by SVC paralleling in the wind farms bus, and the IPC is connected in series on the wind farm network lines. Based the analysis of the basic structure of IPC, the condi- tions of IPC to limit short circuit current is deduced. When the short circuit occurs on the system side, the IPC can limit short circuit current, reduce voltage drop at wind power export, which improves the voltage stability. A simulation mod- el of wind power grid is built in Matlab/Simulink, and the simulation results show that when the wind speed is in ran- dom fluctuation, the reactive power can be compensated by SVC to maintain the transient voltage stability dynamically ; when there is three-phase short-circuit ground fault in the system, the IPC can limit the short circuit current so that the bus-bar voltage can not fall too low, maintaining the voltage stability and improving the ability of low voltage ride- through of wind turbines.