混合多馈入直流系统VSC-HVDC和滤波器的无功协调控制

Reactive power coordinated control of VSC-HVDC and filter in hybrid multi-feed HVDC system

为了减少常规直流输电(LCC-HVDC)的滤波器投切,充分利用柔性直流输电(VSC-HVDC)的无功调节容量和其动态调节无功的优势,提出一种适用于LCC-HVDC和VSC-HVDC电气距离较近情况下的混合多馈入直流系统的无功协调控制策略。分别分析了LCC-HVDC和VSC-HVDC的无功控制原理及其控制特点,基于滤波器投切和VSC-HVDC两者的无功控制优势,设计了混合多馈入直流系统的无功协调两级控制模块,达到减少滤波器投切,抑制暂态低电压和过电压的目的。在PSCAD/EMTDC中搭建混合多馈入直流系统模型并进行仿真验证,仿真结果表明所提协调控制策略的控制效果优于VSC-HVDC采用定无功功率控制和定交流电压控制。

In order to reduce the filter switching of LCC-HVDC(Line Commutated Converter based HVDC)and make full use of reactive power regulation capacity of VSC-HVDC(Voltage Source Converter based HVDC)and its advantages of dynamic regulation of reactive power,a reactive power coordination control strategy in hybrid multi-feed HVDC system in which the electrical distance between LCC-HVDC system and VSC-HVDC system is close is proposed.The reactive power control principles and characteristics of LCC-HVDC and VSC-HVDC are analyzed.Based on the reactive power control advantages of filter switching and VSC-HVDC system,a reactive power coordinated two-stage control module is designed for the hybrid multi-feed HVDC system to reduce filter switching and inhibit transient low voltage and overvoltage.A hybrid multi-feed HVDC system model is built in PSCAD/EMTDC for simulation verification.The simulative results show that the control performance of the proposed strategy is better than that of VSC-HVDC with constant reactive power control and constant AC voltage control.