柔性直流输电系统的黑启动控制能力研究

柔性直流输电系统中的可关断器件具有自关断能力,能够对开通、关断时刻进行控制,可以与无源系统连接进行换流。本文针对VSC在无源逆变方式下不需要外加换相电压的快速恢复控制能力,研究了柔性直流输电系统的黑启动控制能力。设计了黑启动过程中VSC-HVDC送端换流站控制策略采用定直流电压/定无功功率控制,受端换流站控制策略采用定交流电压/定频率控制,研究了电源并网时控制策略协调优化对黑启动的作用。以Kunder四机两区域系统为例,对整个黑启动过程在PSCAD/EMDTC中进行了仿真,研究表明本文采用的控制策略具有良好的电压、频率特性,完成了黑启动的实现。

Study on Control Capability of Black-start in VSC-HVDC System

IGBT in VSC-HVDC system has turn-off capability,can control the turn-off time,and also can connect with passive system.The control ability of black-start in VSC-HVDC system is studied as to the fast recovery control ability of VSC without additional commutation voltage in the passive inverter mode.In the process of black-start,constant DC voltage / constant reactive power control strategy is used as to control VSC-HVDC rectifier converter,and constant AC voltage / constant frequency control strategy is used as to control VSC-HVDC inverter converter.In addition,the impact of coordination and optimization of control strategy on black-start is studied when generations are connected to power grid.By taking Kunder’s four-machine two-area system as an example,the entire process of black-start is simulated by using of PSCAD/EMDTC,and simulation study shows that the proposed control strategies has excellent voltage and frequency characteristics during the realization of black-start.