由于弱交流系统电压对无功功率变化极为敏感,换流站内静止同步无功补偿器(static synchronous compensatory,STATCOM)与直流的控制若协调不当,故障后直流功率过快恢复会引起换流站的无功功率失衡、电压畸变、连续换相失败等严重问题,对直流稳定运行产生较大影响.分析了落点弱交流系统故障后直流的恢复问题,提出了一种STATCOM与直流系统的电压指令限制单元(voltage dependent current limiting,VDCOL)综合优化的方法,搭建了STATCOM与直流联合运行的RTDS仿真模型并开展仿真与现场实验验证.结果表明所提出的优化方法可限制故障后直流电流超调,减少无功功率消耗.同时直流恢复时间适当延长以及STATCOM的有效配合有利于交流电压恢复和减少后续换相失败风险,对提高弱受端交流系统中直流稳定运行的效果明显.
Study on the Optimization of Large Capacity STATCOM and Weak Receiving-End VDCOL Coordinated Control Strategy in HVDC
The AC voltage is very sensitive to the change of reactive power in weak AC systems.If the both control of STATCOM and HVDC in the converter station is not coordinated properly,too fast recovery of DC power after the failure will lead to serious is-sues such as reactive power imbalance,voltage distortion,repeated commutation failures,which will have a great impact on the stable operation of HVDC.The paper analyzes the problems of HVDC recovery after the failure of weak AC system,proposes a comprehensive optimization method of VDCOL for STATCOM and HVDC system,builds a RTDS simulation model for joint opera-tion of STATCOM and HVDC,and carries out simulation and field experiment verification.The results show that the proposed optimization method can limit the DC current overshoot,reduce the reactive power consumption.Meanwhile the appropriate exten-sion of DC recovery time and the effective cooperation of STATCOM are beneficial for AC voltage recovery and reduce subsequent commutation failures,and have a significant effect on improving DC stable operation in the weak receiving-end.
STATCOMHVDCweak receiving-endcoordinated controlreal time simulationVDCOL
万方数据
维普
