新能源经电网换相型换流器高压直流输电系统(line commutated converter high voltage direct current,LCC-HVDC)连续换相失败将引起送端暂态过电压,严重威胁新能源并网安全稳定运行.首先分析连续换相失败影响因素及其对新能源并网侧过电压的影响;然后结合换相失败故障预测环节,提出一种改进直流电流与逆变侧触发角指令的协同控制策略,同时减小直流电流和增大触发角抑制连续换相失败与送端暂态过电压;最后在PSCAD/EMTDC仿真软件中搭建基于CIGRE直流输电模型的新能源直流外送系统仿真模型进行验证.仿真结果表明所提协同控制策略能够有效抑制直流输电系统连续换相失败与送端过电压.
Cooperative Control Strategy for Suppressing Continuous Commutation Failure of New Energy Through DC Transmission System
Continuous commutation failure of new energy through LCC-HVDC DC transmission system will cause transient ov-ervoltage at the sending end,which seriously threatens the safe and stable operation of new energy connected to the grid.The in-fluence factors of continuous commutation failure and its influence on over voltage of new energy grid connection point are first-ly analyzed.Then,combined with the prediction of commutation failure,a cooperative control strategy is proposed to improve the DC current and trigger angle instruction on the inverter side.Simultaneously,reducing the DC current and increasing the trigger Angle to suppress the continuous commutation failure and transient overvoltage at the sending end.Finally,CIGRE DC trans-mission standard model by PSCAD/EMTDC simulation software is used to verify the research.The simulation results show that the proposed cooperative control strategy can effectively suppress the continuous commutation failure and the over voltage of the sending end.
line-commutation converterscontinuous commutation failuretransient over-voltagecooperative control
万方数据
维普
