真双极VSC-MTDC风场侧换流站软切换控制策略  

Soft switching control strategy of true bipolar VSC-MTDC wind field side converter station

作　　者：刘文胜 王海云[1] 黄新民 王祥君 LIU Wensheng;WANG Haiyun;HUANG Xinmin;WANG Xiangjun(School of Electrical Engineering,Xinjiang University,Urumqi 830046,China;State Grid Xinjiang Electric Power Co.,Ltd.,Urumqi 830063,China)

机构地区：[1]新疆大学电气工程学院,新疆乌鲁木齐830046 [2]国网新疆电力有限公司,新疆乌鲁木齐830063

出　　处：《电力科学与技术学报》2023年第5期87-97,共11页Journal of Electric Power Science And Technology

基　　金：国家重点研发计划(2021YFB1507005);新疆维吾尔自治区重点研发计划(2020B02001)。

摘　　要：真双极多端柔性直流输电(voltage source converter based multi-terminal direct current,VSC-MTDC)新能源侧换流站正、负极换流器可独立控制。针对定交流电压幅值频率控制(U/f控制)换流器发生故障,将定有功无功控制(P/Q控制)换流器的控制策略转换为定U/f控制时交直流母线电压波动较大,严重时可能会造成新能源场站脱网这一问题,建立统一切换控制模型,在统一切换控制模型基础上引入基于电流跟随的软切换控制策略,实现切换瞬间内环电流参考值同步。基于PSCAD/EMTDC搭建大规模新能源接入的四端真双极VSC-MTDC系统,经稳态、风电场功率波动、换流器单极闭锁运行工况下的仿真,验证了换流站对新能源接入的电压支撑和系统切换过程中电力系统平滑过渡的能力,为进一步提高真双极VSC-MTDC系统控制灵活性提供了参考。True bipolar multi-terminal flexible DC transmission voltage source converter based multi-terminal direct current(VSC-MTDC)new energy side converter station positive and negative converters can be controlled independently.In view of the failure of the converter with constant AC voltage amplitude and frequency control(U/f control),the control strategy of the converter with constant active and reactive power control(P/Q control)is converted into the AC and DC bus voltage under constant U/f control in this papers.Causing the problem that the fluctuation is large and the new energy station would be disconnected from the grid in severe cases.A unified switching control model is established,and a soft switching control strategy based on current following is introduced on the basis of the unified switching control model to realize the reference value of the inner loop current at the moment of switching synchronization.Based on PSCAD/EMTDC,a four-terminal true bipolar VSC-MTDC system with large-scale new energy access is built.Through the simulation under steady state,wind farm power fluctuation,and converter unipolar blocking operation,it is verified that the converter station has a voltage support of new energy access and the ability of smooth transition of the power system during the system switching process provide a reference for further improving the control flexibility of the true bipolar VSC-MTDC system.

关 键 词：多端柔性直流 真双极 换流器 软切换 

分 类 号：TM723[电气工程—电力系统及自动化]