适用于VSC-MTDC的改进直流电压下垂控制策略  

Improved Voltage Droop Control Strategy for VSC-MTDC

作　　者：孙黎霞[1] 陈宇[1] 宋洪刚 曹红[1] 王琦[1] 

机构地区：[1]河海大学能源与电气学院,江苏省南京市211100 [2]国网浙江东阳市供电公司,浙江省东阳市322100

出　　处：《电网技术》2016年第4期1037-1043,共7页Power System Technology

基　　金：国家自然科学基金资助项目((51137002;51190102);国家重点基础研究发展计划(973计划)(2013CB228204)~~

摘　　要：针对电压源型换流器的海上风电场多端直流并网(VSC-MTDC)系统,提出一种考虑换流站间直流电压偏差的改进电压下垂控制策略,结合电压裕度控制和电压下垂控制的优点,引入2个控制参数,修正了换流站的直流电压与有功功率的特性曲线。在实现直流电压调节和有功功率平衡目标的基础上,有效缩短了换流站控制模式切换过程的暂态过渡时间,以防止直流电压不受控。控制器响应速度快,提高了电网的暂态稳定性。在PSCAD/EMTDC仿真平台上搭建了海上风电场5端VSC-HVDC并网模型,分别对换流站功率越限和风电场风速变化进行仿真,验证了提出控制策略的有效性。On account of voltage source converter-based multi-terminal direct current（VSC-MTDC） transmission systems for offshore wind farms, an improved voltage droop control strategy is proposed considering dc voltage deviation between converter stations. Combining merits of voltage margin control and voltage droop control, dc voltage and active power characteristics of VSC station is modified by introducing two controllable parameters. The proposed control strategy can regulate dc voltage and balance active power, reduce transient transition duration, and minimize period of uncontrolled dc voltage when control mode of converter station is switched. Consequently, quick response of controller is achieved, and transient stability of power grid is guaranteed. A five grid-connected terminal VSC-HVDC for offshore wind power farm is simulated with PSCAD/EMTDC. Two simulation scenarios are presented, i.e. active power exceeding limitation in one VSC station and wind speed variation in wind farm. Results verify effectiveness and feasibility of the proposed strategy.

关 键 词：电压源型多端直流输电 改进电压下垂控制 直流电压偏差 暂态过渡过程 

分 类 号：TM71[电气工程—电力系统及自动化]