直流电压准无差修正的VSC-MTDC系统协同优化下垂控制  

Cooperative Optimal Droop Control for VSC-MTDC System with Quasi Non-error DC Voltage Regulation

作　　者：刘昊宇 刘崇茹 郑乐 王群乔 LIU Haoyu;LIU Chongru;ZHENG Le;WANG Qunqiao(State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources(North China Electric Power University),Beijing 102206,China)

机构地区：[1]新能源电力系统国家重点实验室(华北电力大学),北京市102206

出　　处：《电力系统自动化》2022年第6期117-126,共10页Automation of Electric Power Systems

基　　金：国家电网公司科技项目(SGXJJY00GHJS2000091)。

摘　　要：下垂控制凭借多站协同承担不平衡功率的优势,在多端柔性直流输电(VSC-MTDC)系统工程实践中广泛应用,其本质是改变直流电压实现直流潮流再分布来消纳不平衡功率,但直流电压偏离会影响系统安全经济运行。文中通过理论分析下垂控制方式下直流电压无差修正的不可行性,提出一种具备直流电压“准无差”调节能力的VSC-MTDC协同优化下垂控制策略,解决不平衡功率消纳引发的电压偏离问题。设计了附加直流电压控制器,自动调节功率参考值,改善动态过程中的直流电压。以扰动后电压源型换流器有功功率变化最小和直流电压距初始值最近为目标,优化下垂控制功率参考值增量,进行直流电压恢复。仿真研究表明,改进策略能平稳地实现以多个电压源型换流器功率变化最小为代价的直流电压全局最优调节,完成直流电压“准无差”修正。The droop control is widely used in the engineering practice of voltage source converter based multi-terminal high voltage direct current(VSC-MTDC) system by virtue of its advantages of multi-station coordination to undertake the unbalanced power. Its essence is to redistribute the DC power flow by changing the DC voltage for the unbalanced power accommodation, but the deviation of DC voltage will threaten the safety and economy of the system. Based on the theoretical analysis of the infeasibility of the non-error regulation of DC voltage in the droop control mode, this paper proposes a cooperative optimal droop control strategy of VSC-MTDC system with“quasi non-error”regulation ability of DC voltage to handle the DC voltage deviation caused by unbalanced power consumption. An additional DC voltage controller is designed to automatically adjust the active power reference value, which improves the DC voltage in the dynamic process. In order to obtain the minimum active power variation of the voltage source converter and the nearest DC voltage to the initial value, the reference value increment of droop control is optimized to implement the DC voltage recovery. Simulation results show that the improved strategy can smoothly perform the global optimal regulation of DC voltage at the cost of minimum power variation of multiple voltage source converters, and complete the“quasi non-error”regulation of DC voltage.

关 键 词：多端柔性直流输电系统 直流电压 下垂控制 协同优化控制 凸优化 免疫克隆选择算法 

分 类 号：TM721.1[电气工程—电力系统及自动化]