In the AC-DC interconnection system,each DC transmission channel can produce large power loss while transmitting a large amount of electric energy.By coordinating and optimizing the voltage and reactive power control measures of multi-circuit extra/ultra HVDC transmission system,the power loss of the whole AC-DC system can be effectively reduced.This paper presents a multi-objective reactive power optimal control method for AC-DC system considering the detailed power loss characteristics of the converter stations.A multi-objective reactive power optimal control model for AC-DC interconnected system is established to minimize the total loss of the whole AC-DC transmission system including the loss of the main equipment in the converter stations and the sum of the squared voltage deviation of all key nodes.An adaptive weighted sum algorithm is presented,which is combined with the GAMS/CONOPT solver to obtain the evenly distributed Pareto optimal solutions set for the multi-objective optimization problem.According to the fuzzy membership and entropy weight of each Pareto optimal solution,the compromised optimal solution is determined from the Pareto optimal frontier curve,which is used as the multi-objective reactive power optimal control scheme.Test results of a 6056 bus AC-DC interconnection system show that Pareto optimal solutions set obtained from the proposed method is evenly distributed,and the obtained multi-objective optimal control scheme can effectively reduce the operational power loss of the converter stations and improve the voltage quality of key nodes.%交直流互联系统中各个直流输电通道在输送大量电能的同时,也会产生很大的电能损耗.通过协调优化多回超/特高压直流输电系统的电压无功控制措施,能够有效地降低整个交直流系统运行的损耗电量.提出一种考虑换流站详细损耗特性的交直流系统多目标无功优化控制方法,以包括换流站内部各主要设备损耗的整个交直流输电系统总网损和所有关键节点电压偏差平方和的最小化为目标,建立交直流互联系统的多目标无功优化控制模型.提出一种自适应加权和算法,结合GAMS/CONOPT解法器求解得到多目标优化问题的均匀分布的帕累托最优解集.并根据各个最优解的模糊隶属度和熵权信息从帕累托前沿曲线中确定出折中最优解,作为多目标无功优化控制方案.通过对某个6056节点交直流互联系统的计算表明,所提出的算法求得的帕累托最优解集分布均匀,且所获得的多目标无功优化控制方案能够有效降低换流站运行损耗,提高关键节点的电压质量.
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