含混合型MMC的多端柔性直流输电系统短路电流计算方法  

Short-Circuit Current Calculation Method for Multi-Terminal VSC-HVDC Transmission Systems with Hybrid MMC

作　　者：杨欢欢 杨荣照 王泽青 邱建[1] 付超 高琴 朱泽翔 姜拓 YANG Huanhuan;YANG Rongzhao;WANG Zeqing;QIU Jian;FU Chao;GAO Qin;ZHU Zexiang;JIANG Tuo(Power Dispatching and Control Center,CSG,Guangzhou 510663,China;Electrical Power Research Institute,CSG,Guangzhou 510663,China)

机构地区：[1]中国南方电网电力调度控制中心,广州510663 [2]南方电网科学研究院,广州510663

出　　处：《南方电网技术》2024年第7期63-73,共11页Southern Power System Technology

基　　金：国家自然科学基金资助项目(U22B600010)。

摘　　要：多端柔性直流输电系统中存在多个换流站,换流站之间复杂的耦合关系使得直流短路电流的计算成为一个难题。针对含混合型模块化多电平换流器(modular multi-level converter,MMC)的多端柔性直流系统应用场景,首先搭建了故障穿越前后混合型MMC的故障等效模型,并从混合型MMC直流故障穿越期间电路结构变化的角度出发,分析了直流故障穿越对多端柔性直流系统各支路短路电流的影响,在此基础上基于叠加定理提出直流故障穿越附加网络的概念。然后结合多端系统的近似解耦解析计算方法和直流故障穿越附加网络的概念,提出含混合型MMC的多端系统直流故障穿越期间的短路电流计算方法。最后,基于PSCAD/EMTDC平台的电磁暂态仿真结果表明,所提出的计算方法在故障发生6 ms内计算的短路电流值最大误差均在±6%以内,且具有良好的适用性,为含有混合型MMC的多端柔直系统的规划设计与保护整定提供了参考。There are multiple converter stations in a multi-terminal voltage source converter-high voltage direct current(VSC-HVDC)transmission system,and the complex coupling relationship among converter stations makes the calculation of DC short-circuit cur⁃rent a challenge.For the scenarios of a multi-terminal VSC-HVDC transmission system containing hybrid modular multi-level converter(MMC),firstly the fault equivalent model of the hybrid MMC before and after DC fault ride-through is established,and the influence of DC fault ride-through on the short-circuit current of the multi-terminal VSC-HVDC transmission system is analyzed from the perspective of the change in circuit structure during DC fault ride-through of a hybrid MMC.Based on the superposition theorem,the concept of DC fault ride-through additional network is proposed.Then,a short-circuit current calculation method of the multiterminal system containing hybrid MMC is proposed during DC fault ride-through,combining the approximate decoupling analytic calculation method of multi-terminal system and the concept of DC fault ride-through additional network.Finally,the electromagnetic transient simulation results based on PSCAD/EMTDC show that the maximum error of the short-circuit current values calculated within 6 ms of the fault occurrence is within±6%,and the proposed calculation method has good applicability.It provides a reference for the planning,design,and protection setting of multi-terminal VSC-HVDC transmission systems containing hybrid MMC.

关 键 词：多端柔性直流输电系统 混合型MMC 直流故障穿越 网络等效 短路电流计算 

分 类 号：TM721.1[电气工程—电力系统及自动化]