双闭环VF控制MMC输出短路电流特性分析与计算方法  

Short-Circuit Current Characteristics Analysis and Calculation Methods of Modular Multilevel Converter in Double Closed-Loop Voltage-Frequency Control

作　　者：陈怡静 李春华 李英彪 郭小江 王有超 张宇 陈双印 CHEN Yijing;LI Chunhua;LI Yingbiao;GUO Xiaojiang;WANG Youchao;ZHANG Yu;CHEN Shuangyin(China Huaneng Group Clean Energy Technology Research Institute Co.,Ltd.,Beijing 102209,China;School of Electrical and Electronic Engineering,Huazhong University of Science and Technology,Wuhan 430074,China;Huaneng Jiangsu Clean Energy Branch,Huaneng Power International,Inc.,Nanjing 210015,China;Wuhan New Energy Research Institute Co.,Ltd.,Wuhan 430034,China)

机构地区：[1]中国华能集团清洁能源技术研究院有限公司,北京市102209 [2]华中科技大学电气与电子工程学院,武汉市430074 [3]华能国际电力股份有限公司江苏清洁能源分公司,南京市210015 [4]武汉新能源研究院有限公司,武汉市430034

出　　处：《电力建设》2024年第10期90-99,共10页Electric Power Construction

基　　金：国家重点研发计划资助项目(2021YFB2400600);中国华能集团有限公司科技项目(HNKJ20-H54)。

摘　　要：新能源直接通过模块化多电平换流器(modular multilevel converter,MMC)孤岛送出时,MMC需要采用电压-频率(voltage-frequency,VF)控制方式,为新能源并网提供稳定的电压支撑。针对换流器交流侧发生三相对称短路故障时,对双闭环VF控制MMC输出的短路电流进行了精细化计算。结合系统电路特性和MMC控制特性,首先对VF控制MMC交流侧发生三相对称短路故障后换流器的节点特性进行了分析,研究表明故障后换流器可能表现类似电流源特性或电压源特性。在此基础上,提出了MMC呈电流源特性时短路电流超调量的计算方法,以及MMC呈电压源特性时短路电流直流分量和稳态量的计算方法。最后,在PSCAD平台上进行了仿真分析,验证了所提出方法的正确性。When a modular multilevel converter(MMC)is connected to an islanded renewable power system,voltagefrequency control must be adopted to provide stable voltage support.This study focuses on the calculation of the short-circuit current of an MMC in the double closed-loop voltage-frequency mode after a three-phase symmetrical short-circuit fault occurs.Considering the circuit and control system characteristics,this study first analyzes the output characteristics of a MMC after a fault occurs and proposes that the MMC can be represented as a current source or a voltage source.Then,calculation methods are proposed for the short-circuit current overshoot when the MMC is represented as a current source and for the short-circuit current DC component when the MMC is represented as a voltage source.Simulations are conducted using PSCAD to verify the accuracy of the proposed method.

关 键 词：模块化多电平换流器(MMC) VF控制 短路电流 计算方法 

分 类 号：TM72[电气工程—电力系统及自动化]