FHMMC特高压直流输电系统中串联换流阀组启动充电策略  

Start-up Charging Strategy for Series-connected Converter Valve Groups in UHVDC Transmission System Based on Hybrid FHMMC

作　　者：胡雨龙[1] 邹常跃 周竞宇 HU Yulong;ZOU Changyue;ZHOU Jingyu(Extra High Voltage Power Transmission Company,CSG,Guangzhou 510663,China;State Key Laboratory of HVDC,Electric Power Research Institute,CSG,Guangzhou 510663,China)

机构地区：[1]中国南方电网有限责任公司超高压输电公司,广州510663 [2]直流输电技术国家重点实验室(南方电网科学研究院),广州510663

出　　处：《高电压技术》2023年第4期1582-1590,共9页High Voltage Engineering

摘　　要：800k V昆柳龙直流工程在两个受端换流站采用对称双极高低端阀组串联的全半桥子模块混合型模块化多电平换流器。在不同的充电工况下,因全桥子模块(fullbridgesub-module,FBSM)和半桥子模块(halfbridge sub-module,HBSM)器件及其模块化串联的桥臂支路充电特性不同,造成两种子模块电容电压难以平衡,导致阀组及系统无法启动解锁。提出了特高压柔直系统中全半桥子模块混合式模块化多电平换流器(full and half bridge hybrid modular multilevel converter,FHMMC)串联阀组在直流侧不短接和短接两种方式下的启动充电策略,针对不同工况下相应导通FBSM T_(3)、T_(4)管和HBSM T_(2)管,强制转换充电路径和充电对象,实现两种子模块电容均衡充电。针对直流侧不短接时后充电阀组FBSM感应带负压问题,研究并提出了极充电顺控策略,通过缩短阀组充电时间间隔来减少后充电阀组负压幅值。上述启动充电策略经过现场试验验证并用于工程实际。FHMMC with symmetrical bipolar and dual converter valve groups in series are adopted at two receiving-end converter stations of±800 kV Kun-Liu-Long VSC-UHVDC project.Under different charging conditions,due to the different charging characteristics of FBSM and HBSM and their modular series branches,the capacitance voltage of sub-modules is difficult to balance,resulting in the failure of start-up and deblocking for converters.In this paper,the start-up and charging strategy for series FHMMC converter valve groups under conditions of short-circuit and non short-circuit at DC sides is proposed.FBSM T_(3),T_(4) and HBSM T_(2) are triggered for different conditions,respectively,and charging path and object are forcibly converted to realize the balance charging for capacitance.A pole charging sequence control strategy is proposed to reduce the negative voltage of the second converter valve group which is charged by the first converter valve group through the stray circuit.The start-up and charging strategy is verified by field tests and can be used in engineering practice.

关 键 词：混合型模块化多电平换流器 特高压柔性直流 启动充电 串联阀组 全桥子模块 半桥子模块 

分 类 号：TM721.1[电气工程—电力系统及自动化]