张北柔性直流电网运行方式转换风险分析及预防措施  

Risk Analysis and Prevention Measures of Operation Mode Transformation for Zhangbei VSC-based DC Grid

作　　者：林少伯 李新年 雷霄 谢国平 贺郁文 杨立敏 LIN Shaobo;LI Xinnian;LEI Xiao;XIE Guoping;HE Yuwen;YANG Limin(National Key Laboratory of Power Grid Safety(China Electric Power Research Institute),Haidian District,Beijing 100192,China)

机构地区：[1]电网安全全国重点实验室(中国电力科学研究院有限公司),北京市海淀区100192

出　　处：《电网技术》2023年第10期4017-4025,共9页Power System Technology

基　　金：国家电网有限公司总部管理科技项目(5100-202155345A-0-0-00):“多类型直流馈入的高比例新能源电力系统稳定特性及对策仿真研究”。

摘　　要：柔性直流电网运行方式灵活多样,供电可靠性高,在运行过程中运行方式之间的转换必不可少。对于采用金属返回线的双极柔性直流电网,若以站内接地网作为接地点,可能在不同运行方式转换过程中存在风险。以张北柔性直流电网工程为例,研究了柔性直流电网工程运行方式转换或接地点转换过程中金属回线电流分配规律,分析了金属回线操作顺序不当引起的方式转换风险;根据转换风险分析结果,提出了柔性直流电网方式转换过程增加金属回线和接地点联锁建议及运行方式转换的操作建议,通过张北柔性直流电网工程数模混合仿真平台验证了所提出措施的正确性,且该建议措施已应用于张北柔性直流电网工程,为柔性直流电网工程的调度、运维提供重要的技术指导。A VSC-based DC grid has flexible and diverse operation modes with high reliability of power supply.The transformation in different operation modes is essential during operating.If taking the ground grid of a converter station as the earthing point of the VSC-based DC grid with metallic return lines,a risk of DC grid tripping may take place when the operation mode transfers to another.The distribution regularity of the metallic return line currents is studied when the operation mode or the earthing point transfers in this paper.Then the transfer risk is analyzed due to the incorrect operating sequence of the metallic return lines.According to the results of the transfer risk analysis,suggestions are proposed on the addition of the interlock between the metallic return lines and the grounding points and the transferring sequence for the operation mode transformation.The proposed preventive measures are verified in the digital-analog hybrid simulation system and used in Zhangbei VSC-based DC grid project,which will become an important technical guidance for the power dispatching and operating of the VSC-based DC grid project.

关 键 词：柔性直流电网 运行方式 金属回线 接地点转换 

分 类 号：TM721[电气工程—电力系统及自动化]