海上风电柔性直流输电换流变差动保护的适应性分析  

Adaptability analysis on differential protection of converter transformers in a VSC-HVDC transmission system connected to offshore wind farms

作　　者：程骁[1] 顾乔根[1] 任旭超 郑超[1] 黄涛[1] 张宝顺 CHENG Xiao;GU Qiaogen;REN Xuchao;ZHENG Chao;HUANG Tao;ZHANG Baoshun(NR Electric Co.,Ltd.,Nanjing 211102,China;State Grid Jiangsu Electric Power Co.,Ltd.,Nanjing 210024,China)

机构地区：[1]南京南瑞继保电气有限公司,南京211102 [2]国网江苏省电力有限公司,南京210024

出　　处：《浙江电力》2024年第3期8-18,共11页Zhejiang Electric Power

基　　金：国家重点研发计划资助项目(2021YFB2401100)。

摘　　要：海上风电柔性直流输电系统的故障特性有别于常规电力系统,因此常规继电保护方案应用于海上风电柔性直流输电系统时可能存在适应性不足的风险。分析了海上风电柔性直流输电系统故障情形下,不对称的电气量引发的谐波分量以及故障穿越过程中的负序抑制、限流措施对差动保护的影响。推导了计及序分量的差动保护灵敏度计算式并进行适应性分析,指出故障情形下的奇次谐波容易对差动保护产生影响,负序抑制及限流措施也将导致差动保护灵敏度下降。结合实际示范工程的仿真系统进行了大量仿真计算,结果表明,常规差动保护方案的灵敏性、可靠性均存在下降的问题。The fault characteristics of voltage source converter-based high voltage direct current(VSC-HVDC) transmission systems connected to offshore wind farms differ from those of conventional power systems.Consequently,there exists a potential risk of inadequate adaptability when conventional relay protection schemes are applied to the VSC-HVDC transmission system.This paper analyzes the impact of harmonic components induced by asymmetrical electrical quantities,negative sequence suppression,and current-limiting measures on the performance of differential protection during fault ride-through(FRT).Sensitivity calculation formulas for differential protection considering sequence components are derived,and adaptability analysis is conducted.It is noted that differential protection is susceptible to odd-order harmonics during fault conditions,while negative sequence suppression and current-limiting measures may also diminish its sensitivity.Extensive simulation calculations are carried out using a simulated system of a practical demonstration project.The findings indicate a decrease in the sensitivity and reliability of conventional differential protection schemes.

关 键 词：柔性输电 换流变压器 差动保护 谐波闭锁 灵敏度 

分 类 号：TM721.1[电气工程—电力系统及自动化] TM614