中国电机工程学报2025，Vol.45Issue(17)：6625-6637,中插3,14.DOI:10.13334/j.0258-8013.pcsee.242155
基于负序控制特性差异的柔性低频输电线路采样值电流积聚量保护
Sampling Value Current Accumulation Protection for Flexible Low-frequency Transmission Lines Based on Differences in Negative Sequence Control Characteristics
摘要
Abstract
Based on modular multilevel matrix converter(M3C),low-frequency transmission system for offshore wind power(LFTS)faces the problem of insufficient sensitivity of differential protection for transmission lines due to weak feedback from dual power sources,and insufficient response speed of differential protection due to frequency reduction.In response to the above issues,based on the control characteristics of M3C and wind turbine converters,the coupling relationship between various sequence currents during asymmetric faults in the transmission line is analyzed.It is verified that there is a significant difference in the amplitude of negative sequence currents between the two sides of the fault line in the area.Based on this feature,a new principle of flexible low-frequency transmission line sampling value current accumulation protection based on the difference in negative sequence control characteristics is proposed.The new method can use accumulation operation to quickly amplify the different characteristics of negative sequence currents on both sides when asymmetric faults occur in flexible low-frequency transmission lines,greatly improving the speed of line protection action and ensuring reliability in external faults.Finally,an electromagnetic transient model of the wind farm transmission system via M3C is built in PSCAD,and the operational performance of the proposed protection method is verified by combining it with actual fault recordings on site.The results show that the proposed protection can quickly identify different types of internal and external faults,and the identification time of metal short circuit faults is less than 3 ms,with a maximum tolerance to 200 Ω for transition resistance.关键词
模块化多电平矩阵变换器/柔性低频输电/海上风电/控制特性差异/采样值电流积聚量/线路保护Key words
modular multilevel matrix converter(M3C)/flexible low-frequency transmission/offshore wind power/control characteristic differences/sampling value current accumulation/line protection分类
信息技术与安全科学引用本文复制引用
王书扬,周泽昕,杨国生,曹虹,陆翌,宋勇辉..基于负序控制特性差异的柔性低频输电线路采样值电流积聚量保护[J].中国电机工程学报,2025,45(17):6625-6637,中插3,14.基金项目
国家重点研发计划项目(2021YFB2401100) （2021YFB2401100）
国家电网有限公司科技项目(5211DS22002C).National Key R&D Program of China(2021YFB2401100) （5211DS22002C）
Science and Technology Project of State Grid Corporation of China(5211DS22002C). （5211DS22002C）
