Analysis of Fault Component Characteristics and Protection Applicability on Flexible Low Frequency Transmission System
Due to the change of operating frequency and the control mechanism of flexible low-frequency converter sta-tion,the fault characteristics of flexible low-frequency transmission system and its influence on protection principle are complicated.In order to analyze the applicability of fault component protection principle in flexible low-frequency trans-mission system,a double-terminal low-frequency transmission model with fault current limiting as fault control strategy is established based on the control architecture of flexible low-frequency converter station.After considering the control characteristics of the system when three-phase fault occurs in the line,the impedance characteristics of low-frequency fault component in different situations are analyzed,and the quantitative calculation formula of low-frequency equivalent impedance is deduced,and then the influence mechanism on traditional fault component protection components is ana-lyzed theoretically.Finally,a double-terminal low-frequency transmission model is built on PSCAD/EMTDC platform to verify the theoretical analysis.The research results show that the flexible low-frequency transmission system can reduce the protection range of fault components and even completely fail the protection components under certain fault condi-tions,which has a certain reference for the development of relay protection research in low-frequency systems.
low frequency transmission systemfault componentcontrol characteristicsimpedance characteristicdis-tance elementdirectional element
国家科技期刊平台
NSTL
万方数据
