1.School of Electronic Information and Electrical Engineering,Shanghai Jiao Tong University,Shanghai,China;2.State Grid Zhejiang Yuyao Power Supply Company,Zhejiang,China
Youth Fund of NSFC；2019 Major Scientific Research and Innovation Project of Shanghai Education Commission
DC line protection is the key to ensure the safe and stable operation of the multi-terminal flexible DC distribution system. The main technical difficulty is the accurate identification and rapid isolation of fault section. The distribution characteristics of the transient high-frequency components in DC distribution network after fault are analyzed, and a pilot protection method based on the transient high-frequency power for DC lines is proposed. According to the amplitude change of the high-frequency power before and after the fault, the protection fast start criterion is proposed. According to the difference of linear relationship and correlation coefficient of high-frequency power on both sides of the line under different fault conditions, fault identification and pole selection criterion based on correlation coefficient of high-frequency power on both sides of the line is proposed. In MATLAB/SIMULINK, a multi-terminal flexible DC distribution network model is established. The simulation results show that the proposed protection method can quickly and accurately identify the fault line and fault pole with high sensitivity and reliability. Protection threshold is easy to design and not required for protection coordination of adjacent lines. Moreover, it has low requirements for data synchronization, and has good insusceptibility to fault resistance. Protection method is not affected by system operation mode and network topology.
CHEN Shaoyu,HUANG Wentao,TAI Nengling,et al.High-frequency Power Pilot Protection Method for Multi-terminal Flexible DC Distribution Network[J/OL].Automation of Electric Power Systems,http://doi.org/10.7500/AEPS20200105002.