利用波前信息的直流输电线路超高速保护原理

HVDCtransmission raises demand for high-speed operation of relay. When a fault occurs, a large number of high-frequency signals are generated and transmitted to both ends of transmission line. Due to frequency-dependent characteristics of transmission line parameters, the high-frequency signals of the fault contain fault information. In this paper, the fault information contained in traveling wave front was analyzed on the basis of frequency-dependent characteristics of the transmission line parameters and broadband characteristics of fault point waveform. It is concluded that shape change of fault zero-mode current wave front is related to fault distance and the magnitude of fault zero-mode current wave front is related to fault resistance. Hence, a principle of ultra-high-speed protection for DC transmission line using waveform correlation coefficient is proposed. The simulation results show that the proposed method is fast, reliable and capable of anti-high transition resistance.