Fault property discrimination scheme in hybrid MTDC power system based on the amplitude distribution of injection signal

A fault property discrimination scheme for hybrid multi-terminal power systems is proposed to avoid blind reclosing under permanent fault and improve power supply reliability. The proposed scheme uses the amplitude distribution characteristics of the injection step voltage signal under temporary faults and permanent faults. The relationship between the measurement value and the calculation value of the injection signal is investigated for the distributed parameter models. A method for identifying single-end fault property based on measurement and calculation values is proposed. When a permanent fault is detected, the fault distance is determined by locating the voltage distribution calculation point along the line that equates to the measurement value at the remote end. The fault property discrimination scheme for adaptive reclosing is composed of fault detection and location methods. As demonstrated by simulation analysis under various fault scenarios, the proposed scheme is less affected by fault distance, fault resistance, sampling rate, and noise