Active Detection Method For Fault Identification of LVDC Distribution Network

This paper proposes an active fault detection method based on harmonic injection. First, the single-pole ground fault equivalent circuit of the low-voltage DC distribution network is established, the single-pole ground fault characteristics of the low-voltage DC distribution network are theoretically derived, and the voltage and current dynamic characteristic equations after the fault are determined. Based on this fault characteristic, a harmonic signal global injection method for active fault identification is proposed to extract the harmonic voltage and current signals after the fault, and use the impedance characteristics to locate the fault. This article not only gives the fault detection process, but also describes in detail the injection method and selection principle of the harmonic signal as well as the derivation process of the quadratic curve fitting and ranging method. Finally, a simulation model was built in MATLAB/Simulink to confirm that this method can accurately identify fault locations while ensuring power quality.