Fault Distance Estimation of Coal-Mine Pulling Cables by Steady-State Electrical Measurements

The pulling cables employed in coal mines serve as power supply lines for electromechanical equipment. However, due to complex electromagnetic couplings among multiple conductors, it is difficult to locate faults in coal-mine pulling cables (CMPCs) based on existing circuit models and methods for ordinary ones. In this article, a fault distance estimation method is proposed for CMPCs. Aiming at multiconductor structure and parameters, the lump-parameter equivalent circuit models for analyzing electric quantities along the CMPC in both normal and fault conditions are constructed considering electromagnetic couplings among multiple conductors. The steady-state voltage and current at the fault point are then derived to create fault distance and resistance estimation functions. Finally, the experimental model of CMPCs is established by RTDS. Experimental results demonstrate that the voltage and current computational errors based on the constructed model do not exceed 0.5 V and 0.5 A, respectively. The maximum fault distance estimation error is lower than 13 m with various fault conditions, measurement errors, and noise interferences.