Study of local faults in cables based on input impedance spectra

The large-scale laying of cables has accelerated the development of power systems, and the voltage level is increasing, while the traditional cable fault detection-pulse current experimentation (ICE), time domain reflectometry (TDR) and other methods in fault diagnosis have the problems of insufficient accuracy and limited fault type identification. Insufficient accuracy and limited fault type identification, so a cable local fault diagnosis method based on cable input impedance spectrum is proposed. Firstly, we analyse the shortcomings of traditional detection methods, and clarify the basic principle of the input impedance method and the fault identification method on the basis of the power cable distribution model. Then, we analyse the changes of the input impedance spectrum during different types of faults (open circuit, short circuit, high resistance, low resistance) in power cables, and judge them by combining with the frequency-domain diagrams, based on which, we verify the characteristics of the input impedance spectrum under the fault conditions through simulation. Finally, the error compensation is carried out for the simulation experiment to improve the accuracy of fault diagnosis. The final results show that the method used in this paper has good accuracy and better fault identification performance.