An automatic system to locate phase-to-ground faults in medium voltage cable networks based on the wavelet analysis of high-frequency signals

The paper presents a microcontroller-based automatic system that applies the continuous wavelet analysis to the measured fault-originated electromagnetic transients in order to locate phase-to-ground faults in power distribution networks composed by coaxial cables. The paper describes the numerical procedure conceived to: (i) detect the presence of fault-originated transients superimposed to steady-state voltage waveforms, (ii) identify the faulted phase-conductor and (iii) identify the part of the fault transient that can be used to build a specific mother wavelet so to improve the fault location accuracy. The paper also describes the implementation of the procedure into an embedded microcontroller as well as its experimental validation carried out by means of analog real-time generated fault waveforms obtained from EMTP simulations.