Prony´s method: an efficient tool for the analysis of earth fault currents in Petersen-coil-protected networks

Prony´s method is a technique for estimating the modal components present in a signal. Every modal component is defined by four parameters frequency, magnitude, phase, and damping. This method is used to analyse earth fault currents in Petersen-coil-protected 20 kV networks. The variations of Prony´s parameters in terms of some of the power systems characteristics (distance between the busbar and the fault, fault resistance and capacitive current of the whole network) are presented. It is shown that some of the Prony´s parameters relating to the fault current transient may be useful to determine what kind of fault occurred, and where it occurred