Equivalent circuit application to a phase to ground fault detection in distribution networks without MV voltage measurements

A novel residual equivalent circuit (REC) for Petersen coil grounded distribution systems is presented. Load and fault position are taken into account by superposition of load and fault currents across the line, supply and fault impedances. An excellent equivalence has been found with EMTP full model. The new circuit is dedicated to on-line industrial applications, like fault parameter identification by comparison of measured residual currents with simulated ones. An example of such an application is shown.