Managing post-fault oscillation phenomenon in compensated MV-networks

Post-fault oscillations have recently been identified as being one of the main causes of maloperations of earth-fault protection in compensated MV-networks [1]. Until now, the theory regarding post-fault oscillation condition has been missing from `classical' earth-fault protection analysis, e.g. [2], where only healthy-state, inside and outside fault conditions have been considered. This paper adds this `missing piece of the puzzle' and presents the necessary theory and hand-calculation equations to analyse the post-fault oscillation condition from earth-fault protection perspective in the level required by a protection engineer.