A model of an intact power facility as an indicator of damage

Abstract

A general approach to the detection of faults in observed power system facilities is considered. An important property of the intact object model, namely, its capability of selecting the modes of the electric system that includes the protected object, is indicated. The entire set of the modes is divided into two subsets designated as the α and β modes. If it is in the α modes, the protected object is damaged, and, if it is in the β modes, it is in operating conditions. The selectivity of the relay protection is ensured by complete separation from the β modes. The model adequate to the intact power facility copes with this task. Upon damage to the object when the adequacy of the model is violated, the necessary prerequisites are created to ensure the acceptable sensitivity and speed of the relay protection. As an example, two power facilities are considered, i.e., a power-transmission line with one-sided monitoring and a three-phase transformer with a DYN winding connection. The β modes are faults outside the protected zone for the power-transmission line and magnetizing- current inrushes for the transformer.