Analysis of Measures that Exclude the Non-Selective Actions of Differential Collecting Busbar Protection in External Two-Phase Short Circuits with the Saturation of Current Transformers Included in Fault-Free Phases

Abstract

An analysis is made on the non-selective actuation of the differential protection of busbars with a voltage of 110 kV of an electrical distribution system substation in the transition mode of an external two-phase short circuit. The protection effect is found to be due to the saturation of the transformer cores of class P current included in fault-free phases. Methods are also analyzed to ensure the correct operation of protection in the considered mode, and methods for calculating the protection parameters at which these methods are workable are proposed.