Calculation of three-phase bolted short-circuit currents in a MV distribution feeder with induction and synchronous generators

It is well-known that co-ordination of protective devices and fault localization techniques in active distribution networks require results of various short-circuit (SC) analyses in the time domain. Accordingly, the main aim of this paper is to calculate the three-phase bolted SC current in the time domain for a radial medium voltage (MV) feeder, which is connected to a MV distribution network, and which has one induction generator (IG) and one synchronous generator (SG) at two different locations. The SC analysis of this concrete case study can be regarded as a novelty. The SC analysis is based on the well-known equivalent circuit models for the MV distribution network, IG and SG, as well as the applications of Kirchhoff’s laws and the theorem of superposition. In addition, the proposed analysis method enables calculation of the SC current in the cases where the arc resistance at the fault location cannot be neglected. Finally, the results showed that there are no limitations on the application of the proposed method to the task of calculating asymmetrical SC currents.