Analysis of faults in active distribution network with and without synchronous generator using instantaneous symmetrical components in time domain

摘要

The paper demonstrates the application of instantaneous symmetrical components method for the analytical calculation of all types of short-circuit currents in faulted distribution feeder with and without three-phase synchronous distributed generation (DG) connected. In active distribution systems, time-domain short-circuit current analysis is required in the processes of protective devices coordination and fault localization. In terms of the impact on the fault current, synchronous generator is the most critical DG type. The method enables encompassing initial conditions (load currents and voltages) before the fault occurs, critical conditions at the moment of fault occurrence, shunt parameters of network elements and the degree of voltage unbalance present in the feeder. Also, the procedure that we propose enables calculation of short-circuit current when the fault arc resistance cannot be neglected. Comparison with results of the fault current calculations based on the IEC methodology was performed through simulation tests and results.