Modeling of complex faults in electrical grids connected to traction substations

The study was aimed at developing digital models that would provide a means to accurately determine the operating parameters of electrical grids connected to traction substations in the event of complex faults. To this end, an approach was used based on a multiphase phase-coordinate representation of elements comprising the electric power system; this approach was implemented using the Fazonord AC DC software. The following types of complex faults were considered: downed power line; double line-to-ground fault at different points of the power line connected to a transformer with an isolated neutral point; two simultaneous short circuits in the grid. The modeling confirmed the need to factor in the traction network when determining operating parameters in the event of complex faults. For comparison, similar calculations were performed for the case of its disconnection. For a downed power line, the difference between the calculation results obtained with the traction network taken into account and for the case of its disconnection amounted to 11%. In the case of a double line-to-ground fault, the difference in power line currents reached 13%. For simultaneous short circuits in the grid with an isolated neutral point, the corresponding parameter was equal to 22%. Digital models of electric power systems were developed; these models enable the correct determination of operating parameters in the event of complex faults, taking the traction network into account. Their use in the design and operation of high-voltage electrical grids will enable the accurate setting of relay protection and automation devices, which, in turn, can reduce accident damage and power outage time for electricity consumers.