Modeling and analysis of short-circuit currents of a 1×25 kV traction power supply system in the SimInTech program at various stages of voltage regulation of the OLTC device

Abstract

Calculations of short-circuit currents in traction power supply systems are performed for the correct selection of equipment characteristics of both the contact network and traction substations. In addition, such calculations are necessary for the correct selection and configuration of relay protection devices. Therefore, modeling the short circuit mode is relevant. Short circuit is an emergency mode that is dangerous for the equipment, and incorrect selection of characteristics entails instant failure of the equipment at the first short circuit. It is important to calculate the short circuit mode most accurately, taking into account the many factors and devices that can affect the flowing currents. One of these devices is a voltage regulation device under load, which allows to adjust the voltage on the lowest voltage winding of a traction transformer without disabling it. The SimInTech dynamic simulation environment was chosen to simulate the short circuit mode, taking into account the possible variable voltage. This program allows to create combined models that take into account many factors, including transients, which in particular occur during short circuits. As a result of the simulation, oscillograms of currents at the short-circuit point, at the inputs of the high voltage of the traction transformer, on the feeders of the contact network and directly at the short-circuit point were obtained. The article evaluates the program as an environment for modeling traction power supply systems, analyses the effect of voltage regulation under load on short-circuit currents and the effect of short-circuit currents on the reliability of a voltage regulation device under load.