Active Filters in the Power Supply of Electrified Railway Applications

In recent years, there has been an increase in non-linear electrical loads in power supply networks. This is due to the increase in the proportion of alternative energy sources, microprocessor equipment, and semiconductor devices. This inevitably leads to a deterioration in the quality of electrical energy. As a result, the service life of electrical equipment is reduced, and there are cases of unreasonable operation of relay protection devices. This article explores the use of an active filter to improve the quality of the power supply in electrified rail applications. Basic research methods are analytical review, mathematical analysis, modeling, and simulation of power supply systems with an active filter. The use of an active filter reduces the THD from 21.31% to 1.7% with a sample time of 0.5 µs. As a result of the research, the advantages and disadvantages of this method were identified to improve the quality of electrical energy, and alternative methods were proposed.