Purpose: false tripping on the supply lines of the contact network when passing an insulating interface leads to dangerous situations on the railroad, e.g. annealing and burning of contact wires, arcing. Also false disconnections can lead to stoppage of rolling stock on the guiding gradient and, thus, reduce throughput and transportation capacity. To solve the problem, namely to exclude false tripping of fast-acting switches, the paper proposes a method of using GPS/GLONASS transmitters to improve protection devices on supply lines. Methods: the research is carried out on the basis of theoretical knowledge of new developments related to geopositioning of rolling stock, theory of electric and magnetic circuits and theory of traction power supply. Results: this paper formulates and studies the concept of loading the set point of feeder line protection devices based on the data of current collector location on the electric rolling stock relative to the isolating coupling. Also each block of the complex of devices and principles of their operation are described in detail. The graphs of change of current setting of fast-acting switches are constructed and the variant of modernization of their design for operative change of current setting is offered. Practical significance: the result of the work is of importance, first of all, for ensuring reliability, uninterrupted operation of the traction power supply system and increasing the throughput and carrying capacity. The presented work sets a new direction for the development of protection devices in the DC traction power supply system using a new type of transmitted data – the geographical position of the rolling stock. Thus, the work demonstrates the possibility of introducing new technologies for determining the position of the object in the relay protection system of the contact network.