The aim of the thesis was to describe the problem of electromagnetic coupling between the power and telecommunications systems in the event of a single-pole short circuit, as well as the influence of the power plant on telecommunications lines and the protection of the telecommunications system from harmful electromagnetic influences on the power system. The first chapter of the thesis describes certain technical regulations for the introduction of telecommunications lines into power plants. The second chapter describes the basic characteristics of telecommunications networks and lines, and we get to know fiber optics in more detail, which are in the true sense of the word the telecommunications lines of the present and the future. They are broadband lines, and their transmission capacity is very large, and their basic raw material is silicon dioxide (quartz), which is found in nature in huge quantities and is not expensive. The third chapter discusses the protection of telecommunications lines when introduced into a power plant, because both the power and telecommunications networks are becoming increasingly dense, and thus their intertwining is also becoming greater. We distinguish three basic types of influence of power plants on TK lines, namely galvanic, inductive and capacitive influence, and we are interested in general protection measures in case of dangerous and disturbing influences. In the fourth chapter, calculation methods for the introduction of TK lines into power plants are described. In the event of a single-pole short circuit, the hazard voltage may be higher than the maximum permitted hazard voltage. However, the TK system can be threatened by overvoltage coming from the power grid side and overvoltage coming from the TK network side. Based on calculations and insights on the ground, it is sometimes suggested to introduce a translator. In the last chapter, the management of the electromagnetic coupling of the electric power, TK and traction system is described, where we have the electromagnetic coupling of the electromagnetic field and cable, in zero and differential mode, coupling via common impedance and coupling between two cables in differential mode.