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In this paper, the possibility of increasing the transmission capacity of power transmission lines 35 to 220 is considered. The methods of phase convergence and splitting are considered as known methods for increasing the capacity of power transmission lines, The use of insulating cross-arms and spacer blocks mounted between the wires of different phases, allows to bring the phases of power transmission lines together, thereby reducing the longitudinal reactance of the line and increasing the transverse capacitance. Similarly, by splitting the wires, it is possible to get the same results. The studies were carried out on the basis of an analysis of the equations determining the parameters of power transmission lines. The use of insulating cross-arms and spacer blocks allows not only to increase the transmitted power, but also to reduce the dimensions of power transmission lines and the alienation of land under it, to reduce the environmental impact. Increasing the capacity of power transmission lines will reduce the electric power network, thereby increasing its reliability and manageability.

In this paper, a method of samples of instantaneous currents and voltages is proposed, which allows to extract only sinusoidal information necessary for correct operation of digital relay protection and automation from information containing instantaneous values of currents containing periodic and aperiodic components. The studies were performed based on the analysis of the equations of short-circuit currents in electrical networks. The time during which the current and voltage parameters are sampled does not exceed 2 milliseconds, which is less than 1/8 of the industrial frequency period. The method made it possible to implement protections, which fix damage with a help of analog devices only for several periods of current change. At the same time, the protections implemented by analog devices are not free from errors introduced by aperiodic components. Principles for the implementation of directional protection of generators and transformers are proposed. Directional protection of generators and transformers is feasible in the presence of information about the modes of the electrical network elements that are connected with the protected ones. The proposed four-sampling method allows to implement all protections that react to periodic components of currents and voltages using only four instantaneous values of currents and voltages obtained within two milliseconds or less after the occurrence of a short circuit.

One of the serious problems of the normal operation of power systems is a violation of efficiency of overhead power lines. Short circuits are especially dangerous. The probability of occurrence of faults is reduced, but not reduced to zero, with an increase in the quality of installation, reliability, insulators and conductive materials. The proposed method is based on the fact that the short circuit current at the beginning of the transmission line of power electric system depends on the distance (location) to the fault point. This article discusses the following topics: theoretical possibility of fault location on the time of arrival of the responses to the beginning and end of the line, the development of the algorithm processing of information, the development of the block diagram of additional devices that are not included in the phasor measurement units (PMU). The article gives an example of the application of this technique.