Under the conditions of rising prices for electric power, the improvement of consumption modes acquires special importance. Analysis of the use of technical means showed that group voltage regulation in networks of mining enterprises is carried out mainly with the help of mechanical devices for voltage regulation under load (AVR) - power transformers with capacity above 1 MV-A. Among many ways to improve modes of consumption a special place belongs to voltage mode regulation, as it allows to reduce power component for 10-15%, to maintain stability of electrical equipment operation and increase its service life. The article reviews the design of on-load tap changers, shows the methodology of selecting the settings of on-load tap changer operation for enterprises, where there are electric consumers, power supply of which is carried out by long lines, as well as electric consumers working in heavy load conditions (coal and shale mines, coal and ore pits, etc.). The calculation methodology is given, which allows to determine the economic effect obtained by introduction of the on-load tap-changer and the target function of economic efficiency of regulation is built, clearly demonstrating the advantages of application of such devices.
