In this paper an actual problem – the controlling of voltage regime in distributed circuit of mineral raw industry with the help of for power transformers. Particular attention spare for in- vention of automatic controlling block for equipment of voltage control under the power using theory of fuzzy logic. There are the results of mathematics and computer modeling.
Ensuring of rational voltage mode by means of automatic change of power transformer under load (OLTC) transformation coefficient under conditions of load parameters variation and configuration of supplying lines is considered. The technique of a choice of a determining voltage mode of connection in power supply system of enterprises on extraction, transportation and processing of mineral resources with application of methods of the theory of fuzzy sets is offered. Parameters are used, which allow describing the state of distribution lines and electric consumers, dispersion of load along them, damage at a voltage deviation from a rational level in real time. The structure of control system based on fuzzy logic is given. The graphs of the membership functions of five parameters, the totality of which determines the power supply line mode, are given.
At present, about 20% of all produced energy is spent on mining, transportation and processing of minerals, and the energy component in the total production costs reaches 30-60%. Therefore, under the conditions of rising electricity prices and energy resources saving, the issue of reducing the energy component in the total cost of production and processing of minerals and reducing electricity losses acquires special significance. The voltages of individual electrical consumers must be such that their reliable, economical and stable operation in the whole possible range of technological and electrical parameters is ensured. Voltage regulation at the end of a section at a given load can be performed by changing: the voltage at the beginning of the section; the transformation ratio of the transformer included at the beginning of the section; the inductive resistance of the section, for example by including a longitudinal compensation unit; the active resistance of the section; the reactive power flow in the section. It was found that the application of measures to stabilize the voltage provides an increase in service life of electrical equipment of mine sections on average by 10-15%, the main transport and conveyor elevation - by 7-12%. To increase voltage stability, it is reasonable to form the structure of district networks taking into account the occurrence of minimum deviations of the network voltage relative to the rational level.
