Modes, Parameters and Efficiency of the Functioning of Electric Supply Systems of Underground Mine

Abstract

The paper considers the issue of increasing the efficiency of electricity use in iron ore mines. The process of underground mines’ electricity consumption is considered probabilistic. To increase the accuracy and reliability of the assessment of the state of the process of electricity consumption, its description requires the use of methods that allow you to make decisions in the current conditions of uncertainty and incompleteness of information. Practice shows that the actual load is very different from the calculated; therefore, there is a need to clarify the method of determining loads. Technologies have changed today and the working conditions have changed, that is, it is necessary to determine new demand ratios for individual groups of consumers, which is practically impossible, because at the enterprise all groups of consumers work from the same network, that is, the method of the demand factor does not correspond to the current structure of electricity supply. Improvement of the method of demand factor was carried out by introducing empirical coefficients into it.

A new generalized method for calculating the technological groups of consumers is proposed, which differs from the known ones by the absence of an artificial separation of them according to the operating modes corresponding to the real structure of power supply systems for mining and a number of other industrial enterprises. The proposed calculation method can be used with the help of conventional metering devices that are in the network or determine the coefficients in the reference literature. The calculation procedure for electrical loads is universal and acceptable for any production and power supply systems.

According to the results of comparative calculations, the calculated power, obtained by the generalized method, is 30...40 % less than other applied methods and is much closer to the actual values, and the loading of power transformers of mine district substations is only about 30 %. It is estimated that the total transformer power at underground substations of mines can be reduced by 1,5—2 times. The analysis of the obtained results on the example of the real power supply scheme of the mine shows a discrepancy in the direction of overestimation of 50...70 % of the installed capacities of the transformers of the substation.

The prospects of increase of indicators of power supply in mines networks are determined. The main reason for the overestimated losses of electric energy in the power supply systems of mines is the imperfection of structures and their parameters, which is laid down at the design stage, and is associated with the use of a determinant criterion focused on saving investments, and not on energy efficiency.