The Comprehensive Evaluation Of Coal Mine Power Quality

Coal mine power quality is an important issue related to the survival and development of coal mine enterprises. With the rapid development of coal enterprises, a sharp increase in the production of coal mine electric power load and the increase size of the power supply system, a large number of non-linear power load has been used, especially large variable frequency speed regulating device, rectifier converter device are accessed in power grid, which made the power quality such as harmonic, voltage sag, voltage distortion and power factor is low and other issues become increasingly prominent.According to the particularity of coal mine power grid, we analysis of electric equipment of power quality characteristics of the nonlinear circuit in the power system of coal mine power grid, clear main power quality problems may exist in the electrical regions, which provides a theoretical basis for the establishment of comprehensive evaluation index system of quality.According to the analysis of system of nonlinear load in coal mine power grid, a set of complete coal mine power quality evaluation index system for the description of the operation characteristics is established. It include three primary indicators: voltage, current, power factor index and eighteen secondary indicators. Among them, the total current harmonic distortion based on the maximum demand load current, as well as the displacement power factor and distortion power factor objective definition of non power factor sinusoidal circuit, making the index system is more suitable for the situation of coal mine power grid.Based on the coal mine electrical parameter is tested by power quality tester, we get detailed operational data of coal mine power grid, calculate the power quality index value by professional power quality analysis software. Focus on the uncertainty of synthetic evaluation of power quality, the set pair analysis method is introduced, the evaluation index and evaluation standard are formed a set pair, we establish a power quality comprehensive evaluation model, and combine determination of the subjective with objective combination weighting in order relation method and variation coefficient method, which made the evaluation results more reasonable.Through the comprehensive evaluation of coal mine power quality, we can not only find the interference sources which affect the power quality of power grid in coal mine and take targeted measures, but also can quantitatively show the overall operation of the level of coal mine power quality.