Research On Effects Of High Energy Consumption Load On Power Quality Of Power Grid

In recent years, a large number of high energy projects have been launched in some areas of Ningxia, such as electrolytic aluminum, calcium carbide, iron alloy, cement, etc. High energy consumption loads are nonlinear and unbalanced load, these large capacity high energy consumption loads access to the regional power grid, which result in power supply voltage deviation, frequency deviation, harmonics, voltage three-phase unbalance, voltage fluctuation and flicker and other power quality index variation. In the future for a long period, high energy consumption loads in the area must further develop. Therefore, it is urgent to systematically study the power quality problems of high energy consumption load in this area.In this thesis, according to the access conditions of high energy consumption load in this area, the three kinds of typical high energy consuming loads, such as arc furnace, electric railway traction and electrolytic aluminum, have been selected as the research objects. The effects of these three kinds of high energy consumption load on the power quality of the power system harmonics, three-phase voltage unbalance, voltage fluctuation and flicker power quality index are studied, and the relevant indicators of national standards are compared and analyzed. Then the main power quality problems of different types of high energy consumption load are obtained, and the management measures are put forward.Firstly, a comprehensive model of three-phase electric arc furnace is built-in PSCAD simulation platform based on the physical characteristics of arc and the law energy conservation. The load characteristics of electric arc furnace are analyzed by simulation. The basic structure of the HXD3 AC-DC-AC drive electric locomotive is also studied. In the PSCAD/EMTDC simulation platform, the simulation model of HXD3 locomotive is built, and the load characteristics of symmetrical and asymmetrical two conditions of electric railway traction load are analyzed. In the PSCAD simulation platform, the model of electrolytic aluminum rectifier load is established, and the load characteristics of electrolytic aluminum rectifier are analyzed by simulation.Secondly, based on the actual data measured in the regional power grid, the effects of electric arc furnace load, electric railway traction load and electrolytic aluminum load on the power grid are analyzed from three power quality indexes, such as harmonics, voltage fluctuation, flicker and three-phase voltage unbalance. It is concluded that the main power quality problems of high energy consumption load are connected with the power grid in the area.Finally, based on the above analysis, the corresponding power quality control measures are proposed for the three kinds of high energy consumption load. For the electric arc furnace load, the control measures of SVC and passive filter are adopted, the control measures of SVC and passive filter are adopted for the electric railway traction load, and the control measures of the passive filter are adopted for the electrolytic aluminum load.