| At present, due to the centralized access of wind power and electric iron in some areas of our country, the frequent start of fault recorder equipment is caused, The situation of the wind turbine tripping off the network also happens occasionally, Power Grid Corp attaches great importance to this situation. Therefore, it is very necessary to carry out the study of the influence of the electric iron load on the regional power grid and wind farm, which can be used as a reference for regional power grid planning and construction. In this paper, the influence of electric railway on power grid and wind farm was studied based on the project, and the power quality control suggestions were put forward.First of all, in order to study the characteristics of the electric railway traction load, the traction power supply system model and the model of SS4 electric locomotive were established based on PSCAD/EMTDC simulation platform. These models can be used to simulate the acceleration/deceleration, heavy load/light load, different locomotive tracking intervals and so on.Secondly, this paper had carried out the power quality test of the district traction station.The measured data were analyzed based on DEWESoft software,the analysis results verify the correctness and feasibility of the model of SS4 electric locomotive.Aiming at the problem of negative sequence component in traction power supply system, a new type of negative sequence current detection method was presented. The novelty of this method was to make full use of the property of Hilbert function to replace the function of the phase locked loop in the traditional detection method. Therefore, the delay of the phase locked loop was reduced to the adverse effect of the results. By comparing with the traditional negative sequence current detection method, it was proved that the proposed method was more accurate and real-time.In order to study the power quality characteristics of the electric railway traction load, including the harmonic characteristics, the three-phase unbalance characteristics and the voltage fluctuation characteristics, the power quality data of SS4 locomotive under different operating conditions were obtained by simulation. The analysis of these data shows that the power quality characteristics of the electric railway traction load is closely related to the speed, position, load and the number of the traction network access.In order to study the influence of the electric railway traction load on the operation of the wind farm, this paper adopted the method of theoretical derivation and simulation analysis. Through the establishment of typical model of wind power generation system, the simulation of power grid and wind farm integration was realized. The simulation results show that the electric iron brings harmonic and negative sequence to the nearby wind farm. In addition, this paper also established the simulation model of the regional power grid. The simulation analysis was carried out by connecting the existing traction station model with the wind farm model to the regional power grid. The results show that the traction load of electric iron brings serious harmonic and three-phase unbalance to regional power grid and wind farm.Finally, based on the research results of this paper, we put forward the suggestion of power quality control for traction power station using three-phase SVC device. |
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