Research On Power Quality Evaluation And Governance Of Typical Random Loads Connected To Power Grid

The power quality problem caused by random loads connected to the power grid has always been the focus of attention for both power providers and consumers.In-depth understanding of the power quality characteristics of random loads and the evaluation of power quality connected to the grid can provide a basis for power companies to manage the load and formulate corresponding governance measures.In this paper,the electric arc furnace is selected as the representative of the random load for research.The common electric arc furnace model is improved.Through the evaluation process designed in this paper,the power quality evaluation of a nickel-making plant in Shandong is carried out,and a new hybrid The topological structure of the source filter is used to manage the power quality problems that occur.The specific research contents are as follows:This article describes the development status of power quality research and evaluation at home and abroad,and introduces the concepts of power quality related indicators such as harmonics,voltage flash,and three-phase unbalance.According to the relevant standards for power quality issued by my country,the three-level power quality assessment system for traditional power users to access the power grid has been improved.Afterwards,the research of this paper is carried out for the specific problems of power quality.Aiming at the fact that the traditional electric arc furnace model cannot truly reflect the power quality problems of different smelting stages of the electric arc furnace,a dynamic electric arc furnace model was established by adding characteristic signals to the steady state model of the electric arc furnace.The comparison of the dynamic impedance characteristics of the electric arc furnace shown in the simulation experiments with typical wave forms proves that the dynamic model of the electric arc furnace applicable to different smelting stages is effective.Aiming at the shortcomings of traditional hybrid active filters that cannot be applied in high voltage environments,this paper analyzes the advantages and disadvantages of traditional active and passive filters,and proposes a hybrid series active filter topology based on the instantaneous reactive power theory.Compared with the traditional hybrid active filter,the hybrid active filter proposed in this paper has a strong performance in the harmonic injection capability and the withstand voltage of the active part,so that the filter can work in a high voltage environment.In addition,according to Fourier analysis,the filter proposed in this paper can provide large-capacity reactive power compensation in addition to its superior filtering performance under high-voltage environment.