Research On Reactive Power Compensation Of SVG In Distribution Network

In recent years,with the rapid development of distributed new energy technology and the strong support of national policy,distributed new energy is more and more common to integrate to grid with its advantages such as little pollution to the environment,investment scale is small,flexible power,lower operating costs.The continuing increase of large-scale distributed new energy to grid leads to a significant complexity of grid structure,and the increasing nonlinear load and impact load cause the variation of power quality,mainly in the rapid change of reactive power,harmonic current and so on.In dealing with the problem of reactive power,the disadvantages of traditional compensation device such as slow response speed,large volume,large harmonic and loss and a lot of material,easy oscillation faults make it difficult to develop further.However,the application of Static Var Generator it has the advantages of quick response,smooth reactive power regulation,strong ability to adjust reactive power under low voltage and the condition of reactive power,also have the function of harmonic suppression,voltage regulation,etc.This article is based on the working principle,advantages and disadvantages of Static Var Generator(SVG)with all kinds of topology structure in low voltage power grid,and the proper topology is selected,then the controller based on predictive current control is designed.The contents of this paper include:1 The background and the meaning of this study are introduced,and the problem of reactive power and harmonic current is also analyzed,then the effect and meaning of reactive power compensation are summarized,In order to deal with this problem,the development and application of traditional compensation devices are introduced.Then the application background,developing direction and application situation in and out of country of Static Var Generator are summarized.All the above prove the necessity of the study of SVG.2 The working principle and characteristic of Static Var Generator(SVG)are deeply analyzed.Then the advantage and disadvantage,applications of several different topologies of SVG are introduced.Considering the performance and economic factors of several topologies,the topology with three levels and four legs is selected as the main structure of SVG in this paper.3 Aiming at the control strategy of SVG,the composition of the control strategy used in this paper is given in detail,and the working principle and design of reactive current detection and dc voltage control are analyzed.On the basis of introducing several current tracking control methods,the hysteresis comparison method in direct current control is selected as the main method in this paper and its working principle is analyzed.The detailed analysis of the parts of the control strategy for provides a theoretical basis for simulation next.4 The simulation module is designed in MATLAB and the simulation results show that the introduced method has better validity.