Research On Reactive Current Detection And Control Strategy For Static Var Generator

With the continuous development of social science,technology and electronic devices,there is no longer only pure resistive load in the power grid,and more and more non-pure resistive loads have seriously affected the normal operation of the system,so the reactive power compensation of the power system has become extremely important.Compared with the traditional compensation device,the static var generator has the advantages of fast compensation speed,smooth compensation,safe and reliable operation,etc.Therefore,the static var generator has replaced the traditional compensation device and becomes the mainstream research direction in the reactive power compensation device.This paper focuses on the research of static var generators.This paper first introduces the development process of reactive power compensation device,and selects the static reactive power generator after comparing the advantages and disadvantages of each stage device.Then the main topology diagram of static var generator is introduced.The working principle of voltage bridge circuit is introduced in detail and mathematical modeling is carried out in abc three-phase stationary coordinate system.In the aspect of reactive current detection,after introducing and summarizing the PQ operation mode and ip-iq operation mode,a detection method based on the combination of instantaneous symmetrical component method and ip-iq operation method is proposed to be applied to the three-phase unbalanced system.in.In this paper,the double closed-loop current direct control strategy of current inner loop and voltage outer loop is adopted,which achieves the effects of three-phase balance,three-phase unbalanced compensation and harmonic suppression.Finally,based on the above theoretical analysis,the simulation model of the static var generator is established by MATLAB/Simulink,and the conditions of the asymmetric load and the asymmetric power supply in the three-phase unbalance are simulated under different load conditions in the three-phase balance.Verification,simulation results show that the SVG device under the control strategy has a good reactive power compensation device.