Research On Mixed Compensation Of SVG And SVC Based On Multi-communication Mode

In recent years,with the rapid increase of high-power nonlinear power electronic equipment,a large number of harmonics and reactive power rush into the power grid,seriously affecting the power quality,resulting in reduced system power factors,voltage fluctuations,system efficiency reduction and other problems.The reactive power compensation device occupies an indispensable position in the power distribution system.Therefore,optimizing and improving the reactive power compensation technology has important theoretical research and engineering significance to reduce the burden and improve the operation efficiency of power grid.The main contents of this thesis are as follows:Firstly,in order to solve the problem of reactive power compensation more cost-effectively,the reactive power compensation device used in the current power grid is discussed in detail.Based on the comparison and analysis of SVC(Static Var Compensator)and SVG(Static Var Generator),this thesis presents a hybrid compensation technology combining SVC which is based on bus and wireless communication technology with SVG which is based on current direct control.Secondly,on the basis of detailed analysis of the traditional compound switch technology scheme,this thesis studies the principle,structure and communication mode of the compound switch,improves and optimizes the traditional level control mode.This thesis proposes a technical solution using bus communication control mode and wireless communication control mode.In this thesis,a new type of reactive power compensation switch is designed,which is an integration of level control,bus RS485 communication control,and wireless control based on wireless module NRF24L01.Through the construction and experiment of the actual software and hardware circuit platform,it is proved that this device can communicate through the bus and wireless technology,and can be applied to the capacitor zero voltage input and the current zero-cut.Compared with the traditional composite switch,this program has the advantages of modular,miniaturization and less wiring.Thirdly,this thesis studies and discusses SVG compensation methods,and uses MATLAB / Simulink to build and simulate the model.The reactive power circuit detection method is based on the instantaneous reactive power theory,and the direct current control is used in control strategy.Through a comparison of the phase voltage and current waveform before and after the compensation,the program is verified to be accurate and effective.Finally,the task assignment in hybrid compensation is analyzed in detail,and the technical scheme is put forward.The experimental results show this is an ideal compensation method,which not only has good dynamic characteristics and wide operating range of SVG,but also the effective capacity of SVC to compensate the capacitive reactive power with low cost.The experimental and simulation results show that in the case of switching the fixed capacitor bank,the composite switch designed in this thesis meets the requirement of frequent switching capacity and can realize zero-crossing switching without generating inrush current.In the case of dynamic compensation,after the input of SVG reactive power compensation device,the power factor of the system is obviously improved,which proves the effectiveness of the reactive power compensation scheme.