Research And Realization Of Control System Of DC Micro-grid Hybrid Circuit Breaker

With the development of renewable and distributed new energy,the technology and equipment of DC power transmission system are one of the focuses in the field of electric energy protection research at home and abroad.Because the DC power system has the advantages of small line loss and good reliability of the synchronous operation of the power grid system compared with the AC grid,the development of the DC circuit breaker used in the DC system has always been the focus of the study.However,the DC fault current is facing the following problems: no natural zero-crossing,arc quenching difficult.Therefore,it is the goal of this paper to design a DC micro-network hybrid circuit breaker which can quickly cut off the fault current and ensure the stable and reliable operation of the system.This paper compares several types of DC circuit breakers that have been widely used today,and compares their topology,breaking principle,operational stability and project feasibility respectively.In the DC micro-network system,by the mechanical switch with the power electronic components IGBT composed of mixed DC circuit breaker,can better break the fault current.The system designed in this paper has the advantages of fast breaking speed,equipment loss,switch life and running stability.In this paper,Matlab simulation platform is used to set the corresponding simulation parameters for the arc model of the system,IGBT circuit of electric power electronic components,RCD circuit and zinc oxide arrester.To meet the design principles of the model to verify the development of DC hybrid circuit breaker ideas to achieve the fault current transfer and absorption.According to the principle of hybrid circuit breaker system,the vacuum switch connected in parallel with the power electronic component.The control system chooses the STM32 micro controller to complete the hardware and software structure design of the control system.The relevant parameters of the circuit breaker of the circuit breaker are selected and the design idea is verified by the short circuit fault breaking test.In the 400 V,200A DC micro-grid test platform designed in this paper,the prototype completes the requirement of fast breaking fault current.Power electronic components IGBT circuit effect is obvious,through the control system current detection,to complete the fault current from the circuit breaker to the IGBT circuit movement,reducing the loss of the vacuum switch.RCD buffer absorption circuit and arrester absorption protection circuit can be effectively absorbed dissipate the excess energy in the system,when a fault current is cut off,to avoid damage to the DC circuit breaker apparatus overvoltage.