Break Arc Experiment And Simulation Study Of High Voltage DC Contactor

With the development of the electric vehicles,rail transit,aerospace,photovoltaic power generation,DC ecological housing,modern ship power supply system and low voltage DC distribution network,as a key component,DC contactors will be more widely used in the breaking,protection and control of electrical equipment and transmission and distribution networks.However,Due to the arc erosion caused by the DC contactor during the breaking process,the electrical life of the contactor is not high,which is far from the mechanical life.In this paper,the high-voltage DC contactor is used as the research object to study the effects of arc-extinguishing magnetic field,arc-extinguishing grid,contact structure and other factors on arc-extinguishing effect and contact life.Through the comparison of experimental and simulation results,the factor is obtained for arcing.The mechanism of time influence is used to guide the design of high-power DC contactors,thereby improving product life.Magnetic blowing is one of the effective ways to quickly extinguish the breaking arc of high-voltage sealed DC contactor.The strength of magnetic blowing magnetic field has an important influence on arc extinction.Therefore,this paper first studies the effect of magnetic field strength on the arc combustion process.The arc simulation model is established under the condition of polar arcing magnetic field.The voltage variation law of the two ends of the contact in the process of breaking under different magnetic fields is obtained by simulation,and then the relationship between the magnetic field and the arcing time is obtained.In order to avoid the complicated wiring of the contactor,design a non-polar arc extinguishing chamber,and the arc breaking experiment is carried out.The advantages and disadvantages of the polar and non-polar arc extinguishing chamber are analyzed through comparison of experimental results.Different contact structures have an important influence on the breaking current level of high-voltage DC contactors.Therefore,this paper carries out the traditional bridge double-break contact structure,the new parallel double-break contact structure and the new series four-break contact structure.Experimental study on DC resistance load breaking arc.Through the breaking arc experiment under different arcing magnetic field conditions,the arc changing process during the breaking current of three contact structure contacts is obtained,the arc changing mechanism is analyzed,and the advantages and disadvantages of the three contact structures are compared,which is beneficial to different conditions.The arc-extinguishing contact structure provides a theoretical basis for the design of the contact structure.According to the comparative analysis results of the three contact structures,a contact structure is selected,which is matched with the arc extinguishing chamber of the arc-splitters.The influence of the arc-splitters on the arc is studied.The arcextinguishing effect of the arc chamber with the arc-splitters is studied by the test bench.The arc-extinguishing mechanism of the arc-splitters is analyzed,and different parameters(arc-splitters length,number of arc-splitters)are studied.The relationship between the arc-splitters and the arcing time is obtained,and according to the actual application,the arc-extinguishing chamber with the arc-splitters is designed to further reduce the arc burning time and prolong the service life of the DC contactor.