MV Fast Earthing Switch Technology Based On The Principle Of Electric Gun

As a new type of ultra high speed launching device,the electric gun has been widely used in military,aerospace,high pressure physics and high energy density physics and other research fields with excellent performance.The internal arcing fault of the MV switchgear will cause serious damage to the equipment and the personal safety.Therefore,reasonable measures should be taken to prevent it.According to the limitations of traditional actuator and its technical development trend and the requirement of arc fault protection of MV switchgear,the paper puts forward a new type of MV fast earthing switch(FES)technology based on the principle of electric gun with its structure design,parameter optimization,dynamic characteristics and the ability of fast arc extinguishing being deeply studied,the main contents are as follows:Firstly,the system architecture and working principle of a new type of MV arc extinguishing FES technology are described,which including the selection and shaping mechanism of the new electric gun actuator,the analysis of mechanism's reaction force characteristics,the influence of electric repulsion force on the switch,the theoretical estimation of permanent magnetic disk size and drive coil parameters.Secondly,using Maxwell to establish the axisymmetric two-dimensional finite element model of the electric gun operating mechanism.The influence of different factors on the dynamic characteristics of the electric gun operating mechanism is analyzed in detail by using the control variable method.Further,the paper proposes a multivariable optimization scheme based on the co-simulation of Matlab and Maxwell.It is realized by taking structural parameters of the electric gun operating mechanism as research object and taking the shortest time to complete travel distance as objective function.What's more,the integrated simulation and optimization of the parameters of the electric gun operating mechanism is realized by combining the intelligent optimization algorithm and the electromagnetic field simulation analysis.Thirdly,the dynamic characteristics test of the novel FES is completed through developing a dynamic characteristics test system of electric apparatus based on high-speed camera.Also,this thesis verifies the effectiveness and accuracy of the comprehensive optimization simulation of electric gun operating mechanism based on genetic algorithm optimization algorithm.Furthermore,the design of a real MV FES prototype and the analysis of the closing operations of this prototype are conducted in this thesis as well.Finally,building a low-voltage experimental platform to verify the feasibility of the proposed of the FES based on the MV FES prototype,arc generating device and a simple arc detection device,in the simulation test system of the medium voltage switch cabinet.It realized the accurate identification and rapid suppression of single phase to ground and phase-to-phase arc faults.The results show that the detection and rapid suppression of arcing faults can be simulated by the fast arc extinguishing technology of the FES in the expected time.The dissertation provides a new idea for the achievement of dynamic characteristics optimization by introducing the electric gun operating mechanism which is chiefly characterized by its compactness and fast-action to the switching device.A MV FES prototype is designed in this thesis,offering a practical structure for the new technical concept of FES.What's more,combined with the simple arc generating and the detection device,the study on the arc fault detection and fast suppression ability of the prototype is conducted in this thesis,which lays a technical foundation for the realization of the arc fault protection of the M V switch cabinet.