Electromagnetism Analysis And Design Of Magnetic Shielding Of Transient High Intensity Magnetic Field Based On The Air-core Reactor Of EAST

EAST(Experimental of Advanced Superconducting Tokamak)is a fully super-conducting Tokamak equipment which designed and developed by China.Its objective is to solve the problems of the plasma near core steady state advanced operation mode.Fast control power supply system is one of the most important constituent part of EAST power system.Its action is providing thousands ampere excitation current for the internal vacuum coils to maintain the operation of plasma by detecting the movement of plasma.In practical engineering,the parallel output mode is used to satisfy the demand of response and high drive power.However,the powerful excitation current cause serious of electromagnetic problems.The output cabinet of sharing reactor have overheated and electromagnetic interference by passing the powerful current.Therefore,it is necessary to take measures to shield the low frequency non-sinusoidal magnetic field interference.In this paper,based on the output cabinet of sharing air-core reactor of EAST fast control power supply system,this thesis makes study of electromagnetic analysis and design of magnetic shielding.The eddy-current loss,shielding effectiveness and changing of inductance are analyzed in low frequency non-sinusoidal magnetic field.Three kinds of magnetic shielding are proposed and electromagnetic problem are analyzed.The best shielding method is chosen which based on the above analysis.By experiment,the multilayer combination magnetic shielding method is optimized.The suitable engineering material type and thickness are selected.In this paper,the scientific research achievements are as follows:1)Based on the FEM(Finite Element Modeling)of output cabinet of air-core reactor,the calculation model of the output cabinet of the air core reactor is established and the magnetic field intensity of the corresponding observation point is calculated;2)By the analysis of the eddy current loss of the sinusoidal transient magnetic field,the method of calculating the eddy current loss in non-sinusoidal transient magnetic field is proposed;3)Based on the principle of magnetic shielding,a comprehensive analysis of the electromagnetic shielding problems of three kinds of the eddy current loss,shielding effectiveness,inductance effect,shielding selected multilayer composite type cabinet shielding at low frequency transient non sinusoidal magnetic field.The eddy current loss and shielding effectiveness of multilayer cabinet are verified by experiments;4)To practical engineering problems,such as the proposed long gap,cabinet opening and shielding door,and ventilation mode of the cabinet,are optimized to provide effective suggestions for the subsequent design of the cabinet.In this paper,a series analyzing of the output cabinet of air-core reactor of EAST power supply system is analyzed.A useful magnetic shielding method is designed to boycott the low frequency non sinusoidal magnetic field.And the overall architecture of shielding cabinet is designed.It has certain practical value for solving the problem of the existing cabinet.