Research On EMI Filtering And Shielding Technology In Power System Secondary Equipments

The Electromagnetic Compatibility was the threat posed to the reliability of secondary equipments in power system. Filtering and shielding technology were studied in this paper. The basic principles about filtering and shielding were analyzed first. We draw the curve of insertion loss based on the circuit system builded with PSpice. The filtering performances in different source-load impedance matching were analyzed by the curve. With the same method, the high frequency circuit model was builded, and the impact of scattering parameter on insertion loss was analyzed. Also, shielding effect of shielding structure were studied by EM simulation software based on FEM. Especially the shape and arrange of holes were discussed. Finally, a method of shielding effectiveness testing on small metal box was proposed, and it proved feasible thorough comparison between testing data and calculation data.