Calculation And Analysis Of Physical Fields In High Voltage Power Capacitor

Power capacitor acts as a role of reactive power compensation and filtering in highvoltage power transmission. Once one capacitor is damaged, the whole unit even theentire system would fail to work. The breakdown parts of power capacitorcomponent are generally occurred in the region where the electric field intensity isconcentrated. The crack at the casing tail will result in the damage of main body, andburst into flames. A power outage will be caused, so the economic losses will bevery great. The operating temperature of power capacitor affects the service life ofthe capacitor directly. So the accurate computing of component electric field, casingelectric field and temperature field in capacitors is of great significance to the designand operation of capacitors.Firstly, according to the inner structure of power capacitor component, the2D and3D finite element method(FEM) calculation model of inner electric field areestablished, and the electric field distribution characteristics are obtained. Thefactors that affect the electric field, such as, the medium material, electrode thicknessand medium thickness are researched. Specially, the electric field distribution atcomponent edge is given, and the relationship between voltage and mediumbreakdown field intensity is discussed. The solutions to reduce the maximum electricfield intensity are come up with.Secondly, According to the axial symmetry structure of high voltage casing, a2Dcalculation model of power capacitor casing is established, and the finite elementsoftware is utilized for the numerical calculation of casing electric field. The electricfield distribution characteristics of power capacitor casing are obtained.Finally, the capacitor fever produced by internal dielectric loss is considered. The3D finite volume method(FVM) calculation model of capacitor temperature isestablished, and the temperature distribution characteristics and the internaltemperature at the hottest spot of capacitor are obtained. With the research on acorresponding prototype, the numerical simulation results are consistent with the tested values, and the accuracy of temperature calculation model is testified.