Study On Electric Field Calculation Of Static And High Frequency In High-Voltage Electrical Equipment

With the increased voltage transmission lines, the system capacity improved, so a higher insulation requirements is proposed for the high-voltage electrical equipment. Good insulation equipment directly affects the overall operation and power system security and stability. In the paper, three-dimensional electric field of ultra-high voltage casing and disconnector is calculated and analyzed, to understand the electric field distribution inside the device, and provide the necessary parameters for designing the insulated structure. In addition, hige frequency electric field of the transformer casing is calculated on VFTO, to provide the references for designing insulation of equipment.First, based on electromagnetic field theory, three-dimensional finite element analysis model of ultra-high voltage casing is established. For the structure characteristics of the product, combining smart division and local refinement method to receive the reasonable solution. By analyzing the eletric field distribution inside the casing, the position and the value of maximum field is obtained, even to provide the theoretical references for the insulatec structure of the casing.Second, based on the theory of domain decomposition,3D gas chamber model in UHV disconnector is established, and the result is compared with that of overall approach. The results show that, RAM limit is effectively relieved by domain decomposition, that improve the solution efficiency, and even solve the large amount of computation and storage, low efficiency when lager-scale electromagnetic field calculation by FEM. Also, based on the approach of electric field energy, the capacitance of the gas chamber in disconnector is calculated by APDL, and the error of the calculate value and the test value is less than 4 persents. The accurate capacitance lays the fundation for the reseach of VFTO. Finally, combined a 1100kV substation in the country, VFTO is calculated on thansformer during the disconnector closing by EMTP, and make spectrum analysis to the voltage waveform with MATLAB. Taking nolinear media and different frequency components of the waveform into account, Mathmatical model of the casing end is established in high frequency eletric field,and its eletiec field distribution is received, in additon, compare the result with that of static eletirc field, then provide reasonable theoreture parameters for designing the insulated struction.