Calculation Of Winding Wave Process And Development Of Simulation Software In Extra-High Voltage Power Transformer

After summarizing relevant literatures, lightning shock wave process in extra-high voltage transformer winding and the capacitance and inductance parameters calculation problems are studied deeply in the thesis. A few achievements with values on theory and engineering have been gained and a software package practical in engineering is developed. Referential rules are provided to improve longitudinal insulation intensity of transformer winding.The significance and purpose of the calculation of power transformer winding wave process are introduced in the beginning of the paper, and then the development of transformer winding equivalent circuit and winding parameters are discussed. In the part of the calculation of transformer winding capacitance parameters, both empirical formulas and finite element method are adopted in the paper. The non-uniform electric field which influence capacitance parameter is considered, and the turn-to-turn capacitance and the earth capacitance are calculated between the winding disks. The equivalent capacitances between the winding disks are gotten by the equivalent circuit in the Simulink, and fixed the empirical formula solving value. In the calculation of wave process, the calculation formula is deduced according to the single winding wave process calculation of the equivalent circuit. The method is suitable for the application of Matlab language to solving. The initial distribution, node potential waveforms, potential maximum and the oil gradient distribution are calculated.Taking ODFPS-1000000/1000 type and SFP-400000/500 type power transformers for example, the initial distribution, node potential waveforms, potential maximum and the oil gradient distribution are calculated. The calculated and experimental data are compared for the SFP-400000/500 type power transformer and the error is within permitted, and then analyzes the reason which lead to the calculation error appears. So it proves that wave process software calculated data validity. The result indicated that their winding longitudinal insulation intensity satisfies the request.Based on above studies, a software package is developed which can be used to analyze lightning shock wave process for transformer of various voltage classes, capabilities and kinds of structures under operation and fault conditions. The software package is based on windows platform and has good pre and post processing function.