高压电抗器匝间短路三维模型计算与分析

Calculation and analysis of three-dimensional model for turn-to-turn short circuit of high voltage reactor

为了研究干式空心电抗器匝间短路电流、磁场和电动力随匝间短路故障位置变化的分布规律,基于磁场-电路耦合电磁学理论,建立了外电路约束条件下干式空心电抗器匝间短路故障的三维磁场-电路计算模型。采用有限元法计算正常状态下该模型的电感与各层电流,将计算结果与解析法所得结果、实测数据进行对比,验证了该模型的准确性。建立匝间短路故障模型,精确计算匝间短路电流。研究结果表明:当电抗器发生匝间短路故障时,短路电流较正常电流急剧增加,不同位置的匝间短路故障的短路电流呈现出端部向中心位置、内层向外层增大的趋势;匝间短路故障处的磁场与电动力迅速增大,短路层的磁场与电动力方向发生改变。

In order to study the distribution law of turn-to-turn short circuit current,magnetic field and electrodynamic force varying with the change of turn-to-turn short circuit fault position for dry-type air-core reactor,a three-dimensional magnetic-field-electric calculation model of turn-to-turn short circuit of dry-type air-core reactor under external circuit constraints is built based on the field-circuit coupling electromagnetism theory.The inductance and the current of each layer of the model in normal state are calculated by the finite element method.The calculated results are compared with the results gained by the analytical method and measured data to verify the accuracy of the model.The model of turn-to-turn short circuit fault is built to accurately calculate the turn-to-turn short circuit current.The study results show that when turn-to-turn short circuit fault of reactor occurs,the short circuit current sharply increases compared to the normal current;the short circuit current of turn-to-turn short circuit fault in different positions tends to increase from the end to the center and from the inner layer to the outer layer;the magnetic field and electrodynamic force in the position of turn-to-turn short circuit fault increase rapidly,and the directions of magnetic field and electrodynamic force in the short circuit layer changes.