基于一种新型磁场-电路耦合法的多绕组变压器复合短路阻抗及短路环流计算

多绕组变压器在不同短路工况下存在不同的短路阻抗,称为复合短路阻抗;不同短路工况下的各绕组电流均不相同.针对复合短路阻抗与短路环流存在的计算困难和计算时间长等问题,给出一种基于新型磁场-电路耦合方法的多绕组变压器复合短路阻抗及短路环流计算方法.在建立简化变压器磁场模型,得到绕组的电感矩阵后,将电感矩阵与外围电路结合,可以很快得到多绕组变压器复合短路阻抗与相应的短路环流.以某8绕组变压器为例验证,实测值表明该计算方法计算精度高,耗时较少,具有良好的工程应用价值.

Multi-winding Transformer Composite Short-circuit Impedance and Circulating Current Calculation Based on A New Field-circuit Coupling Method

The short-circuit impedances of multi-winding transformers vary in different short-circuit states, which are called composite short-circuit impedances. With different short-circuit states, the circulating currents of the windings are different. It takes a long time to solve the composite short-circuit impedance and the circulating current, and there are some difficulties in solving the formulas of the transformer. Aiming at the problems above, a new calculation based on a new field-circuit coupling method was provided. By building the simplified magnetic field model, the inductance matrix of all the transformer windings was obtained. The external circuit and the inductance matrix were combined, and the composite short-circuit impedances and the circulating currents of the multi-winding transformer can be obtained quickly. Taking a 8-winding transformer for instance, the measurement results show that this new calculation method is of high accuracy, low consuming time and high engineering value.