变压器匝间短路建模及其实际应用

针对变压器匝间短路问题,提出将短路绕组等效成两个不同绕组的思路,并以三绕组变压器低压侧匝间短路为例进行建模,首先把发生短路的三绕组变压器等效为四绕组变压器,然后推导变压器的中低压侧电压公式。根据公式不仅可以计算短路信息,还证明了中低压侧电压都有明显降低,且低压绕组电压降低更严重。利用建立的模型,对广西电网某220 kV变压器匝间短路事故进行Matlab仿真分析,仿真曲线及短路匝数判断与实际录波波形及检查结果吻合,验证了模型的正确性。

Transformer inter-turn short circuit modeling and its application

Aiming at transformer inter-turn short problem, this paper presents an idea which is equivalent the shorted winding to two different windings. The modeling of equivalence is proposed with the low voltage side inter-turn short of three windings as an example. First, the shorted three-winding transformer is equivalent to a four-winding transformer. Then a formula in the middle and low voltage sides is derived, according to which shorted information is calculated and the decrease of middle and low voltage sides is deduced and the latter decreases more seriously. The model is applied successfully to the simulation and analysis of the Guangxi power grid 220 kV transformer inter-turn short circuit by MATLAB, the simulation curve and result of analysis are coincide with examination results and recorded curve, which verify the correctness of the model.