变压器多特征励磁涌流识别方案研究

研究了变压器空投时，其等值电路模型参数在铁芯饱和后的变化情况，并通过分析不同情况下励磁涌流的特征，指出了传统励磁涌流判别方法的局限性。通过将传统方法优化组合，同时新加CT饱和识别判据，建立了一套多特征励磁涌流识别方案。通过对不同情况下励磁涌流的仿真分析，验证了所述方案的正确性。在高剩磁同时电压过零附近空充主变、低剩磁空充主变、无剩磁空充主变等环境下，所述方案均可通过多种识别方法配合正确地识别励磁涌流，可靠闭锁差动保护。在空投于故障变压器同时CT饱和时，所述方案也可根据CT饱和识别判据开放差动保护。

Research on multi feature recognition scheme of transformer inrush current

This paper studies the changes of the transformer equivalent circuit model parameters in the saturation of iron core when the transformer closes to power system without load, and by analyzing the characteristics of inrush current in different situations, points out the limitation of the traditional method to identify inrush current. By optimizing the combination of traditional methods and adding the new CT saturation recognition criteria, it establishes a set of multi characteristic inrush current identification scheme. By the simulation analysis of inrush current in different situations, it verifies the correctness of the scheme:such as closing transformer breaker in one side with high remanence and at the voltage near zero-cross, with low remanence, and without remanence, the scheme in this paper can correctly identify the inrush current by multiple methods cooperating with each other and reliably locking the differential protection; when closing to the fault transformer with CT saturation, the scheme can also unblock the differential protection with the CT saturation criterion.