基于能量信息的变压器励磁涌流识别方法

目前电力变压器差动保护的主要问题仍是如何准确识别励磁涌流与内部故障。励磁涌流中包含大量谐波分量,各谐波分量除幅值、频率信息之外还包括能量信息。文中基于Prony算法给出了一种能量表达式,在此能量表达式下发现变压器内部故障时基波的能量与二次谐波能量之比远大于励磁涌流时基波能量与二次谐波能量之比,因此可以利用此特征区分励磁涌流和内部故障。最后仿真验证了该方法的有效性及与传统识别方法相比所具有的优势。

A Novel Identification Criterion for Inrush Current Based on Energy Information

The main problem for transformer protection is still how to identify inrush current. Inrush current contains a lot of harmonic components and some useful information is found in these harmonics, such as the magnitude, frequency and energy. The paper puts forward an expression for energy of a certain component based on Prony algorithm. It is found that the ratio of fundamental energy to second harmonic energy in the internal fault current is much larger than that in the inrush current. Thus a novel method is proposed to discriminate the inrush current from the internal fault current. Simulation results show that the method is effective and has better performance than the traditional methods.