变压器励磁涌流的FFT和小波分析

Inrush Current Analysis Based on FFT and Wavelet

从工程应用的现状来看,世界上大多数国家都将纵联差动保护作为变压器主保护。变压器的差动保护,一方面需要面对主设备保护共同的TA保护问题,另外一方面还需要面对变压器特有的励磁涌流问题。要保证差动保护的选择性与灵敏性,就必须躲过变压器外部故障时的最大不平衡电流,同时正确的识别空载合闸励磁涌流和内部短路故障电流。本文利用FFT和小波分析,对变压器励磁涌流产生机理及特征分析进行了研究。并利用MATLAB软件的SIMULINK/PSB工具箱对变压器模型在空载合闸状态进行仿真,并利用POWERGUI/FFT analysis和小波分析GUI工具箱对涌流波形进行分解,获取变压器保护中辨识励磁涌流的有利信息。

From the view of engineering, most countries in the world use differential protection as main protection of transformer. On the one hand, transformer differential protection needs to face the common TA protection of the main equipment also have to face on the other hand, the transformer inrush current problem. In order to ensure the selective and sensitive, it is necessary to avoid the failure of the transformer of the largest external imbalances in current, at the same time switch on the correct identification of no-load inrush current and internal short circuit fault current. In this paper, mechanism and characteristics of the transformer inrush current are researched based on FFT and wavelet analysis. The transformer model which is closed in the state of no-load is simulated using of MATLAB software SIMULINK/PSB toolbox. Inrush current is decomposed with POWERGUI/FFT analysis and wavelet analysis GUI toolbox, and gains the useful information to solve the problem of transformer inrush current.