基于非饱和区等效瞬时电感波形特征的变压器励磁涌流鉴别方法

分析变压器各种情况下等效瞬时电感的波形特点,提出一种利用波形波动函数检验变压器是否发生励磁涌流的新方法。该方法根据等效瞬时电感在非饱和区域波形变化剧烈的特点,通过计算波形的波动系数来识别涌流与故障电流。动模实验结果显示,即使对于匝间轻微故障,该方法也具有比较高的灵敏度。此外,该方法无需利用变压器的任何参数,仅需测量三相差流和原边各相相电压,算法计算量小,实现简单,整定容易。

Identification of Transformer Magnetizing Inrush Based on Waveform Characteristics of Equivalent Instantaneous Inductance in Non-saturation Zone

A new waveform fluctua-tion function algorithm to distinguish the inrush and fault current of power transformer is put forward based on the waveform differences of equivalent instantaneous inductance. The algorithm can identify inrush and fault current by calculating the waveform coefficient according to the characteristics of equivalent instantaneous inductance rapidly chang-ing in non-saturation zone. The experimental results indicate that the proposed method is reliable and sensitive even to low level of turn-turn faults. In ad-dition, the method just need to measure the three-phase difference currents and primary voltages without adopting any parameters of the transformer, and thus with little calculation, simple and easy to set up.