基于漏感抗在线识别的变压器绕组变形监测技术的研究

基于短路阻抗法原理研究了对绕组变形的在线监测技术和实验室研究平台。提出了一种快速计算变压器绕组漏电抗的计算方法:在电流峰值处,直接由电压差和电流比值得到漏电阻;在电流过零处,直接由电压差和电流微分的比值得到漏电感;对一、二次电压先在硬件电路中先进行减法放大到采集卡的输入极值附近,再采集,将算法的分辨率几近提高到采集卡的最大精度。研制的监测系统,在实验室绕组变形研究平台上进行试验研究并初步提出变形判据,并在现场得到应用。研究结果表明,这为现场变压器在线监测绕组故障提供了一种有效的方法。

On-line Monitoring of Transformer Winding Deformation Based on Identification of Leakage Inductance

An on-line monitoring technology of transformer winding deformation and corresponding experimental platform were presented according to the theory of short-circuit impedance analysis.Consequently,a method for rapidly computing the leakage reactance from transformer winding was proposed.The leakage resistance is obtained from the ratio of voltage difference to current at the peak of current,and the leakage inductance is also obtained from the ratio of voltage difference to differential of current when current is zero.The voltage difference of primary and secondary winding is magnified near the input limit of AD acquisition card with hardware before sampled,thus the resolution of the algorithm is increased to the maximum precision of the card.The present on-line monitoring system was tested on the experimental platform,and a criterion was also proposed for judging the state of winding.The test and practical application results verify the effectiveness of the present on-line monitoring system.