基于振动的变压器绕组松动缺陷诊断方法

将理论与实验相结合，对变压器绕组松动缺陷诊断方法进行研究。理论上定义了基于预紧力的变压器绕组松动缺陷特征值，该特征值与变压器绕组预紧力之间存在规律的单调区间，提出利用该关系进行缺陷诊断，该方法不受电流影响，因而适用于负荷波动下的在线监测。在实验中采用应变片桥式电路测量预紧力，施加不同的预紧力进行绕组松动缺陷设置。利用锤击法测算油箱固有频率，考虑预紧力变化对油箱固有频率的影响，以不受共振影响的测点为有效测点。分析不同预紧力大小、不同电流情况下变压器有效测点信号的特征值，确定故障阈值与预警阈值，实现绕组松动缺陷诊断以及缺陷相定位。

Determine Method of the Transformer Winding Looseness Defeat Based on Vibration

Accurate defeat diagnosis on transformer winding looseness is investigated experimentally and theoretically in this paper. An eigenvalue of transformer winding looseness defeat is defined based on the pre-compression force. The eigenvalue vary monotonously with the pre-compression force, which is used in defeat diagnosis. This method is suitable for on-line monitoring under load fluctuations for the reason that the eigenvalue is unaffected by the current. In the experiments winding looseness faults are set by different pre-compression forces which are measured by the bridge circuit consisted of strain gauges and resistors. Hammering method is used to measure the natural frequency. The impact of pre-compression force's changes on the natural frequency is explored. Effective measurement points are not influenced by the resonance. Defeat threshold values and warning threshold values are selected after analyzing the characteristics of the effective measurement points under the circumstance of different pre-compression force and current to achieve winding looseness defeat diagnosis and defeat phase localization.