电力变压器直流偏磁检测方法研究

电力变压器发生直流偏磁会引起变压器异常运行甚至损坏，而现有的方法不能准确检测其偏磁状态。本文提出一种新结构的磁通门传感器，该传感器从变压器铁芯磁通中提取部分分量，采用脉冲幅值法量化传感器的检测线圈输出信号从而表征变压器偏磁程度。作为验证，本文设计样机并采用10kVA电力变压器进行实验。实验结果表明，当外加偏置电流从0A到0.5A变化时，磁调制输出信号幅值呈单调变化。

Research on Direct Current Bias Magnetic Detection Method of Power Transformer

Direct current (DC) in power transformer can initiate its abnormal operation, and even damage the transformer. However, the existed methods cannot accurately detect the bias magnetic state of the transformer. A new structure fluxgate sensor is proposed in this paper. The sensor extracts fractional flux from the transformer and uses the self-oscillating fluxgate principle to generate excitation current. In addition, the output signal of the sensor$#@%%$s detection coil is quantified, using the pulse amplitude method, to characterize the degree of transformer bias. As a verification, a prototype is designed to experiment on a 10kVA power transformer. The measurement results show that the magnetic modulation output signal changes monotonously as the applied bias current varies from 0A to 0.5A.