直流偏磁下电力变压器的振动特性

Analysis on Vibration Characteristics of Power Transformer Under DC Bias

为深入了解直流偏磁情况下变压器的振动特性,基于能量守恒理论,详细分析了变压器铁心的磁致伸缩应变特性及直流偏磁时的振动特性。通过搭建变压器直流偏磁试验平台,对直流偏磁时变压器励磁特性和箱壁振动特性进行测试,得到了励磁电流和振动信号随外加直流分量的变化规律。分析结果表明,励磁电流随直流分量的增加而增大,波形畸变程度加剧,有偶次谐波出现,且各次谐波含量呈现增加趋势但增幅各异。此外,振动信号中有不同程度的高次频率分量出现,且各频率分量幅值随直流分量的增加而增大。

To understand vibration characteristics of power transformer under DC bias in depth,based on the theory of conservation of energy the magnetostrictive stain properties of transformer core and its vibration characteristics under DC bias are analyzed in detail.Through setting up DC bias experiment platform of power transformer,the excitation characteristic of power transformer under DC bias and the vibration characteristics of its tank wall are tested to obtain the variation law of excitation current and vibration signal with additional DC component.Analysis results show that the excitation current increases with the increase of DC component,the extent of waveform distortion intensifies and even harmonics appear,and the contents of different orders of harmonics present the tendency of increase and the increasing rates are not same.Besides,there are high frequency components in the vibration signal and their amplitudes increase with the increase of DC component.