直流偏磁对变压器振动噪声的影响

Research on Vibration and Noise of Transformers under DC Bias

取向硅钢片的磁致伸缩特性是引起变压器振动噪声的主要原因,并且直流偏磁在很大程度上加剧了变压器的振动噪声。本文首先测量了取向硅钢在不同磁密下的磁致伸缩蝴蝶曲线族,研究了轧制方向(RD)和垂直轧制方向(TD)磁致伸缩的特性,同时研究了直流偏磁对磁致伸缩特性的影响,然后用平均磁致伸缩曲线来模拟取向硅钢片的磁致伸缩特性,并将其应用到直流偏磁条件下一台160k V·A干式变压器空载振动的有限元计算。最后实验测量了直流偏磁条件下变压器铁心不同位置的空载振动,以及随着直流偏磁的增大,噪声声压级的值。综合有限元计算和实验测得的空载振动噪声值,分析了直流偏磁对变压器振动噪声的影响。

Magnetostriction in grain-oriented electrical silicon steel arises vibration and noise of the transformer core, especially when operating under direct current(DC) bias. In this paper, the anisotropy of magnetostriction of grain-oriented(GO) silicon steel sheets along the rolling direction(RD) and transversal direction(TD) deviating from RD 90° is measured based on a standard single sheet measurement system, and the single-valued curves of magnetostriction are obtained when incorporated with magnetic finite element(FE) analysis, then the vibrations are calculated through software. The vibration and noise are measured by experiments, the effect of DC bias on vibration and noise of transformer core is studied in detail.