Effect of the Vertical Component of Movement on Slippage of a Power Transformer as Caused by Earthquakes

This paper describes slippage of power transformers as caused by earthquakes. Some power apparatuses were destroyed by the Great Hanshin Earthquake in 1995. One cause of damage was the failure of anchor bolts which led to slippage of power transformers from their concrete foundations. The forces applied to the anchor bolts and displacements of power transformers by the slippage are affected by not only the horizontal component, but also the vertical component of the earthquake. In this report, vibration analysis was carried out using various earthquake waves. Slipping conditions of a transformer under both horizontal and vertical components of an earthquake movement were clarified. It was found that the effect of the vertical component on slippage of the transformer was not so large.