Study on the fatigue effect of transformer pressboard and its influence on winding mechanical stability

Summary

Fatigue effect on transformer windings not only exist in winding conductors but also exist in spacers. Previous study on the fatigue of transformer from short circuit are mainly concentrated on conductors, because they are easily to be identified from short circuit impedance and pendant-core examination. Study on the mechanical property of spacer mainly focus on the viscoelasticity and dynamic response of spacer under short circuit. However, the change of mechanical property of pressing board during several short circuits have not been mentioned yet. In this paper, 10 cyclic loading with its value from 0-5MPa are applied on spacers which are T1 board from Weidman Company. Then, the relationship between the change of mechanical property under multiple impacts and the clamping pressure are discussed. The conclusion is that spacers may become thinner and thinner under large cyclic pressure at 0.03%/cycle increase of strain and the clamping pressure is closely related to the strain change and initial strain. For initial clamping pressure at 1.5MPa, the change of clamping pressure is 0.4% per 5MPa impact which is quite optimistic than the fact.

Additional informations

Authors

Gurevich, MÜLLER, CHIGRI, GUERREIRO, STUNDER

Keywords

Transformer, Pressboard, Winding, Fatigue Effect, Mechanical property