Research on mechanical properties of pressboard structure for transformer under compression with different mechanical stress loading parameters

High density pressboard made of cellulose is a crucial component of power transformers because it combines good mechanical and electrical insulation properties that are well suited to power transformer design requirements. It is critical to characterize the mechanical properties of pressboards under various operating conditions in order to ensure a properly functioning transformer. In this paper, the stress-strain curves for pressboards with different total thickness and different mechanical stress loading parameters were studied. According to the fitting curves obtained by the tests, it can be found that the value of the strain of the thinner pressboards is 0.05 larger than that of the thicker pressboards under the same stress. In addition, the different loading speeds will affect the deformation of the pressboards. The faster loading speed in the range considered in this paper, the larger strain of the pressboards is. Through analysis, the relationship between the nonlinear coefficient of the mechanical properties of the pressboards and the deformation strength of the winding is a power exponential distribution.