Experimental research on thermal aging effects on microstructure of transformer paper

To investigate thermal aging stress effects on microstructure of transformer paper for more accurate analysis of mechanical strength and insulation performance of oil-paper insulation, the accelerated thermal aging experiment is performed on oil-paper samples in this work and some samples of different aged states are obtained. The surface micro-topography of paper samples is observed by Scanning Electron Microscope (SEM) and the changes of molecular structure are analyzed by Fourier Transform Infrared Spectroscopy (FTIR). Experimental results show that thermal aging stress brings significant changes to microstructure of paper fiber. The cellulose fiber becomes thinner and shorter. In addition, the molecular structure of cellulose fiber and the quantity of some function groups change obviously.