A comparative study on the performance of domestic cellulose based pressboards for use in Transformers

The cellulose based pressboards from four well-known suppliers in China, which are Changzhou HuaDian Insulation Material Co., Ltd (HD), TaiZhou XinYuan Electrical Equipment Co., Ltd (XY), Hunan GuangXin Electrical Technology (GX) and ShangHai YaZhong Trade Development Co., Ltd (YZ) were analyzed and compared. The guarantee value of Figeholm's pressboard was taken as a reference. Mechanical results show that most pressboards have excellent tensile, compressive and flexural properties except for YZ pressboards. The ply adhesion was also studied by simple loading method to verify the bonding effect and only XY pressboard show no sliding. Electrical results show that all pressboards have a similar electrical strength while HD and XY pressboards show relatively lower dissipation factor value. Based on the mechanical and electrical performance, XY pressboards are considered to be better as compared to others and competitive to Figeholm's products.