In this paper, we have considered the possibility of improving the electrophysical properties and heat resistance of dielectric cellulose paper (a component of high-voltage paper-impregnated insulation) by using a biopolymer as a basis and as a modifier for traditional cellulose. We have obtained prototypes of insulating papers with enhanced electrophysical properties allowing to improve the performance characteristics of a solid dielectric. We have established that modification affects the stability of a solid dielectric against long thermal exposure in an electrical insulation fluid. We have considered the prospects of the technological method of biopolymer disintegration, which can be used in industrial production of cellulosic dielectrics. We have established that it is expedient to create new-generation cellulose dielectrics, which are a valuable alternative to plant cellulose obtained from coniferous woods, differing by their increased electrophysical characteristics.