This paper investigates the effect of the voltage variations and the change of solid insulation material on the initiation and propagation of Electrical Tree (ET) through solid dielectrics based on the application of Finite Element Method (FEM) approach using the environmental domain of [COMSOL Multiphysics ] program as an innovative way to be used in the complicated study of Electrical Treeing Phenomenon (ETP). This research provides an innovative solution to suppress the initiation point of ET and suppress its growth rates using a composite solid insulation material of Poly – Vinyl Chloride (PVC) and Cross – Linked Polyethylene (XLPE) regardless to the mechanical features of this composition. In this research, the study cases are conducted for High Voltage (HV) and Extra High Voltage (EHV) power system networks as the effect of ETP is to be observed clearly. The simulation model is used in this research to imitate the proposed hyperbolic needle – plane system. Case studies are compared between each others to validate the results