In order to reveal and evaluate the growth characteristics of DC grounded electrical trees insulated by cross-linked polyethylene (XLPE) cables

a dynamic growth model of periodic DC grounded electrical trees based on bipolar carrier theory is established. Then

the proposed model is used to simulate the electrical tree morphology at different voltages

and the results are compared with those from the actual electrical tree growth test and the traditional WZ model to verify the accuracy of the proposed model. Finally

in this paper

the growth characteristics of DC grounded electrical trees are further analyzed based on the dynamic growth model of electrical trees

and a method for evaluating the growth characteristics of electrical trees based on leakage current is proposed

that is

the leakage current change factor Jg is used to quantitatively characterize the length L of electrical trees and the fractal dimension Df. The results show that

compared with the traditional model

the electrical tree morphology of the proposed model is more consistent with the experimental images

the error of the fractal dimension and the experimental results is less than 8%

and the error of the expansion coefficient is within 20%. During the growth of electrical trees

the leakage current density shows a nonlinear growth trend with three-section characteristics

and is closely related to the evolution of electrical tree morphology. The leakage current change factor is significantly positively correlated with the length and fractal dimension of the electrical tree. The length and fractal dimension of the electrical tree can be evaluated and predicted by the form of the cubic function and exponential function of Jg

which provides a certain reference value for the defect monitoring of XLPE cable insulation.