Characteristic Analysis of Point Discharge Current Pulse Using Numerical Simulation Based on Fluid Dynamics Model

摘要

Partial Discharge (PD) can not only indicate the insulation degradation of high voltage electrical equipment, but also enhance defect severity and lead to premature failure of equipment. In order to improve our physical understanding of PD process, the micro mechanism of PD can be studied by constructing simulation models. Moreover, from the perspective of analyzing the simulated PD current pulse, a theoretical basis for the further research on detection of PD signal is provided. In the paper, a fluid dynamics model based on drift-diffusion equations of charged species is utilized to simulate the microscopic process of point discharge in air, which is thought to be a common type of PD. From the simulation model, the first discharge current pulse is calculated and a detailed analysis of the charged particle concentration and electric field intensity distribution of the four stages of the pulse is performed. In addition, considering the rising and falling edge of the pulse being controlled by different main physical mechanisms, the data fitting method is used to abstract a Gaussian-Power segmented function mathematical model from the simulated point discharge current pulse. The fitting result of a measured point discharge pulse signal verifies the validity of the mathematical model with R-square larger than 94% and root mean square error less than 0.09.