Numerical Methods for Multiphysics Modeling of Plasma Due to Electrical Discharge

Condition monitoring of the insulation system is an important tool for monitoring the insulation performance. One of the important diagnostic tools used for condition monitoring of the insulation system is the electrical discharge measurements. Various experimental works have been done in this regard; however, the micromechanism of charge migration and electric field distortion is still not clear. The simulation studies offer this advantage as the microscopic mechanisms and conditions influencing discharge events can be easily monitored. In this article, various numerical methods used for discharge modeling in terms of plasma-based electrical discharge are discussed, along with their applicability using multiphysics coupling. From the models discussed, the most suitable model is chosen to simulate the discharge characteristics under various conditions. The effects of void shape distortion on charge distribution and electric field distortion inside the void region and the insulation materials are discussed, indicating that when the void gets distorted in the direction of the electric field, the probability of discharge increases because of more migration of ions. The effect of thermal aging on the field and charge distribution is also analyzed using different insulating materials, and a comparative analysis is done. This study thus helps in understanding the physical mechanism of discharge dynamics and provides a theoretical reference helpful in maintaining and achieving optimum performance of transformer insulation.