Adjusting the electric field and voltage distribution along a 400 kV transmission line composite insulator using corona ring

Nowadays, composite insulators are widely utilized in power systems because of their undeniably important advantages over non-ceramic insulators. Effective use of these insulators, however, entails adjusting the voltage and e-field distribution along them which are inherently much more non-linear comparing to non-ceramic insulators. In this paper, corona ring design for a 400kV composite insulator is investigated aiming at e-field and voltage regulation along the insulator. The analysis is based upon Finite Element Method (FEM) and the results obtained through the simulations. The effects of the corona ring´s design parameters on e-field and voltage control are studied. Appropriate dimensions and position of the rings are then determined for effective adjustment of the voltage as well as e-field distribution. Moreover, the simulation is also conducted for double corona rings at the energized end and the results are compared to those in the case of single ring.