What is the purpose of corona shields on EHV lines?

The purpose of corona shields on Extra High Voltage (EHV) lines is primarily to prevent the concentration of the electric field at points where the electrical potential is highest, such as at the tips of conductors. When the electric field intensity exceeds a certain limit, corona discharge can occur, leading to energy loss in the form of light, sound, and heat, as well as the potential for damage to the insulation and surrounding structures.

By using corona shields, the electric field is distributed more evenly, which minimizes localized high field strengths. This helps to enhance the overall efficiency and longevity of the power transmission system. As a result, the shields effectively mitigate issues related to corona discharge, ensuring smoother operation and reducing the risk of power losses and disruptions.

This function of corona shields is crucial for maintaining the integrity of EHV lines, particularly as these lines carry more power over greater distances and must operate reliably under various environmental conditions.