Determination of the Corona Inception Voltage in an Extra High Voltage Substation Connector

Substation connectors play a key role in the reliability of power transmission systems. Despite this fact, their behavior has been rarely studied, especially in regard to electric stress. In this study the corona inception voltage of a complex-shaped 765 kV substation connector is calculated by using a three-dimensional finite-element approach combined with the semi-empirical Pedersen approach. The method proposed was previously validated by using available experimental data obtained from sphere-to-plane, concentric cylinders and point-to-plane non-uniform air gaps. To further validate the accuracy of this method, the corona inception voltage of the analyzed substation connector was obtained by making comparisons with experimental tests conducted in a high voltage laboratory. Results show the need to calculate the corona inception voltage for complex geometries and large air gaps. Using this proposed approach allows us to identify peak or stress points of the connector surface. Hence, this system strongly appears to be a valuable tool to assist the design process of substation connectors and other high voltage devices for minimizing corona activity.