Electric stress on the surface of conductors in an Extra High Voltage substation

Abstract

In high voltage equipment and substations, the electric field distribution on the surface of the conductor is important from the point of designing the insulation systems. In outdoor substation, the atmospheric air acts as an insulation medium and the electric-fields (e-fields) on the surface of the conductors should not exceed the breakdown strength of air (2122 kV/m rms). Based on the analysis of surface e-fields of substation conductors, one can adjudge whether any redesign in terms of conductor effective radius and clearances are required. One such analysis of surface e-fields in a 765 kV substation in central India is carried out. Charge Simulation Method (CSM) is used as a numerical technique. The surface e-field plot on the substation conductors are reported. The highest e-fields are on the surface of transmission line conductors with 1504 kV/m. Thus, the design should work corona free.