3D Electric Field Modelling of UHV Class AC Composite Transmission Line Insulators

Silicon rubber composite based insulators are now widely used in UHVAC transmission line due to their antifouling property and easy installation. As they have a light weight design, transportation of these insulators becomes very easy in UHVAC transmission line projects. As the operating voltages increases and reaches to UHV class, uniformity in the potential and electric field distribution becomes extremely critical due to complex geometry configuration and aging factor also plays a critical role. This paper provides an overview of the voltage and electrical stress distribution in the 765 kV UHVAC composite transmission line insulators. Factors that would affect the long term performance and influence in the short term operation are also discussed. Modelling and E-field magnitudes determined are presented for tension type insulator design having maximum complexity in model geometry.