Corona-free Hardware Assemblies for Bus Support Post Insulators for 1000 kV HVDC Test Facility

The paper details the design of corona-free line hardware for an Eskom ±1000 kV DC test facility. Two items are covered, namely filed control at post insulator connection flanges and bus support grading ring assembly. It is crucial that the facility is corona free such that device under test can be evaluated for corona performance even under adverse environmental conditions. Notably, the field intensification when the thunderstorm ambient electric field increases conductor surface gradients significantly and has been generally neglected in corona studies. The hardware is benchmarked against other international operational UHV designs.