HVDC Corona Space Charge Modeling and Measurement

An electrometer circuit is designed and developed to measure the ion-space charge created during HVDC corona events. The interpretation of the electrometer output and visualization of various discharge processes are facilitated by a particle-in-cell computational code. The time it takes for the space charge to be created during a single monopolar corona event to reach the ground electrode in a corona test method is computed for a small corona cage, a short test line, as well as a large corona cage. This complements results obtained by the authors in another paper where it is shown that a small corona test cage cannot be used to predict the RI performance of HVDC conductors due to the space charge buildup in the small electrode gap.