Risk Assessment Based on Sensor Fusion for the Ion Current Measurement as a Diagnosis Method for HVDC Systems

To ensure the reliability of transmission networks integrating novel HVDC equipment, risk assessment characterises maintenance based on the equipment’s condition. For condition rating, this study uses the ion current measurement method instead of partial discharge measurements due to challenging research regarding partial discharge and the correlation of faults under HVDC. As the ion current measurement method is suitable to detect faults and changes in a gas-insulated equipment’s condition under HVDC, this study fuses the ion current measurement results with photos from a corona scope. This sensor fusion process is based on the Evidence Theory (Dempster-Shafer Theory), setting up a Fault Detection Model and a Fault Distinction Model for a needle-plate-arrangement. For both models, the investigation links characteristics of ion currents to atoms hinting at different faults and fault causes. The outcomes from both models show a reproducible and robust risk assessment based on belief functions of whether an HVDC arrangement’s condition has changed under the influence of particle contamination in comparison to a reference condition.