M. Huzmezan

On-Line Partial Discharge Detection and Monitoring of a 110 kV/6 kV Power Transformer in a Refinery

During routine on-line partial discharge (PD) spot testing of high-voltage (HV) cables in a European refinery, unexpected PD activity was detected from a connected 110 kV/6 kV, 63 MVA power transformer. Follow-up investigations and on-line PD monitoring identified multiple PD activities originating from the active part of the transformer. This paper presents the measurement methodology, permanent sensor installation, comparison with dissolved gas analysis (DGA), and benefits of on-line monitoring for predictive maintenance of aged transformers. Results demonstrate that continuous PD monitoring provides superior insight into the insulation status and supports effective asset management in industrial facilities.