A novel approach to high voltage substation surveillance using radio frequency interference measurement

The deployment of radio frequency interference (RFI) measurement has gained increasing acceptance as a front line, non-invasive technique to assess the condition of individual high-voltage (HV) electrical equipment items as part of a substation surveillance program. However, successful detection and discrimination of low-repetition rate discharges that typically accompany electrical deterioration is constrained by the capabilities and limitations of the field spectrum/RFI analysers used and the electro-magnetic interference (EMI) measurement techniques supported. This paper presents a novel approach to RFI measurement and assessment that is more sensitive to the RFI emissions that typically accompany electrical deterioration and provides more effective discrimination of the discharge phenomena from the ambient frequency spectrum and noise. Case studies from substation surveillance are presented to demonstrate the effectiveness of the approach. The technique is effective with a wide range of HV equipment and is less reliant on expert knowledge for a practicing engineer to confidently characterise and trace electrical deterioration with a high degree of confidence.