Partial discharge diagnostics — Critical steps towards on-line monitoring

For many decades the measurement of partial discharges (PD) in electrical apparatus has been used to detect insulation faults and hence to ensure reliable operation of high voltage assets. Whereas PD measurements used to be performed in factory or off-line only, there is now a strong trend to apply the technique also on-line. We have now reached a stage where PD measurement and analysis are proposed more and more as tools to ensure reliability of the modern (smart) grids. In this paper, developments in on-line monitoring of PD will be described and the important steps in performing such on line measurements will be identified. Further, the benefits are shown of implementing this technique for smart grid reliability.