Investigation of radiometric partial discharge detection for use in switched HVDC testing

This paper reports on initial trials of a non-contact radio frequency partial discharge detection technique that has potential for use within fast switching HVDC test systems. Electromagnetic environments of this type can arise within important electrical transmission nodes such converter stations, so the methods described could in future be useful for condition monitoring purposes. The radiometric technique is outlined and the measurement system and its components are described. Preliminary field trials are reported and results presented for a discharge detected in part of the HV test system during set-up for long-term testing of a reactor. The calculated and observed locations of the discharge were in agreement to within 60 cm inside a test housing of diameter 5 m and height 8 m. Techniques for improving the location accuracy are discussed. The issue of data volume presents a considerable challenge for the RF measurement techniques. On the basis of observations, strategies for moving towards automated interpretation of the partial discharge signals are proposed, which will make use of intelligent software techniques