Analysis of UHF PD monitoring data by means of normalized cross-correlation.

The paper presents a long-term monitoring example of an aged generator step-up transformer with several PD sources showing different activity. Monitoring data is recorded by the use of the electromagnetic PD measurement method, also known as the UHF-method. The phase resolved PD patterns of collected UHF measuring data are analyzed using cross-correlation. The method searches for characteristics of a typical pattern called template. PRPD patterns of the entire dataset are evaluated. The result is the time dependent occurrence of a specific pattern, respectively a specific PD source. [ABSTRACT FROM PUBLISHER]