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The ability of a detailed RLC model of a winding to calculate the transfer function (TF) and to demonstrate the effects of various winding damages on TF has been proven on small laboratory windings by previous studies. However, this ability is not adequately known for real high-voltage windings. Hence, a 400 kV disc winding consisting of 86 discs is used in this work to study, whether the detailed model is able to represent the behaviour of large-power windings in a TF form. In addition, disc space variation (DSV), known as a frequently occurring mechanical damage in transformers, is analysed experimentally and mathematically. The accuracy of the model to identify the DSV is verified with the help of the measured TFs. [ABSTRACT FROM AUTHOR]

This contribution describes an evaluation method for phase resolved patterns of partial discharges over time. Therefore, their specific shape characterizes patterns in question. The method searches for these characteristics within PRPD patterns by comparing characterization and PRPD using 2-dimensional cross-correlation. Crosscorrelation represents a measure for the similarity between different PRPD patterns. A use case determines the usability of the method in practice. The result is the time dependent occurrence of specific patterns, respectively specific PD sources. Long-term monitoring data of an aged generator step-up transformer with several PD sources of varying activity is used as PD dataset. PDs are recorded by the use of the electro magnetic PD measurement method, also known as the UHF-method. [ABSTRACT FROM AUTHOR]