Reduction of the Background Noise for Partial Discharge Measurements in Transformer Test Circuits fed by Static Frequency Converters

Conference: UPEC 2011 - 46th International Universities' Power Engineering Conference
09/05/2011 - 09/08/2011 at Soest, Germany

Proceedings: UPEC 2011

Pages: 6Language: englishTyp: PDF

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Moessner, K.; Leibfried, T. (Karlsruhe Institute of Technology, Institute of Electric Energy Systems and High Voltage Technology, Karlsruhe, Germany)
Stolz, J.; Gamlin, M. (Haefely Test AG, Basel, Switzerland)

As static frequency converters by default emit electromagnetic interference to a certain extent, partial discharge measurements in transformer test circuits fed by static frequency converters are affected by a high background noise level, if no appropriate measures are taken. In this paper the emergence and propagation of the common-mode noise are presented and possible solutions are discussed, introducing the application of a step-up transformer with static shielding layers. A laboratory setup was used to assess the spectral properties of disturbance emitted into a distribution transformer test circuit by a standard static frequency converter designed for drive applications. The impact of static shielding layers in the step-up transformer on the coupling between the winding systems was examined by a swept frequency response analysis. The feasible reduction of the background noise level for partial discharge measurements obtained by static shielding layers and additional measures was assessed experimentally.