STP998

    An Engineering Model for Streaming Electrification in Power Transformers

    Published: Jan 1988


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    Abstract

    An engineering approach to assessing static electrification phenomena in power transformers is presented. A theoretical model is developed to estimate streaming currents and space charge accumulation around the hydraulic oil flow loop in a three-phase transformer. The streaming current model is applied to a 345-kV, 240-MVA three-phase auto transformer with shell form winding design. The influence of space charge on the electric field and potential distributions in the upper plenum is modelled by a one-dimensional theory. Significant electric stress enhancement at coil edges on alternate half cycles of applied a-c stress is predicted for the 240-MVA transformer. Potential failure modes in power transformers due to static electrification are discussed.

    Keywords:

    transformers, power, electrification, streaming, current, shell form, core form, charge, static, failure, oil, paper


    Author Information:

    Roach, JF
    Senior research scientist, Research and Development Center, Westinghouse Electric Corp., Pittsburgh, PA

    Templeton, JB
    Manager, Shell Form Design, Power Equipment Division, Westinghouse Electric Corp., Pittsburgh, PA


    Paper ID: STP26426S

    Committee/Subcommittee: D27.05

    DOI: 10.1520/STP26426S


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