Investigation of the Total Flow Rates in Oil Natural Transformer Retrofilling Scenarios

Xiang Zhang, Zhongdong Wang, Qiang Liu, Attila Gyore, Kevin Rapp

    Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

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    Retrofilling transformers with a new liquid has been considered as an option for life extension and/or uprating purposes. The determination of the new total liquid flow rate is of vital importance in assessing the effect of retrofilling on flow and temperature distributions in the winding, especially for ON transformers. This paper presents the determination of flow rate ratios for four liquids—a mineral oil, a GTL oil, a synthetic ester and a natural ester—in ON transformer retrofilling scenarios. Flow rate ratios among different liquids are provided for a simplified condition of linear radiator oil temperature variation. For a more realistic exponential radiator oil temperature variation, the detailed transformer geometric information is needed to estimate the total flow rate. In addition, a hydraulic winding network model is established to prove that “minor pressure losses” due to change of flow directions is indeed minor for ON transformer liquid flow conditions, justifying neglecting the minor losses in the deduction of the total liquid flow rate.
    Original languageEnglish
    Title of host publicationInternational Conference on Dielectric Liquids (ICDL)
    Publication statusPublished - 27 Jun 2019
    Event2019 IEEE International Conference on Dielectric Liquids - Rome, Italy
    Duration: 23 Jun 201927 Jun 2019


    Conference2019 IEEE International Conference on Dielectric Liquids
    Abbreviated titleIEEE ICDL 2019


    • ester
    • flow rate
    • GTL
    • Mineral oil
    • retrofilling
    • transformer


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