An influence of voltage sag on non-utility generator shaft torque

Toshihisa Funabashi*, Hitomi Otoguro, Takayuki Tanabe, Goro Fujita, Kaoru Koyanagi, Ryuichi Yokoyama

*Corresponding author for this work

    Research output: Chapter in Book/Report/Conference proceedingConference contribution

    8 Citations (Scopus)


    An influence of the voltage sag on the shaft torque of the non-utility generator connecting to the utility system is investigated. During the oscillation of the generator electromagnetic torque, the mechanical shaft torque also oscillates according to the mechanical oscillation modes. In this situation, the shaft might be damaged. Three phase voltage sags are simulated by using ATP-EMTP, changing the fault point impedance and the short-circuit impedance of the utility system while the transformer impedance and the generator parameters are kept constant. The state equation of the generator mechanical system is investigated by using MATLAB/SIMULINK. Numerical simulation results show that the waveform of the electromagnetic torque is influenced not only by the fault point impedance but also by the short circuit impedance of the utility system, and thus a special condition of both impedances, in which the shaft torque has a maximum amplitude, could be found.

    Original languageEnglish
    Title of host publicationProceedings of the IEEE Power Engineering Society Transmission and Distribution Conference
    Number of pages6
    Publication statusPublished - 2000
    EventProceedings of the 2000 Power Engineering Society Summer Meeting - Seattle, WA
    Duration: 2000 Jul 162000 Jul 20


    OtherProceedings of the 2000 Power Engineering Society Summer Meeting
    CitySeattle, WA


    • Non-utility generator
    • Shaft torque
    • Voltage sag

    ASJC Scopus subject areas

    • General Engineering
    • General Energy


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