An Analysis of the Impact of Rotor Winding Interturn Short Circuits on Turbine Generator Operating Variables

• Published in: Electric power components and systems Vol. 43; no. 6; pp. 674 - 684
• Main Authors: Yucai, Wu, Yonggang, Li, Heming, Li, Wenjing, Zhang
• Format: Journal Article
• Language: English
• Published: Philadelphia Taylor & Francis 03.04.2015; Taylor & Francis Ltd
• Subjects: ANSYS simulation; Circuits; Electric power; electromagnetic torque; Electromagnetics; Excitation; exciting current; Finite element analysis; generator; Generators; Mathematical analysis; Mathematical models; mesh; Motors; Reactive power; rotor winding interturn short circuit; Rotors; Short circuits; Turbogenerators; Variables; Winding
• ISSN: 1532-5008; 1532-5016
• DOI: 10.1080/15325008.2014.999144

Abstract- In this article, the finite-element method is used to study the impact on a generator's electromagnetic torque by the position and level of a rotor winding interturn short circuit. The rules involving changes to the exciting current and the reactive power of generators are analyzed under the given adjustment patterns. The results of this study show that the saturability of ferromagnetic materials reduces the torque undulations that occur during the rotor winding interturn short circuit fault and that it improves the static stability of generators. Both the simulation experiment and the real case of a rotor winding interturn short circuit demonstrated that when a rotor winding interturn short circuit happens in a turbine generator, the generator can maintain its static stability by adjusting its state variables. This results in an increased exciting current and a decreased reactive power. The analytical method described herein allows accurate prediction of the change limits of the exciting current and the reactive power, enabling better diagnosis of the rotor winding interturn short circuit based on the two variables.