The Mechanism Study Of Torsional Modes Instability Resulting From Electromechanical Coupling Under Large Disturbance

This paper makes an overview of the reasons, corresponding analysis methods and countermeasures for shaft torsional oscillation. The "2.20"fault of Zhangze power plant is analyzed. Applying rotating vector method and resonance theory, the fault mechanism of Zhangze power plant electrical part is arrived at. The NO.3 shaft system torsional vibration characteristic of Zhangze plant is computed through transfer matrix method and eigenvalue analysis method. The electromechanical coupling system model is set up by simulation software PSCAD/EMTDC. Shaft system rupture mechanism of Zhangze power station is arrived at through a great deal of simulation computations. The methods on the research of torsional vibration stability are summarized and the deficiencies in present research are pointed out. The instability mechanism of shaft system is analyzed and the concept torsional vibration stability limit is put forward. A new modeling method of shaft system is brought forward to make the simulation more accurate. The applicability of complementary -cluster energy-barrier criterion on researching stability of shaft system torsional vibration is discussed.