Depressing Turbine-Generator Supersynchronous Torsional Torques by Using Virtual Inertia

Authors: Jong-Ian Tsai, Chi-Chuan Chen, Tung-Sheng Zhan, Rong-Ching Wu

Abstract:

Single-pole switching scheme is widely used in the Extra High Voltage system. However, the substantial negativesequence current injected to the turbine-generators imposes the electromagnetic (E/M) torque of double system- frequency components during the dead time (between single-pole clearing and line reclosing). This would induce supersynchronous resonance (SPSR) torque amplifications on low pressure turbine generator blades and even lead to fatigue damage. This paper proposes the design of a mechanical filter (MF) with natural frequency close to double-system frequency. From the simulation results, it is found that such a filter not only successfully damps the resonant effect, but also has the characteristics of feasibility and compact.

Keywords: Single-pole, Supersynchronous, Blade, Unbalance, filter

Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1333362

References:

[1] E. W. Kimbark, "Suppression of grounding fault arc on single-pole switched EHV lines by shunt reactor," IEEE Trans. PAS., vol. 83, pp. 285-290, March 1964.
[2] J. I. Tsai, "A New Single-Pole Switching Technique for Suppressing Turbine-Generator Torsional Vibrations and Enhancing Power Stability and Continuity," IET Proceedings - Generation, Transmission and Distribution, vol. 1, no. 5, pp. 804-810, Sept. 2007.
[3] S. O. Faried, "An adaptive short time compensation scheme for improving power system stability and reducing turbine-generator shaft torsional," IEEE Trans. Power Systems, Vol. 15, No. 2, pp. 785-790, 2000.
[4] J. Gonzalez, G. C. Kung, C. Raczkowski, C. W. Taylor and D. Thonn, "Effects of single- and three-pole switching and high-speed reclosing on turbogenerator shafts and blades," IEEE Trans. Power Apparatus and Systems, vol.103, no. 11, pp. 3218-3228, 1984.
[5] Power System Blockset for Use With Simulink User-s Guide, June 2001.
[6] Slow Transient Task Force of IEEE Working Group, "Modelling and analysis guidelines for slow transients. Part I. Torsional oscillations; transient torques; turbine blade vibrations; fast bus transfer," IEEE Trans. Power Delivery, vol. 10, no. 4, 1995.
[7] R Gerber, Theory of Electroacoustics, Salford, New York, pp.1-56, 1979.
[8] J. J. Grainger and W. D. Stevenson, "Power system analysis," McGraw- Hill, Inc. 1994.