The possibility of limiting the amplitude of the turbine shaft line torsional vibrations by introducing additional units into the automatic excitation regulator of the generator is studied. The mathematical model of the power system, including the electric and mechanical subsystem of the turbine, is developed. The structure of an automatic excitation regulator is given. A quadratic controller is implemented that makes to reduce the amplitudes of torsional oscillations. The system is modeled without the controller and with it. The dependence of the amplitude of the torsional oscillations on the gain factor of the controller is obtained. By this dependence it can be concluded that the increase of the coefficient of the quadratic controller makes it possible to reduce the amplitude of the oscillations.

Limitation of Weakly Damped Shaft Lines Power Stations Torsional Vibrations at Subsynchronous Frequencies in Distributed Generation Power Systems

Information Hiding Technology in Power System Network Security

Low-frequency (sub-synchronous) oscillation effects in geared gas turbine units that lead to the shutdown of the units and to breakdown of the power system are examined. The reasons are complicated and depend on the operation of variable frequency drives and the design features of the gas turbine unit. Data from tests by the firm JSC “Diamekh 2000” are presented. This paper examines the features of oscillations in the reducing gear when resonant torsional oscillations are present in the drive sleeve. It is proposed that gas turbine units without, rather than with, gearing be used in isolated power systems for operation with a variable frequency drive and for maintaining the balance between the nonlinear and linear components of the load.

E. S. Trunin

Papers

Torsional Oscillations in a Gas Turbine Unit and the Possibility of Collapse of an Isolated Power System