Coordination of torsional controller for turbine-generator system operation

Under the action of disturbance in power system, turbine-generator shaft are subjected to mechanical stress caused by severe torsional torques. Shaft torque is proportional to the shaft twist, which is caused by angle difference between both ends. However, observing the angle difference in an actual generation system is difficult technically. On the other hand, measuring rotational speed of the shaft ends is relatively easy. Then if the shaft torque could be estimated effectively, it would be used in order to control the rotational speed for shaft torque reduction. This paper proposes a parametric analysis for shaft torque estimator based on observer against changes of load conditions in-house type generation system. Firstly, this paper proposes shaft torque observer for rotating type generation system, and discusses about relation between observation signals and accuracy of the estimated values. Secondly, a parametric analysis is conducted for shaft torque estimator against load change.