CONDITION MONITORING OF A TURBOSET BY MEASUREMENT OF ITS TORSIONAL VIBRATION

The paper presents the idea of mechanical power measurement by measurement of the angular twist of the shaft. The measurement is based on analysis of pulses from two disks, installed at two ends of the machine. It gives accurate information about changes of the rotational speed as well as the twist angle of the shaft. Next, the paper presents developed data processing algorithms. The proposed method is discussed and shown applicable for measurement of the overloads of the power generation turboset. The implementation of the method requires installation of two disks at both ends of the shaft line. The simplified method of overload monitoring based on the dynamic speed, measured 60 times per revolution is also proposed and discussed. The method was validated on a test rig with two disks and on the 225MW generator with one disk. Even in such a simplified configuration, it was possible to extract sudden changes of the load and the resonant frequencies of the shaft line torsional vibrations.