Analysis of Muara Tawar CCPP Block 1 Steam Turbine Vibration

Abstract

Condition monitoring of steam turbine enables early detection of faults and avoid unexpected breakdowns. Vibration analysis has gained much attention in the field of condition monitoring because of its accuracy in detecting faults and its ability for proper diagnosis of the faults. Muara Tawar CCPP block 1 has a steam turbine generator with a capacity of 215 MW. Steam turbine roll after inspection shows high vibration occurs on bearing 1. This study aims to find the cause of this high vibration and provide recommendations to avoids such symptoms. The vibration data used in the analysis are obtained from vibration analyzer tools associated with vibration monitoring systems. It is found that the amplitude of vibration at rotational speed frequency (1X) increased and phase angle changes at a constant speed. The vibration level at the coast down is higher than the observed vibration level at run-up. There is a shift in the position of critical speed which indicates a change of rotor stiffness. It is concluded that the high vibration is likely by a thermal bow on the rotor. The thermal rotor bow is caused by a light partial rubbing between rotor and labyrinth seal on the stator.