METHOD AND SYSTEM FOR MONITORING SUB-SYNCHRONOUS TORSIONAL OSCHILLATIONS OF A SHAFT LINE OF A STEAM TURBINE

摘要

A method for monitoring sub-synchronous torsional oscillations of a shaft, line of a steam turbine, comprising the steps of: - measuring (112) a rotational speed of said shaft line over a period of time and generating, from the measured rotational speed, a signal representative of said rotational speed over said period of time , - performing (122) a spectrum analysis on said signal to determine, for at least one given frequency, an amplitude of variation of said rotational speed at said given frequency, - comparing (124) said amplitude with at least one predetermined amplitude threshold for said frequency, - generating (126) an alert signal if said amplitude exceeds at least one predetermined amplitude threshold.