ABSTRACT
This troubleshooting case study involves the high-pressure-intermediate-pressure (HP-IP) portion of a 240 MW, 60 Hz, 3600 rpm coal-fired steam turbine generator driveline of an electric generating unit. Originally designed as a base-load unit to operate at its rated capacity, it was subsequently relegated to load following as the plant owner commissioned its nuclear units. In the load-following function, this unit consistently experienced excessive rotor vibration in the 145–180 MW power output range. The author was retained to analyze and diagnose the root cause for this excessive vibration problem. The resulting analyses showed that the problem could be cured by replacing the two HP-IP turbine journal bearings with a non-OEM (Original Equipment Manufacturer) superior design. After retrofitting the HP-IP rotor with the non-OEM bearing design recommended by the author, the load-cycling excessive rotor vibration problem was cured.
