Steam Turbine Incident Script Steam Turbine Operating at 93 MW and 3000 RPM The steam turbine was operating normally, spinning at 3000 RPM under a load of 93 megawatts. Suddenly, the grid frequency surged from 50 to 53 hertz. This caused the rotor to accelerate rapidly, reaching 3200 RPM and triggering dangerous shaft vibrations. These vibrations caused the seal strips—thin 4mm wires embedded in grooves around the rotor—to begin dislodging. Some strips deformed and were ejected from their grooves, colliding with the blade carrier and generating intense friction and sparks. Ultimately, the unit tripped due to mechanical damage caused by overspeed. This incident highlights the importance of overspeed protection and rotor-seal alignment integrity in steam turbine operations.