When the following situations happen, the steam turbine shall be immediately stopped:  

1. The rotating speed exceeds 3360 r/min, the emergency interceptor does not act. 

2. The vibration of bearing seat exceeds 0.07 mm. 

3. The main oil pump is in failure. 

4. The control system is abnormal. 

5. The axial displacement of rotor is more than 0.7 mm, the axial displacement interceptor or axial displacement monitoring device do not act. 

6.The return oil temperature of bearing is over 70 ℃ or the metal temperature of bearing bush is over 100 ℃. 

7. Oil system is on fire and cannot be put out. 

8. The oil level of oil tank suddenly decreases below the minimum oil level. 

9. Water impact occurs. 

10. The unit has abnormal noise. 

11. The main steam pipe bursts. 

12. The condenser vacuum has dropped below 0.06 MPa (450 MMHG). 

13. The extraction steam pressure exceeds the limit value and the relief valve does not act.