What are the phenomena of turbine blade failure? What measures should be taken during operation to prevent blade damage?
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The phenomena of blade fracture include: (1) a sudden noise occurring inside the turbine or the condenser. (2) Sudden increase in vibration or shaking of the unit. (3) When the blades are severely damaged, to maintain a constant load, the steam flow rate must be increased, that is, the valve opening must be enlarged. (4) When broken blades fall into the condenser, they damage the cooling water pipes; as a result, the water level in the condenser rises, the conductivity of the condensate water increases, and the current drawn by the condensate pump increases. (5) Broken blades entering the extraction steam pipeline may cause valve sticking. (6) A metallic rubbing sound can be heard during coasting and turning operations. (7) The intermediate pressure increases during operation. To prevent blade damage, the following measures should be taken: (1) The power grid should operate at a normal frequency to avoid situations where excessive high or low frequencies cause certain blades to enter the resonance zone. (2) During operation, keep the steam parameters as well as the pressures and vacuums in various monitoring sections within normal ranges; if these values exceed the limits, operation should be carried out with reduced load. (3) Strengthen the chemical monitoring of steam and water. (4) During operation, strengthen the monitoring of vibrations to prevent the turbine from deforming due to uneven heating caused by cold water or steam ingress, or other factors, which may lead to a reduction in the dynamic and static clearances and resulting in localized rubbing. (5) During the major overhaul of the unit, a thorough and detailed inspection should be carried out on the damage to the flow-through components; records of any damage to the blades, shrouds, and struts should be kept, and adjustments to the blades should be made as necessary.
The phenomena of blade fracture include: (1) a sudden noise occurring inside the turbine or the condenser. (2) Sudden increase in vibration or shaking of the unit. (3) When the blades are severely damaged, to maintain a constant load, the steam flow rate must be increased, that is, the valve opening must be enlarged. (4) When broken blades fall into the condenser, they damage the cooling water pipes; as a result, the water level in the condenser rises, the conductivity of the condensate water increases, and the current drawn by the condensate pump increases. (5) Broken blades entering the extraction steam pipeline may cause valve sticking. (6) A metallic rubbing sound can be heard during coasting and turning operations. (7) The intermediate pressure increases during operation. To prevent blade damage, the following measures should be taken: (1) The power grid should operate at a normal frequency to avoid situations where excessive high or low frequencies cause certain blades to enter the resonance zone. (2) During operation, keep the steam parameters as well as the pressures and vacuums in various monitoring sections within normal ranges; if these values exceed the limits, operation should be carried out with reduced load. (3) Strengthen the chemical monitoring of steam and water. (4) During operation, strengthen the monitoring of vibrations to prevent the turbine from deforming due to uneven heating caused by cold water or steam ingress, or other factors, which may lead to a reduction in the dynamic and static clearances and resulting in localized rubbing. (5) During the major overhaul of the unit, a thorough and detailed inspection should be carried out on the damage to the flow-through components; records of any damage to the blades, shrouds, and struts should be kept, and adjustments to the blades should be made as necessary.