Insufficient power of Hydro Power Plant of Hydro Power Plantand its solution
Insufficient power of the turbine means that the power of the turbine cannot reach the guaranteed power under the running head.
1. The main reason for the insufficient power of the unit:
The reasons for the insufficient power of the turbine or the decrease in power include both hydraulic and mechanical aspects; design and manufacturing aspects, as well as installation and operation management aspects.
1. The air inlet trash rack of the unit is blocked, and the area is large, which results in an increase in the hydraulic loss of the water inlet and a reduction in the overflow area, which leads to a decrease in overflow.
2. The diversion pipe canal has grown weeds, adsorbed shellfish microorganisms or severely formed maize, the hydraulic loss increases, and the overflow area decreases, resulting in reduced overflow.
3. The flow path of the runner of the small Francis turbine is narrow and twisted, which is easily blocked by gravel and debris, which affects the power of the turbine. When the interval between the trash racks is too large, debris is likely to enter the runner with the water flow; if there are debris and debris falling in the diversion channel, the runner will also be blocked.
4. Due to silt wear, cavitation damage or changes in the airfoil shape after maintenance, the hydraulic loss increases and the turbine overflow decreases, resulting in a decrease in the turbine power.
5. The submerged depth of the draft tube outlet is not enough, so that the flow capacity of the runner decreases, resulting in a decrease in the power of the turbine.
6. The installation height of the impulse turbine runner is not enough, so that there is not enough ventilation height between the runner and the downstream tail water level, causing the power of the unit to decrease.
7. The main components of the unit are naturally aging, and the bearing capacity is reduced, so that the unit cannot deliver the rated power. According to foreign reports, the natural aging of the main components of the turbine will reduce the efficiency of the turbine by 2% -3%.
Second, the solution
1. Generator capacity expansion
According to the comprehensive characteristic curve of the operation of the turbine, when the operating head is higher than the design head, the power of the turbine is mainly limited by the capacity of the generator, and the opening of the guide vane does not reach the maximum opening at this time. If the generator has the potential for capacity expansion, and The turbine cavitation performance, structural strength and unit adjustment and maintenance calculation meet the requirements. When the operating head is higher than the design head, the guide vane can be opened to increase the turbine power and increase the unit power.
2. Renovate the existing runner
By repairing the existing runner, the overcurrent capacity of the turbine can be improved, thereby increasing the power of the unit. After transformation, the cavitation and cavitation performance of the runner must be verified by model tests.
