Study On The Dynamic Characteristics Of Supporting Structure For Power House Structure Of Two-row Placed Units

The structural vibration problem of hydroelectric station is a key problem in the design and operation of power station. Duo to the vibration, the benefit of power station system is affected. Long-term vibration may cause fatigue damage of the structure and limit the operation of units. Therefore, in the operation and design of power station, the vibration must be considered in detail and the measures to control and prevent the vibration need to be adopted. By now, a lot of deficiencies still exist in the research of structural vibration problem of hydroelectric station and unit, especially in the research of power house of two-row placed units. The study on the dynamic mechanism of the arrangement in parallel units and the double-layer tail pipe is still lacking. In the paper, the dynamic characteristics of supporting structure for hydroelectric house is analyzed according to Lijiaxia project, the largest power house of two-row placed units in the world at present. The author has accomplished the following researches:(1) The influence of structure hole, galleries, turbine case and interlayer cushion on the dynamic characteristics of power house is analyzed.(2) The calculation method of additional mass is investigated. The influence of additional mass on the dynamic characteristics of supporting structure is also obtained.(3) The determination of the simulating scope for calculation model is very important. The paper conducts studies on the problem and proposes some valuable suggestions.(4) The effect of material parameters is analyzed.(5) 3－D FEM model of the power house structure of two-row placed units and the corresponding 3－D FEM model of the power house structure of one-row placed unit are constructed. The difference of these two structures in dynamic character is compared and the reason is analyzed.(6) The vibration-sources of Lijiaxia hydropower station and the formation mechanisms of the vibration-sources are investigated. Then the structure resonance vibration is checked. According to the check of the structure resonance vibration, it is shown that the supporting structure for the power house of two-row placed units have some advantages in dynamic stability. (7) The seismic responses of the supporting structures of two-row placed units and one-row placed unit are calculated. The dynamic responses during the operation of units are also analyzed.