1Overview The Daxia Hydropower Station is located in the upper reaches of the Yellow River in Gansu Province. Riverway 651 from Lanzhou City is the first cascade hydropower station planned and developed in the Longqing reach of the upper Yellow River and is equipped with 4 hydroelectric generating units with 75 rivers. The turbine model is 2223700, the generator model is 5 corpses 756 to 350. The generator is in the form of a vertical phase air-cooled semi-umbrella structure. The entire unit is a shaft turbine, a turbine is a runner, a turbine is a large shaft generator, a shaft is a generator rotor and the generator is on the upper shaft. Constituted in other segments.
The shaft has a total length of 21.48, in which the major shaft length of the turbine is 5.7 and the generator shaft length is 5.9. The stator and rotor of the generator are assembled on the site. The stator frame segment is welded after the site is welded into a full circle, and the core is laminated after being laminated. line. Rotor split rotor center rotor support common lobe, secondary ribs in the construction site, welding laminations, mounting magnetic poles, anti-machine guide bearing installed in the center of the frame body, bearing bushes with adjustable wedge plate structure The child frame has 12 jacks with shear cutters to transmit radial force to the foundation, the generator thrust bearing adopts flexible fuel tank support knots, and the thrust washers are 12 elastic metal fluorine watch bushes, water guide bearings use self-circulating dilute oil lubrication cartridges. Tile structure.
2 asks that the upper guide swing is greater than the design allowable value, and the maximum allowable design value is 1. The design allowable value is 0.3 at maximum. During this period, the crew was forced to stop for 4 times in March and December of the month of March 1997. Adjust the guide shoe clearance to reduce the yaw. The effect is not obvious, 1 unit has been put into operation since 1997. 6 months, and in October 998, there have been three cases where the pendulum degree has exceeded the standard and forced shutdown. The maximum time is 1.8 1 with the maximum diameter of 321 frame rack vibration. After the shutdown check, it was found that the jacks on the upper frame of the generator were sheared by two jacks. From 12±, three of the upper guide bushes were undercut.
Due to the unstable operation of No. 1 Unit 2, the vibration of the generator on the generator has increased and Yan Zhen has affected the safe and stable operation of the unit. Reliance on adjusting the gap in the upper guide shoe to ensure stable operation of the unit proves to be impossible to solve, and may lead to damage to the upper guide bearing.
3 Unit vibration analysis analysis 3.1 Vibration analysis After repeated analysis and discussion, artificially caused vibration of the unit may be due to the following aspects: 1 No. 2 unit shafting concentricity through the connection bolt and positioning pin The holes are manufactured in the Ding-Yi-made drills, and the precision of the Machining 1 is relatively low, and it is difficult to achieve the field welding with the size valve disc brackets. The 175-diameter human structure will inevitably produce a greater dynamic and static imbalance than the on-site field welding 1 and the North-by-Force technology 52000 42 on the guide bearing tile gap adjustment due to the upper guide shoe support structure adopts an adjustable wedge plate structure, There is a large amount of change in elasticity. In order to eliminate the error caused by using the feeler gauge to adjust the clearance, after calculating the movement amount of the movable wedge according to the ratio of the wedge plate inclination, the upper guide shoe clearance is adjusted by using the method of lifting the upper guide bush and the actual axial position of the set is referenced. The deviation between the center and the theoretical center is tested according to the 43-weight test between the double-sided and 1st-gap and 0.240.301. The counterweight between the shaft and the collar is tested through the variable speed test, and the weight orientation is measured at the 27th magnetic pole radial direction. With the trial weight method, considering the unit's variable speed, changing excitation and variable load, the optimal weight is 3501. Due to the unit's magnetic tension imbalance, but limited to the conditions at that time, using the integrated weight method, after 5 trial weight. In order to achieve both reduce the dynamic imbalance. To offset electromagnetic imbalances. This effectively compensates for the generator's mechanical and energizing unbalanced forces and improves unit operation stability. However, the small-load vibration area still exists due to the hydraulic factors, and this vibration cannot be eliminated by the weight method, so the vibration elimination under the idling condition of the unit is not obvious.
4.22 processing plan 4.2.1 thrust bearing force adjustment and axial processing After analysis, due to the dynamic imbalance of the 2nd unit and the generator upper guide clearance and thrust bearing mirror plate caused by improper adjustment of the rotor stator gap caused by uneven Since the electromechanical imbalance force has the greatest influence, it is necessary to adjust the force of the thrust bearing. After the mirror plate level satisfies the specification requirements, a mechanical rigid disc was set on the axis of the unit, and the broken line point was found at the upper end of the generator. After calculation, the shaft flange surface of the generator was cushioned.
4.2.2 Upper guide bearing clearance adjustment With the No. 1 method, the No. 2 upper guide gap is re-adjusted according to the design requirements.
Force, but the scene can not be balanced test, so that the balance performance is difficult to guarantee. After the unit is installed, it is not proper to use the method of turning the car. That is to say, the elasticity is measured by using an elastic plate. The surface of the plate does not exceed the shoulder and is considered to be the acceptable standard for the axis. Too low = 3.2 Stability test To fully understand the stability of the unit, we The Gansu Electric Power Test and Research Institute used the 00 water machine vibration test and analysis system in October 1998 and February 1998 to perform variable speed, variable excitation, variable load, load rejection, and other conditions on the No. 1 unit in the field. The vibration deflection of the upper guide on the rack under the water guide shaft flange, etc., and the pressure fluctuation of the water pressure in the top cover are compared with the number of shots in the test. The vibration value of the pendulum is increased. Reasons, concluded that there is a dynamic imbalance in the generator unit No. 1 generator rotor; there is a serious electromagnetic imbalance force generator; 3 upper guide bearing bearing clearance is too large; 4 unit shaft line exists folding line.
Generator No. 2 generator rotor has a dynamic imbalance; 2 generators have a large electromagnetic imbalance force; 3 upper guide bearing tile clearance is unreasonable; 4 thrust bearing mirror plate level is out of tolerance, generator upper shaft and rotor centerline There is a polyline.
4 treatment measures and effects 4. No. 4 processing solution 4.1.1 axis to solve No. 1 engine 纟 1 axis line asks. We believe that the + should be used for the impeachment method. Because the method can not determine the axis of the imperial line size. After finding the break line point on the mechanical rigid disc of the unit, add the copper pad to adjust the axis at the joint face of the thrust head and mirror plate and the shaft and rotor joint of the upper end of the generator.
14 Department of peach temperature, carbon wool legs, 4.3 before and after the effect of comparison After the machine and 2 machine vibration analysis, processing data obtained, 1.
5 Conclusions The primary flash of the 1st vibration of the 1st engine of the Huoxia Hydropower Station has an imperative line for the unit axis. There is a large electromagnetic + balance force in the rotor. The reason for the large vibration of Unit 2 is that there is a broken line on the axis of the unit.
The axis of Unit 2 is also processed through the processing of the 14-cylinder unit's axis and the addition of additional equipment, greatly reducing the vibration of the unit. Specially, the No. 2 unit of No. 1 unit is treated with pre-treatment and post-treatment treatment. +z Upper pendulum + y water conductance + z water conductance + r flange + z rack level + z rack level + r lower rack vertical + z is 1 pendulum value Has greatly reduced.
For large hydro-generator units using elastically supported thrust bearing structures, it is not advisable to use elastic disk noon during the inspection phase of the disc brakes during the installation phase. Rigid discs should be used; the adjustment of the upper guide gap is carried out according to the lifting wedge method, and the clearance is calculated by referring to the deviation between the actual axial center and the theoretical axial center, and the tile gap is reasonably distributed.
Responsible editors starlighted on page 37 6 During the national grid 2 anti-combined testing conducted from August 31, 1999 to September 10, 1999, there were no 28 questions in all the measurement automation systems in Gansu grid. It provides a reliable basis for the safe and smooth transition of the system in 2000.
4 Conclusion The stable and high-quality operation plays an important role. It not only involves the stability and development of the power system, but also affects all aspects of society. Therefore, in our future work, we must fully recognize the progress of the computer 2000 arrangement and continue to improve. The implementation of 72 emergency solutions and emergency measures to ensure the smooth transition of the system in 2000.
Solve the problem of scheduling automation in 2000, will be responsible for the security of the power grid compiled by the Yellow River on the 40th page 6 Suggestions to use numerical simulation and other new technologies for Ankang Power Station to increase capacity of the unit to transform the work, choose a good state of flow and efficiency of the turbine, We will fundamentally change the unfavorable conditions of operation conditions of Ankang Power Plant units and maximize the benefits of hydropower. , 1 Ankang Hydropower Station design report. Beijing Survey and Design Institute. 1998.
2 Li Chengjia. Ankang hydropower plant test report. Northwest Electric Power Experimental Institute.
Editor Zhang Jian
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