1 Overview The Daxia Hydropower Station is located in Gansu Province, the upper reaches of the Yellow River. It is the first cascade hydropower station planned and developed by the Longqing River section of the upper reaches of the Yellow River. It is equipped with four 75 river boundary hydroelectric generating units. The turbine model is 2223700, the generator model is 5 corps 756 to 350. The generator is in the form of vertical phase air-cooled semi-umbrella structure. The whole unit shafting turbine turbine runner large shaft generator big shaft generator rotor generator upper shaft The composition of the equal segments.
The total length of the shaft system is 21.48, in which the large shaft length of the turbine is 5.7, the generator shaft length is 5.9, the stator and rotor of the generator are assembled on site, and the stator base is assembled on the site to be welded into a full circle, and the core is laminated and then embedded. line. Rotor sub-rotor center body rotor support co-lobed, auxiliary vertical reinforcement on the construction site, welding stack magnetic pole, mounting magnetic pole, anti-smashing machine upper guide bearing is installed in the center of the frame, the bearing bush adopts adjustable wedge-shaped plate structure to The child frame is provided with 12 shearing jacks to transmit radial force to the foundation, the generator thrust bearing adopts elastic oil tank support knot, and the thrust tile is 12 elastic metal fluorine observation tile water guide bearings adopt self-circulating thin oil lubrication cylinder Tile structure.
2 asks that the upper guide swing is larger than the design allowable value, and the maximum allowable value is 1. The maximum allowable value is 0.3. During this period, the unit was forced to stop for 4 times in February and December of February, 1997. Adjust the tile gap to reduce the swing. The effect is not obvious. The 1å…® unit was put into operation from 1997ä¹6纟. In October 998, the steering degree was severely exceeded 3 times, and it was forced to stop. The maximum time was 1.81. The vibration of the same frame diameter was up to 321 double. After the shutdown checkpoint, it was found that the two jacks of the generator upper frame were cut, from 12±, three tile seats in the upper guide were worn.
Due to the unstable operation of Unit 1 and Unit 2, the vibration of the generator on the upper side of the generator tends to increase, and the strict operation affects the safe and stable operation of the unit. Adjusting the gap between the upper guide bushes to ensure the stable operation of the unit proved to be unable to solve this problem and may cause damage to the upper guide bearing.
Analysis and test of vibration of 3 units 3.1 Analysis of vibration causes After repeated analysis and discussion, the cause of artificially large vibration of the unit may be due to the following aspects: the coaxiality of the shafting of No. 2 unit 2 to connect the bolts and the positioning pins. The hole is made in the manufacturing of Ding Yi, the precision of this processing is low, and it is difficult to achieve the welding of the size disc disc bracket in the field. The diameter of 175 is such a structure that the on-site welding 1 will inevitably produce a large dynamic and static imbalance. The north is controlled by the force technology 52000 42. The bearing pad clearance is adjusted because the upper guide tile support structure adopts an adjustable wedge plate structure. The amount of change in elasticity is large. In order to eliminate the error caused by adjusting the gap with the feeler gauge, after calculating the lifting wedge displacement amount according to the wedge plate inclination ratio, the upper guide bush gap is adjusted by lifting the upper guide bush movable wedge, and the actual axial position of the unit is referred to. The deviation between the center and the theoretical center is measured according to the double-sided 1-gap and 0.240.301. The balance weight test is performed between the shaft axis and the shaft collar. The variable speed test is used to test the radial direction of the weight of the 27th magnetic pole. The trial weighting method, taking into account the unit's variable speed variable excitation variable load and other conditions, the optimal weight is 3501. Because the unit has magnetic tension imbalance, but limited to the conditions at that time, the comprehensive weight method is used, and the test weight is 5 times. In order to achieve both reduce the dynamic imbalance. To offset the electromagnetic imbalance. Thereby, the mechanical and neodymium integrated unbalance force of the generator is effectively compensated, and the running stability of the unit is improved. However, due to the hydraulic factors, the small load vibration zone still exists, and this vibration cannot be eliminated by the counterweight method, so the vibration elimination under the idle condition of the unit is not obvious.
4.22 machine treatment plan 4.2.1 thrust bearing force adjustment and axis processing analysis, due to the dynamic imbalance of the 2nd unit and the generator stator gap and the thrust bearing mirror plate level adjustment caused by the rotor stator air gap is not uniform The electromechanical imbalance force has the greatest influence, so it is necessary to adjust the force of the thrust bearing. After the mirror plate level meets the specification requirements, the machine axis is mechanically rigidly cranked, and the fold line point is found at the upper end shaft of the generator. After calculation, the upper flange end surface of the generator is padded.
4.2.2 The gap adjustment of the upper bearing bush is the same as that of the No. 1 machine, and the gap of the guide bush on the No. 2 machine is re-adjusted according to the design requirements.
Force, and the balance test can not be carried out at the scene, so the dynamic balance performance is difficult to guarantee. It is not appropriate to install the car after the unit is installed, that is, the use of the elastic plate measurement of the mirror surface bounce value is not over the shoulder is considered as the standard of the axis is too low = 3.2 stability test in order to fully grasp the stability of the unit, we Used in the Gansu Electric Power Test and Research Institute, the 00 water machine vibration test and analysis system was tested on the site in October 1998 and February 1998 respectively for the No. 1 and No. 2 units to do the variable speed variable excitation load and load rejection. The vibration swing of the guide on the frame on the lower frame of the water guide large shaft flange and the pulsation of the water pressure of the top cover, after comparing the test batches into the D, the vibration value of the pendulum swing is too large. The reason is that the No. 1 unit 1 generator rotor has a dynamic unbalance; the generator has a serious electromagnetic imbalance force; 3 the upper bearing bearing pad has a large gap; the 4 unit shaft system has a fold line.
There is a dynamic imbalance in the rotor of Unit 2 generator 1; 2 There is a large electromagnetic imbalance force in the generator; 3 The bearing space of the upper guide bearing is unreasonable; 4 The level of the thrust bearing mirror is out of tolerance, the upper shaft of the generator and the center line of the rotor There is a polyline.
4 treatment measures and effects 4. No. machine processing plan 4.1.1 axis processing to solve the No. 1 machine 纟 1 axis system line. We think that + should use the magazine method. Because the modification method can not determine the position of the axis line. After the mechanical rigid disk of the unit is found to find the folding line point, a copper pad is added at the joint surface of the thrust head and the mirror plate and the upper end of the generator shaft and the rotor to adjust the axis.
14 Department of peach temperature, carbon legs, 4.3 before and after treatment compared with the analysis of the machine and 2 machine vibration, the test data, 1.
5 Conclusion The original flash of the vibration of the 1 纟1 of the Huoxia Hydropower Station has a line of prayer for the unit axis. And the rotor has a large electromagnetic + balance force. The reason for the large vibration of Unit 2 is that there is a fold line on the unit axis.
Through the treatment of the 14 units of the axis and the transfer of the assembly, the axis of the No. 2 unit is also treated, which greatly reduces the vibration of the unit. The special design of the No. 1 unit of the No. 1 unit before processing is processed. +z upper swing +y water guide swing +z water guide swing +r flange swing +z upper frame horizontal +z upper frame horizontal +r lower frame vertical +z is 1 guide swing value There is a great reduction.
For large hydro-generator units with elastically supported thrust bearing structures, it is not advisable to use flexible noon when performing the car inspection axis during the installation phase. It is advisable to use rigid cranking; the adjustment of the upper guiding gap is carried out according to the lifting wedge method, and the gap is calculated with reference to the deviation between the actual axial center and the theoretical axial center, and the gap is reasonably distributed.
Responsible editor Starlight was connected to page 37. During the National Grid 2 anti-joint test conducted from August 31 to September 10, 1999, there were no 28 types of questions in all the automation systems of Gansu Power 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 relates to the stability and development of the power system, but also to all aspects of society. Therefore, in our future work, we must fully recognize the progress of the computerized arrangements in 2000 and continue to improve. Implement the 72-question contingency plan and emergency measures to ensure a smooth transition of the system in 2000.
Solve the problem of dispatching automation in 2000, and will be responsible for the safety of the grid. The Yellow River is connected to the 40th page. 6 It is recommended to use the new technology such as numerical simulation to carry out the capacity increase and transformation of Ankang Power Plant, and select the turbine with high flow and high efficiency. It will fundamentally change the unfavorable situation of the operating conditions of the units of Ankang Power Plant 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 Research Institute.
Responsible editor Zhang Jian
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