Diagnosis and prevention of friction and vibration faults of steam turbine generator sets

1 Diagnosis and prevention of friction and vibration faults of steam turbine generator sets China Power International Co., Ltd. North; 100005 Cao Yan North China Electric Power Research Institute Co., Ltd. Bei Ke 1451 Xu Zhijing vibration and the large-axis bending accident caused by it occur when the frictional heat bending effect is introduced. The running speed and critical speed are in 4 different situations. Different phenomena and consequences of frictional vibration occur; different characteristics of slight and severe friction faults; diagnosis and examples of vibration and vibration faults, etc. Finally, it is pointed out how to prevent frictional vibration, that is, in the equipment management structure re-election, maintenance and operation Frictional vibration should be adopted for 1 Guanjian; critical speed; large-axis test wind turbine generator set, especially steam turbine, due to the large change of its structural elevation, and the displacement and deformation of the cylinder expansion, the friction between the static and dynamic components The resulting frictional vibration failure has been repeated. Therefore, the turbine shaft bending accident caused by the steaming has caused great economic losses to the society and the power company itself. Therefore, the diagnosis and prevention of the friction and vibration faults of the steam turbine generator set are increasingly valued by people. In the case of a steam turbine generator set, the thermal bending effect caused by the friction caused by friction is different when the friction is generated in the static and dynamic parts. The temperature on the side of the friction is still on the light friction side, which causes a new unbalanced force on the radial section of the rotor to act on the rotor and cause vibration. This is the thermal bending effect of friction. When the rotor rotates, the eccentricity of the centrifugal force caused by the centrifugal force is the key azimuth. This phase difference or high point lags behind the key lag angle. It can be determined by the formula k. Work violation degree k critical angle violation. Equation 1 can discuss the phase difference. Ding with the working angular velocity allows the rotor to be stationary, that is, in the case of the formula 1, the numerator is zero at this time, so the guard 0 is critically violated in the small hall of the operation hall, and the formula is used to change between the class and the class. That is, the closer the 0 is 90, the closer it is to 90. Therefore, when the rotor is running below the critical speed, the phase difference between the orientation of the eccentricity and the eccentricity of the eccentricity caused by the centrifugal force is 1 The speed deviates from the critical speed and can be approximated as 1 and the old 1 position. If the static and dynamic friction of the turbine occurs, it will easily cause an accident of large shaft bending.

The blade can be seen by Equation 1 when the running speed is equal to the critical speed port. Since the denominator is zero, 1 90! At this time, the dynamic deflection includes the orientation of the vibration caused by it lags behind the eccentricity of the eccentricity 90; 4 when the record rotation speed is much greater than the Linyi rotation violation, that is, by Equation 1, it can be seen that 18 negative values ​​and approaching Zero, that is, D is close to 18 E. If the rotor is elastically bent due to friction, the dynamic deflection is reduced and the friction is removed. According to the formula, the turbine rotor running speed and critical speed are analyzed in four different ways. In the case of the relationship between the orientation of the rotor eccentricity and the orientation of the dynamic burnt caused by it, this is essential for preventing large-axis bending accidents of steam turbines during the overhaul or hot state of the large steam turbines. A fire shaft bending accident occurred. Most of them are due to the improper treatment of friction and vibration. The results of the above discussion can be summarized as follows. When the running speed is low, the phase difference is close to zero, or the acute angle is the critical speed when the operating speed is far. The position and the enthalpy are equal to the enthalpy of the enthalpy at 90; in the region above the critical speed, the phase difference is an obtuse angle, and when the running speed is much higher than the critical speed, it can reach a level close to 180. During the start of the turbine, from low speed to high speed. The phase difference between the 41 critical speeds, the dynamic deflection and the eccentricity is changed by the acute angle 9 and the blunt 180, which is the process from the same phase to the inversion.

The following is combined, rubbing the vibration, and the concept is specifically described.

The frictional vibration of the steam turbine at the lower than the critical speed increases the centrifugal force of the turbine rotation. If the dynamic deflection caused by the poor dynamic balance of the rotor or the original thermal bending before the unit starts, the dynamic deflection exceeds the reserve of the turbine. When the radial gap of a certain direction disappears, the friction will occur between the steam seals or the baffle blocks, and the rotor wave will gradually accumulate heat according to the parts, thereby producing thermal deformation, which is an acute angle due to the phase difference, that is, The bending orientation caused by thermal deformation and the original eccentricity of the rotor are basically the same, and the eccentricity causes the thermal deformation caused by the friction to increase the eccentricity. Such a vicious cycle will cause the friction of the static and dynamic parts to be intensified in a short period of time, and the vibration condition of the unit will deteriorate sharply, and finally the permanent bending of the rotor will be formed. Due to the large-axis bending accident caused by frictional vibration, most of them occur below the critical speed. The reason is the frictional vibration that occurs at the critical speed. In general, the dynamic deflection of the rotor at the critical speed is several times that of the working speed. The dynamic deflection of the rotor is especially for new or overhauled units when passing the critical speed of the transfer. It is easy to occur in the static and dynamic parts. Therefore, when the casing 1 is started, the critical speed of the shaft system should be passed at a faster lifting speed to avoid stopping at the critical speed of the rotor. At the critical speed, the dynamic burning degree of the rotor lags behind the eccentricity of the rotor 90. The current 1 indicates that the initial deflection force of the friction process at this time is delayed by 9 degrees. If friction occurs, it is inevitable. Starting from a good point in the 5 direction, and generating thermal deformation at a good point, a new eccentricity is formed in the direction of the 10,000. The eccentricity of the eccentricity 4 after the eccentricity is 4 lags behind 1 90, the friction point is transferred from the 5 direction to the direction. At the 5th, due to the thermal deformation caused by friction, a new eccentricity is formed, and it is found that the vibration vector is rotated by the rotation side of the reverse turbine. This phenomenon is the characteristic of frictional vibration. This feature constitutes the full-cycle friction of the rotor, indicating that the rotor bending due to friction at the critical speed is a temporary thermal bending under normal conditions. Therefore, with a faster mention, the speed through the critical speed of the conversion, no need to buckle. The heart will turn to a lesser person. This is the case where the motor vibration 4 occurs at the critical speed of the trader. The phase difference is an obtuse angle. Moreover, the farther away from the critical speed of the engine, the closer it is to the rotor. The closer to 18, the frictional vibration occurs, and a very favorable situation arises. Because the direction of dynamic combustion and the direction of eccentricity are close to the opposite direction, the heat generated by friction The deformation has a tendency to offset the original unsteadyness, or the deformation caused by friction has a tendency to retreat friction and when it is lower than the critical speed, the friction caused by the friction of the friction is ambiguous. The moving part is slightly rubbed, even in the rotor end of the steam seal, there is a squeaking spark pool, and the speed is increased rapidly, to the working speed, which is 1; the permanent mountain that will turn the mountain will also increase the speed of the shaft vibration. Characteristics of Capricorn Vibration The turbine rotor and generator of the modern large-scale steam turbine generator set are all flexible rotors, and the phase difference between the dynamic enthalpy of the rotational speed 7 and the eccentricity is an obtuse angle. At this time, if the original unbalance amount of the rotor is small, it is much smaller than the rotational imbalance component generated by the friction. The characteristics of the frictional vibration are the vibration vector in the reverse rotation direction and the amplitude change with time. The axis vibration vector of a certain 325 river boundary unit is measured at 21! Rotated 360 inside! When the vibration vector is at a certain phase angle, the thermal eccentricity caused by friction and the original mass eccentricity of the rotor coincide with each other, and the amplitude is the largest; and at a difference of about 180, the opposite direction occurs, and the amplitude is the smallest at the operating speed.撺 If the original unbalanced quantity and the rotational unbalance component due to friction are approximately equal, then the new unbalanced quantity of the two is changed from the maximum to the minimum, and the phase only changes by 180. If the beginning is not, the 玷 玷 玷 尸 尸 檫The rotation is unbalanced. Then the size and phase of the new unbalanced after the synthesis are not available in the above 3 typical cases.

For the original is not, the balance; 51 is the rotation caused by the friction is not measured; 004 is the content of the corpse 1 and the corpse 4.

Some nonlinear effects may also occur with a small amount of frequency division and frequency doubling. The amplitude and phase of the vibration of the 1 frequency component have fluctuation characteristics. For the slight frictional vibration occurring at the critical speed and above, the vibration phase is significantly reversed from the rotor. Rotation in the direction of rotation, even up to 36 weeks; amplitude changes periodically with time. When the friction is severe, the amplitude and phase of the vibration no longer fluctuate.

The vibration phase is basically the same, and the amplitude will increase sharply. It will be a divergent stop. The vibration at the critical speed will be greater than the normal speed. After the friction vibration occurs, stop to the cranking state and immediately check the sway pit of the rotor. It is much larger than the normal value, and is generally 10 levels. If it is elastic hot bending, the normal sway value of the rotor can be restored after the vehicle section time.

3 Example of frictional vibration and falling The friction of the static and dynamic parts under the working speed is strictly determined to the extent that the deformation caused by the local thermal expansion of the friction part is much larger than the dynamic deflection caused by the eccentricity of the original bending of the rotor. This deformation is much larger than the dynamic and static partial clearance value. Therefore, when severe local friction occurs, the newly generated dynamic burning degree only has the tendency to avoid friction, but the original friction point is still not open, so the vibration phase at this time is basically unchanged. The amplitude gradually increases, and the divergent trend flashes. This type of friction vibration occurs after the rotor brake is stopped, and the + must be excessively worried that the rotor will be permanently bent. The friction vibration of the Taiwan 100 Hejia steam turbine occurred during the starting process, and the wear of the most severe wear parts after the cargo was calculated. When the fault occurred, the total deformation of the static and dynamic parts of the friction part was as high as 4.3. When the 3004 boundary unit is tested for electrical test, the friction between the low pressure steam seal and the oil block of the bearing housing causes the friction vibration, the amplitude of the 发 is divergent, and the change of the position reverse steering does not exceed 20 = only at that time The amplitude is as large as the limit value, that is, the measure of the brake stop. 2 The characteristics of the frictional vibration are combined. For the analysis of the frictional vibration generated under different conditions, the following characteristics of the dynamic and static friction fault can be summarized. The diagnosis of frictional vibration is crucial.

3.1 Frictional vibration occurring below the critical speed of the rotor. The 1st cylinder double-exhaust steam 200 river boundary unit was in normal shutdown maintenance, the cylinder temperature slipped to about 35 after the shutdown idling process, because the No. 2 bearing 庵 movement was not smooth, When the middle cylinder contracts, the front end of the bearing housing is tilted up, and the gap between the lower shaft seals of the jade cylinder disappears to cause frictional vibration. Near the high-speed rotor step critical speed of about 17007, the online vibration monitor 300 and 0 PCT 2000 have reflected that the shaft vibration is not normal, but at that time failed to cause the operating duty personnel to pay attention to the unit has not been stationary, failed to check the rotor in the cranking state The sway, that is, the steam is quickly cooled, and the unit speed is maintained at 500 or so. Later, when the operator found that the speed was 1攘 and the large speed control valve was ready to be opened, the frictional torque of the rotor was too large and stationary. The subsequent process of measuring the rotor and the measurement of the rotor yaw value confirmed that the high-pressure rotor had a permanent bending and cylinder inspection, and the permanent bending value of the front axle seal of the high-pressure rotor reached a record 1.8.

A double-cylinder double-exhaust steam 300 river boundary unit, which has just been put into operation for about half a year, during the hot start process, the steam temperature in front of the high-pressure main steam valve and the reheat main steam valve of the steam turbine is higher than that of the boiler side. The steam temperature is about 35, and 25, respectively, and the rotor sway is checked during the cranking process after the 3300 is stopped. From +, 3, to 0.03, it is confirmed that the high and medium pressure rotor has been permanently bent. Excavation inspection, the permanent bending value of the rotor at the shaft seal between the high and medium pressures is 61. As can be seen from the above example, the frictional vibration 1 at low speed will generate a new unbalance force due to thermal bending, so the vibration, Li, Le Li 髹子卿 厉逢9, large, must be treated as a direct axis. This more intuitively confirms the separation of the severity of the frictional vibration below the critical speed. 3.2 The frictional vibration occurs at the working speed due to the large steam turbine generator set. Turned into a burnt rotor. Therefore, all the vibrations occurring at this time are higher than the critical speed. The vibration can be seen from the examples listed above. The slight friction vibration at the working speed is not harmful. Repeated several times to stop the process can be eliminated at the working speed. Serious frictional vibrations that occur underneath must be repaired before they can be completely resolved. The friction vibration of a 300 River boundary unit introduced during the trial operation was examined by the low pressure cylinder. It was found that the radial clearance of the local steam seal disappeared due to the cylinder offset, and the static friction occurred in the static and dynamic parts. The baffle has ground the shaft surface out of the deep groove. As a temporary measure, the manufacturer increased the radial clearance of the diaphragm seal to a radial direction of 1.21.8 and improved the oil and assembly structure to eliminate the frictional vibration.

4 Prevention of Friction and Vibration Faults The above is a detailed discussion of the examples of the vibration faults generated by the friction and vibration of the steam turbine generator set. How to prevent the frictional vibration, that is, what countermeasures should be taken in the equipment management structure to change the inspection and maintenance and operation, etc. In order to prevent the occurrence of frictional vibration, we must first analyze the weaknesses of the unit structure 1, and adopt effective structural improvement along the application and maintenance measures. The main aspects are as follows: 4.1 Modern structure of the steam seal structure and material The diaphragm seal and the end shaft seal of the steam turbine adopt an elastic steam seal. The material of the steam seal tooth is 1 plus or 5 in the high temperature section, and the low temperature section is called the 8 yellow 14 according to the simulation test conclusion of a certain department. For a cumbersome pearlite-like material, if it is only called a yellow force on the steam seal arc, it is about 504. At this time, when the steam seal tooth and the shaft are rubbed, the heating amount to the shaft is not large, and the temperature is about 200300. In the rated load, the high 1 card steam seal arc is affected by the vapor pressure difference between the inside and the outside. The groove of the steam seal is small and the groove is cut out. The groove is relatively deep to 68 brass, because its melting point is low 93, the hardness is not high. 55. When the steam seal teeth and the shaft are rubbed, the teeth are quickly worn and adhered to the shaft surface to lubricate, so the wear amount of the shaft is greatly reduced. If a spring force of 50,500 is applied to each block of the steam seal, the maximum temperature at which the shaft is heated by friction is only the conclusion of the above test. The existing steam seal structure should cancel the steam force acting on the back of the arc block; if the back of the arc block is made of a leaf spring, it is recommended to use the screw yellow, and the arc of the arc should be evenly sealed by the secondary elastic force; the gap should be increased to 2.51. The above is the steam seal arc block neck wide 1 oil gap should be increased to 0.5 瞧 application temperature section of the steam seal tooth material is recommended to be changed to 015 river, ferrite material, the hardness of this material is relatively low. 86. is 89.8, while in friction After heat generation, it will not be hardened 950. The hardness after oil quenching is 55.557.0. The radial clearance of the steam seal can be as small as 0 381. The steam seal tooth material used for the low temperature section without damage to the journal is included. The use of Sun Lead Chai brass 4.2 bearing box and cylinder expansion bearing box to move the cylinder to cause expansion or contraction of the cylinder is blocked. The deformation or offset of the cylinder will cause the radial clearance of the flow passage of the turbine to change, and the friction of the static and dynamic parts will cause such a problem. The unit should be improved in the following aspects to improve the lubrication between the bottom of the bearing housing and the platen to reduce the friction during movement. At present, the effective method is to use a 0-man alloy to make a slider, or to insert a graphite block on a steel or a prayer iron slider to improve the structure of the push-pull device, and to make the thrust point shift. Thereby, the turning moment when the movement of the bearing housing is hindered is reduced and the cross pin of the cat claw is no longer the bearing point at the time of pushing and pulling.

Adding an auxiliary support on the cylinder to reduce the pressure on the bearing housing to reduce the leakage of the shaft seal to prevent the bottom of the bearing housing from slipping at the bottom. Consider changing the material of the stringer or hardening the surface so as not to be oxidized by high temperature. The card flow 4.3 test dynamic balance overhaul to test the dynamic balance of the rotor, focusing on reducing the critical speed, the shaft vibration water should be under various speeds and loads, the unit's vibration conditions are good, 4.4 improved insulation materials used Good performance cylinder insulation materials, such as aluminum silicate fiber felt. And improve the insulation construction process to ensure that the insulation material is close to the cylinder, without the phenomenon of disengagement of voids or faults. 4.5 Ensure that the installation accuracy should ensure the bending value of the coupling value of each rotor, especially after the connection of the wheel. Qualified value 4.6 Adjust the gap of the upstream part of the gap turbine to meet the standard requirements. Accurate adjustment and measurement, and reduce the 纟1 combined with the standard gap standard should be arranged in different sections of the cross-section of the steam seal gap in the high and medium pressure rotor if the fulcrum support. Then, the influence of the rotor static deflection on the radial clearance of the through-flow portion after the connection of the opposite wheel should be considered.

4.7 Fine-tuning the rotor center Strictly adhere to the quality standard Strictly follow the requirements of the gun repair process specification to determine the rotor core behavior, determine the change of the bearing seat elevation in the hot state, and should adjust the clearance of each bearing when performing the cold state center adjustment of the unit. Lige Tiewujin and other standards should be standard.

4.8 Oil block bearing housing oil block should be changed to a structure that is easy to install and adjust.

The oil block gap should conform to the standard oil block material and the tip shape should meet the paper requirements. 4.9 The sliding pin system should be carefully cleaned during the overhaul. Check the sliding pin system to check the positioning and guiding parts between the inner and outer cylinders to eliminate the deformation and other faults to ensure The flow part of the gap is unchanged 4.10 Perfected the complete instrument of the turbine generator vibration online monitor, including the vibration measurement and shaft vibration measurement of each main bearing, and the subsequent vibration analysis of the vibration analysis system. The system makes the data should be less than the trend of the trend analysis spectrum analysis, the baud limit report and the printing system and other functions in the cylinder cat claws, the installation of cylinder lateral expansion indicators to monitor the left and right side of the cylinder expansion is Qiaojun 4 in the turbine An axle-type absolute shaft vibration measuring device can be installed near each bearing to monitor the bending enthalpy of each rotor more intuitively before and after the unit is started. 4. The vibration protection of the unit when starting the unit 4.12 Strictly observe the operating procedures. When operating the operating procedures, when the vibration exceeds the standard phenomenon, especially when the vibration below the critical threshold exceeds the standard, it should be immediately braked. Break the vacuum. It is forbidden to connect the speed-reduction machine to page 35. It is necessary to pay attention to the scope of the transformation as soon as possible. This will directly affect the design and supply of the hardware side, and the final confirmation of the software side configuration. If the transformation involves the change of the person, The end of the project will lead to the delay of the construction period. If the card is dead, it will be a large amount, plus the daily workload, which will cause the engineers to be extremely exhausted, prone to errors or omissions. Printed a hidden danger.

3.4 The signing of official documents, whether it is to write a business contract or a technical agreement, or to sign the minutes of the meeting. Pay attention to the accuracy of the words. Avoid embarrassment.

The ambiguity has caused the parties to make arrangements for the progress control of the project. All parties must confirm the progress of the project according to their actual situation and then strictly enforce it.

3.5 Management of Data Each project must have a dedicated person responsible for managing all engineering materials, as well as a list of information to be queried. These materials include the data of the parties to the fax attachments of each meeting minutes of the technical contract of the engineering contract additional contract technical agreement. Project implementation progress hardware configuration is called 5 soft 1 design specification system test outline system test report operation manual subsystem sub-programger debugger, system sub-program debug report, design change record 1 each system software catalog and program A kind of hardware manual training plan, various training materials, engineering acceptance report, unfinished project memorandum and so on.

4 Conclusions Each 0, the transformation project is a complex and rigorous system project that requires multi-party cooperation. Only through the perfect management and cooperation of all parties, can we successfully complete the implementation of several transformation projects on time and in time. The length is short, the units are large and small, and the scope of the transformation is also wide and narrow. The above project implementation process is summarized, which basically meets the old unit 005 renovation project in North China. All the above completed renovation projects have passed the 1681 type operation on time or in advance. All the indicators are in line with the requirements of the power plant tenders. In addition to the impact of the individual equipment on the automatic investment of the old equipment, it is well received by the users of the power plants. This shows that our retrofit design is correct and management is scientifically feasible. The old unit transformation has improved the stability of the unit operation, improved the automation of power plant management and maintenance, and reduced the power generation cost. Improve the working conditions, but also bring huge economic benefits to the power plant. Received date 2001 YE 919 quality is the guarantee for the survival of enterprises!

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