I. INTRODUCTION For the safe operation of steam turbine generator sets, the Thermal Power Research Institute of the Ministry of Electric Power successfully developed the "ZJZ-1", "ZJZ-2" and "ZJZ-3" turbine generator set vibration monitoring and fault diagnosis. The system and the "NBZJZ-1", "NBZJZ-2" and "NBZJZ-3" portable multi-channel vibration data acquisition and analysis systems have been listed by the State Council as key scientific and technological achievements during the "Eighth Five-Year Plan" period. Now it has been used on more than 100 turbine generator sets. The system has good stability and reliability, and users can use it with confidence. It is helpful to monitor and handle the vibration of various turbine generators on site. In order to more easily diagnose and deal with the various vibrations that occur at the remote power plant in a timely manner, on this basis, the "Remote Turbine Generator Set Vibration Analysis and Fault Diagnosis Center" was developed. The vibration fault information of the power plant unit is timely transmitted to the vibration fault diagnosis center of the Thermal Power Research Institute of the Ministry of Electric Power through remote communication. The center quickly analyzes the vibration data and returns its results and processing opinions to the power plant so that effective measures can be taken to eliminate vibration faults in time. Avoid expansion of vibration and serious accidents. This greatly improves unit availability, reduces maintenance costs, prolongs equipment life, etc., and provides effective monitoring means for the periodic preventive maintenance to be replaced by a prescriptive maintenance system. This is of great significance to improving the economic and social benefits of the company.
Now that the remote turbine generator vibration fault diagnosis center is operating, several examples of vibration fault diagnosis are briefly described below.
Second, application examples 1. Remote vibration analysis and fault diagnosis of Unit 1 in Shuangliao Power Plant 1.1 Vibration fault diagnosis of No. 1 unit in Shuangliao Power Plant on December 22, 1996 300MW unit produced by No. 1 unit of Shuangliao Power Plant in Harbin, shaft structure shown in Fig. 1 .
After the second overhaul on December 22, 1996, the vibration was increased with time and the alarm value exceeded the time when the engine was started for the fifth time at 2000 r/min. The unit was installed with a ZJZ-2 steam turbine manufactured by the Thermal Power Research Institute of the Ministry of Electric Power. Generator set vibration monitoring and fault diagnosis system. The "ZJZ-2 type" system preserves the development of the entire vibration fault and performs "vibration vibration diagnosis." However, at the time, the site personnel were not very clear about the location of the friction. For this purpose, the relevant vibration data was transmitted via remote communication. The analysis results are shown in Figure 2-3. From Figure 2-3, it can be seen that when the 5th and 6th axes are at 2000r/min, the vibration is increasing, and it is considered that radial dynamic and static friction occurs in the generator rotor. After inspecting the generator, it was found that the rubber skin and the large shaft of the generator air gap in the air gap of the generator core were rubbed off, and the rubber skin was cut off and the vibration returned to normal after restart.
1.2 November 26, 1997 Shuangliao Power Plant No. 1 remote vibration analysis and fault diagnosis November 26, 1997 16:00-November 27, 1997 8:00 Shuangliao Power Plant No. 1 machine has two times of vibration Excessive fault. Shuangliao Power Plant timely informed the Thermal Power Research Institute of the Ministry of Electric Power that the relevant data was transmitted to the Thermal Power Research Institute of the Ministry of Electric Power in time through long-distance communication. The data analysis and vibration fault diagnosis results are as follows:
Figure 4 shows the vibration trend of Unit 1 in Shuangliao Power Plant on November 27, 1997 from 16:00 to 1997 at 11:00 on the 27th. Figure 5 shows the vibration waveform, frequency spectrum, and 3D spectrum of the No. 2 Shuangliao Power Plant at 5:30 on November 27, 997. It can be seen from Fig. 4 that the load of No. 1 unit of Shuangliao Power Plant is about 300 MW from about 16:15 pm on November 26, 1997 to about 17:15, but the shafting vibration has great changes. The vibration of No. 3 tile gradually increases from 32μm to 65μm. The Y-direction vibration of No. 2 axis gradually decreases from 42μm to 22μm, the Y-direction vibration of No. 3 axis gradually increases from 80μm to 180μm, and the Y-direction vibration of No. 4 axis gradually increases from 30μm to 117μm.
At around 17:15-17:45 in the afternoon of November 26, 1997, the load of Unit 1 of Shuangliao Power Plant remained unchanged at about 300MW, but the vibration of the shafting system was greatly changed. The vibration of No. 3 tile gradually decreased from 65μm to 30μm. The vibration of No. 2 shaft gradually increased from 22μm to 38μm. The Y-direction vibration of No. 3 axis gradually decreased from 180μm to 80μm. The Y-direction vibration of No. 4 axis gradually decreased from 117μm to 22μm. To the original vibration level.
At around 21:00 on the night of November 26, 1997, No. 1 unit of Shuangliao Power Plant began to reduce the load, and it was reduced from 300MW to 200MW at 22:30, and then remained at 200MW. The load began to increase again around 3:20 am on November 27, 1997, and the load rose to 270 MW around 4:50. At this time, vibrations of the 3rd, 6th, 2nd, 3rd, and 4th axis in the Y direction gradually increased. The vibration of the 3rd watt gradually increased from 38μm to 65μm. The vibration of the 6th watt gradually increased from 28μm to 31μm. 2 The Y-axis vibration gradually increases from 30 μm to 88 μm, the Y-axis vibration increases gradually from 82 μm to 230 μm, and the Y-direction vibration increases gradually from 25 μm to 230 μm. At this time, the No. 1 unit of Shuangliao Power Plant reduced the load to 200MW, and after running for about 35 minutes, No. 3 Watt vibration, and No. 6 Watt vibration, No. 2, No. 3, No. 4 axis Y direction vibration gradually returned to normal values.
From Fig. 5, it can be seen that when the vibration increases, the spectral components in the Y-direction vibrations of the No. 3, No. 3, and No. 4 axes are mainly 1X.
From the above analysis, it can be seen that each vibration change gradually increases, then gradually decreases and then returns to normal. The vibration spectrum components are mainly 1x components, and the vibration is frictional vibration. The friction shaft section is a low-pressure rotor. There are two possible frictional parts, one may be the shaft-segment seal or the bulkhead-seal of the low-pressure rotor, and the other may be the friction at the top-steam seal of the low-pressure rotor blade. When the contact is wiped off due to friction, the vibration returns to normal.
1.3 On Jan. 7, 1998, the No. 1 unit of Shuangliao Power Plant started to vibrate with high vibration. Remote fault diagnosis Vibration of the No. 1 unit of Shuangliao Power Plant exceeded the limit on January 7, 1998. In Figure 6. It can be seen from Fig. 6 that at 300r/min, the 3-W vertical, 3-axis X and 3-axis Y-direction vibrations increase with time; at the time of deceleration, the over-critical vibration of each measurement point increases significantly. The maximum vibration at 3 watts was 230 μm at the time of speed reduction, and the maximum vibrations of the 3-axis X and 3-axis Y were 240 μm and 420 μm. From the figure, it can be seen that friction occurs in the low-pressure rotor. There are two possible locations for the friction. One is only in the shaft seal, the partition seal, and the other at the top of the blade and the spacer. This in turn causes radial and static friction between the shaft seal and the diaphragm seal.
After the shutdown and demolition inspection, it was found that the top shroud of the last stage of the low-pressure rotor had a friction at the top shroud, and the shroud of the generator side was removed afterwards.
1.4 January 19, 1998 Shuangliao power plant No. 1 remote vibration fault diagnosis of the machine on January 19, 1998 Shuangliao power plant No. 1 machine vibration overrun. The power plant contacted us in a timely manner and transmitted the vibration data to the Thermal Engineering Institute through remote communication. The analysis results are shown in FIG.
According to the vibration data from the remote communication, we analyzed the vibration variation and frequency spectrum characteristics of the No. 1 unit of the Shuangliao Power Plant during the first month of January. The vibration increase was from 240 MW to 5:44 at 5:00 on the 19th. The 260 MW load condition is mainly reflected in No. 3 and No. 4 bearings. Among them, bearing No. 3 bearing vibration increased from about 30μm to a maximum of about 60μm. Bearing No. 3 bearing X and Y axis vibrations increased from 70μ and 65tμ to about 150μm and 90μm respectively. No. 4 bearing Y-axis vibration increased from about 30μm. As large as 150μm or so. The vibration value is the maximum when the load condition is around 250 Mw, and then the vibration gradually decreases as the load increases. After 6:00, the unit vibration returned to normal. In addition, when the vibration increased, No. 3 Watt vibration, the vibration frequency spectrum of No. 3 and No. 4 bearing shaft vibration was dominated by the fundamental frequency component (1X).
From the analysis, it can be seen that the vibration variation of each bearing first gradually increases, then gradually decreases and returns to normal, and the vibration spectrum component is mainly 1X component. Therefore, the vibration is judged as frictional vibration, which may be the low pressure during the loading process. Rotor hits and touches the rotor. There are two possible positions where dynamic and static friction occur. One is at the steam seal, and the other may be rubbing at the top of the blade and the bulkhead, the shaft seal or the bulkhead.
Shuangliao Power Plant once in January 1998, the shutdown inspection found that the last stage of the low-voltage with surrounding friction, and some of the shroud rivets were swept away, which further shows that the above diagnosis is correct.
2. Remote vibration analysis and diagnosis of Unit X in Yibin Power Generation Plant The Yibin Power Generation Plant No. X was an Eastern 200MW unit with vibration overrun at startup. The relevant data is collected through remote communications and the analysis results are shown in Figure 8-10.
(1) It can be seen from Fig. 8 that the vibration changes with time when the unit load is constant. On July 4, 1997, from 8:00 to 8:45, the five- and six-watt vibrations increased continuously, and the increase in vibration was caused by friction.
(2) Figures 9 and 10 show the 5-watt and 6-watt vibration Bode plots for several times during July 2, 1997 and July 4, 1997. From Fig. 9 and Fig. 10, it can be seen that the vibration at the deceleration over the critical speed is greater than the vibration at the speed up over the critical speed. This is due to the fact that the shaft is bent due to friction, which changes the balance of the shaft system.
(3) From the above analysis, it is shown that the vibration change is caused by friction. From the analysis of the vibration change trend, the friction causes friction between the shaft seal and the shaft.
The power plant demolition inspection on July 6 found signs of shaft seal friction. After the shaft seal gap is enlarged and the control operation is performed, the shaft seal is wiped off and a small amount of imbalance is added to the low-rotation pair. The vibration problem is solved.
3. Remote vibration analysis and fault diagnosis of No. 5 unit of Qingzhen Power Plant The Qingzhen Power Plant No. 5 machine 50MW unit, when started on April 21, 1997, the vibration exceeded the limit. The relevant vibration data stored by the ZJZ-1 system was sent to the Vibration Research Center of the Thermal Engineering Institute through remote communication. The results of the vibration analysis of the remote communication data are not shown in Figure 11 and Table 1-2. The analysis results are as follows:
(1) When started on April 21, 1997, the vibration exceeded the limit when the rotational speed reached around 3000r/min. It can be seen from the vibration values ​​of the 1-watt level (1 watt-) pass frequency, 2 watts vertical (2 watts +), and 2 watts horizontal (2 watts) pass frequency when the No. 5 engine of Qingzhen Power Plant is increasing in speed in Fig.11. When the rotation speed is 3000 r/min), the 1 watt level (1 watt-) vibration increases by about 18 μm, and the 2 watts vertical (2 watts +) and 2 watt levels (2 watts -) vibrations increase by 50 μm and 35 μm, respectively.
It can be seen from the changes in vibration of Fig. 11 that the speed of overshooting is significantly increased. From the above, it can be seen that the reason for the vibration overrun at the start of April 21 is due to radial friction. .
(2) Table 1 and Table 2 show the vibration values ​​at the start of April 21, 1997. It can also be seen from Table 1 and Table 2 that the vibration increases significantly at a given speed, which is caused by radial friction.
After the unit was shut down, it was started again by the low-speed rolling stock. During the speeding up process, the vibration does not increase with time, but the 2 watt vibration in the vertical direction is still too large.
4. Qingzhen Power Plant No. 5 unit long-distance vibration balance treatment Since No. 5 unit is full load, 2 watt vibration is still too large, the power plant wants to make dynamic balance to reduce its vibration. According to the calculation of the vibration data of the long-distance communication, it is given from Xi'an that the weight of the final impeller is 336 grams and the direction is 180. After the power plant was accentuated, the 2 watt vibration was reduced, which solved the problem of vibration of the No. 5 machine and reduced the downtime for at least 2-3 days. The direct economic and social benefits were obvious.
5. The remote vibration fault diagnosis of No. 2 unit of Pucheng Power Plant Pudong Power Plant No. 2 was Romania's 330MW unit, which was started at the end of December 1997. At a 1500 r/min moderate speed warm-up, the generator's rear shim vibration slowly increased over time from 15 μm to 70 μm. From the analysis of the NDZJZ-2 type system produced by the Thermal Power Institute, it can be seen that the vibration component is mainly the 3 times frequency component, which is excluded as the possibility of dynamic or static friction or Mova vibration failure, and the analysis is structural resonance. After the scene changed the rotational speed from 1500r/min to 1800r/min, the 6-watt vibration immediately decreased, and the 3X component gradually disappeared. This reduces one downtime.
III. Analysis of Economic Benefits and Social Benefits From the above application examples, the turbine vibration monitoring and fault diagnosis system manufactured by the Thermal Power Institute of the Ministry of Electric Power was installed in each unit of the power plant, and a remote vibration analysis and fault diagnosis center was established. With obvious economic and social benefits.
1. The existence and development of faults in a timely manner can be promptly announced so that maintenance personnel can formulate maintenance schedules in a timely manner, shorten maintenance time, reduce maintenance costs, and avoid blindly making maintenance projects. For example: When the No. 1 unit of Shuangliao Power Plant suffered from a vibration failure, all the information was saved, so that it was clearly known that the faulty shaft segment was a low-pressure rotor. Only check the low pressure rotor at the time of shutdown, and accurately find the friction of the last blade shroud, reduce the blind stop 2 times, and reduce the inspection cycle 2-3 days. Its direct economic benefits nearly 500 million.
2. Timely capture of fault information, reducing the repeated start-stop test for finding the cause of vibration of the unit. Improve troubleshooting accuracy. For example, the friction of the No. 1 unit of Shuangliao Power Plant started on December 26, 1996. The system captures the entire development process of the fault and determines the position of the friction in the generator through the remote fault diagnosis center. It quickly eliminates vibration, reduces start-up and shut-down at least 1-2 times, generates power 2-3 days in advance, and has direct economic benefits of more than 300 million yuan. .
3. Reduce the number of start and stop times of the unit when seeking balance.
For example, the dynamic balance of No. 5 engine in Qingzhen Power Plant obtains vibration data of the unit through long-distance communication, and gives weighted blocks in Xi’an to reduce downtime by 2-3 days. The direct economic benefit is nearly RMB 1 million.
(Editor's Note: Due to limited space, the drawings and tables will be omitted. Please contact the Thermal Institute Huang Xiuzhu if necessary)
Now that the remote turbine generator vibration fault diagnosis center is operating, several examples of vibration fault diagnosis are briefly described below.
Second, application examples 1. Remote vibration analysis and fault diagnosis of Unit 1 in Shuangliao Power Plant 1.1 Vibration fault diagnosis of No. 1 unit in Shuangliao Power Plant on December 22, 1996 300MW unit produced by No. 1 unit of Shuangliao Power Plant in Harbin, shaft structure shown in Fig. 1 .
After the second overhaul on December 22, 1996, the vibration was increased with time and the alarm value exceeded the time when the engine was started for the fifth time at 2000 r/min. The unit was installed with a ZJZ-2 steam turbine manufactured by the Thermal Power Research Institute of the Ministry of Electric Power. Generator set vibration monitoring and fault diagnosis system. The "ZJZ-2 type" system preserves the development of the entire vibration fault and performs "vibration vibration diagnosis." However, at the time, the site personnel were not very clear about the location of the friction. For this purpose, the relevant vibration data was transmitted via remote communication. The analysis results are shown in Figure 2-3. From Figure 2-3, it can be seen that when the 5th and 6th axes are at 2000r/min, the vibration is increasing, and it is considered that radial dynamic and static friction occurs in the generator rotor. After inspecting the generator, it was found that the rubber skin and the large shaft of the generator air gap in the air gap of the generator core were rubbed off, and the rubber skin was cut off and the vibration returned to normal after restart.
1.2 November 26, 1997 Shuangliao Power Plant No. 1 remote vibration analysis and fault diagnosis November 26, 1997 16:00-November 27, 1997 8:00 Shuangliao Power Plant No. 1 machine has two times of vibration Excessive fault. Shuangliao Power Plant timely informed the Thermal Power Research Institute of the Ministry of Electric Power that the relevant data was transmitted to the Thermal Power Research Institute of the Ministry of Electric Power in time through long-distance communication. The data analysis and vibration fault diagnosis results are as follows:
Figure 4 shows the vibration trend of Unit 1 in Shuangliao Power Plant on November 27, 1997 from 16:00 to 1997 at 11:00 on the 27th. Figure 5 shows the vibration waveform, frequency spectrum, and 3D spectrum of the No. 2 Shuangliao Power Plant at 5:30 on November 27, 997. It can be seen from Fig. 4 that the load of No. 1 unit of Shuangliao Power Plant is about 300 MW from about 16:15 pm on November 26, 1997 to about 17:15, but the shafting vibration has great changes. The vibration of No. 3 tile gradually increases from 32μm to 65μm. The Y-direction vibration of No. 2 axis gradually decreases from 42μm to 22μm, the Y-direction vibration of No. 3 axis gradually increases from 80μm to 180μm, and the Y-direction vibration of No. 4 axis gradually increases from 30μm to 117μm.
At around 17:15-17:45 in the afternoon of November 26, 1997, the load of Unit 1 of Shuangliao Power Plant remained unchanged at about 300MW, but the vibration of the shafting system was greatly changed. The vibration of No. 3 tile gradually decreased from 65μm to 30μm. The vibration of No. 2 shaft gradually increased from 22μm to 38μm. The Y-direction vibration of No. 3 axis gradually decreased from 180μm to 80μm. The Y-direction vibration of No. 4 axis gradually decreased from 117μm to 22μm. To the original vibration level.
At around 21:00 on the night of November 26, 1997, No. 1 unit of Shuangliao Power Plant began to reduce the load, and it was reduced from 300MW to 200MW at 22:30, and then remained at 200MW. The load began to increase again around 3:20 am on November 27, 1997, and the load rose to 270 MW around 4:50. At this time, vibrations of the 3rd, 6th, 2nd, 3rd, and 4th axis in the Y direction gradually increased. The vibration of the 3rd watt gradually increased from 38μm to 65μm. The vibration of the 6th watt gradually increased from 28μm to 31μm. 2 The Y-axis vibration gradually increases from 30 μm to 88 μm, the Y-axis vibration increases gradually from 82 μm to 230 μm, and the Y-direction vibration increases gradually from 25 μm to 230 μm. At this time, the No. 1 unit of Shuangliao Power Plant reduced the load to 200MW, and after running for about 35 minutes, No. 3 Watt vibration, and No. 6 Watt vibration, No. 2, No. 3, No. 4 axis Y direction vibration gradually returned to normal values.
From Fig. 5, it can be seen that when the vibration increases, the spectral components in the Y-direction vibrations of the No. 3, No. 3, and No. 4 axes are mainly 1X.
From the above analysis, it can be seen that each vibration change gradually increases, then gradually decreases and then returns to normal. The vibration spectrum components are mainly 1x components, and the vibration is frictional vibration. The friction shaft section is a low-pressure rotor. There are two possible frictional parts, one may be the shaft-segment seal or the bulkhead-seal of the low-pressure rotor, and the other may be the friction at the top-steam seal of the low-pressure rotor blade. When the contact is wiped off due to friction, the vibration returns to normal.
1.3 On Jan. 7, 1998, the No. 1 unit of Shuangliao Power Plant started to vibrate with high vibration. Remote fault diagnosis Vibration of the No. 1 unit of Shuangliao Power Plant exceeded the limit on January 7, 1998. In Figure 6. It can be seen from Fig. 6 that at 300r/min, the 3-W vertical, 3-axis X and 3-axis Y-direction vibrations increase with time; at the time of deceleration, the over-critical vibration of each measurement point increases significantly. The maximum vibration at 3 watts was 230 μm at the time of speed reduction, and the maximum vibrations of the 3-axis X and 3-axis Y were 240 μm and 420 μm. From the figure, it can be seen that friction occurs in the low-pressure rotor. There are two possible locations for the friction. One is only in the shaft seal, the partition seal, and the other at the top of the blade and the spacer. This in turn causes radial and static friction between the shaft seal and the diaphragm seal.
After the shutdown and demolition inspection, it was found that the top shroud of the last stage of the low-pressure rotor had a friction at the top shroud, and the shroud of the generator side was removed afterwards.
1.4 January 19, 1998 Shuangliao power plant No. 1 remote vibration fault diagnosis of the machine on January 19, 1998 Shuangliao power plant No. 1 machine vibration overrun. The power plant contacted us in a timely manner and transmitted the vibration data to the Thermal Engineering Institute through remote communication. The analysis results are shown in FIG.
According to the vibration data from the remote communication, we analyzed the vibration variation and frequency spectrum characteristics of the No. 1 unit of the Shuangliao Power Plant during the first month of January. The vibration increase was from 240 MW to 5:44 at 5:00 on the 19th. The 260 MW load condition is mainly reflected in No. 3 and No. 4 bearings. Among them, bearing No. 3 bearing vibration increased from about 30μm to a maximum of about 60μm. Bearing No. 3 bearing X and Y axis vibrations increased from 70μ and 65tμ to about 150μm and 90μm respectively. No. 4 bearing Y-axis vibration increased from about 30μm. As large as 150μm or so. The vibration value is the maximum when the load condition is around 250 Mw, and then the vibration gradually decreases as the load increases. After 6:00, the unit vibration returned to normal. In addition, when the vibration increased, No. 3 Watt vibration, the vibration frequency spectrum of No. 3 and No. 4 bearing shaft vibration was dominated by the fundamental frequency component (1X).
From the analysis, it can be seen that the vibration variation of each bearing first gradually increases, then gradually decreases and returns to normal, and the vibration spectrum component is mainly 1X component. Therefore, the vibration is judged as frictional vibration, which may be the low pressure during the loading process. Rotor hits and touches the rotor. There are two possible positions where dynamic and static friction occur. One is at the steam seal, and the other may be rubbing at the top of the blade and the bulkhead, the shaft seal or the bulkhead.
Shuangliao Power Plant once in January 1998, the shutdown inspection found that the last stage of the low-voltage with surrounding friction, and some of the shroud rivets were swept away, which further shows that the above diagnosis is correct.
2. Remote vibration analysis and diagnosis of Unit X in Yibin Power Generation Plant The Yibin Power Generation Plant No. X was an Eastern 200MW unit with vibration overrun at startup. The relevant data is collected through remote communications and the analysis results are shown in Figure 8-10.
(1) It can be seen from Fig. 8 that the vibration changes with time when the unit load is constant. On July 4, 1997, from 8:00 to 8:45, the five- and six-watt vibrations increased continuously, and the increase in vibration was caused by friction.
(2) Figures 9 and 10 show the 5-watt and 6-watt vibration Bode plots for several times during July 2, 1997 and July 4, 1997. From Fig. 9 and Fig. 10, it can be seen that the vibration at the deceleration over the critical speed is greater than the vibration at the speed up over the critical speed. This is due to the fact that the shaft is bent due to friction, which changes the balance of the shaft system.
(3) From the above analysis, it is shown that the vibration change is caused by friction. From the analysis of the vibration change trend, the friction causes friction between the shaft seal and the shaft.
The power plant demolition inspection on July 6 found signs of shaft seal friction. After the shaft seal gap is enlarged and the control operation is performed, the shaft seal is wiped off and a small amount of imbalance is added to the low-rotation pair. The vibration problem is solved.
3. Remote vibration analysis and fault diagnosis of No. 5 unit of Qingzhen Power Plant The Qingzhen Power Plant No. 5 machine 50MW unit, when started on April 21, 1997, the vibration exceeded the limit. The relevant vibration data stored by the ZJZ-1 system was sent to the Vibration Research Center of the Thermal Engineering Institute through remote communication. The results of the vibration analysis of the remote communication data are not shown in Figure 11 and Table 1-2. The analysis results are as follows:
(1) When started on April 21, 1997, the vibration exceeded the limit when the rotational speed reached around 3000r/min. It can be seen from the vibration values ​​of the 1-watt level (1 watt-) pass frequency, 2 watts vertical (2 watts +), and 2 watts horizontal (2 watts) pass frequency when the No. 5 engine of Qingzhen Power Plant is increasing in speed in Fig.11. When the rotation speed is 3000 r/min), the 1 watt level (1 watt-) vibration increases by about 18 μm, and the 2 watts vertical (2 watts +) and 2 watt levels (2 watts -) vibrations increase by 50 μm and 35 μm, respectively.
It can be seen from the changes in vibration of Fig. 11 that the speed of overshooting is significantly increased. From the above, it can be seen that the reason for the vibration overrun at the start of April 21 is due to radial friction. .
(2) Table 1 and Table 2 show the vibration values ​​at the start of April 21, 1997. It can also be seen from Table 1 and Table 2 that the vibration increases significantly at a given speed, which is caused by radial friction.
After the unit was shut down, it was started again by the low-speed rolling stock. During the speeding up process, the vibration does not increase with time, but the 2 watt vibration in the vertical direction is still too large.
4. Qingzhen Power Plant No. 5 unit long-distance vibration balance treatment Since No. 5 unit is full load, 2 watt vibration is still too large, the power plant wants to make dynamic balance to reduce its vibration. According to the calculation of the vibration data of the long-distance communication, it is given from Xi'an that the weight of the final impeller is 336 grams and the direction is 180. After the power plant was accentuated, the 2 watt vibration was reduced, which solved the problem of vibration of the No. 5 machine and reduced the downtime for at least 2-3 days. The direct economic and social benefits were obvious.
5. The remote vibration fault diagnosis of No. 2 unit of Pucheng Power Plant Pudong Power Plant No. 2 was Romania's 330MW unit, which was started at the end of December 1997. At a 1500 r/min moderate speed warm-up, the generator's rear shim vibration slowly increased over time from 15 μm to 70 μm. From the analysis of the NDZJZ-2 type system produced by the Thermal Power Institute, it can be seen that the vibration component is mainly the 3 times frequency component, which is excluded as the possibility of dynamic or static friction or Mova vibration failure, and the analysis is structural resonance. After the scene changed the rotational speed from 1500r/min to 1800r/min, the 6-watt vibration immediately decreased, and the 3X component gradually disappeared. This reduces one downtime.
III. Analysis of Economic Benefits and Social Benefits From the above application examples, the turbine vibration monitoring and fault diagnosis system manufactured by the Thermal Power Institute of the Ministry of Electric Power was installed in each unit of the power plant, and a remote vibration analysis and fault diagnosis center was established. With obvious economic and social benefits.
1. The existence and development of faults in a timely manner can be promptly announced so that maintenance personnel can formulate maintenance schedules in a timely manner, shorten maintenance time, reduce maintenance costs, and avoid blindly making maintenance projects. For example: When the No. 1 unit of Shuangliao Power Plant suffered from a vibration failure, all the information was saved, so that it was clearly known that the faulty shaft segment was a low-pressure rotor. Only check the low pressure rotor at the time of shutdown, and accurately find the friction of the last blade shroud, reduce the blind stop 2 times, and reduce the inspection cycle 2-3 days. Its direct economic benefits nearly 500 million.
2. Timely capture of fault information, reducing the repeated start-stop test for finding the cause of vibration of the unit. Improve troubleshooting accuracy. For example, the friction of the No. 1 unit of Shuangliao Power Plant started on December 26, 1996. The system captures the entire development process of the fault and determines the position of the friction in the generator through the remote fault diagnosis center. It quickly eliminates vibration, reduces start-up and shut-down at least 1-2 times, generates power 2-3 days in advance, and has direct economic benefits of more than 300 million yuan. .
3. Reduce the number of start and stop times of the unit when seeking balance.
For example, the dynamic balance of No. 5 engine in Qingzhen Power Plant obtains vibration data of the unit through long-distance communication, and gives weighted blocks in Xi’an to reduce downtime by 2-3 days. The direct economic benefit is nearly RMB 1 million.
(Editor's Note: Due to limited space, the drawings and tables will be omitted. Please contact the Thermal Institute Huang Xiuzhu if necessary)
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