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Thermal power equipment maintenance | power plant condition-based maintenance of the status quo and ideas

Author: XuGang From: www.yourpaper.net Posted: 2007-11-23 09:55:10 Read:
Abstract: This paper briefly introduces the current popular unit state monitoring and maintenance of the significance and Yunfeng Power Plant Unit Condition Monitoring and condition maintenance condition, put forward the unit state monitoring and condition-based maintenance plan, for reference.
Keywords: unit condition monitoring   state maintenance; condition monitoring system of
effect of Yunfeng Power Plant in the power system is mainly responsible for the peak, FM, emergency task, to achieve the above purpose, requirement unit must have good reliability and scalability.According to the northeast of repair work of hydropower plant state requirements, our factory has carried out preliminary work of equipment condition maintenance, and plant a, to become a pilot unit condition maintenance in Northeast China hydropower.At present, our factory has been the maintenance and operation history data of four units, systematically collected and compiled, in water, electric power research institute.In recent years, the overhaul of unit Yunfeng Power Plant by the traditional plan gradually transition to the state, the maintenance mode from the original 'maturity required, maintenance required good', to 'the required repair, maintenance required good' transition.In the aspect of on-line monitoring equipment maintenance, state the preliminary results are.
1 turbine condition monitoring system of
overview
in recent years, condition-based maintenance of hydropower equipment (i.e., predictive repair) has attracted more and more attention from.Necessary conditions for condition-based maintenance to condition monitoring and fault diagnosis.Random or periodic testing of the equipment in the running process of the whole or part of the physical phenomena, is the state monitoring.And the equipment fault diagnosis technology is a kind of understanding and knowledge of equipment in use condition, to determine the overall or partial is normal, early detection of faults and their causes, and integrated technology development trend forecast failure of hardware or software.Condition monitoring and diagnosis technology and equipment as a basic means, to provide practical basis for the state monitoring, in order to arrange the repair, ensure safe and economic operation of equipment.
The key of equipment condition monitoring and diagnosis is on-line monitoring technology, including information collection, processing and analysis, data processing and decision making.On-line monitoring can be effective at any time to master the technology condition of equipment and the deterioration law, to avoid the occurrence of sudden accident and control of gradual fault.
Practice has proved, the implementation of on-line monitoring device can reduce the unnecessary shutdown, reduce repair cost, increase the available time, thereby improving the operation efficiency of equipment repair.
1.1 existence of the drawbacks of
units planning maintenance
Condition maintenance work before the implementation, maintenance of four units of our factory is carried out according to plan maintenance principle, according to the Ministry of water conservancy and electric power issued a "power plant maintenance procedures" provisions of the maintenance cycle, maintenance period, maintenance and other indicators, 'maturity required, maintenance required good', in fact, the Ministry for unit maintenance cycle, maintenance time and maintenance project basis set is basically similar equipment maintenance experience, does not have the universal significance.After years of technical practice, we recognize, such provisions with habitual larger, is a method of master apprentice learning style, more conservative, blind, but also grasp, in addition to waste some human, material, material resources, time, generally not what big mistake.But from the equipment maintenance is to eliminate the defects, ensure the healthy operation of equipment this perspective, planned maintenance is not reasonable.The so-called 'maturity required' equipment is running to a prescribed period of time, whether in the state of technology, what have no defects are downtime.Because of the design of our factory units of manufacturing, operating conditions are not the same, even similar equipment in operation in the same period, also show significant differences.At the same time, 'maturity required' often unnecessarily dismantling, waste not only made the adult, wood, fabric, sometimes equipment overhaul bad, cause 'work.'.
1.2 equipment state maintenance advantages of
Through continuous exploration and practice, we realize that, the core state maintenance is through the diagnosis for the equipment, find out the actual situation of equipment, and use it as the basis for making maintenance plan feasible implementation.Condition based maintenance of popular argument is' the required repair, maintenance required good ', its emphasis is on' the required repair 'of' the ', the' the 'words reflect the nature the maintenance work, it requires decided to repair and not repair, repair or overhaul to have the full facts after repeated demonstration, to this and should not, not as a rule of thumb, not the firm not to repair, the repair is firmly fixed, only in this way can be just perfect, complete maintenance tasks.
We also recognize, condition-based maintenance is more consistent with the 'prevention first' principle than planned maintenance.The biggest drawback is not decided to overhaul maintenance content according to the actual state of technology equipment, and let the program period hoop too dead, state maintenance is not, it is decided to overhaul contents through diagnosis means different out of current technology equipment after, it can according to the requirements of technical state and operating equipment, advance or defer maintenance cycle, increase or reduce maintenance project, realize the purpose of maintenance, and has the largest economic benefits.Obviously, state maintenance control of eliminating equipment defects, consistent with the law of development of the equipment operation, in accordance with the principle of nip in the bud.
1.3 our initial implementation of condition-based maintenance are the benefits after
Prior to the implementation of condition-based maintenance, parameters of running state of the reflection of the four units of the plant was only stay in manual detection stage, through experimental observation, regular reference standard, technical condition analysis equipment maintenance plan.Due to the lack of reliable and effective diagnosis method and diagnosis instrument, making maintenance plan is not fully effective.In 1991, I plant and Huazhong University of electric department cooperation, jointly developed the first generation BZJ1 Swing-Vibrating monitor, the instrument in 1992 September installation in our factory No. four turbine generator unit.Limited by the technical condition of the time, measured points less, at the same time logging data and manually measured data is different, not affected by field workers welcome.I plant in 1996 and the Hainan state science and technology company to develop test and data analysis and processing system for hydroelectric generating set vibration SZJ.The system consists of a Swing-Vibrating monitor (BZJ), multiplex communication controller (DTC), data processing and analysis software package (SFC) is composed of three parts, BZJ will collect data by RS232 serial port by DTC sent to the host computer, and then by SFC analysis and processing.The system was installed in 2, 3, 4 units of our factory.At the end of 2000, our factory cooperation with Shenzhen Lida Company, developed jointly by the state unit, mechanical analysis and fault diagnosis system (SZJ99), as a system of the system, and the computer monitoring system is not connected.The function of the system is the first two generation is enhanced, the monitoring channel is increased from 9 to 17, the signal waveform acquisition in circuit test at the same time, transient process and waveform recording unit.The system in the mechanical vibration monitoring unit and real time analyzer (BZJ3) based vibration data and characteristics provide the, using the theoretical knowledge and practical experience, the formation of analysis software state machine machinery.In order to further analysis of mechanical characteristics set and the reason that caused the abnormal vibration.In order to provide analysis of maintenance and fault unit basis or parameters.Running through the actual data in the system (especially the special status of data) accumulation, help staff to strengthen understanding of the unit mechanical characteristics, improve maintenance level.Through the access network system (this is not currently implemented), full-time staff and the leadership can know the mechanical condition in the distance, in order to meet the needs of hydropower plant 'unattended' (a few people on duty) requirements.
The status maintenance management mode for equipment condition monitoring based, because the actual technical condition of the equipment, I plant the unit overhaul cycle has been changed to 4 years, the unit expanded overhaul cycle has been changed to 10 years.In the past, whether the condition of the equipment, maintenance cycle to, immediately began to design, manufacture, maintenance, installation, maintenance unit of outstanding quality, maintenance too frequently not only the benefits, in most cases is removed to wipe oil, plastering.Increase the maintenance cost unit
, stop time, reduce the unit of adjustable hours.Now because our factory pays attention to in equipment state efforts, to determine the maintenance time and maintenance projects unit through the master unit status, to prolong the maintenance intervals, shorten the maintenance period, reduce cost of repair.According to the equipment state monitoring data and operation control procedures and standards of maintenance time and project, and has received remarkable economic benefit.Such as two units of our factory, in various load conditions, from the view of the monitor data, shall not exceed the specified value, stable equipment operation, but has been running for 14 years not to expand overhaul.Because the unit each routine inspection found that the screw tensioning of generator stator core breaking, while leaf water leakage serious defects of turbine guide vane sleeve, need to be replaced, so according to condition based maintenance of thought, decided to expand the overhaul of the unit after overhauling, improves the reliability of the equipment running.If I plant unit no. four, early stage there is swing, defect vibration, and vibration unit wide area.The implementation of unit state monitoring, reasons for the existence of defects on four units of in-depth research and detailed analysis, to determine the number four machine vibration is mainly caused by unit axis.Through the extended overhaul of the unit, elimination of insulating pad thrust head and the mirror plate, two sealing ring is added in between the runner and thrust head, effectively preventing the contact surface to cause cavitation caused by the deterioration of the axis, thrust head and mirror plate back to factory for processing so, the precision to achieve the specified in the drawing, generating units put into operation, the vibration, runout significantly reduced, to achieve the expected goal.Unit 1 again of our factory, 2001 conducted a general overhaul, repair the unit vibration monitor test found that vertical vibration exciter stator housing reached 0.17-0.20mm, the horizontal vibration reaches 0.18-0.20mm, damage to the unit structure components caused by strong vibration is enormous, according to this situation, we put forward to the Department in charge of expansion and maintenance of application, and to the superior departments to explain the situation, be approved.The decomposition of inspection found, unit axis has worsened, thrust bearing (10) serious wear, serious individual tile surface crack, surface wear and severe deformation of thrust against heavy screw and tray contact, mirror plate working surface has scratches, local position is blue, when the temperature is too high, the bottom face, head, thrust the mirror plate on the back of the cavitation serious.The thrust head, mirror plate, thrust - weight screws and tray are return to factory processing, meet the drawing requirements, and to all the thrust tile was replaced.
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