The new engineering concept aims to train high-quality engineering talents to meet the needs of future science and technology and industrial development through the reform of education and teaching.Under the backgroun...The new engineering concept aims to train high-quality engineering talents to meet the needs of future science and technology and industrial development through the reform of education and teaching.Under the background of"new engineering",by introducing cutting-edge knowledge of the industry and interdisciplinary integration,adopting innovative teaching methods such as project-driven teaching and flipped classroom,strengthening experimental teaching and school-enterprise cooperation,and establishing comprehensive evaluation and feedback mechanism,Food Machinery and Equipment course is reformed to improve the teaching quality and train high-quality engineering talents to meet the needs of modern food processing industry.展开更多
Spinning equipment: continuous growth of automation demand In order to meet the urgent needs of downstream spinning industry to save labor and reduce the labor intensity of workers, spinning equipment enterprises cont...Spinning equipment: continuous growth of automation demand In order to meet the urgent needs of downstream spinning industry to save labor and reduce the labor intensity of workers, spinning equipment enterprises continue to carry out technological innovation and upgrading, and overall maintain a stable development. With the market situation warming up, spinning machinery orders showed a good growth momentum in the first quarter of 2019. With the stop of expansion of domestic spinning production scale, developing international market in 2019 will become an important development direction for spinning equipment enterprises.展开更多
Thermal spraying has reached a status of its own technical discipline in engineering and become an important industrial technology in China. This paper deals with the latest developments of thermal spraying equipment ...Thermal spraying has reached a status of its own technical discipline in engineering and become an important industrial technology in China. This paper deals with the latest developments of thermal spraying equipment and processes as well as their application in China in recent years. In addition, five kinds of powders were used for plasma spraying to renovate worn parts of heavyduty vehicles and a simple and convenient optimizing method for process parameters of plasma spraying was studied. As a result, the service lives of renovated parts by plasma spraying were increased 2.77 to 8.33 times and an existence of a practical power input Wo was confirmed.展开更多
Combined with equipment activities such as combat readiness,training, exercises and management, it is proposed that the design of equipment in-service assessment subjects should follow the principles of combination, s...Combined with equipment activities such as combat readiness,training, exercises and management, it is proposed that the design of equipment in-service assessment subjects should follow the principles of combination, stage and operability. Focusing on the design of equipment in-serviceassessment subjects, a design method for in-service assessment subjects basedon the combination of trial and training mode is proposed. Based on theactual use of high-equipment use management and training and the established indicator system, the army’s bottom-level equipment activity subjectsand bottom-level assessments are combined. The indicators are mapped andanalyzed. Through multiple rounds of iterations, the mapping relationshipbetween in-service assessment indicators and military equipment activitysubjects is established. Finally, the equipment activity subjects whose data iscollected (reflecting the underlying assessment indicators) are generated inservice assessment subjects. The orthogonal test method is used to optimizethe samples in the assessment subjects to form an in-service assessmentimplementation plan. Taking a certain type of armored infantry fightingvehicle as an example, the sample optimization design of the initially generatedin-service assessment subjects is analyzed. It provides methods and ideas tocarry out in-service assessment work.展开更多
Zibo Sangde Machinery Equipment Co., Ltd. is the first Manufacturer of Refractory Electric Screw Press in China, in the year of 2008, our company produced the first set 315T Refractory Electric Program-controlled Scre...Zibo Sangde Machinery Equipment Co., Ltd. is the first Manufacturer of Refractory Electric Screw Press in China, in the year of 2008, our company produced the first set 315T Refractory Electric Program-controlled Screw Press in China, which is no friction discs, simple structure, with PLC controlling the brick forming process, no need special operator. Once upon the Press was on the market, it achieved a strong interests and reputations from many Refractory Factories because of its Highefficient, Energy-saving(can save by 40-50% electricity comparing to the Friction Press), manpower reduction and improving the quality of bricks.展开更多
The risk assessment of contract conclusion is the primary and key part of equipment purchase contract risk management. In this paper, based on the fuzzy characteristics of contract risks, and overcoming the traditiona...The risk assessment of contract conclusion is the primary and key part of equipment purchase contract risk management. In this paper, based on the fuzzy characteristics of contract risks, and overcoming the traditional disadvantages of analytic hierarchy process (AHP), the fuzzy analytic hierarchy process (FAHP) of contract conclusion is proposed for meeting the actual need of equipment procurement contract risk assessment, and implementing the risk factors qualitative and quantitative assessments of different working nodes in contract conclusion. Thus, a scientific and reliable important basis is provided for the risk management of equipment procurement contract.展开更多
Floors subjected to mechanical equipment loads frequently present problems associated with excessive vibration which can cause human discomfort or even reduce the structure service life.In this context,this work aims ...Floors subjected to mechanical equipment loads frequently present problems associated with excessive vibration which can cause human discomfort or even reduce the structure service life.In this context,this work aims to develop an analysis methodology in order to assess the fatigue performance of steel-concrete composite floors,when subjected to vibrations induced by mechanical equipment.The studied structural model corresponds to a steel-concrete composite floor spanning 10 m by 10 m,with a total area of 100 m^(2).The numerical model developed for the dynamic analysis adopted the usual mesh refinement techniques present in finite element method(FEM)simulations implemented in the ANSYS program.The investigated floor dynamic response was calculated through the consideration of the dynamic loadings imposed by the mechanical equipment,simulated based on the use of harmonic forces applied on the concrete slabs.Furthermore,the dynamic structural response was performed considering several scenarios for the positioning of the equipment,in order to verify the occurrence of excessive vibration.The fatigue assessment is based on a linear cumulative damage rule through the use of the Rainflow-counting algorithm and S-N curves from traditional design codes.The results of this investigation indicated that the equipment position affects directly the floor dynamic structural response and also significantly influences the structure service life.展开更多
Because of poor lubrication, the abrasion of the engineering equipment's key connection position (the hinge joint and so on) has become the major factor that affects the mechanical benefit. The excavator WY60 is ta...Because of poor lubrication, the abrasion of the engineering equipment's key connection position (the hinge joint and so on) has become the major factor that affects the mechanical benefit. The excavator WY60 is taken as an example in this paper. The automatic grease-pouring, the working state test, and the alarm for fault of every lubricating point on the machine is accomplished by the control sub-system, the lubricating system and other correlated components. The principle and functions of the system are described. The work condition is analyzed. Finally, we present the plan of the software and the hardware of the system, and set up the fuzzy assessment model of reliability of the system.展开更多
Ningbo TenderingCenter of Machinery andElectric Equipment wasestablished with the ap-proval by the CompetantState Department andNingbo Municipal Gov-ernment.It is a legal en-tity subordinated to Ning-bo Municipal Econ...Ningbo TenderingCenter of Machinery andElectric Equipment wasestablished with the ap-proval by the CompetantState Department andNingbo Municipal Gov-ernment.It is a legal en-tity subordinated to Ning-bo Municipal EconomicCommittee,specializingin tendering service un-der the supervision,in-spection and guidance ofthe China National Ten-dering Center of Machin-ery and Electric Equip-ment.展开更多
To scientifically evaluate the equipment system of systems(SoS)contribution rate,a contribution rate calculation method based on a structural equation model(SEM)is proposed in this paper.The connotation and evaluation...To scientifically evaluate the equipment system of systems(SoS)contribution rate,a contribution rate calculation method based on a structural equation model(SEM)is proposed in this paper.The connotation and evaluation process of the equipment SoS contribution rate were redefined and standardized.To solve the existing problems in the application of the original contribution rate formula,a modified contribution rate calculation formula is proposed.Finally,the contribution rate evaluation index was divided into latent and explicit variables.The measurement and structural equations in the SEM were used to calculate and analyze the latent variables.The simulation results show that the number of defense lines of air defense weapon equipment has a greater impact on the linear configuration than the group configuration.When the number of K-type air defense weapons is sufficient,the two-layer linear configuration should be adopted with 20 air defense weapon systems.When the number of K-type air defense weapons is insufficient,the single-layer group configuration should be adopted with 12 air defense weapon systems.展开更多
In this paper, we conduct research on the essential network equipment risk assessment method based on vulnerability scanning technology. A growing number of hackers wanton invasion of the computer, through the network...In this paper, we conduct research on the essential network equipment risk assessment method based on vulnerability scanning technology. A growing number of hackers wanton invasion of the computer, through the network to steal important information, or destroy the network, the paralyzed which caused huge losses to the state and society. Find a known vulnerability rather than to find the unknown vulnerabilities much easier, which means that most of the attacker' s use is common vulnerabilities. Therefore, we adopt the advantages of the technique to finalize the methodology for the essential network equipment risk assessment which will be meaningful.展开更多
Based on analyzing the mining equipment life evaluation theoretical system, the equipment life evaluation target system of the mining machinery is put forward taking the economic life, security life, reliability life ...Based on analyzing the mining equipment life evaluation theoretical system, the equipment life evaluation target system of the mining machinery is put forward taking the economic life, security life, reliability life and technical life as the targets. Then, the structure and model of the mining equipment life evaluation system are established and prepared for the realization of the system theoretically. Taking hydraulic support as the research object, the life evaluation system of hydraulic support is established and practice shows that the life evaluation system is feasible.展开更多
In view of complex geological characteristics and alternating loading conditions associated with cyclic large amount of gas injection and withdrawal in underground gas storage(UGS) of China, a series of key gas storag...In view of complex geological characteristics and alternating loading conditions associated with cyclic large amount of gas injection and withdrawal in underground gas storage(UGS) of China, a series of key gas storage construction technologies were established, mainly including UGS site selection and evaluation, key index design, well drilling and completion, surface engineering and operational risk warning and assessment, etc. The effect of field application was discussed and summarized. Firstly, trap dynamic sealing capacity evaluation technology for conversion of UGS from the fault depleted or partially depleted gas reservoirs. A key index design method mainly based on the effective gas storage capacity design for water flooded heterogeneous gas reservoirs was proposed. To effectively guide the engineering construction of UGS, the safe well drilling, high quality cementing and high pressure and large flow surface injection and production engineering optimization suitable for long-term alternate loading condition and ultra-deep and ultra-low temperature formation were developed. The core surface equipment like high pressure gas injection compressor can be manufactured by our own. Last, the full-system operational risk warning and assessment technology for UGS was set up. The above 5 key technologies have been utilized in site selection, development scheme design, engineering construction and annual operations of 6 UGS groups, e.g. the Hutubi UGS in Xinjiang. To date, designed main indexes are highly consistent with actural performance, the 6 UGS groups have the load capacity of over 7.5 billion cubic meters of working gas volume and all the storage facilities have been running efficiently and safely.展开更多
A new type taphole drill was designed. The vibration properties of them drill-punch mechanism for the new type taphole drill were researched, the laws of its inherent characteristics were found. The measures to add pu...A new type taphole drill was designed. The vibration properties of them drill-punch mechanism for the new type taphole drill were researched, the laws of its inherent characteristics were found. The measures to add punch amplitude and to reduce traverse vibration were put forward. The result showed that decreasing the frequency of vibration motors or increasing the stiffness of springs, and increasing excitation force can improve the vibration properties of the properties of the drill-punch mechanism.展开更多
With its headquarters in Nanjing and founded in 1978, the Jiangsu Machinery & Equipment Import & Export (Group) Corporation is one of the major members of the China machinery & Equipment Import & Expor...With its headquarters in Nanjing and founded in 1978, the Jiangsu Machinery & Equipment Import & Export (Group) Corporation is one of the major members of the China machinery & Equipment Import & Export Group. It has over twenty exclusive investment or holding companies at home and abroad,展开更多
There are very few studies of the Carbon Footprint of Products (CFPs) in the service sector (e.g. transport and waste treatment) in comparison with those of industrial products and farm products. In this study, the CF...There are very few studies of the Carbon Footprint of Products (CFPs) in the service sector (e.g. transport and waste treatment) in comparison with those of industrial products and farm products. In this study, the CFPs of the recycling services of used beverage cans (aluminum and steel) and waste papers (cardboard, magazine and newspaper) in waste treatment were estimated as a first trial model of the service sector. Regarding the CFPs of whole life cycle of the recycling services, the amounts of CO2-equivalent (CO2e) greenhouse gas (GHG) emissions from the collection and transportation process were the largest in all recycling cases. The reason that the collection and transportation process emits the largest amounts of GHG emissions is that the collection vehicles (trucks) consume the large amounts of diesel fuel. Regarding the CFPs of the capital equipment, the amounts of GHG emissions from the capital equipment were the second largest in all recycling cases. It was found that the percentages of amounts of GHG emissions from the capital equipment in the recycling services were larger than those of industrial products and farm products.展开更多
Power transformer is one of the most important equipment in the power system.Its operating condition affects the reliability of power supply directly.Therefore,in order to guarantee transformer operation safely and re...Power transformer is one of the most important equipment in the power system.Its operating condition affects the reliability of power supply directly.Therefore,in order to guarantee transformer operation safely and reliably,it is necessary to assess condition of power transformer accurately.Return voltage method based on voltage response measurements is still a new non-intrusive diagnosis method for internal insulation aging of transformer.In this paper the technique and application of return voltage measurement and some results of voltage response measurements of several transformers was introduced.Voltage response measurements were performed on various transformers with different voltage grades,various operating periods,different moisture contents and aging degrees on site.Derived moisture contents from return voltage measurement were compared with the corresponding moisture contents obtained from the analysis of oil samples.Based on on-site experiments and theoretical analysis,the criteria for insulation state of transformer are proposed.Moisture condition of transformer insulation can be determined by using return dominant time constant,and a good correlation between aging degree and the return voltage initial slopes of the aged transformers.Field test performed on several transformers,its interpretation of results are also presented,which proves that return voltage measurements can be used as a reliable tool for evaluating moisture content in transformer insulation.展开更多
For purchasing spare parts for machinery products, the general principle, procedure and method are put forward in the paper. Fuzzy theory and method are applied to set up a decisive model for purchasing spare parts. B...For purchasing spare parts for machinery products, the general principle, procedure and method are put forward in the paper. Fuzzy theory and method are applied to set up a decisive model for purchasing spare parts. By working out the kinds and quantities of spare parts, the purchase of parts is provided with scientific decision.展开更多
文摘The new engineering concept aims to train high-quality engineering talents to meet the needs of future science and technology and industrial development through the reform of education and teaching.Under the background of"new engineering",by introducing cutting-edge knowledge of the industry and interdisciplinary integration,adopting innovative teaching methods such as project-driven teaching and flipped classroom,strengthening experimental teaching and school-enterprise cooperation,and establishing comprehensive evaluation and feedback mechanism,Food Machinery and Equipment course is reformed to improve the teaching quality and train high-quality engineering talents to meet the needs of modern food processing industry.
文摘Spinning equipment: continuous growth of automation demand In order to meet the urgent needs of downstream spinning industry to save labor and reduce the labor intensity of workers, spinning equipment enterprises continue to carry out technological innovation and upgrading, and overall maintain a stable development. With the market situation warming up, spinning machinery orders showed a good growth momentum in the first quarter of 2019. With the stop of expansion of domestic spinning production scale, developing international market in 2019 will become an important development direction for spinning equipment enterprises.
文摘Thermal spraying has reached a status of its own technical discipline in engineering and become an important industrial technology in China. This paper deals with the latest developments of thermal spraying equipment and processes as well as their application in China in recent years. In addition, five kinds of powders were used for plasma spraying to renovate worn parts of heavyduty vehicles and a simple and convenient optimizing method for process parameters of plasma spraying was studied. As a result, the service lives of renovated parts by plasma spraying were increased 2.77 to 8.33 times and an existence of a practical power input Wo was confirmed.
文摘Combined with equipment activities such as combat readiness,training, exercises and management, it is proposed that the design of equipment in-service assessment subjects should follow the principles of combination, stage and operability. Focusing on the design of equipment in-serviceassessment subjects, a design method for in-service assessment subjects basedon the combination of trial and training mode is proposed. Based on theactual use of high-equipment use management and training and the established indicator system, the army’s bottom-level equipment activity subjectsand bottom-level assessments are combined. The indicators are mapped andanalyzed. Through multiple rounds of iterations, the mapping relationshipbetween in-service assessment indicators and military equipment activitysubjects is established. Finally, the equipment activity subjects whose data iscollected (reflecting the underlying assessment indicators) are generated inservice assessment subjects. The orthogonal test method is used to optimizethe samples in the assessment subjects to form an in-service assessmentimplementation plan. Taking a certain type of armored infantry fightingvehicle as an example, the sample optimization design of the initially generatedin-service assessment subjects is analyzed. It provides methods and ideas tocarry out in-service assessment work.
文摘Zibo Sangde Machinery Equipment Co., Ltd. is the first Manufacturer of Refractory Electric Screw Press in China, in the year of 2008, our company produced the first set 315T Refractory Electric Program-controlled Screw Press in China, which is no friction discs, simple structure, with PLC controlling the brick forming process, no need special operator. Once upon the Press was on the market, it achieved a strong interests and reputations from many Refractory Factories because of its Highefficient, Energy-saving(can save by 40-50% electricity comparing to the Friction Press), manpower reduction and improving the quality of bricks.
文摘The risk assessment of contract conclusion is the primary and key part of equipment purchase contract risk management. In this paper, based on the fuzzy characteristics of contract risks, and overcoming the traditional disadvantages of analytic hierarchy process (AHP), the fuzzy analytic hierarchy process (FAHP) of contract conclusion is proposed for meeting the actual need of equipment procurement contract risk assessment, and implementing the risk factors qualitative and quantitative assessments of different working nodes in contract conclusion. Thus, a scientific and reliable important basis is provided for the risk management of equipment procurement contract.
基金the support for this work provided by the Brazilian Science Foundations:CAPES,CNPq and FAPERJ.
文摘Floors subjected to mechanical equipment loads frequently present problems associated with excessive vibration which can cause human discomfort or even reduce the structure service life.In this context,this work aims to develop an analysis methodology in order to assess the fatigue performance of steel-concrete composite floors,when subjected to vibrations induced by mechanical equipment.The studied structural model corresponds to a steel-concrete composite floor spanning 10 m by 10 m,with a total area of 100 m^(2).The numerical model developed for the dynamic analysis adopted the usual mesh refinement techniques present in finite element method(FEM)simulations implemented in the ANSYS program.The investigated floor dynamic response was calculated through the consideration of the dynamic loadings imposed by the mechanical equipment,simulated based on the use of harmonic forces applied on the concrete slabs.Furthermore,the dynamic structural response was performed considering several scenarios for the positioning of the equipment,in order to verify the occurrence of excessive vibration.The fatigue assessment is based on a linear cumulative damage rule through the use of the Rainflow-counting algorithm and S-N curves from traditional design codes.The results of this investigation indicated that the equipment position affects directly the floor dynamic structural response and also significantly influences the structure service life.
基金This paper is supported by Scientific Research Foundation of PLAGeneral Equipment Departmentunder Contract No.20060210
文摘Because of poor lubrication, the abrasion of the engineering equipment's key connection position (the hinge joint and so on) has become the major factor that affects the mechanical benefit. The excavator WY60 is taken as an example in this paper. The automatic grease-pouring, the working state test, and the alarm for fault of every lubricating point on the machine is accomplished by the control sub-system, the lubricating system and other correlated components. The principle and functions of the system are described. The work condition is analyzed. Finally, we present the plan of the software and the hardware of the system, and set up the fuzzy assessment model of reliability of the system.
文摘Ningbo TenderingCenter of Machinery andElectric Equipment wasestablished with the ap-proval by the CompetantState Department andNingbo Municipal Gov-ernment.It is a legal en-tity subordinated to Ning-bo Municipal EconomicCommittee,specializingin tendering service un-der the supervision,in-spection and guidance ofthe China National Ten-dering Center of Machin-ery and Electric Equip-ment.
基金The National Social Science Foundation Military Science Project(No.16GJ003-068).
文摘To scientifically evaluate the equipment system of systems(SoS)contribution rate,a contribution rate calculation method based on a structural equation model(SEM)is proposed in this paper.The connotation and evaluation process of the equipment SoS contribution rate were redefined and standardized.To solve the existing problems in the application of the original contribution rate formula,a modified contribution rate calculation formula is proposed.Finally,the contribution rate evaluation index was divided into latent and explicit variables.The measurement and structural equations in the SEM were used to calculate and analyze the latent variables.The simulation results show that the number of defense lines of air defense weapon equipment has a greater impact on the linear configuration than the group configuration.When the number of K-type air defense weapons is sufficient,the two-layer linear configuration should be adopted with 20 air defense weapon systems.When the number of K-type air defense weapons is insufficient,the single-layer group configuration should be adopted with 12 air defense weapon systems.
文摘In this paper, we conduct research on the essential network equipment risk assessment method based on vulnerability scanning technology. A growing number of hackers wanton invasion of the computer, through the network to steal important information, or destroy the network, the paralyzed which caused huge losses to the state and society. Find a known vulnerability rather than to find the unknown vulnerabilities much easier, which means that most of the attacker' s use is common vulnerabilities. Therefore, we adopt the advantages of the technique to finalize the methodology for the essential network equipment risk assessment which will be meaningful.
基金supported by the Natural Science Foundation of Shanxi Province,China under Grant Number:2008012006-2
文摘Based on analyzing the mining equipment life evaluation theoretical system, the equipment life evaluation target system of the mining machinery is put forward taking the economic life, security life, reliability life and technical life as the targets. Then, the structure and model of the mining equipment life evaluation system are established and prepared for the realization of the system theoretically. Taking hydraulic support as the research object, the life evaluation system of hydraulic support is established and practice shows that the life evaluation system is feasible.
基金Supported by the CNPC Science and Technology Major Project(2015E-4002)
文摘In view of complex geological characteristics and alternating loading conditions associated with cyclic large amount of gas injection and withdrawal in underground gas storage(UGS) of China, a series of key gas storage construction technologies were established, mainly including UGS site selection and evaluation, key index design, well drilling and completion, surface engineering and operational risk warning and assessment, etc. The effect of field application was discussed and summarized. Firstly, trap dynamic sealing capacity evaluation technology for conversion of UGS from the fault depleted or partially depleted gas reservoirs. A key index design method mainly based on the effective gas storage capacity design for water flooded heterogeneous gas reservoirs was proposed. To effectively guide the engineering construction of UGS, the safe well drilling, high quality cementing and high pressure and large flow surface injection and production engineering optimization suitable for long-term alternate loading condition and ultra-deep and ultra-low temperature formation were developed. The core surface equipment like high pressure gas injection compressor can be manufactured by our own. Last, the full-system operational risk warning and assessment technology for UGS was set up. The above 5 key technologies have been utilized in site selection, development scheme design, engineering construction and annual operations of 6 UGS groups, e.g. the Hutubi UGS in Xinjiang. To date, designed main indexes are highly consistent with actural performance, the 6 UGS groups have the load capacity of over 7.5 billion cubic meters of working gas volume and all the storage facilities have been running efficiently and safely.
文摘A new type taphole drill was designed. The vibration properties of them drill-punch mechanism for the new type taphole drill were researched, the laws of its inherent characteristics were found. The measures to add punch amplitude and to reduce traverse vibration were put forward. The result showed that decreasing the frequency of vibration motors or increasing the stiffness of springs, and increasing excitation force can improve the vibration properties of the properties of the drill-punch mechanism.
文摘With its headquarters in Nanjing and founded in 1978, the Jiangsu Machinery & Equipment Import & Export (Group) Corporation is one of the major members of the China machinery & Equipment Import & Export Group. It has over twenty exclusive investment or holding companies at home and abroad,
文摘There are very few studies of the Carbon Footprint of Products (CFPs) in the service sector (e.g. transport and waste treatment) in comparison with those of industrial products and farm products. In this study, the CFPs of the recycling services of used beverage cans (aluminum and steel) and waste papers (cardboard, magazine and newspaper) in waste treatment were estimated as a first trial model of the service sector. Regarding the CFPs of whole life cycle of the recycling services, the amounts of CO2-equivalent (CO2e) greenhouse gas (GHG) emissions from the collection and transportation process were the largest in all recycling cases. The reason that the collection and transportation process emits the largest amounts of GHG emissions is that the collection vehicles (trucks) consume the large amounts of diesel fuel. Regarding the CFPs of the capital equipment, the amounts of GHG emissions from the capital equipment were the second largest in all recycling cases. It was found that the percentages of amounts of GHG emissions from the capital equipment in the recycling services were larger than those of industrial products and farm products.
基金Project Supported by Science and Technology Fund of Fujian E-lectric Power Limited Company(NC2006044)Scientific Research Fund of Fujian Education Depart ment(JB06045)
文摘Power transformer is one of the most important equipment in the power system.Its operating condition affects the reliability of power supply directly.Therefore,in order to guarantee transformer operation safely and reliably,it is necessary to assess condition of power transformer accurately.Return voltage method based on voltage response measurements is still a new non-intrusive diagnosis method for internal insulation aging of transformer.In this paper the technique and application of return voltage measurement and some results of voltage response measurements of several transformers was introduced.Voltage response measurements were performed on various transformers with different voltage grades,various operating periods,different moisture contents and aging degrees on site.Derived moisture contents from return voltage measurement were compared with the corresponding moisture contents obtained from the analysis of oil samples.Based on on-site experiments and theoretical analysis,the criteria for insulation state of transformer are proposed.Moisture condition of transformer insulation can be determined by using return dominant time constant,and a good correlation between aging degree and the return voltage initial slopes of the aged transformers.Field test performed on several transformers,its interpretation of results are also presented,which proves that return voltage measurements can be used as a reliable tool for evaluating moisture content in transformer insulation.
文摘For purchasing spare parts for machinery products, the general principle, procedure and method are put forward in the paper. Fuzzy theory and method are applied to set up a decisive model for purchasing spare parts. By working out the kinds and quantities of spare parts, the purchase of parts is provided with scientific decision.