bluuebunny/crossref_metadata_2025 huggingface dataset:
Surface Crack and Organization of Hot Rolled S31803 Duplex Stainless Steel Bars
Authors: Wu Ming Hua , Liu Zhan Ying , Yang Hui
Published: October 2014

In bar rolling of S31803 duplex stainless steel, the surface crack is easy to appear. Through the observation on the microstructure, ferrite and austenite morphology and phase ratio were analyzed. The surface cracks of S31803 duplex stainless steel bar is mainly because of the dual phase microstructure softening mechanism of different in thermal processing, and the double phase stainless steel heat plasticity decrease. When the ferrite and austenite proportion close, and the heating temperature is too high, to reduce the binding force between the grains of billet surface, easy to cause the crack surface of a bar.
Experimental Study on Evolution of Rock Damage Rule in the Condition of Conventional Three Axis Compression
Authors: He Bing
Published: October 2014

Based on continuum damage mechanics, by defining the initial and critical damage value, because of the plastic volumetric strain of the specimen, we established the calculation methods of the rock specimen’s damage value. Through the conventional triaxial compression test of the shale, we find that damage value D changes as axial strain changes during compression, and summarizes its variation.
Influence of Silica Fume on High-Performance Concrete
Authors: Wang Fan , Zheng Shan Suo , Wang Xiao Fei
Published: October 2014

With the improvement of concrete materials and the emergence of new materials, adding silica fume to high-performance concrete (HPC) has been one of the important ways in concrete technology. In this paper, through experimental study on the mechanical performance of HPC with 5%, 10%, 15% and 20% silica fume replacing cement for different water-binder ratio, along with polycarboxylates high performance water-reducing admixture, silica fume has large effects on 28d compressive strength, split tensile strength and flexural strength of the HPC. Meanwhile, due to the different level of water-binder ratio, the relationship between split tensile strength, flexural strength and compressive strength is also obvious linear.
The Eco-Concrete with the Papermaking Sludge
Authors: Kon Mun Yue , Chou Liang Hsing
Published: October 2014

Porous concrete planted with grass is attractive both environmentally and esthetically for applications in residential driveway, sidewalk and parking lots. Disposal of papermaking sludge is a challenging environmental problem. As a possible solution, grass cultivation in porous concrete filled with mixtures of papermaking sludge and soil was studied. Bermuda grass, Perennial ryegrass, and Tall Fescue were tested. Experimental results showed that the papermaking sludge retarded the germination of grass seeds only slightly, while promoted the growth of grass stems and the development of grass roots significantly. The optimum ratio of the papermaking sludge to soil appears to be in the range of 25 to 50%. Therefore, it is believed that papermaking sludge is suitable for grasses cultivation in the porous concrete.
Groove Deformation on a Heat Resistant Alloy due to Thermal and Thermo-Mechanical Cycling
Authors: Li Feng Xun
Published: October 2014

Thermal barrier coatings (TBCs) provide a good protection to high temperature corrosion of superalloy substrate in gas turbine. However, the lateral growth of the thermally grown oxide (TGO) and the thermal expansion misfit between underlying bond coat (BC) and TGO may induce internal stresses. In this work, the distortion occurring near a groove on a heat-resistant Fecralloy substrate was analyzed due to subjected to thermal and thermo-mechanical cycling. Experimental result shows that the distortion of the groove strongly effected by mechanical load.
Mirror Grinding Process Parameter Selection and Design
Authors: Hua Li , Wang Xiang Jun , Zhou Rui
Published: October 2014

Mirror grinding mainly depends on the precision of the machine tool, cutting and grinding amount and wheel selection and dressing. This paper mainly studies the MG1432 high-precision universal cylindrical grinder, exploring the impact on the workpiece roughness through selection and design of various process parameters in grinding, such as changing work table speed in dressing the grinding wheel and grinding, workpiece linear velocity and excessive feeding. The experimental conditions were: Using resin binder white corundum graphite grinding wheels, workpiece: GCr15 (HRC60); dressing tool: sharp single particle diamond correction pen, and ultimately achieving mirror grinding process results.
Research on the High Temperature Oxidation Stress of Thermal Barrier Coating
Authors: Han Zhi Yong , Jing Zhen Zhu
Published: October 2014

Stress, strain and residual energy of the thermal barrier coatings under high temperature shock were simulated by using ABAQUS software. The results show that cooling rate has certain effects on the residual stress. With the increase of cooling rate, the interface stress between the coating and substrate increased. Rapid cooling resulted in the phase transition and larger residual stress in the coating. With increasing of thermal cycles, the residual stress accumulated gradually. And the residual stress of the fourth thermal cycling increased by half compared with the first time. Moreover, the strain presented an increasing tendency with the increase of thermal cycling times and reached to 23.1097×10-3 μm after the fourth thermal cycling. The residual energy increased to 15.5 J after four thermal cycling and increased 1.2 J compared to the first time.
Effects of Different Heat Treatments on Transformation of Residual Austenite in Bearing Steel
Authors: Liu H.S. , Wang M.H. , Ge X.Y. , Luo H.S.
Published: October 2014

The effect of heat treatment on transformation of residual austenite in bearing steel is studied, by adding the cryogenic treatment into the normal heat treatment process. The results indicate that the residual austenite content is decreased and the hardness is improved obviously, when putting the cryogenic treatment at -70°C or lower directly behind the quenching process. While when the tempering is added between quench and cryogenic treatment, the temperature of cryogenic treatment must be much lower than -70°C to offset the thermal stability of residual austenite, which is given by tempering.
Research on Electrode Design and Computer Simulation of Manufacturing Shrouded Turbine Blisk by EDM
Authors: Li Yan , Zhai Li Jun , Liu Jian Yong
Published: October 2014

A shrouded turbine blisk is taken as the research object. Based on NURBS surface modeling theory and by using SolidWorks software, a 3D model of the blisk was gotten. An electrode was designed according to the characteristic of channel between two blades of the blisk. A set of fixtures for manufacturing the blisk was designed, which can realize measurement on-line. Computer simulation of manufacturing the blisk was conducted. The simulation results show that there is no interference between the blisk and the electrode. So the feasibility of manufacture is verified. The simulation results have provided an effective basis for the subsequent processing of the blisk.
Aerodynamic Analysis of the Rotor/Wing in Conversion Flight
Authors: Wu Jiang Hao , Hu Jie
Published: October 2014

The aerodynamics of the rotor/wing during conversion from rotary to fixed-wing flight was numerical investigated. It is shown that increasing forward speed can provide more thrust when rotation speed and collective angle maintain a constant, but also appear greater torque. Thrust of the rotor/wing can maintain aircraft to hover at some cases when forward speed changes with other variable. As long as major and minor rotor converse with reasonable variable change alternatively, the dual rotor/wing can converse smoothly. Moreover, the total drag of minor first conversion is smaller than that of major first conversion.
Finite Poroelasticity with Surface Effect
Authors: Li Chao Jun , Feng Ji Li
Published: October 2014

This paper presents a consistent theoretical framework for describing the finite poroelasticity with surface effect. The underlying concept of additional pressure that is thought of as an equivalent thermodynamic pressure applying on the pore surface is used to detail the pore pressure. A nonlinear porosity laws is proposed for the finite deformation of porous material. With surface effect consideration, the corresponding constitutive equations are developed. The present model for both the swelling of the matrix and the permeability change of coal induced by adsorption of CO2 and CH4 are presented under different pressure conditions. It is shown that the predictions from the model are good agreement with the experimental data of sorption-induced deformation of coals.
Microstructures and Properties of HAZ of JB800 Bainite Steel
Authors: Sun Jun Sheng , Wang Hong Quan
Published: October 2014

JB800 steel has grain boundary allotriomorphic ferrite and granular bainite (FGBA/BG), and it is a kind of high strength low alloy steels, which has simple produce procedure, lower cost and excelled property. The law of microstructure transformation in CGHAZ, hardness, and impact toughness in HAZ of JB800 steel were studied by means of thermal simulation. The test results show that under the general condition of welding process (t8/5=5~50s), microstructure of CGHAZ is composed of mixture microstructure of Martensite and Bainite and with the increase of cooling rate, the content of Martensite will decrease, but that of Bainite will increase; when t8/5 is 20s, CGHAZ zone have better impact toughness, which is composed of 95% Martensite and 5% Bainite. Therefore t8/5 should be controlled at about 20s to get better impact toughness.
Square Pyramid Partial Double Layer of Schwedler Spherical Reticulated Shell Parametric Design and Mechanical Analysis
Authors: Lu Xiao Yang , Liu Feng Cheng , Zhang Da Liang , Wang Qiao Sha , Shao Bo Lu , Xin Jing , An Ran , Liu Xiu Zhi
Published: October 2014

Using ANSYS software comes with parametric design language APDL, developed a square pyramid partial double layer of Schwedler spherical reticulated shell parametric design macro program; achieved this kind of spherical shell parametric modeling with the given shell span S, vector high F, the thickness (height) of the pyramid, ring copies of the symmetric region Kn and radial nodes laps Nx. Analyzed the static performance of the spherical reticulated shell under different structural parameters, studied the displacement of the structure and the distribution of the stress change with macroscopic geometric parameter change rule. Analysis results of eight kinds of conditions showed that the square pyramid partial double layer of Schwedler spherical reticulated shell has good mechanical performance. The result of the analysis provides a theoretical basis for the relevant engineering design.
Identifying Real Stiffness Properties of Structural Elements of Adapted Finite-Element Models of Buildings and Structures - Part 2: Computational-Experimental Methodology
Authors: Belostotskiy Alexander M. , Novikov Pavel I.
Published: October 2014

The distinctive paper is devoted to new defect identification methodology based on dynamic characteristics of real construction. The methodology is founded on mathematically formalized procedure of FE-model adaptation by measured and calculated eigen pairs of dynamic system. Main steps of the methodology are described. Application of the methodology together with standing wave method might allow to identify deviations of stiffness parameters of a real construction facility.
Numerical Investigation of Stator Blades Bow Effect on the Rotor Blade Erosion of a Wet Steam Turbine
Authors: Yao Hong , Han Wan Long , Pan Shi Ming , Wang Zhong Qi
Published: October 2014

The water droplet erosion protection of the rotor blades has been an important issue for a long time, regardless of the design. The aim of this paper is to present a aerodynamic design method for decrease risk of water droplet erosion in wet steam turbine, as well as to present the comparison between then five diffrent bow stator blades. This paper also presents numerical investigation of three dimensional wet steam flows in a stage. This stage has long transonic blades designed using recent aerodynamic and mechanical design methods. The results show that, the one of the five diffrent bow stator blades decrease rist of water droplet erosion of rotaional blades, and the change of the efficiency is small.
Numerical Study of Single-Mode Interface Shape on Rotary Motion Instability
Authors: Jian Yu
Published: October 2014

Using the method of numerical simulations to study fluid dynamic characteristic of underwater vehicle rotary motion, using the N-S equation turbulence model description of the steady rotation of the vehicle, this paper studies the numerical calculation method of aircraft rotating derivative underwater, using UDF programming to produce a stable pressure rotation the flow field, set up an numerical turning basin. Then based on the simulation analysis the influence of the different radius of gyration and different angle of attack on the vehicle motion.
Static Analysis of the Sub-Frame Based on Precision Load
Authors: Li Zheng , Wang Er Mao , Li Hai Gang
Published: October 2014

In this paper, strength analysis of the sub-frame of a heavy-duty dump truck was done based on ADAMS and ANSYS. A prototype model of dump system of dump truck was built basis of drawings and technical documents. The prototype model of dump system was imported into ADAMS, then driving and kinematic pair were created to form a complete prototype system. Force curve and force value of each key point in the sub-frame was obtained under unloaded condition by simulation of unloading operation. The results showed that the strength and stiffness of the sub-frame under pure bending condition and the initial stage of unloaded condition meet the requirements;In critical slipped stage of cargo, the maximum stress of the rear rotating shaft of sub-frame is greater than the yield limit of the materials, and its position is consistent with fault location in the practical application.
Research on Time-Domain Dynamic Response of Tension Leg Platform in Regular Wave
Authors: Liu Wei Min
Published: October 2014

Move performance in six-degree-of-freedom is one of the important indexes of hydro-dynamic property of tension leg platform (TLP). This paper discusses the time domain dynamic response characteristics of a tension leg platform in the regular wave. The paper focuses on the effects of the incident wave angles (15 °, 22.5 ° and 45 °), the wave height (6m, 8m and 10m) and the wave period (10s, 12s and 14s) on the movement of tension leg platform, the top tension of the tension leg. The results show that: because of the different sensitivity of the tension leg platform to the incident wave angle, the wave height and the wave period, the motion characteristics is different.
Optimization Design of Rapid-Cooling Mixer of By-Pass System of Cement Production Based on CFD
Authors: Mao Ya , Fu Wei , Chen Zuo Bing
Published: October 2014

In the situation that energy is increasingly grim, how to use high-sulfur fuel effectively and reasonably is a big problem for high-energy consumption cement industry. But high-sulfur fuel will also brought up crusting problem because of higher concentration of circulating and accumulating volatile components. By-pass system can resolve this problem. Rapid-cooling mixer is key equipment for by-pass system. The thermal flow field inside the mixer determines the performance of rapid-cooling mixer directly. CFD method is used to simulate the flow field and temperature field inside mixer. The simulation result help to guide and test the improvement of mixer structure design. After optimization structure design, the mixing of hot gas and cooling air is full and strong inside mixer that leads to excellent cooling effect and good protection for equipment from crusting.
Investigation of Material Behavior of TRIP Steel by Macro and Micro Multiscale Simulation
Authors: Li Jian Hui , Yu Zu Jian
Published: October 2014

Transformation induced plasticity (TRIP) steels is a kind of low-alloying high strength steel with good combination of strength and plasticity. To investigate the material behavior of TRIP steel, the multiscale simulation method was used in this paper. Through the investigation we can see that, multiscale simulation model of TRIP steel can be setup by combining finite element and microscope technology together, and the simulation results agree with the experimental results greatly. Both for uniaxial tension and biaxial tension, the micro stress distribution was unevenly for the difference of material behavior of bainite, ferrite and retained austenite, which create local stress concentration, and for uniaxial tension and biaxial tension, the stress distribution of biaxial tension was relative average, for the boundary condition biaxial tension was a kind of relative even boundary condition, the stress on different direction was balance.
Numerical Analysis of Sewing Air Floating Needle Bar Based on Slit Type Guide Rail
Authors: Zi Tong Jiang , Zhang Jun An , Lu Zhi Wei , Liu Bo
Published: October 2014

For the large air bearing capacity and high rigidity, the author put forward a kind of slit type guide rail which based on gas film clearance throttle,through establishing the guide physical model,fitting the gas film surface ,and building a flotation control equation, refering to the finite difference method and dichotomy,solved the gas film pressure distribution based on Matlab numerical calculation,analysed the bearing capacity of gas floating needle bar under different eccentricity and the stiffness.The results show that: the gas floating guide,if a slit’s width is 0.2 to 0.26,and the cumulative length of the slit for half of the perimeter of the inner surface,the slit intermittently arrange six along circumference,has the best static performance.The larger the needle bar eccentric,the bigger the flotation capacity and stiffness,it is capable of carrying the load of the needle bar,and the air tightness of the structure is good,throttling effect is obvious.
Optimal Design of a Hydraulic Suspension Mechanism of Aircraft Recovery Vehicle
Authors: Hong Zhen Yu , Zhang Peng Fei , Xu Zhi Hua
Published: October 2014

Through theoretical analysis of a suspension mechanism used for aircraft recovery vehicle, the mapping relationship between the hydraulic cylinder axial force and scale parameters of the suspension mechanism was built. With coordinate values of each hinge joint of the suspension mechanism in the initial position as design variables, the minimum hydraulic cylinder axial force was taken as evaluating index with reasonable constraints and optimal design of the hydraulic suspension mechanism was studied. The influence law of scale parameters to the axial force was discussed and coordinate alternation method was applied to find the optimal solution. The effectiveness of the method was indicated by an example.
A New ESO-Based Method to Find the Optimal Topology of Structures Subject to Multiple Load Conditions
Authors: Tumino Davide , Ingrassia Tommaso , Nigrelli Vincenzo
Published: October 2014

In the field of topology optimization problems, the Evolutionary Structural Optimization (ESO) method is one of the most popular and easy to use. When dealing with problems of reasonable difficulty, the ESO method is able to give very good results in reduced times and with a limited request of computational resources. Generally, main applications of this method are addressed to the definition of the optimal topology of a component subjected to a single load condition. In this work, a new methodology, based on the ESO approach, is introduced for the study of the optimal topology of a component subjected to multiple load conditions. The new procedure, entirely developed in the APDL programming language, has been tested with a holed plate subject to two different load conditions; the obtained results are promising in terms of mass reduction and structural performances.
New Method of Increasing Working Volume of a Certain Type of Hydraulic Accumulator
Authors: Ding Guo Bao , Shi Zhi Quan , Cui He , Huang Yong Sheng
Published: October 2014

This paper establish the function relationship between various parameters based on the study of the hydraulic pump and the dynamic characteristics. Through the establishment of transfer function is pull transform and the analysis of the characteristics of the transfer function of accumulator absorbing pressure pulsation actual effect. On the basis of further analysis, the improved method of effective volume of the accumulator, designed for fault detection and improve the system to provide a reliable basis.
Operation State Evaluation of Distribution Network Based on Attribute Mathematics
Authors: Cai Min , Chen Xing Ying , Liu Jian , Yu Kun , Chen Dan , Liu Yu , Zhang Wan Yue
Published: October 2014

Distribution network can implement self-healing when real-time operation state can be mastered comprehensively and operation change tendency can be predicted. Firstly the evaluation index system of operation state was constructed from five aspects (safety, reliability, quality, economy and adaptability). Then, distribution network’s operation network evaluation model was established on the basis of attribute mathematics theory, which could transform this problem into calculation problem of operation state’s attribute measure. Analytic hierarchy process was used to determine the weights of indexes. Finally the process for evaluating operation state was given. The simulation results show that this model can get accurate operation state of distribution network.
Design of Solar Tracker Based on Square Structure and Camera Device
Authors: Liu Yan , Liu Jian , Song Ying Wei , Zhao De Wei , Zhao Lin , Song Zhuo Ran , Wang Li Di
Published: October 2014

Solar tracker is an important part of photovoltaic generation and solar heating system. By solar tracker, the efficiency of solar utility can be significantly improved. Considering the camera device is widely applied in the photovoltaic generation and solar heating systems, based on the visual motoring equipment, a kind of solar tracker is designed. Using the proposed solar tracker, the height and the angle of the sun can be detected and be applied in solar tracker controller. Experiments show this design has relatively high accurate rate during a week’s period while the weather are partly cloudy or clear. It shows good application future in photovoltaic generation and solar heating industries.
Previous Research of Real Time Power System Dynamic Monitoring Master Station System Test Specification
Authors: Chen Li Jie , Guo Zi Ming , Zhao Kun , Zhang Hao , Yan Cui Hui , Yan Bo , Li Xin Peng
Published: October 2014

Phasor measurement technology developed rapidly in CHINA, Real time power system dynamic monitoring master station system were built widely in inter-regional power system and provincial power system, With WAMS system of practical ,WAMS master station test specification making is particularly important .The WAMS application ,series standard normative and the need to make a master station system test specification were described .According to the master system in the operation of the power dispatch center ,test content was put forward ,the content include Hardware requirements ,the system function and the application functions .At the same time ,protocol test method ,transmission delay test method ,data formats ,the test methods of system performance and application performance were proposed .Test content and methods research of real time power system dynamic monitoring master station system lay the foundation for the making of the master station system test specification ,provide reference for the development and practical use of real-time dynamic monitoring system.
Spatial Load Forecasting Based on Load Forecasting Reliability
Authors: Xiao Bai , Wang Hao , Mu Gang
Published: October 2014

A spatial load forecasting method based on reliability of load forecasting is proposed. It calculates the correlation of wave comprehensive index, variance, maximum predictable ability of each power supply small area’s historical load data by using the analysis theory of grey degree based on the analysis of load forecasting error last target year. The weight of each factor effected on prediction outcomes according to the gray correlation degree is determined, then the load forecasting reliability model of each power supply area is constructed. Finally, by using the adjustment role of load forecasting reliability, the load of target year is forecasted. Actual example shows that the spatial load forecasting method based on reliability of load forecasting is correct and effective.
Substation Locating Method in Integrated Relay Graph Splicing Based on Improved Genetic Algorithm
Authors: Gao Xu , Du Li Yan , Li Xue Dong
Published: October 2014

Distributed protection relay value setting is widely applied in china. There is a graph chaos problem in protection relay model splicing process. Deeply study the characteristic of integrated relay splicing, combined with the substation voltage level, a substation locating method based on improved genetic algorithm is proposed. To enhance the graph splicing, a voltage level based method is applied. At last, a practical example is used to validate the effectiveness of the method.
The Improved Five-Zone Control Theory with Considering Dynamic Reactive Power Compensation Device
Authors: Qi Lin E Ge , Liu Di Chen , Wu Jun
Published: October 2014

The “five-zone” control theory is a kind of Reactive power integrated control theory With the device as the control object directly which is different from the traditional “nine-zone” theory . It has high control precision and good control effect and has a broad application prospect. However, with the appearance of New type of dynamic reactive power compensation device, the basic five-zone control theory can’t meet the new demand In this paper, on the basis of the traditional "five-zone"theory, considering the dynamic reactive power compensation device, the traditional five area boundary is improved. Based on the improved chart on the basis of the five area, defines a new type of five area chart control method, and finally verifies “improved five-zone” control method by simulation.
Numerical Investigation on Transmission Line Conductor Icing
Authors: Yi Xian , Huang Han Jie , Zhou Zhi Hong
Published: October 2014

Ice accretion on transmission line conductor exists widely in nature, which can bring a lot of hazards. It is important and necessary to obtain characteristics of ice on different conductors for analyzing ice hazards or developing ice protection technology. A numerical method based on CFD technology for predicting ice accretion on transmission line conductor was presented in the present paper. Ice accretion on a conductor with a diameter of 26 mm was then predicted with the numerical method and an icing wind tunnel experiment. The results showed that it was acceptable to use clear cylinder as actual conductor for icing study, and the numerical results were credible. The effects of droplet diameter, liquid water content, air speed and time on icing were then investigated with the numerical method. The law that ice thickness, limit and volume varied with different icing conditions was obtained, which built a good foundation for further research.
Interference on Geoelectrical Resistivity Observation from DC Power Transmission Line
Authors: Wang Xiao Xue , Wang Ping Dong , Shi Lang , Rao Jian Lin
Published: October 2014

The interference on the geo-electrical resistivity observation from DC power lines is a key issue puzzling seismic monitoring. According to the working principle of geoelectrical resistivity observation instrument,the reason of interference on geoelectrical resistivity observation is analyzed.The calculation formulas of potential in soil, which is represented as horizontal two-layer electrical model, are derived by equivalent complex image method which responding to the ground electrodes of DC power line with various models: one vertical ground electrode, horizontal double-ring ground electrode and four vertical ground electrodes.In this way, the values of interference on geoelectrical resistivity observation from DC power lines under various situations are calculated and researched.The results show that the value of interference could be reduced 50% for horizontal double-ring ground electrode, and four vertical ground electrodes could be reduced 75%.
The New Methodology of Diagnosis for Transformer Inter-Turn Short Circuit Based on Wavelet Analysis
Authors: Quan Yu Sheng , Chen Ning , Wang Zi Jian , Shi Pu Xin
Published: October 2014

Based on the large number of experimental data analysis and processing, a new inter-turn short circuit transformer diagnostic methods is proposed. In this paper, take the grounding current of transformer core as the signal source. Using wavelet multi-resolution technology the signal wavelet multiscale decomposition, we can get high frequency components of the signal. Achieve short-circuit fault diagnosis between transformer winding turns by comparing the number of the high-frequency component contained in different signals in the decomposition of the same scale.
Analysis of the Sensorless PMSM Control Technique in the Full Speed Section
Authors: Li Hong Gang , Li Chao Feng , Zhao Rui Jie , Liu De Lin , Zhu Hong Hao
Published: October 2014

A novel position sensorless control strategy integrated with full section and high precision for a permanent magnet synchronous motor (PMSM) applied to wind power pitch was proposed in the paper. Based on high frequency signal, where three-phase triangular carrier spwm is injected and the state current response is detected to accurately estimate the rotor position in the still and low speed, which doesn’t rely on the non-ideal features. Based on BEF PMSM mathematic model, the phase locked loop technique is used to accurately detect the rotor position in the middle and high speed. the Finally, experiment on a 10 KW pith system demonstrates that the proposed method is effective and is capable of achieving more accurate control in the full speed section.
Design of Drive Circuit for Permanent Magnet Brushless DC Motor
Authors: Zhou Hong Mei
Published: October 2014

Based on the study on basic principle of rare earth permanent magnet brushless DC motor, the motor drive and protective circuit was designed in this paper. According to the work environment of brushless DC motor (BLDCM), the insulated gate bipolar transistor (IGBT) was chosen as a motor inverter unit core element, and IGBT special integrated drive chip VLA517-01R was used as the core to build IGBT driver protection circuit. High speed optical coupling isolation was used between drive circuit and control circuit, avoiding interference from drive circuit to the control circuit, ensuring the reliable operation of the system. Through the test it is proved that the designed circuit possesses good response, high stability, and when circuit fault happens it can reliably shut off IGBT output, feeding back fault signal.
Experiment Research on Five-Segment Type Space Vector Pulse Width Modulation for Permanent Magnetic Brushless DC Motor
Authors: Liao Zhi Ling , Cai Xiao Lei , Jia Hong Ping , Shi Wei Dong
Published: October 2014

Traditional square current driving method has deficiencies in muting and efficiency when controlling the brushless DC motor. This paper presents a method of space vector pulse width modulation for BLDCM, which is in five-segment type. A mathematical model of BLDCM, which is in d-q coordinate system, was established. Then, the experimental platform was constructed with the STM32F103 for BLDCM of electric vehicle. And the experiment results verify the properties of little torque ripple, smooth operation and low switching losses. Besides, the system dynamic and static performance is greatly improved, and has strong robustness. The method proposed overcomes the shortcomings of square current driving method in control efficiency and motor noise.
Lissajous Curve of an Auxiliary Winding Voltage Park Components for Diagnosing Multiple Open Switches Faults in Three Phase Inverter
Authors: El Menzhi Lamiaâ , Saad Abdallah
Published: October 2014

In this paper, a new technique for diagnosing multiple open switch fault in three phase voltage inverter feeding induction motor is presented. It is based on the so-called the Lissajous curve of an auxiliary winding voltage Park components. For this purpose, expressions of the inserted winding voltage and its Park components are presented. Simulation results curried out for non defected and defected inverter show the effectiveness of the proposed method.
The First Solar Power Tower System in Saudi Arabia
Authors: Abu-Hamdeh Nidal H. , Alnefaie Khaled A.
Published: October 2014

This article is about designing and building a small scale prototype tower system to gather solar energy and store it in a molten salt tank. The system consists of several heliostats directing incident solar rays to a receiver at the top of a tower. It is intended to establish highly reputable research and development facility in solar thermal energy systems. A thorough investigation in the field of building and utilizing solar tower system was conducted. The authors studied and presented the current state of art of the technological developments concerning the solar tower systems and an assessment of their advantages and disadvantages. The adaptability of CSP (Concentrating Solar Power) power systems to Saudi Arabia climate was closely investigated. A scheme for a pilot solar power plant that it most suited to the conditions of Saudi Arabia was proposed. The next stage will be building, fabrication, and constructing the various subsystems; heliostats, tower, receiver, and storage tank.
Calculating the Maximum Penetration Capacity of Distributed Generation Considering Current Protection
Authors: Wu Li Jie , Chen Xing Ying , Liu Jian , Yu Kun , Xu Shu Yang , Mo Fei
Published: October 2014

The different penetration capacity of various distributed generation (DG) in distribution network has important effect on planning and dispatching scientifically. The dynamic model of a small synchronous generator is established in this paper, and we figure out the maximum acceptable power of distributed generation for each node in distribution network considering reliability of protection electromagnetic transient simulation method, and the limiting factors are also analyzed in it. Finally, some methods are proposed to improve maximum penetration capacity, so it can provide reference for farther research of maximum penetration capacity in next stage.
Modified Suggestions for Distribution Automation Standards to Coping with DG Connected to the Power Grid
Authors: Jing Xiao Rui , Fu Qiang , Yang Bo
Published: October 2014

With the rapid development of energy-saving and environmentally friendly power sources, such as solar photovoltaic and biomass power, the demand of distributed generation (DG) systems connected to the low-voltage distribution network is increasing. Distributed generation systems connected to the low-voltage distribution network will impact power quality, security and stability operation of power grid. So power companies should strengthen the supervision of DG. Based on the research of domestic and foreign DG monitoring standards, this paper sorts out the DG relevant provisions in existing distribution automation standards, and proposes some modified suggestions in the existing distribution automation standards to cope with DG connected to the distribution network.
Rapid Double-Layer Identification Method of Multi-Relevant Bad Data in Large-Scale Power Grids
Authors: Kun Zhao , Ying Xing , Xu Jie , Zhang Yin , Lei Yan , Dong Xing
Published: October 2014

Bad data detection and identification is an important part of state estimation. When the relevant bad data appears, however, there is residual pollution and residual submerged condition in currently available methods of bad data detection and identification. In view of the above problem, this article presents a double-layer bad data detection and identification technique. At first, it is based on regularization residual detection method (Rn detection method) to identify the suspect measurement sets. And then, it presents a fast search technique of interrelated suspect measurements to search interrelated measurements in all the suspect measurements of the entire power grid and produce interrelated suspect measurement sets. Furthermore, use double-layer identification method to fast identify the bad data in interrelated suspect measurement sets, in other words, identify all the bad data in entire power grid. At last, taking IEEE39 node power grid for example, this detection method of bad data is analyzed, the accuracy and effectiveness of this method is to be verified.
Research Status of Key Technologies of Seamless Switching in Micro-Grid
Authors: Xi Guan Nan , You Wei , Wang Chuan Xing , Yuan Yin Nan , Qian Yong Ming
Published: October 2014

In allusion to the stability of transferring between grid-connected and off-grid state in micro-grid, this paper introduces the seamless switching technology, analyzes the key technologies of seamless switching and the existing problems, and gets the conclusion about research status of seamless switching.
Research on Supporting Role of Smart Grid in Wisdom City
Authors: Meng Lu , Wang Wei , Wang Yun Long , Wang Qian
Published: October 2014

With new technology, Wisdom City makes the various functions of the city in coordination with each other. It provides high quality development space for enterprises and high quality of living for citizens. As an important part of Wisdom City, Smart Grid can ensure the safety of electricity consumption, improve the urban communication network and promote the city green development and industrial development, etc. This paper analyzes the supporting role of Smart Grid in Wisdom City top design, data mining, communication resources, policy system, business model and evaluation index, etc.
Micro-Grid Energy Optimization Include Battery-Swapping-Station
Authors: Shu Liu , Liu Fang , Yang Xiu
Published: October 2014

Accessing electric vehicle (EV) into micro-grid (MG) by battery-swapping station (BSS) will not only reduce the negative impact brought by EVs which are directly accessed into MG, but also improve the capacity of MG to absorb more renewable energy. That BSS is regarded as schedulable load is guided to avoid peak and fill valley according to TOU. As a result, the gap between peak and valley of MG is decreased and the operation efficiency of MG is elevated. A specific MG is taken as the studying object and the minimum operating cost is regarded as the optimizing goal, then the genetic algorithm is used to optimize the outputting of each micro-source and the charging power of BSS so that the optimal operation is realized.
The Implementation Pattern of Smart Distribution Grid and Utilization
Authors: Xu Shi Ming , Liu Yu , Chen Xing Ying , Huang Li , Yang Yong Biao , Yu Kun , Liao Ying Chen
Published: October 2014

Smart Distribution Grid and Utilization are the important support for the development of Smart City and Smart Grid, meanwhile, the effective data communication and information exchange are the key points to implement them. First, analyze the unified communication method of Smart Distribution Grid and Utilization for each specific business. Then, respectively, from the current reality and future trends, propose two typical implementation:the interface adapter pattern and the integrated pattern, and establish specific implementation patterns, deployment patterns, and pattern evaluations, so as to provide the design of pattern level for the development of Smart Distribution Grid and Utilization.
Analysis of the Characteristics and Effects for Sichuan Province Electric Power Consumption
Authors: Chen Ce , He Xing Qi
Published: October 2014

Using data from 2007 to 2011 as the sample, on the base of analyzing the power consumption overall situation of Sichuan Province, the effects of Sichuan electric consumption, energy consumption characteristics factors, increase the proportion of the reasons were studied. The research results to improve the operation quality and efficiency of management, further develop the electric power market has a certain reference value.
Study on the Theoretical Basis of Power-Grid Crisis Management
Authors: Li Shi Hua
Published: October 2014

Power grid crises at home and abroad happened frequently, insufficient research on power grid crisis management and awareness of “crisis and crisis management” warns the necessity and urgency of power grid crises management. Necessity of finding rational theoretical basis for our studying crisis and carrying out crisis management are becoming urgent. This article proposes the theoretical basis from three aspects: stage-division theory, system theory and structure theory. Stage-division of power grid crisis management can be adopted according to practical study. The outstanding performances of all components of crisis management embody the safe and stable operation of power system. Fragmentation of thinking way in power grid crisis management will hamper the crisis management, and we should establish “systems thinking”- “to see the whole”.
Bio-Oil Production from Fast Pyrolysis of Corn Stalk in a Fluidized Bed
Authors: Fu Peng , Li Zhi He , Bai Xue Yuan , Yi Wei Ming
Published: October 2014

Fast pyrolysis of corn stalk was performed at temperatures in the range of 450 - 600 °C in a fluidized bed. The chemical composition of bio-oil was analyzed by GC–MS, and its main properties were determined. The results showed that the bio-oil yield increased with increasing pyrolysis temperature from 450 °C to 500 °C and then declined with a further increase in pyrolysis temperature. The highest bio-oil yield of 43.3wt% was obtained at 500 °C with the dolomite as bed material. The char yield always decreased with the rise of temperature. The major chemical compounds of bio-oil included hydroxyacetone, butanone, acetic acid, propionic acid, ethylene glycol, phenol, etc.
Numerical Simulation for Heat Transfer and Fluid Flow Performances of Thin Film Evaporation in the Micro Rectangular Groove
Authors: Dong Jing Ming , Kang Chun Lu , Yuan Hai Chao , Pan Xin Xiang
Published: October 2014

The heat transfer and fluid flow performances of thin film evaporation were investigated numerically in this paper. Based on the coordinate transformation and the Galerkin Method, the analytical solutions of the temperature and pressure distribution within the meniscus bulk region, where the interface is dominated by surface tension were found. The effects of contact angle, superheat and aspect ratio on the temperature distribution of thin film evaporation in the rectangular groove were studied. Meanwhile, the pressure and velocity distribution of thin film evaporation were calculated and analyzed. The results had investigated in this paper can help understanding the mechanism of thin film evaporation for the further study.
Simulation Investigation on Structural Parameter of Hot Air Igniter of Biomass
Authors: Cui Yong Zhang , Tang Ming Tian , Zhang Lin Hua , Gao Peng , Zhang Guo Kai
Published: October 2014

In view of rich resources of corn stalks, cotton stalks forming pellets hot ignition performance, using CFD numerical simulation analysis to study the key parameters of electric ignition such as the surface ignition temperature, air velocity, air flow distribution ratio of influence of hot air outlet temperature. Obtained that increasing electric heating surface temperature, reducing the air flow velocity and convective heat transfer coefficient of the outer tube can significantly improve the ignition temperature of the outlet hot air, the outlet hot air temperature should be higher than 450 °C. Ignition internal and external air passage area ratio affects the allocation of hot air flow, the best area ratio of between 1.8-2.2.
Test and Research for Mercury Emission of Boilers in 700 MW Units
Authors: Liu Fa Sheng , Zhong Yong Lu , Xu Rui , Chen Lin Guo , Xia Yong Jun
Published: October 2014

In this paper, the conversion process and the existing forms of mercury in the course of coal firing are first analyzed, and different methods to measure mercury are introduced; To assess the mercury emission levels of boilers in large power plants, through testing the mercury content in combustion products of the boiler in 700 MW unit under different loads in one power plant of Jiangxi Province, we analyzed the formation distribution of mercury emissions and the effect of low temperature economizer on the mercury concentration before and after the ESP, and acquired the mercury emission characteristics of 700 MW boiler. In study, we found that mercury in the coal burnt in 700 MW boiler was mainly discharged in the form of gas, with a small amount existing in burnt solids. The change of gaseous mercury before and after the ESP is not obvious, but the concentration of bivalent mercury is higher than that of zero-valent mercury; and more than 90% of the particulate mercury is removed. The low temperature economizer in operation can obviously reduce the concentration of mercury in flue gas at the ESP outlet by 30.8%.
Numerical Simulation Analysis of the Optimized and Transformed 200MW Pulverized Coal Fired Boiler Burner
Authors: Lv Tai , Zhao Shi Ze
Published: October 2014

With the use of computational fluid mechanics software – FLUENT, the numerical simulation computation of combustion process inside a certain 200MW corner tangential firing boiler whose combustor is transformed by the multi-grade efficient low-nitrogen combustion technology was conducted, thus the furnace temperature, velocity, mixture and NOx concentration field at rated conditions before and after the transformation were obtained. The calculation results were highly identical with the industrial test results. The results show that after using the multi-grade efficient low-nitrogen combustion technology, the NOx emissions significantly lowered down with the drop of about 40% compared with the emissions before transformation, while the furnace coking and high temperature corrosion were effectively controlled, achieving good economic and social benefits and providing a reference to the design and transformation of the same types of boilers.
Based on Concept of Generalized Instantaneous Space of Dynamic Performance Analysis
Authors: Liu Ao Xiang , Wang Jun , Kang Jun Xian , Zhang Qiang , Sun Jun , Shu Qi Lin
Published: October 2014

TX1600 boring and milling machining center milling part was studied. The Three-dimensional solid model was established based on Solidworks. Simultaneously, modal analysis was carried out by ANSYS Workbench software, the first six natural frequencies and corresponding modes were acquired. Based on the modal analysis, the harmonic response analysis of milling part was conducted,and the response curves of the three main motion orientation were obtained respectively, the vibration performance of milling part under forces was further explored,and the finite element model was validated. The feasibility of the model to simplify the program was verified by modal and harmonic response analysis. The study provides a good basis in terms of selecting a specific material. The structures and material are optimized. Ultimately, a lot of energy is saved.
Finite Element Analysis of Large-Size Yaw Bearings with Supporting Structure in Wind Turbine
Authors: Shang Zhen Guo , Ma Zhong Chao , Sun Zhen Sheng
Published: October 2014

A procedure for obtaining the load distribution in a four point contact wind turbine yaw bearing considering the effect of the structure’s elasticity is presented. The inhomogeneous stiffness of the supporting structures creates a variation in the results obtained with a rigid model. A finite element model substituting the rolling elements with nonlinear compression springs has been built to evaluate the effect of the supporting structure elasticity on the contact forces between the rolling elements and the raceways.