bluuebunny/crossref_metadata_2025 huggingface dataset:
Optimization Scheduling of Cascade Hydropower Stations in Energy Conservation and Emission Reduction
Authors: Li Ze Hong
Published: August 2013

Considerable water saving and electricity can be attained by optimal regulation of cascade hydropower plants, equivalent to building large and medium-sized hydropower stations without increase in investment and immigration. Thus, the optimal regulation of cascade hydropower plants has great significance on increasing the consumption ratio of fossil energyand reducing atmospheric pollutants discharge. Taking Wujiang river basin as an example, mathematic models and rules of optimal regulation have been obtained in the research,Automation systems have been developed, forming an integrated work platform. Combining optimal regulation and generator control together, the platform helps to put scientific method into practice.Electricity 585 million kWh has been obtained through optimal regulation of Wujiang cascade hydropower stations per year on average, 162200 tons of coal can be saved annually,reduce coal burned by thermal power plants.about 474900 tons of Carbon dioxide, 3185 tons of Sulfur dioxide,3012 tons of nitrogen oxides can be reduced every year.
A Stochastic Programming Method for Unit Commitment of Wind Integrated Power System
Authors: Shao Jian , Zhang Bu Han , Deng Wei Si , Zhang Kai Min , Jin Bing Jie , Ge Teng Yu
Published: August 2013

This paper presents a stochastic programming method that can assess the impact of wind generation uncertainties on unit comment (UC) problem. To model the uncertainty of wind genration, scenarios of wind speed are generated based on the known probability interval of forecasted wind speed and a scenario reduction technique limits the number of scenarios. The UC problem is modeled as a stochastic programming problem based on chance-constrained programming, and is decomposed into two embedded optimization sub-problems: the unit on/off status schedule problem and the load economic dispatch problem. Discrete particle swarm optimization (DPSO) and the equal incremental principle are used to solve the stochastic UC problem. The numerical results indicate that the proposed stochastic model is more suitable for wind integrated system with uncertainty.
Demand Side Response Based on TOU Price and Economic Compensation
Authors: Niu Dong Xiao , Song Yuan Lin , Lu Yan , Mei Lin
Published: August 2013

Demand-side response allows electricity users to actively participate in load management and to solve the problem of electricity supply shortage. This paper studies the model of demand-side response based on TOU price and economic compensation, the impacts on avoidable load and transferable load are respectively studied. Then, the summer load situation of a company is taken as an example, the sensitivity of each factor are also analyzed, so as to achieve the result of load shifting and promote the stable operation of the grid.
System Dynamics Model about the Mode of Energy Transmission
Authors: Yang Shu Xia , Han Qi
Published: August 2013

With the rapidly growing economy, the energy demand increases greatly. Due to energy distribution imbalance in the space, part of the areas lack of energy resources, relying on energy call to ensure energy security. In this paper, first of all, we put forward the steps of comparatively studying different modes of energy transmission with system dynamics model and carry out a causal analysis. Then we analyze the causality among model variables. Finally, we draft a causality diagram of model elements. Based on this, we establish quantitative relations among variables and draft a system flow diagram.
A Power Quality Monitoring Data Management Scheme Based on Distributed Database
Authors: Zhang Qing Qing , Wang Qing Yu , Zhang Gao Feng , Zhang Yi , Wu Lan Xu
Published: August 2013

Currently the massive power quality monitoring data are stored in the centralized database of the monitoring master station, the problems such as large storage space; low query retrieval speed; low reliability and poor scalability will be caused. This paper proposes a data management scheme for massive power quality monitoring data based on the distributed database system. The monitoring data of different power quality indexes are stored in the distributed servers of the existing monitoring sub-stations; the server of monitoring master station is used for storing data characteristics value and data indexes, it is also used for unified management of distributed database system. The scheme takes full advantage of each servers storage space and network bandwidth, and saves the storage space and improves the access efficiency.
Forecast of Power Quality Index Based on the Discrete Fourier Decomposition and AR Model
Authors: Wen Cong Xi , Gao Shan , Xiao Xiang Ning , Xu Yong Hai , Tao Shun
Published: August 2013

A method of autoregressive (AR) based on discrete Fourier analysis is proposed to forecast the indexes of unbalance factor and total harmonic distortion. The discrete Fourier transform of the index sequence is analyzed and the low frequency components are extracted. Autoregressive method is applied to forecast each low frequency component. Through inverse discrete Fourier transform, the forecasting low frequency components are inverted to forecasting sequence of the index in time domain. Actual data is used to test this method and the results show that discrete Fourier analysis is possible to reduce the influence of high frequency noise and that the AR method based on Fourier transform can effectively forecast the indexes of unbalance factor and total harmonic distortion.
Interruptible Load Risk Analysis Based on Portfolio Theory
Authors: Wang Jin Feng , Zhu Rong , Jiang Yan
Published: August 2013

Due to the uncertain price and stochastic load, power supply companies will face the trade-off between profits and risks when exercising Interruptible Load Management (ILM). Customers of different type are looked as sub-markets with different risk and benefit. A model is established for Interruptible Load (IL) in the framework of portfolio theory, with the object of maximizing the expected profits and risks of conditional value at risk (CVaR). Genetic Algorithm (GA), is adopted to solve the model. Finally, a numerical example is served for demonstrating the market property of high profits accompanied by high risks and the feasibility of the proposed model, thus a reference is provided to a power supply company to manage risks.
Reactive Power Compensation for Unbalanced Fluctuating Loads by Using Two-Dimensional Instantaneous Space Vector Approach
Authors: Wu Chi Jui , Liu Yu Wei
Published: August 2013

To improve the power quality and efficiency on feeding unbalanced loads, this paper proposes a scheme of instantaneous current compensation that can modify the power factor and balance the three-phase currents simultaneously. The method of instantaneous space vectors can compensate the reactive power effectively, but the problems of unbalanced load currents remains. This paper suggests a method that can mitigate the unbalanced load currents by setting the active power as a constant for each cycle. Field measurement data were analyzed. Simulation results confirmed the feasibility of correcting the power factor and balancing load currents simultaneously using the proposed method.
CFD Design and Analysis on Circular Slotted Fin Surfaces of Two-Row Tubes Heat Exchangers
Authors: Zhang Jing Zhao
Published: August 2013

A numerical investigation of the flow and heat transfer in a two-row finned-tube heat exchanger is conducted with a three-dimensional conjugated model using the CFD software. The results show that, compared to the quadrate slotted fin, the circular slotted fin have good heat transfer performance in that the percentage increase in heat transfer is higher than that in the friction factor. Within the Reynolds number range compared ( from 1,270 to 8,892), the Nusselt number of new slit 1 is about 25.6-61.6% and 20.8-57.5%, while new slit 2 is about 26.8-33.6% and 25.8-33.0%, higher than that of the quadrate slotted fin surface at identical pressure drop and the identical pumping power, respectively. For the two-row plate fin-and-tube heat exchanger, new slit 2 is recommended for the use in air-conditioning because its integrative design.
Influence of Boiler Combustion Adjustment on NOx Emission and Boiler Efficiency
Authors: Zhang Bu Ting , Wang Chun Yu , Qin Qi , Li Ling
Published: August 2013

A tangentially fired boiler with twin furnace is tested to analyze the effect of such factors as primary air velocity,air distribution mode, over fired air,oxygen content on NOx and boiler efficiency during boiler combustion adjustment,providing reference for boiler operation optimization and reducing NOx emissions.
Influence of Parameters of Insulation Layer on Performance of Vacuum Heat Insulation Oil Pipe
Authors: Wang Zhong Hua
Published: August 2013

Influences of void ratio of glass fiber cloth, conductivity of glass fiber cloth, number of of insulation layer and emissivity of aluminium foil on apparent heat conductivity of vacuum heat insulation oil pipe are calculated based on the experiment plat in master machinery plant of Liaohe Petroleum Exploration Bureau. The results show that apparent heat conductivity of vacuum heat insulation oil pipe is inverse ratio to void ratio of glass fiber cloth, and is proportional to conductivity of glass fiber cloth and emissivity of aluminium foil. At vacuum condition, 6 layers is appropriate.
Numerical Research on the Drying Process of Single Lignite Particle by High Temperature Flue Gas
Authors: Dong Ai Xia , Zhang Shou Yu , Guo Xi , Zheng Hong Jun , Deng Wen Xiang , Lu Jun Fu , Shi Da Zhong , Dong Jian Xun
Published: August 2013

The technology of downstream vibrated bed dryer with high temperature flue gas has been applied successfully by CPI Mengdong Energy Group Co., LTD for the large scale upgrading of Baiyinhua lignite. It is very necessary to study the drying process of a single lignite particle by high temperature flue gas. Based on finite volume method, the numerical simulation was applied in the lignite drying process and the mathematical model for the drying process of a single spherical lignite particle with high temperature flue gas was developed. Here, the lignite particle was divided into dry region and wet region by water evaporation interface. To accelerate convergence and make stable domain larger and truncation error smaller in the solution process, Crank-Nicolson six-point difference iteration method was used to solve the model.
Numerical Simulation of Internal Fire Whirls in an Inclined Shaft
Authors: Huo Yan , Gao Ye , Huang De Xiang
Published: August 2013

In order to understand the characteristics of fire whirls in the inclined shaft with corner gap, large eddy simulations (LES) of thermal flow field in a 9-meter-high inclined shaft were employed. In the inclined shaft, the conrner gap is 0.3m and 0.7m in width, and the inclination angle is 5°, 30°, 45°, 50° and 55° from the vertical orientation axes respectively. It is found that a whirling flow field could be formed under proper inclination angles and corner gap width. Rotational axis of fire whirls in the inclined shaft would have same inclination angles with the shaft. Similar to the case of fire whirls in a vertical shaft, the width of corner gap of inclined shaft also influences the whirling motion of the flame. In this paper, for the same fire and inclination angle, the 0.3-meter-wide corner gap is easier to form stable fire whirls than the 0.7-meter-wide corner gap. By comparison with buoyancy, the slightly greater Coriolis force was found above a height 3m for inclined fire whirls when the width of croner gap is 0.3m, however, the Coriolis force acts only on the lower part of the shaft when the width of croner gap is 0.7m.
On Application of Looped Pulsating Heat-Pipe in High-Power LED for Street Light
Authors: Tang Wen Wu , Kou Guang Xiao , Hu Liang Liang , Zhou Hui Wen , Feng Bo
Published: August 2013

The ANSYS-ICEPAK is used to establish and analyze the thermal condition of the cooling modular of the looped pulsating heat pipe in the street light, the reliability is proved by experimental results of thermal analysis. The experimental results show that: the temperature distributions on the surface of the lamp shell and loop heat pipe are uniform, and the average temperatures of them are about 40°Cand 43°C; while the maximum temperature of the chip base reaches 67.5°C. Through comparison, the simulation results are close to the actual measured results.
Research on Aerodynamic Characteristics of Air-Cooled Turbine Blade with Conjugate Heat Transfer Method
Authors: Zhang Jing Jing , Wang Lian Fu , Fang Xiang Jun
Published: August 2013

In order to improve the performance of aero engines, trying to increase the turbine inlet temperature is an important way. But the turbine inlet temperature of modern aero engines can be more than 2000 K, which is far more than what the materials can bear. So advanced cooling technologies should be introduced to solve this problem. Using the conjugate heat transfer method, this paper researched the aerodynamic characteristics of a certain turbine blade with complex cooling structures. Some conclusions can be drawn: the velocity of the air flow and different distributions of coolant flow for turbine blade with multiple cooling air inlets have great influence on the cooling effect; the cooling effect decreases as the temperature ratio decreases; with the same mass cold gas, the less film cooling holes, the worse cooling effect; therefore, a reasonable air flow distribution plays an important role in obtaining good cooling effect.
Research on Coordinated Control System for Boiler-Turbine Units Based on Fractional-Order Control
Authors: Wang Li , Li Jian Jun , Wang Ying Hui , Guan Qing Xiang
Published: August 2013

It is important for conventional thermal power units to participate in frequency adjustment and peak regulation for the safe operation of grid side. This paper research on coordinated control system (CCS) for boiler-turbine units based on fractional-order control (FOC). The realization of fractional-order PID (FOPID) controller in distributed control system (DCS) is provided. The engineering application results show that this algorithm is easy to be realized in project by applying all sorts of existing algorithms in DCS. Furthermore, this algorithm can overcome the large lag and inertia for boiler and improve the primary frequency and automatic generation control (AGC) tracking performance in boiler-turbine CCS effectively.
Study on the Contamination Coefficient of Convective Heating Surface in a Circulating Fluidized Bed Boiler
Authors: Wang Yu Zhao , Liu Xue Min , Liu Ai Cheng , Liu Qing , Zhang Jian Chun , Jiang Wen Bin
Published: August 2013

The ash deposition and the gas velocity affect the exhaust gas temperature of a CFB boiler. The surface contamination in a CFB boiler is quite different from that one in the pulverized coal boiler. It is suggested that the surface contamination in a CFB boiler should be determined according to the ash content in the fuel as well as the cyclone collection efficiency. The effect of the gas velocity on the surface contamination is very important. The lower gas velocity causes more serious contamination, leading to the higher exhaust gas temperature. The staged tube arrangement should be employed. And the gas velocity should be designed higher to enhance the self-cleaning ability. Anyway, the soot blower should be designed in the CFB boiler convective heating surface. The ratio of the practical contamination coefficient to the design one, k,is the strong function of gas velocity, wy, which was expressed as: k=1+exp(6.8-wy)
The Experimental Research on Instantaneous Efficiency of PV/T Module Based on Micro Heat Pipe Array
Authors: Quan Zhen Hua , Wang Lin Cheng , Zhao Yao Hua , Deng Yue Chao , Wang Gang , Liu Hui Min
Published: August 2013

A novel photovoltaic /thermal (PV/T) module is invented, which use micro heat pipe array (MHPA), a flat heat pipe, to cool the solar cell. The PV/T module can achieve the purpose of cogeneration by collecting and utilizing waste heat while cooling the solar cell and improving power efficiency. In order to test the performance of PV/T module based on MHPA, instantaneous thermal efficiency test was performed. The intercept of measured instantaneous thermal efficiency curve can reach 41.4%, the slope is 3.95. The temperature of PV module is the key factor of the influencing electric efficiency. The PV/T modules electric efficiency is kept between 10.5% and 12.3% during the test. Solar energy utilization total efficiency at 20°C inlet temperature can reach more than 50%, and comprehensive performance efficiency can reach above 70%.
Calculation of the Remaining Life of Corroded Tan
Authors: Wang Ai Fang , Li Qun , Liu Xiu Lian , Wang Hong Guang
Published: August 2013

Because it is difficulty to collect field corrosion data,estimation of the remaining life of corroded tanks mostly adopts qualitative analysis. On the basis of the relationship curve of the corrosion depth and service time,according to the acquisition of corrosion data sample size,the paper used limited polyline to replace the corrosion curve,simplified the calculation of the remaining life of corroded tanks.
Analysis on the Mixing Process in a Heavy-Duty Diesel Engine under Different Conditions of Spray Position
Authors: Yuan Ye , Li Guo Xiu , Yu Yu Song , Xu Yang Jie
Published: August 2013

In order to investigate the influence of spray position on fuel air mixing quality, three-dimensional numerical simulation of the working process of a heavy-duty diesel was conducted. To quantitatively study the mechanism of the effect of spray position on fuel air mixing process, the deviation of spray centroid was introduced to describe the spray position change in combustion chamber. The results show that the gas intake swirl can affect the spatial distribution of spray in combustion chamber under three directions in cylindrical coordinate, in which the circumferential distribution is affected most. It then can be concluded that the spray can be limited to the vicinity of the combustion chamber axis. Better spray position, which is more helpful for the process of fuel air mixing and combustion, can be achieved by using optimal swirl, so that the power performance will be improved.
Multi-Objective Optimization Design of Screw Conveyor Using Genetic Algorithm
Authors: Wang Duan Yi
Published: August 2013

The weight minimum and drive efficiency maxima1 of screw conveyor were considered as double optimizing objects in this paper. The mathematical model of the screw conveyor has been established based on the theory of the machine design, and the genetic algorithm was adopted to solving the multi-objective optimization problem. The results show that the mass of spiral shaft reduces 13.6 percent, and the drive efficiency increases 6.4 percent because of the optimal design based on genetic algorithm. The genetic algorithm application on the screw conveyor optimized design can provided the basis for designing the screw conveyor.
Screw Expander for Waste Heat Utilization in Heating Furnace
Authors: Lu Yan Hong
Published: August 2013

According to the actual situation of heating furnace in Tianjin Tiangang United Co. Ltd, we designed a scientific and feasible solution of screw expanding power generator and auxiliary facilities matched, realized waste heat utilization of low-quality heat source from iron and steel industry exhausted, analyzed energy saving and environmental protection social benefit and good economic benefit that this solution have.
Multifunction Expansion Design of the Wellbore Multiphase-Flow Experimental System
Authors: Liang Hui Rong , Xu Jian Ning , Zhu Duan Yin
Published: August 2013

In this paper, a set of wellbore multiphase flow experimental system with several functions is designed. The system can complete a flow loop of the two-phase flow or the multiphase flow of oil, gas, and water in a level, vertical or tilt angle tube, used to study the flow law of these different mixed modes in the inner tube and the annular space of the wellbore and the heat transfer law between the fluids in the inner tube and the annular space. It is a set of large-scale and complete experimental system to research the multiphase flow.
Parametric Study of Crowned Blade in Horizontal Axial Turbine
Authors: Zhou Jun Wei , Wang Da Zheng
Published: August 2013

The horizontal axial turbine could extract kinetic energy from both wind and tidal stream. In this paper, a type of horizontal axial turbine was designed with a crown stalled on the blade tip and the turbine was analyzed in a tidal stream. Several turbines with different geometries of the crowns were compared, whose power coefficients were numerically simulated by the CFD method. Effects of the crown design parameters, such as crown setting directions and different widths on turbine efficiency were discussed. Furthermore, when the turbine worked at different tip speed ratio, the results were discussed, either. By analysis of the results, it is could be concluded that a circular crown was sufficient to eliminate blade tip loss caused by tip leakage flow. The upstream semicircle crown modified the corresponding side foil pressure distribution to the design value, and so did the downstream semicircle crown. In the ellipse crowns testing, turbine efficiency was approximately in line with the value of crowns width. When the turbine with the circular crown worked at a little higher tip speed ratio than the design value, the crown was effective as before.
Turbulent Characteristics of the Stratified Flow in the Braided River with Two Symmetrical Anabranches
Authors: Gu Li , Hui Hui , Hua Zu Lin , Li Qiu Lan , Jiao Zi Nan , Yan Ming
Published: August 2013

The turbulent characteristics of stratified shear flow in braided rivers have not been known until now. The physical model experiment was conducted to study the turbulence kinetic energy distribution of stratified shear flow in the typical braided rivers with a mid-bar between two symmetrical anabranches. Firstly, the distributions of depth-averaged turbulence intensity components in different sections of the anabranch were analyzed. The turbulent intensity peak occurs at the boundary of the separation zone near outer bank and the high velocity zone near inner bank in the entrance region of the anabranch. In the outlet section of the anabranch, turbulent intensity increased at the inner bank. Secondarily, Lateral-averaged turbulence intensity components were compared between different sections. There was obvious high turbulence appearing at the interface of hot and cold water in the inlet section of the anabranch. Finally, the distributions of total turbulence intensity were analyzed by the sectional contours.
Research on NOx Concentration Field Distribution of a Turbo-Jet Engine Emissions
Authors: Wang Qi , Ma Yun Feng , Hu Xiao Min
Published: August 2013

Along with the development of aviation industry, airplane emission pollutants is becoming more and more serious environment problem. All the pollutants of aero engine emission, the airplane and engine manufacture companies ,Airlines and environment protection departments care about most is how to reduce the NOx emission. In order to get the concentration distribution diagraph of NOx emission, a test-bed was constructed, the test-bed is designed of two test sections in emission pipeline, there are 13 sampling point in each section,3 test conditions selected to simulate different flying condition. The emission pollutants is monitored by Testo350,and the monitor results is analyzed by Fluent software to get the NOx concentration field distribution characteristics of a certain type of turbo-jet engine emission.
Integration of Multiple in-House Heat Stations into One Energy Flexible Heat System - Part 2
Authors: Riise Raymond
Published: August 2013

Integration of several in-house heat stations containing of multiple boilers of different capacity and energy carriers can be economical profitable. This study contains further analyze and development of previous work by Riise and Sørensen [1-3]. Boiler start-up costs effect of the overall energy cost has been investigated and found to have an impact of boiler configurations in a system based on lowest specific running energy cost. A study of operational hours of boilers indicates if boilers can be dismounted form the integrated system. It is also performed simulations for lowest energy consumption instead lowest energy cost. Finally a heat pump model is introduced and analyzed. Introduction of the heat pump reduces the total energy cost even if the heat sink is increased with a fourth building.
Application Study of Cold Air Distribution System
Authors: Zhang Xiao Ming , Sun Cheng Cai , Zhang Xiao , Li Ji Zhi
Published: August 2013

This paper briefly introduced the cold air distribution system principle and characteristics. Apply the simulation software to simulate air distribution and thermal environment of cold air supply room. Adopt Effective Draft Temperature (EDT) and Air Diffusion Performance Index (ADPI) to evaluate indoor thermal comfort.
Experimental Study on Heat Transfer Characteristics and Pressure Drops for Water Flowing in Spiral Coil Heat Exchanger
Authors: Zhang Xiao Yan , Jiang Fang Fang , Zhao Shan Yuan , Tian Wen Fei , Chen Xiao Hang
Published: August 2013

The heat transfer and pressure drop characteristics for water flowing in four spiral coils with different shapes and different sizes were experimental studied. Reynolds number range from 4000 to 9000, volume flow rate range from 200 to 350 L/h and heating power range from 80-350 W. Based on the experimental results, the regularity of Reynolds number and heating power influencing on heat transfer and pressure drop characteristics was analyzed and discussed. The results indicate: the Nu increases with increasing Re, the greatest average heat transfer coefficient appears in the smaller circular spiral coil. The heat transfer coefficients increase with increasing heating power, the greatest average heat transfer coefficient also appears in the smaller circular spiral coil. The pressure drops increase with increasing Re, the pressure drop in big ellipse spiral coil is greatest. The resistance coefficients gradually decrease with increasing Re. The resistance coefficient of small circular spiral coil is always greatest, and the resistance coefficient of big circular spiral coil is smallest.
OLTC Voltage and Reactive Power Control in Area Transmission System for Improvement Line Loss and Voltage Variation
Authors: Chuang Yung Sung , Lee San Yi
Published: August 2013

Coordination on load tap changers (OLTCs) voltage and reactive power compensators in area transmission power system is presented to improve efficiency and voltage variation using a novel optimum procedure technique. The novel optimum technique procedure used hybrid differential evolution (HDE) to coordinate the OLTCs setting and reactive power compensation for reducing line losses and voltage change rate. The objection function is selected total line loss under the limited range of OLTCs setting and reactive power compensation. The proposal design method is used to IEEE-30BUS power system to demonstrate the useful method. The result exhibits to less line losses and a little voltage variation.
A Novel Method of Static Security Analysis Based on Multithread Technology
Authors: Tang Bi Qiang , Yu Yi Jun , Feng Shu Hai , Li Feng
Published: August 2013

With the UHV (Ultra High Voltage) power grid construction and the interconnection of regional power grids, the scale of power grids in China is increasing rapidly. At the same time, significant uncertainty and variability is being introduced into power grid operation with the integration of large-scale renewable energy in power systems. All of these pose an enormous challenge to the operation control of power systems in China. For a long time, online static security analysis, as an important part of EMS (Energy Management System), has been an effective tool for power grid operation. However, it is increasingly difficult for traditional static security analysis in serial computing mode to be online applied in bulk power grids in China. A new practical parallel approach for online static security analysis is put forward in this paper. A multithread parallelism is introduced into contingency screening, detailed contingency evaluation and decision support for reducing the execution time. By employing the multithread technology, the hardware resources of multi-processor/multi-core computer can be fully used and the program can be speeded up effectively. The performance of the parallel static security analysis is demonstrated by tests on two large-scale power systems. The test results show that the proposed method can be online applied in real bulk power grids.
Distribution System Restoration Based on Hybrid Particle Swarm
Authors: Tang Li Zhi , Du Jun , Xu Kun Peng , Qi Xue Qing
Published: August 2013

By the heuristic algorithm and particle swarm optimization algorithm combining hybrid particle swarm algorithm proposed combination of heuristic search and stochastic optimization,stochastic optimization process using a spanning tree and the loop matrix operations combined to ensure the system topology constraints to improve the efficiency of solution. The analysis shows that the proposed method calculation speed,easy to converge to the global optimal solution. It can effectively solve the problem of distribution network fault recovery.
Fast Static Security Analysis of Day-Ahead Generation Scheduling 96 Period Cases Adapting to Large Power System
Authors: Li Feng , Wang Zhi Hua , Li Hu Cheng
Published: August 2013

It’s important to improve the speed of security analysis of 96 period generation scheduling cases. Based on the characteristics of 96 period cases’ security analysis, four technical proposals were presented. They were following as fast scanning and analysis technology based on DC power flow screening, multiple thread parallel computing adapted to a multiple contingency case, multiple process parallel computing technology adapted to multiple period cases. Detailed test examples showed that the proposed methods could contribute much to fast security analysis of 96 period cases’ day-ahead dispatching schedule.
Study of the Emergency DC Power Support Strategy Based on the Principles of the Generalized Dynamics
Authors: Liu Jian Tao , Li Chen Long , Wang Ke
Published: August 2013

Emergency HVDC power support (EDCPS) can be used for improving the transient stability of AC/DC power systems, but the effect is directly determined by the quantity, the starting time, the speed and other factors of the power support. In this article, the dynamic characteristics of AC/DC power systems after a fault are analyzed, generalized dynamical models of the AC/DC power system are established, the relationship between the duration and the quantity of the EDCPS and the dynamic characteristics of the system are established based on the impulse theorem, then the EDCPS strategy besed on the principles of the generalized dynamics is proposed. At last, it is verified by examples of simulation that the strategy can effectively improve the stability of the AC/DC power systems after a fault.
The Application of Monte Carlo Simulation in Present Earning Value Method — Case Study of a Medium Hydropower Station
Authors: Zhang Ai Lan , Wang Song Jiang
Published: August 2013

Processing the parameters overly simplistic will leave space for overestimating or underestimating artificially when we assess the assets of medium and small hydropower stations using present earning value method. And absolute assumptions often affect the adequacy of the assessment results, also the persuasive and credibility. Monte Carlo simulation can determine the wave of parameters in present earning value method, so as to improve the persuasion and credibility of assessment results and reduce the personnel control.
Design of Voltage Reactive Optimizing Closed-Loop Control System in Local Power Grid
Authors: Wu Yin Feng , Wu Cui Qin , Liang Ling
Published: August 2013

By means of computer and network communication techniques, this system analyzes and calculates the real-time data, which is collected by telemetry and telecommand at every node in the whole grid via SCADA system. On the premise of ensuring the safe operation of the power grid and equipments, under the constraint condition of qualified voltage at every node and power factor of province gate way, and in accordance with power flow calculation, improved genetic algorithm and fuzzy expert system, this system is able to carry out online voltage reactive optimizing closed-loop control from the angle of the whole power grid. Thus it makes the investment of reactive-load compensation equipments and the adjustment of main transformers tap-changer more reasonable. Therefore, the system achieves the goal of local balance in reactive power stratification.
The Coordinated Control Strategies of Voltage Stability Based on Expert Rules
Authors: Zhang Fei , Guo Chun Lin , Jiang Ling Yun , Yang Lin , Zhang Jian
Published: August 2013

According to the process characteristics and control methods of different voltage stability problems, the paper researches control rules and strategies of the voltage stability, then sets up controllers of FACTS devices on a simulation platform, and puts forward the coordinated control strategies of voltage stability problems based on expert rules. The simulation studies have shown that control effects of multiple FACTS devices are significantly better than a single device, and the coordinated control methods based on the expert rules is more conducive to improving voltage stability.
An Optimal Evaluation Model for Grid Short-Circuit Current Limitation Measures
Authors: Chen Jing Hao , Liu Wen Ying , Zheng Wei , Liang Chen
Published: August 2013

A model for optimally evaluating grid short-circuit current limitation measures is proposed. Based on the fuzzy comprehensive evaluation model, a comprehensive evaluation system is introduced to consider the limiting effect and economy of the limiting measures configure program, also the program's impact on system security is involved. A judgment matrix is constructed to determine the weights of different system layers. With fuzzy behavior indices and membership function being led into, the evaluation of configuration program is given. Taking Gansu power grid for example, the feasibility and practicality of the proposed model are verified by simulation results.
Analysis of Wavelet Transform for Interharmonic Measurement
Authors: Zhang Da Hai , He Jian , Tian Zhi Guang , Li Biao
Published: August 2013

Fast and accurate measurement of interharmonic is a difficult problem. Fourier transform is widely used but it is not suitable for real-time application. Wavelet transform has better real-time performance, but its accuracy needs to be improved, so the paper studies the performance of wavelet transform for interharmonic measurement. By software simulation, it evaluates the impact of interharmonic frequency, sampling window and sampling frequency on the accuracy of interharmonic frequency measurement. Results show that wavelet method doesn’t require long sampling window or high sampling frequency, which makes it easy to be applied, and it can provide better measurement accuracy for high frequency interharmonics than low frequency interharmonics.
Energy Information Model for Power Systems Monitoring
Authors: Khalyasmaa Alexandra I. , Dmitriev Stepan A. , Kokin Sergey E.
Published: August 2013

This article presents an energy information model of a power supply system that is necessary for formation and functioning of the new system of technical policy in the field of distribution networks. The article deals with the key issues, methods and functions related to formation of the energy information model.
New Method Based on the Optimal Decomposition Scale for Daily Load Forecasting in Power System
Authors: Sun Jian Bo , Yi Chun Yan , Zhang Bu Han
Published: August 2013

The decomposition scale value is usually given by experience while the wavelet analysis method is used for daily load forecasting. Directed to the influence of decomposition scale, the paper constructed a level-termination function as SNR and put forward a constraint conditions according the accuracy requirement to solve out the optimal decomposition level. Then followed the load data which was decomposed into high and low frequency component, built up different models for different level series and sum up the forecasting result. The accuracy assessment index shows the effectiveness of the whole method and prediction thought.
Real-Time Dispatching Operation Risk Assessment Based on Fault Tree Theory
Authors: Wang En , Wei Wei , Wang Bing Dong , Liu Zhe
Published: August 2013

Reasonable dispatching strategies are important to guarantee secure and reliable operation of power system. Now the operators use real-time data and their experience to dispatch the system, but the huge data system brings much inconvenience to operators. In this paper, the risk theory is introduced into dispatching operation quantitative assessment, and a real-time dispatching operation risk analysis method is proposed. Fault tree is used to simulate dispatching operation process and comprehensively analyze the system risk in both under-successful and failure state of the operation. Risk indices are given to quantitatively reflect the risk level of each operation step based on local information, such as voltage out-of-limit risk, line overload risk, load curtailment risk, so that the operators can clearly recognize the risk and risk sources in each operation step and take corresponding pre-control measures. Finally, the effectiveness and practicability of proposed method is validated by an IEEE RTS test system.
Using Phase Shifter and OLTC to Improve Reliability during Load Transferring and System Protection
Authors: Wu Chi Jui , Huang Hsien Shun , Too Je Hsiung
Published: August 2013

When the system requires reconfiguring or repairing, the load on one of distribution feeder needs to be transferred to another feeder without interrupting. However, there are several conditions which affects the load transfer on distribution feeder, including substation types, feeder loads, and primary side voltage of transformer. Those conditions will result in abnormal high current on load transferring, and the high current will lead to the operation of overcurrent relay. This paper uses ASPEN and Matlab/Simulink to simulate the load transfer of distribution feeder, and investigate the factor that will affect protection relay. An OLTC and a phase shifter is used to improve the high current during load transfer. It will avoid the action of protection relay, and improve reliability in power supply.
Analysis and Solution of Hydrogen-Cooled Generator Hydrogen Purity Decline
Authors: Xu Yan Li , Xie Hui , Li Hai Rong , Wu Wen Long
Published: August 2013

In generators operation,the hydrogen purity is an important monitoring indictor. The change of thepurity affects unit safety operation directly. Hydrogen purity of one #10 generator unit dropquickly. Determining how to find the mainfactors is the main objective. Primarily, it was analyzed that the main reason of hydrogenpurity decrease was the air enter the sealingoil system. Though analyzing DCS history curve,as well as temperature detection test, channeling oil test, and checking thesystem pressure, finally there were two reasons, one isfill oil valve leakage fault, the two is the oil pressure difference of hydrogen side and airside in balance valve aretoo large, causing the oil channeling from air side to hydrogen side.
Research on a Novel Hybrid Adjustable Reactor
Authors: Song Meng , Dong Hong Da , Wang Da Da , Cao Kun Nan , Ren Li , Shen Shi Feng
Published: August 2013

With the development of high voltage long distance transmission and expansion of the grid, continuous reactive power compensation devices become more and more important. This paper aims to analyze a novel hybrid adjustable reactor. Based on analysis of structure and theory, simulation model and prototype are done to verify the characteristics of this reactor. Results of simulation and test confirm that the variation range of reactive power capacity is 3.5%~84.0%, and work voltage and current are approximately sinusoidal, the harmonic content is quite little. In a word, this novel hybrid adjustable reactor will play an important role in reactive power compensation.
Research on the Controlling Factors and Grate Prediction of the Output of Pulverized Coal in Hancheng Block, Eastern Ordos Gas Field
Authors: Xiong Xian Yue , Cao Dai Yong , Jie Ming Xun , Bai Yong , Zhu Xue Shen , Che Yan Qian , Zhang Ao Xiang
Published: August 2013

According to the 2012s workover treatment statistic in the Hancheng block, the eastern Ordos gas field, the workover caused by pulverized coal accounts for 41.8% of the total, which has seriously affected the continuous and stable drainage. This is one of the main factors which constraint coalbed methane production yield. In this paper, geological factors including the composition of coal petrography, the mechanical strength of coal petrography and coalbody structure destruction and engineering factors including drilling, fracturing and drainage were analyzed to study on the controlling factors on the output of pulverized coal. We conclude that the determinant on output of pulverized coal is the nature of coal seam, however engineering factors cause the output of pulverized coal directly. The root-mean-square amplitude attribute analysis was first used to display the mechanical strength of coal seam. Based on the result, we made the prediction about the possibility of the output of pulverized coal and divided the studying area into four grades. The research on the controlling factors and the prediction of the output of pulverized coal could provide the basis for the prevention and comprehensive treatment of pulverized coal.
VO2 Thin Films Deposited on ZnO Buffer Layer
Authors: Ma Jian Wei , Song Ya Rui , Xu Gang , Miao Lei
Published: August 2013

Vanadium oxide thin films have been deposited on glass and ZnO-coated glass substrates by reactive RF-magnetron sputtering deposition at different substrate temperature. The introduction of ZnO buffer layer could increase the transmittance. The buffer layer ZnO could lead to the increase of the crystallinity quality of VO2 films and substrate temperature could be decreased to 100°C for the obtaining of polycrystalline VO2 structure. The structure of VO2/ZnO/glass is considered to be potentially applicable to ‘‘smart windows’’ of high total energy efficiency in architectures or automobiles. .
Smart Detection Technology of Serial Arc-Fault on Low Voltage Power Lines
Authors: Wu Chi Jui , Hung Chen Hsuan , Liu Yu Wei
Published: August 2013

It is important to use electric power safely. Electric arcing faults on the low voltage power lines must be detected and power sources have to be shut down before fire hazards. In this paper, it suppose a method to analyze and detect arc fault characteristics. The current waveforms are different in arc fault and normal operation conditions. The discrete wavelet transform is used to obtain the spectrum characteristics of experiment data and the spectrum energy statistics can reflect the characteristics. Additionally, the values of spectrum energy are input of the back-propagation neural networks (BPNN), which can identify the arc fault efficiently. The test results have demonstrated that the proposed method is effective.
Research on the Simulation of the Roof Fracture about the Gob-Side Entry Retaining
Authors: Shi Jian Jun , Wu Run Hua , Yong Tao , Guo Jing Zhong
Published: August 2013

The geological conditions of haulage roadway of the working face 1528 in GeQuan Coal Mine, which belongs to the JiZhong Energy Group CO., Ltd., and the research findings of Key Stratum Theory was taken into consideration, based on which established a mechanical model could reflect the basic features of rock stratum and made a profound investigation on the form and conditions of the fractures on main roofs. A systematic study on the stress, deformation, and damage characters of fractures on main roofs beyond a retained entry has been made by the laboratory test. The experiment shows that the deeper the fracture is in the rib, the greater the differences between dimension of compression and deformation will likely be, and the greater the influences on the stability of surrounding rock will it has. At the same time, smaller is the overhanging beam in mined-out area, more beneficial to roadway maintenance. On a certain deformation of main roof, it creates subsidence that is great difference in different position of a roadway. The subsidence near those mined-out areas is much more than those near the ribs. The application of a strong and effective measure could help cut the roof out and assure its stability.
Parameters Setting Impact Analysis of Composite Cockpit Finite Element Analysis Based on Properties of Composite Materials
Authors: Gao Hai Peng , Liu Meng , Wang Jun
Published: August 2013

At present, mechanics properties of composite at home and abroad only include data of the single-layer board. On the basis of researching literature of composite finite element analysis, approaches of setting composite three-dimensional parameters based on the parameters of single-layer material are summarized. By three-dimensional finite element analysis on composite whole cockpit, the impact of uncertain parameters on cockpit analysis results is studied. Adopting maximum stress criteria, maximum strain criteria and Tsai-Wu criteria to evaluate the initial failure of composite whole cockpit, the impact of material uncertain parameters on initial breaking strength prediction of cockpit is studied. The study can provide reference for three-dimensional finite element analysis of composite whole cockpit.
The Dangerous Rock Mass Deformation Analysis with Application of Kalman Filter Method Based on Material Properties and AR Model
Authors: Lu Fu Min , Jiang Ting Yao
Published: August 2013

Considering the material property of the rock to the dangerous rock mass,the paper Looks the model parameter of AR( 1) model as the status vector, and uses Kalman filter method to analysis the deformation of the dangerous rock mass. The result shows that the method can improve the accuracy of fitting and forecasting of the model.
Study on Mechanical Automation with Noise Characteristic and Control of Blower Room
Authors: Liu Huan , Cui Han
Published: August 2013

The noise of blower room severity exceeds national standards,which affects normal performance of the new pharmaceutical factory,so it is necessary us to control noise. Based on the measured dates of blowers room, it carries out a noise source analysis and a discus of its noise characteristic in this article, then a controlling approach has found from absorbing noise, excluding noise to blockade sound transmission. When the controlling approach could not meet expect, a supplement program will be designed that vibration isolators will be installed under the basement of electric engine and blower, flexible metal tubes will be installed to isolate vibration spread path. After a set utility controlling approach is implemented, the consequence shows that program not only gains good effects but also caters to more advanced criterion of manufacturers demand.
Study on Mechanical Automation with Design of Mechanism Transmission System for Automobile Transmission Test Platform
Authors: Li Hong , Bo Hui Feng , Gu Jian Sheng
Published: August 2013

In this paper, the mechanical automation system of automobile transmission test platform were designed, it has been used to test the performance of the transmission after the automobile transmission is assembled. The working condition of the analogue automobile is achieved by the mechanical automation test platform.