bluuebunny/crossref_metadata_2025 huggingface dataset:
The Study of Wake and Array of Double Wind Turbine
Authors: Yang Rui , Xia Wei Wei , Li Jin Long
Published: October 2013

For the effective use of wind resources, and in order to decrease the wake effect on the performance of wind turbine, a numerical simulation has carried out to the aerodynamic interaction between two rotors coaxial arrangement. At last the numerical simulation results are verified by experiment. The results show that downstream turbine makes the upstream diverging wake to be converged when coaxial arrangement, and the output of downstream turbine is affected by upstream wake when the distance is less than 5D.The wake field become more diffused after pass the downstream turbine, the area of diverging wake become larger than the wake of upstream turbine mainly due to the increase of turbulence intensity. The greater fatigue load will impact on the downstream turbine. At last the simulation results are in well agreement with the experimental results.
The Present Situation for Wind Power Generation Development with its Countermeasures and Suggestions in China
Authors: Zhang Xi Rong , Li Qiu Yue
Published: October 2013

The wind power generation has developed rapidly, but it brings a serious of problems. This paper analyzed the development situation of the waste of wind resource, declining using hours and profit. In addition, this paper analyzed the problems and the supporting policy, with put forward to some countermeasures and suggestions of the wind power generation. It is important for China to develop the wind power generation.
Characterization of Vortex Generators Induced Flow around Wind Turbine Airfoil
Authors: Dai Li Ping , Zhang Hui , Jiao Jian Dong , Li Xin Kai , Kang Shun
Published: October 2013

Vortex generators (VGs) are an effective way to control flow separation in wind turbine. To understand the mechanism of VGs controlling flow separation, the flow field around airfoil Du97W300 with VGs was simulated and analyzed with CFD tools, and this numerical method is validated through the comparison between the numerical results and the experimental results. Furthermore, the flow fields around airfoil equipped with four different types of VGs are calculated and analyzed. The results show that the helical vortex induced by counter-rotating VGs develop approximately along streamwise direction; these types of VGs can cause a delay in stall and enhance the maximum airfoil lift coefficient. However the helical induced vortex actuated by the co-rotating VGs develop nearly along vortex generator direction and cannot cause a delay in stall effectively. In the counter-rotating VGs, the Q integration (the character parameter of induced vortex) of rectangular is twice of the triangle, and the Q integration of the forward triangle is almost equal to the backward triangle VGs.
Short-Term Prediction of Wind Power Output Based on Markov Chain
Authors: Li De Xin , Lv Xiang Yu , Song Zhi Hui
Published: October 2013

Wind power short-term predicting technology has a great significance in process of wind power decision-making. Recent years, the technology had been studied extensively in industry. Markov chain model has strong adaptability, forecast accuracy higher and other else advantages, which is suitable for wind power short-term prediction. This paper have set up one step Markov prediction model and based on which predicting short-term wind power output, and taken the historical power data of an actual wind farm in Jilin Province as an example to simulate and analyze. The paper also have proposed and used RMSE, MXPE, MAPE error analysis indicators to analyze simulation results of different status spaces. The results showed that when the status space is 60 the prediction accuracy of the method is best.
Efficiency Evaluation of Investment about China's Wind Farms Based on DEA Model
Authors: Zhou Hui Xia , Lv Xiao Jun
Published: October 2013

Wind power industry has been attracting the attention of various countries from the very beginning because of the energy shortage in recent years and Chinese wind power industry has made a rapid progress in the past five years. However, a further study is required to evaluate investment efficiency of wind power industry under the current investment pattern. By sorting out the input and output data of Chinese wind farms from 2005-2010 and constructing and measuring DEA input and output model, this paper finds that efficiency of government-led investment pattern is not high and also analyzes the reasons. Finally, the paper points out enterprises-led investment pattern will create a healthy and sustainable development for wind power industry.
Analysis of Low Voltage Ride-Through Capability for Variable Speed Wind Turbines Using Experimental and Measured Data
Authors: Lv Xiang Yu , Gao Bo , Cai Guo Wei , Li De Xin
Published: October 2013

With an increasing amount of wind energy installed, the behavior of wind turbines during grid disturbances becomes more and more important. This paper introduces the basic structures of doubly-fed wind turbines and direct-drive permanent magnet synchronous wind turbines and analyses the capability of low voltage ride through (LVRT) of the wind turbines. Finally this paper elaborates the principle and the procedures of the LVRT tests. The results of the tests show that: Doubly-fed wind turbines and direct-drive permanent magnet synchronous wind turbines are equipped with LVRT capability. The turbines are able to operate normally without disconnection and provide reactive power to support grid restoration during the dip. The direct-drive permanent magnet synchronous wind turbines are superior to the doubly-fed wind turbines on LVRT since a full-power converter is used.
Non-Linear Control System for Wind Power Plant with DFIG
Authors: Mazalov Andrey A.
Published: October 2013

Nowadays actual scientific problem of renewable energy is the problem of developing control systems, that ensure the generation of stable voltage in a changing environment. This paper presents a structure and methods of synthesis of control system development, which allow to decide the indicated problem. An electric subsystem of wind power plant is a well-known structure with well-known advantages, consisting mainly of double-fed induction generator (DFIG) and power converter in the circuit of rotor. Operation of the control system based on the original nonlinear mathematical model of DFIG in rotational "dq" coordinates, taking into account the nonlinear external and internal DFIG disturbances, such as inductances of coil winding, changes of coil winding resistances from temperature, etc. The study received adaptive control algorithms of the wind turbine output voltage parameters.
Numerical Simulation on the Dynamic Stall of the Horizontal-Axis Wind Turbine
Authors: Guo Da Fei , Xu Jian Xiang , Yuan Ju
Published: October 2013

With the variation of the unsteady incoming flow and impeller rotation, when attack angles of the incoming flow is bigger than the critical angle of attack, there are unsteady separation and dynamic stall on the pressure surface of the impeller. Dynamic stalls are of common occurrence during wind turbines operation. And the aerodynamic characteristics and efficiency of wind turbine are largely affected by the dynamic stall.Therefore,the study of dynamic stall has a great significance over the optimization design of the wind turbine. The paper performs numerical simulation in the dynamic stalls of the 1.2MW horizontal-axis wind turbine, comparing the stalling difference between two-dimensional static and rotating condition. Besides, it also contrasts the stalling condition surface pressure coefficient along the different blade spanwise sections in rotating condition of the same attack angle. And the finding is that the attack angles in rotating condition is bigger than that in the two-dimensional static condition; the surface pressure coefficient is almost equivalent in static and rotating condition when attack angle is smaller than stalling angle; the peak of negative pressure at the leading edge of blade in rotating condition is far bigger than the peak of negative pressure in static condition when attack angle is smaller than static stalling angle. Airflow stall delay occurs when near the blade root. Stall delay phenomenon gradually weakened along the direction of blade radius.
Study on the Large-Scale Water/Electricity Cogeneration System in Nuclear Power Plants
Authors: Li Jin , Li Chu Fu , Zhang Yan Xia , Yue Hui Guo
Published: October 2013

Water/electricity cogeneration system in nuclear power plants and its peaking operation modes are analyzed in this work. The large-scale water/electricity cogeneration system can use the valley nuclear power during nighttime for seawater desalination, which can improve the peaking capacity, decrease desalination water cost and alleviate the water shortage in coastal cities. The peaking operation mode results show that the reverse osmosis desalination system runs better with variable load mode "12-1-10-1" (day 50% - night 100%) under the full load operation of nuclear reactor. In this mode, the peaking capacity of the water/electricity cogeneration system is 33%, the desalination water cost is 3.49 Yuan/m3 and the peaking cost is 65 Yuan/MWh. Development of the large-scale water/electricity cogeneration system in nuclear power plants has multiple benefits in China.
Research Methods of Severe Accident Source Term for Nuclear Power Plant
Authors: Chen Hai Ying , Wang Shao Wei , Chen Yan , Lan Bing , Zhang Chun Ming
Published: October 2013

Source term is an important input parameter for evaluation of the radiological consequences in the severe accident and can affect the level of emergency response. The research methods of severe accident source term mainly include numerical simulation and experiments inside and outside reactor. The simulation and experiment research progress of the severe accident source term and the results were discussed, mainly including the migration and release behavior of radioactive nuclides in severe accidents, their existing forms and distribution, the effect of engineering measures on the radioactive source term, the sensitivity analysis of parameters, model verification, etc. Finally, the problems needed to be solved in the severe accident source term research currently were proposed, which could be used to provide reference for the further research.
Fault Diagnosis of Grounding Grid Based on Self-Adaptive Particle Swarm Optimization
Authors: Lan Wen Hao , Zheng Yi Hui , Li Li Xue , Wang Xin , Yao Gang , Zhang Yang
Published: October 2013

To make effective fault diagnosis of grounding grid , a new method using Self-Adaptive Particle Swarm Optimization (SAPSO) is proposed. Firstly, the grounding grid can be handled as a resistive network to establish fault diagnosis equations. Then the objective function based on minimum energy principle is added to lower the ill-condition of diagnostic equation. Next, according to optimization techniques, a new method of SAPSO is proposed to solve the corrosion diagnosis equations. The method takes advantage of the high global searching ability of SAPSO to obtain the optimal solution to the diagnosis model. By means of the analysis of the simulation, the correctness and reliability of the method have been verified.
Fault Location Method and Hardware Monitoring System of Parallel Compensating Capacitors
Authors: Li Yan , Yang Lei , Zhu Li Wei , Zhao Tao , Liu Yun Peng , Gao Li
Published: October 2013

At present, the operational parallel compensating capacitors can only through the protection action for the information, so we cant location the fault capacitor. In order to obtain every parallel capacitor running status information and according to internal structure and the operation mode of film capacitor, this paper propose a method of locating a capacitor, and based on this method constructs a set of hardware monitoring system. This method can eliminate the affection caused by the environment and measurement error of sensor accuracy effectively and the hardware monitoring system can solve the insulation problem, which high-potential power supply and wireless collection and transmission technology bring.
The Type D Double-Ended Traveling-Wave Distance Protection for HVDC Based on Wavelet Transform
Authors: Ye Ning , Ren Yan , Fu Dai Yin
Published: October 2013

This paper describes the modern Type D double-ended location principles and the wavelet modulus maxima theory and presents a principle and a scheme which bases on wavelet transform of the Type D double-ended traveling-wave distance protection for HVDC traveling line. Then set up a monopolar HVDC system and simulate it by PSCAD/EMTDC and Matlab. Simulation shows that this protection principle and scheme is right and feasible.
Experimental Study on Critical Process Parameters Regarding Tension Stringing Construction of 1250mm2 Large-Section Conductor
Authors: Hu Chun Hua , Xia Yong Jun , Li Junz Hang
Published: October 2013

Critical construction process parameters and necessity of experimental study concerning tension stringing of large-section conductor are elaborated in this paper and in addition, test details related to critical process parameters of tension stringing construction is researched by citing the example of 1250mm2large-section conductor, according to which test plan is worked out and test rack is designed.
Research on Influence Factor of Primary Frequency Regulation Performance for Thermal Power Plant
Authors: Liang Zheng Yu , Li Shan Shan
Published: October 2013

As a basic auxiliary service, primary frequency regulation (PFR) is provided with significant effect in secure and stable operation for grids. Thermal power plants undertake important task in PFR by virtue of it is main type in grid-connected power plants. However, some problems such as slow response, inadequate load variable quantity, or even reverse regulating effect exist in actual PFR process. In PFR relative control logic, PFR command, load variable quantity command and main steam pressures influence must be taken into consideration. Regulating valves flow characteristics and adjustment of overlap degree can result in imbalance of load regulating under different working point. Frequency data utilized by grid dispatching center and power plant are inconsistent so that PFR evaluation may be affected. On the premise of safe operation in power plant, energy storage can improve units load in a fast time. A series of optimization measurements are put forward on the basis of the above four influence factors. In accordance with respective influence characteristics, these measurements possess a certain reference significance to improve performance index of PFR.
Application of Wavelet De-Noising in Non-Stationary Signal Analysis Based on the Parameter Optimization of Improved Threshold Function
Authors: Nie Hai Zhao , Liu Hui , Shi Lei
Published: October 2013

Using wavelet analysis for non-stationary signal de-noising of electro-mechanical system is considered to be the best approach, and wavelet threshold de-noising method is the most simple method that needs the minimum amount of calculation. But this method in selecting threshold functions needs to be improved. Based on different domestic and foreign methods of improving threshold function, propose an improved bivariate threshold function. According to the simulation of non-stationary signal de-noising, the results show that the optimal de-noising results of different signals exist by taking different parameters. Compared with all the de-noising effects, application of the bivariate threshold function considering signal-to-noise ratio and mean square error is superior to the traditional soft and hard threshold functions. At the same time, it can significantly improve the filtering precision, and reserve the main signal details while effectively removing the noise well.
Simulation Study of High-Frequency Circulating Bearing Currents of 300kW Induction Motor
Authors: Zhang Hai Jiao , Liu Hui Juan , Li Rui Fang , Niu Shuang Xia
Published: October 2013

Bearing electrical erosion caused by circulating bearing current exists in the high-power induction motor, which affects the safety of drive system. This paper presents a theoretical analysis of the generation of circulating bearing current based on electromagnetic field theory. 2D finite element analysis is adopted to calculate the parasitic capacitance and loop current method based electrical network theory is used to analysis the distribution of the common mode current. A new and reasonable circulating current equivalent circuit is built up. A 300kW induction motor fed by PWM inverter is simulated with MATLAB /SIMULINK software and the circulating bearing current of the motor is calculated.
Analysis of a Tubular Linear Permanent Magnet Motor for Reciprocating Compressor Applications
Authors: Abdalla Izzeldin Idris , Ibrahim Taib , Mohd Nor Nursyarizal
Published: October 2013

This paper describes a design optimization to achieve optimal performance of a two novel single-phase short-stroke tubular linear permanent magnet motors (TLPMMs) with rectangular and trapezoidal permanent magnets (PMs) structures. The motors equipped with a quasi-Halbach magnetized moving-magnet armature and slotted stator with a single-slot carrying a single coil. The motors have been developed for reciprocating compressor applications such as household refrigerators. It is observed that the TLPMM efficiency can be optimized with respect to the leading design parameters (dimensional ratios). Furthermore, the influence of mover back iron is investigated and the loss of the motor is computed. Finite element analysis (FEA) is employed for the optimization, and the optimal values of the ratio of the axial length of the radially magnetized magnets to the pole pitch as well as the ratio of the PMs outer radius-to-stator outer radius (split ratio), are identified.
Functionally Complete Elemental Basis of Mathematical Schemes of Electrical Circuits
Authors: Viktorovich Pivnev Vitaliy , Nikolaevich Basan Sergey
Published: October 2013

The paper gives the definition of the mathematical electrical circuit scheme, the extended element basis, the minimum and full functional element basis. The theorem about functionality of the full minimum element basis for the synthesis of mathematical diagrams of electrical circuits, which consists of: ideal conductor, ideal switch, one independent and one dependent source of electrical energy, capacitance or inductance, was convinced. There are a few variants of functionally complete minimal element bases.
Effect of Different Heat Rejection Scenarios on Cooling Tower Plume Dispersion
Authors: Guo Rui Ping , Yang Chun Lin , Lan Bing , Zhang Chun Ming
Published: October 2013

This impact of heat rejection on cooling tower plume dispersion was studied in this paper by applied SACTI (Seasonal Annual Cooling Tower Impact) model. In order to analyze the impact of heat rejection (HR), we set five scenarios including observed, HR decrease 5% (HR-5) and 10% (HR-10), and increase 5% (HR+5) and 10% (HR+10). Results showed that plume length frequency, plume height frequency and plume radius frequency will present different variation trend when heat rejection increase and decrease scenarios. On the whole, the plume character parameter will decrease as heat rejection decrease, but will increase as heat rejection increasing.
The Dipole Antenna with Photonic Crystal Structure Used for Mobile Communication
Authors: Lin Bin , Lin Ting , Ge Yang , Wang Rong Rong , Guo Yong Ping , Lin Zhi Da , Wang Zheng Zeng , Su Cheng Xiang
Published: October 2013

The antenna design and its manufacturing technology is one of the gordian technique in mobile communication system, the performance of antenna influences the performance of the mobile communication system directly. To mobile communication system, the study of antenna has important significance. The development of mobile communication system brings a new request to the antennas design. This paper start from dipole antenna and the structural theory of photonic crystal, bat around the superiority of the two, and make a combination, design a dipole antenna with photonic crystal structure which can work in 2GHz frequency range, small size, return loss in low and bandwidth is suitable for CDMA2000 mobile communication system, and we simulate and test the performance of this antenna, discuss how the parametric variation will influence the performance of antenna.
Assessment and Prediction of Joint Toxicity of Aniline Derivatives
Authors: Ge Hui Lin , Liu Shu Shen , Yuan Hong Qiu , Yin Gui Hao , Xie Yi , Mo Ling Yun
Published: October 2013

The joint toxicity of aniline, 2-methylaniline, 3-methylaniline, 4-methylaniline, 2-nitroaniline, 3-nitroaniline, 4-nitroaniline, 2-chloroaniline, 3-chloroaniline, and 4-chloroaniline on photobacterium were predicted and evaluated by using concentration addition (CA) and independent action (IA) models, and joint effect indices including toxic units, additive index, mixture toxicity index, and similarity parameter. The tested mixture presented synergism.
A New Control Strategy for the STATCOM Based on Multi-Model Neural Network PI Controller
Authors: Zhou Chen , Zheng Yi Hui , Yao Gang , Li Li Xue , Wang Xin , Liu Yan Wen
Published: October 2013

Aiming to dealing with the problems of power factor compensation and the limitations of the conventional PI controller in the Static Synchronous Compensator (STATCOM), a new control strategy based on multi-model and neural network PI controller is proposed. This control scheme applied the multi-model and neural network technology to the PI controller to meet the accuracy and speed of the power factor compensation under different impact loads. Meanwhile, the neural network technology is used to tune the PI controller parameters values according to an optimal control law, which can meet the requirements of full range working conditions and optimality. Simulation experiments show that compared to the traditional PI controller, PI controller based on multi-model and neural network is proved to be better capable of adapting to the changes of impact loads with a higher compensating precision, which makes the power factor maintained at about 1 after compensation.
Analysis on the Current Situation in Nurses Self-Cognition on Disaster Relief in Grade a Class Three Comprehensive Hospitals
Authors: Xu Min , Wang Chun Xiu , Xing Chun Mei , Zhang Shu Rong
Published: October 2013

The aim of this study was to investigate the current situation in nurses self-cognition on disaster relief in grade A class three hospitals in Jilin area. 457 Valid questionnaires of 480 objects selected with a combined group sampling and random sampling method were taken back and the withdrawing rate was 95.2%. The results showed that in grade A class three comprehensive hospitals in Jilin area, the nurses professional skills and professional technical qualities were good enough to cope with the nursing in disasters. There were statistically significant differences in the score of the knowledge on disaster relief theory and skills among different departments or different education backgrounds, suggesting that the relevant knowledge and the integrated physical, psychological and social care should be strengthened in their future training. The majority of nurses in hospitals in Jilin area showed a positive attitude to disaster relief. However, the policy makers should give appropriate preferential policies to the disaster relief work.
A New Method to Detect Voltage Sag Based on Wavelet Energy Entropy
Authors: Wang Chang Gang , Wang Lin Chuan , Liu Jia , Liu Bin
Published: October 2013

Voltage sags was a common power system disturbance, usually associated with power system faults. Nowadays, there were more and more methods to detect voltage sag, involving with RMS, peak voltage detect, FFT. Owing to their defections, they were too slow when they came to being applied to detect voltages sags. This paper presents a method based on wavelet energy entropy detection voltage sags, this method can detect the drop time quickly and sensitively. In order to verify the feasibility of the proposed method, a numerical example simulation has been done based on matlab / simulink , results show that there is a significant effect.
Research of Fault Type of Transformer Winding Based on Frequency Response Analysis
Authors: Zhang Xin , Wang Xin , Zheng Yi Hui , Li Li Xue , Zhou Li Dan , Zhao Chang Shun
Published: October 2013

In this paper, a novel method based on FRA is proposed to detect both the fault and the deformation type. Firstly, a model of the transformer winding is established based on the electrical properties of winding. Secondly, as the winding frequency response curve change in accordance with the change of the parameters of winding model, the rule of the variation of winding frequency response curve is drawn out based on the model above. Thirdly, the effect of various types of winding deformation on the changes of the parameters of transformer winding model is summarized. Finally, an experimental example of the diagnosis of deformation type is conducted on a testing transformer based on the analysis of frequency response curves, hence the validation of the correctness of the simulation results.
FEM Simulation of PD Acoustic Signal Propagation in Transformers
Authors: Dong Yue , Qian Yong , Ye Hai Feng , Jiang Xiu Chen
Published: October 2013

In order to study propagation process of partial discharge ultrasonic signal in power transformer, the finite element method is used for simulation modeling and calculation. Ultrasonic waves can be activated by partial discharges (PD) in power transformers. The ultrasonic method is used for evaluating the insulation condition of power transformers by analyzing the partial discharge signals information which is detected by AE sensors. Compared with other diagnostic methods the AE method causes relatively low disturbance, and measuring apparatus is simple and easy to use. This technique is noninvasive and immune to electromagnetic noise. Simulate partial discharge sources of different positions respectively. Achieved results indicate that the space and time distributions of the acoustic pressure depend on the induction position. Furthermore, a greater pressure gradient is observed in domains with higher speed of sound while the signal amplitude decays when it moves away from the PD source.
Algorithm and Realization of Arrester in Cable Line in Online-Monitoring System
Authors: Zhang Xi Lin , Wang Zhen Hao , Han Xiao Juan , Pang Dan , Wang Chao Bin
Published: October 2013

Algorithm and realization of the arrester in cable line in online-monitoring system based on the resistive current detection using phase search is discussed in this paper. The effectiveness of this method is manifested by the actual experience in the engineering construction.
Impact of Wind Speed Correlation on Transient Stability of Power System
Authors: Zhang Long , Huang Jia Dong , Xu Xian Xin , Pan Xiong
Published: October 2013

Wind speeds of different wind turbines in a big wind farm always have correlations because of their close geographical location. This paper builds wind speed model by t-copula function and uses rank correlation matrix to measure the correlation of wind speeds. The case study of IEEE-39 bus system and Yunnan Power Grid shows that wind speed correlation has certain effect on the transient stability of power system.Taking wind speed correlation into consideration makes the analysis of systems transient stability more close to reality.
Multi-Source Fusion Power Quality Monitoring and Analysis Application System
Authors: Wang Guo You , Shi Yu , Zhang He , Su Biao Long , Zhang Xiao Qing
Published: October 2013

There is a restriction on the development of power quality monitoring software for lacking of corresponding technical specification and uniform systematic planning. In this thesis, the concept of supporting platform of power quality monitoring and analysis system is posed and the supporting platform provides data service, report work, authority management, alarm service, authority management, communication service and other public services; abiding by the advocacy of IEC 61970 Standard, the system applies CORBA component technology inside and outside the system and realizes the “plug and play” of public services and applications. Through the standardized public communication service module, the data interaction with other power quality monitoring software, PMS system, DMS/EMS system and other third-party systems is completed and the multi-angle and deep power quality analysis are conducted based on multi-source information fusion technology and the power quality analysis and evaluation, harmonic source location, power quality warning, management decision support and other intelligent analysis application are realized.
Nonlinear Dynamic Power System Model Reduction Analysis Using Balanced Empirical Gramian
Authors: Zhao Hong Shan , Xue Ning , Shi Ning
Published: October 2013

This paper presents an empirical Gramian balanced reduction method which efficiently solves nonlinear power system model reduction problems. This method projects the nonlinear power system dynamic model to a lower dimension subspace and the reduced model can retain the original nonlinear system input and output dynamic behaviors. A four-generator nonlinear power system, combining different factors which form empirical controllable and observable Gramian matrices, is used to analyze how external excitations and outputs affect balanced empirical Gramian reduction. The case verifies the feasibility and effectiveness of balanced empirical Gramian reduction method.
Frequency Response Model of Regional Power Grid Based on Parameter Identification on Trip Process of Transmission Line
Authors: Tao Hao , Tang Yao H¨ua , Zhou Xu Zhan , Wang Hong Wei
Published: October 2013

Many large power grid accidents show that the tripped transmission line has great impact on system stability. The primary frequency regulation effects of generation units play key roles during a trip procedure. In this paper, a frequency stability dynamic mathematic model of regional power grid was built based on records of a practical trip accident of transmission line between regional grids. Key parameters of the model were identified. The identified parameters are within their reasonable regions. The simulation results show that the modeling method based on parameter identification can be used for modeling of transmission line trip accident procedure and relative frequency stability analyses on power grids.
Calculation and Analysis of the Effect with Electric Vehicle Connected to the Distributed System
Authors: Sun Ying Ying
Published: October 2013

With the development of electric vehicles technology, especially the development of battery technology and strongly supported by some developed countries in terms of policy, electric vehicle has undergone a rapid expansion in recent years. A lot of electric vehicles are popularized and applied, which will have an impact on power system especially the distribution system. Therefore it is necessary to study the demand characteristics of electric charging and the treatment method and model of access to the network. With this understanding, this article studies the power output model of electric vehicle and analyzes the impact to the distribution network load, the network loss and voltage with different electric vehicles capacity.
Matching of Generator Low Excitation Limit Setting and Loss-of-Excitation Protection between Different Coordinates
Authors: Zhao Hua , Wu Chun Hong
Published: October 2013

In generator setting calculation, the loss-of-excitation protection impedance round is in the R-X plane, while the low excitation limit setting is in the P-Q plane. In this paper, the R-X plane and the P-Q plane coordinate conversion on the matching of generator low excitation limit setting and loss-of-excitation protection are proposed. Using a power plant example, the method has been proved convenient.
The Application of Dispatch Operation Ticket System Based on Intelligent Anti-Misoperation Method
Authors: Sun Jian Wei , Tang Sheng Wei , Liu Fei
Published: October 2013

As an effective means to reduce or eliminate power accidents, dispatch operation ticket system has gained more and more concerns and application. The existing dispatch operation ticket system is most based on logic rules, and strongly relying on network topology, which is hard to be extended. In view of the above mentioned problem, a new power grid dispatch operation ticket system based on intelligent anti-misoperation method is designed in this paper. First, the overall architecture of dispatch operation ticket system is introduced. Then, the regulations of anti-misoperation are analyzed in detail. And the typical anti-misoperation procedure is provided. Finally, the application and realization of the system is clarified from both hardware configurations and software programming.
Probabilistic Assessment of Voltage Stability of Power System with Wind Farm Based on Credibility Theory
Authors: Yang Yue , Li Guo Qing , Wang Zhen Hao
Published: October 2013

The static voltage stability of power system with wind farm is simulated by fuzzy simulation. This method is able to calculate not only the expectations and standard deviations of diagonal elements of Jacobian reduction matrix with the uncertain parameters but also the static voltage stability indicator based on the credibility theory. The method is characterized in that the impact of the assumptions of distribution function type of uncertain parameters and parametric statistics is avoided by this method. The calculated results are impacted only according to the actual changed range and the types of membership functions of uncertain parameters. Finally the calculation results based on that method are compared with the calculation results based on two-point estimation method and Monte Carlo simulation method. The results show that the superiority and accuracy based on the method is proved.
Research on Transient Stability Critical Clearing Time Calculation Based on Predictor-Corrector Cantor-Like Search
Authors: Huang Long Xiang , Zhao Feng , Qiu Wei Jiang , Miao Shi Hong
Published: October 2013

This paper proposes a new approach which applies Cantor-like search strategy to computing critical clearing time (CCT) after searching the initial search interval of fault clearing time (FCT) by advance-and-retreat predictor-corrector technology. On the basis of discussing the mathematical nature of computing CCT based on time-domain simulation, the work started with the comparison of conventional computer linear optimization search strategies, then combined Cantor-like search with transient stability analysis feature and realized CCT rapid calculation with the classical Dichotomy substituted. Simulations on New England 10-generator 39-bus system demonstrate that this new algorithm has a good advantage over efficiency and precision, as well as its engineering application prospect.
RTDS-Based Real-Time Simulation Model of Fiber Optical Current Transformer
Authors: Liu Qing , Fu Dai Yin , Sun Tian Kun , Zhang Dong
Published: October 2013

This paper set up the real-time simulation model of FOCT by means of RTDS. The equivalent model of FOCTs digital closed-loop control system was created by simplifying that systems deviation and feedback .The temperature was also introduced in that model above according to the temperature change law of the optical fiber Verdet constant and λ/4 wave plate phase delay and the mathematical model about λ/4 wave plate parameters of the light intensity received by the detector. The results show that the real-time simulation model of FOCT is reasonable, and can simulate FOCTs steady state temperature characteristic. Its transient characteristic is not bad and it can be used for testing smart substations correlative equipment.
Evaluation on Environmental Planning of Eco-Industrial Park in China
Authors: Jin Feng , Xing Li Zhi
Published: October 2013

An Eco-industrial Park (EIP) is an industrial park developed according to the theory of industrial ecology, which can significantly reduce industrial pollution and improve regional or local sustainability. On the account of the requirements on energy and material flows connection, the construction and development of EIPs are contingent for effective environmental plannings. China initiated the construction of EIPs during foundation of the previous economic and technological development or high-tech districts in 2001, by classifying EIPs into 3 categories: Integrated Eco-Industrial Park, Sector Eco-Industrial Park and Venous Industry based on Eco-Industrial Park. In each category, EIP contributes significantly to the regional and local economy as well as regional and sustainable development. The environmental planning for EIP is guided by three independent standards and by the HJT 409-2007 guides for the establishment of EIP Planning, which makes regulations on the principles, methods, contents and detailed requirements of the EIP planning. The purpose of this study is to identify the effectiveness of EIP planning in China. This article reviews the theory and practice of EIPs in China and summarizes Chinas environmental planning (EP) system. A case of EIP is presented for qualitative analysis and for the evaluation of the effectiveness of the EIP planning. The results of the evaluation on both the achievements and the processes of plannings goals, from the perspective of environmental carrying capacity (ECC), reveal the challenges of EIP planning in China. Then recommendations are provided on how to improve Chinas EP system for EIP to achieve the desired results.
Method for Illconditioned Parameter Estimation Application in Synchronous Generators
Authors: Moghadam Farshad Gholami Nejad , Taghizadegan Navid , Meraj Haghi Pour
Published: October 2013

Fault detection, isolation, and fault diagnosis for a synchronous generator is a desirable feature that could aid in better monitoring and automation of the machine behavior, and could have a significant impact in establishing an adequate maintenance schedule that ensures proper operation while taking into consideration cost and risk of having a large generator and its maintenance. This work looks in parameter estimation’s algorithm methods those can used in fault detection, isolation and diagnosis. In a broad sense, a fault is understood as any kind of anomaly or malfunction that leads to an undesired performance of the system under consideration.
Multi-Objective Optimal Planning Design Method for Stand-Alone Microgrid Systems
Authors: Qiao Lei , Guo Li , Luo Chu Ning
Published: October 2013

In this paper, a multi-objective optimal planning design model including net cost, loss of capacity and pollutant emission in a life cycle was presented for a stand-alone microgrid system with diesel generators, wind turbine generators, photovoltaic generation and lead-acid battery. In this model, the two coordinated operational strategies between diesel generators and battery, the dispatching method for diesel generators, and the reserve capacity were considered. The type and capacity of distributed generation units were selected as the optimal variables. The optimal allocation of distributed generation units and battery for an island microgrid system was carried out under the different combination objectives and control strategies by the self-developed software (Planning Design System for Microgrid, PDMG).
Impact Factor Estimation on Power Quality to Electric Power Market
Authors: Feng Wei Yuan , Dong Xue Feng , Yu Xu Dong , Wang Shuang Wen , Liu Zhong Jing
Published: October 2013

Power quality and power marketing are comprehensive concept contains multiple indexes. This paper builds the index system of the power quality promoting the power market development. And the structural equation modeling (SEM) be used to calculate the impact factor of power quality to marketing at different times and areas. This paper firstly puts power quality and marketing which are regarded as latent variables. And select the power quality index that includes the amplitude, frequency, spectrum, modulation, the notch depth and marketing index that includes market share, electricity consumption per capita, customer satisfaction rate, install electricity rate, customer loss rate as measured variables of latent variables, and establish the causal influence path graph of power quality and power marketing. According to the path graph, which reflecting causal relationships among the latent variables and the measurement equation reflecting relationship between the latent variable and significant variables. To test the significance and the rationality of the parameter and evaluate the overall performance of the structure equation model. Finally, according to the path graph and the path coefficient, we get causal influence coefficient between the power quality comprehensive index and power marketing comprehensive index.
Power Planning Model of Microgrid Based on Minimizing the LCC Cost
Authors: Zhang Hao , Tian Shao Yu , Liu Zhong Jing , Chen Fang
Published: October 2013

The development of micro-grid technology provides power system a variety of forms, flexible ways of power supply schemes, but a lot of basic micro-grid operational problems are different from the traditional large power grids, which need to be studied specifically. This paper studies the power planning problem of micro-grid, namely to meets the system operational constraints, study how to optimize the micro-power configuration of micro-grid, so that the whole micro-grid life cycle cost is the smallest.
Risk Management of Virtual Power Plant Reserve Allocation
Authors: Li Tian Ran , Luo Yun Hu , Sun Lin
Published: October 2013

Virtual Power Plant (VPP) is a new entity in power systems that manages a set of various distributed energy resources (DERs). One of the functions of VPP is to determine the allocation of reserve to solve the problem of renewable generation uncertainty. In this paper, the reserve resources of VPP are classified into non-renewable distributed generation (NRDG), energy storage device (ESD), interruptible load (IL) and reserve bought from the market (RBFM). Their complementary properties should be utilized to improve the economy of reserve allocation. An optimal coordination model for risk management of NRDG configuration of VPP reserve allocation is proposed. Simulation results are presented to validate that an optimal value of NRDG configuration should exist.
Connotation and Research Areas of Coordinated Development of Power Supply, Load and Power Grid in Sichuan
Authors: Du Xin Wei , Ren Zhi Chao , Wang Hai Yan
Published: October 2013

With the rapid growth of hydropower in Sichuan, power structure becomes a primary issue of development of power grid. In this paper, the understandings of the connotation of coordinated development are proposed that it is of importance to rely on power exchanging using power grid platform to supplement provincial power and load characteristic. Main research contents are summed up from nine areas from the aspects of inside and outside province. And some difficulties needed to pay attention are also explained.
Energy-Saving Analysis of 215MW Cogeneration Boiler Adding Low Temperature Economizer
Authors: Liu Yan Feng , Li Shi Ping , Li Xiang Hong
Published: October 2013

A 215MW cogeneration B&W670/13.7-M type high-pressure natural circulation boilers, the exhaust gas temperature is set as 143 °C, while in the actual operation, the average exhaust gas temperature is 155 °C, and when the unit is running at full capacity in summer the highest exhaust gas temperature is 169.6 °C. In order to satisfy the normal operating temperature of bag filter in summer peak load, and recover low temperature waste heat of fule gas, low temperature economizer is added to the thermal system. Therefore, low-temperature economizers are respectively added in four flues which are between the outlet of the air preheater and the entrance of the bag filter, this will achieve the purpose of reducing flue gas temperature by transferring heat between condensate and flue gas, ensuring the units safe operating and improving the overall operating performance of the boiler.
The Application and Evaluation of the Hybrid Energy Storage in the Wind Farms
Authors: Ding Ming , Xie Jia
Published: October 2013

The intermittency and volatility of wind power has brought adverse effects on the large-scale wind power integration. The hybrid energy storage system coordinated with wind farms has been set up in order to reduce the volatility of output power of wind farms strongly. The allocation plan between high-frequency and low-frequency wind power can be determined with low-pass filter method in order to determine the restraining target of different energy storage devices. According to the capacity and the state of charge of the batteries and super capacitor, the power reference values can be corrected with fuzzy adaptive control method and exceeded power deviation of the target would be allocated between the two kinds of energy storage devices. The reasonableness of the proposed models is verified by case study results.
Research on Energy-Saving Scheme Based on LED Street Lamp Management-System
Authors: Gong Yue , Han Peng
Published: October 2013

Along with the rapid development of the Internet of things, the concept of intelligent city gradually affect our life. In a large number of consumption we enjoy intelligent bring convenience and was accompanied by energy. This research is the energy-saving LED street lamps lighting the city plan. Different environment for city street lamp, street lamp pole through the parameter sensor acquisition itself, integrated, intelligent to develop energy-saving light modulation scheme. At the same time, according to city various scenarios to develop energy-saving strategies, so as to solve the problem of energy waste city street planning unreasonable, light modulation scheme is not perfect cause.
Simulation Research of Liquefied Natural Gas Cold Energy Recovering Cycles in Refrigerated Truck
Authors: Zhang Zhe , Tian Jin Jin , Guo Yong Gang , Sun Bing Bing
Published: October 2013

LNG can provide plenty of cold energy when it is used as the fuel. The cold energy can be recovered and utilized in vehicle refrigeration. The basic principles of LNG refrigerated truck and the design of cold recovery system were described. In order to research the cooling performance of LNG refrigerated truck, a simulation model was established. The effects of the glycol inlet temperature, the glycol and natural gas flow rates, wind speed and the system pressure on the cooling capacity and air outlet temperature were analyzed. The results show that ethylene glycol flow is an important factor on system performance and LNG cold energy recovery is suitable for the refrigerated truck.
Study on Droop Control Strategy with Application to Flywheel Energy Storage System
Authors: Lv You Ran , Wang Lei , Xiang Jia Yi , Yang Feng , Du Xiao Qiang
Published: October 2013

The flywheel energy storage technology is a kind of method that converts electrical energy into kinetic energy in store. The flywheel energy storage system (FESS) is usually used for renewable energy system such as wind turbine generator system (WTGS) to adjust the quality of output power. Droop control is a kind of control technology to regulate the active power and reactive power in micro-grid. In this paper, we introduced a method to combine the droop control with FESS and designed the control topology. The droop control method was applied to control the part of inverter in FESS. By controlling the output frequency and the voltage amplitude of WTGS-FESS system, we can regulate the output of the inverter as a promotion in smoother active power and reactive power.