bluuebunny/crossref_metadata_2025_split huggingface dataset:
Peak-valley time division model based on net load curve
Authors: Guo Junhong , Xue Xiaoqiang , Li Ling , Cheng Yiping , Li Yajie 
Published: April 2020

Abstract
As China has been quickly promoting its power market reform, the degree of thermal power units participating in market transaction has been gradually deepened. Aiming at different situations of load, thermal power units need to adopt bidding strategy accordingly. In power system with high proportion of renewable energy, the competition curve that thermal power units actually face is no longer total load curve. Proper division of peak-valley time intervals will guide thermal power units to adjust bidding strategy positively and effectively in the competition. A net-load-curve-based peak-valley time division model is built in this paper with the help of K-means algorithm. And then the paper contrasts and analyses the distributive characteristics of total and net load curves through a calculation example to verify the positive effect this model has on accurate bid for thermal power units.
Optimized dispatching based on wind-photovoltaic-hydropower-thermal-bundled strategy
Authors: Wang Xi , Liu Fang , Wang Yunling , Zhu Mi , Liu Ying , Lin Zhiyu , Li Huaqiang 
Published: April 2020

Abstract
The rapid development of wind power and photovoltaic is conducive to optimizing the energy structure and resolving fossil energy crisis, in response to the strategic direction of energy saving and emission reduction in China. However, the intermittence and fluctuation of wind, photovoltaic and other renewable energy sources pose greater challenges to the secure and stable operation of the power grid. Therefore, it is of theoretical significance and practical value to study the optimal dispatching of power system with wind and photovoltaic large-scale connected to grid. This work proposes an optimal scheduling strategy based on wind-photovoltaic-hydropower-thermal bundled according to the energy sources reasonable allocation proportion. The strategy gives full play to the complementary characteristics of energy, and realizes the comprehensive optimization of system peak shaving, economic cost and environmental benefit. The bundled power configuration layer defines the bundled fitness index, which takes into account the comprehensive influences of conventional unit utilization rate, load tracking degree and wind power abandonment. Based on the commercial optimization software CPLEX, the output of conventional hydropower units and the combination of thermal power units are solved. Finally, the feasibility of the model is verified by a case study.
Multi-SGI interconnected real-time HIL simulation of Yu’E MMC-HVDC project
Authors: Liu Chong , Zhu Yiying , Yang Limin , Yin Pingping 
Published: April 2020

Abstract
With the interconnection of regional grid and wide application of HVDC and FACTS in power grid, the scale of grid is increasing rapidly, and this makes the power system simulation techniques face new challenges. In this paper, based on decoupling algorithm and high speed optical fiber communication, the interconnection between multi-SGI(multiple SGI supercomputers) is proposed to implement HYPERSIM co-simulation. The HIL test of Yu’E MMC-HVDC project is implemented using the HYPERSIM co-simulation platform, the test results verify the real-time simulation capability of the proposed scheme.
Experimental and numerical investigation of combustion system improvement on 600MW bituminous coal boiler for burning lignite coal
Authors: Xu Yanhui , Guo Xin , Yu Qiang , Huang Ying , Wang Jingjie , Sun Hao , Ma Xiaochun , Guan Jingyu , Li Wei , Song Zhenyu , Jia Geng 
Published: April 2020

Abstract
A 600MW supercritical direct-current (DC) utility boiler co-firing bituminous coal with lignite, has the problems from over-large desuperheating water yield in the reheater and over-high NO
x
emission concentration. In this paper, the causes of the problems are analyzed through, the initial tests of pulverization system and combustion system, the adjustment of combustion, etc. The results show that the combustion in furnace lagged behind to some extent after co-firing the bituminous coal with the lignite and the center of the flame was elevated, which shortened the relative distance between the flame of the main burners and over fire air(OFA), enlarged the absorbed heat amount of the reheater and reduced the residence time of flame in the reduction zone prominently. The much less residence time would increase NO
x
emission. Based on the calculations of the actual operation conditions of the burners, a series of improvement measures were proposed. After performing numerical simulation and cold test verification for the improvement measures, the corresponding transformations of the power plant were carried out. The desuperheating water yield in the reheater decrease, obviously, and over-high NO
x
emission is controlled effectively.
Hydraulic turbocharger for energy recycling in the reverse osmosis seawater desalination system
Authors: Ji Yunguang , Li Xiaoxia , Li Hongtao 
Published: April 2020

Abstract
In order to reduce the energy consumption of the reverse osmosis seawater desalination process, a hydraulic turbocharger is proposed to recycle the pressure energy of the brine. A high efficiency energy recovery hydraulic turbocharger is designed based on Computational Fluid Dynamic method and installed in the reverse osmosis seawater desalination system of Dagang Power Plant in Tianjin Development Zone, China. The actual operation results show that the hydraulic turbocharger has apressure energy recovery efficiency of up to 72%, and with high working stability and low noise, which may provide areliable reference for the design and application of pressure energy recovery devices.
Precipitation forecast on the township scale using the frequency matching method
Authors: Wang Shusu , Yu Li , Zhu Shoupeng 
Published: April 2020

Abstract
Based on the daily accumulated precipitation from the European Centre for Medium-Range Weather Forecasts (ECMWF) as the forecast data, and the daily accumulated precipitation from ground meteorological stations as observations, experiments of precipitation forecast on the township scale are carried out by means of the frequency matching method. The results show that, compared with the bilinear interpolation, the frequency matching method is more effective in increasing the anomaly correlation coefficient and the equitable threat score, as well as decreasing the root-mean-square error, the false alarm rate of light rain and the missing rate of heavy rain. The frequency matching method can greatly calibrate and improve the refined precipitation forecast on the township scale.
Prediction and research on the erosion of the tubing joint in high yield gas well
Authors: Ni Hongjian , Cao Yucheng , Liu Chengwen 
Published: April 2020

Abstract
Sand production in high-yield gas-well is a common problem in oilfield. Erosion caused by sand production, often leads to pipeline failures and even endangers lives and property if serious. So, the sand production problem cannot be ignored. In this paper, computational fluid dynamics are used. I conduct numerical simulation in allusion to the process of gas flowing through pipeline with sand, with FLUENT software, and then discuss the influence on erosion caused by the flow velocity of gas, the flow rate of sand, the diameter of particles and so on. The following conclusions are drawn: with the increase of natural gas flow rate, the average erosion rate at the tubing joint increases gradually and is approximately exponential to the natural gas flow rate; with the increase of sand flow rate, the average erosion rate at the tubing joint increases gradually and is approximately linear to the sand flow rate; with the increase of sand particle size, the erosion rate at the tubing joint decreases gradually.
Prediction of gas emission based on grey-generalized regression neural network
Authors: Chen Yanqiu , Zheng Linjiang , Huang Jing , Zou Zhe , Li Chunhui 
Published: April 2020

Abstract
Coal mine gas is one of the main factors endangering mine safety in China, and the amount of gas emission is affected by a variety of related factors, which have the characteristics of non-linearity and uncertainty. In order to predict gas emission more quickly and accurately, a coupling algorithm of grey theory (GM (1,1) and generalized regression neural network (GRNN) is proposed. Thirteen parameters, such as coal seam gas content, depth and GM (1,1) gas emission prediction value, are used as input of the model. The input parameters are normalized and used as training and testing samples of the model. The 10 fold cross validation and minimum root mean square error (RMSE) are used to find the optimal smoothing factor (spread), then a non-linear prediction model of gas emission is established. The gas monitoring data of Qianjiaying Mining Area of Kailuan Mining Group from May 2007 to December 2008 are used in the experiment. The results show that the model has a great improvement in convergence speed and a good accuracy, which can provide theoretical basis for the prevention and control of coal mine gas disasters.
Study on the preparation of composite MnO2
Authors: Qing Hui , Xu Su , Kuang Huizi , Liao Wen Chao , Huang Xiaodong , Zhang Xiuxiu 
Published: April 2020

Abstract
The manganese dioxide (MnO2) is a material that has broad application prospects and economic value, which is used in various fields. However, the poor conductivity, less active sites and the easy collapse of the structure during the reaction, limit application. In this paper, three kinds of MnO2 were prepared by simple method, α-MnO2, β-MnO2, and γ-MnO2. And the properties of the sample were further analyzed by Brunauer-Emmett-Teller (BET), X-ray diffffraction (XRD), scanning electron microscopy (SEM), Energy Dispersive X-Ray Spectroscopy (EDX) and fourier transform infrared spectroscopy (FTIR). Then α-MnO2 was chosen as the precursor of this study. Three different ratios of transition metal Ni and Co are respectively loaded with α-MnO2. Electrodes made of 7 different samples including α-MnO2, complete cyclic voltammetry test. Results show that: (1) α-MnO2 is not easy to collapse and suitable for precursor; (2)the addition of metal Ni and Co increases the specific surface area of the material to varying degrees. Co@a-MnO2-2 has the highest specific surface area and porosity, which can provide more active sites when applied; (3)all seven samples have good capacitance characteristics. The best is Co@a-MnO2-0.5, but Co@a-MnO2-2 is very close to Co@a-MnO2-0.5. Comprehensive analysis, the best ratio for this study is Co@a-MnO2-2.
Study of wave load computation based on diffraction theory
Authors: Chen Zhi , Du Yu , Liu Yanjun , Liu Hengyu , Xue Gang 
Published: April 2020

Abstract
With the development of the ocean resources, the design of the offshore platform attracts increasing attention. The wave load computation is an important part for the design of the offshore platform. Currently, model experiments are mainly used to get the wave load of the offshore platform, which is complex, inefficient, and error-prone. To improve the efficiency of calculation, more simplified formulas for the wave load computation were deduced based on the wave diffraction theory. Moreover, a simple method was proposed based on the Matlab and software was developed to calculate the wave load. Experiments were conducted by a designed cylinder floater model to obtain the values of the wave load. Some simulations were made to calculate the wave load under the condition that water depth, wave frequency and other relevant parameters were same with the experiments. The wave load values calculated by the software had similar change trends with that of the experiment data, which proved the feasibility of the formulas for the wave load computation based on diffraction theory and the accuracy of the numerical algorithm in the computation of wave load based on Matlab. Compared with the model experiments, the software based on the diffraction theory was a cheaper and convenient way to obtain the values of wave load when the platform in the ocean is designed. So the new method will improve the efficiency in the wave load computation and is in favour of the design of offshore platform.
Robust day-ahead dispatch for combined heat and power microgrid considering wind-solar power uncertainty
Authors: Wang Xi , Deng Yingying , Ren Zhichao , Wang Haiyan , Chen Shi , Jia Chuyun , Ye Yanli 
Published: April 2020

Abstract
Due to the energy crisis and environment pollution, small-scale wind power and photovoltaics have been widely deployed in power system using microgrid (MG). Moreover, several researches have focused on incorporating various energy forms into MG. However, the uncertainties of wind power and photovoltaics may significantly impact the security and economy of the MG operation. To deal with this issue, this paper presents a two-stage robust model to achieve the optimal day-ahead economic dispatch strategy involving uncertain wind power and photovoltaics. The first stage decides the initial day-ahead dispatch strategy before the realization of uncertain wind power and photovoltaics. The additional adjustment action is made in the second stage as long as the uncertainties are observed. The column and constraint generation (C&CG) decomposition is employed to decompose the original model into the day-ahead dispatch master problem and the additional adjustment sub-problem. Based on the duality theory and Big-M approach, the sub-problem with complex max-min structure can be converted into a tractable mixed-integer linear programming (MILP) problem. Therefore, C&CG iteration algorithm can be further implemented to achieve the optimal day-ahead economic dispatch strategy for the MG. The experimental results of the comparisons to the deterministic optimization demonstrate the effectiveness of the presented optimization.
Development of fast simulation models of photovoltaic generation system based on MATLAB
Authors: Luo Shanshan , Chen Bing , Shi Mingming 
Published: April 2020

Abstract
Based on the mathematical model of photovoltaic power generation system, the simulation model based on MATLAB/Simulink is given. Traditional simulation models have the drawbacks of rapidity and poor robustness. In this paper, two equivalent simplified models based on inverters are established—the equivalent switch model and the average model. In this paper, the above three models are compared comprehensively from different aspects such as simulation speed, simulation precision and robustness, and the applicable occasions of each method are proposed.
Two-stage stochastic scheduling model of wind-photovoltaic-storage providing flexible ramp capacity
Authors: Huang Ruanming , He Xinqin , Zhao Jingjing , Fei Fei , Guo Mingxing 
Published: April 2020

Abstract
The increasing penetration of renewable energy resources in power system has contributed to the increasing demand for operation flexibility. To address the deficiency of flexibility in wind-photovoltaic-storage hybrid system with deepening penetration of intermittent and uncertain renewable energy resources, this paper proposes emerging flexible resources including wind, photovoltaic and energy storage providing flexible ramp capacity to improve flexibility. Considering the uncertainty of load and intermittent generation, the wind-photovoltaic-storage providing flexible ramp capacity are integrated into a two-stage stochastic dispatch model including 1h day-ahead unit commitment and 15min real-time economic dispatch. To test the efficiency of the proposed model, simulation are carried out on a modified IEEE 118-bus with 54 thermal units, the results indicate that wind-photovoltaic-storage providing flexible ramp capacity can effectively alleviate the deficiency of operation flexibility, and improve the overall economic benefit.
A new approach to reduce AC grid for coupled HVDC systems
Authors: Dou Fei , Wang Weiyuan , Xu Yiqing , Wang Lijun , Yu Xuan , Xue Jiliang 
Published: April 2020

Abstract
When the dynamic performance study of the HVDC system are carried out or the over voltage characteristics is analysed, electromagnetic transient simulation is needed. The reduction of the AC system is inevitable since the computation burden is huge taking the whole ac grid as well as detailed HVDC models into account. Because the task is to maintain the dynamic response of AC system in a short term and focuses inside the HVDC transmission system, reasonable reduction of the ac grid can be done to simplify this problem without effecting the analysis conclusion. However, the existing approaches to reduce large ac grid aims to analyse the transient stability under asymmetric faults. In these methods, the remaining ac grid is still too large considering full HVDC models which is usually represented by simplified ones. In order to solve the specific aforementioned problem, multi-port Thevenin equivalent is adopted to simplify the original large power grid. By the transient stability simulation and short-circuit calculation, the node impedance matrix can be obtained. According to the admittance matrix obtained by the impedance matrix, the structure of the equivalent system as well as the impedance of the source are determined. The power flow of the equivalent system approximates that of the original system based on the quadratic programming. A UHVDC hierarchically connecting to girds of two voltage levels i.e. 500 kV and 1000 kV is taken as an example, which verifies the validity of the proposed method. Given the relatively small scale of the reduced system, further study on the full HVDC system can be done under computational constraints.
Simulation analysis of boiler high temperature corrosion atmosphere under lean oxygen operation
Authors: Xu Hong , Xu Weigang , Tan Houzhang 
Published: April 2020

Abstract
High-temperature corrosion is a major threat to the safe operation of thermal power plants. The reducing atmosphere induced by boiler lean oxygen combustion has close relation with the water walls corrosion. In this paper, the reducing atmosphere such as CO, H2S concentration distribution was simulated targeted on a boiler. Under the full load, the atmosphere and the temperature distribution in low nitrogen combustion mode were further studied on different excess air ratios and the rates and position of the SOFA air conditions. With the SOFA rate increasing, the flame centre moved up, the boiler temperature is more uniform, and the temperature at the furnace outlet increased. the concentration of CO and H2S in the main combustion zone is obviously increased. In the burnout zone, there is almost no CO and H2S due to the supplement of SOFA.
Risk-based configuration of current limiters in large scale power systems
Authors: Li Zong , Kuai Shengyu , Xia Kai , Yang Mengmeng , Feng Peiru , Shen Yuming , Wang Jiaqing , Tian Jia 
Published: April 2020

Abstract
The short-circuit current level has become the most prominent constraint for composite power grid. Consequently, it is of unprecedented necessity to adopt specific measures to limit the short-circuit current levels in transmission network planning. A multi-objective model is proposed in this paper to configure current limiting measures. The proposed model is risk-based which considers both the occurrence probabilities and consequence severity levels of short circuit events. NSGA-II is utilized to solve the Pareto proposed model, which provides a Pareto set of optimal current limiting solutions, rather than a single solution. This proposed method effectively enhances both the cost-effectiveness and decision flexibility in current limiting planning.
Vibration fault diagnosis and dynamic balance processing analysis of blower in thermal power plant
Authors: Li Peng , Pang Le , Lin Zhongpeng 
Published: April 2020

Abstract
The fan vibration of the forced draft fan in a power plant is too large during normal operation, which seriously affects the normal operation of the unit. Through the vibration detection, on the basis of comprehensive analysis of the fan vibration failure mechanism, the means of adjusting the balance of the fan is adopted to reduce the excessive vibration to an excellent level. This paper introduces an excessive vibration fault caused by a device imbalance problem that is treated by vibration detection and dynamic balance test. The article elaborates the diagnosis method, diagnosis process and treatment suggestions, and deeply analyses and summarizes the characteristics of rotor imbalance, and provides reference for the diagnosis and analysis of the same type of fault.
Evaluation of the peak-shaving capability of the receiving-end power system with multi-infeed UHV
Authors: Wu Huahua , Yin Xunhu , Zhu Bingquan , Shen Shaofei , Zhou Xiaoming , Guo Libang , Ding Yi 
Published: April 2020

Abstract
Peak-shaving capability mainly refers to the capability of the power system to maintain the balance between the active output and load balance in real-time. Sufficient peak-shaving capability is one of the important conditions to ensure the security and stability of the power system. The access of multi-infeed ultra-high voltage will largely weaken the peak-shaving capability of the power system and thus increase its peak-shaving pressure. This paper first introduces the characteristics of renewable energy generation such as wind generation and photovoltaic generation since a large amount of renewable energy from the sending-end system through several UHV delivery often increases the peak-shaving pressure of the receiving-end power system. On this basis, it analyses the impact of multi-infeed UHV on peak-shaving of power system. Then, an evaluation method that uses equivalent peaking capacity to measure the peak-shaving capability of the UHV receiving-end power system with multi-infeed UHV is proposed. Finally, Zhejiang Power System is used as an example to evaluate its peak-shaving regulation capability in the typical years and the typical day using the proposed method.
Study on operation status of SCR denitration system in Chinese coal-fired power plants
Authors: Zhang Yang , Feng Qianwei , Li Sha , Xu Ketao , Pei Yukun , Zhu Yue 
Published: April 2020

Abstract
Since the beginning of the 12th Five-Year Plan, coal-fired power plants have carried out large-scale denitration and ultra-low emission transformation in China, among which SCR denitration technology is the most widely used. However, some hidden problems in the process of project implementation have gradually emerged after operation due to various factors, such as the centralized reconstruction task, lack of technical experience, inadequate quality control of main equipment, uneven quality of denitration catalysts, and insufficient operation and maintenance experience of power generation enterprises. In this context, the future direction of SCR denitration operation and maintenance management is proposed after a systematic summarization and analysis of the operation status of SCR denitration system in recent years to provide reference for subsequent work.