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Table of Content

    05 February 2018, Volume 51 Issue 2
    Experimental Study on the Load Bearing Capability of Oblique Pyramid Eccentric Assembled Foundation in Transmission Line
    ZHANG Qiang, ZHENG Weifeng, ZHAO Qingbin
    2018, 51(2):  1-6.  DOI: 10.11930/j.issn.1004-9649.201604144
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    Through modifications and improvements in layout type of scaffolds and connection mode, the eccentric assembled foundation consisting of concrete laths and angle steel scaffolds can improve foundation force bearing and effectively save steel consumption. Real-model tensile and compressive tests are conducted on the backfill clay along direction of main member and diagonal member of tower leg. Through analysis of load displacement curves, steel bracket stress strain relationship, surface cracks and base soil pressure distribution law, mechanical performance and fault status are tested and verified. The ultimate tensile bearing capacity of the eccentric assembled foundation is 1.5 times that of the design value, and the ultimate compressive bearing capacity is 1.8 times. The basic structure is still in elastic state and can meet design requirements under those conditions. The results can provide reference for future engineering applications in transmission line.
    Analysis on the Leakage Current on the Composite Insulator Surface with Corrosion Product Fouling
    ZHAO Meiyun, WU Yang, ZHAO Xinze, PENG Wenyu, XI Senming
    2018, 51(2):  7-12,53.  DOI: 10.11930/j.issn.1004-9649.201706011
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    In order to study the relationship between leakage current and composite insulator surface with corrosion product fouling, samples are prepared by artificial pollution test method, and the leakage current testing equipment are used to measure the leakage currents of samples by taking the pollution time, salt density, ash density and pH value as variables, and the influences of the variables on the leakage current are analyzed. The results show that the leakage currents on the composite insulator surface increase with the corrosion time, and the influence on leakage currents in the acidic environment is greater than that in alkaline environment; compared with ash density, influence of salt density change on the leakage current is more obvious, and the leakage current increase with the increase of the voltage and the applied voltage time.
    The Numerical Analysis on Temperature Rise Multiphysics Coupling of GIS Disconnector Contacts
    ZHOU Tian, LI Zipin, SHEN Quanyu, SHU Naiqiu, WU Yuanchao
    2018, 51(2):  13-20.  DOI: 10.11930/j.issn.1004-9649.201612013
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    The overheat fault of gas insulated switch-gear (GIS) disconnector contacts severely damages the reliable operation of equipment. In order to monitor the temperature rise and the overheat fault of GIS disconnector contacts, this paper establishes a 3D numerical coupled multi-physics model of eddy current-fluid-temperature of GIS with contacts. The resistance of contactor is replaced by a conductor with variable resistivity, and the current density and power loss of GIS disconnector are calculated through analyzing the electromagnetic field. The temperature of conductor and tank are calculated by using the finite element model whose heat source is power loss. The inversion law and influence factors of the temperature rise of GIS disconnector contacts are studied based on the coupled multi-physics model. The results show that the relationship between the contact of phase A, B and the temperature rise of tank is 1:0.215, and the relationship between the contact C and the temperature rise of tank is 1:0.165. The research results can provide theoretical basis and technical support for monitoring the temperature rise of GIS.
    Development and Application of A New Partial Discharge Detection System
    HUANG Xiangxin, KONG Ming, LIU Zhenshan, SHI Zhiming
    2018, 51(2):  21-26.  DOI: 10.11930/j.issn.1004-9649.201612116
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    To solve the problem of difficulty and low efficiency in partial discharge detection, a new system for partial discharge detection is designed and developed. It uses Internet of Things to realize graphical collection at front-end, transmission of wireless ad hoc network and real-time monitoring, while supporting information check at mobile-end. In the laboratory, the GIS device is simulated to test the system's performance. The experimental results show that the system can accurately display the discharge signal and ensure the quality of detection. Meanwhile numerous on-site detections are conducted to analyze the abnormal partial discharge signal so as to improve the efficiency of work.
    Target Edge Detection of Aerial Photography for High-Voltage Transmission Lines
    ZHAO Jiangman, MENG Jianliang
    2018, 51(2):  27-32.  DOI: 10.11930/j.issn.1004-9649.201605007
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    In this paper, image features are analyzed for high voltage transmission lines under various circumstances and then a method combining LoG operator and morphology is proposed. The gray image histogram shows that this method can not only present two peaks well, but also exhibit better performance finding the optimal threshold segmentation points. Compared with the improved Otsu (maximal variance between clusters) image segmentation algorithm, this method makes it easier to separate the target from the background. Matlab simulation results show that the proposed method can successfully detect the contour edge of the target in the image regardless of environment impact of high voltage transmission lines. It is still effective even under the influence of certain severe natural environment conditions.
    Research on SO2 Online Monitoring Device of SF6 Electrical Equipment
    WEI Jing, MO Xiaoxiang, CHENG Fengzhi, DING Wuxing
    2018, 51(2):  33-38.  DOI: 10.11930/j.issn.1004-9649.201612089
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    Online monitoring for SO2 and its trend has important significance for fault pre-warning and analysis of SF6 electrical equipment. Based on ultraviolet fluorescence method, an online monitoring device is designed including SO2 UV fluorescence optical path system, detection circuit, software and online lossless gas sampling system. The online lossless gas sampling system has many merits including automatic sampling, gas recovery, gas wastage, leakage and pollution prevention and multiple decomposition gases detection. Experimental test results and field operation show that proposed device can satisfy needs of online SO2 monitoring of power equipment.
    Research and Application of Power Grid Fault Integrated Analysis and Smart Alarm Based on Multi-Data Source Fusion
    YAN Bo, ZHANG Hao, GUO Ziming, WANG Dongsheng, LIU Meng
    2018, 51(2):  39-46.  DOI: 10.11930/j.issn.1004-9649.201611088
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    With rapid development of ultra-high voltage (UHV) power grid in China, a single fault may lead to serious blackout accidents. However, existing fault alarm functions cannot meet power grid dispatching requirement. A fault analysis mechanism based on combination of alarm reliability and data availability is established to compress, fuse, filter and abstract alarm data from various data sources. The improved fault alarm analysis results are visualized and easily accessible by operators. Application results show that proposed smart power grid alarm techniques can significantly improve both alarm reporting rate and accuracy. It provides powerful support for power grid fault prediction and processing.
    Application of 500 kV UPFC in Suzhou Southern Power Grid
    YANG Lin, CAI Hui, WANG Weiyuan, SONG Pengcheng, XU Zheng, CHEN Gang, DOU Fei
    2018, 51(2):  47-53.  DOI: 10.11930/j.issn.1004-9649.201701107
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    An introduction is made in this paper to a 500 kV unified power flow controller (UPFC) demonstration project, which is implemented in Suzhou southern power grid and is scheduled to be put into operation by the end of 2017. The UPFC project will be of the largest power capacity and the highest AC voltage level of all UPFC projects in the world. The overview of the Suzhou southern power grid and its existing problems are firstly introduced, and the difficulties for implementing conventional solutions (e.g. upgrading existing transmission lines and constructing new transmission lines) are also addressed. Then, the UPFC solution are discussed, including the project scheme, the effectiveness of the solution, the implementation difficulties and the investment cost. Finally, the economic and social benefits of the 500 kV UPFC project are demonstrated though technical and economic comparisons. The analysis shows that the UPFC project, which has smaller implementation difficulties and better economic benefits than conventional solutions, can effectively alleviate the operation problems of the Suzhou southern power grid, such as limited power supply capacity, insufficient reactive power support, and high risk of commutation failures. The project is of demonstration value to the application of UPFC in higher voltage projects.
    A Method for Load Forecasting Based on Correlated Fuzzy Neural Network and Improved Artificial Bee Colony Algorithm
    ZHAO Zhipu, GAO Chao, SHEN Yanxia, CHEN Jie
    2018, 51(2):  54-60.  DOI: 10.11930/j.issn.1004-9649.20160252
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    To improve the accuracy of load forecasting, a load forecasting model is proposed by using correlated fuzzy neural network (CFNN) with consideration of the correlation between the historical load data. An improved artificial bee colony (ABC) algorithm is applied for the parameter identification of the model to reduce the number of fuzzy rules and decrease the complexity of the model. The model is applied to actual load forecasting, and the results show that this model has higher prediction accuracy.
    Utilization Evaluation of Power Grid Equipment Considering Regional Differences
    GUAN Yuheng, WANG Longjun, SUN Chuan, ZHANG Yue, ZHANG Junxiao
    2018, 51(2):  61-66.  DOI: 10.11930/j.issn.1004-9649.20150213
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    Due to the unbalance of social and economic development and the differences of regional features and statistical data quality, the utilization evaluation of power grid equipment lacks homogeneous base, and the fairness of the evaluation results is affected. A three-stage approach for utilization evaluation of power grid equipment is put forward. The approach first applies the data envelopment analysis model which has variable returns to scale in order to solve the input variable slacks. Second, the environment variables are used to fit the slacks with regression for adjusting the input variables. The adjusted input variables are substituted into the data envelopment analysis model to achieve the evaluation at last. It is demonstrated that 1) the traditional data envelopment analysis does not consider the environmental factors, which leads to the underestimation of the power grid equipment utilization in underdeveloped regions; 2) environmental factors have significant influences, which are reflected in the power grid equipment utilization; 3) the three-stage method can evaluate the power grid equipment utilization more truly and fairly.
    Smart Grid Value-Added Business Survey and Customized Service
    WANG Kaijun, ZHENG Weimin, SUN Ke, JIN Kangmeng, ZHANG Pei
    2018, 51(2):  67-74.  DOI: 10.11930/j.issn.1004-9649.201706001
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    Smart grid value-added business include intelligent electricity services, electric vehicle charging, Fiber To The Home (FTTH) and public information service. These services have gradually integrated with customers' daily life. Customer information and needs for different smart grid value-added services are collected through internet surveys. Based on characteristic and requirement analysis, customized services for different types of consumers are proposed in order to meet personalized needs and increase customer comfort level.
    Design and Application of Robot Inspection System in Substation
    PENG Xiangyang, JIN Liang, WANG Ke, QIAN Jinju, YUE Weibing
    2018, 51(2):  82-89.  DOI: 10.11930/j.issn.1004-9649.201701134
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    This paper develops a robot intelligent inspection system for substations, and presents the design scheme and key technologies of the inspection system in terms of the robot body, charging system, wireless transmission system, local monitoring background and the environment adaptability. An introduction is made to the engineering implementation steps of the system in terms of site investigation, equipment installation, and inspection planning and application, and its practical applications in 220 kV and 500 kV substations. At the same time, the paper also presents the problems in the process of robot inspection and debugging, such as the derailment during travelling, unstable wireless communication, inaccurate meter reading, and difficult turning around the corner, and proposes corresponding solutions. With such significant advantages as quick deployment, strong adaptability, accurate data collection, high positioning accuracy, and ultrasonic anti-collision, this system can meet the requirements of substation intelligent inspection in all functions and has good application prospects.
    Multi-Objective Fuzzy Optimization for Reactive Power of Distribution Network Based on Immune Particle Swarm Optimization Algorithm
    SITU You, WU Jiekang, GUO Qingyuan, WU Changyuan, WANG Zhengqing, XU Honghai
    2018, 51(2):  90-98.  DOI: 10.11930/j.issn.1004-9649.201702017
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    Considering the influence of intermittent and randomness of distributed energy on the voltage of distribution network, the fuzzy power is used to characterize the fluctuation of distributed power output and load power. The multi-objective fuzzy and reactive power optimization model of distribution network is proposed in this paper. Besides, the coordinated optimization method is introduced for the output reactive power of distributed generations and reactive power compensation devices. By taking the minimum loss of power network and the smallest voltage deviation as objective function, the objective function and the constraint conditions are fuzzified, and the fuzzy fitness function is formed according to the membership function. Then, the multi-objective optimization problem is transformed into the single objective optimization by the maximum satisfaction method. Finally, the immune particle swarm optimization algorithm is used to determine the optimal value of the output reactive power of the distributed generations with different fuzzy output levels and the reactive power compensation device with different operating modes under fuzzy fluctuations of the load powers. By taking the IEEE33 distribution system as an example, the feasibility and validity of the proposed model and algorithm are verified.
    Research on Capacity Optimization of Pumped-Storage Power Station with Wind Farm
    YI Chen, REN Jianwen, YU Jia
    2018, 51(2):  99-104,124.  DOI: 10.11930/j.issn.1004-9649.201612076
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    Pump-storage capacity optimization is very important to improve wind farm operation economics. According to wind farm characteristics, an operation strategy of wind power-pumped storage system is proposed to reduce effect of wind fluctuations and randomness on system stability. A model is proposed to calculate reference value of wind farm output power, which is used by dispatcher to formulate generation plans. A stochastic optimization model for determining pumped-storage capacity is presented, which aims to minimize total cost of wind farm operation and pumped-storage installation and maintenance. The model is solved by chaotic particle swarm optimization algorithm. Analysis of examples show the effectiveness of proposed scheduling strategy.
    Solar Radiation Resources Estimation and Reliability Analyzing of NASA Data in Liaoning Province
    GONG Qiang, XU Hong, LIN Na, ZHU Ling, GU Zhengqiang, CHAO Hua, WANG Hongyu, SHANG Minshuai
    2018, 51(2):  105-111.  DOI: 10.11930/j.issn.1004-9649.201707115
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    Based on observation data of global solar radiation(GSR) at 3 meteorological stations and sunshine data at 55 meteorological stations during 1981-2014, distribution of solar radiation resources in Liaoning Province is evaluated. Reliability of GSR data from NASA in the same area is also analyzed. The annual mean GSR in Liaoning province is 4 950 MJ/m-2 with decreasing trend from northwest to east area. The maximum value of GSR(5 421 MJ·m-2) is in Jianping town located in the northwest of Liaoning, and the minimum value (4 506 MJ·m-2) is in Xinbin county located in east. The solar energy resources is stable. The number of continuous days without sunshine is less than 6 in most areas of Liaoning Province with increasing trend from northwest to southeast. The northwest region of Liaoning has the highest predominance in solar energy utilizing. Compare to observation data, the annual mean GSR from NASA data is significantly bigger (around 15%), which should be used cautiously.
    Anti-Typhoon Technology Research of Offshore Wind Turbine
    TAN Maoqiang, YANG Yuan, JIA Bin, LI Cong
    2018, 51(2):  112-117.  DOI: 10.11930/j.issn.1004-9649.20150043
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    Different from European offshore wind farm, typhoon seriously restricts offshore wind development in China. Based on aerodynamic analysis of offshore wind turbine in typhoon condition, wind pressure on blade, tower and turbine winding are calculated. Anti-typhoon cost is analyzed with IEC 61400 and GB/T 31519—2015, GB/T 18451.1—2012 standard requirement. Then measures of offshore wind turbine are proposed to improve typhoon resistance. Those measures include strengthen offshore wind turbine blade material, lengthen of retractable blade positioning mechanical arm to fix blade, change central tower structure from bolt connection to subsided upper tower and improved anti-typhoon control strategy. All those measures can help to build cost effective and practical anti-typhoon offshore wind turbine.
    Research on Comprehensive Optimization for Distribution Network with Micro-Grid
    WANG Yansong, SUN Minghong
    2018, 51(2):  118-121.  DOI: 10.11930/j.issn.1004-9649.201604052
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    The coordinated optimization of switches, tie lines and micro-grid connection point is a main method to narrow outage range, transfer loads and reduce outage cost when fault happens. The mathematic model of comprehensive optimization for distribution network is founded, which includes the cost of switches and tie lines along with user outage cost. The line segment is selected as basic unit in outage cost calculation. The comprehensive optimization is solved by co-evolutionary genetic algorithm. Key technologies and main flow of co-evolutionary genetic algorithm application are studied in distribution network comprehensive optimization. The economic comparison analysis results on IEEE33 node system and practical engineering projects distribution show the effectiveness of proposed algorithm.
    Economic Dispatch of Microgrid with Energy Storage under Different Price Policies
    LI Gang, LI Feng, KONG Liang, SONG Zongxun
    2018, 51(2):  125-132.  DOI: 10.11930/j.issn.1004-9649.201611039
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    In order to verify the role of energy storage in peak shaving and economic dispatch of power system under different price policies, the paper models the microgrid with energy storage. Firstly, a typical microgrid is built which contains the wind turbine, photovoltaic cell, combined power and heat system, boiler, fuel cell and energy storage system. Then, given the time-of-use (TOU) price and real-time price (RTP), an economic model is established with consideration of the heat sale profit, maintenance cost and power exchange cost between microgrid and grid, and is optimized with the Hybridize Invasive Weed Bat Algorithm (HIWBA). In addition, in order to verify the effectiveness of the proposed model and the reached conclusions, by taking to the economic dispatch model of microgrid without energy storage under two different price policies as a reference, the paper optimizes the optimal outputs and operation costs of the distributed generator units of a practical microgrid on a typical winter day. The results indicates that the energy storage can help regulate the peak load and reduce the operation costs, and different price policies have different impacts on cost reduction and the effectiveness of energy storage.
    Analysis on Actual Operation Performance of SCR Denitration Catalyst
    DU Zhen, WANG Zhidong, YAN Min, JIANG Jianping, ZHU Yue
    2018, 51(2):  133-136,155.  DOI: 10.11930/j.issn.1004-9649.201707159
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    The control of the actual operating performance of the catalyst is critical to the stable operation of SCR denitrification system. In this paper, the fresh catalyst and used catalyst after different time periods of operation in a power plant were taken as the research objects. The physical and chemical properties, mechanical properties, and microstructure of catalyst are tested, and its impact on the operation of the catalyst is analyzed. Through the study on the process characteristics and activity of the catalyst in operation, it is expected that the catalyst performance test will provide the basis for the replacement and installation of the denitration catalyst. The results show that after the catalyst having been installed and used for more than two years in the coal-fired power plant, operational risk has increased to certain level with the escaping rate of ammonia approaching the upper limit of the guaranteed value . In order to ensure the safe and efficient operation of the denitrification system, the catalyst management should be actively involved after being put into service.
    Numerical Simulation of the Distribution Discrepancies between Flue Gas Flow Field and Fly Ash Concentration Field in SCR De-NOx Reactor
    ZHUANG Ke, YAO Jie, WU Bijun, MA Xiuyuan, SHEN Yong, DU Meng, ZHONG Ping
    2018, 51(2):  137-142.  DOI: 10.11930/j.issn.1004-9649.201704088
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    Ash accumulation is one of the critical problems affecting the performance and secure operation of SCR de-NOx system in coal-fired power plants. Unfortunately, the fly ash concentration field is often neglected in traditional engineering design. In this paper, the ash accumulation states of a certain 600 MW coal-fired power plant was studied. The calculation model was established according to CFD method and the distribution of flue gas flow field and fly ash concentration in de-NOx reactor was simulated. Also a structure optimization was established to improve the distribution of flue gas and fly ash. The results indicated that the distribution characters of fly ash decreases with the increase of particle size and density of fly ash particles. The high concentration and density of fly ash particles can easily lead to the clogging of the catalyst layer, which may lead to the serious problem. The distribution of flue gas flow field and fly ash should be demonstrated to ensure the safe and efficient operation of the device when the fly ash concentration field is designed.
    Study on Operation Optimization of SCR Denitrification with Ammonia-Injection for Ultra-Low Emission
    FANG Zhaojun, LU Chengzheng, BAI Xiaolong
    2018, 51(2):  143-148.  DOI: 10.11930/j.issn.1004-9649.201701050
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    A 600 MW coal-fired unit with one more layer of backup catalyst is taken as an example in this paper to measure the NOx concentration distribution at the SCR reactor outlet, the NOx concentration deviation between the outlets of the SCR reactor and the FGD tower, and the concentration of ammonia slip, for the purpose of improving the operation quality of the thermal power plant after the ultra-low emission technical transformation. Some problems, such as the ammonia injection optimization and blocked ammonia branch nozzle dredging, are resolved and the corresponding adjustment is applied. The low NOx burner reformation decreases the NOx concentration at the SCR inlet. To avoid adverse effects due to excessive ammonia injection, it is suggested that the denitrification efficiency should be lowered accordingly, i.e. to control the ammonia injection to a certain level based on the NOx emission standard. The catalyst activity of the unit is evaluated, and the constraint indexes of catalyst replacement, installation or regeneration strategy selection are proposed.
    Application of the Four in One Type Desulfurization and Dust Removal Equipment in a 600 MW Unit
    CHENG Xinxing, LI Shuaiying, WU Baohui, NIU Guoping
    2018, 51(2):  149-155.  DOI: 10.11930/j.issn.1004-9649.201703004
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    The ultra-low emission of flue-gas pollutants reformation project on a 600 MW unit adopts gas tower integration technology, bringing the desulfurization tower, the wet electrostatic precipitator and the chimney in one indirect dry cooling tower (the 4-in-1 tower). In this paper, a scheme of ultra-low emission reform is introduced and the finite element method combining with the practical experience is adopted to optimize the 4-in-1 tower layout on the basis of structural calculation and analysis. Comparisons are made between the 3-in-1 scheme and the 4-in-1 one, also between the two different layouts of 4-in-1 tower, from the technological and economic perspectives. The vertical integrated layout for the desulfurization tower, the wet electrostatic precipitator and the chimney is adopted. The original desulfurization tower is reinforced also. The principle and method of the design for the over-limit high temperature elevator are introduced. Application results showed that the environmental protection facilities are working steadily . Operating with high, medium and low load levels and three types of coal quality, the average mass concentration of SO2 is about 9 mg/m3, and the average mass concentration of dust is about 3.38 mg/m3, demonstrating better benefit in energy saving and environmental protection .
    Experimental Study on the Technology of Large Particle Ash Interception for SCR De-NOx Equipment
    JIN Lipeng, XIE Xinhua, HUANG Fei, LU Chengzheng, ZHOU Jian, SONG Yubao
    2018, 51(2):  156-161,168.  DOI: 10.11930/j.issn.1004-9649.201611118
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    To solve the problem of LPA (Large Particle Ash) plugging in the SCR de-NOx equipment, the study on the technology of LPA interception is performed with the usage of the physical model based experiments. The effects of the hole pattern, the external structure and the mounting position of the LPA screen on its ash removal efficiency and the system drag force are analyzed. Multiple combination schemes of the dust hopper, the deflector and the LPA screen are compared for the best technical solution. The experimental results demonstrate that the ash removal efficiency of the LPA screen with rectangular opening is better than that with square or hexagonal opening. The drag force of the LPA screen varies inversely to the third power of the opening ratio. There is no obvious difference between the pleated and flat LPA screens in terms of the ash removal efficiency and the drag force. It is observed that the ash removal efficiency of the combination scheme of the deflector, the deep dust hopper and the low LPA screen is more than 95% when they are installed in the outlet of the economizer. The ash removal efficiency can be further improved when another dust hopper and a broken-line back wall are installed in the inlet of the vertical flue.
    Study on the Factors for Parallel Pipeline Flow Deviation in the Air Heater Collecting Headers
    XU Dangqi, HOU Xun, JI Haimin, ZHANG Zhixiang, ZHOU Fei, ZOU Xiaogang, ZHAO Zhiping
    2018, 51(2):  162-168.  DOI: 10.11930/j.issn.1004-9649.201611005
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    The low temperature economizer and air heater combined cycle system can improve the efficiency of the power plant boiler effectively and avoid blockage of the air heater system. Its application on the boilers in some power plants has been proved positive. However, the problem of uneven flow distribution is common in practice, which may result in the cracking of the heat exchanger tubes in winter in northern China, and harm the operation of the equipments. To better solve this problem, based on the mechanism of flow distribution of the working fluid in the air heater, this paper proposes a numerical calculation model on FLUENT software platform and a hydrodynamic calculation model on Visual Basic 6.0 platform. Results from the two models are compared. The influence of the heat load, the gravity and velocity of the working , the spacing between the heat exchanger tubes, and the location of collecting headers on the flow distribution in the heat exchanger tubes is analyzed. It is found that the uneven flow distribution is aggravated with the increase of the working fluid velocity. As the elevation of the collecting headers increases, the working fluid gravity plays a more important role and the uneven flow distribution is also aggravated. However, the increase of the velocity incurs a stronger forced flow in the collecting headers, which weakens the effect of the gravity. The coupled effect of the heat load and the gravity is the major cause of the uneven flow distribution in the air heater. Based on the calculation results, several schemes are proposed to prevent the uneven flow distribution. The results of this paper provide some solid technical backup for a better design of an air heater and solve the problem of tube cracking inside the air heaters due to low temperature.
    Analysis on Primary Frequency Regulation of 1 000-MW Double-Reheat Ultra-Supercritical Units
    XU Xing, TAN Rui, LI Yongsheng, CAI Pei, HUANG Qilong, MA Xiaofeng
    2018, 51(2):  169-175.  DOI: 10.11930/j.issn.1004-9649.201708148
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    In this paper, through the analysis on the primary frequency regulation performance of 1 000-MW double-reheat ultra-supercritical units, the major factors affecting the primary frequency response of double-reheat units are expounded from the aspects of furnace characteristics, control strategies and operation modes. Moreover, the impact of frequency modulation on the unit coal consumption rate using main steam regulating valve throttling is evaluated for a 1 000-MW ultra-supercritical double-reheat unit. Based on the feasibility analysis of throttling frequency modulation, condensate frequency modulation and feed water frequency modulation, the method to improve the primary frequency regulation capability of 1 000-MW ultra-supercritical double-reheat units is discussed in order to provide reference for the design and operation of the double-reheat units in the future.
    Dynamic Characteristics Analysis on a Dual-Pressure Natural-Circulation Gas Turbine Heat Recovery Steam Generator
    WANG Yaou, TAO Qian, CHEN Bo, GUAN Shipian, ZHANG Enxian
    2018, 51(2):  176-184.  DOI: 10.11930/j.issn.1004-9649.201705083
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    In order to better understand the dynamic characteristics of the dual-pressure natural-circulation gas turbine heat recovery steam generator, the lumped parameter method is used in this article to build a dynamic simulation model of a dual-pressure natural-circulation gas turbine heat recovery steam generator in Matlab/Simulink according to the principle and structural characteristics of the boiler, with the tube bank heat transfer in full consideration. The dynamic response characteristics of the main parameters are simulated with 10% perturbation of engine exhaust gas flow and its temperature, and the high-pressure feeding water flow. The results indicate that the engine exhaust gas temperature influences the steam parameters the most, the exhaust gas flow has less effect on them, high-pressure feeding water flow the least. The simulation results fit the practical operation data well, meaning that the model has high precision and good versatility, and can provide a reasonable technical reference for the same type boilers on thermal operation.