Table of Content

05 May 2020, Volume 53 Issue 5

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Multi-scenario Load Combinatorial Optimization Based on Improved Greedy Algorithm

WANG Yan, JIANG Jing, HE Hengjing, GAO Ciwei, XIAO Yong

2020, 53(5):  1-9.  DOI: 10.11930/j.issn.1004-9649.201812087

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With the gradual formation of sales side market competition pattern, the electricity companies can improve the safety level of power grid and the quality of power supply through load combinatorial optimization to improve the load rate and reduce the cost of electricity purchase on the users side, and to improve the equipment utilization rate and reduce the line loss on the power supply side. In order to integrate and optimize user resources according to the complementarity and diversity of power load, a user load combinatorial optimization model is proposed respectively for the scenarios of maximum purchase and sale benefits, maximum electricity transaction, and maximum comprehensive load rate based on the analysis of user load characteristics. And then, the greedy search algorithm is improved by introducing random factors to remedy the defects of the algorithm in determination of the initial estimation and optimization effects, thus improving the quality and accuracy of the algorithm. Finally, the improved greedy search algorithm is used to solve the load combinatorial optimization model under different scenarios. The improved algorithm has been verified to have stronger global search ability and adaptability in solving the combinatorial optimization problems.

Research on Reducing Regional Outage Loss Based on Entropy Weight-Gray Correlation Analysis

HAN Jun, HAN Wenhua, CHEN Xi, WANG Na, CHE Qianqian, SU Xiaoyan

2020, 53(5):  10-17.  DOI: 10.11930/j.issn.1004-9649.201812032

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Outage loss is one of the indicators to measure the economics of the power grid. Reasonable estimation of outage loss can provide a basis for improving distribution network reliability, social emergency power distribution, and public preventive budget allocation. In order to improve the accuracy of the grey relational analysis method, the ratio of output value to unit electric energy consumption (ROVUE) is used to calculate the outage loss, and the objective weight of each influencing factor is obtained with the entropy weight method. By using the method of entropy Weight-Grey correlation analysis, the correlation degree between the regional ROVUE and each industry, and the correlation degree between the reliability of distribution network and its influencing factors are calculated, respectively. In the case study of four different regions, the correlation of regional outage loss and various industries as well as the relationship between regional distribution network reliability and various influencing factors are analyzed. Thus the key direction and focus area are proposed for each regional power grid to upgrade its equipment, so that the investment of power supply enterprises can be concentrated to maximize the reliability of the distribution network and reduce the power outage losses.

Multifunctional Vehicle Inspection Technology Based on Full-Automatic Tracking

WANG Haipeng, WEN Yan, LI Jianxiang, ZHOU Dazhou, YANG Shangwei

2020, 53(5):  18-23.  DOI: 10.11930/j.issn.1004-9649.201812091

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At present, the manual patrol mode is widely used for distribution line inspection, which has such problems as time-consuming, poor quality, defect- omission, and error-prone records. To resolve these problems, a research is made on the multifunctional vehicle inspection technology with full-automatic tracking, and a distribution network vehicle inspection system is designed. The system uses the patrol vehicle as mobile platform, which is equipped with compound-eye probe of multifunctional detection module and vehicle control center based on intelligent edge algorithms. It can realize automatic line tracking, data synchronization acquisition, on-site analysis of defects, and real-time data transmission. The system has been applied in distribution lines inspection and all the functions have reached the expected objective.

Optimal Operation of Microgrid Based on Improved Particle Swarm Optimization Algorithm

ZHANG Shaoming, SHENG Siqing

2020, 53(5):  24-31.  DOI: 10.11930/j.issn.1004-9649.201811025

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Microgrid is an effective way to integrate the distributed generations, and the optimal operation of microgrid has become one of the important topics in the research of microgrid. The optimal operation of microgrid is modelled with a consideration of multiple operation indicators such as the economic cost, environmental cost, network loss and node voltage fluctuation, and a balance of the interests of various stakeholders. The elite reverse learning strategy and the worst particle exclusion method are introduced into particle swarm optimization algorithm (Particle Swarm Optimization, PSO) to solve the multi-objective and multi-constraint optimal operation problems of microgrid. In the process of searching, chaotic disturbance is made on the existing optimal particle to enhance the local searching ability, and to improve the ability of particle to jump out of local optimal solution. Under same conditions, the optimal operation model of the microgrid is solved using the original algorithm and the improved algorithm respectively, and the superiority of the improved algorithm is verified by comparing the solution results.

Reliability Assessment of Large Scale Security and Stability Control System Based on Control Efficacy Reduction Mode

LI Bijun, DONG Xijian, YAN Yunsong, XIA Haifeng, LIU Tianyi

2020, 53(5):  32-38.  DOI: 10.11930/j.issn.1004-9649.201908107

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Large-scale security and stability control system (SSCS) is characterized with wide-area distribution, multi-layer control, numerous components, and complicated function realization. The conventional reliability assessment indicators, such as malfunction rate, rejection rate, and failure rate, are too general to accurately measure the reliability level of SSCS. Based on the constitution of SSCS, the local abnormal forms are classified. In view of engineering application, the control efficacy reduction modes of SSCS are also classified, and the reliability indicators are further defined based on the control efficacy reduction modes. To assess the reliability of SSCS, the expected abnormal sets are firstly established, and then their induced control efficacy reduction modes and corresponding probability of occurrence are analyzed. The practical application indicates that the proposed reliability indicators, clear in definition, simple in calculation method, and flexible in assessment content and scope, can be used to study the effects of such factors as the architecture, the configuration and constitution of devices, the operation modes, and the operation logic and mechanism of core functions, on the SSCS reliability. The results of this research can provide an important basis for improving SSCS reliability.

Key Lines Identification in Power Grid Based on Comprehensive Index Calculated by the Entropy Weight-Analytical Hierarchy Process

WU Hao, ZHU Ziwei

2020, 53(5):  39-47,55.  DOI: 10.11930/j.issn.1004-9649.201909008

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In order to accurately identify the key lines of the power grid, the paper firstly proposes the Theil entropy of voltage variation and power flow variation based on the Theil entropy theory, in view of the state of the power grid and with consideration of the types of grid nodes and line load rate. The maximum flow contribution betweenness and average closeness index is proposed, so as to make the evaluation results more consistent with the complex network and the actual grid structure model. the entropy weight method and the analytic hierarchy process are used to determine the weight of indexes, and the comprehensive evaluation index of the key lines are obtained, which not only takes into account the changes of the power grid state and the power grid structure, but also the objective data and subjective experience. The feasibility and practicability of the proposed comprehensive index are verified through the IEEE 39-bus system.

Design and Application of Full-Time Dimension Dispatching Schedule Safety Check

WU Di, WANG Zhengfeng, LIU Hang

2020, 53(5):  48-55.  DOI: 10.11930/j.issn.1004-9649.201908143

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With the increasing of power grid scale and advancement of power market, the safety and reliability of power grid operations are facing increasing challenges, and the safety check of power generation schedules becomes particularly important. Under large time-scale, it is almost impossible to accurately predict the load and grid structure, so it is difficult to conduct safety check accurately. To solve this problem, this paper designs and develops a safety check system of full-time dimension dispatching schedule. It firstly discusses the monthly, weekly and day-ahead safety check functions according to the power dispatching process, and then proposes the full-time (monthly, weekly and day-ahead) dimension safety check goals. The monthly target is based on the completion of power generation plan and the coordinated optimization of power generation and transmission. The weekly target is based on the optimization of generator start-up mode. The day-ahead target is based on the power generation schedule. For the monthly safety check, a power generation feasible domain is constructed based on the power flow section, and the generation feasible range is optimized to compensate for the error of monthly load forecast. For the weekly safety check, the generator start-up mode is determined through optimization. For the day-ahead safety check, the output of generator unit is optimized. The system has been successfully applied in Anhui Power Grid, and the application results show that the proposed method is effective and can meet the needs of power grid safety check.

Study on Burnout Mechanism of TE Board for HVDC Transmission Project Electric Triggered Converter Valve

WANG Zhen, LIU Kun, JU Wei

2020, 53(5):  56-62.  DOI: 10.11930/j.issn.1004-9649.201810028

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Thyristor electronic board (TE board) of HVDC converter valve is an important equipment of HVDC converter valve. In the process of operation and maintenance, TE board burned out many times, resulting in the shutdown of the converter valve pole, which affects the safe operation of HVDC project seriously. This paper studies the TE board resistor burnout event in Tian-Guang HVDC project. Firstly, the appearance and electrical performance of TE plate are inspected. The damaged area of internal circuit of components is confirmed by X-ray detection and scanning acoustic microscopy, and the function modules of TE board which belong to each damaged component are also confirmed. Then, the burning reason of TE board faulty components is analyzed by circuit principle method, and the burning mechanism of TE board is speculated. The process of TE board burning failure is reproduced through experiments to verify the assumed mechanism for TE board burnout. Finally, the cause of TE board burning is obtained. The analysis method has reference significance for the analysis of similar board failure in HVDC project.

AC Discharge Characteristics of Rod Plate Gaps in Sand Dust Environment

WANG Jian, TU Zhifei, ZHANG Zhuoyu, HE Zhenghao, DENG Heming

2020, 53(5):  63-68,88.  DOI: 10.11930/j.issn.1004-9649.201812134

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In recent years, the influence of sand and dust on the external insulation of power system can not be ignored, but there are few studies about that at present. In order to study the discharge characteristics in dust environment, the tip-to-plate gap is employed. A sand-dust simulation experiment platform is built to carry out the AC discharge characteristics test. The effects of gap distance and dust duty ratio on AC discharge in tip-to-plate gap are obtained. The results show that when dust duty ratio is small, AC breakdown voltage in tip-to-plate gap decreases with the increase of dust duty ratio. While AC breakdown voltage in tip-to-plate gap increases with the increase of dust duty ratio when dust duty ratio is large. Therefore, it can be considered that there exists a certain duty cycle of sand and dust (about 1%), which minimizes the breakdown voltage of AC gap. It is found that the duty cycle is independent on the gap distance. Furthermore, the simulation model of tip-to-plate electrode gap is built in the finite element simulation software FlexPDE, and the flashover mechanism of tip-to-plate gap in dust environment is analyzed.

Design of GaN-Based Domino Wireless Power Supply System for High-Voltage Lines

TANG Niang, TAO Bingquan, QU Haoyue, HU Meilin, CAI Changsong, HUANG Mingxin

2020, 53(5):  69-76.  DOI: 10.11930/j.issn.1004-9649.201906031

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In order to solve the problem of power supply for tower monitoring equipment in high-voltage complex electromagnetic field environment, this paper proposes a GaN-based domino relay-type wireless power supply system and configuration method. Firstly, based on the circuit mutual inductance coupling model and finite element simulation, the frequency characteristics and power characteristics of the domino wireless power supply system are analyzed. It is found that by adjusting the load impedance matching and appropriately increasing the driving frequency, the transmission efficiency characteristics and frequency offset characteristics of the system can be effectively improved. And combined with the electric field distribution cloud map, the electromagnetic compatibility of the system is verified. Based on this, a prototype of the GaN-based domino wireless power supply system is built. The test results show that the system can realize high-voltage level, long-distance, high-efficiency wireless power supply, and has good anti-frequency offset characteristics, which provides a reference for the application of wireless energy transmission technology in the field of high voltage equipment power supply.

Stochastic Optimal Power Flow of Wind Turbine through Flexible Grid Connected System Considering Converter Loss

DU Jiahui, WANG Changjiang, LI Ling, YANG Chenguang

2020, 53(5):  77-88.  DOI: 10.11930/j.issn.1004-9649.201808166

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Because of the randomness and volatility of wind power, large-scale grid-connection will bring great challenges to the safe and stable operation of power systems. Therefore, it is necessary to deeply study the stochastic optimal power flow of wind power through (VSC-HVDC) grid-connection system. In this paper, a stochastic optimal power flow model for wind power through flexible DC grid-connected system is presented, which takes into account converter loss and wind power randomness. Firstly, the mathematical model of wind power and the VSC-HVDC mathematical model considering converter loss are established, and different control methods of the converter stations are analyzed when wind power is grid-connected. Secondly, scenario method is used to simulate the uncertainty of wind power, and Kantorovich distance based scenario cutting technology is used to improve the calculation efficiency. Thirdly, the stochastic optimal power flow model of wind power through the flexible DC grid-connected system is constructed, and the model is solved by the interior point method, and the numerical characteristics of output variables are obtained by using the statistical method. Finally, taking the modified WECC 2 machine 5 node and IEEE-118 node system as examples, the calculation example is analyzed to verify the rationality and validity of the proposed optimal model.

Research on the Disturbance Observer Based Generalized Wind/Solar Intergration Control Strategy

ZHANG Xuemeng, WANG Rui, MA Dazhong, DU Kai

2020, 53(5):  89-99.  DOI: 10.11930/j.issn.1004-9649.201901112

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With the high proportion of distributed renewable energy sources, such as photovoltaic and wind power, connected to the micro-grid, the uncertainty of its power generation output brings significant pressure to the safe and stable operation of the micro grid. Based on this, a disturbance observer based on generalized wind/solar isomorphic model is proposed. Firstly, by establishing the analogy model between the state equation of the interface rectifier and the state equation of the photovoltaic interface Boost circuit, the equivalent model of the isomorphic photovoltaic/wind turbine with single input and single output is proposed, so that the wind turbine and photovoltaic can achieve the consistency of the generalized model. Secondly, in order to solve the problem of partially unknown state variables caused by the output uncertainties of distributed energy such as photovoltaic and wind turbines, a continuous-time disturbance observer is introduced to control the equivalent generalized Boost model. When the illumination or wind speed changes, the disturbance observer can quickly follow the change. At the same time, with the passage of time, the disturbance observer can achieve no-difference adjustment, so as to control the equivalent generalized Boost model. The purpose of eliminating the partial state unknown caused by disturbance is achieved. Furthermore, the output voltage, current and power of a stable wind/photovoltaic hybrid system can be obtained by using a voltage-current double disturbance observer, and the output can quickly reach the given value. Finally, the effectiveness and reliability of the proposed method are verified by simulation.

New Energy Regional Power Prediction Algorithm Based on Statistical Upscaling in Ningbo Region

WANG Wei, WANG Bo, ZHANG Jun, LU Chunliang, HE Xu

2020, 53(5):  100-111.  DOI: 10.11930/j.issn.1004-9649.201809133

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In order to monitor and dispatch the large-scale wind farms and photovoltaic stations for power grid, it is needed to predict the regional power of new energy. A regional power prediction algorithm is proposed based on sub-region partition and statistical upscaling. According to the historical data of 9 wind farms and 16 photovoltaic stations in Zhejiang province from April to September 2016, six different combination schemes are compared. The mutual information theory (MI) and the minimal redundancy maximal relevance principle (mRMR) are used to accumulatively (mRMR-A) select four representative stations or directly (mRMR-D) select nine representative stations. The weight of each representative site is trained by cuckoo search algorithm, and the regional power is determined by scaling up. It is found that the MI-mRMR-A-CS-4 and MI-mRMR-D-CS-9 algorithms have low prediction errors with their monthly root mean square error being 8.51% and 7.64% respectively. It is concluded that when the summer monsoon is prevalent in Zhejiang region, the representative stations are selected based on mRMR principle with MI used as the index, and then the cuckoo search algorithm is used to obtain the power prediction values of sub-regions, and the cumulative power prediction results of all sub-regions are the best for the final regional power prediction results.

Research on Development and Operation of Renewable Energy Generation in German

WANG Yuefeng

2020, 53(5):  112-121.  DOI: 10.11930/j.issn.1004-9649.201912114

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The renewable energy in German has developed rapidly in recent years, and the penetration rate of renewable energy generation has increased year by year. This paper presents the energy transformation process in German over the past decade by analyzing various types of power supply installations, power generation, and power generation hours in German. At the same time, this paper carried on studies on the power consumption in German and the electricity exchanges with neighboring countries and electricity prices changing, and analyzed the impact of renewable energy development on German electricity prices. Finally, by analyzing the typical weekly power system operation data, response of German power system to the wind and PV power fluctuation is analyzed. German's renewable energy development and operation experience shows that the optimization of power system and maximization consumption of wind and PV power mainly depends on flexible spot market mechanism of electricity, strong power regulation capability and strong cross-national transmission network. And the development of wind and PV power will have a significant impact on the electricity production costs and electricity prices.

Quantitative Analysis of Return on Investment of Park Integrated Energy System for Multiple Investors

YAN Hu, HUANG Bibin, HONG Bowen, LI Qionghui, SUN Chongbo

2020, 53(5):  122-127,134.  DOI: 10.11930/j.issn.1004-9649.201811138

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Industrial parks have become important experimental areas for electricity reform in China. With the liberalization of incremental distribution market and widespread integration of diversified power sources and loads, the investment interface of park integrated energy system (IES) becomes divided, and the investment entities appear diversified. The analysis of investment benefits thus becomes more complex. This paper firstly analyzes the impact of electricity reform on the operation of park integrated energy system, and proposes four operating modes, including generation-distribution-sales integration, generation-sales integration, distribution-sales integration, and distribution network independent operation; Secondly, a quantitative return on investment model of park integrated energy system is presented for multiple investors, and a case study is conducted. Conclusions are given through a comparative analysis of the calculation results of multiple investors’ return on investment for the four operating modes.

Optimized Design of Lithium Battery System for Microgrid Energy Storage in Severely Cold and High Elevation Regions

ZHAO Bin, HU Ruwei, JIANG Dongfang, DONG Xiaodong, LUO Weilin, LIU Hui

2020, 53(5):  128-134.  DOI: 10.11930/j.issn.1004-9649.202001028

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Performance of lithium iron phosphate batteries was assessed, which were chosen for energy storage in the microgrid system in severely cold and high elevation regions. The influence of ambient temperature on those important parameters such as charge-discharge performance, cycle life, system capacity and safety performance was analyzed. The results showed that lithium iron phosphate batteries had long cycle life with excellent tolerability, especially at high charge-discharge rate. Meanwhile, such type of batteries also exhibited high durability and safety index. On the other hand, ambient temperatures had significant effect on the battery performance. For instance, the discharge capacity declined sharply at low temperature (-30 ℃), with only 89.89% relative capacity (compared to 25 ℃). Also the battery cycle life was shortened at high charge-discharge rate. Moreover, based on the climate conditions in the severely cold and high elevation regions, the lithium battery energy storage system was optimized respectively, and the reliability of system was experimentally verified in harsh environments. From the research results certain technical support can be provided for the application of lithium iron phosphate batteries in the severely cold and high elevation regions.

Application Prospect of Hydrogen Energy in Integrated Energy Systems

JIANG Dongfang, JIA Yuelong, LU Qiang, HONG Bowen, SHEN Ruibao, ZHANG Yan

2020, 53(5):  135-142.  DOI: 10.11930/j.issn.1004-9649.202003195

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The development and utilization of hydrogen energy is one of the most important ways to deal with global climate change, ensure national energy security, and achieve the low-carbon transition. The key parameters of hydrogen energy storage technology are compared with the current mainstream energy storage technologies. The results indicate the overall systemic advantage of hydrogen energy storage technology over others. The potential application of hydrogen energy in the integrated energy system and the future key technological breakthroughs are explored in the aspects of industrial users, transportation, combined heat and power in new construction, energy companies, and so on. In particular, this paper enlightens the roadmap of hydrogen energy development for China in the future. The results can provide references for the application of hydrogen energy in integrated energy systems.

Optimization of Reheat Steam Temperature Control for Ultra-Supercritical Units under Deep Peak Shaving

DING Jianliang, YU Guoqiang, LUO Jianyu

2020, 53(5):  143-149.  DOI: 10.11930/j.issn.1004-9649.201812016

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In view of the long time delay, large inertia and strong nonlinearity of the reheater outlet steam temperature in the process of deep peak shaving in thermal power plants, which makes the control less effective or hard to be put into service automatically, this paper proposes a humanoid intelligent control algorithm based on fuzzy switching. This method first optimizes the reheat steam temperature control system, and then uses the particle swarm optimization algorithm combined with the control experience to select the parameter settings. The simulation results show that the proposed method can enhance the robustness of the reheat steam temperature control system. In the actual operation of a 1 000 MW ultra-supercritical unit, satisfactory results have been achieved through this approach, which effectively improved the economic and security of the unit operation.

Application of Total Organic Carbon Measurements for Abnormal Water-Steam Quality Analysis in Thermal Power Plants

ZHANG Wenyao, TIAN Wentao, ZHI Qing, ZHANG Zhiyong, LIU Jiang

2020, 53(5):  150-154.  DOI: 10.11930/j.issn.1004-9649.201903058

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The total organic carbon(TOC) and total organic carbon ions (TOCi) of the water vapor in thermal power plants were measured and determined. Then through specific professional technical analysis, the causes of water vapor pollution can be quickly figured out. In this paper, the total organic carbon analysis technology is briefly described. Meanwhile, the water vapor pollution in three power plants is studied and the supervision of total organic carbon is suggested in response to the actual onsite situation. The results show that the abnormal increase of the hydrogen conductivity of the water vapor quality in the above three power plants is attributed to the demineralized water pollution, degradation of the cation resin and condensed water pollution respectively. Based on the analysis results, corresponding measures have been taken immediately at each power plant to resolve the problem.

Analysis on Design Scheme of Main-Auxiliary Combined Indirect Dry Air Cooling Tower for 660 MW Power Plant Units

LI Man, HAN Jingqin, LI Lujun, ZHAO Shun’an

2020, 53(5):  155-163.  DOI: 10.11930/j.issn.1004-9649.201908108

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In this paper, regarding the design scheme of the main-auxiliary combined cooling tower for 660 MW power plant units, a 3-D simulation model is built to study the impacts of ambient wind on the flow fields both inside and outside of the cooling tower. Also this paper explores how the variations of main and auxiliary circulating water temperature drop are affected by the ambient wind direction, the type of the heat exchanger of the auxiliary cooling unit and the method of increasing the number of cooling triangles. The results show that the ambient wind direction has very limited effects on the main circulating water temperature drop (about 1 ℃) but significant impacts on the auxiliary circulating water temperature drop (about 5.8 ℃). If the four-row-tube arrangement is adopted in the heat exchanger, the drop of the auxiliary circulating water temperature increases by about 0.2 ℃, and the drop of the main circulating water temperature decreases by about 0.06 ℃. The research results can provide reference for the engineering implementation of the design scheme of the main-auxiliary combined tower.

Time Series Forecasting of Partial Signals in Thermal Power Units

WANG Jiaxing, WANG Zhe, WANG Lin, AN Chaorong

2020, 53(5):  164-171,178.  DOI: 10.11930/j.issn.1004-9649.201908038

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Constrained by the performance of the equipment, certain issues have been existing in the main control parameters of boiler during the unit load changing process, such as large time delay and large inertia. As a result, it is not that straightforward to balance the contradiction between the needs of quick response to thermal load and stabilizing the main steam pressure. In the present work, a comprehensive method based on autoregressive moving average (ARMA) model and particle filtering is developed to perform time series forecasting on partial signals, which is designed to forecast the signals in advance such as main steam pressure such that the control delay of the main parameters could be alleviated to some extent on the boiler side. This method firstly establishes ARMA model based on historical data, then corrects the model parameters through particle filter algorithm, and at last applies the corrected model to forecast time series value. By using this method, the main steam pressure, total boiler coal quantity and main steam pressure setting value of the unit are forecasted and simulated on Matlab platform. The results show that the forecasting accuracy of this method is much better than that of ARMA model.

Study on the Control Strategy of Flue Gas in the Combined Cycle Power Station under Low Load Conditions

WANG Kai, LI Yugang, LIU Zhitan, WANG Bo, SHAO Weiwei, SUN Chen

2020, 53(5):  172-178.  DOI: 10.11930/j.issn.1004-9649.201811047

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The emission problem of yellow plume generally occurs at the combined cycle power plants where the heavy-duty gas turbines is installed and operated during the turbine start-up process or under low load conditions. It becomes even worse especially for those units actively participating the peak load regulation. It is found out that yellow plume is caused by the rising NO₂ concentration in flue gas. In order to further understand the formation mechanism of yellow plume in gas turbines for the purpose of more effective control on the content of NO₂ in flue gas under low load conditions, the authors took GE 6F.03 gas turbine as the research object and implemented the method of field flue gas testing by measuring the flue gas composition at different positions in the heat recovery steam generator (HRSG) at the start-up stage of gas turbine. Then the factors affecting yellow plume generation were analyzed and compared. Finally from the gas turbine side and the heat recovery steam generator (HRSG) side, the countermeasures and detailed control procedures for heavy gas turbine to suppress yellow plume are put forward.

Optimization of Chimney Height for Coal-Fired Power Plants for Ultra-Low Emission

MA Xueli, SUN Xijin, SU Shenshen, ZHANG Renfeng, DANG Lichen, HUANG Xianchang, XIE Yongping

2020, 53(5):  179-184.  DOI: 10.11930/j.issn.1004-9649.201903005

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Since the implementation of ultra-low emission in coal-fired power plants, the emission concentration and the ground concentration of gas pollutants have been reduced significantly. As a result, widespread concerns have been raised regarding whether it is still necessary to keep using high chimneys. The article studied the relationship between the chimney height and the maximum ground pollutant concentration of coal-fired power plant under ultra-low emission standards in plain areas. Particularly, the article investigated the building downwash under certain chimney height and explored the feasibility to optimize the height of the chimney. The results showed that since the implementation of ultra-low emission, the current recommended heights of chimneys for 300 MW, 600 MW and 1 000 MW generation units have decreased to 130 m, 140 m and 150 m respectively, while there is no significant increase of maximum ground pollutant concentration. Therefore, it is concluded that the magnitude of pollutant increase is acceptable without building downwash. Generally, the chimney height of coal-fired power plants under ultra-low emission in plain areas can be optimized and lowered further.