Table of Content

10 October 2016, Volume 49 Issue 10

Previous Issue    Next Issue

Genration Technology

Discussion on Waste Heat Utilization System of Coal-Fired Utility Boilers

LIU Yugang, , YI Guangzhou,

2016, 49(10):  1-6.  DOI: 10.11930/j.issn.1004-9649.2016.10.001.06

Asbtract ( )   PDF (1769KB) ( )  

References | Related Articles | Metrics

In recent years, it has been highly required for China's thermal power generation enterprises to reduce coal consumption rate to the stage with the accuracy up to milligrams. For the sake of improving the unit efficiency by deeply recovering the waste heat of boiler flue gas, the characteristics of four kinds of coal-fired boiler waste heat utilization system are introduced. Taking a 660-MW USC unit for example, the energy-saving effect of three waste heat utilization systems are analyzed by equivalent enthalpy drop method. The result shows that the cold air heater plus air heater flue gas bypass system has the best energy-saving effect with the coal consumption reduction of about 3.7 g/(kW·h).

Engineering Application of PIC System in Domestic Supercritical/Ultra Supercritical Thermal Generation Units

PENG Min, LIU Donglin, XIE Guohong, CHEN Jianqiang, LIU Fuping, CHEN Siming

2016, 49(10):  7-11.  DOI: 10.11930/j.issn.1004-9649.2016.10.007.05

Asbtract ( )   PDF (2099KB) ( )  

References | Related Articles | Metrics

“Thermal Power Unit Intelligent Control System” (PIC System) is a complicated system based on the unit auto startup and stop (APS) and the conventional intelligent control technologies. The engineering application of PIC system is hard due to the long application cycle, multiple stages, and the cooperation among different organizations and professions. In this paper, the key points of the engineering application of PIC system are analyzed and a complete set of engineering application methods are proposed which include the investment budget, the division of duties, the project scheduling and the implementation process. In addition, the application case of Guodian Hami 2×660 MW ultra supercritical units is introduced. This case is greatly helpful for the engineering application of PIC or APS system in various kinds of thermal power units.

Experimental Study and Numerical Simulation of K Type Thermocouple Dynamic Characteristics

GAO Ai’min, SHU Jianjun, YU Guoqiang, ZHANG Weiqing, XU Huaguan, XUE Rui

2016, 49(10):  12-16.  DOI: 10.11930/j.issn.1004-9649.2016.10.012.05

Asbtract ( )   PDF (5097KB) ( )  

References | Related Articles | Metrics

In this paper, the K type thermocouple is taken as the study object. A dynamic experimental system is designed and assembled using the temperature acquisition module and the calibration tester. With the system, the experiment on the dynamic characteristics of the thermocouple is conducted with the experimental data automatically acquired by Visual Basic and Utility software and visualised using Matlab. Based on the experiment, the maximum temperature increasing rates at different wire diameters, insertion depth and testing temperatures are evaluated. Meanwhile, the mathematic model of the thermocouple is set up with the visualization study of the experimental data by Matlab. The study results provide theoretical basis and application guidelines for the installation and maintenance of the thermocouple in thermal power plants.

Study on the Control Strategy of Double-Reheat Ultra-Supercritical Unit

YAO Jun, LI Lin, HOU Xinjian, ZHU Jianfei

2016, 49(10):  17-21.  DOI: 10.11930/j.issn.1004-9649.2016.10.017.05

Asbtract ( )   PDF (1987KB) ( )  

References | Related Articles | Metrics

Compared with single-reheat units, the thermal efficiency of ultra-supercritical (USC) units with double-reheat technology can be further improved, which results in primary energy saving, emission reduction and environmental protection. In recent years, with the development of design, manufacturing and operation technologies in USC, many countries including China have been encouraged to develop and construct double-reheat units due to the increasing demand for energy conservation and environmental protection as well as its advantages in cost effectiveness. In this paper, in combination with the double-reheat projects being built in China, the main difference of control strategy between double-reheat unit and single-reheat unit is introduced, and the functional design of reheat steam temperature control, coordination control, and bypass control in double-reheat units are explored.

Optimization of the Steam Temperature Control System Based on the Flow Characteristic Compensation of Desuperheating Water Regulating Valve

HUANG Weijian, LI Yibo, WAN Wenjun

2016, 49(10):  22-27.  DOI: 10.11930/j.issn.1004-9649.2016.10.022.06

Asbtract ( )   PDF (4601KB) ( )  

References | Related Articles | Metrics

The regulation quality of the steam temperature control system is of great importance to the safety and economical operation of thermal generation units. Particularly, the flow characteristics of the governing valve actuator directly affect the regulation quality of the control system. In this paper, through the analysis on the flow static characteristics of linear, equal percentage and parabolic valves and in combination with the tuning of the control system and parameters, it is concluded that the linear governing valve can maintain the regulation quality unchanged at different valve openings, which is good for the improvement of the control system stability. To improve the linearity degree of the governing valve in practical operation, the flow characteristic compensation principles and the calculation methods are put forward. Taking a 660-MW subcritical thermal generation unit for example, the flow characteristics of the A/B governing valves are calculated with the historic data of position and flow, and the flow compensation is applied in the steam temperature control loops. The unit operation result indicates that the regulation quality of the superheated temperature control loops is substantially improved. Finally, it is suggested that the flow characteristic compensation and correction of the valves should be taken regularly as part of the equipment maintenance.

Experimental Research on Thermal Performance of Large Seawater Cooling Tower Used in 1000-MW Power Unit

JIA Mingxiao, HU Sanji, FAN Zhijun, HAN Li

2016, 49(10):  28-32.  DOI: 10.11930/j.issn.1004-9649.2016.10.028.05

Asbtract ( )   PDF (1885KB) ( )  

References | Related Articles | Metrics

The thermal performance is the key affecting factor for the design of the cooling tower. In order to obtain the thermal performance of the large seawater cooling tower, the experimental research is conducted on the thermal performance of the large seawater cooling tower with 12 000-m2 drenching area used in a 1 000-MW power unit. From the research the thermal performance equation of the tower is obtained and the comparison is conducted between the tower’s thermal performance and the test results of the packing in the freshwater simulated cooling tower. The real air temperature distribution in the large seawater cooling tower is presented. The influence of seawater on the outlet water temperature of the cooling tower is analyzed quantitatively. The results can be a reference for the engineering application of the seawater cooling tower.

Application and Analysis of Key Technologies in Ultra-Efficient 1 000-MW Steam Turbine

LIN Xiuhua

2016, 49(10):  33-37.  DOI: 10.11930/j.issn.1004-9649.2016.10.033.05

Asbtract ( )   PDF (5117KB) ( )  

References | Related Articles | Metrics

There are two 1 000-MW units installed in the first phase project of Shenhua(Fuzhou) Luoyuan Bay Port & Power Co., Ltd. with the designed heat rate of 7 202 kJ/（kW·h）. In this paper, the steam turbines of this power plant are introduced and compared with the domestic 1 000-MW steam turbines of some other different types. In addition, the key technologies used in these steam turbines are analyzed, such as steam flow exciting vibration prevention and overspeed protection as well as the structure of HP/LP casing. The advantages of the ultra-efficient turbine are also expounded as far as the security and economic performance are concerned. At last, suggestions are put forward on future improvements in the aspects of shafting supports and heat regenerative system, etc.

Application of Shaft Dynamic Balancing Without Trial Weights to 1 000-MW Turbo-Generator Set

WANG Hao

2016, 49(10):  38-42.  DOI: 10.11930/j.issn.1004-9649.2016.10.038.05

Asbtract ( )   PDF (1899KB) ( )  

References | Related Articles | Metrics

In this paper, the principle of shaft balancing without trial weights is introduced., As the principle states, the type and the axial position of the shaft unbalance are judged accurately, then the focused measuring points are divided into several closely related combinations; based on the division, the effect of correction masses on the vibration of every combination is calculated with the influence coefficient. Then, the key points for practical application are explored, such as the accurate selection of the original vibration data and the influence coefficients, especially the precise control over the residual vibrations, to achieve overall optimal shafting vibration. At the end, this method is successfully applied to the field dynamic balancing of a DongFang 1 000-MW turbo-generator set, in which the abnormal vibrations are lowered to the excellent level by primary weighting, thus effectively reduces the startup times and costs for the power plant.

Research and Application of in-Depth Boiler Flue Gas Waste Heat Utilization and Emission Reduction Technology

CHANG Haiqing, ZHANG Yan

2016, 49(10):  43-48.  DOI: 10.11930/j.issn.1004-9649.2016.10.043.06

Asbtract ( )   PDF (6089KB) ( )  

References | Related Articles | Metrics

Having been put into use in a large domestic coal-fired power plant, through experimental studies this in-depth flue gas waste heat utilization system exhibits remarkable effects on energy saving and emission reduction. Under the 600-MW load conditions, the net standard coal consumption rate is decreased by 4.9 g/（kW·h）, and the dust emission concentration is lowered by 7.8 mg/m3 at the electrostatic precipitator outlet with the water consumption substantially being reduced in the wet flue gas desulfurization process. Moreover, the system operation is safe and reliable and the tuning procedures are quite flexible, which shows significant economic and environmental benefits.

Studies on Simulation and Performance of Different Gasification Technologies for the IGCC System

ZHAN Yang, , YOU Zheng, LU Junfu

2016, 49(10):  49-54.  DOI: 10.11930/j.issn.1004-9649.2016.10.049.06

Asbtract ( )   PDF (1939KB) ( )  

References | Related Articles | Metrics

In this paper, due to the convenience of the THERMOFLEX platform in thermal and IGCC power plant simulations, the models are built on the platform for several types of gasifiers including the Shell, Texaco, E-Gas and U-Gas ones. Based on the measured industrial data, the gasification conditions are set for simulation. Through the comparison between the composition of the synthetic gases and the industrial data, the simulation results of the gasifers are validated one by one. Then, the simulative study on six gasification technologies is carried out using the same designed coal. The study conducts the comparison of the main gasification indices between the technologies and analyzes their pros and cons when being applied in the IGCC system. The study results lay a foundation for the optimization of IGCC systems.

Power System

Performance Analysis of Single and Parallel ZnO Varistor Under Multiply Strokes

XIAO Yang, YANG Zhongjiang, LIU Jian, ZHANG Chunlong, LV Dongbo

2016, 49(10):  55-59.  DOI: 10.11930/j.issn.1004-9649.2016.10.055.05

Asbtract ( )   PDF (7437KB) ( )  

References | Related Articles | Metrics

8/20 μs multiply strokes are applied to ZnO varistors with 20 kA amplitude and 50 ms time interval. The experiments are performed on single ZnO varistor, parallel ZnO varistors with 10 V potential difference and parallel ZnO varistors with zero potential difference. The experimental results show that single ZnO varistor cannot bear huge energy of strokes. The bearing capacity of parallel varistors are doubled compare with single ones with same 40 kA waveform. However, with 10 V potential difference, the bearing capacity of parallel ones is even less than single configuration. By investigating electrical characteristic, temperature and feature variation of ZnO varistor under the multiply strokes, it is found that major damage mechanism of ZnO varistor is thermal breakdown.

Transient Temperature Calculation of Buried Cable Core Based on Parameter Fitting of Thermal Circuit

HUANG Xiongfeng, XU Binzhao, ZHANG Yujiao, CUI Houkun, WANG Tinghua, AN Zengjun

2016, 49(10):  60-66.  DOI: 10.11930/j.issn.1004-9649.2016.10.060.07

Asbtract ( )   PDF (8319KB) ( )  

References | Related Articles | Metrics

Transient temperature calculation of buried cable is of great importance in distribution capacity distribution and security warning. However, in practice thermal parameters of insulation material and surrounding soil are either difficult to obtain or subject to slow variations due to aging effects. Those lead to inaccurate cable temperature calculation results by means of numerical calculation or traditional equivalent thermal circuit. A thermal circuit based approach is proposed by fitting equivalent thermal circuit parameter with trust-region algorithm when the station and laying environment of the cable is known. A simplified formula is deduced to avoid parameter acquisition difficulty and reduce calculation complexity. The temperature-rise experiment data of a 110 kV cable proves validity of proposed method.

Influence of Ground Material on the Impulse Ground Impedance of Tower’s Grounding Devices

CAO Fangyuan, SHI Weidong, KANG Peng, ZHANG Bo

2016, 49(10):  67-73.  DOI: 10.11930/j.issn.1004-9649.2016.10.067.07

Asbtract ( )   PDF (13198KB) ( )  

References | Related Articles | Metrics

Grounding devices and soil resistivity affect the diffusion process when lightning current flows through grounding devices, and inherently affect the impulse grounding impedance of grounding devices. Based on the theory of electromagnetic fields and circuit method, this paper calculates the grounding impedance with different grounding materials, different lengths and diameters of grounding body, and different soil resistivity by using self-developed software. The time-domain voltage waveform is used to analyze the mechanism of the impulse grounding impedance influenced by above mentioned parameters. The analyzing results show that the magnetic permeability of grounding body has a great influence on the impulse grounding impedance. Under invariable cost of the grounding body, the longer grounding body of copper grounding device will lead the smaller impulse grounding impedance. Due to the limited effective length, the impulse grounding impedance reduction is not obvious with the increase of grounding body of steel grounding device. With the increase of soil resistivity, the impulse grounding impedance of copper grounding device increases linearly, but the impulse grounding impedance of steel grounding device is flattened out.

Improved Numbering Method Based on Breadth-First Search

LIU Aiguo, ZHANG Hong

2016, 49(10):  74-78.  DOI: 10.11930/j.issn.1004-9649.2016.10.074.05

Asbtract ( )   PDF (7269KB) ( )  

References | Related Articles | Metrics

In order to simplify numbering procedures and improve calculation speed on large-scale distribution network flow, an improved node numbering method is proposed based on breadth first search. With the proposed method, when adding new branch, numbers are added directly in parent node without need to consider branches of the same level network. Distribution network algebraic equations is used to calculate node voltage and power. VBA preprocessing and MATLAB simulation is performed on a 5-level open distribution network. The power flow results show the validity and practicability of proposed method. The calculation speed is faster than traditional method and satisfy the same accuracy requirement in distribution networks calculation.

Evaluation on Time-Domain Simulation Software Applied to Mid-and-Long Term Voltage Stability Study

CHEN Gang, FAN Chengwei, WU Wencheng, SUN Jingtao, HU Bowei

2016, 49(10):  79-83.  DOI: 10.11930/j.issn.1004-9649.2016.10.079.05

Asbtract ( )   PDF (6740KB) ( )  

References | Related Articles | Metrics

Mid-and-long term voltage collapse of large-scale power system is a slow process. The occurrence and changes are closely related to the dynamic behavior of slow components in system. Therefore, study on mid-and-long term voltage stabilities requires using simulation software that reflects slow dynamic process. Five simulation software packages, namely PSS/E, PSD-FDS, Eurostag, PSASP and DSATools are selected in this study. Practical analysis and evaluations are made to compare functions of these software packages in mid-and-long term time-domain simulations. Through simulation experiments, software parameters investigation and practical application examples, comparisons are performed on several aspects including principle and algorithm, simulation scale, components model and user interface. The results indicate that PSD-FDS provides better models and functions suitable for China power systems and precedes other software packages in mid-and-long term voltage stability research.

Optimization Research on Condition-Based Maintenance of Overhead Transmission Line with Online Detection Without Power Cut

WANG Feng, LEI Hongcai, PENG Xiang, CHEN Ping, ZENG Peng, HU Jun

2016, 49(10):  84-89.  DOI: 10.11930/j.issn.1004-9649.2016.10.084.06

Asbtract ( )   PDF (6897KB) ( )  

References | Related Articles | Metrics

The condition-based maintenance is the most prevalent maintenance mode at present. It is based on periodic evaluation of the equipment conditions. With the development of online detection, the traditional model of condition-based maintenance cannot meet requirement of developing grid. The sample database based on historical operation and maintenance data of transmission line is established first. The imminent, grave defects and faults in recent ten years are statistically analyzed. The detection efficiency of state variable and detecting mode is then studied. Combined with 74 critical state variable selected by expert, blind detection rate optimized evaluation of those critical state variable is performed. The feasibility of canceling transmission line routine test with power cut is discussed and the economic and safety issues are evaluated. The results show that current transmission line is capable of performing condition-based maintenance based on online detection without power cut.

Calculation of Reradation Interference in Ultra High Frequency from UHV Power Lines Based on IPO Method

TANG Bo, SUN Rui, ZHAO Xiaoming, JIANG Haotian, LIU Ren

2016, 49(10):  90-93.  DOI: 10.11930/j.issn.1004-9649.2016.10.090.04

Asbtract ( )   PDF (9539KB) ( )  

References | Related Articles | Metrics

The construction of UHV transmission line project is crucial for realization of long-distance power system interconnection. Study of VHF signals(30~300 MHz) passive interference adjacent to UHV transmission line is also very important. A passive jamming surface model of high voltage transmission line is proposed to use IPO(Iterative Physical Optics) method to solve VHF/UHV passive jamming problem. In VHF frequency band(30~300 MHz), discontinuities exist in UHV transmission line model are compensated by IPO method in order to solve passive jamming problem. The results show feasibility of proposed method.

Imperialistic Competition Algorithm for Unit Commitment Problem

ZHANG Ningyu, ZHOU Qian, WU Chong, HU Haoming, CHEN Jing

2016, 49(10):  94-100.  DOI: 10.11930/j.issn.1004-9649.2016.10.094.07

Asbtract ( )   PDF (7281KB) ( )  

References | Related Articles | Metrics

Based on human political and social process of evolution, an improved Imperialistic Competition Algorithm of intelligent methods for unit commitment is introduced in this paper. In ICA the initial population individuals(countries) are divided into two types: imperialists and colonies. The optimal solution is obtained by moving colonies toward their imperialists and imperialistic competition. Firstly, the daily load curve is divided into small time periods according to load peak and valley. Then unit ON/OFF variables are solved by ICA successfully. Compared with original algorithm, the proposed method avoids impact to optimal result by unreasonable units’ classification and shortens individual country coded length. Six test systems with 10~100 units are simulated by proposed algorithm. The results show that proposed method keeps excellent searching ability with less country and be able to obtain good solutions.

Treatment Decision-Making of Partition in Low Voltage Based on Spectral Clustering in Urban Power System

ZHANG Zhonghui, LIU Gushuai, XIE Yimiao, HE Lezhang

2016, 49(10):  101-105.  DOI: 10.11930/j.issn.1004-9649.2016.10.101.05

Asbtract ( )   PDF (7934KB) ( )  

References | Related Articles | Metrics

The governance decision making of low voltage in urban power system, while the distribution system is relatively lagging than transmission system in the power market environment, is in dire need of solving. The partition of governance is very important premise of governance decision-making of low voltage. A partition method based on spectral clustering algorithm is proposed. Firstly, sample space is established with consideration of minimum voltage amplitude, number of low voltage customer count, voltage over-limitation time and annual power supply. Secondly, Laplace matrix is built by Euclidean distance. The relative differences of eigenvalues of similarity matrix is selected automatically to determine partition number. The first two and three eigen vectors are mapped to 2d and 3d spaces which provide intuitive guidance for partition. Then evaluation function is constructed to evaluate partition effectiveness. When partition effect is acceptable, k-means algorithm is used to cluster feature vector, obtain partition spectrum diagram and structured partition scheme. The proposed algorithm is based on complex network theory and has rigorous theoretical basis. Finally, the effectiveness of proposed algorithm is verified by simulation results of a Power Grid of Jiangxi province.

Information and communications

High Performance and Scalability Power Communication Network Based on SDN

WANG Yirong, WANG Yanru, ZHANG Rongbo, WU Zhidong

2016, 49(10):  106-110.  DOI: 10.11930/j.issn.1004-9649.2016.10.106.05

Asbtract ( )   PDF (1952KB) ( )  

References | Related Articles | Metrics

Communication networks play a key role in power system development. Nowadays, power communication network adopts traditional“host-centric” networking architecture. This leads to high cost in investment, maintenance and operations which cannot meet increasing development and innovation needs of power system. Based on analysis of power communication network service, a novel power communication networks architecture based on software-defined network(SDN) concepts is proposed. Proposed framework can achieve high levels of networking performance, reliability and scalability. It is suitable for continuous evolution of innovating and management of networking at low-cost. It also has good scalability during development and deployment of new business applications.

Real-Time Communication Technology for UAV Transmission Line Patrol

WU Weinong, DU Haibo, YUAN Ye, BAI Hua, LIAO Yong, ZHAO Ming

2016, 49(10):  111-113.  DOI: 10.11930/j.issn.1004-9649.2016.10.111.03

Asbtract ( )   PDF (1471KB) ( )  

References | Related Articles | Metrics

UAV (Unmanned Aerial Vehicle) gathers large amount of information during transmission line inspection. The real-time communication poses high burden on wireless communication system. In order to improve application effect of UAV inspection, based on accurate analysis of transmission line construction characteristic, high gain directional antenna is introduced in the system. Transmission line section is covered by mutual coordination of beam with different width and angle. Beam switching technology is applied during signal processing to improve system ability. The power consumption, equipment volume and weight are reduced significantly during high speed transmission over long distance. Those techniques can continuously provide support for communication system high speed transmission.

Maturity Assessment of Power Information System Based on Big Data and Analytic Hierarchy Process

TAO Hongfei, SUN Yixin, WU Guowei, LI Kangyi

2016, 49(10):  114-118.  DOI: 10.11930/j.issn.1004-9649.2016.10.114.05

Asbtract ( )   PDF (1723KB) ( )  

References | Related Articles | Metrics

Based on big data theory and hierarchy analysis, a comprehensive maturity assessment method of operational system based on qualitative and quantitative analysis is proposed． Firstly, by data mining of massive application data, maturity evaluation index are extracted. Then, a hierarchical of structure maturity assessment system is built based on analytic hierarchy process. Finally, according to original score of each scheme indexes, sorting weight matrix of the solution layer and hierarchical ranking weight vector are constructed and integrated weight vector for maturity assessment are calculated． The validity of proposed method is verified by examples．

Impact of Reaction Conditions on Simultaneous Desulfurization and Denitrification Using Hexa-Amminecobalt Complexes

LIU Zhen, LI Qinghai, MA Zhixin, ZHANG Yanguo, TAN Zhongchao

2016, 49(10):  119-122.  DOI: 10.11930/j.issn.1004-9649.2016.10.119.04

Asbtract ( )   PDF (6654KB) ( )  

References | Related Articles | Metrics

By using cobalt ammonia complexing agent SO2 and NO can be removed simultaneously, which is of great significance for the emission control of coal power plants. Based on the analysis of the reaction mechanism of simultaneous desulfurization and denitrification with cobalt ammonia complexing agent, the experimental device is designed such that the major factors affecting [Co(NH3)6]Cl2 absorbent can be explored. The experimental results show that increasing the [Co(NH3)6]Cl2 concentration can improve the removal efficiency of SO2 and NO while extraordinarily high temperatures are disadvantageous to NO absorption. During the experiment, it is observed that the removal efficiency of NO reaches maximum at the temperature of 48 ℃. In addition, alkaline solutions can promote the oxidation of NO, while too strong alkaline solutions may cause instability of complexes and reduce the NO removal efficiency. Under the experimental conditions the best pH value of solution is 9.88.

Study on Testing Methods of Particulate Matter at Ultra-Low Concentration from Coal-Fired Power Plants

MENG Lingyuan, , ZHU Fahua, , YI Yuping, WANG Dongge, , ZHANG Xidan,

2016, 49(10):  123-126.  DOI: 10.11930/j.issn.1004-9649.2016.10.123.04

Asbtract ( )   PDF (6548KB) ( )  

References | Related Articles | Metrics

Since the ultra-low emission retrofitting in coal-fired power plants, the concentration of emitted pollutants has been reduced greatly, and the current particulate matter testing standards can no longer satisfy the monitoring requirements under the conditions of ultra-low emissions of particulate matter. It is necessary to set up new testing standards for particulate matters at ultra-low concentrations. In this paper, several particle testing methods commonly used domestically and abroad are summarized. Based on the comparative study and field tests, it is found that deficiencies exist in the domestic testing methods. Therefore, some suggestions are proposed to provide reference for establishing a standard testing method of particulate matter at ultra-low concentration from coal-fired power plants.

Performance Forecasting for SCR Honeycomb Catalyst Based on BP Neural Network

YANG Biyuan, ZHAO Jinxiao, WEI Hongge, WANG Yanpeng, ZHU Yue

2016, 49(10):  127-131.  DOI: 10.11930/j.issn.1004-9649.2016.10.127.05

Asbtract ( )   PDF (7186KB) ( )  

References | Related Articles | Metrics

Currently, the selective catalytic reduction (SCR) is one of the most widely used technologies for flue gas denitification. However, its De-NOx efficiency relies heavily on the catalyst. In this paper, take the example of a commercial SCR honeycomb monoliths, five sets of parameters, i.e., GHSV, temperature, oxygen content, NH3/NO ratio and initial NO concentration, are chosen in the De-NOx performance testing on a homegrown testing bed to study its effect on the De-NOx efficiency. Based on the testing data, the prediction model of De-NOx efficiency of SCR honeycomb monoliths is established by applying BP neural network. The results show that the convergence results are satisfactory when the topology structure is formulated as 5×7×1; When it is used in the performance forecasting, the absolute error is about 8% by average while the average relative error is 11% respectively, which proves the good fitting effect of BP neural network.

Current Operation State Analysis and Optimization Method Exploration on Double-Tower Double-Cycle Wet-FGD Systems

WEI Hongge, XU Minghua, CHAI Lei, ZHU Yue

2016, 49(10):  132-135.  DOI: 10.11930/j.issn.1004-9649.2016.10.132.04

Asbtract ( )   PDF (12786KB) ( )  

References | Related Articles | Metrics

Optimization and retrofit is needed for the FGD systems in order to meet the requirements of ultra-low emission. As one of the solution candidates, the double-tower double-cycle wet-FGD system is analyzed through field tests and investigations, in the aspects of desulfurizing efficiency, dust removing efficiency, system resistance and operation mode. The results show that the double-tower double-cycle wet-FGD system has the characteristics of high reliability and larger operating margin. Its desulfurizing efficiency can reach above 99%. Meanwhile, its collaborative dust removing effect is superior to single tower wet-FGD systems, which makes it an ideal choice for ultra-low emission retrofits in units burning middle-sulfur and high-sulfur coal. In addition, regarding the main problems of double-tower double-cycle wet-FGD system in its design and operation process, such as redundant reserved pumps, low utilization rate of oxidation fans in the secondary absorber, fast dropping speed and fast rising speed of liquid level in primary absorber and secondary absorber, high designed system resistance and so on, the corresponding optimization and improvement measures are proposed.

Estimation of Environmental Protection Space Based on PM2.5 Contributions for Guangdong Thermal Power Generation in 2020

QIN Yun, ZHENG Xiubo, ZHU Wenbo, LIN Yong, ZHENG Junyu, WANG Yanwei

2016, 49(10):  136-141.  DOI: 10.11930/j.issn.1004-9649.2016.10.136.06

Asbtract ( )   PDF (7147KB) ( )  

References | Related Articles | Metrics

Haze pollution caused by airborne fine particulates, typically PM2.5, has received lots of attention. In the Pearl River Delta area where the economy is growing very fast, the regional and complex air pollution characteristics are becoming increasingly evident. As the major emission source of electric power industry, the discharges from the thermal power plants have great impacts on the atmospheric environment. By analyzing the historic emission conditions and contributions of thermal power plants, under the constraints of the related policy control, the pollutant emission trends are predicted for not only thermal power plants but also the entire province of Guangdong in 2020. The contribution to fine particle pollution of thermal power plants is obtained by virtue of simulations based on CAMX (PSAT) model. Assuming that the contribution percentage is at the same level as that in 2012, and the average PM2.5 concentration complies to the national ambient air quality standard, the relationship between contribution percentage and generation capacity changes is established in consideration of the in-service and the planned power plant locations, thus the feasible installed capacity for new thermal power plant can be calculated for year 2020.

New Energy

Islanding Detection of Distributed Generation based on Wavelet Transform

JIANG Xiaoping, GE Chang, GUI Meng

2016, 49(10):  142-147.  DOI: 10.11930/j.issn.1004-9649.2016.10.142.06

Asbtract ( )   PDF (5994KB) ( )  

References | Related Articles | Metrics

To ensure the power supply quality for power customers and the safe operation of power systems, the distributed generation system is required to have islanding detection functions. In view of the shortcomings of conventional islanding detection methods for distributed generation systems, a new islanding detection method is proposed based on the wavelet transform. This method uses the wavelet transform to extract wavelet coefficient from the voltage of point of common coupling (pcc), and calculates the mean values of standard deviation and energy value of wavelet coefficient, and then determines the islanding through the preseted threshold value. It is proved through simulation that by overcoming the shortcomings of the conventional islanding detection methods, the proposed method can detect the occurrence of islanding quickly and accurately, and misoperation cannot happen even under various disturbances.

Methodology for Analyzing the Value of Energy Storage to Power System Frequency Control in Context of High Shares of Renewable Energy

WANG Caixia, LI Qionghui, LEI Xuejiao

2016, 49(10):  148-152.  DOI: 10.11930/j.issn.1004-9649.2016.10.148.05

Asbtract ( )   PDF (5486KB) ( )  

References | Related Articles | Metrics

Integration of large-scale renewable energy will bring a lot of challenges to power system planning and operation. Energy storage is one of the mitigation measures. This paper analyses the values of energy storage to power system frequency control in the context of high shares of renewable energy. Based on the value of energy storage in improving system frequency stability with disturbances and both primary and secondary frequency controls, the criterion for the needed storage are given and the methodology for calculating the energy and power capacity of storage are proposed. Energy strorage allocation is related to such factors as the shares of renewable energy, the moment of inertia provided by the conventional on-line power sources and the minimum transient frequency of power system. In view of the system’s oscillatory problems caused by high shares of renewable energy, the energy storage tracking system can be used to improve the performance of power system frequency control.

Methodology for Electric Vehicle Charging and Discharging Network Planning Based on a Dual Network Structure by Twice Partition

YANG Duo, SHEN Yongtao, DING Dong, WANG Yan

2016, 49(10):  153-158.  DOI: 10.11930/j.issn.1004-9649.2016.10.153.06

Asbtract ( )   PDF (9300KB) ( )  

References | Related Articles | Metrics

Based on the dual network structure, a secondary partition planning method is proposed for the electric vehicle charging and discharging network according to the grid operation and traffic situation. In view of the dual natures of the centralized battery charging stations, which is both the load of electric grid and the power supply for charging and discharging network, a dual network is established to connect the power network and the charging and discharging network. Preliminary partition is made according to the power service area and the load of the preliminary partition is predicted through traffic load gridding. Then, site selection is made for the centralized battery charging station according to voltage offset condition. Finally, secondary partition is made according to the traffic situation. The sites of discharging stations are chosen in the secondary partition by using the improved PSO algorithm. The rationality of this method has been proved through the charging and discharging network planning in one city.

Technology and Economics

Economic Benefit Evaluation Model of Distribution Network Planning Based on Multi-level Extension Evaluation Method

CHEN Yuan, WANG Lu, HUANG Youzhen, TANG Qinglan, XU Yuqin, HONG Qianli, ZHAO Beibei

2016, 49(10):  159-164.  DOI: 10.11930/j.issn.1004-9649.2016.10.159.06

Asbtract ( )   PDF (1420KB) ( )  

References | Related Articles | Metrics

Reasonable economic benefit evaluation of distribution network planning favors the scientific development of the distribution network, and realizing the maximization of power distribution network benefits. Based on the characteristics of distribution network, an economic benefit evaluation index system is developed for distribution network planning. From the respects of the run economic benefits, enterprise financial and social economic benefits, the Life Cycle Cost(LCC) theory is introduced to the analysis and calculation of enterprise financial performance evaluation indicators. Starting from the long-term economic benefits, the distribution network costs in various stages are fully consided. The Interval Analytic Hierarchy Process (IAHP) is applied to determine the comprehensive weight of each index, which effectively solves the complexity of the evaluation process and the uncertainty of influencing factors. The Matter-Element Extension theory is introduced to build the economic benefit evaluation model of distribution network planning based on Multi-Level Extension Evaluation method. Finally, the rationality and validity of the evaluation model is verified through a case study of a regional distribution network planning.

Seasonal Characteristics of Load Price Elasticity and Estimation of the Welfare Effects of Peak Price Policy

LIU Siqiang, YE Ze, YAO Jun, , LIU Yuzhe

2016, 49(10):  165-170.  DOI: 10.11930/j.issn.1004-9649.2016.10.165.06

Asbtract ( )   PDF (1383KB) ( )  

References | Related Articles | Metrics

The peak electricity price can drive customers to actively reduce the consumption of peak electricity load and voluntarily participate in demand response. Based on the secondary industry load data of Jiangsu province in latest three years, This paper studies the time characteristics of price elasticity of peak load with mathematical statistics method, presents the peak price policy benefit function, and analyzes the welfare effects of peak price policy in different degrees of demand response under different elasticity. The result suggests that the peak electricity price can remarkably increase the net social welfare, but the growth of different months and periods varies greatly. In accordance with the principle of social maximization, the policy and floating range of the peak electricity price should be determined by seasonal and time characteristics of load price elasticity.

A Comprehensive Evaluation Method for Urban Photovoltaic Power Generation Project Based on AHP-TOPSIS

CHENG Meng, ZHAO Shuangzhi, WU Lijie, HU Chuansheng, XU Hui

2016, 49(10):  171-175.  DOI: 10.11930/j.issn.1004-9649.2016.10.171.05

Asbtract ( )   PDF (1199KB) ( )  

References | Related Articles | Metrics

Reasonable allocation of urban photovoltaic power generation projects can bring substantial benefits to the existing urban distribution network. In view of the planning problem of photovoltaic power generation projects accessing to the urban distribution network, a systematic comprehensive evaluation method is proposed for photovoltaic power generation projects. From the perspective of photovoltaic investors and distribution network operators, a comprehensive evaluation indicator system with multi-layer characteristics is built, which considers the photovoltaic power generation cost, and the security, reliability and economics of distribution networks after integration of photovoltaic system. The proposed system can achieve a win-win situation for both photovoltaic investors and distribution network operators. In the end, the rationality and feasibility of the model and method are verified through a case study of the main feeder F4 of IEEE-RBTS BUS 6.

Research on Quota Estimate Model for Prototype Tower Test

GENG Pengyun, WANG Mianbin, AN Lei, QI Xia, YANG Yang, WANG Jianjun

2016, 49(10):  176-180.  DOI: 10.11930/j.issn.1004-9649.2016.10.176.05

Asbtract ( )   PDF (1299KB) ( )  

References | Related Articles | Metrics

Prototype tower test is a necessary link for power grid construction. At present, the charging standard of tower test is based on “Yuan/Ton” at large, which is not supported by any accurate references. In order to accurately determine the charging standard for prototype tower test and provide a basis for cost estimate and budgetary planning, the paper firstly clarifies the seven working procedures for prototype tower test, and then analyzes the influential factors of the charging standard for prototype test. Based on the collected real data, the costs for labour, material and machinery are determined with the statistical analysis method. A quota estimate model is established for prototype tower test of transmission lines based on the quota estimate theory and its rationality is tested through a case study.

The Comparison Between and Analysis on Technical and Economic Performances of Vertical and Horizontal Electric-Bag Precipitators for 300-MW Coal-Fired Power Plants

YOU Liangzhou, WANG Jianfeng, LI Zhuang, ZHU Yue

2016, 49(10):  181-184.  DOI: 10.11930/j.issn.1004-9649.2016.10.181.04

Asbtract ( )   PDF (2052KB) ( )  

References | Related Articles | Metrics

The electric-bag precipitator well combines the advantages of electro-static precipitators with those of bag precipitators and overcomes their drawbacks. In this paper, through the technical comparisons between the vertical and the horizontal electric-bag precipitators, it is concluded that the horizontal precipitator outperforms the vertical ones in terms of arrangement space, purge mode and bag damage risk; meanwhile, its retrofit cost is lower than that of the vertical ones under the same conditions.