Table of Content

18 December 2014, Volume 47 Issue 12

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Generation Technology

Discussion on the Roadmap of Power Generation Technologies using High-Moisture Indonesian Lignite

WANG Jun, YU Xue-hai, ZHOU Hong-bao, SONG Jian-jun, LIAO Hai-yan, HE Xiang-hui

2014, 47(12):  1-6.  DOI: 10.11930/j.issn.1004-9649.2014.12.1.5

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According to the characteristics of high-moisture lignite used in Guohua Indonesia Power Plant, three technical schemes are studied and compared, i.e., mid-speed coal mill with lignite drying technology, circulating fluidized bed boiler combustion technology and fan-type coal grinding machine system. Based on the operation conditions of domestic lignite-fired power plant, some advices on the technology roadmap are presented, which can provide a valuable reference for the selection of boilers using high-moisture lignite.

Experimental Study on Combustion Optimization for Ultra Low NO_x Emissions in 2 028 t/h Sub-Critical Boilers Firing Shenhua-Coal

HUANG Jun

2014, 47(12):  7-12.  DOI: 10.11930/j.issn.1004-9649.2014.12.7.5

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In order to figure out the mechanism of ultra-low NO_x combustion in deep staged air in the boilers firing Shenhua coal and achieve the integrative goals of anti slagging, high efficiency combustion and ultra-low NO_x emission, the directional adjustment test based on the multi-objective optimization technique is conducted. Through the optimization on the air distribution of the coal pulverizing system and auxiliary air system, the thermal efficiency is improved from 94% to 94.14%, the NO_x emissions at the entrance of SCR is reduced from 129 to 108.3 mg/m³, and the CO concentration of air pre-heater inlet also drops from 338 to 50 ppm with the unburned carbon contents both in fly ash and slag significantly decreased. The soot-blowing also is reduced from 3 times to 1 time one day, and the furnace cleanliness is enhanced significantly.

Cause Analysis and Prevention Plans on High Concentration NO_x Production at Low Load in Tangentially-Firing Utility Boilers

JIANG Hong-li, DING Hai-bo, WEI Tong-sheng

2014, 47(12):  13-16.  DOI: 10.11930/j.issn.1004-9649.2014.12.13.3

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The problem of high concentration NO_x produced at low loads is quite general in tangentially-firing boilers using high volatile coal. The theoretical analysis and field tests indicate that under medium and low loading conditions, as the air to fuel ratio richens in the initial firing stage the NO_x concentration increase substantially. Therefore, a new fuel air damper control scheme is proposed, in which the damper opening is adjusted at different loads. Consequently, NO_x production is significantly reduced at low loads with the boiler efficiency and steam temperatures hardly affected.

Study and Implementation of Comprehensive Thermal Protection Optimization in a Power Plant

GUI Yi-shu, SHEN Cong-qi, LYU Qiang

2014, 47(12):  17-20.  DOI: 10.11930/j.issn.1004-9649.2014.12.17.3

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Studies on the comprehensive optimization of thermal protection are of great significance for the safe and reliable operation of power plants. Through the overall analysis and studies on the protection system of Jiangsu Kanshan Power Plant, a comprehensive optimization plan is proposed. The plan includes using triple redundancy increasing, auxiliary judgment and related system reference (with the processing course in consideration) to implement system and auxiliary equipment protection control to ensure that the distributed control system(DCS) can not only operate correctly in case of equipment failure, but also determine the operating conditions of the major systems and auxiliary equipments precisely when the measuring points and auxiliary connections are abnormal. Since the plan is fully implemented, there has been no malfunction or failure of the thermal control system, which demonstrates that the correctness and reliability of the unit protection system are effectively improved.

Analysis on Early Stage Failure of Welded T23 Steel Waterwall in USC Tower Boilers

WANG Xue, LI Xi-qiang, YANG Chao, GE Zhao-xiang, YANG Xian-biao, REN Yao-yao

2014, 47(12):  21-27.  DOI: 10.11930/j.issn.1004-9649.2014.12.21.6

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The statistical analysis on causes of early stage failure of T23 steel waterwall in USC tower boilers is conducted. Macroscopic and microscopic examinations on the typical failured specimens are performed and the mechanical properties of the welded joints are tested to determine the mechanism and main factors for the failures. The results show that the failure are due to the traversing cracking occurred in the butt weld of pipes and propagated along its grain boundaries, which is regarded as wedge creep cracking. The high hardness of the weld is the internal cause for wedge creep cracking. The great tensile stress prodcued by the horizontal shrinking of dense fin welds in the waterwall, is the mechanical reason for the cracking formation and extension. Therefore, reducing the hardness and grain size of weld are helpful to aviod cracking.

Study and Application of LADRC for Drum Water-Level Cascade Three-Element Control

HU Chang-mei, REN Jun

2014, 47(12):  28-31.  DOI: 10.11930/j.issn.1004-9649.2014.12.28.3

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Based on the linear simplification of the ADRC controller, this study presents a method of tuning the relevant parameters in accordance with the request of the close-loop system’s response and applies the method in the drum-level cascade three-impulse control. The Matlab simulation results show that this linear ADRC(LADRC) requires less tuning parameters, and is simple to operate. It can meet the requirements of the steady-state response of the system, and has good robust for all kinds of interferences which makes it to stand out from the traditional ones. Therefore, the LADRC is an ideal choice for a large number of thermal-controlled objects with uncertain model in practice, and is good for promotion and application.

Design and Construction of Sacrificial Anode Cathodic Protection for Internal Surface of Buried Circulating Water Pipeline in a Thermal Power Plant

ZHANG Xiu-li, HUANG Zhi-juan, WANG Ying-gao, LI Yong-li, LI Qiang, LI Jun, ZHANG Shu-quan

2014, 47(12):  32-36.  DOI: 10.11930/j.issn.1004-9649.2014.12.32.4

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Taking the project of cathodic protection for the buried circulating water pipeline of Caoqiao Power Plant as a case, the principle of cathodic protection is briefly introduced and the design and construction method of sacrificial anode cathodic protection for the internal surface of the buried circulating water pipeline are presented, which include the design and construction approaches on the ventilation system required for the construction of the project. The implementation of the cathodic protection project shows that both the design and construction methods for the cathodic protection and ventilation are reasonable and effective.

Experimental Research on the PM_2.5 in Inlet and Outlet Flue Gas using ELPI for WESP of “Ultra-Clean Emission” Power Plants

LIU Han-xiao, ZHU Shao-ping, YAO Yu-ping, LI Jian-guo, CHEN Zhao-mei, CHEN Li, FANG Xiao-wei

2014, 47(12):  37-41.  DOI: 10.11930/j.issn.1004-9649.2014.12.37.4

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So far there is no corresponding standard released for measuring PM_2.5 in the flue gas from regular emission sources yet in our country. However, the testing technology for PM_2.5 emissions from coal-fired power plants still remains a hot topic in the current research. Especially it is difficult to perform the post-WESP PM_2.5 testing under low concentration and high humidity gas environment in current domestic engineering applications. In this paper, the testing study on PM_2.5 emissions from the WESP inlet and outlet of the first new “ultra-clean emission” coal-fired unit is conducted. By using high temperature dilute solution, the sampling gun and cyclone heat insulation, the influences of water droplets on the testing results are effectively avoided. Therefore, the results are of high credibility. The testing shows that PM_2.5 removal efficiency by WESP can reach as much as 78.77%.

Ultrasonic Inspection on Inner Surface Cracks of Small-Diameter Boiler Tube in Power Plant

YANG Jian-hua, MA Wen-min

2014, 47(12):  42-44.  DOI: 10.11930/j.issn.1004-9649.2014.12.42.2

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In order to prevent boiler tube explosion and leakage, it is necessary to detect the inner surface cracks of small-diameter boiler tubes using the ultrasonic. This paper introduces the ultrasonic inspection method focusing on the probe selection principles, making of the reference testing blocks, choosing of the sensitivity and scanning sensitivity and the examing standard setting. Taking the water wall tubes as an example, the determination of the false indication of inner tube surface threads and the wave characteristics of the inner surface cracks of small-diameter tubes are briefly described. Practice shows that the given method is helpful to improve the detection rate of the inner surface cracks of small-diameter boiler tubes.

Information Fusion Technology Based Feature Extraction Method for Ball Mill Load Measurement

WANG Jing-cheng, REN Zhi-wen, ZHOU Zhao-liang, SHU Jin

2014, 47(12):  45-48.  DOI: 10.11930/j.issn.1004-9649.2014.12.45.3

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The noise signals of ball mills contain important information on mill loads and are critical for mill condition determination However. because of the load sensitivity variety of their frequency spectrum,it is difficult to acquire the accurate and reliable information of load change. In this paper, a novel load feature extraction method is proposed. This method adopts the multi sensor consistency check algorithm to extract the mill noise characteristic frequency bandsthat are sensitive to the load response and obtain the mill load characteristic information by following the least square principle to fuse the scale value of characteristic frequency bands. The noise signals are gathered on site and used to take the simulation test on the new approach. The test results prove that the new method is effective and reliable.

R&D on the Simulator for Large “Two-Pull-One” Gas-Steam Combined Cycle Units

NIE Hai-long, ZHANG Wei, ZHOU Jian-zhang

2014, 47(12):  49-54.  DOI: 10.11930/j.issn.1004-9649.2014.12.49.5

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This article introduces the research and development and hardware configuration of the simulator for M701F “two-pull-one” gas-steam combined cycle units, expounds the technical features and software constitution of the simulation supporting system based on the general integrated CyberSim figure-mode-database simulation supporting platform and the mathematical models of the gas turbine. The complete working condition real-time simulation of the “two-pull-one” gas-steam combined cycle unit is realized with the simulation system. Test results show that theprecision of the gas turbine, heat recovery boiler, steam turbine and generator models meet the simulator design requirements and they have good static precision and dynamic response characteristics. The simulator can be used for the operation staff training and the analysis & research of power plant control strategic optimization and operation mode.

Power System

Field Full-scale Tests on Group Anchorage Rock Foundations of DC UHV Transmission Line Project

CHENG Yong-feng, ZHAO Jiang-tao, LU Xian-long, ZHANG Yan, LI Wei, HOU Peng-xiang, HUANG Xin-huai

2014, 47(12):  55-60.  DOI: 10.11930/j.issn.1004-9649.2014.12.55.5

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A new type of group anchorage rock foundation is presented according to the fact that the load of UHV DC transmission tower foundations are large and the scheme of unequal tower leg length with unequal height of foundation is widely used in the UHV DC transmission project. In addition, three uplift load tests were carried out on 2×2 bearing platforms with four bolts of different anchor length and rock-socked depth, and three load tests were also carried out on 3×3 bearing platforms with eight bolts of different anchor length and rock-socked depth under uplift combined with lateral loading. It is indicated that the lateral loading could reduce the uplift capacity of the group anchorage rock foundation obviously. Increseaing the bolt anchorage length or the rock-socked depth can effectively enhance the uplift and lateral bearing capacties of the group anchorage rock foundation.

Analysis of Electric Power Load Characteristics and Its Influencing Factors in Chongqing Region

LEI Shao-lan, GU Liang, YANG Jia, LIU Xin-yu

2014, 47(12):  61-65.  DOI: 10.11930/j.issn.1004-9649.2014.12.61.4

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It is very important to study the load variation characteristics for improving the short-term load forecasting accuracy. The variation characteristics of the annual maximum load, annual minimum load and typical daily load is analyzed in this paper based on the recent historical load data and meteorological data of Chongqing region. Besides, the interrelationship between the load characteristics and the major influencing factors is studied, and the influencing extent of the major factors on the region’s load and the main influencing time period are analyzed according to Chongqing’s geographic characteristics. The results show that the temperature, rainfall, holidays and festivals have a significant influence on the Chongqing region’s power load at present, which can provide a theoretical basis for studying the short-term load forecasting method and analyzing the smart grid load characteristics.

Research on RTDS-based Modeling and Simulation Testing of Guizhou Power Grid

XU Mei-mei, JIA Xu-dong, LI Wei, ZHAO Wei-xing, GU Wei, ZHANG Fang

2014, 47(12):  66-71.  DOI: 10.11930/j.issn.1004-9649.2014.12.66.5

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In order to test the function and performance of wide-area PSS controller, the RTDS model of Guizhou Power Grid is set up according to the peak load scenario. Steady power flow and fault transient process with the RTDS and BPA equivalent system are simulated and compared, and it is proved that the RTDS model can meet the relevant requirements of real-time simulation and equipment performance testing. A closed-loop test system is constituted with other external devices. A simulation testing is conducted on the basic control functions of the wide-area PSS, and it is verified that the wide-area PSS can further increase the system damping in operation of the generator PSS, effectively suppress the inter-grid oscillation, and provide a strong technical support for the pratical application of this control system.

Application of Improved Analytical Hierarchy Process in Comprehensive Assessment of the Power Quality With Distributed Generators

ZHAO Xian, ZHOU Li-xing, DENG Wei

2014, 47(12):  72-78.  DOI: 10.11930/j.issn.1004-9649.2014.12.72.6

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Considering the complicated and nonlinear characteristics of power quality indices, an improved analytical hierarchy method is introduced in this paper for power quality assessment of distributed generator system. The method uses the three-demarcation to improve the traditional unanimous decision, and, as a result, the difference of each index become clearer and the result is more accurate. Firstly a power quality assessment hierarchy model is established from six dimensions including frequency bias, voltage deviation, voltage fluctuation, voltage surge, voltage harmonic and three-phase voltage unbalance factor. Secondly, each power quality index is quantified through expert decision, and the weight to the power quality of above six indices obtained with the improved analytical hierarchy method, The power quality from each substation bus is graded through processing the original monitoring data and with combination of the weight value. Finally, the overall assessment of power quality is given. Compared with other methods, the improved analytical hierarchy method is proved to be feasible and effective. The calculated result of the proposed method can provide a reference for the technicians.

Investigation and Treatment of Metal Passivators in Mineral Insulating Oils of Transformers in Guangdong Power Grid

ZHANG Li, QIAN Yi-Hua, SU Wei

2014, 47(12):  79-82.  DOI: 10.11930/j.issn.1004-9649.2014.12.79.3

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The metal passivators added in the transformer insulation oil can effectively relieve the corrosion caused by corrosive sulfur. In order to fully understand the changes of the metal passivator content in the mineral insulating oils of transformers in Guangdong power grid, the content of metal passivators in 208 transformers was traced quantitatively by virtue of the High Performance Liquid Chromatographic (HPLC) method. The census results show that the metal passivator content in 60 transformers decreases substantially. In particular, 19 of them exhibit significant changes. Based on the relevant international standard, the operational supervision treatment of the transformer insulating oil with metal passivator additive is proposed. The census results can provide references for the establishment of standards on metal passivator additions and corresponding operations in our country.

Research on the Energy Capacity Evaluation Method Based on SiC De-excitation Resistance Off-Line Testing

WU Kua-yu, LU Jia-hua, LU Cen-cen, XIONG Hong-tao, ZHAO Yi-yan

2014, 47(12):  83-87.  DOI: 10.11930/j.issn.1004-9649.2014.12.83.4

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In order to improve the evaluation accuracy of the SiC de-excitation resistance energy capacity, the testing data of macro-energy injection, infrared imaging and average energy of multiple components are analyzed based on a novel off-line testing system of SiC de-excitation resistance and its relevant testing items. A new parameter“heat dissipation reciprocal coefficient” is defined to revise the impacts of unpredictable physical processes such as heat dissipation and equalization on the calculating results. A set of methods are proposed for comprehensive evaluation of the SiC de-excitation resistance energy capacity based on the off-line testing data and with a reference to the manufacturer’s design parameters. Finally, the influencing factors of the proposed evaluation method are analyzed and corresponding measures are proposed.

Application of S-Shaped Droop Control Method in Peer To Peer Control of Microgrids

LI Jun, YANG Zhi-chao, CHEN Fan

2014, 47(12):  88-94.  DOI: 10.11930/j.issn.1004-9649.2014.12.88.6

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Application of inverter droop control strategy is vital for micro-grids to maintain the“plug and play” characteristics. While the conventional droop technology in inverters usually results in large frequency deviations in dealing with large incremental load demand, even breaking the upper and lower frequency limits, the ability of automatic share of load demand among sources is attractive. Based on secondary frequency regulation trajectory of synchronous generators, the S-shaped droop characteristic curve is designed and the mathematical model is built. And then the S-shaped control compatibility with conventional droop control is analyzed. With the help of Matlab/Simulink tools, the simulation results demonstrate that the S-shaped droop control can effectively improve the defect of inherent frequency deviation. The inverter controlled by S-shaped droop can operate with the inverter controlled by conventional droop independently with the ability of automatic sharing load demand among sources.

New Energy

Coordinated Charge and Discharge Control Strategy Based on Time-of-use Price from Electric Vehicle Customer Side

YU Hao-ming, HUANG Chun, ZHAO Wei

2014, 47(12):  95-98.  DOI: 10.11930/j.issn.1004-9649.2014.12.95.3

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With the large-scale development of electric vehicles, EV users prefer to take a quick and easy way of personal charging in the future. Based on this trend, a coordinated charging and discharging control strategy is proposed in this paper. According to the constraints of charge-discharge power and the electricity price of charging and discharging provided by the superior system, a coordinated charging and discharging model is proposed to minimize the fee of the total expenditure for EV users by introducing incentive factor and optimizing the charging and discharging power each time. In case studies, the economical charge-discharge solution is provided for EV users by applying the simplex method to obtain the optimal solution.

Study on Transient Stability of VSC-HVDC-Based Wind Farm

WU Han, WANG Wei-qing, WANG Hai-yun, RAO Cheng-cheng

2014, 47(12):  99-104.  DOI: 10.11930/j.issn.1004-9649.2014.12.99.5

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Two integration modes including voltage source converters(VSC-HVDC) and AC transmission(HVAC) are studied for wind farms. Based on the VSC-HVDC dynamic model which is built in dq synchronous frame, a control strategy is designed for the converter stations on both ends. Two wind farm integration models (AC and DC) are built in DIgsilent/Power Factory and the conditions of the AC bus short-circuit fault at the receiving converter station are simulated and verified by the models. Based on the simulation, the local load power, bus voltage, output power and the speed of generators of the wind power system are then studied. The results demonstrate that the VSC-HVDC can improve voltage, reduce the oscillation of active power and avoid over-speeding during system fault. The control strategies are proved to be feasible.

Application of PV Generation in 500 kV Substation and Its Impact Analysis

SHI Shi-hong, GUO Fang

2014, 47(12):  105-109.  DOI: 10.11930/j.issn.1004-9649.2014.12.105.4

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In power grid, substations are numerous and have large potential capacity for PV power generation, it is therefore necessary to analyze the application of PV power generation in substation and its impact on substation. Based on a 500 kV substation, the power of PV generation and the load capacity of substation are calculated and the electrical connections of PV generation are discussed. A Matlab simulation model is established based on the actual parameters of a 500 kV substation which embeds PV power generation, and a simulation analysis is carried out on the impacts of PV generation on the power quality and voltage quality of substations.

Development and On-Line Application of the Reactive Power Regulation Analysis System of Jibei Wind Farms

ZHAN Qing-cai, LIU Hai-tao, WANG Ying, CHEN Cheng, ZHENG Ji-hu

2014, 47(12):  110-116.  DOI: 10.11930/j.issn.1004-9649.2014.12.110.6

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The paper introduces the development and on-line application of the automatic analysis system for reactive power regulation of JiBei Power Grid Wind Farms. By using the Jibei smart grid dispatching technical support system as its platform, the automatic analysis system can perform on-line reading of the WAMS dynamic data in the Jibei Electric Power Dispatching Center and carry out one-line assessment and analysis of relevant indicators. An index system is built for evaluating the reactive power regulating ability of wind farms. The main function modules of the system and the implementing scheme are also introduced. The actual results from system operation proves that all analyzing and computing modules have good operational robustness, and can carry out auto-analysis and assessment of the online reactive power regulating ability for the continuously varied real-time operation data of wind farms. The system is promised to have good application value.

Information and Communication

Channel Estimation and Symbol Detection for Spread OFDM System

LI Bing

2014, 47(12):  117-120.  DOI: 10.11930/j.issn.1004-9649.2014.12.117.3

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Frequency diversity can be exploited for performance improvement of symbol detection. However, there is no frequency diversity gain in traditional OFDM system. Therefore, a block spread OFDM system was designed for the frequency selective fading channel, in which a spread transform on the information block was performed at the transmitter. Moreover, a least squares (LS) based channel estimation and minimum mean squares error(MMSE) based symbol detection scheme were proposed for the receiver. Simulation results corroborate the validity of the channel estimation and symbol detection scheme, and the symbol detection performance is effectively improved by the spread transform.

Multipoint Temperature Monitoring of High Voltage Switchgear Based on Wireless Sensor Network

XU Gao-jun, MA Hong-zhong, LI Chao-qun, LI Kai, XU Hong-hua

2014, 47(12):  121-126.  DOI: 10.11930/j.issn.1004-9649.2014.12.121.5

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The necessity of online temperature monitoring of high voltage switchgear are analyzed in this paper, and a comparison is made of the existing temperature measurement methods. Basing on the theory of wireless sensor network and point-to-multipoint communication system, a design scheme of a point-to-multipoint monitoring system for high voltage switchgear is introduced based on the wireless temperature sensor network, including the hardware selection and the design of software and two-way communication protocol. This system has many strong advantages, including low cost, simple structure, convenient installation, low power consumption, simple communication protocol, good stability of data communication, and intuitive interface for the monitoring display. Consequently, it can be used for multi-point temperature measurement of high voltage switchgear in substations.

Technology and Economics

Life Cycle Cost Risk Assessment of Power Transformer Based on Matter-Element Model

XU Yu-qin, REN Zheng, ZHAN Xiang-ling, LI Tong, HU Wei-tao, QIAO Guo-hua, XIE Qing

2014, 47(12):  127-132.  DOI: 10.11930/j.issn.1004-9649.2014.12.127.5

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Assessment of risk factors in power transformer life cycle cost modeling is important for improving the efficiency of transformer life cycle cost management. According to the risk factors in transformer life cycle cost, a risk assessment index system of transformer life cycle cost is established, and a matter-element model for transformer life cycle cost risk assessment is proposed by introducing the matter-element model and extension analysis theory to quantify the qualitative indexes. Through case study, the uncertain factors in power transformer life cycle cost management are quantified and a life cycle cost risk assessment system is established. The matter-element model is used to evaluate the risk rating of the transformer cost, and the key risk factors in transformer cost are obtained. In practice, some control strategies can be proposed for various risk factors.

Pricing and Benefit Estimation Method for Trans-province Transmission Based on Power Flow Tracing

GAO Xiao, ZHENG Hou-qing

2014, 47(12):  133-136.  DOI: 10.11930/j.issn.1004-9649.2014.12.133.3

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It is very important to establish a fair and reasonable pricing and benefit estimation method for trans-province transmission, which can provide the information of price and economic signals for both sides of the traders. Based on the improved power flow tracing, a pricing model is established for trans-province transmission, which can make the load not undertake the transmission cost for the branch initiated from that load node. Then a consumer surplus calculation model is built by using the up-stream tracing method to define the feeding power source corresponding to the load,and the benefit of trans-province transmission is evaluated accurately, in which the influence of each trader’s topology on the physical flow is fully considered.

Energy Conservation and Environmental Protection

Quantitative Research on the Ground Audible Noise Influenced by ±800 kV UHVDC Transmission Lines’ Structure Parameters

ZHANG Qiang, LIU Yuan-qing, LU Bin-xian

2014, 47(12):  137-143.  DOI: 10.11930/j.issn.1004-9649.2014.12.137.6

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For UHVDC projects, the audible noise level is a basic indicator for electromagnetic environment assessment. Five different audible noise prediction formulas used in the DC transmission lines were introduced in this paper, By comparing the measured noise data of the Xiang Jiaba-ShangHai ±800 kV transmission project with the calculated results, it was concluded that the EPRI formula is better suitable for predicting the audible noise of UHVDC transmission lines in our country. Based on this formula, the impacts of different conductor structures on the audible noise were analyzed, and it was found that the conductor’s bundle number is the key factor that impacts the audible noise. With the voltage keeping at ±800 kV, the audible noise at the reference point decreases by 10 dB(A) when the bundle number increases by 2 from 4 to 8; With the surface electric field keeping constant, the audible noise increases by 2 dB (A) when the bundle number increases by every 2.

Performance Testing of Plate SCR Catalysts

MENG Xiao-ran, YU Yan-ke, CHEN Jin-sheng, WANG Jin-xiu, CHEN Yan-ting

2014, 47(12):  144-148.  DOI: 10.11930/j.issn.1004-9649.2014.12.144.4

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The mechanical performance, micro characteristics and technical activity of three commercial plate SCR catalysts are evaluated systematically according to the requirements in the Testing Guideline of SCR Catalysts for Thermal Power Plant(DL/T 1286-2013). The evaluation results show that all three catalysts have good mechanical performance with high abrasion resistance and adhesion strength. The BET surface area of the catalysts is quite large, ranging from 70 m²/g to 100 m²/g. In the technical activity analysis these catalysts exhibit high activity and low SO₂/SO₃ conversion rate which is less than 1%. The methods adopted and the results obtained in this paper can provide references for the performance evaluation of plate catalysts.

Life-Cycle Environmental Impact Assessment of a Typical 2×200 MW Natural Gas Combined Cycle-Combined Heat and Power Plant

SONG Guo-hui, TANG Lu, JIANG Wu, XIAO Jun

2014, 47(12):  149-155.  DOI: 10.11930/j.issn.1004-9649.2014.12.149.6

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Jiangsu Province has witnessed vigorous development of natural gas combined cycle(NGCC)-combined heat and power (CHP) plant in recent years. In 2012, the utilization of natural gas in Jiangsu Province ranked first in China. The life cycle assessment of a typical 2×200 MW natural gas combined cycle-combined heat and power plant is proposed in this paper. The life cycle assessment(LCA) results indicate that the indicators, such as Chinese abiotic depletion potential (CADP), global warning potential (GWP) and acidification potential (AP), are important environmental impact categories in this type of co-generation plant. In contrast, the indicator of respiratory inorganics (RI) is minor. Plant operation contributes to all environmental impact categories, especially CADP and GWP. Natural gas exploitation and pipeline transportation only markedly contribute to AP and RI. Finally, construction & decommissioning contributes less to all the indicators. Compared with coal-fired power, natural gas has greater advantages in terms of environmental impacts. Compared with coal-fired power, the GWP, AP and RI of natural gas-fired power account for 20%, 15% and 5% of those of coal-fired power, respectively. However, due to the scarcity of natural gas resources, the CADP of natural gas-fired power is 3~3.5 times of that of coal-based power.

Experimental Research on Simultaneous Desulfurization and Denitrification by O₃/NaClO Gas-Liquid Phase Oxidation

LI Juan-juan, JIANG Bin, JIANG Yan-yan, PAN Li-li

2014, 47(12):  156-160.  DOI: 10.11930/j.issn.1004-9649.2014.12.156.4

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In this paper, a new method of simultaneous desulfurization and denitrification by O₃/NaClO composite sorbent for thermal power plants is proposed. Its efficiencies of desulfurization and denitrification are also tested under different conditions. Considering the actual operation conditions, the initial concentration of SO₂ and NO_x are set as 600 mg/m³ and 500 mg/m³, respectively. The results indicate that the efficiencies of desulfurization and denitration reach as much as 97.04% and 95.08% respectively under the following conditions: ozone dosage, 5.35 g/h; NaClO concentration, 15 mmol/L; absorption solution initial pH value, 5; ratio of liquid to gas, 50 L/m³; and reaction temperature, 50 ℃. Additionally, this method has the advantages of simple operation procedures and fast SO₂ and NO_x removal without any clogging or scaling issues. If the production cost of O₃ can be reduced effectively, it is certain that this new method will have a very promising industrial application prospect.