Table of Content

18 April 2012, Volume 45 Issue 4

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Power System

Power system stability analysis and measures of the Xinjiang grid after Xinjiang-Northwest power grid interconnection

ZHANG Yu-qiong, WANG Xin-bao, CHENG Lin, CHANG Xi-qiang, SUN Yi-qian

2012, 45(4):  1-4.  DOI: 10.11930/j.issn.1004-9649.2012.4.1.3

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Power system transit stability analysis is performed in two typical operation modes of Xinjiang power grid before and after interconnection with Northwest grid by using PSASP simulation package. The simulation results show the change of stability characteristics after interconnection. The interconnection improves power angle, frequency and voltage stability but reduces thermal stability. Technical measures are investigated and proposed to guarantee power grid operation safety and stability.

Research on power grid stability control strategies for Ningdong DC line on Shandong side

ZHAO Qiang, XU Jing, WANG Qi, WANG Jian-Ming, ZHANG Wen-Chao, LI Yi-Qun, LI Xin, XU Yuan, HOU Yu-Qiang, YU Yang

2012, 45(4):  5-5.  DOI: 10.11930/j.issn.1004-9649.2012.4.5.0

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In order to study the influence of Ningdong DC bipolar fault on the synchronized security and stability of North-Central China power grid, the coupling between Ningdong ±660 kV DC project and UHV tie-line transmission power was analyzed based on the theoretical analysis of UHV AC pilot project steady stability limit. The influence of DC bipolar locking on the peak flow of UHV tie-line was investigated. According to the practical case study, load model of Shandong Grid was identified as an important factor in computation. The stability control measures and deployment scheme for Shandong grid after the operation of Ningdong DC project were proposed and tested by simulation. HVDC modulation is selected as the method to enhance stability in North-East Grid. The research result can be used as reference for future implementation of stability control system for interregional interconnection power system.

Research on demand response for wind power integration into smart grid

LIU Xin-dong, CHEN Huan-yuan, FANG Ke

2012, 45(4):  10-14.  DOI: 10.11930/j.issn.1004-9649.2012.4.10.4

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A multiple-objective optimization method was presented to improve the ability of wind power integration of a grid by using the demand response. The method divides the demand response into interruptible load and consumption stimulation load; and then defines their influences to the probability density function of the equivalent load. Based on the quantitative relationship among demand response, system revenue and peak-regulation capacity, an optimal objective function for revenue and capacity was proposed. A fuzzy method was deployed to solve the optimization problem. Taking the equivalent load of the grid of Shaan-gan-ning-qing in Northwest China as an example, the test results show that the demand response can improve peak-regulating ability of the grid with widely distributed wind power generation and increase economic efficiency. This study can provide effective supporting information for dispatchers to do decision-makings.

Voltage influence of wind power integration

LI Qiang¹, LI Feng-ting¹, FAN Yan-fang¹, CHANG Xi-qiang², SU Chang-sheng³

2012, 45(4):  15-18.  DOI: 10.11930/j.issn.1004-9649.2012.4.15.3

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Large scale wind power integration has influnece on local grid voltage. With the scale increase of the wind power capacity, the analysis of voltage influence with wind power integration becomes very important. Taking wind power integration in Hami area in Xinjiang as example, the bus voltage level in typical operating modes after wind power integration is analyzed in detail. The wind turbine simulation model is established with consideration of wind speed under wake effect. The voltages on key nodes are analyzed with real time power flow results. Two methods, namely reactor and SVC compensation, are discussed and simulated in order to improve voltage quality with wind power integration.

Optimization design of 220 kV switchyard and transformers arrangement in thermal power plant

CHEN Hai-hua

2012, 45(4):  19-22.  DOI: 10.11930/j.issn.1004-9649.2012.4.19.3

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After in-depth analysis of field situation, an optimal power plant switchyard scheme design with high technical reliability and economic benefits is presented. A 220 kV substation in thermal power plant adopted the layout design to combine the areas of both switchyard and transformers outside of column A of gas turbine house instead of the traditional design to separate them into two exclusive areas. The new design optimizes general layout, improves space utilization rate, and clarifies the boundary among functional areas. It also improves device reliability and operation security, reduces operation and maintenance work load, and facilitates equipment installation and maintenance process. The environment friendly design also satisfies long-term expansion needs.

Comprehensive decision making of distribution network planning based on group AHP

YI Yu, WEI Gang, YANG Jia-jun, HU Yin

2012, 45(4):  23-28.  DOI: 10.11930/j.issn.1004-9649.2012.4.23.5

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The process of comprehensive decision making of distribution network planning is inevitably affected by subjective consciousness, which would reduce the reliability of decision. So minimizing the impact of subjective deviation on decision making as much as possible is important to reasonable grid construction and reformation. In this paper, group decision making based on AHP （GAHP） is introduced, which can realize consistency analysis of each decision group members' opinion and work out the dynamic weight of each members, and then form an objective, representative aggregation opinion. It provides a new method for the final program sorting. GAHP could enhance the objectivity and fairness as well as improve the accuracy and reliability of the results of decision making. The example shows the correctness and simplicity of the proposed GAHP.

The experimental study and application of PPG pile in transmission line

JIANG Hong-xi¹，LIN Qing-hai¹，CHEN Pei²，CAO Dan-jing¹， JIN Shu¹，SUN Zong-de¹，XIE Guang-cai¹

2012, 45(4):  29-34.  DOI: 10.11930/j.issn.1004-9649.2012.4.29.5

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Recommended as a new type of pile foundation by building specification published in 2008, pile post grounding (PPG) pile has characteristics of high reliability, large bearing capacity increase and economic efficiency. However, it is not used widely in transmission line building due to lack of related parameters. The PPG pile field pulling and horizontal bearing test were described in detail in order to get calculation formula and parameters. Experimental data show that PPG pile can improve bearing capacity by 30%~50% and reduce construction cost by 15%~35% compared with common pile under condition mainly dominated by uplift force. Parameters under various conditions, including bearing pressure, uplift and horizontal affect, are recommended to facilitate later project application.

Application prospect of large cross-section conductor on UHVDC transmission line

ZHOU Kui, CHEN Yuan, LIU Li-lin, XU Wei-yi

2012, 45(4):  35-37.  DOI: 10.11930/j.issn.1004-9649.2012.4.35.2

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At present, the largest conductor applied on ±800 kV UHVDC transmission line is 6×900 mm² ACSR. Base on analysis of preliminary stage investment and power loss, a life cycle economic comparison on 6×JL/G2A-900/75, 6×JL/G2A-1000/80, 6×JL/G2A-1120/90 conductor types is performed. It is verified that application of 6×JL/G2A-1000/80 and 6×JL/G2A-1120/90 conductor types in 800 kV UHVDC transmission lines has economic advantages when the number of annual power loss hours is relatively high.

Testing analysis of dielectric loss and capacitance of ultra-high voltage capacitive voltage transformer

SU Chen-yun, HUANG Zhen

2012, 45(4):  38-41.  DOI: 10.11930/j.issn.1004-9649.2012.4.38.3

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The measuring of dielectric loss and capacitance of capacitive voltage transformer is important for equipment insulation level. The test on ultra-high voltage 1 000 kV capacitive voltage transformer is different than other transformers. The method to measure two different structural 500 kV CVT is systematically introduced. Furthermore, a new test method of 1 000 kV CVT is proposed according to particular feature of 1 000 kV CVT. The method use external standard capacitor, internal high voltage and positive connection to measure C2 capacitor of CVT. The test results meet standards of UHV AC pilot project hand-over regulations according to the on-site test, which proves the validity of proposed method.

Research on potential distribution in transformer with subsection and layer windings under VFTO

DOU Yu-lei, JIANG Zhong-jie, WANG Ya-jun, XUE Zhi-ying

2012, 45(4):  42-46.  DOI: 10.11930/j.issn.1004-9649.2012.4.42.4

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It is very important for transformer insulation design to calculate winding potential distribution of the transformer with subsection and layer winding under VFTO (Very Fast Transient Over-voltage). VFTO generated by GIS switchgear switching is very harmful to transformer insulation. In order to accurately simulate the very fast transient process in the winding, a lumped parameter model with single layer winding unit is proposed. Physical model and math formula for the calculation of inductance, capacitance and resistance parameters are introduced. The consistency between simulation and measurement results in an actual transformer winding verifies the correctness of proposed model, which provides theoretical basis for transformer winding insulation design.

Application and analysis of DSM and energy storage technology for industrial peak load management

DONG Li-tong¹，²， XU Jun¹，LIU Hai-bo¹，²

2012, 45(4):  47-50.  DOI: 10.11930/j.issn.1004-9649.2012.4.47.3

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The development of industry mainly relies on electricity. Currently, power shortage is serious problem which limits the development of industrial economy. Related technologies such as Demand Side Management （DSM） and energy storage are needed for industry users to solve this problem. The application conditions and implementation effects of these technologies in peak load management were introduced. The application in milk industry verifies the effectiveness of these technologies. Both peak load demand and electricity expenditures for industrial users are reduced in the study. The analysis results can provide certain basis in decision-making for both power supply enterprise and industrial users.

Generation Technology

Research and application on new type split direct flow burner in W-flame boiler

CHEN Yu-zhong, SHI Jian, LUO Xiao-peng, HOU Yu-bo

2012, 45(4):  51-53.  DOI: 10.11930/j.issn.1004-9649.2012.4.51.2

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For the problems of the poor combustion stability, low combustion efficiency and severely slagging in W flame boiler split burner, based on the analysis of combustion principle and the numerical simulation experiment, a new type split direct flow burner was designed. The exhaust gas fire nozzle was laid in two secondary air areas next to the furnace center. A secondary air nozzle was laid in a primary air nozzle next to water wall. The results show that new type split burner enhance the combustion stability and combustion efficiency of the boiler, and slagging can be effectively controlled.

Low NO_x combustion reformation and operation adjustment in 600 MW tangential firing boiler

YING Ming-liang, PAN Guo-qing, DAI Cheng-feng, XU Liang, XU Chang, HU Wei-feng, XU Zhong-xiong, TU Xiao-bao

2012, 45(4):  54-58.  DOI: 10.11930/j.issn.1004-9649.2012.4.54.4

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The air-staged and low NO_x combustion technology in a 600 MW tangential firing boiler was researched. The comparison of nitrogen oxide emission concentration before and after the reformation was analyzed. The results show that the NO_x emission concentration of boiler was reduced obviously. The NO_x emission concentration was reduced about 50% when the unit load was over 350 MW. The results of the operation adjustment test show that the SOFA air flow, auxiliary air damper opening, secondary air box and furnace differential pressure have larger influence on NO_x emission.

Blowpipe technology of once through boiler in 660 MW ultra-supercritical unit

XIA Yong-jun, CHEN Lin-guo, ZHU Yun-peng, JIANG Wei-guo

2012, 45(4):  59-63.  DOI: 10.11930/j.issn.1004-9649.2012.4.59.4

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According to engineering practice, the blowpipe technology and control difficulty of once through boiler in 660 MW ultra-supercritical unit were summarized. Two blowpipe technologies with pressure-stabilizing method and pressure-reducing method were expounded separately. The pressure-reducing methods with boiler water circulation pump and without boiler water circulation pump were analyzed. The practice shows that when auxiliary equipments reach the condition of blowpipe, the pressure-stabilizing method was easier to control than pressure-reducing method, the inspection standard of the two methods was same, and there were no obvious differences of the effect between the two methods. The results have practical guidance significance for the future engineering practices.

Research and application on signal anti-interference of distributed control system in thermal power plant

ZHOU Qian, LU Xue-nong, ZHANG Wen-jing

2012, 45(4):  64-67.  DOI: 10.11930/j.issn.1004-9649.2012.4.64.3

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To solve the problem of signal interference in distributed control system （DCS） of thermal power plant, five interferences were analyzed. The interferences were system internal interference, power disturbances, conduction disturbances, grounding interference and radiation interference. Six anti-interference measures, which were isolation device, power selecting, cable selecting, cable laying, effective filter, properly grounding, were proposed. The causes and solutions for abnormal fluctuation of boiler drum level signal and drum pressure signal in a 2×300 MW unit were systematically analyzed. Three notable requirements in the anti-interference process of design, construction and operation of the DCS in the thermal power plant were proposed. The results can provide reference for the technicians of the power plant.

Energy Conservation and Environmental Protection

Target optimization of wet flue gas desulfurization control system in 330 MW unit

LIU Yan-quan, NIU Cheng-lin, CHENG Hai-yan, LIU Xin

2012, 45(4):  68-72.  DOI: 10.11930/j.issn.1004-9649.2012.4.68.4

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DepartmenBased on the history operation data of flue gas desulfurization （FGD） system in thermal power plant, using data mining method, several important operation parameters were optimized. The optimal operation parameters values, which can meet the required desulphurization efficiency and the maximum economic efficiency, were confirmed. A fuzzy association rule mining algorithm was proposed to determine the optimization target of limestone-gypsum wet FGD in a 330 MW unit. Firstly, the fuzzy data set of history data was structured by the competitive agglomeration algorithm that can determine the cluster number and soften the demarcation of the boundaries. Secondly, for meeting the desulfurization efficiency, treating the economic benefit as optimization objective, using fuzzy Apriori association rules algorithm for data mining, the frequent item set was gained. Finally, the optimal objective value of the operation parameters was obtained. The experimental results and theoretical analysis show that the mining results can contribute to the economic operation of desulfurization system in power plant and can provide the important reference for the optimal operation of unit.t of Automation, North China Electric Power University, Baoding 071003,China

Control strategy for sulfur dioxide under new standard in coal-fired power plant

XU Yue-yang, XUE Jian-ming, GUAN Yi-ming, WANG Hong-liang, LIU Tao

2012, 45(4):  73-77.  DOI: 10.11930/j.issn.1004-9649.2012.4.73.4

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According to the new revised GB13223-2011 emission standard of air pollutants for thermal power plant, China has become the strictest country of the SO2 control standard in the world. For meeting the new standard, SO2 control countermeasures of coal-fired power plants were researched. The evolution of sulfur dioxide emission standard, the development process of desulfurization and control situation in thermal power plant were introduced. The problems of traditional flue gas desulfurization technology were summarized. For satisfying the new standard, the relevant countermeasures in design, operation, management and technologies were proposed. Several effective, reclaimable and without secondary pollution processes of desulfurization were introduced, which can provide reference for the operation and management of desulfurization equipment and for the selection of the desulfrization technology.

New Energy

Short-term wind speed forecasting model based on ARMA-LSSVM and wavelet transform

ZHAO Hui¹, LI Bin¹, LI Biao², YUE You-jun¹

2012, 45(4):  78-81.  DOI: 10.11930/j.issn.1004-9649.2012.4.78.3

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A wind speed forecasting with high accuracy can effectively reduce or avoid the adverse effect of wind farm on power grids, meanwhile it can enhance the competitive ability of wind power in electricity market. A short-term wind speed forecasting method based on auto-regressive moving average （ARMA） model and least square support vector machine （LS-SWM） model was proposed. By using wavelet transform method, the historical load data was decomposed into series with different frequency characteristics. The low frequency components were predicted by LS-SVM model, while the high frequency components were predicted by ARMA model. The final forecasting results were obtained with wavelet reconstruction. Research results show that the prediction accuracy is different from each method. The mean square error of the proposed hybrid forecast model is 11.5%, better than the results by single forecasting methods.

Voltage security analysis on the distribution network with the integration of wind power by using stochastic power flow

DONG Wei, YU Jian-ming, YANG Meng-meng

2012, 45(4):  82-86.  DOI: 10.11930/j.issn.1004-9649.2012.4.82.4

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By using stochastic power flow, Cornish-Fisher normal expansion and covariance matrix transformation method, a new method to investigate the voltage security of a distribution network with integration of wind power was proposed. Considering wind speed randomness and other stochastic disturbances caused by varying loads and wind power generation units, the probabilistic distributions of node voltage violation constraints were obtained. The presented method was tested on a distribution network in Zhejiang province. The impacts of different wind power connection points and load capacities on voltage security were also analyzed.

Short-term generation forecasting for photovoltaic system based on CAPSO-RNN algorithm

ZHAO Jie, ZHANG Yan-xia

2012, 45(4):  87-91.  DOI: 10.11930/j.issn.1004-9649.2012.4.87.4

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Considering the characteristics of photovoltaic （PV） systems and various factors which will affect the power generation of PV systems, a short-term generation forecasting model of PV systems was proposed based on recurrent neural network （RNN） and chaos adaptive particle swarm optimization （CAPSO） algorithm. In the model, the weights and thresholds of RNN were optimized by the global optimization ability of CAPSO algorithm in order to avoid the disadvantages of the traditional RNN, such as slow convergence and prone to local minimum. The fuzzy membership function was used to process the data in the temperature evaluation, which can improve generation forecasting precision. Forecasting results show the high accuracy of the proposed model.

Technical and economic analysis on V2G peak power support mode

LIAO Qiang-qiang¹, ZHOU Guo-ding¹, GE Hong-hua¹, JIANG Xin-ze², ZNANG Yu², QIAN Hong³, LI Xiao-hua³, ZHANG Shen-yang¹

2012, 45(4):  92-95.  DOI: 10.11930/j.issn.1004-9649.2012.4.92.3

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Vehicle-to-grid （V2G） mode is adopted in urban power grid for load shifting due to grid features such as big peak load and short time duration. The electric vehicles charge during night and send power back to grid during peak time in the day. The method can effectively flatten the load curve and improve energy utilization efficiency. Analysis was performed on an electric vehicle fleet with 30 kW?h battery per vehicle in Shanghai district grid which has 12 hours of 800 MW peak load annually. The economic evaluation of costs and profits indicates that both vehicle owners and utilities can benefit from V2G mode. Same as wind power and solar power, V2G is an energy saving, environment friendly and sustainable development energy mode.

Information and Communication

Research on 3D GIS-based grid video surveillance system

YAO Nan¹, WANG Kai-sheng²

2012, 45(4):  96-100.  DOI: 10.11930/j.issn.1004-9649.2012.4.96.4

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Grid video surveillance system is an important part of smart grid. 3D GIS-based grid video surveillance system combines 3D GIS technology and video monitoring technology, displays control points by 3D GIS spatial layout, and concentrates on the grid equipment monitoring. Operation steps and monitor equipment are decreased by using camera preset positions. With 3D GIS as the monitoring background, the bidirectional interaction among 3D vision, perspectives and camera preset location can be used for emergency management decision support and 3D simulation exercises by applying best path analysis method. The system is made up of station system，monitoring platform and client. Monitoring platform is composed of 3D GIS and video platform. 3D GIS platform provides 3D GIS service to video platform by component invocation. Multiple data organization and spatial index optimization techniques are used in the system. Oracle database is selected to integrate and manage multi-source data. Multistage and piecemeal processing technology is applied to process three dimensional data. Signal softswitch technology based on SIP protocol is adopted to manage video data. Video monitoring for long span transmission tower is taken as the example for explaining the system construction and usage conditions.

Electric Power Economy

Scenario analysis on mid-long term energy and electricity demand and carbon emission in China

XU Min-jie, HU Zhao-guang, TAN Xian-dong，SHAN Bao-guo

2012, 45(4):  101-107.  DOI: 10.11930/j.issn.1004-9649.2012.4.101.6

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By comprehensive consideration of future economic development and the production volume in major industries, the scenarios analysis model of mid-long term energy and electricity demand and carbon emission in China by “bottom-up” method was constructed. The primary energy, electricity demand, energy structure and carbon emission in 2015, 2020 and 2030 of three different circumstances were forecasted. The ratio of non-fossil energy and carbon emission intensity were measured and calculated. The results show that the primary energy demand in China could be raised to about 5 billion tons of standard coal, and the electricity demand could be raised to about 7.7 PW?h by 2020. If maximize the use of all kinds of clean energy, the carbon emission intensity in 2020 can be reduced more than 40%~45% of the carbon emission intensity in 2005, and the ratio of non-fossil energy consumption in primary energy consumption could be raised to 15% by 2020 in all the three economic development circumstances.

Analysis on maturity of energy saving service industry in China

ZHANG Yan-hua, CHENG Gang

2012, 45(4):  108-111.  DOI: 10.11930/j.issn.1004-9649.2012.4.108.3

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According to the industry life cycle theory, based on industry scale index, the stage partition and the position of energy saving service industry were analyzed. The results show that the energy saving service industry was a growing industry in short-term future, and will grow up towards maturity period gradually. The market segmentations will be diversified and the industry integration will be accelerated in future.