Electric Power

Practice and prospect of China intelligent power utilization

WANG Guang-hui

2012, 45(1): 1-5. DOI: 10.11930/j.issn.1004-9649.2012.1.1.4

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Based on the analysis of international development status in the field of intelligent power utilization and smart grid construction practices in China, an intelligent power utilization architecture suitable for China is presented. In-depth analysis and discussion focusing on the key supporting technologies including cloud computing and internet of things is performed. With practices in intelligent community, intelligent building and intelligent industrial park, the data mining of power utilization data and construction of urban energy management network are discussed.

Development and enlightenment of smart grid in EU

BAI Ming-yue, LIU Jia-nan, ZHANG Xue-ping, GAO Ya-nan, WANG Yue-qing

2012, 45(1): 6-9. DOI: 10.11930/j.issn.1004-9649.2012.1.6.3

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There are differences between the development of smart grid in China and Europe in terms of key technology, asset ownership and management structure. Those differences result in different smart grid roadmaps and opportunities for two sides to share experience and achievements. The implementation of smart grid in Europe, led and promoted by EU, is characterized by features such as policy-dominated, user-involved, resource-integration and technology innovation. Its philosophy provides beneficial inspiration for smart grid practice in China in different perspectives including policy making, industry chain and technology development.

Impacts of the access of 750 kV system and super-power source on Changji power grid

ZHOU Xiao, SONG Yun-ting, TIAN Jian-she, ZHANG Zhi-qiang, LI Jing, HAO Yi, YANG Jing

2012, 45(1): 10-14. DOI: 10.11930/j.issn.1004-9649.2012.1.10.4

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Based on the development plan of UHV of State Grid Corporation of China and the planning grid of Changji in 2012, the current distribution, static security, transient stability, short circuit current level and power supply section of Changji grid after access of the 750 kV system and super-power source are analyzed. The short circuit current and transient stability of the planning grid for the year of 2015 are calculated too. The adaptability of the planning Changji grid is evaluated. The research results can provide advice in regional power network planning and operation.

A traction load modeling method based on equivalent transformation

ZHANG Rui, CAI Guo-wei, CHEN Xing-lei, QIU Jian, YU Zhi-hong

2012, 45(1): 15-19. DOI: 10.11930/j.issn.1004-9649.2012.1.15.4

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A model is established which transforms traction load equivalently to network short-term fault. Based on analysis on wiring model of Scott traction transformer, traction load on the transformer secondary side is transformed to primary side and connected to regional power network as short-term network fault. The impact, nonlinearity and asymmetry characteristics of traction load are represented in the model. The comparison between simulation results with PSASP software package based on both impact load model and transformation model shows the validity of the proposed method. The impact of traction load on power quality of regional power network is also analyzed based on the calculation of related power quality indexes.

The influence of instantaneously variable load on coal consumption rate in ultra supercritical unit

SUN Wei-peng, SUN Ye-zhu

2012, 45(1): 20-24. DOI: 10.11930/j.issn.1004-9649.2012.1.20.4

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By the instantaneously variable load experiments of different load rising rate, the amplitude, wave frequency and the coal consumption analysis in the 1 036 MW unit of Huaneng Haimen Power Plant were implemented. The results show that the coal consumption rate of rising load conditions was bigger than that of stable load conditions, and the coal consumption rate of dropping load conditions was smaller than that of stable conditions. The bigger the load fluctuation was, the bigger the coal consumption rate fluctuation was. The optimal rising load rate and the optimal scheduling mode were gained. The economical efficiency of unit operation was improved and the coal consumption rate was reduced. The experiments result can provide a theoretical basis for the energy saving, emission reducing, optimal operation mode and the energy saving scheduling.

Application of reverse osmosis in feed water treatment for once-through boiler in ultra supercritical units

LIANG Hua-jie, SU Wei, FU Qiang

2012, 45(1): 25-28. DOI: 10.11930/j.issn.1004-9649.2012.1.25.3

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To conserve fresh water resources,the sea water reverse osmosis（SWRO） desalination technology was used in feed water treatment of 1 000 MW ultra supercritical once-through boiler in Guangdong Huilai power plants. The system output capacity, effluent quality, desalinization ratio have reached the design requirements. The results prove that SWRO can meet the request of feed water treatment of large coastal power plant. The equipments and operation condition of SWRO system were introduced. The key problems of typical SWRO system, such as pretreatment system dosage adjustment, application of energy recovery device PX, anti permeate thick drain, and sampling methods in permeate were discussed.

Inhibition performance of polyepoxysuccinic acid and its mixtures in reclaimed water

CHEN Ying-min, YU feng, LI Dong-liang

2012, 45(1): 29-32. DOI: 10.11930/j.issn.1004-9649.2012.1.29.3

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According to the quality of the city reclaimed water used in the circulatory cooling water in the power plants, the anti-scaling synergy of PESA、PBTCA、MA-AA with calcium carbonate precipitation method were studied and the optimized compositional formulation（6 mg/L PESA +4 mg/L MA-AA +5 mg/L PBTCA）was screened out. The effects of temperature, pH, and HCO on inhibition rate in different scale inhibitors were examined. The result demonstrated that the optimized mixed formula had advantage in thermal and alkaline stability, which could be applied in circulating water system of high temperature and high pH. In addition, when the concentration of HCO increased, the inhibition rate of optimized mixed formula decreased a little. Therefore, this formula can be applied in circulating water system of high concentration of HCO.

Precipitates in INCONEL alloy 617 aged at high temperature

GUO Yan, ZHOU Rong-can, HOU Shu-fang, LIN Lin

2012, 45(1): 33-36. DOI: 10.11930/j.issn.1004-9649.2012.1.33.3

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The precipitates of the aged alloys were investigated by means of scanning electron microscope（SEM）and transmission electron microscope（TEM）. The results show that M₂₃C₆ and M₆C particles with face-centered cubic（FCC）structure precipitate at grain boundaries, inside grains and the γ′ phase particles with order FCC structure were situated at intragranular sites in the process of aging up to 10 000 h at 760 ℃. During aging up to 10 000 h, the precipitates inside grains remained basically stable. Precipitates discontinuously dispersed at grain boundaries for the alloy aged for 300~3 000 h, then aggregated and distributed continuously after 5 000 h aging. At the same time, the quantity of M₆C carbides increased substantially for the alloy aged for 5 000 h. The hardness of the alloy aged for 300 h increased substantially, then a maximum hardness value for the alloy aged for 1 000 h was achieved accompanying by a decrease of the hardness of the alloy aged at 5 000 h.

Economical efficiency of the technology using secondary hot air for heating cleaned outlet flue gas of the FGD

WANG Chun-chang

2012, 45(1): 37-40. DOI: 10.11930/j.issn.1004-9649.2012.1.37.3

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Fly ash deposition and wall up in the flue gas heater of the FGD is an old and difficult problem, and there is no better measure to resolve the problem. It is one of the innovations that the secondary hot air was used to heat the outlet flue gas of the FGD instead of the flue gas heater. The economical efficiency of the technology was theoretically discussed and analyzed in detail, and was compared with the economical efficiency using the steam heater. The results show that when using the technology of adding secondary hot air into the outlet flue gas of the FGD and the temperature of the clean flue gas increasing to 30 ℃, the net coal consumption rate was increased to more than 4.3 g /（kW·h）, which was at least 0.3 g /（kW·h） more than the net coal consumption rate when using technology of steam heater. It will largely limit the engineering application of the technology of adding secondary hot air into the outlet flue gas of the FGD.

Optimal operation of selective catalytic reduction （SCR） flue gas denitrification system in 1 000 MW unit

LIANG Chuan, SHEN Yue

2012, 45(1): 41-44. DOI: 10.11930/j.issn.1004-9649.2012.1.41.3

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The theory of the selective catalytic reduction（SCR） DeNO_x technology and the main design parameters of denitrification system in No.4 1 000 MW unit of Suizhong Power Plant were introduced. The performance evaluation of test data was analyzed. The optimal operation scheme was proposed. By adjusting the amount of ammonia in reactors of the local area, the uniform and stable distribution of NO_x was performed in the outlet of reactors. The desired efficiency of denitration, the minimum rate of ammonia escape and the finer controllable operation can be maintained. Then the amount of spraying ammonia escape was saved and the danger of air preheater was reduced. Based on environmental emissions standards of the denitrification system, the cost of the operation was taken into account and the protection purpose of the equipment safety was gained.

Comparative analysis of de-NOx catalysts with different operation-time

SHANG Xue-song, CHEN Jin-sheng, HU Gong-ren

2012, 45(1): 45-49. DOI: 10.11930/j.issn.1004-9649.2012.1.45.4

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The de-NOx catalysts with different operation-time were adopted. The comparative analysis on properties of the catalysts was made. The test and the analysis of SCR with different catalysts of 10 080, 25 145, 30 288 and 40 368 h were carried out. The results show that the last two ones, 30 288 （C3） and 40 368 h （C4）, have unsatisfactory denitration rate which is lower than 60 % after 30 000 hours operation. Their performances cannot meet designed demand of the power plant. Moreover, the techniques of XRD, SEM, BET, FT-IR, IC and ICP-MS were used to characterize the objectives with different operation-time. The results indicate that the aggregations cannot be found remarkably, and the crystal form of carrier maintains the anatase style. However, the data from SEM show that the active compound on the surface of the catalyst runs off along with the operation-time, which is consistent with the analysis obtained from FT-IR. In the meantime, the channels and mesopores of catalysts are influenced badly with the long operation-time. Besides, there are also some water-soluble ions and trace heavy metals deposited on the surface of the catalysts.

Optimal reserve distribution of a grid connected with large scale wind power

LIU Yang，LIU Jun-yong，CHEN Lei，XU Fei

2012, 45(1): 50-54. DOI: 10.11930/j.issn.1004-9649.2012.1.50.4

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Three types of generation load curves and corresponding variables were defined with respects to wind power and load forecast errors. With the consideration of security constraints against the wind power generator output changes caused by uncertain fluctuations，an optimal reserve distribution model of a grid connected with wind power was constructed. The comparison between the proposed and conventional simulation results on the IEEE-RTS24 system proves the validity of the proposed method. The impact of generator output and reserve distribution on coal consumption was also analyzed with different objective weights.

Optimization of micro-source output of a grid-connected micro-grid

WANG Zhen-hua, ZHU Gui-ping

2012, 45(1): 55-58. DOI: 10.11930/j.issn.1004-9649.2012.1.55.3

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Conforming to the system operation constraints, the optimization of micro-source outputs of a grid-connected micro-grid was conducted for different objectives, such as total power generation cost and consumption cost minimization, or the environmental benefit maximization. The mathematical model was established for a benchmark micro-grid system suggested by CIGRE which was consisted of a micro-turbine, fuel cells, two photovoltaic systems and a flywheel energy storage system. The numerical solution based on particle swarm optimization （PSO） was performed. Optimization results demonstrate the validity and feasibility of the proposed method.

Transfer method of micro-grid operation between grid-connected and islanding modes

WANG He, LI Guo-qing, LI Hong-peng, WANG Bo-yi

2012, 45(1): 59-63. DOI: 10.11930/j.issn.1004-9649.2012.1.59.4

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The proper implementation of grid-connected and islanding modes for a micro-grid can effectively improve the power supply reliability of important loads. The transfer method between the two operation modes was investigated. An automatic transfer method was proposed, which can give the identification of the micro-grid condition by monitoring the voltage phase angle and amplitude on both utility and micro-grid sides continuously. The simulation results of the micro-grid with a micro-turbine and fuel cells as distributed sources were analyzed by using the PSCAD/EMTDC software package. The results demonstrate that the proposed automation transfer method has the ability to transfer between the two operation modes seamlessly in planned or faulted conditions.

Wind power forecasting based on time series and SVM

LI Ran, KE Yong-qin, ZHANG Xiao-qian, TANG Fan

2012, 45(1): 64-68. DOI: 10.11930/j.issn.1004-9649.2012.1.64.4

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The accurate wind power forecasting can relieve the adverse effects of wind power plants on power systems and enhance the competitive ability of wind power plants in electricity markets. A wind power forecasting method is proposed based on time series method and support vector machine （SVM）. The mathematical model was built by time series method. The factors which have significant impacts on the wind power were selected as SVMs inputs. In order to improve forecasting accuracy, a method based on time series trace evolution was used to find SVM training samples which similar to the power at the forecasting point. The actual examples prove the improvement of wind power forecasting accuracy by using the time series-SVM method.

Analysis of intelligent construction of transmission lines in Zhejiang power grid

WANG Shao-hua1，LIU Li1，LIU Hao-jun1，WU Ming-xiang1，YIN Ming2

2012, 45(1): 69-72. DOI: 10.11930/j.issn.1004-9649.2012.1.69.3

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Intelligent construction of transmission lines is one of the key links for smart grid establishment, new energy sources development and wide range energy resources optimal allocation. The goal and planning of the intelligent construction of transmission lines in Zhejiang power grid are introduced. With application examples, the key technologies used in the construction are analyzed from the aspects of system condition monitoring, intelligent inspection system with helicopters, geographic information system （GIS） and power transmission equipment condition evaluation. The intelligent construction of transmission lines is of great significance to improve maintenance efficiency and transmission line operation.

Monitoring scheme for common grounding electrode disconnector based on GPRS/CDMA technology

WANG Chun-cheng

2012, 45(1): 73-77. DOI: 10.11930/j.issn.1004-9649.2012.1.73.4

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The common ground pole design of multi-circuit UHVDC/HVDC system has become the developing trend of UHVDC/HVDC system ground pole design in order to save pole sites and cost. At present, position and status of the electrode side disconnector can only be monitored manually which is inefficient and expensive for the project life cycle. A feasible scheme based on GPRS/CDMA communication technology and solar wind hybrid power generation is proposed to provide cost effective and efficient disconnector remote monitoring for system opeartion and construction. The method adpots many mature technologies such as GPRS/CDMA communication, clean energy generation, smart microgrid and high voltage insulation monitoring.

Quality control and management of welding engineering in ultra supercritical/supercritical unit

YAN Su-xing, CAI Wen-he, WANG Xiao-ying, WANG Gan-gang, LIANG Jun, WANG Bao-chen

2012, 45(1): 78-81. DOI: 10.11930/j.issn.1004-9649.2012.1.78.3

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The situation and tasks of the welding quality control during the installation process in the ultra supercritical and supercritical unit were introduced. The relationship between welding quality, construction duration and safety was analyzed. And based on the analysis and summary of lots of practical problems in the welding engineering, a set of feasible management mode was proposed. In order to ensure the quality of welding construction, the method of issuing the "welding group certificate" was recommended.

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