Power grid construction projects are distinguished by their wide variety,high investment,long payback period,and close relation to national development and human welfare.To improve the investment accuracy in such proj...Power grid construction projects are distinguished by their wide variety,high investment,long payback period,and close relation to national development and human welfare.To improve the investment accuracy in such projects and effectively prevent investment risks,this paper proposes an investment optimization decision-making method for multiple power grid construction projects under a certain investment scale.Firstly,an in-depth analysis of the characteristics and development requirements of China’s power grid projects was performed.Thereafter,the time sequence and holographic method was adopted to conduct multi-dimensional,multi-perspective risk assessment of different parts of power grid projects,and a holographic risk assessment index system was developed.Moreover,an investment decision model considering the comprehensive risk based on combination weighting was developed according to the output and input of power grid construction projects.A new combination weighting optimization method that takes into account the investment willingness of enterprises was designed to improve the current weighting evaluation methods.Finally,the validity and applicability of the proposed evaluation method were verified by case examples.展开更多
The environmental pollution,as well as gradual depletion of mineral resources has encouraged the world to move into renewable energy sources for generation of electricity.At present,the cost of using renewable energy ...The environmental pollution,as well as gradual depletion of mineral resources has encouraged the world to move into renewable energy sources for generation of electricity.At present,the cost of using renewable energy sources,such as sunshine and wind in electricity generation has significantly reduced.This has led to higher penetration of renewable energy into the grid.However,both wind and solar energy photovoltaics are unpredictable energies which reduce the reliability and resiliency of the grid.The integration of battery energy storage system in the grid is one of the proficient solutions to the problem.There are numerous grid connected renewable energy based battery projects that have been deployed in different countries around the world for research,development and commercial application.This review paper will discuss some of the projects based on the battery connected wind and solar energy power generation systems that can operate both in grid connected and grid independent modes.The projects discussed in this paper are selected based on the availability of information.The battery energy storage system(BESS)incorporated in each of the project is found to increase the stability and performance of the grid by addressing the mismatch between power generation and the load of the grid created due to intermittent nature of renewable energy sources.展开更多
This paper proposes an innovative supervision method that can provide project supervisors with realtime supervision of engineering projects and contractor activity. To obtain real-time and comprehensive state of proje...This paper proposes an innovative supervision method that can provide project supervisors with realtime supervision of engineering projects and contractor activity. To obtain real-time and comprehensive state of project, we use grid management to divide the project supervision grid in three levels: stage, objective, and milestone. Then, a detailed supervision mechanism is designed to help supervisors measure the project situation in real time. This mechanism checks that if the project objectives(such as schedule, cost, quality, and safety) in every supervision grid cell are under the healthy limits, any project deviation can be identified as soon as possible.A schedule objective is selected as an example to illustrate the method used to calculate the healthy limit.展开更多
Using the improved prospect theory with the linear transformations of rewarding good and punishing bad(RGPBIT),a new investment ranking model for power grid construction projects(PGCPs)is proposed.Given the uncertaint...Using the improved prospect theory with the linear transformations of rewarding good and punishing bad(RGPBIT),a new investment ranking model for power grid construction projects(PGCPs)is proposed.Given the uncertainty of each index value under the market environment,fuzzy numbers are used to describe qualitative indicators and interval numbers are used to describe quantitative ones.Taking into account decision-maker’s subjective risk attitudes,a multi-criteria decision-making(MCDM)method based on improved prospect theory is proposed.First,the[−1,1]RGPBIT operator is proposed to normalize the original data,to obtain the best andworst schemes of PGCPs.Furthermore,the correlation coefficients between interval/fuzzy numbers and the best/worst schemes are defined and introduced to the prospect theory to improve its value function and loss function,and the positive and negative prospect value matrices of the project are obtained.Then,the optimization model with the maximum comprehensive prospect value is constructed,the optimal attribute weight is determined,and the PGCPs are ranked accordingly.Taking four PGCPs of the IEEERTS-79 node system as examples,an illustration of the feasibility and effectiveness of the proposed method is provided.展开更多
On April 7, the construction of 110-kV Hechanglu intelligent substation in Tianjin Binhai New Area was started, inaugurating the comprehensive demonstration project for smart grid in Sino-Singapore Tianjin Eco-City.
The ecological environment promotes the construction of smart grids, while the smart substation is the key to the construction of smart grids. Based on the supervision of the Zigui 220 KV smart substation project in t...The ecological environment promotes the construction of smart grids, while the smart substation is the key to the construction of smart grids. Based on the supervision of the Zigui 220 KV smart substation project in the Three Gorges Reservoir Region of China, this paper studies how to well create the supervision for the smart substation project construction. With the research focus of “four-control, two-management and one-coordination” in the supervision and according to the problems and experience in the project construction, some reasonable suggestions are put forward, and then the accumulated methods and experience by supervisors when they are engaged in the supervision for the smart substation project construction are summarized.展开更多
Radial imaging techniques, such as projection-reconstruction （PR）, are used in magnetic resonance imaging （MRI） for dynamic imaging, angiography, and short-T2 imaging. They are less sensitive to flow and motion ar...Radial imaging techniques, such as projection-reconstruction （PR）, are used in magnetic resonance imaging （MRI） for dynamic imaging, angiography, and short-T2 imaging. They are less sensitive to flow and motion artifacts, and support fast imaging with short echo times. However, aliasing and streaking artifacts are two main sources which degrade radial imaging quality. For a given fixed number of k-space projections, data distributions along radial and angular directions will influence the level of aliasing and streaking artifacts. Conventional radial k-space sampling trajectory introduces an aliasing artifact at the first principal ring of point spread function （PSF）. In this paper, a shaking projection （SP） k-space sampling trajectory was proposed to reduce aliasing artifacts in MR images. SP sampling trajectory shifts the projection alternately along the k-space center, which separates k-space data in the azimuthal direction. Simulations based on conventional and SP sampling trajectories were compared with the same number projections. A significant reduction of aliasing artifacts was observed using the SP sampling trajectory. These two trajectories were also compared with different sampling frequencies. ASP trajectory has the same aliasing character when using half sampling frequency （or half data） for reconstruction. SNR comparisons with different white noise levels show that these two trajectories have the same SNR character. In conclusion, the SP trajectory can reduce the aliasing artifact without decreasing SNR and also provide a way for undersampling recon- struction. Furthermore, this method can be applied to three-dimensional （3D） hybrid or spherical radial k-space sampling for a more efficient reduction of aliasing artifacts.展开更多
An exclusive interview with the author was published in Issue 2, 2010 of this journal, in which the starting point and macro-strategy to construct smart grid in China was presented. Meanwhile, the three periods of sma...An exclusive interview with the author was published in Issue 2, 2010 of this journal, in which the starting point and macro-strategy to construct smart grid in China was presented. Meanwhile, the three periods of smart grid construction were also mentioned, namely planning and pilot project construction period, overall construction period, and improvement and upgrade period as it is planned by SGCC. At the invitation of this journal, the author wrote another article to further elaborate the implementation in the f irst period of SGCC smart grid program. The article will be published in two consecutive issues. The f irst part of the article was published in Issue 3, 2010. This is the second part of the article.展开更多
The construction of intercontinental power grid interconnection projects is key to realizing the vision of Global Energy Interconnection,which is to solve global energy problems in a clean and sustainable manner.These...The construction of intercontinental power grid interconnection projects is key to realizing the vision of Global Energy Interconnection,which is to solve global energy problems in a clean and sustainable manner.These projects may be influenced by a few factors that are neither technological nor economic,such as political,social,and international factors.This paper thus presents a multi-level model for recognizing which factor from a compiled list of 14 would impact a particular intercontinental interconnection project and for assessing the degree of the factor’s influence.In the first part of the model,the Analytic Hierarchy Process(AHP)method is used to recognize the project’s most significant impact factors.Using the recognition results,the second part of the model can assess the degree of the factor’s influence on the project based on ratings provided by experts.A comprehensive evaluation can thus be provided.As a case study,the proposed Saudi Arabia-Ethiopia power grid interconnection project connecting Asia and Africa was analyzed.Derived from a combination of multiple opinions from experts,evaluations from the model will be of direct benefit to decision-makers,investors,project implementers,and engineers,providing them with a deeper insight into the project.展开更多
China needs to develop a strong national power grid which takes ultra-high-voltage (UHV) transmission systems as its core. The grid is expected to adopt 1000-kV-class AC and ± 800-kV DC transmission systems. In v...China needs to develop a strong national power grid which takes ultra-high-voltage (UHV) transmission systems as its core. The grid is expected to adopt 1000-kV-class AC and ± 800-kV DC transmission systems. In view of significant achievements in technological research and considerable progress in UHV manufacturing technology, China is capable of developing UHV systems. In order to promote the construction of UHV systems,China Electric Power Research Institute and other institutions have initiated first-phase research activities of UHV transmission technologies. The main contents involve research on UHV transmission technology and its economy,developing and manufacturing abilities on UHV equipment, prospective of UHV network frame and selection of demonstration projects, etc.展开更多
An exclusive interview with the author was published in Issue 2,2010 of this journal,in which the starting point and macro-strategy to construct smart grid in China was presented.Meanwhile,the three periods of smart g...An exclusive interview with the author was published in Issue 2,2010 of this journal,in which the starting point and macro-strategy to construct smart grid in China was presented.Meanwhile,the three periods of smart grid construction were also mentioned,namely planning and pilot project construction period,overall construction period,and improving and upgrading period as it is planned by SGCC.At the invitation of this journal,the author wrote an article further introducing the implementation in the first period of SGCC smart grid program.The article will be published in two consecutive issues.展开更多
基金supported by the State Grid Science and Technology Project (SGTYHT/16-JS-198)
文摘Power grid construction projects are distinguished by their wide variety,high investment,long payback period,and close relation to national development and human welfare.To improve the investment accuracy in such projects and effectively prevent investment risks,this paper proposes an investment optimization decision-making method for multiple power grid construction projects under a certain investment scale.Firstly,an in-depth analysis of the characteristics and development requirements of China’s power grid projects was performed.Thereafter,the time sequence and holographic method was adopted to conduct multi-dimensional,multi-perspective risk assessment of different parts of power grid projects,and a holographic risk assessment index system was developed.Moreover,an investment decision model considering the comprehensive risk based on combination weighting was developed according to the output and input of power grid construction projects.A new combination weighting optimization method that takes into account the investment willingness of enterprises was designed to improve the current weighting evaluation methods.Finally,the validity and applicability of the proposed evaluation method were verified by case examples.
文摘The environmental pollution,as well as gradual depletion of mineral resources has encouraged the world to move into renewable energy sources for generation of electricity.At present,the cost of using renewable energy sources,such as sunshine and wind in electricity generation has significantly reduced.This has led to higher penetration of renewable energy into the grid.However,both wind and solar energy photovoltaics are unpredictable energies which reduce the reliability and resiliency of the grid.The integration of battery energy storage system in the grid is one of the proficient solutions to the problem.There are numerous grid connected renewable energy based battery projects that have been deployed in different countries around the world for research,development and commercial application.This review paper will discuss some of the projects based on the battery connected wind and solar energy power generation systems that can operate both in grid connected and grid independent modes.The projects discussed in this paper are selected based on the availability of information.The battery energy storage system(BESS)incorporated in each of the project is found to increase the stability and performance of the grid by addressing the mismatch between power generation and the load of the grid created due to intermittent nature of renewable energy sources.
基金the National Natural Science Foundation of China(No.71271085)the Beijing "12th Five-Year Plan" Project of Philosophy and Social Sciences(No.12JGB044)
文摘This paper proposes an innovative supervision method that can provide project supervisors with realtime supervision of engineering projects and contractor activity. To obtain real-time and comprehensive state of project, we use grid management to divide the project supervision grid in three levels: stage, objective, and milestone. Then, a detailed supervision mechanism is designed to help supervisors measure the project situation in real time. This mechanism checks that if the project objectives(such as schedule, cost, quality, and safety) in every supervision grid cell are under the healthy limits, any project deviation can be identified as soon as possible.A schedule objective is selected as an example to illustrate the method used to calculate the healthy limit.
文摘Using the improved prospect theory with the linear transformations of rewarding good and punishing bad(RGPBIT),a new investment ranking model for power grid construction projects(PGCPs)is proposed.Given the uncertainty of each index value under the market environment,fuzzy numbers are used to describe qualitative indicators and interval numbers are used to describe quantitative ones.Taking into account decision-maker’s subjective risk attitudes,a multi-criteria decision-making(MCDM)method based on improved prospect theory is proposed.First,the[−1,1]RGPBIT operator is proposed to normalize the original data,to obtain the best andworst schemes of PGCPs.Furthermore,the correlation coefficients between interval/fuzzy numbers and the best/worst schemes are defined and introduced to the prospect theory to improve its value function and loss function,and the positive and negative prospect value matrices of the project are obtained.Then,the optimization model with the maximum comprehensive prospect value is constructed,the optimal attribute weight is determined,and the PGCPs are ranked accordingly.Taking four PGCPs of the IEEERTS-79 node system as examples,an illustration of the feasibility and effectiveness of the proposed method is provided.
文摘On April 7, the construction of 110-kV Hechanglu intelligent substation in Tianjin Binhai New Area was started, inaugurating the comprehensive demonstration project for smart grid in Sino-Singapore Tianjin Eco-City.
文摘The ecological environment promotes the construction of smart grids, while the smart substation is the key to the construction of smart grids. Based on the supervision of the Zigui 220 KV smart substation project in the Three Gorges Reservoir Region of China, this paper studies how to well create the supervision for the smart substation project construction. With the research focus of “four-control, two-management and one-coordination” in the supervision and according to the problems and experience in the project construction, some reasonable suggestions are put forward, and then the accumulated methods and experience by supervisors when they are engaged in the supervision for the smart substation project construction are summarized.
基金Project supported by the National Basic Research Program of China(Grant No.2011CB707701)the Innovation Fund for Technology Based Firms,China(Grant No.11C26221103870)+1 种基金the National High Technology Research and Development Program of China(Grant Nos.2011BAI12B05 and 2011BAI23B07)the National Natural Science Foundation of China(Grant Nos.81171330,81271664,and 81230035)
文摘Radial imaging techniques, such as projection-reconstruction （PR）, are used in magnetic resonance imaging （MRI） for dynamic imaging, angiography, and short-T2 imaging. They are less sensitive to flow and motion artifacts, and support fast imaging with short echo times. However, aliasing and streaking artifacts are two main sources which degrade radial imaging quality. For a given fixed number of k-space projections, data distributions along radial and angular directions will influence the level of aliasing and streaking artifacts. Conventional radial k-space sampling trajectory introduces an aliasing artifact at the first principal ring of point spread function （PSF）. In this paper, a shaking projection （SP） k-space sampling trajectory was proposed to reduce aliasing artifacts in MR images. SP sampling trajectory shifts the projection alternately along the k-space center, which separates k-space data in the azimuthal direction. Simulations based on conventional and SP sampling trajectories were compared with the same number projections. A significant reduction of aliasing artifacts was observed using the SP sampling trajectory. These two trajectories were also compared with different sampling frequencies. ASP trajectory has the same aliasing character when using half sampling frequency （or half data） for reconstruction. SNR comparisons with different white noise levels show that these two trajectories have the same SNR character. In conclusion, the SP trajectory can reduce the aliasing artifact without decreasing SNR and also provide a way for undersampling recon- struction. Furthermore, this method can be applied to three-dimensional （3D） hybrid or spherical radial k-space sampling for a more efficient reduction of aliasing artifacts.
文摘An exclusive interview with the author was published in Issue 2, 2010 of this journal, in which the starting point and macro-strategy to construct smart grid in China was presented. Meanwhile, the three periods of smart grid construction were also mentioned, namely planning and pilot project construction period, overall construction period, and improvement and upgrade period as it is planned by SGCC. At the invitation of this journal, the author wrote another article to further elaborate the implementation in the f irst period of SGCC smart grid program. The article will be published in two consecutive issues. The f irst part of the article was published in Issue 3, 2010. This is the second part of the article.
基金supported by the State Grid Science and Technology Project“Research on Method and Evaluation Principle for the Cross-Continent Power Transmission Planning Scheme”(SGTYHT/16-JS-198)。
文摘The construction of intercontinental power grid interconnection projects is key to realizing the vision of Global Energy Interconnection,which is to solve global energy problems in a clean and sustainable manner.These projects may be influenced by a few factors that are neither technological nor economic,such as political,social,and international factors.This paper thus presents a multi-level model for recognizing which factor from a compiled list of 14 would impact a particular intercontinental interconnection project and for assessing the degree of the factor’s influence.In the first part of the model,the Analytic Hierarchy Process(AHP)method is used to recognize the project’s most significant impact factors.Using the recognition results,the second part of the model can assess the degree of the factor’s influence on the project based on ratings provided by experts.A comprehensive evaluation can thus be provided.As a case study,the proposed Saudi Arabia-Ethiopia power grid interconnection project connecting Asia and Africa was analyzed.Derived from a combination of multiple opinions from experts,evaluations from the model will be of direct benefit to decision-makers,investors,project implementers,and engineers,providing them with a deeper insight into the project.
文摘China needs to develop a strong national power grid which takes ultra-high-voltage (UHV) transmission systems as its core. The grid is expected to adopt 1000-kV-class AC and ± 800-kV DC transmission systems. In view of significant achievements in technological research and considerable progress in UHV manufacturing technology, China is capable of developing UHV systems. In order to promote the construction of UHV systems,China Electric Power Research Institute and other institutions have initiated first-phase research activities of UHV transmission technologies. The main contents involve research on UHV transmission technology and its economy,developing and manufacturing abilities on UHV equipment, prospective of UHV network frame and selection of demonstration projects, etc.
文摘An exclusive interview with the author was published in Issue 2,2010 of this journal,in which the starting point and macro-strategy to construct smart grid in China was presented.Meanwhile,the three periods of smart grid construction were also mentioned,namely planning and pilot project construction period,overall construction period,and improving and upgrading period as it is planned by SGCC.At the invitation of this journal,the author wrote an article further introducing the implementation in the first period of SGCC smart grid program.The article will be published in two consecutive issues.
