Very fast transient over-voltage （VFTO）, induced by disconnector operations in gas- insulated switchgears, has become the limiting dielectric stress at ultra-high voltage levels. Much work has been done to investiga...Very fast transient over-voltage （VFTO）, induced by disconnector operations in gas- insulated switchgears, has become the limiting dielectric stress at ultra-high voltage levels. Much work has been done to investigate single-strike waveforms of VFTO. However, little study has been carried out investigating the repeated strike process, which would influence VFTO significantly. In this paper, we carried out 450 effective experiments in an ultra-high voltage test circuit, and conducted calculations through the Monte Carlo simulation method, to investigate the repeated strike process. Firstly, the mechanism of the repeated strike process is proposed, based on the ex- perimentai results. Afterwards, statistical breakdown characteristics of disconnectors are obtained and analyzed. Finally, simulations of the repeated strike process are conducted, which indicate that the dielectric strength recovery speed and polarity effect factor have a joint effect on VFTO. This study enhances the understanding of the nature of VFTO, and may help to optimize the disconnector designed to minimize VFTO.展开更多
In view of the imbalanced distribution of power load and resources, including the status of “electric shortage” in some cities in our country, the article discusses the long-distance transmission technology. It main...In view of the imbalanced distribution of power load and resources, including the status of “electric shortage” in some cities in our country, the article discusses the long-distance transmission technology. It mainly analyzed two ways of the long-distance transmission: UHV AC transmission and UHV DC transmission. The fractional frequency transmission technology and half wavelength AC transmission technology of AC transmission are introduced. Some key technologies of long-distance transmission are described. It has a guess for long-distance transmission future direction.展开更多
Under the background of sustainable energy transition and environmental protection,Global Energy Interconnection(GEI),which features an innovative combination of clean energy(e.g.,solar power) and ultra-high voltage(U...Under the background of sustainable energy transition and environmental protection,Global Energy Interconnection(GEI),which features an innovative combination of clean energy(e.g.,solar power) and ultra-high voltage(UHV) transmission technologies,provides a means to realize global climate governance.China is a large country with unevenly distributed water resources,energy production,and energy consumption,and the large areas of desert in northern and western China have the potential for installing large-scale solar power plants.This study analyzed the potential of using large-scale solar power from deserts to coastal seawater desalination plants,which could alleviate the freshwater crisis and control desertification in China.First,the measurement data from NASA were used to estimate the potential exploitable amount of solar energy in desert areas.A macro idea was proposed for the transmission of electrical power from inland integrated energy bases to coastal seawater desalination and pumping of freshwater to western China to combat desertification and alleviate the freshwater crisis.Based on this,the electricity demands for desalination and water redistribution were estimated.As a huge interruptible load,desalination and pumping systems could be used to suppress power fluctuations of the integrated energy bases.Finally,the fundamental support roles of UHV grids in large-scale renewable energy allocation and utilization were discussed.This analysis offers a theoretical framework to help realize efficient renewable energy generation and consumption and alleviate freshwater shortage.展开更多
The low frequency oscillation characteristics of East China Power Grid after commissioning of the first ultra-high voltage alternating current(UHVAC)project-the Huai-Hu UHVAC project are studied.Several low frequency ...The low frequency oscillation characteristics of East China Power Grid after commissioning of the first ultra-high voltage alternating current(UHVAC)project-the Huai-Hu UHVAC project are studied.Several low frequency oscillation cases occurred in East China Power Grid in the past few years are reviewed and summarized.Based on the analysis of the different typical operation modes,the main low frequency oscillation modes in East China Power Grid in the early stages of development of ultra-high voltage(UHV)are summarized,and the impacts of the significant power grid maintenance on low frequency oscillation characteristics are analyzed.Besides,the oscillation mode of UHV generators to East China Power Grid is researched,and the importance of the power system stabilizator(PSS)is emphasized.Furthermore,the comparative analysis between the time domain and the frequency domain is carried out,and the influences of the governing system on low frequency oscillation characteristics are revealed.Finally,both the focus and the direction of low frequency oscillation research are presented.展开更多
Based on the transmission line theory of the buried metallic structures, the concerned harmful effects to the buried oil and natural gas pipelines caused by the power line short-circuit fault are further discussed. A ...Based on the transmission line theory of the buried metallic structures, the concerned harmful effects to the buried oil and natural gas pipelines caused by the power line short-circuit fault are further discussed. A closed-form expression of the induced voltage caused by the short-circuit fault of the ultra-high voltage power （UHVAC） transmission line is given. The transmission line model of the buried pipeline is set up and a set of formulas for calculating induced voltage on the pipeline and the parameters of the buried pipeline in actual environment condition are given. At last, the characteristic of the harm^hl effects on the buried pipeline from the power line short-circuit fault are discussed.展开更多
基金supported in part by National Natural Science Foundation of China(No.51277106)in part by the National Basic Research Program of China(973 Program)(No.2011CB209405)
文摘Very fast transient over-voltage （VFTO）, induced by disconnector operations in gas- insulated switchgears, has become the limiting dielectric stress at ultra-high voltage levels. Much work has been done to investigate single-strike waveforms of VFTO. However, little study has been carried out investigating the repeated strike process, which would influence VFTO significantly. In this paper, we carried out 450 effective experiments in an ultra-high voltage test circuit, and conducted calculations through the Monte Carlo simulation method, to investigate the repeated strike process. Firstly, the mechanism of the repeated strike process is proposed, based on the ex- perimentai results. Afterwards, statistical breakdown characteristics of disconnectors are obtained and analyzed. Finally, simulations of the repeated strike process are conducted, which indicate that the dielectric strength recovery speed and polarity effect factor have a joint effect on VFTO. This study enhances the understanding of the nature of VFTO, and may help to optimize the disconnector designed to minimize VFTO.
文摘In view of the imbalanced distribution of power load and resources, including the status of “electric shortage” in some cities in our country, the article discusses the long-distance transmission technology. It mainly analyzed two ways of the long-distance transmission: UHV AC transmission and UHV DC transmission. The fractional frequency transmission technology and half wavelength AC transmission technology of AC transmission are introduced. Some key technologies of long-distance transmission are described. It has a guess for long-distance transmission future direction.
基金supported by the State Grid GEIGC Science and Technology Project(No.GEIGC-S-[2018]068,Title:Research on the impact of Global Energy Interconnection on energy transformation and energy center transfer and countermeasures program)
文摘Under the background of sustainable energy transition and environmental protection,Global Energy Interconnection(GEI),which features an innovative combination of clean energy(e.g.,solar power) and ultra-high voltage(UHV) transmission technologies,provides a means to realize global climate governance.China is a large country with unevenly distributed water resources,energy production,and energy consumption,and the large areas of desert in northern and western China have the potential for installing large-scale solar power plants.This study analyzed the potential of using large-scale solar power from deserts to coastal seawater desalination plants,which could alleviate the freshwater crisis and control desertification in China.First,the measurement data from NASA were used to estimate the potential exploitable amount of solar energy in desert areas.A macro idea was proposed for the transmission of electrical power from inland integrated energy bases to coastal seawater desalination and pumping of freshwater to western China to combat desertification and alleviate the freshwater crisis.Based on this,the electricity demands for desalination and water redistribution were estimated.As a huge interruptible load,desalination and pumping systems could be used to suppress power fluctuations of the integrated energy bases.Finally,the fundamental support roles of UHV grids in large-scale renewable energy allocation and utilization were discussed.This analysis offers a theoretical framework to help realize efficient renewable energy generation and consumption and alleviate freshwater shortage.
文摘The low frequency oscillation characteristics of East China Power Grid after commissioning of the first ultra-high voltage alternating current(UHVAC)project-the Huai-Hu UHVAC project are studied.Several low frequency oscillation cases occurred in East China Power Grid in the past few years are reviewed and summarized.Based on the analysis of the different typical operation modes,the main low frequency oscillation modes in East China Power Grid in the early stages of development of ultra-high voltage(UHV)are summarized,and the impacts of the significant power grid maintenance on low frequency oscillation characteristics are analyzed.Besides,the oscillation mode of UHV generators to East China Power Grid is researched,and the importance of the power system stabilizator(PSS)is emphasized.Furthermore,the comparative analysis between the time domain and the frequency domain is carried out,and the influences of the governing system on low frequency oscillation characteristics are revealed.Finally,both the focus and the direction of low frequency oscillation research are presented.
基金supported by the National Natural Science Foundation of China(60671055,61171051)the Doctorate Foundation of the Ministry of Education of China(200700130046)
文摘Based on the transmission line theory of the buried metallic structures, the concerned harmful effects to the buried oil and natural gas pipelines caused by the power line short-circuit fault are further discussed. A closed-form expression of the induced voltage caused by the short-circuit fault of the ultra-high voltage power （UHVAC） transmission line is given. The transmission line model of the buried pipeline is set up and a set of formulas for calculating induced voltage on the pipeline and the parameters of the buried pipeline in actual environment condition are given. At last, the characteristic of the harm^hl effects on the buried pipeline from the power line short-circuit fault are discussed.
