Liquid leak detection may represent a challenge for Oil&Gas operators,as indicated by operational feed-back and independent studies.Despite the availability of many different leak detection technologies,some syste...Liquid leak detection may represent a challenge for Oil&Gas operators,as indicated by operational feed-back and independent studies.Despite the availability of many different leak detection technologies,some systems may either fail to detect spills or generate frequent false alarms.In particular,possible soil contamination from pre-existing leaks and pollution carry-over by rain water is difficult to filter out by a leak sensing system.Typical case of false alarms relates to punctual sensors installed upstream the drain valve within the storage tank bunds,monitoring possible presence of leaks in rain water.Besides old soil contamination,other criteria should also be considered when selecting a spill detection technology,such as asset type to be monitored(storage tank,pipeline,…),system accuracy(minimum detectable quantity,ability to localize the leak),detection time,reliability over time,capital,installation and operating costs.The paper will include an evaluation of different external leak detection technologies with respect to the above-mentioned criteria,pointing out the capabilities and limitations of each system.Focus will be placed on reliability of leak monitoring systems in challenging environments.A new generation of digital,reusable sensing cables and probes,as well as the impact of sensitivity for different applications,will be discussed.Since leak sensor installation environment(positioning,adoption of special precautions,…)may significantly affect the system performance,different above ground and underground configurations will be presented,both for new builds and existing facilities.展开更多
This study proposes a new model of granary storage weight detection based on the Janssen model to satisfy the strategic requirements of granary storage quantity detection in China. The model theoretically elucidates t...This study proposes a new model of granary storage weight detection based on the Janssen model to satisfy the strategic requirements of granary storage quantity detection in China. The model theoretically elucidates the relationship between granary storage weight and bottom/side pressure. A new layout of pressure sensors along the inner and outer rings is also proposed to obtain the pressure value. The experimental results indicate that the detection error of the proposed model is significantly lower than 1% with respect to the low-cost detection system, and this effectively satisfies the actual requirement for real-time monitoring of granary storage quantity.展开更多
Renewable energy sources, such as photovoltaic wind turbines, and wave power converters, use power converters to connect to the grid which causes a loss in rotational inertia. The attempt to meet the increasing energy...Renewable energy sources, such as photovoltaic wind turbines, and wave power converters, use power converters to connect to the grid which causes a loss in rotational inertia. The attempt to meet the increasing energy demand means that the interest for the integration of renewable energy sources in the existing power system is growing, but such integration poses challenges to the operating stability. Power converters play a major role in the evolution of power system towards SmartGrids, by regulating as virtual synchronous generators. The concept of virtual synchronous generators requires an energy storage system with power converters to emulate virtual inertia similar to the dynamics of traditional synchronous generators. In this paper, a dynamic droop control for the estimation of fundamental reference sources is implemented in the control loop of the converter, including active and reactive power components acting as a mechanical input to the virtual synchronous generator and the virtual excitation controller. An inertia coefficient and a droop coefficient are implemented in the control loop. The proposed controller uses a current synchronous detection scheme to emulate a virtual inertia from the virtual synchronous generators. In this study, a wave energy converter as the power source is used and a power management of virtual synchronous generators to control the frequency deviation and the terminal voltage is implemented. The dynamic control scheme based on a current synchronous detection scheme is presented in detail with a power management control. Finally, we carried out numerical simulations and verified the scheme through the experimental results in a microgrid structure.展开更多
With the development of cloud computing technology, data can be outsourced to the cloud and conveniently shared among users. However, in many circumstances, users may have concerns about the reliability and integrity ...With the development of cloud computing technology, data can be outsourced to the cloud and conveniently shared among users. However, in many circumstances, users may have concerns about the reliability and integrity of their data. It is crucial to provide data sharing services that satisfy these security requirements. We introduce a reliable and secure data sharing scheme, using the threshold secret sharing technique and the ChaumPedersen zero-knowledge proof. The proposed scheme is not only effective and flexible, but also able to achieve the semantic security property. Moreover, our scheme is capable of ensuring accountability of users’ decryption keys as well as cheater identification if some users behave dishonestly. The efficiency analysis shows that the proposed scheme has a better performance in terms of computational cost, compared with the related work. It is particularly suitable for application to protect users’ medical insurance data over the cloud.展开更多
文摘Liquid leak detection may represent a challenge for Oil&Gas operators,as indicated by operational feed-back and independent studies.Despite the availability of many different leak detection technologies,some systems may either fail to detect spills or generate frequent false alarms.In particular,possible soil contamination from pre-existing leaks and pollution carry-over by rain water is difficult to filter out by a leak sensing system.Typical case of false alarms relates to punctual sensors installed upstream the drain valve within the storage tank bunds,monitoring possible presence of leaks in rain water.Besides old soil contamination,other criteria should also be considered when selecting a spill detection technology,such as asset type to be monitored(storage tank,pipeline,…),system accuracy(minimum detectable quantity,ability to localize the leak),detection time,reliability over time,capital,installation and operating costs.The paper will include an evaluation of different external leak detection technologies with respect to the above-mentioned criteria,pointing out the capabilities and limitations of each system.Focus will be placed on reliability of leak monitoring systems in challenging environments.A new generation of digital,reusable sensing cables and probes,as well as the impact of sensitivity for different applications,will be discussed.Since leak sensor installation environment(positioning,adoption of special precautions,…)may significantly affect the system performance,different above ground and underground configurations will be presented,both for new builds and existing facilities.
基金Supported by Natural Science Project of Henan Provincial Science and Technology Department(172106000013)State Key Laboratory of Grain Information Processing and Control,Ministry of Education(KFJJ-2016-102)Grain Information Processing Technology of University Science and Technology Innovation Team in Henan Province(16IRTSTHN026)
文摘This study proposes a new model of granary storage weight detection based on the Janssen model to satisfy the strategic requirements of granary storage quantity detection in China. The model theoretically elucidates the relationship between granary storage weight and bottom/side pressure. A new layout of pressure sensors along the inner and outer rings is also proposed to obtain the pressure value. The experimental results indicate that the detection error of the proposed model is significantly lower than 1% with respect to the low-cost detection system, and this effectively satisfies the actual requirement for real-time monitoring of granary storage quantity.
基金Swedish Research Council(VR)STandUP for Energy,MaRINET2 and Erasmus Mundus(EMINTE)Ph.D.Scholarship for the support of the work
文摘Renewable energy sources, such as photovoltaic wind turbines, and wave power converters, use power converters to connect to the grid which causes a loss in rotational inertia. The attempt to meet the increasing energy demand means that the interest for the integration of renewable energy sources in the existing power system is growing, but such integration poses challenges to the operating stability. Power converters play a major role in the evolution of power system towards SmartGrids, by regulating as virtual synchronous generators. The concept of virtual synchronous generators requires an energy storage system with power converters to emulate virtual inertia similar to the dynamics of traditional synchronous generators. In this paper, a dynamic droop control for the estimation of fundamental reference sources is implemented in the control loop of the converter, including active and reactive power components acting as a mechanical input to the virtual synchronous generator and the virtual excitation controller. An inertia coefficient and a droop coefficient are implemented in the control loop. The proposed controller uses a current synchronous detection scheme to emulate a virtual inertia from the virtual synchronous generators. In this study, a wave energy converter as the power source is used and a power management of virtual synchronous generators to control the frequency deviation and the terminal voltage is implemented. The dynamic control scheme based on a current synchronous detection scheme is presented in detail with a power management control. Finally, we carried out numerical simulations and verified the scheme through the experimental results in a microgrid structure.
基金the National Key R&D Program of China (No. 2017YFB0802000)the National Natural Science Foundation of China (Nos. 61772326 and 61572303)+4 种基金the Research Fund for International Young Scientists, China (No. 61750110528)National Cryptography Development FYind for the 13th Five- Year Plan, China (No. MMJJ20170216), the Foundation of State Key Laboratory of Information Security, China (No. 2017-MS- 03)the Fundamental Research Funds for the Central Universities, China (No. GK201702004)the Scientific Research Program Funded by Shaanxi Provincial Education Department, China (No. 16JK1109), the Provincial Natural Science Foundation Research Project of Shaanxi, China (No. 2017JQ6029)the Doctoral Scientific Fund Project of Shaanxi University of Science & Technology, China (No. BJ11-12).
文摘With the development of cloud computing technology, data can be outsourced to the cloud and conveniently shared among users. However, in many circumstances, users may have concerns about the reliability and integrity of their data. It is crucial to provide data sharing services that satisfy these security requirements. We introduce a reliable and secure data sharing scheme, using the threshold secret sharing technique and the ChaumPedersen zero-knowledge proof. The proposed scheme is not only effective and flexible, but also able to achieve the semantic security property. Moreover, our scheme is capable of ensuring accountability of users’ decryption keys as well as cheater identification if some users behave dishonestly. The efficiency analysis shows that the proposed scheme has a better performance in terms of computational cost, compared with the related work. It is particularly suitable for application to protect users’ medical insurance data over the cloud.
