A unified optimal power flow(OPF) model for AC/DC grids integrated with natural gas systems is proposed for the real-time scheduling of power systems.Herein, the primary physical couplings underlying this coordinated ...A unified optimal power flow(OPF) model for AC/DC grids integrated with natural gas systems is proposed for the real-time scheduling of power systems.Herein, the primary physical couplings underlying this coordinated system are modeled and investigated. In addition, the uncertainties of gas loads are considered when studying the role of gas supply for gas-fired units in power system operations. The nonlinear gas system constraints are converted to the second-order cone forms that allow for the use of the Benders decomposition techniques and the interior-point method to obtain the optimal solution. The numerical results of the modified IEEE 118-bus test system that integrates the Belgium 20-node natural gas system demonstrate the effectiveness of the proposed model. The effects of gas demand uncertainties on the optimal schedule of thermal generators are investigated as well.展开更多
Summary What is already known about this topic?Proficiency testing(PT)is a key component of qualityassurance and is essential in ensuring accuratelaboratory diagnosis of tuberculosis(TB)and drug-resistant TB.The Natio...Summary What is already known about this topic?Proficiency testing(PT)is a key component of qualityassurance and is essential in ensuring accuratelaboratory diagnosis of tuberculosis(TB)and drug-resistant TB.The National Tuberculosis ReferenceLaboratory(NTRL)developed a novel PT panel to testlaboratories’proficiency for molecular TB diagnosticassays throughout the TB laboratory network.A totalof 6 PT rounds for molecular diagnostics wereconducted by NTRL from 2014 to 2019.展开更多
The gas-fired generation has recently become an important power source for power systems.The increasing integration of gas-fired units(GFUs)brings a problem of location allocation strategy for power system planners.Th...The gas-fired generation has recently become an important power source for power systems.The increasing integration of gas-fired units(GFUs)brings a problem of location allocation strategy for power system planners.This paper proposes a bi-level maximum-minimum optimal placement model of GFUs to improve the static voltage stability in the transmission network.In the first stage,the locations of installed GFUs are optimized to improve the static voltage stability margin.The optimal installed capacity of GFUs is determined to minimize the operation costs and power losses in the second stage.The proposed mixed-integer nonlinear programming(MINLP)model is solved by second-order cone programming relaxations.Numerical results in the IEEE 118-bus test system demonstrate the effectiveness of the proposed method and the static voltage stability can be improved.展开更多
文摘A unified optimal power flow(OPF) model for AC/DC grids integrated with natural gas systems is proposed for the real-time scheduling of power systems.Herein, the primary physical couplings underlying this coordinated system are modeled and investigated. In addition, the uncertainties of gas loads are considered when studying the role of gas supply for gas-fired units in power system operations. The nonlinear gas system constraints are converted to the second-order cone forms that allow for the use of the Benders decomposition techniques and the interior-point method to obtain the optimal solution. The numerical results of the modified IEEE 118-bus test system that integrates the Belgium 20-node natural gas system demonstrate the effectiveness of the proposed model. The effects of gas demand uncertainties on the optimal schedule of thermal generators are investigated as well.
文摘Summary What is already known about this topic?Proficiency testing(PT)is a key component of qualityassurance and is essential in ensuring accuratelaboratory diagnosis of tuberculosis(TB)and drug-resistant TB.The National Tuberculosis ReferenceLaboratory(NTRL)developed a novel PT panel to testlaboratories’proficiency for molecular TB diagnosticassays throughout the TB laboratory network.A totalof 6 PT rounds for molecular diagnostics wereconducted by NTRL from 2014 to 2019.
文摘The gas-fired generation has recently become an important power source for power systems.The increasing integration of gas-fired units(GFUs)brings a problem of location allocation strategy for power system planners.This paper proposes a bi-level maximum-minimum optimal placement model of GFUs to improve the static voltage stability in the transmission network.In the first stage,the locations of installed GFUs are optimized to improve the static voltage stability margin.The optimal installed capacity of GFUs is determined to minimize the operation costs and power losses in the second stage.The proposed mixed-integer nonlinear programming(MINLP)model is solved by second-order cone programming relaxations.Numerical results in the IEEE 118-bus test system demonstrate the effectiveness of the proposed method and the static voltage stability can be improved.
