The operating efficiency of container shipping lines depends on proper resource allocation of container shipping.A deterministic model was developed for shipping lines based on the equilibrium principle.The objective ...The operating efficiency of container shipping lines depends on proper resource allocation of container shipping.A deterministic model was developed for shipping lines based on the equilibrium principle.The objective was to optimize the resource allocation for container lines considering ship size,container deployment,and slot allocation.The deterministic model was then expanded to a robust optimization model accounting for the uncertain factors,while ship size was treated as the design variable and slot allocation as the control variable.The effectiveness of the proposed model is demonstrated using a pendulum shipping line as an example.The results indicate that infeasible solutions will increase and the model robustness will be enhanced by an increased penalty coefficient and the solution robustness will be enhanced by increasing the preference coefficient.The optimization model simultaneously considers demand uncertainty,model robustness,and risk preference of the decision maker to agree better with actual practices.展开更多
The development of high-voltage direct current gas-insulated switchgear assemblies(DC GIS)of rated voltages up to±550 kV has been completed.DC GIS provide a compact technical solution with a high functional densi...The development of high-voltage direct current gas-insulated switchgear assemblies(DC GIS)of rated voltages up to±550 kV has been completed.DC GIS provide a compact technical solution with a high functional density,optimized for projects with limited space as in offshore HVDC converter platforms,onshore HVDC converter stations and transition stations between different transmission media.Up to now,no standards for testing of gas-insulated DC systems are available,although pre-standardization work is in progress within CIGRE.Some tests can be performed as required in AC GIS standards.Special aspects of DC voltage stress,like the electric field distribution of insulators influenced by the accumulation of electrical charge carriers and the operation-related inhomogeneous temperature distribution,must be considered by additional electric and thermoelectric tests.For DC GIS,the experience of long-term performance is limited today.Although ageing is expected to be of lower importance,tests are recommended.This contribution summarizes the physical and technical background to design and develop compact DC switchgear assemblies using gas-insulated technology.It explains the developed modules of the substation and gives an overview of the performed tests.Furthermore,it provides an insight in the on-going standardization activities and describes applications in converter and transition stations,showing its space-saving characteristics.展开更多
基金Supported by the Specialized Research Fund for the Doctoral Program of Higher Education of MOE,PRC (No 20092125120001)
文摘The operating efficiency of container shipping lines depends on proper resource allocation of container shipping.A deterministic model was developed for shipping lines based on the equilibrium principle.The objective was to optimize the resource allocation for container lines considering ship size,container deployment,and slot allocation.The deterministic model was then expanded to a robust optimization model accounting for the uncertain factors,while ship size was treated as the design variable and slot allocation as the control variable.The effectiveness of the proposed model is demonstrated using a pendulum shipping line as an example.The results indicate that infeasible solutions will increase and the model robustness will be enhanced by an increased penalty coefficient and the solution robustness will be enhanced by increasing the preference coefficient.The optimization model simultaneously considers demand uncertainty,model robustness,and risk preference of the decision maker to agree better with actual practices.
基金supported by the Federal Ministry for Economic Affairs and Energy, Germany (FKZ:03ET7511C)the Bavarian Ministry of Economic Affairs, Regional Development and Energy (FKZ:IET-1208-0018)
文摘The development of high-voltage direct current gas-insulated switchgear assemblies(DC GIS)of rated voltages up to±550 kV has been completed.DC GIS provide a compact technical solution with a high functional density,optimized for projects with limited space as in offshore HVDC converter platforms,onshore HVDC converter stations and transition stations between different transmission media.Up to now,no standards for testing of gas-insulated DC systems are available,although pre-standardization work is in progress within CIGRE.Some tests can be performed as required in AC GIS standards.Special aspects of DC voltage stress,like the electric field distribution of insulators influenced by the accumulation of electrical charge carriers and the operation-related inhomogeneous temperature distribution,must be considered by additional electric and thermoelectric tests.For DC GIS,the experience of long-term performance is limited today.Although ageing is expected to be of lower importance,tests are recommended.This contribution summarizes the physical and technical background to design and develop compact DC switchgear assemblies using gas-insulated technology.It explains the developed modules of the substation and gives an overview of the performed tests.Furthermore,it provides an insight in the on-going standardization activities and describes applications in converter and transition stations,showing its space-saving characteristics.
