During faults in a distribution network,the output power of a distributed generation(DG)may be uncertain.Moreover,the output currents of distributed power sources are also affected by the output power,resulting in unc...During faults in a distribution network,the output power of a distributed generation(DG)may be uncertain.Moreover,the output currents of distributed power sources are also affected by the output power,resulting in uncertainties in the calculation of the short-circuit current at the time of a fault.Additionally,the impacts of such uncertainties around short-circuit currents will increase with the increase of distributed power sources.Thus,it is very important to develop a method for calculating the short-circuit current while considering the uncertainties in a distribution network.In this study,an affine arithmetic algorithm for calculating short-circuit current intervals in distribution networks with distributed power sources while considering power fluctuations is presented.The proposed algorithm includes two stages.In the first stage,normal operations are considered to establish a conservative interval affine optimization model of injection currents in distributed power sources.Constrained by the fluctuation range of distributed generation power at the moment of fault occurrence,the model can then be used to solve for the fluctuation range of injected current amplitudes in distributed power sources.The second stage is implemented after a malfunction occurs.In this stage,an affine optimization model is first established.This model is developed to characterizes the short-circuit current interval of a transmission line,and is constrained by the fluctuation range of the injected current amplitude of DG during normal operations.Finally,the range of the short-circuit current amplitudes of distribution network lines after a short-circuit fault occurs is predicted.The algorithm proposed in this article obtains an interval range containing accurate results through interval operation.Compared with traditional point value calculation methods,interval calculation methods can provide more reliable analysis and calculation results.The range of short-circuit current amplitude obtained by this algorithm is slightly larger than those obtained using the Monte Carlo algorithm and the Latin hypercube sampling algorithm.Therefore,the proposed algorithm has good suitability and does not require iterative calculations,resulting in a significant improvement in computational speed compared to the Monte Carlo algorithm and the Latin hypercube sampling algorithm.Furthermore,the proposed algorithm can provide more reliable analysis and calculation results,improving the safety and stability of power systems.展开更多
After entering the information-based society, profound reform has happened in the business pattern of enterprises, and thecompetitive mode between traditional enterprises has been transformed into the competition betw...After entering the information-based society, profound reform has happened in the business pattern of enterprises, and thecompetitive mode between traditional enterprises has been transformed into the competition between supply chains in nowadays. The liquorindustry in Luzhou is the pillar industry of economy, which involves “Luzhou Old Cellar”, “Ichiro Liquor”and other large-scale enterpriseswith well-known brands. Besides, many small and medium-sized enterprises are developing and flourishing in Luzhou. Compared with thedevelopment of large enterprises, the development of small and medium sized enterprises has more uncertainty and risks. At present, Luzhou Cityis setting about to build Huangyi into a liquor centralized zone, which is also a clusterization strategy for industry development of Luzhou liquor.For Luzhou Liquor Zone, the implementation of supply chain management of small and medium-sized enterprises can greatly reduce the cost ofenterprises and improve effi ciency of operation. The growth and development of small and medium-sized enterprises in Luzhou Liquor Zone andthe promotion of advantages of industrial clusters are closely related to the risks of the supply chain.展开更多
Hepatic hemangiomas(HHs)are the most common benign tumors of the liver.These tumors are mainly asymptomatic and do not require treatment.Nevertheless,there are some special cases that require therapeutic intervention,...Hepatic hemangiomas(HHs)are the most common benign tumors of the liver.These tumors are mainly asymptomatic and do not require treatment.Nevertheless,there are some special cases that require therapeutic intervention,and surgery and intervention are currently the primary treatment modalities.Despite significant advances in the development of minimally invasive techniques and their popularization,interventional treatment of HH is still the preferred choice.In the present review,we discuss the pathological properties,type of blood supply,and treatment indications for HH and assess the status and progress of the existing interventional treatments.展开更多
基金This article was supported by the general project“Research on Wind and Photovoltaic Fault Characteristics and Practical Short Circuit Calculation Model”(521820200097)of Jiangxi Electric Power Company.
文摘During faults in a distribution network,the output power of a distributed generation(DG)may be uncertain.Moreover,the output currents of distributed power sources are also affected by the output power,resulting in uncertainties in the calculation of the short-circuit current at the time of a fault.Additionally,the impacts of such uncertainties around short-circuit currents will increase with the increase of distributed power sources.Thus,it is very important to develop a method for calculating the short-circuit current while considering the uncertainties in a distribution network.In this study,an affine arithmetic algorithm for calculating short-circuit current intervals in distribution networks with distributed power sources while considering power fluctuations is presented.The proposed algorithm includes two stages.In the first stage,normal operations are considered to establish a conservative interval affine optimization model of injection currents in distributed power sources.Constrained by the fluctuation range of distributed generation power at the moment of fault occurrence,the model can then be used to solve for the fluctuation range of injected current amplitudes in distributed power sources.The second stage is implemented after a malfunction occurs.In this stage,an affine optimization model is first established.This model is developed to characterizes the short-circuit current interval of a transmission line,and is constrained by the fluctuation range of the injected current amplitude of DG during normal operations.Finally,the range of the short-circuit current amplitudes of distribution network lines after a short-circuit fault occurs is predicted.The algorithm proposed in this article obtains an interval range containing accurate results through interval operation.Compared with traditional point value calculation methods,interval calculation methods can provide more reliable analysis and calculation results.The range of short-circuit current amplitude obtained by this algorithm is slightly larger than those obtained using the Monte Carlo algorithm and the Latin hypercube sampling algorithm.Therefore,the proposed algorithm has good suitability and does not require iterative calculations,resulting in a significant improvement in computational speed compared to the Monte Carlo algorithm and the Latin hypercube sampling algorithm.Furthermore,the proposed algorithm can provide more reliable analysis and calculation results,improving the safety and stability of power systems.
文摘After entering the information-based society, profound reform has happened in the business pattern of enterprises, and thecompetitive mode between traditional enterprises has been transformed into the competition between supply chains in nowadays. The liquorindustry in Luzhou is the pillar industry of economy, which involves “Luzhou Old Cellar”, “Ichiro Liquor”and other large-scale enterpriseswith well-known brands. Besides, many small and medium-sized enterprises are developing and flourishing in Luzhou. Compared with thedevelopment of large enterprises, the development of small and medium sized enterprises has more uncertainty and risks. At present, Luzhou Cityis setting about to build Huangyi into a liquor centralized zone, which is also a clusterization strategy for industry development of Luzhou liquor.For Luzhou Liquor Zone, the implementation of supply chain management of small and medium-sized enterprises can greatly reduce the cost ofenterprises and improve effi ciency of operation. The growth and development of small and medium-sized enterprises in Luzhou Liquor Zone andthe promotion of advantages of industrial clusters are closely related to the risks of the supply chain.
文摘Hepatic hemangiomas(HHs)are the most common benign tumors of the liver.These tumors are mainly asymptomatic and do not require treatment.Nevertheless,there are some special cases that require therapeutic intervention,and surgery and intervention are currently the primary treatment modalities.Despite significant advances in the development of minimally invasive techniques and their popularization,interventional treatment of HH is still the preferred choice.In the present review,we discuss the pathological properties,type of blood supply,and treatment indications for HH and assess the status and progress of the existing interventional treatments.
