To simulate the process of electrode operation, a dynamic model describing the electrode system of three-phase electric arc furnace was developed. This new model can be divided into three submodels in terms of the pra...To simulate the process of electrode operation, a dynamic model describing the electrode system of three-phase electric arc furnace was developed. This new model can be divided into three submodels in terms of the practical situation. They are the power supply system model the electric arc model and the hydraulic actuator system model. According to the basic circuit theory, the power supply system model where the high voltage transmission circuit and mutual inductances were considered, was set up. The electric arc model, which was novel for the electrode control, served as the electrical load and was connected to the power supply system model. The hydraulic actuator system model consists of the proportional valve part that is modeled to capture the dead-zone nonlinear characteristics and the hydraulic cylinder part where the impact of the load force is taken into account. By comparing simulation data and actual data, the results show that the electrode system model is proved to be accurate.展开更多
This paper investigates the performance of SAPFs （shunt active power filters） which are introduced in order to address the quality issues in electrified railway supply systems. These filters can be installed at eith...This paper investigates the performance of SAPFs （shunt active power filters） which are introduced in order to address the quality issues in electrified railway supply systems. These filters can be installed at either the S/S （substation） end or at the SP （sectioning post） of the railway feeding power system. In this investigation novel control algorithms, based on the synchronously rotating frame of reference, are proposed for the case when the SAPF is installed at the substation end and its performance is assessed. The effectiveness of the proposed control algorithms are illustrated via Matlab/SimPower computer simulations and validated via comparisons with other publications. This investigation demonstrated that when the SAPF is installed at the substation side, it can effectively compensate for the higher harmonic supply current. In addition, the reactive power demand is fully compensated for, leading to close to unity power factor. However, the voltage drop/sag at the locomotive power supply feed point is only partially compensated for.展开更多
The national energy supplier （Eskom in South Africa） supplies electricity through thousands-of-kilometers of overhead power lines. The current methods of inspection of these overhead power lines are infrequent and e...The national energy supplier （Eskom in South Africa） supplies electricity through thousands-of-kilometers of overhead power lines. The current methods of inspection of these overhead power lines are infrequent and expensive. In this paper, the authors present the development of a prototype monitoring system for power line inspection in South Africa. The developed prototype monitoring system collects data （information） from the overhead power lines, is remotely accessible and fits into a power line robot. The prototype monitoring system makes use ofa PandaBoard （SBC） with GPS receiver and 5 MP camera to collect data. Hardware fatigue is the biggest problem faced on the overhead power lines and is captured by means of the 5 MP camera and is displayed on a website hosted by the PandaBoard via Wi-Fi. The monitoring system has low power consumption, is light weight, compact and easily collects data. The data obtained from the prototype monitoring system was satisfactory and provides an improved solution for monitoring power lines for Eskom in South Africa.展开更多
基金Projects(2007AA04Z194, 2007AA041401) supported by the National High-Tech Research and Development Program of China
文摘To simulate the process of electrode operation, a dynamic model describing the electrode system of three-phase electric arc furnace was developed. This new model can be divided into three submodels in terms of the practical situation. They are the power supply system model the electric arc model and the hydraulic actuator system model. According to the basic circuit theory, the power supply system model where the high voltage transmission circuit and mutual inductances were considered, was set up. The electric arc model, which was novel for the electrode control, served as the electrical load and was connected to the power supply system model. The hydraulic actuator system model consists of the proportional valve part that is modeled to capture the dead-zone nonlinear characteristics and the hydraulic cylinder part where the impact of the load force is taken into account. By comparing simulation data and actual data, the results show that the electrode system model is proved to be accurate.
文摘This paper investigates the performance of SAPFs （shunt active power filters） which are introduced in order to address the quality issues in electrified railway supply systems. These filters can be installed at either the S/S （substation） end or at the SP （sectioning post） of the railway feeding power system. In this investigation novel control algorithms, based on the synchronously rotating frame of reference, are proposed for the case when the SAPF is installed at the substation end and its performance is assessed. The effectiveness of the proposed control algorithms are illustrated via Matlab/SimPower computer simulations and validated via comparisons with other publications. This investigation demonstrated that when the SAPF is installed at the substation side, it can effectively compensate for the higher harmonic supply current. In addition, the reactive power demand is fully compensated for, leading to close to unity power factor. However, the voltage drop/sag at the locomotive power supply feed point is only partially compensated for.
文摘The national energy supplier （Eskom in South Africa） supplies electricity through thousands-of-kilometers of overhead power lines. The current methods of inspection of these overhead power lines are infrequent and expensive. In this paper, the authors present the development of a prototype monitoring system for power line inspection in South Africa. The developed prototype monitoring system collects data （information） from the overhead power lines, is remotely accessible and fits into a power line robot. The prototype monitoring system makes use ofa PandaBoard （SBC） with GPS receiver and 5 MP camera to collect data. Hardware fatigue is the biggest problem faced on the overhead power lines and is captured by means of the 5 MP camera and is displayed on a website hosted by the PandaBoard via Wi-Fi. The monitoring system has low power consumption, is light weight, compact and easily collects data. The data obtained from the prototype monitoring system was satisfactory and provides an improved solution for monitoring power lines for Eskom in South Africa.
