The features of three modes of AT-fed traction power networks (TPNs) have been briefly described in the existing literature, which is not adequate yet. In this paper, these three modes of TPNs are compared mainly on T...The features of three modes of AT-fed traction power networks (TPNs) have been briefly described in the existing literature, which is not adequate yet. In this paper, these three modes of TPNs are compared mainly on TPN capacity, transformer capacity, rail potential and voltage level, etc., and conclusions are drawn.展开更多
The worldwide demand for portable water is steadily growing due to population, industrial and agricultural growth, the result is water shortages that are already reaching serious proportions in many parts of the world...The worldwide demand for portable water is steadily growing due to population, industrial and agricultural growth, the result is water shortages that are already reaching serious proportions in many parts of the world. This is particularly true in Ghana where there is an increasing reliance on bottled water due to shortage of safe, fresh drinking water. Nuclear and conventional co-production of electricity and portable water has been identified as key solution to the perennial water shortages in coastal towns in Ghana. A reliable desalination cost date catering for site-specific condition in Ghana is required for policy makers, planners, consultants, process engineers, plant suppliers and researchers. This present paper is aims comparing the cost of co-production of power and portable water using reverse osmosis (RO) plant coupled with both nuclear and fossil power plant operating under different cycles using the desalination economic evaluation programme (DEEP4.0) developed by the international atomic energy agency (IAEA). The study concentrates on conditions of seawater in Accra, Ghana. Results show that co-production nuclear power plant operating on steam cycle can be the most economic among a number of power-water production options.展开更多
As the appearance of local dimming technique, the current existing test methods are not suitable for testing the power consumption of the LCD TVs using the local dimming technique any longer. A test method appropriate...As the appearance of local dimming technique, the current existing test methods are not suitable for testing the power consumption of the LCD TVs using the local dimming technique any longer. A test method appropriate to LED backlight LCD TVs using the local dimming technique is proposed in this paper, and then the test software is developed. The results demonstrate that the test software developed can show the real average power consumption of the LCD using local dimming technique, and by normalization the power consumption become comparable for not only local dimming LCD TVs but global dimming LCD TVs. Using the software developed in this paper, the ratio of power saving is clear when an LCD TV using the local dimming technique compared with one without local dimming technique.展开更多
In the future, solar energy will be a very important energy source. Several studies suppose that more than 45% of the energy in the world will be generated by photovoltaic array. Therefore it is necessary to concentra...In the future, solar energy will be a very important energy source. Several studies suppose that more than 45% of the energy in the world will be generated by photovoltaic array. Therefore it is necessary to concentrate our forces to reduce the application costs and to increment their performance. In order to reach the last aspect, it is important to note that the output characteristic of a photovoltaic array is nonlinear and changes with solar irradiation and cell’s temperature. Therefore a Maximum Power Point Tracking (MPPT) technique is needed to maximize the produced energy. This paper presents a comparative study of seven widely-adopted MPPT algorithms;their performance is evaluated using, for all the techniques, a common device with minimum hardware variations. In particular, this study compares the behaviors of each technique in presence of solar irradiation variations.展开更多
With the development of new energy technology, there are increasing applications of grid-connected photovoltaic power generation system. However, there is little research on development of electromechanical model of l...With the development of new energy technology, there are increasing applications of grid-connected photovoltaic power generation system. However, there is little research on development of electromechanical model of large scale photovoltaic power station. The computational speed will be very slow if electromagnetic transient model is used for stability study because of its complexity. Therefore, study on electromechanical transient model of grid-connected photovoltaic power generation system is of great meaning. In this paper, electromagnetic transient model of photovoltaic power generation system is introduced first, and then a general electromechanical transient model is proposed. These two kinds of simulation model are set up in PSCAD. By comparing the simulation results of two models, the correctness and validity of the electromechanical transient model is verified. It provides reference model for efficient simulation and modeling of grid-connected photovoltaic power station in large-scale power systems.展开更多
文摘The features of three modes of AT-fed traction power networks (TPNs) have been briefly described in the existing literature, which is not adequate yet. In this paper, these three modes of TPNs are compared mainly on TPN capacity, transformer capacity, rail potential and voltage level, etc., and conclusions are drawn.
文摘The worldwide demand for portable water is steadily growing due to population, industrial and agricultural growth, the result is water shortages that are already reaching serious proportions in many parts of the world. This is particularly true in Ghana where there is an increasing reliance on bottled water due to shortage of safe, fresh drinking water. Nuclear and conventional co-production of electricity and portable water has been identified as key solution to the perennial water shortages in coastal towns in Ghana. A reliable desalination cost date catering for site-specific condition in Ghana is required for policy makers, planners, consultants, process engineers, plant suppliers and researchers. This present paper is aims comparing the cost of co-production of power and portable water using reverse osmosis (RO) plant coupled with both nuclear and fossil power plant operating under different cycles using the desalination economic evaluation programme (DEEP4.0) developed by the international atomic energy agency (IAEA). The study concentrates on conditions of seawater in Accra, Ghana. Results show that co-production nuclear power plant operating on steam cycle can be the most economic among a number of power-water production options.
基金Project supported by the National Natural Science Foundation of China(Grant No.60871030)the Shanghai Leading Academic Discipline Project(Grant No.S30108)
文摘As the appearance of local dimming technique, the current existing test methods are not suitable for testing the power consumption of the LCD TVs using the local dimming technique any longer. A test method appropriate to LED backlight LCD TVs using the local dimming technique is proposed in this paper, and then the test software is developed. The results demonstrate that the test software developed can show the real average power consumption of the LCD using local dimming technique, and by normalization the power consumption become comparable for not only local dimming LCD TVs but global dimming LCD TVs. Using the software developed in this paper, the ratio of power saving is clear when an LCD TV using the local dimming technique compared with one without local dimming technique.
文摘In the future, solar energy will be a very important energy source. Several studies suppose that more than 45% of the energy in the world will be generated by photovoltaic array. Therefore it is necessary to concentrate our forces to reduce the application costs and to increment their performance. In order to reach the last aspect, it is important to note that the output characteristic of a photovoltaic array is nonlinear and changes with solar irradiation and cell’s temperature. Therefore a Maximum Power Point Tracking (MPPT) technique is needed to maximize the produced energy. This paper presents a comparative study of seven widely-adopted MPPT algorithms;their performance is evaluated using, for all the techniques, a common device with minimum hardware variations. In particular, this study compares the behaviors of each technique in presence of solar irradiation variations.
文摘With the development of new energy technology, there are increasing applications of grid-connected photovoltaic power generation system. However, there is little research on development of electromechanical model of large scale photovoltaic power station. The computational speed will be very slow if electromagnetic transient model is used for stability study because of its complexity. Therefore, study on electromechanical transient model of grid-connected photovoltaic power generation system is of great meaning. In this paper, electromagnetic transient model of photovoltaic power generation system is introduced first, and then a general electromechanical transient model is proposed. These two kinds of simulation model are set up in PSCAD. By comparing the simulation results of two models, the correctness and validity of the electromechanical transient model is verified. It provides reference model for efficient simulation and modeling of grid-connected photovoltaic power station in large-scale power systems.