Most of the photo voltaic (PV) arrays often work in harsh outdoor environment, and undergo various faults, such as local material aging, shading, open circuit, short circuit and so on. The generation of these faults w...Most of the photo voltaic (PV) arrays often work in harsh outdoor environment, and undergo various faults, such as local material aging, shading, open circuit, short circuit and so on. The generation of these faults will reduce the power generation efficiency, and when a fault occurs in a PV model, the PV model and the systems connected to it are also damaged. In this paper, an on-line distributed monitoring system based on XBee wireless sensors network is designed to monitor the output current, voltage and irradiation of each PV module, and the temperature and the irradiation of the environment. A simulation PV module model is established, based on which some common faults are simulated and fault training samples are obtained. Finally, a memetic algorithm optimized Back Propagation ANN fault diagnosis model is built and trained by the fault samples data. Experiment result shows that the system can detect the common faults of PV array with high accuracy.展开更多
Unregulated utilization of renewable generation including residential photovoltaic (PV) systems can have a significant impact on load characteristics in distribution networks. For improving PV generation capabilities,...Unregulated utilization of renewable generation including residential photovoltaic (PV) systems can have a significant impact on load characteristics in distribution networks. For improving PV generation capabilities, power quality aspects have to be coordinated with present load characteristics. This paper discusses the harmonic content of PV generation and the influence to power quality indicators in residential distribution networks. PV generation measurement results including current harmonic amplitude and phase angle values are presented. Results of different modelling scenarios are analysed and a simplified model of harmonics in PVs is offered. The results of the study showed a moderate additional harmonic distortion in residential load current and voltage distortion at the substation’s busbar when PVs were added. Novelty of the paper is that harmonic current values at higher orders are presented and analysed. The results pointed out in this paper could be further used for modelling the actual harmonic loads of the PVs in distribution networks.展开更多
The high utilization level of renewable generation including residential photovoltaic (PV) systems together with the uncontrolled charging of electric vehicles (EVs) can have a significant impact on load characteristi...The high utilization level of renewable generation including residential photovoltaic (PV) systems together with the uncontrolled charging of electric vehicles (EVs) can have a significant impact on load characteristics in distribution networks. Harmonic content of PV generation, EV charging loads, and their influence on power quality indicators in residential distribution networks are discussed in this paper. For investigating likely power quality scenarios, PV generation and EV charging measurement results including current harmonic amplitude and phase angle values are used and compared with present load characteristics. Different modelling scenarios are analysed and a simplified model of harmonics in PVs and EVs is offered. The results of the study show moderate additional harmonic distortion in residential load current and voltage distortion at the substation’s busbar when PV generation and EV loading are added. The scenarios presented in this paper can be further used for modelling the actual harmonic loads of the PVs and EVs in distribution networks.展开更多
The rising of the world’s population leads automatically to the rising of water demand. As a consequence the lack of drinking water increases. Currently, approximately 1.2 billion people globally (one-sixth of the wo...The rising of the world’s population leads automatically to the rising of water demand. As a consequence the lack of drinking water increases. Currently, approximately 1.2 billion people globally (one-sixth of the world’s population) do not have access to adequate clean water. Since a large part of the world’s population is concentrated in coastal areas, the desalination of seawater seems to be a promising solution, especially in our Arab world. An innovative stand-alone solar desalination system could be used to produce drinking water from seawater or any brackish water sources. The great advantage of such a system is that it combines efficient desalination technology, reverse osmosis, with a renewable energy source;the main goal is improving the technical feasibility of such systems. There are many advantages of this coupling with RE resources;first of all we separate the drinking water from the electricity grid and its faults, save the burning fossil fuel and its emissions and can provide fresh water to remote communities that do not have sufficient traditional energy sources;but as we see in the thesis we don’t have economic benefit;because these projects depend on the electricity cost in each country and its location and its solar specifications. We design and implement a small laboratorial model for PV-RO (Photo-Voltaic Powered Reverse Osmosis) to recognize the its performance for seawater and brackish water;many of the problems are interrupted such as embargo on Syria;so we see this project has to be done according to affordable local potentialities, but we crave to keep the principle of operation, so we make it for the tap water which close to brackish.展开更多
The Ce-Co-doped BiFeO3 multiferroic, Bi（1-x）Ce）xFe（1-x）CoxO3（x = 0.00, 0.01, 0.03, and 0.05）, has been prepared by a sol-gel auto-combustion method and analyzed through Raman spectroscopy, photoluminescence, an...The Ce-Co-doped BiFeO3 multiferroic, Bi（1-x）Ce）xFe（1-x）CoxO3（x = 0.00, 0.01, 0.03, and 0.05）, has been prepared by a sol-gel auto-combustion method and analyzed through Raman spectroscopy, photoluminescence, and UV-visible spectroscopy. We have observed an anomalous intensity of the second-order Raman mode at - 1260 cm^-1 in pure BFO and suppressed intensity in doped samples, which indicates the presence of spin two-phonon coupling in these samples.The photoluminescence spectra show reduction in the intensity of emission with the increasing dopant concentration, which indicates the high charge separation efficiency. A sharp absorption with three charge transfer（C-T） and two d-d transitions are shown by UV-visible spectra in the visible region. The band gap of BiFeO3（BFO） is decreasing with increasing dopant concentrations and the materials are suitable for photovoltaic applications.展开更多
Extraction of accurate Photo Voltaic (PV) model parameters is a challenging task for PV simulator developers. To mitigate this challenging task a novel approach using Gravitational Search Algorithm (GSA) for accurate ...Extraction of accurate Photo Voltaic (PV) model parameters is a challenging task for PV simulator developers. To mitigate this challenging task a novel approach using Gravitational Search Algorithm (GSA) for accurate extraction of PV model parameters is proposed in this paper. GSA is a population based heuristic optimization method which depends on the law of gravity and mass interactions. In this optimization method, the searcher agents are collection of masses which interact with each other using laws of gravity and motion of Newton. The developed PV model utilizes mathematical equations and is described through an equivalent circuit model comprising of a current source, a diode, a series resistor and a shunt resistor including the effect of changes in solar irradiation and ambient temperature. The optimal values of photo-current, diode ideality factor, series resistance and shunt resistance of the developed PV model are obtained by using GSA. The simulations of the characteristic curves of PV modules (SM55, ST36 and ST40) are carried out using MATLAB/Simulink environment. Results obtained using GSA are compared with Differential Evolution (DE), which shows that GSA based parameters are better optimal when compared to DE.展开更多
In India most part receives 4 - 7 kWh of solar radiation per square meter per day with 200 - 250 sunny days in a year. Tamilnadu state also receives the highest annual radiation in India. In this paper, the grid conne...In India most part receives 4 - 7 kWh of solar radiation per square meter per day with 200 - 250 sunny days in a year. Tamilnadu state also receives the highest annual radiation in India. In this paper, the grid connected photovoltaic plant has a peak power of 80 KWp supplies electricity requirement of GRT IET campus during day time (7 hrs) and reduces load demand and generates useful data for future implementation of such PV plant projects in the Tamilnadu region. Photovoltaic plant was installed in April 2015, monitored during 6 months, and the performance ratio and the various power losses (power electronics, temperature, soiling, internal, network, grid availability and interconnection) were calculated. The PV plant supplied 64,182.86 KWh to the grid from April to September 2015, ranging from 11,510.900 to 10,200.9 kWh. The final yield ranged from 143.886 (h/d) to 127.51 (y/d), reference yield ranged from 201.6 (h/d) to 155.31 (h/d) and performance ratio ranged from 71.3% to 82.1%, for a duration of six months, it had given a performance ratio of 83.82%, system efficiency was 4.16% and the capacity factor of GRT IET Campus for six months was 18.26%. Payback period in years = 9 years 4 months, energy saving per year = 204,400 KWh, cost reduction per year = 1,737,400, Indian rupee = 26,197.30 USD and total CO<sub>2</sub> reductions per year = 102,200 tons CO<sub>2</sub>/year.展开更多
This research paper proposes a single phase fifteen level inverter for a grid connected PV system.The proposed inverter is also called cascaded asymmetric multilevel inverter.By adopting appropriate hybrid modulation ...This research paper proposes a single phase fifteen level inverter for a grid connected PV system.The proposed inverter is also called cascaded asymmetric multilevel inverter.By adopting appropriate hybrid modulation technique improved output voltage is obtained with minimum number of power electronic switches.By reducing the number of gate triggering circuits of the switches,the size and power consumption of the driving circuits can be reduced.The total harmonic distortion of the output of the inverter is improved by this inverter.The proposed inverter developed by cascading a full bridge inverter with modified H bridge multilevel inverter.The validity of the proposed system is verified through MATLAB simulations.展开更多
The energy efficient product can be operated with longer duration.They offer wonderful solutions compared to other conventional water pumping system as it needs less maintenance,simple in installation,zero fuel cost,l...The energy efficient product can be operated with longer duration.They offer wonderful solutions compared to other conventional water pumping system as it needs less maintenance,simple in installation,zero fuel cost,longer operating life,highly reliable and free from production of greenhouse gases.In this paper we analyzed the different topologies of DC–DC converter in terms of their operating region of MPPT,quality of input and output currents.We discussed the MPPT algorithms to address partial shading effects in SPV array,present state of the technology,factors affecting the performance of the system,efficiency improvements and identified the research gaps.Also,the economic feasibility analysis has been done for the real time scenario using the Homer Pro software.The estimation of total dynamic head and horse power calculation has been done to decide the total load capacity.The economic analysis results such as cumulative cash flow over project lifetime of 25 years are presented.It is observed that the capital investment requirement is$7,425 for installing Fronius PV system that has a nominal capacity of 2.47 kW and annualized savings will be$134.93.In the long-term perspective,the return on investment is−2.18%as per the present tariff plan.展开更多
文摘Most of the photo voltaic (PV) arrays often work in harsh outdoor environment, and undergo various faults, such as local material aging, shading, open circuit, short circuit and so on. The generation of these faults will reduce the power generation efficiency, and when a fault occurs in a PV model, the PV model and the systems connected to it are also damaged. In this paper, an on-line distributed monitoring system based on XBee wireless sensors network is designed to monitor the output current, voltage and irradiation of each PV module, and the temperature and the irradiation of the environment. A simulation PV module model is established, based on which some common faults are simulated and fault training samples are obtained. Finally, a memetic algorithm optimized Back Propagation ANN fault diagnosis model is built and trained by the fault samples data. Experiment result shows that the system can detect the common faults of PV array with high accuracy.
文摘Unregulated utilization of renewable generation including residential photovoltaic (PV) systems can have a significant impact on load characteristics in distribution networks. For improving PV generation capabilities, power quality aspects have to be coordinated with present load characteristics. This paper discusses the harmonic content of PV generation and the influence to power quality indicators in residential distribution networks. PV generation measurement results including current harmonic amplitude and phase angle values are presented. Results of different modelling scenarios are analysed and a simplified model of harmonics in PVs is offered. The results of the study showed a moderate additional harmonic distortion in residential load current and voltage distortion at the substation’s busbar when PVs were added. Novelty of the paper is that harmonic current values at higher orders are presented and analysed. The results pointed out in this paper could be further used for modelling the actual harmonic loads of the PVs in distribution networks.
文摘The high utilization level of renewable generation including residential photovoltaic (PV) systems together with the uncontrolled charging of electric vehicles (EVs) can have a significant impact on load characteristics in distribution networks. Harmonic content of PV generation, EV charging loads, and their influence on power quality indicators in residential distribution networks are discussed in this paper. For investigating likely power quality scenarios, PV generation and EV charging measurement results including current harmonic amplitude and phase angle values are used and compared with present load characteristics. Different modelling scenarios are analysed and a simplified model of harmonics in PVs and EVs is offered. The results of the study show moderate additional harmonic distortion in residential load current and voltage distortion at the substation’s busbar when PV generation and EV loading are added. The scenarios presented in this paper can be further used for modelling the actual harmonic loads of the PVs and EVs in distribution networks.
文摘The rising of the world’s population leads automatically to the rising of water demand. As a consequence the lack of drinking water increases. Currently, approximately 1.2 billion people globally (one-sixth of the world’s population) do not have access to adequate clean water. Since a large part of the world’s population is concentrated in coastal areas, the desalination of seawater seems to be a promising solution, especially in our Arab world. An innovative stand-alone solar desalination system could be used to produce drinking water from seawater or any brackish water sources. The great advantage of such a system is that it combines efficient desalination technology, reverse osmosis, with a renewable energy source;the main goal is improving the technical feasibility of such systems. There are many advantages of this coupling with RE resources;first of all we separate the drinking water from the electricity grid and its faults, save the burning fossil fuel and its emissions and can provide fresh water to remote communities that do not have sufficient traditional energy sources;but as we see in the thesis we don’t have economic benefit;because these projects depend on the electricity cost in each country and its location and its solar specifications. We design and implement a small laboratorial model for PV-RO (Photo-Voltaic Powered Reverse Osmosis) to recognize the its performance for seawater and brackish water;many of the problems are interrupted such as embargo on Syria;so we see this project has to be done according to affordable local potentialities, but we crave to keep the principle of operation, so we make it for the tap water which close to brackish.
文摘The Ce-Co-doped BiFeO3 multiferroic, Bi（1-x）Ce）xFe（1-x）CoxO3（x = 0.00, 0.01, 0.03, and 0.05）, has been prepared by a sol-gel auto-combustion method and analyzed through Raman spectroscopy, photoluminescence, and UV-visible spectroscopy. We have observed an anomalous intensity of the second-order Raman mode at - 1260 cm^-1 in pure BFO and suppressed intensity in doped samples, which indicates the presence of spin two-phonon coupling in these samples.The photoluminescence spectra show reduction in the intensity of emission with the increasing dopant concentration, which indicates the high charge separation efficiency. A sharp absorption with three charge transfer（C-T） and two d-d transitions are shown by UV-visible spectra in the visible region. The band gap of BiFeO3（BFO） is decreasing with increasing dopant concentrations and the materials are suitable for photovoltaic applications.
文摘Extraction of accurate Photo Voltaic (PV) model parameters is a challenging task for PV simulator developers. To mitigate this challenging task a novel approach using Gravitational Search Algorithm (GSA) for accurate extraction of PV model parameters is proposed in this paper. GSA is a population based heuristic optimization method which depends on the law of gravity and mass interactions. In this optimization method, the searcher agents are collection of masses which interact with each other using laws of gravity and motion of Newton. The developed PV model utilizes mathematical equations and is described through an equivalent circuit model comprising of a current source, a diode, a series resistor and a shunt resistor including the effect of changes in solar irradiation and ambient temperature. The optimal values of photo-current, diode ideality factor, series resistance and shunt resistance of the developed PV model are obtained by using GSA. The simulations of the characteristic curves of PV modules (SM55, ST36 and ST40) are carried out using MATLAB/Simulink environment. Results obtained using GSA are compared with Differential Evolution (DE), which shows that GSA based parameters are better optimal when compared to DE.
文摘In India most part receives 4 - 7 kWh of solar radiation per square meter per day with 200 - 250 sunny days in a year. Tamilnadu state also receives the highest annual radiation in India. In this paper, the grid connected photovoltaic plant has a peak power of 80 KWp supplies electricity requirement of GRT IET campus during day time (7 hrs) and reduces load demand and generates useful data for future implementation of such PV plant projects in the Tamilnadu region. Photovoltaic plant was installed in April 2015, monitored during 6 months, and the performance ratio and the various power losses (power electronics, temperature, soiling, internal, network, grid availability and interconnection) were calculated. The PV plant supplied 64,182.86 KWh to the grid from April to September 2015, ranging from 11,510.900 to 10,200.9 kWh. The final yield ranged from 143.886 (h/d) to 127.51 (y/d), reference yield ranged from 201.6 (h/d) to 155.31 (h/d) and performance ratio ranged from 71.3% to 82.1%, for a duration of six months, it had given a performance ratio of 83.82%, system efficiency was 4.16% and the capacity factor of GRT IET Campus for six months was 18.26%. Payback period in years = 9 years 4 months, energy saving per year = 204,400 KWh, cost reduction per year = 1,737,400, Indian rupee = 26,197.30 USD and total CO<sub>2</sub> reductions per year = 102,200 tons CO<sub>2</sub>/year.
文摘This research paper proposes a single phase fifteen level inverter for a grid connected PV system.The proposed inverter is also called cascaded asymmetric multilevel inverter.By adopting appropriate hybrid modulation technique improved output voltage is obtained with minimum number of power electronic switches.By reducing the number of gate triggering circuits of the switches,the size and power consumption of the driving circuits can be reduced.The total harmonic distortion of the output of the inverter is improved by this inverter.The proposed inverter developed by cascading a full bridge inverter with modified H bridge multilevel inverter.The validity of the proposed system is verified through MATLAB simulations.
文摘The energy efficient product can be operated with longer duration.They offer wonderful solutions compared to other conventional water pumping system as it needs less maintenance,simple in installation,zero fuel cost,longer operating life,highly reliable and free from production of greenhouse gases.In this paper we analyzed the different topologies of DC–DC converter in terms of their operating region of MPPT,quality of input and output currents.We discussed the MPPT algorithms to address partial shading effects in SPV array,present state of the technology,factors affecting the performance of the system,efficiency improvements and identified the research gaps.Also,the economic feasibility analysis has been done for the real time scenario using the Homer Pro software.The estimation of total dynamic head and horse power calculation has been done to decide the total load capacity.The economic analysis results such as cumulative cash flow over project lifetime of 25 years are presented.It is observed that the capital investment requirement is$7,425 for installing Fronius PV system that has a nominal capacity of 2.47 kW and annualized savings will be$134.93.In the long-term perspective,the return on investment is−2.18%as per the present tariff plan.
