T. Lemes, Lapec, Rs. Brazil, Sherdil Khan, E. L. Silva, L. L. Costa, S. Teixeira, C. Aguzzoli, C. Malfatti
To improve light absorption in the visible region and to improve photoelectrochemical (PEC) response; herein, we have presented the doping of titanium dioxide (TiO2) nanotubes with nitrogen. TiO2 nanotubes have been heat treated under the ammonia environment at different temperatures for 3 h. The characterization was carried out using field emission gun scanning electron microscopy, (FEG-SEM), visible ultraviolet (UV-Vis) spectrophotometry. The photoelectrochemical tests of the samples were carried out in a Na2S/Na2SO3 (aq) solution. It was found that the nitrogen doping of titanium dioxide in temperature above 600 °C collapses the tubular structure and decreases the PEC performance. On the other hand, PEC performance improving was obtained from the sample nitrided at the lower temperatura which is related to the formation of lower defects in the structure of TiO2 nanotubes.
{"title":"Effect of nitridation temperature on TiO2 nanotubular structure and its photoelectrochemical performance","authors":"T. Lemes, Lapec, Rs. Brazil, Sherdil Khan, E. L. Silva, L. L. Costa, S. Teixeira, C. Aguzzoli, C. Malfatti","doi":"10.24084/repqj16.466","DOIUrl":"https://doi.org/10.24084/repqj16.466","url":null,"abstract":"To improve light absorption in the visible region and to improve photoelectrochemical (PEC) response; herein, we have presented the doping of titanium dioxide (TiO2) nanotubes with nitrogen. TiO2 nanotubes have been heat treated under the ammonia environment at different temperatures for 3 h. The characterization was carried out using field emission gun scanning electron microscopy, (FEG-SEM), visible ultraviolet (UV-Vis) spectrophotometry. The photoelectrochemical tests of the samples were carried out in a Na2S/Na2SO3 (aq) solution. It was found that the nitrogen doping of titanium dioxide in temperature above 600 °C collapses the tubular structure and decreases the PEC performance. On the other hand, PEC performance improving was obtained from the sample nitrided at the lower temperatura which is related to the formation of lower defects in the structure of TiO2 nanotubes.","PeriodicalId":21007,"journal":{"name":"Renewable energy & power quality journal","volume":"45 1","pages":"778-781"},"PeriodicalIF":0.0,"publicationDate":"2018-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79337242","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
E. Cornalino, Administración del Mercado Eléctrico . Uruguay, R. Chaer
The aim of this research is to improve the capacity to represent and forecast the electric demand for next week’s scheduling. Currently the demand forecast used for this purpose is deterministic, which is not representative of reality, even if an ideal temperature forecast was available. The current context of the Uruguayan electrical system has high probability of exportable surplus energy. For this reason, improvements to the procedure used to calculate systems supply costs and the quantity of exportable energy are welcome, in order to maximize the benefit we can get from resources. The methodology applied is based on previous developments for simulation of stochastic variables within the SimSEE platform [2]. It combines daily step CEGH model [3] with a k-means clustering method [4]. Obtained results were satisfactory both from the point of view of the representation of the temporal behavior of the power demand, and from the point of view of the error obtained in the predictions. What is more, this improvements helps to reduce risks involved when making energy commitments with neighbouring countries.
{"title":"Probabilistic Electric Load Forecasting Model for the Uruguayan Interconnected Electrical System","authors":"E. Cornalino, Administración del Mercado Eléctrico . Uruguay, R. Chaer","doi":"10.24084/repqj16.255","DOIUrl":"https://doi.org/10.24084/repqj16.255","url":null,"abstract":"The aim of this research is to improve the capacity to represent and forecast the electric demand for next week’s scheduling. Currently the demand forecast used for this purpose is deterministic, which is not representative of reality, even if an ideal temperature forecast was available. The current context of the Uruguayan electrical system has high probability of exportable surplus energy. For this reason, improvements to the procedure used to calculate systems supply costs and the quantity of exportable energy are welcome, in order to maximize the benefit we can get from resources. The methodology applied is based on previous developments for simulation of stochastic variables within the SimSEE platform [2]. It combines daily step CEGH model [3] with a k-means clustering method [4]. Obtained results were satisfactory both from the point of view of the representation of the temporal behavior of the power demand, and from the point of view of the error obtained in the predictions. What is more, this improvements helps to reduce risks involved when making energy commitments with neighbouring countries.","PeriodicalId":21007,"journal":{"name":"Renewable energy & power quality journal","volume":"6 1","pages":"181-186"},"PeriodicalIF":0.0,"publicationDate":"2018-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81851938","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. Roque, V. Pires, L. Pedraza, E. Margato, D. Sousa
{"title":"Modeling and Control of a DC Supply System for Electrical Vehicle Charging Based on Renewable Energy Sources with the Support of Storage","authors":"A. Roque, V. Pires, L. Pedraza, E. Margato, D. Sousa","doi":"10.24084/REPQJ16.444","DOIUrl":"https://doi.org/10.24084/REPQJ16.444","url":null,"abstract":"","PeriodicalId":21007,"journal":{"name":"Renewable energy & power quality journal","volume":"59 1","pages":"722-727"},"PeriodicalIF":0.0,"publicationDate":"2018-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83713030","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
S. Sánchez-Orgaz, Etsi Industriales-Universidad Politécnica de Madrid. Spain, J. R. Martín, Á. J. Alvaro, I. Paniagua, C. G. Fernandez, R. N. Carlier
{"title":"Influence of the compression pressure ratio on the energetic and exergetic efficiency of a solar driven regenerative closed Brayton cycle with helium as working fluid","authors":"S. Sánchez-Orgaz, Etsi Industriales-Universidad Politécnica de Madrid. Spain, J. R. Martín, Á. J. Alvaro, I. Paniagua, C. G. Fernandez, R. N. Carlier","doi":"10.24084/REPQJ16.378","DOIUrl":"https://doi.org/10.24084/REPQJ16.378","url":null,"abstract":"","PeriodicalId":21007,"journal":{"name":"Renewable energy & power quality journal","volume":"1 1","pages":"533-537"},"PeriodicalIF":0.0,"publicationDate":"2018-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81304287","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jesús Javier Losada Maseda, A. F. Vizoso, E. M. Camacho, Laura Castro Santos, Francisco Javier López Montero
{"title":"Integration of maintainability and operativity criteria in the contracts to build under EPC model in energy infrastructures to optimize the OPEX. Example of the methodology to analyse the preferences in the owner and contractor point of view","authors":"Jesús Javier Losada Maseda, A. F. Vizoso, E. M. Camacho, Laura Castro Santos, Francisco Javier López Montero","doi":"10.24084/repqj16.450","DOIUrl":"https://doi.org/10.24084/repqj16.450","url":null,"abstract":"","PeriodicalId":21007,"journal":{"name":"Renewable energy & power quality journal","volume":"41 1","pages":"435-440"},"PeriodicalIF":0.0,"publicationDate":"2018-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82771208","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Christian Waniek, T. Wohlfahrt, J. Myrzik, Jan Meyer, P. Schegner
{"title":"Supraharmonic Interactions between Multiple Devices within Different Local Low Voltage Grid Structures","authors":"Christian Waniek, T. Wohlfahrt, J. Myrzik, Jan Meyer, P. Schegner","doi":"10.24084/repqj16.297","DOIUrl":"https://doi.org/10.24084/repqj16.297","url":null,"abstract":"","PeriodicalId":21007,"journal":{"name":"Renewable energy & power quality journal","volume":"52 3 1","pages":"316-319"},"PeriodicalIF":0.0,"publicationDate":"2018-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90078189","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
T. Masood, Nasir Jameels, S. Qureshi, M. Tajammal, Samer Karim Shah, G. Hashmi
The UPFC is a state-of-the-art control device that has the ability to enhance electrical power system network operation more precisely and effectively. This device encompasses of shunt and series parts to readjust capacitive and inductive compensation of the network based on their ratings to dynamically control the operating parameters of the transmission-network. These dynamic parameters comprise of phase angles, line impedance and line voltage. During the detailed investigation, a set of equations are introduced to compute UPFC operations/control behaviour on shared two bus system networks. In fact, the EMTP and Matlab models are introduced and customized to determine and validate UPFC effectiveness with precision. In this investigation, a pragmatic approach demonstrated and provided roadmap for the planning and control electrical engineer to evaluate UPFC operational behaviour and its significant impact on Electrical power transmission network operations. This device has the ability to address all types of time based contingencies in order for a seamless operation.
{"title":"Unified Power Flow Controller (UPFC) Modeling and Analysis Technique by using Matlab and EMTP","authors":"T. Masood, Nasir Jameels, S. Qureshi, M. Tajammal, Samer Karim Shah, G. Hashmi","doi":"10.24084/repqj16.250","DOIUrl":"https://doi.org/10.24084/repqj16.250","url":null,"abstract":"The UPFC is a state-of-the-art control device that has the ability to enhance electrical power system network operation more precisely and effectively. This device encompasses of shunt and series parts to readjust capacitive and inductive compensation of the network based on their ratings to dynamically control the operating parameters of the transmission-network. These dynamic parameters comprise of phase angles, line impedance and line voltage. During the detailed investigation, a set of equations are introduced to compute UPFC operations/control behaviour on shared two bus system networks. In fact, the EMTP and Matlab models are introduced and customized to determine and validate UPFC effectiveness with precision. In this investigation, a pragmatic approach demonstrated and provided roadmap for the planning and control electrical engineer to evaluate UPFC operational behaviour and its significant impact on Electrical power transmission network operations. This device has the ability to address all types of time based contingencies in order for a seamless operation.","PeriodicalId":21007,"journal":{"name":"Renewable energy & power quality journal","volume":"62 16","pages":"164-169"},"PeriodicalIF":0.0,"publicationDate":"2018-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91514671","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. Montoya, M. R. Rodríguez-Sánchez, J. López-Puente, D. Santana
Failure in the tubes of the solar receiver is a problem that should be studied. This failure is caused by the combined action of the high temperature, stresses and corrosion. Commonly, the calculation of the stresses in the receiver tubes is carried out in the crossed sections, taking into account the radial and the circumferential variation of the temperature. However, the temperature gradient along the tube length has been ignored. In this study a new model for the stress calculation in the receiver tubes has been developed. This model includes the temperature gradient in circumferential, radial, and longitudinal direction, taking into account the movement restrictions. The results show that the mechanical boundary conditions have a large effect in the stresses of the tube, being 3 times higher than the stress when no movement restrictions have been imposed. Moreover, the stress profile is highly dependent on the temperature gradient and hence on the incident solar flux on the receiver. Homogeneous solar fluxes are then more suitable than lower levels of solar fluxes with important gradients.
{"title":"Thermal and mechanical stresses in a solar central receiver","authors":"A. Montoya, M. R. Rodríguez-Sánchez, J. López-Puente, D. Santana","doi":"10.24084/REPQJ16.376","DOIUrl":"https://doi.org/10.24084/REPQJ16.376","url":null,"abstract":"Failure in the tubes of the solar receiver is a problem that should be studied. This failure is caused by the combined action of the high temperature, stresses and corrosion. Commonly, the calculation of the stresses in the receiver tubes is carried out in the crossed sections, taking into account the radial and the circumferential variation of the temperature. However, the temperature gradient along the tube length has been ignored. In this study a new model for the stress calculation in the receiver tubes has been developed. This model includes the temperature gradient in circumferential, radial, and longitudinal direction, taking into account the movement restrictions. The results show that the mechanical boundary conditions have a large effect in the stresses of the tube, being 3 times higher than the stress when no movement restrictions have been imposed. Moreover, the stress profile is highly dependent on the temperature gradient and hence on the incident solar flux on the receiver. Homogeneous solar fluxes are then more suitable than lower levels of solar fluxes with important gradients.","PeriodicalId":21007,"journal":{"name":"Renewable energy & power quality journal","volume":"106 1","pages":"528-532"},"PeriodicalIF":0.0,"publicationDate":"2018-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85549350","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Gheisa R. T. Esteves, M. Cunha, Wesley de C. Fagundes, R. Souza, A. D. Silva
{"title":"Solar Energy Potential and Time of Use Tariffs: a study case for Sao Luiz do Paraitinga","authors":"Gheisa R. T. Esteves, M. Cunha, Wesley de C. Fagundes, R. Souza, A. D. Silva","doi":"10.24084/repqj16.432","DOIUrl":"https://doi.org/10.24084/repqj16.432","url":null,"abstract":"","PeriodicalId":21007,"journal":{"name":"Renewable energy & power quality journal","volume":"32 1","pages":"680-685"},"PeriodicalIF":0.0,"publicationDate":"2018-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75068377","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
HVDC supergrid must grow in an organized way. The objective of HVDC substations will be to integrate generation groups and occasionally connect them to the AC network. That way, all substations will not be identical and their relevance will not be the same. In AC substations, network topological changes are made to limit the short circuit current contributions, perform load distributions and allow maintenance work when the application of restrictions is necessary, without compromising generation. These maintenance tasks should allow the exploitation of the network without making concessions on the stability of the system. DC networks do not require topological changes in the network to distribute loads, its utility would be reduced to facilitate maintenance tasks and minimize the possible effects of faults. However, it must be discussed which is the most suitable switchyard or whether more than one switchyard are required such as in AC networks. In the paper the usual topologies and switchyard configurations are analyzed and compared to determine if the architectures inherited from the AC grids can be used in the future HVDC supergrid. Several DC switchyard configurations are also discussed. Finally, the most suitable configurations are compared and applied to a study case.
{"title":"DC Switchyard Configurations for the Integration of Distributed Energy Resources","authors":"A. Hermosilla, D. M. Larruskain, P. Eguía","doi":"10.24084/repqj16.395","DOIUrl":"https://doi.org/10.24084/repqj16.395","url":null,"abstract":"HVDC supergrid must grow in an organized way. The objective of HVDC substations will be to integrate generation groups and occasionally connect them to the AC network. That way, all substations will not be identical and their relevance will not be the same. In AC substations, network topological changes are made to limit the short circuit current contributions, perform load distributions and allow maintenance work when the application of restrictions is necessary, without compromising generation. These maintenance tasks should allow the exploitation of the network without making concessions on the stability of the system. DC networks do not require topological changes in the network to distribute loads, its utility would be reduced to facilitate maintenance tasks and minimize the possible effects of faults. However, it must be discussed which is the most suitable switchyard or whether more than one switchyard are required such as in AC networks. In the paper the usual topologies and switchyard configurations are analyzed and compared to determine if the architectures inherited from the AC grids can be used in the future HVDC supergrid. Several DC switchyard configurations are also discussed. Finally, the most suitable configurations are compared and applied to a study case.","PeriodicalId":21007,"journal":{"name":"Renewable energy & power quality journal","volume":"124 1","pages":"578-583"},"PeriodicalIF":0.0,"publicationDate":"2018-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75588237","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：