A. Nuttapat Jittratorn, B. Chao-Ming Huang, C. Hong-Tzer Yang
A Markov chain (MC) model is a statistical method of predicting future outcomes using past experience. This study proposes a hybrid method that uses a long short-term memory (LSTM) and a MC method to produce very accurate short-term (10-min) forecasts for the power output from a wind turbine (WT). The proposed method has three stages. The first stage uses kmeans clustering to partition the wind power data into several clusters. The second stage uses LSTM models to initially predict the wind power output for each cluster. The final stage uses a MC method to construct the transition probability matrix for every 10- mimute time period. Using the transition probability matrices, the final predicted value for the WT power output is estimated using the prediction results for each cluster in the LSTM. This article also suggests a wind speed correction approach to enhance the forecasted wind speed result achieved by applying the weather research and forecasting model in order to generate more accurate wind power forecasting results. The proposed method is tested using a 3.6 MW WT power generation system that is located in Changhua, Taiwan. The effectiveness of the proposed model is compared with support vector regression (SVR), random forest (RF), LSTM and bidirectional gated recurrent unit (Bi-GRU) methods.
{"title":"Very Short-Term Wind Power Forecasting Using a Hybrid LSTMMarkov Model Based on Corrected Wind Speed","authors":"A. Nuttapat Jittratorn, B. Chao-Ming Huang, C. Hong-Tzer Yang","doi":"10.24084/repqj21.347","DOIUrl":"https://doi.org/10.24084/repqj21.347","url":null,"abstract":"A Markov chain (MC) model is a statistical method of predicting future outcomes using past experience. This study proposes a hybrid method that uses a long short-term memory (LSTM) and a MC method to produce very accurate short-term (10-min) forecasts for the power output from a wind turbine (WT). The proposed method has three stages. The first stage uses kmeans clustering to partition the wind power data into several clusters. The second stage uses LSTM models to initially predict the wind power output for each cluster. The final stage uses a MC method to construct the transition probability matrix for every 10- mimute time period. Using the transition probability matrices, the final predicted value for the WT power output is estimated using the prediction results for each cluster in the LSTM. This article also suggests a wind speed correction approach to enhance the forecasted wind speed result achieved by applying the weather research and forecasting model in order to generate more accurate wind power forecasting results. The proposed method is tested using a 3.6 MW WT power generation system that is located in Changhua, Taiwan. The effectiveness of the proposed model is compared with support vector regression (SVR), random forest (RF), LSTM and bidirectional gated recurrent unit (Bi-GRU) methods.","PeriodicalId":21076,"journal":{"name":"Renewable Energy and Power Quality Journal","volume":"268 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77169215","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}
Harmonic distortions are known to affect the normal operation and life of power equipment. Shunt capacitor is one piece of equipment that is very sensitive to harmonics. Although limits have been established to limit the harmonic distortions experienced by a capacitor, methods to quantify the harmonic impact with easy-to-understand indices are still at large. This paper aims to address the above gap by proposing an equivalent voltage index. This index is to represent the impact of harmonic voltages and their features (such as peak value) into an equivalent increase in the fundamental frequency voltage otherwise experienced by the capacitor. The main advantage of such an equivalence is that PQ and non-PQ engineers can easily relate the impact to the general capacitor loading concept. The index is especially helpful to understand the impact of harmonics on capacitor and thus to justify harmonic mitigation projects.
{"title":"An Equivalent Voltage Index to Quantify the Impact of Harmonics on Shunt Capacitors","authors":"Tian Yu, Jing Yong, Wilsun Xu","doi":"10.24084/repqj21.223","DOIUrl":"https://doi.org/10.24084/repqj21.223","url":null,"abstract":"Harmonic distortions are known to affect the normal operation and life of power equipment. Shunt capacitor is one piece of equipment that is very sensitive to harmonics. Although limits have been established to limit the harmonic distortions experienced by a capacitor, methods to quantify the harmonic impact with easy-to-understand indices are still at large. This paper aims to address the above gap by proposing an equivalent voltage index. This index is to represent the impact of harmonic voltages and their features (such as peak value) into an equivalent increase in the fundamental frequency voltage otherwise experienced by the capacitor. The main advantage of such an equivalence is that PQ and non-PQ engineers can easily relate the impact to the general capacitor loading concept. The index is especially helpful to understand the impact of harmonics on capacitor and thus to justify harmonic mitigation projects.","PeriodicalId":21076,"journal":{"name":"Renewable Energy and Power Quality Journal","volume":"43 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78560708","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}
L. Vargas, R. Rengel, J. Caparrós, D. Tejada-Guzmán, E. López
Renewable energy sources have demonstrated in recent years their ability to reduce the dependence on fossil fuels, contribute to the security of energy supply and play an important role in reducing greenhouse gas emissions. To benefit from the local use of renewable sources and energy efficiency in distributed systems, the concept of local energy communities is established. In local energy communities, new innovative technologies are combined, highlighting the role of energy storage, to provide greater autonomy to communities that adopt this model. Among energy storage, the use of batteries stands out, while lithium batteries are currently the most widely used for domestic and residential applications, as well as in local energy communities. This work describes the experimental evaluation of an innovative energy storage system for energy communities based on hybrid supercapacitors (HSC), focused on local energy communities, and its comparison with other well established storage technologies, such as lithium-ion batteries.
{"title":"Technical evaluation of hybrid super capacitor technologies for local energy communities","authors":"L. Vargas, R. Rengel, J. Caparrós, D. Tejada-Guzmán, E. López","doi":"10.24084/repqj21.393","DOIUrl":"https://doi.org/10.24084/repqj21.393","url":null,"abstract":"Renewable energy sources have demonstrated in recent years their ability to reduce the dependence on fossil fuels, contribute to the security of energy supply and play an important role in reducing greenhouse gas emissions. To benefit from the local use of renewable sources and energy efficiency in distributed systems, the concept of local energy communities is established. In local energy communities, new innovative technologies are combined, highlighting the role of energy storage, to provide greater autonomy to communities that adopt this model. Among energy storage, the use of batteries stands out, while lithium batteries are currently the most widely used for domestic and residential applications, as well as in local energy communities. This work describes the experimental evaluation of an innovative energy storage system for energy communities based on hybrid supercapacitors (HSC), focused on local energy communities, and its comparison with other well established storage technologies, such as lithium-ion batteries.","PeriodicalId":21076,"journal":{"name":"Renewable Energy and Power Quality Journal","volume":"61 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73169414","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}
In this paper, a hybrid vibration energy harvesting system based on piezoelectricity and electro-magnetic devices is modelled and simulated in a software environment. The integrated system includes harvesting devices, power electronics and the load. The converter is controlled to maintain proper voltage and current at the load side. Simulation results are provided to show the operation of each device in the integrated harvesting system.
{"title":"Design, Modelling and Simulation of Hybrid Vibration Energy Harvesting System using Integration of Piezoelectricity and ElectroMagnetism","authors":"R. Embuldeniya, A. Merabet","doi":"10.24084/repqj21.425","DOIUrl":"https://doi.org/10.24084/repqj21.425","url":null,"abstract":"In this paper, a hybrid vibration energy harvesting system based on piezoelectricity and electro-magnetic devices is modelled and simulated in a software environment. The integrated system includes harvesting devices, power electronics and the load. The converter is controlled to maintain proper voltage and current at the load side. Simulation results are provided to show the operation of each device in the integrated harvesting system.","PeriodicalId":21076,"journal":{"name":"Renewable Energy and Power Quality Journal","volume":"354 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76479531","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}
New technical solutions are beginning to emerge, of which the Floating Solar Photovoltaic (FSPV) systems, is a promising new technology growing rapidly in the recent years. Portugal is a good example in Europe with several facilities of this type. For a correct management of these systems, and to have significant data, it is necessary to have a reliable communication system, based on a Global System for Mobile Communications, adequate protocols to communicate and save the data for later analyses. This study aims to develop a climate data acquisition system to be placed next to an FSPV system installed on a farm next to the Douro River. This system is installed in a box over the water surface. To allow comparison of temperature variations over the water surface with the temperature (offshore) another box with similar sensors is placed on land (onshore). With the data collected by these two systems is possible to compare the temperature data in two boxes, installed in these different locations, to analyse the influence of the water mirror on the photovoltaic cell efficiency.
{"title":"IoT-Internet of Things in Floating Solar Photovoltaic Systems","authors":"P. Vargas, A. Valente","doi":"10.24084/repqj21.459","DOIUrl":"https://doi.org/10.24084/repqj21.459","url":null,"abstract":"New technical solutions are beginning to emerge, of which the Floating Solar Photovoltaic (FSPV) systems, is a promising new technology growing rapidly in the recent years. Portugal is a good example in Europe with several facilities of this type. For a correct management of these systems, and to have significant data, it is necessary to have a reliable communication system, based on a Global System for Mobile Communications, adequate protocols to communicate and save the data for later analyses. This study aims to develop a climate data acquisition system to be placed next to an FSPV system installed on a farm next to the Douro River. This system is installed in a box over the water surface. To allow comparison of temperature variations over the water surface with the temperature (offshore) another box with similar sensors is placed on land (onshore). With the data collected by these two systems is possible to compare the temperature data in two boxes, installed in these different locations, to analyse the influence of the water mirror on the photovoltaic cell efficiency.","PeriodicalId":21076,"journal":{"name":"Renewable Energy and Power Quality Journal","volume":"338 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74930370","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}
The statistical uncertainty quantification of the injected uncertainties into a power system has been done to study the response of the power system to such injected randomness. The dominant electromechanical modes have been analysed and the frequency spectrum of the trajectories obtained for various state variables has been used to measure the impact of injected randomness on the system. The idea of Statistical Distance between the point of input perturbations and output measurement data has been explored. The simulation results indicate that there is a direct relationship between the input uncertainty and output measurement variable and is greatly affected by the magnitude and location of random injection. The above framework has been validated using Kundur's two area system and IEEE 14 Bus system.
{"title":"Impact of Uncertainty Quantification on Small Signal Stability of Power System","authors":"Suravi Thakur, N. Senroy","doi":"10.24084/repqj21.210","DOIUrl":"https://doi.org/10.24084/repqj21.210","url":null,"abstract":"The statistical uncertainty quantification of the injected uncertainties into a power system has been done to study the response of the power system to such injected randomness. The dominant electromechanical modes have been analysed and the frequency spectrum of the trajectories obtained for various state variables has been used to measure the impact of injected randomness on the system. The idea of Statistical Distance between the point of input perturbations and output measurement data has been explored. The simulation results indicate that there is a direct relationship between the input uncertainty and output measurement variable and is greatly affected by the magnitude and location of random injection. The above framework has been validated using Kundur's two area system and IEEE 14 Bus system.","PeriodicalId":21076,"journal":{"name":"Renewable Energy and Power Quality Journal","volume":"61 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73792832","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}
Djamila Rekioua, F. Zaouche, Z. Mokrani, T. Rekioua
A study of a stand-alone photovoltaic./batteries/fuel cell power system has been presented in this paper to produce energy continuously. A management control circuit (PMC) has been designed to obtain the different control signals that allow supervising power flow of the hybrid system. The application has been made to a stand-alone system for four days at Bejaia region. Fuzzy logic Control (FLC) is used to optimize power The structures PV/Battery/Fuel cells system have been investigated. A modelisation of each component has been made. A supervisor control circuit has been designed to obtain the various control signals needed to control the overall system. A simulation study has been done in Matlab. The different results are presented to show the effectiveness of the proposed strategy
{"title":"Power Management Control of photovoltaic/Batteries/Fuel cells System","authors":"Djamila Rekioua, F. Zaouche, Z. Mokrani, T. Rekioua","doi":"10.24084/repqj21.344","DOIUrl":"https://doi.org/10.24084/repqj21.344","url":null,"abstract":"A study of a stand-alone photovoltaic./batteries/fuel cell power system has been presented in this paper to produce energy continuously. A management control circuit (PMC) has been designed to obtain the different control signals that allow supervising power flow of the hybrid system. The application has been made to a stand-alone system for four days at Bejaia region. Fuzzy logic Control (FLC) is used to optimize power The structures PV/Battery/Fuel cells system have been investigated. A modelisation of each component has been made. A supervisor control circuit has been designed to obtain the various control signals needed to control the overall system. A simulation study has been done in Matlab. The different results are presented to show the effectiveness of the proposed strategy","PeriodicalId":21076,"journal":{"name":"Renewable Energy and Power Quality Journal","volume":"125 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78091413","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}
Achieving acceptable air quality levels in indoor spaces by regulating the concentrations of H2O and CO2 is important for occupant health. Conventional techniques rely on supplying dehumidified outdoor air to dilute these species to within their healthy ranges. Typically, the outdoor air dehumidification is conducted using vapor compression cooling either as standalone systems or integrated with desiccant dehumidifiers. These methods are known to be energy intensive, especially in hot and humid climates. Ventilation systems using indoor air with adsorption-based CO2 capture are thus proposed. These systems use adsorbent packed beds to dehumidify and decarbonize the indoor air before it is sensibly cooled and supplied to the space. For energy efficient operation of these systems, heat recovery units are necessary. In this work, heat and mass balance models were developed and used to determine the optimal placement location of the heat recovery units. It was found that a heat exchanger preceding the decarbonization bed increased the MOFs capacity, resulting in 33 % lower mass requirements. This was accompanied by a reduction in the thermal and electrical energy consumption by 43.5 % and 25 %, respectively, with respect to the configuration where the heat exchanger was placed after both air treatment systems.
{"title":"Optimal Placement of Heat Exchangers in a Carbon Capture-Based Ventilation System","authors":"J. P. Harrouz, K. Ghali, N. Ghaddar","doi":"10.24084/repqj21.325","DOIUrl":"https://doi.org/10.24084/repqj21.325","url":null,"abstract":"Achieving acceptable air quality levels in indoor spaces by regulating the concentrations of H2O and CO2 is important for occupant health. Conventional techniques rely on supplying dehumidified outdoor air to dilute these species to within their healthy ranges. Typically, the outdoor air dehumidification is conducted using vapor compression cooling either as standalone systems or integrated with desiccant dehumidifiers. These methods are known to be energy intensive, especially in hot and humid climates. Ventilation systems using indoor air with adsorption-based CO2 capture are thus proposed. These systems use adsorbent packed beds to dehumidify and decarbonize the indoor air before it is sensibly cooled and supplied to the space. For energy efficient operation of these systems, heat recovery units are necessary. In this work, heat and mass balance models were developed and used to determine the optimal placement location of the heat recovery units. It was found that a heat exchanger preceding the decarbonization bed increased the MOFs capacity, resulting in 33 % lower mass requirements. This was accompanied by a reduction in the thermal and electrical energy consumption by 43.5 % and 25 %, respectively, with respect to the configuration where the heat exchanger was placed after both air treatment systems.","PeriodicalId":21076,"journal":{"name":"Renewable Energy and Power Quality Journal","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81186672","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}
While large wind farms are well monitored, with a wealth of data provided through a SCADA system, the only information about the behaviour of small wind turbines is often only through the metered electricity production. Given the variable electricity output, it is difficult to ascertain whether a particular electricity production in a metering period is the result of the turbine operating normally, or if a fault is resulting in a production less than possible. This paper presents a method to correlate metered electricity output from a set of 5 kW wind turbines with weather information from a weather station some distance from the turbine. That correlation will then be classified into ‘expected’ and ‘unusual’ performance using Principal Component Analysis.
{"title":"A method to assess the performance of small wind turbines","authors":"W. Früh","doi":"10.24084/repqj21.436","DOIUrl":"https://doi.org/10.24084/repqj21.436","url":null,"abstract":"While large wind farms are well monitored, with a wealth of data provided through a SCADA system, the only information about the behaviour of small wind turbines is often only through the metered electricity production. Given the variable electricity output, it is difficult to ascertain whether a particular electricity production in a metering period is the result of the turbine operating normally, or if a fault is resulting in a production less than possible. This paper presents a method to correlate metered electricity output from a set of 5 kW wind turbines with weather information from a weather station some distance from the turbine. That correlation will then be classified into ‘expected’ and ‘unusual’ performance using Principal Component Analysis.","PeriodicalId":21076,"journal":{"name":"Renewable Energy and Power Quality Journal","volume":"63 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82357068","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}
The use of a mathematical tool such as the logistic curve to analyze the performance of wind energy and public investment in R&D by different countries throughout the history of the technology has allowed this study to draw conclusions on how the different countries studied have dealt with the problem of technological obsolescence.
{"title":"Technology S-curves in wind energy: a comparative analysis","authors":"Fernando Estévez Garcia, Jeanne-Marie Dalbavie","doi":"10.24084/repqj21.250","DOIUrl":"https://doi.org/10.24084/repqj21.250","url":null,"abstract":"The use of a mathematical tool such as the logistic curve to analyze the performance of wind energy and public investment in R&D by different countries throughout the history of the technology has allowed this study to draw conclusions on how the different countries studied have dealt with the problem of technological obsolescence.","PeriodicalId":21076,"journal":{"name":"Renewable Energy and Power Quality Journal","volume":"44 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85224814","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}
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