Articles de revista
http://hdl.handle.net/2117/3863
2024-03-29T13:04:05Z
2024-03-29T13:04:05Z
Detection of abnormal operation of PV inverters based on regressive prediction models with recursive least squares training
Moreno Kübel, Pablo Alexander
Laguna Benet, Gerard
Cipriano Lindez, Jordi
Luna Alloza, Álvaro
http://hdl.handle.net/2117/400894
2024-02-11T07:07:37Z
2024-02-02T13:15:30Z
Detection of abnormal operation of PV inverters based on regressive prediction models with recursive least squares training
Moreno Kübel, Pablo Alexander; Laguna Benet, Gerard; Cipriano Lindez, Jordi; Luna Alloza, Álvaro
The large scale integration of photovoltaic (PV) power plants has launched the massive deployment of PV inverters. In fact, just a single multi-MW PV plant may have thousands of them, which can be also found isolated in low scale distributed generation applications. The number of grid-connected assets can be no longer managed and maintained effectively without using AI tools, able to analyze their operation, detect faults and support decision-making maintenance tools. In this paper, a Linear Regression method able to detect abnormal operation in PV systems, based on a Recursive Least Squares (RLS) training algorithm, which requires a low amount of data, mainly energy generation measurements and meteorological data, is proposed. In addition, two different applications of this methodology will be presented, one based on issuing a simplified model for real-time analysis, and another one consisting of a complex model for long-term diagnosis. The first one is focused on detecting faults and abnormal operation profiles in real-time, while the second one permits assessing the historical efficiency decay of PV plants in longer periods. Both will be used for detecting abnormal operation of PV inverters and panels. The performance and behavior of these algorithms will be tested using the data of 22 PV plants, placed at different climatic areas and with different peak powers. The results will show the good performance of the proposed fault detection method in both applications.
2024-02-02T13:15:30Z
Moreno Kübel, Pablo Alexander
Laguna Benet, Gerard
Cipriano Lindez, Jordi
Luna Alloza, Álvaro
The large scale integration of photovoltaic (PV) power plants has launched the massive deployment of PV inverters. In fact, just a single multi-MW PV plant may have thousands of them, which can be also found isolated in low scale distributed generation applications. The number of grid-connected assets can be no longer managed and maintained effectively without using AI tools, able to analyze their operation, detect faults and support decision-making maintenance tools. In this paper, a Linear Regression method able to detect abnormal operation in PV systems, based on a Recursive Least Squares (RLS) training algorithm, which requires a low amount of data, mainly energy generation measurements and meteorological data, is proposed. In addition, two different applications of this methodology will be presented, one based on issuing a simplified model for real-time analysis, and another one consisting of a complex model for long-term diagnosis. The first one is focused on detecting faults and abnormal operation profiles in real-time, while the second one permits assessing the historical efficiency decay of PV plants in longer periods. Both will be used for detecting abnormal operation of PV inverters and panels. The performance and behavior of these algorithms will be tested using the data of 22 PV plants, placed at different climatic areas and with different peak powers. The results will show the good performance of the proposed fault detection method in both applications.
Experimental energy performance assessment of a bifacial photovoltaic system and effect of cool roof coating
Valencia Caballero, Daniel
Bouchakour, Salim
Luna Alloza, Álvaro
Garcia Marco, Borja
Huidobro, Ana
Flores Abascal, Ivan
Sanz Martínez, Asier
Román, Eduardo
http://hdl.handle.net/2117/398876
2024-01-17T13:30:25Z
2024-01-09T11:08:12Z
Experimental energy performance assessment of a bifacial photovoltaic system and effect of cool roof coating
Valencia Caballero, Daniel; Bouchakour, Salim; Luna Alloza, Álvaro; Garcia Marco, Borja; Huidobro, Ana; Flores Abascal, Ivan; Sanz Martínez, Asier; Román, Eduardo
In the quest for high albedo materials that boost the energy production of bifacial photovoltaic systems, a range of material already exists for reducing building roof surface temperatures, called cool roof materials. However, there is a noticeable absence of scientific literature addressing the combination of cool roofs and bifacial photovoltaic systems. This study investigates the photovoltaic performance of a bifacial photovoltaic system with cool roof coating on the underside and its impact on floor temperature. For this purpose, four ~1kWp prototypes were installed on the terrace of the GAIA building of the UPC near Barcelona, Spain: (1) bifacial panels above a cool roof, (2) bifacial panels above normal floor, (3) bifacial panels above a normal floor with n-type solar cells encapsulated in TPO, and (4) monofacial panels. The results reveal 8.6 % higher PV yield for bifacial with cool roof compared to monofacial, and 4–4.5 % higher for bifacial (normal floor) compared to monofacial. Additionally, the cool roof coating contributes to reducing the floor temperatures, particularly in the unshaded (exposed) areas during summer (- 3.8 ¿C). The presence of photovoltaic panels has also demonstrated a positive impact on floor temperatures during both winter and summer. Thus, the cool roof coating offers two benefits: increased photovoltaic yield and reduced building cooling requirements, both of which are associated with economic advantages. The cool roof coating can be integrated into existing or new bifacial roof systems.
2024-01-09T11:08:12Z
Valencia Caballero, Daniel
Bouchakour, Salim
Luna Alloza, Álvaro
Garcia Marco, Borja
Huidobro, Ana
Flores Abascal, Ivan
Sanz Martínez, Asier
Román, Eduardo
In the quest for high albedo materials that boost the energy production of bifacial photovoltaic systems, a range of material already exists for reducing building roof surface temperatures, called cool roof materials. However, there is a noticeable absence of scientific literature addressing the combination of cool roofs and bifacial photovoltaic systems. This study investigates the photovoltaic performance of a bifacial photovoltaic system with cool roof coating on the underside and its impact on floor temperature. For this purpose, four ~1kWp prototypes were installed on the terrace of the GAIA building of the UPC near Barcelona, Spain: (1) bifacial panels above a cool roof, (2) bifacial panels above normal floor, (3) bifacial panels above a normal floor with n-type solar cells encapsulated in TPO, and (4) monofacial panels. The results reveal 8.6 % higher PV yield for bifacial with cool roof compared to monofacial, and 4–4.5 % higher for bifacial (normal floor) compared to monofacial. Additionally, the cool roof coating contributes to reducing the floor temperatures, particularly in the unshaded (exposed) areas during summer (- 3.8 ¿C). The presence of photovoltaic panels has also demonstrated a positive impact on floor temperatures during both winter and summer. Thus, the cool roof coating offers two benefits: increased photovoltaic yield and reduced building cooling requirements, both of which are associated with economic advantages. The cool roof coating can be integrated into existing or new bifacial roof systems.
Battery and hydrogen energy storage control in a smart energy network with flexible energy demand using deep reinforcement learning
Samende, Cephas
Fan, Zhong
Cao, Jun
Espinoza, Renzo Fabián
Baltas, Gregory Nicholas
Rodríguez Cortés, Pedro
http://hdl.handle.net/2117/395808
2023-11-05T19:13:55Z
2023-11-03T15:27:10Z
Battery and hydrogen energy storage control in a smart energy network with flexible energy demand using deep reinforcement learning
Samende, Cephas; Fan, Zhong; Cao, Jun; Espinoza, Renzo Fabián; Baltas, Gregory Nicholas; Rodríguez Cortés, Pedro
Smart energy networks provide an effective means to accommodate high penetrations of variable renewable energy sources like solar and wind, which are key for the deep decarbonisation of energy production. However, given the variability of the renewables as well as the energy demand, it is imperative to develop effective control and energy storage schemes to manage the variable energy generation and achieve desired system economics and environmental goals. In this paper, we introduce a hybrid energy storage system composed of battery and hydrogen energy storage to handle the uncertainties related to electricity prices, renewable energy production, and consumption. We aim to improve renewable energy utilisation and minimise energy costs and carbon emissions while ensuring energy reliability and stability within the network. To achieve this, we propose a multi-agent deep deterministic policy gradient approach, which is a deep reinforcement learning-based control strategy to optimise the scheduling of the hybrid energy storage system and energy demand in real time. The proposed approach is model-free and does not require explicit knowledge and rigorous mathematical models of the smart energy network environment. Simulation results based on real-world data show that (i) integration and optimised operation of the hybrid energy storage system and energy demand reduce carbon emissions by 78.69%, improve cost savings by 23.5%, and improve renewable energy utilisation by over 13.2% compared to other baseline models; and (ii) the proposed algorithm outperforms the state-of-the-art self-learning algorithms like the deep-Q network.
2023-11-03T15:27:10Z
Samende, Cephas
Fan, Zhong
Cao, Jun
Espinoza, Renzo Fabián
Baltas, Gregory Nicholas
Rodríguez Cortés, Pedro
Smart energy networks provide an effective means to accommodate high penetrations of variable renewable energy sources like solar and wind, which are key for the deep decarbonisation of energy production. However, given the variability of the renewables as well as the energy demand, it is imperative to develop effective control and energy storage schemes to manage the variable energy generation and achieve desired system economics and environmental goals. In this paper, we introduce a hybrid energy storage system composed of battery and hydrogen energy storage to handle the uncertainties related to electricity prices, renewable energy production, and consumption. We aim to improve renewable energy utilisation and minimise energy costs and carbon emissions while ensuring energy reliability and stability within the network. To achieve this, we propose a multi-agent deep deterministic policy gradient approach, which is a deep reinforcement learning-based control strategy to optimise the scheduling of the hybrid energy storage system and energy demand in real time. The proposed approach is model-free and does not require explicit knowledge and rigorous mathematical models of the smart energy network environment. Simulation results based on real-world data show that (i) integration and optimised operation of the hybrid energy storage system and energy demand reduce carbon emissions by 78.69%, improve cost savings by 23.5%, and improve renewable energy utilisation by over 13.2% compared to other baseline models; and (ii) the proposed algorithm outperforms the state-of-the-art self-learning algorithms like the deep-Q network.
Control of a three-phase active transformer integrating energy storage
Vidal León Romay, José David
Tarraso Martínez, Andrés
Candela García, José Ignacio
Rocabert Delgado, Joan
Luna Alloza, Álvaro
Rodríguez Cortés, Pedro
http://hdl.handle.net/2117/394735
2023-10-22T01:34:27Z
2023-10-06T16:58:34Z
Control of a three-phase active transformer integrating energy storage
Vidal León Romay, José David; Tarraso Martínez, Andrés; Candela García, José Ignacio; Rocabert Delgado, Joan; Luna Alloza, Álvaro; Rodríguez Cortés, Pedro
The high penetration of distributed energy sources is changing the paradigm of electrical networks control and management. Nowadays, power conversion systems associated to green energy plants are not only required to deliver power according to an MPPT algorithm, but should also participate in the regulation and operation of the power system, in the case of large scale systems, or provide advanced features to end users in the case of prosumers. This work proposes the use of an active transformer, incorporating series voltage regulation and current shunt regulation, through two converters in back-to-back configuration, which is able to provide all power quality services as well as resilience to end-users. This topology is advantageous in case of prosumers connected to weak and faulty grids. Moreover, the proposed active transformer also includes a battery so that island operation is offered as a service. Throughout the paper, the stability analyses and the implementation of an active transformer are presented, with special emphasis on the control of the series converter. The proposed topology is validated through real time simulations and an experimental prototype which includes a 300 kWh energy storage installation.
©2023 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.
2023-10-06T16:58:34Z
Vidal León Romay, José David
Tarraso Martínez, Andrés
Candela García, José Ignacio
Rocabert Delgado, Joan
Luna Alloza, Álvaro
Rodríguez Cortés, Pedro
The high penetration of distributed energy sources is changing the paradigm of electrical networks control and management. Nowadays, power conversion systems associated to green energy plants are not only required to deliver power according to an MPPT algorithm, but should also participate in the regulation and operation of the power system, in the case of large scale systems, or provide advanced features to end users in the case of prosumers. This work proposes the use of an active transformer, incorporating series voltage regulation and current shunt regulation, through two converters in back-to-back configuration, which is able to provide all power quality services as well as resilience to end-users. This topology is advantageous in case of prosumers connected to weak and faulty grids. Moreover, the proposed active transformer also includes a battery so that island operation is offered as a service. Throughout the paper, the stability analyses and the implementation of an active transformer are presented, with special emphasis on the control of the series converter. The proposed topology is validated through real time simulations and an experimental prototype which includes a 300 kWh energy storage installation.
Grid forming control for power converters based on an Inertial Phase Locked Loop (IPLL)
Tarraso Martínez, Andrés
Candela García, José Ignacio
Rocabert Delgado, Joan
Luna Alloza, Álvaro
Miletic, Zoran
http://hdl.handle.net/2117/393308
2023-09-11T02:17:12Z
2023-09-08T13:41:17Z
Grid forming control for power converters based on an Inertial Phase Locked Loop (IPLL)
Tarraso Martínez, Andrés; Candela García, José Ignacio; Rocabert Delgado, Joan; Luna Alloza, Álvaro; Miletic, Zoran
Inertia emulation is claimed to play a decisive role in the regulation and management of frequency in modern electrical systems. The support offered by renewable energy power plants and distributed generators is key to diminish the rate of change of frequency (RoCoF), as many synchronous generators are being replaced all around the globe. It is a reality that the implementation of the swing equation in the power converter control has been the core of several proposals on grid-forming controllers to emulate inertia. This kind of controller has been heavily studied and integrated in some demonstrators around the world during the last years, providing dynamic inertia support functionalities. However, the need to modify the synchronization strategy in already deployed power units has been one of the key opposition factors on industry, leading to a severe shortcoming on the integration. In contrast to the traditional swing equation implementation this paper presents a lightweight inertial phase-locked loop (IPLL) able to take the most of inertial features introducing minor changes on classical power converter control and synchronization structures. As shown in this work, the straightforward implementation significantly reduces the technological and computational effort compared to other synchronous emulation proposals. Moreover, it integrates not only dynamic inertial response to the converter, but also all grid-forming capacities to the power conversion unit. This modification on the synchronization structure enables the converter to work in grid-following mode in grid-tied applications, and grid-forming in islanded ones. The integration of the proposed IPLL, the stability analysis and a sample of its performance in HIL and experimental environments will be presented in this paper.
2023-09-08T13:41:17Z
Tarraso Martínez, Andrés
Candela García, José Ignacio
Rocabert Delgado, Joan
Luna Alloza, Álvaro
Miletic, Zoran
Inertia emulation is claimed to play a decisive role in the regulation and management of frequency in modern electrical systems. The support offered by renewable energy power plants and distributed generators is key to diminish the rate of change of frequency (RoCoF), as many synchronous generators are being replaced all around the globe. It is a reality that the implementation of the swing equation in the power converter control has been the core of several proposals on grid-forming controllers to emulate inertia. This kind of controller has been heavily studied and integrated in some demonstrators around the world during the last years, providing dynamic inertia support functionalities. However, the need to modify the synchronization strategy in already deployed power units has been one of the key opposition factors on industry, leading to a severe shortcoming on the integration. In contrast to the traditional swing equation implementation this paper presents a lightweight inertial phase-locked loop (IPLL) able to take the most of inertial features introducing minor changes on classical power converter control and synchronization structures. As shown in this work, the straightforward implementation significantly reduces the technological and computational effort compared to other synchronous emulation proposals. Moreover, it integrates not only dynamic inertial response to the converter, but also all grid-forming capacities to the power conversion unit. This modification on the synchronization structure enables the converter to work in grid-following mode in grid-tied applications, and grid-forming in islanded ones. The integration of the proposed IPLL, the stability analysis and a sample of its performance in HIL and experimental environments will be presented in this paper.
Grid-forming controller based on virtual admittance for power converters working in weak grids
Vidal León Romay, José David
Tarraso Martínez, Andrés
Candela García, José Ignacio
Rocabert Delgado, Joan
Rodríguez Cortés, Pedro
http://hdl.handle.net/2117/390616
2023-10-22T04:15:53Z
2023-07-11T10:43:59Z
Grid-forming controller based on virtual admittance for power converters working in weak grids
Vidal León Romay, José David; Tarraso Martínez, Andrés; Candela García, José Ignacio; Rocabert Delgado, Joan; Rodríguez Cortés, Pedro
The high penetration of distributed energy resources, based on power electronics, is giving rise to stability issues in the electrical network, as initially those plants were not required to provide either voltage or frequency support. Due to this, transmission system operators (TSOs) and distribution system operators (DSOs) have set new requirements for them to provide grid support functionalities. This article presents a grid forming control strategy for power converters which is based on a virtual admittance loop. By means of this strategy it is possible to use a conventional current control based inverter, just adding this outer loop. By doing so, the converter is not only able to perform current control, but also frequency and voltage support functionalities. In this article, the proposed control is described and analyzed, checking as well its stability boundaries. After this analysis, the results obtained in a hardware-in-the-loop platform, where faulty scenarios, islanding or black start conditions, will be shown. Finally, the results obtained in an experimental true scale workbench will show its effectiveness for providing such services.
©2023 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.
2023-07-11T10:43:59Z
Vidal León Romay, José David
Tarraso Martínez, Andrés
Candela García, José Ignacio
Rocabert Delgado, Joan
Rodríguez Cortés, Pedro
The high penetration of distributed energy resources, based on power electronics, is giving rise to stability issues in the electrical network, as initially those plants were not required to provide either voltage or frequency support. Due to this, transmission system operators (TSOs) and distribution system operators (DSOs) have set new requirements for them to provide grid support functionalities. This article presents a grid forming control strategy for power converters which is based on a virtual admittance loop. By means of this strategy it is possible to use a conventional current control based inverter, just adding this outer loop. By doing so, the converter is not only able to perform current control, but also frequency and voltage support functionalities. In this article, the proposed control is described and analyzed, checking as well its stability boundaries. After this analysis, the results obtained in a hardware-in-the-loop platform, where faulty scenarios, islanding or black start conditions, will be shown. Finally, the results obtained in an experimental true scale workbench will show its effectiveness for providing such services.
Control of energy storage system integrating electrochemical batteries and supercapacitors for grid-connected applications
Rocabert Delgado, Joan
Capo Misut, Ruben
Muñoz Aguilar, Raúl Santiago
Candela García, José Ignacio
Rodríguez Cortés, Pedro
http://hdl.handle.net/2117/385834
2023-04-02T19:29:51Z
2023-03-31T13:18:21Z
Control of energy storage system integrating electrochemical batteries and supercapacitors for grid-connected applications
Rocabert Delgado, Joan; Capo Misut, Ruben; Muñoz Aguilar, Raúl Santiago; Candela García, José Ignacio; Rodríguez Cortés, Pedro
The implementation of ancillary services in renewable energy based generation systems requires controlling bidirectional power flow. For such applications, integrated energy storage systems (ESSs) in such generation platforms have emerged as a promising solution. However, a large variety of ESS solutions are available in the market, and even hybrid systems are proposed to optimize the overall performance. In this regard, the integration of supercapacitors (SCs) and electrochemical batteries is an attractive and feasible solution, as it takes the most of the combination of the large storage capacity of batteries with the high dynamic performance of SCs. This combination enables the implementation of energy and power services, such as inertia emulation, black start, or power oscillation damping among others. This solution avoids oversizing ESS and enlarges the battery lifetime, since the SCs absorve the high dynamic response meanwhile the battery feeds an attenuated power profile. This paper presents a strategy to manage mixed energy storage technologies, composed by a direct connection of a battery and an SC bank interfaced through a dc-dc converter. A power control loop distributes the power flow through each element in order to achieve an optimized performance, meanwhile, it permits to provide grid-frequency support and minimizes the number of cycles applied to the battery. The analysis made and the initial sections are endorsed by simulation and experimental results collected in a 50-kW test-bench.
2023-03-31T13:18:21Z
Rocabert Delgado, Joan
Capo Misut, Ruben
Muñoz Aguilar, Raúl Santiago
Candela García, José Ignacio
Rodríguez Cortés, Pedro
The implementation of ancillary services in renewable energy based generation systems requires controlling bidirectional power flow. For such applications, integrated energy storage systems (ESSs) in such generation platforms have emerged as a promising solution. However, a large variety of ESS solutions are available in the market, and even hybrid systems are proposed to optimize the overall performance. In this regard, the integration of supercapacitors (SCs) and electrochemical batteries is an attractive and feasible solution, as it takes the most of the combination of the large storage capacity of batteries with the high dynamic performance of SCs. This combination enables the implementation of energy and power services, such as inertia emulation, black start, or power oscillation damping among others. This solution avoids oversizing ESS and enlarges the battery lifetime, since the SCs absorve the high dynamic response meanwhile the battery feeds an attenuated power profile. This paper presents a strategy to manage mixed energy storage technologies, composed by a direct connection of a battery and an SC bank interfaced through a dc-dc converter. A power control loop distributes the power flow through each element in order to achieve an optimized performance, meanwhile, it permits to provide grid-frequency support and minimizes the number of cycles applied to the battery. The analysis made and the initial sections are endorsed by simulation and experimental results collected in a 50-kW test-bench.
Análisis comparativo de propiedades termo estructurales y eléctricas entre polietileno de alta densidad (HD-PE), y el HD-DE reforzado con neumáticos al final de su vida útil. Estudio de aplicación como dieléctrico
Marín Genescà, Marc
Mujal-Rosas, Ramon Maria
Garcia Amoros, Jordi
Massagués Vidal, Lluís
Pou Ibar, Josep Oriol
Colom Fajula, Xavier
http://hdl.handle.net/2117/368398
2022-06-14T09:40:41Z
2022-06-14T09:31:53Z
Análisis comparativo de propiedades termo estructurales y eléctricas entre polietileno de alta densidad (HD-PE), y el HD-DE reforzado con neumáticos al final de su vida útil. Estudio de aplicación como dieléctrico
Marín Genescà, Marc; Mujal-Rosas, Ramon Maria; Garcia Amoros, Jordi; Massagués Vidal, Lluís; Pou Ibar, Josep Oriol; Colom Fajula, Xavier
El propósito del presente trabajo pasa por analizar la permitividad y el factor de pérdidas tanto del polietile-no de alta densidad (HD-PE), como del compuesto de matriz polimérica (HD-PE)reforzado con neumáticos fuera de uso (Ground Tire Rubber: GTR), con el fin de demostrar su viabilidad como material aislante eléc-trico (dieléctrico). Como es sabido, la incorporación de negro de humo en un polímero permite modificar su conductividad, y cómo el GTR lleva un porcentaje significativo de negro de humo, algunas de las pro-piedades eléctricas del nuevo compuesto cambiaran significativamente con respecto al polímero que es altamente aislante. El estudio se centrará, en un rango de frecuencias y temperaturas aptas para demostrar la viabilidad de este nuevo compuesto en usos indus-triales, enfocándolo principalmente en el análisis de la Permitividad, ya que es una propiedad clave para los condensadores. No obstante, también se caracterizará el comportamiento térmico y estructural, haciendo especial énfasis en el rango de trabajo del condensador (por debajo de los 100ºC). Finalmente, con el análisis estructural, se pretende contribuir al conocimiento de estos materiales compuestos provenientes de reciclaje, y así, aprovechar su potencial de reutilización, haciéndolos atractivos para las empresas interesadas en su relación rendimiento/precio.; The purpose of this work is to analyze the permittivity and the loss factor of both high-density polyethylene (HD-PE), as well as the polymer matrix composite (HD-PE) reinforced with end-of-life tires (Ground Tire Rubber: GTR), in order to demonstrate its viability as electrical insulating material (dielectric). As is known, the incorporation of carbon black in a polymer allows its conductivity to be modified, and since the GTR carries a significant percentage of carbon black, some of the electrical properties of the new compound will change significantly with respect to the polymer that is highly insulating. The study will focus on a range of frequencies and temperatures suitable to demonstrate the viability of this new composite in industrial uses, focusing mainly on the analysis of Permitivity, since it is a key property for capacitors. However, the thermal and structural behavior will also be characterized, with special emphasis on the capacitor working range (below 100ºC). Finally, with the structural analysis, it is inten-ded to contribute to the knowledge of these composite materials from recycling, and thus, take advantage of their potential for reuse, making them attractive for companies interested in their performance/price ratio.; El propòsit del present treball passa per analitzar la permitivitat i el factor de pèrdues tant del polietilè d'alta densitat (HD-PE), com del compost de matriu polimèrica (HD-PE) reforçat amb pneumàtics fora d'ús (Ground Tire Rubber: GTR ), amb la finalitat de demostrar la seva viabilitat com a material aïllant elèctric (dielèctric). Com és sabut, la incorporació de negre de fum en un polímer permet modificar la seva conductivitat, i com el GTR porta un percentatge sig-nificatiu de negre de fum, algunes de les propietats elèctriques del nou compost canvien significativament respecte del polímer, que és altament aïllant. L'estudi es centrarà, en un rang de freqüències i temperatures aptes per demostrar la viabilitat d'aquest nou compost en usos industrials, enfocant principalment en l'anàlisi de la Permitivitat, ja que és una propietat clau per als condensadors. No obstant això, també es caracteritzarà el comportament tèrmic i estructural, fent especial èmfasi en el rang de treball d’un condensador (per sota dels 100 º C). Finalment, amb l'anàlisi estructural, es pretén contribuir a el coneixement d'aquests materials compostos provinents de reciclatge, i així, aprofitar el seu potencial de reutilització, fent-los atractius per a les empreses interessades en la seva relació rendiment/preu.
2022-06-14T09:31:53Z
Marín Genescà, Marc
Mujal-Rosas, Ramon Maria
Garcia Amoros, Jordi
Massagués Vidal, Lluís
Pou Ibar, Josep Oriol
Colom Fajula, Xavier
El propósito del presente trabajo pasa por analizar la permitividad y el factor de pérdidas tanto del polietile-no de alta densidad (HD-PE), como del compuesto de matriz polimérica (HD-PE)reforzado con neumáticos fuera de uso (Ground Tire Rubber: GTR), con el fin de demostrar su viabilidad como material aislante eléc-trico (dieléctrico). Como es sabido, la incorporación de negro de humo en un polímero permite modificar su conductividad, y cómo el GTR lleva un porcentaje significativo de negro de humo, algunas de las pro-piedades eléctricas del nuevo compuesto cambiaran significativamente con respecto al polímero que es altamente aislante. El estudio se centrará, en un rango de frecuencias y temperaturas aptas para demostrar la viabilidad de este nuevo compuesto en usos indus-triales, enfocándolo principalmente en el análisis de la Permitividad, ya que es una propiedad clave para los condensadores. No obstante, también se caracterizará el comportamiento térmico y estructural, haciendo especial énfasis en el rango de trabajo del condensador (por debajo de los 100ºC). Finalmente, con el análisis estructural, se pretende contribuir al conocimiento de estos materiales compuestos provenientes de reciclaje, y así, aprovechar su potencial de reutilización, haciéndolos atractivos para las empresas interesadas en su relación rendimiento/precio.
The purpose of this work is to analyze the permittivity and the loss factor of both high-density polyethylene (HD-PE), as well as the polymer matrix composite (HD-PE) reinforced with end-of-life tires (Ground Tire Rubber: GTR), in order to demonstrate its viability as electrical insulating material (dielectric). As is known, the incorporation of carbon black in a polymer allows its conductivity to be modified, and since the GTR carries a significant percentage of carbon black, some of the electrical properties of the new compound will change significantly with respect to the polymer that is highly insulating. The study will focus on a range of frequencies and temperatures suitable to demonstrate the viability of this new composite in industrial uses, focusing mainly on the analysis of Permitivity, since it is a key property for capacitors. However, the thermal and structural behavior will also be characterized, with special emphasis on the capacitor working range (below 100ºC). Finally, with the structural analysis, it is inten-ded to contribute to the knowledge of these composite materials from recycling, and thus, take advantage of their potential for reuse, making them attractive for companies interested in their performance/price ratio.
El propòsit del present treball passa per analitzar la permitivitat i el factor de pèrdues tant del polietilè d'alta densitat (HD-PE), com del compost de matriu polimèrica (HD-PE) reforçat amb pneumàtics fora d'ús (Ground Tire Rubber: GTR ), amb la finalitat de demostrar la seva viabilitat com a material aïllant elèctric (dielèctric). Com és sabut, la incorporació de negre de fum en un polímer permet modificar la seva conductivitat, i com el GTR porta un percentatge sig-nificatiu de negre de fum, algunes de les propietats elèctriques del nou compost canvien significativament respecte del polímer, que és altament aïllant. L'estudi es centrarà, en un rang de freqüències i temperatures aptes per demostrar la viabilitat d'aquest nou compost en usos industrials, enfocant principalment en l'anàlisi de la Permitivitat, ja que és una propietat clau per als condensadors. No obstant això, també es caracteritzarà el comportament tèrmic i estructural, fent especial èmfasi en el rang de treball d’un condensador (per sota dels 100 º C). Finalment, amb l'anàlisi estructural, es pretén contribuir a el coneixement d'aquests materials compostos provinents de reciclatge, i així, aprofitar el seu potencial de reutilització, fent-los atractius per a les empreses interessades en la seva relació rendiment/preu.
External inertia emulation controller for grid-following power converter
Lai, Ngoc Bao
Tarraso Martínez, Andrés
Gregory Baltas, Nicholas
Marín Arévalo, Leonardo Vidal
Rodríguez Cortés, Pedro
http://hdl.handle.net/2117/358409
2023-11-26T03:28:56Z
2021-12-14T16:29:08Z
External inertia emulation controller for grid-following power converter
Lai, Ngoc Bao; Tarraso Martínez, Andrés; Gregory Baltas, Nicholas; Marín Arévalo, Leonardo Vidal; Rodríguez Cortés, Pedro
The advent of renewable energy has posed difficulties in the operation of power systems whose net inertia is becoming critically low. To face such challenges, grid-forming power has been one of the potential solutions pursued by the industry and research community. Although promising, grid-forming power converters are still immature for mass deployment in power systems. In the meanwhile, an enormous amount of grid-following power converters has been underexploited when it comes to grid-supporting functionalities. Therefore, this article proposes an external inertia emulation controller (eIEC) for grid-following power converter to provide frequency support to the grid. For the purpose of minimizing installation efforts and resources, the controller is designed in such a way that it can be implemented in an external controller communicating with the grid-following power converter via an industrial communication link. This article also investigates the effect of communication delay on the stability performance of the proposed controller. In addition to the detailed analysis, hardware-in-the-loop experiments are also carried out to validate the proposed eIEC.
2021-12-14T16:29:08Z
Lai, Ngoc Bao
Tarraso Martínez, Andrés
Gregory Baltas, Nicholas
Marín Arévalo, Leonardo Vidal
Rodríguez Cortés, Pedro
The advent of renewable energy has posed difficulties in the operation of power systems whose net inertia is becoming critically low. To face such challenges, grid-forming power has been one of the potential solutions pursued by the industry and research community. Although promising, grid-forming power converters are still immature for mass deployment in power systems. In the meanwhile, an enormous amount of grid-following power converters has been underexploited when it comes to grid-supporting functionalities. Therefore, this article proposes an external inertia emulation controller (eIEC) for grid-following power converter to provide frequency support to the grid. For the purpose of minimizing installation efforts and resources, the controller is designed in such a way that it can be implemented in an external controller communicating with the grid-following power converter via an industrial communication link. This article also investigates the effect of communication delay on the stability performance of the proposed controller. In addition to the detailed analysis, hardware-in-the-loop experiments are also carried out to validate the proposed eIEC.
Multi-rotor virtual machine for grid-forming converter to damp sub-synchronous resonances
Lai, Ngoc Bao
Gregory Baltas, Nicholas
Rodríguez Cortés, Pedro
http://hdl.handle.net/2117/358405
2022-04-17T04:56:07Z
2021-12-14T16:10:19Z
Multi-rotor virtual machine for grid-forming converter to damp sub-synchronous resonances
Lai, Ngoc Bao; Gregory Baltas, Nicholas; Rodríguez Cortés, Pedro
Grid-forming power converters (GFMC) have been widely adopted in power systems as an attractive solution against the challenges imposed by the ever-increasing penetration of renewables. Despite its versatility, GFMC is employed only to provide islanded operation, grid regulations, and synthetic inertia. To further extend the use of GFMC in enhancing power system stability, this paper proposes a multi-rotor virtual machine (MRVM) controller to attenuate sub-synchronous oscillations. Driven by the formulation of a virtual synchronous machine (VSM), the proposed MRVM implements a VSM-based GFMC with several virtual rotors whose electromechanical characteristics can be individually adjusted to target specific oscillatory modes in the system. In this work, the MRVM’s working principle is described in detail and tuning guidelines are proposed to simplify the selection of control parameters by using frequency-domain techniques and the eigenvalue locus analyses. To validate the performance of the MRVM, an IEEE benchmark grid model is adopted namely, the three-machine-infinite-bus system. It is evident from the results that the MRVM (i) provides higher degrees of freedom when dealing with sub-synchronous oscillations, and (ii) outperforms conventional GFMC, especially in damping intra-area power oscillations.
2021-12-14T16:10:19Z
Lai, Ngoc Bao
Gregory Baltas, Nicholas
Rodríguez Cortés, Pedro
Grid-forming power converters (GFMC) have been widely adopted in power systems as an attractive solution against the challenges imposed by the ever-increasing penetration of renewables. Despite its versatility, GFMC is employed only to provide islanded operation, grid regulations, and synthetic inertia. To further extend the use of GFMC in enhancing power system stability, this paper proposes a multi-rotor virtual machine (MRVM) controller to attenuate sub-synchronous oscillations. Driven by the formulation of a virtual synchronous machine (VSM), the proposed MRVM implements a VSM-based GFMC with several virtual rotors whose electromechanical characteristics can be individually adjusted to target specific oscillatory modes in the system. In this work, the MRVM’s working principle is described in detail and tuning guidelines are proposed to simplify the selection of control parameters by using frequency-domain techniques and the eigenvalue locus analyses. To validate the performance of the MRVM, an IEEE benchmark grid model is adopted namely, the three-machine-infinite-bus system. It is evident from the results that the MRVM (i) provides higher degrees of freedom when dealing with sub-synchronous oscillations, and (ii) outperforms conventional GFMC, especially in damping intra-area power oscillations.