Articles de revista
http://hdl.handle.net/2117/184797
2024-03-29T00:24:39Z
2024-03-29T00:24:39Z
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.
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 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.
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.
Enhanced performance controller for high power wind converters connected to weak grids
Shahparasti, Mahdi
Catalan, Pedro
García Quintanilla, José Ignacio
Candela García, José Ignacio
Tarraso Martínez, Andrés
Luna Alloza, Álvaro
http://hdl.handle.net/2117/358272
2022-05-17T12:26:38Z
2021-12-13T15:37:03Z
Enhanced performance controller for high power wind converters connected to weak grids
Shahparasti, Mahdi; Catalan, Pedro; García Quintanilla, José Ignacio; Candela García, José Ignacio; Tarraso Martínez, Andrés; Luna Alloza, Álvaro
This study proposes a control scheme for high power grid-connected wind power converters, which is oriented to enhance their performance when connected to weak grids with low short circuit ratio. The proposed controller consists of an outer current reference generation loop and an inner current loop, working in stationary reference frame. In the outer loop, the current reference is calculated to comply simultaneously with the grid code requirements, the control of the DC link, and the operational safety margins of the converter during faulty conditions. On the other hand, the proposed inner current loop consists of a proportional resonant controller, a capacitor voltage feedforward and a phase shifter. Moreover, simulation results considering different weak grid conditions, as well as experimental results of a full-scale 4 MW converter test-bench are presented to validate the good performance of the proposed method.
2021-12-13T15:37:03Z
Shahparasti, Mahdi
Catalan, Pedro
García Quintanilla, José Ignacio
Candela García, José Ignacio
Tarraso Martínez, Andrés
Luna Alloza, Álvaro
This study proposes a control scheme for high power grid-connected wind power converters, which is oriented to enhance their performance when connected to weak grids with low short circuit ratio. The proposed controller consists of an outer current reference generation loop and an inner current loop, working in stationary reference frame. In the outer loop, the current reference is calculated to comply simultaneously with the grid code requirements, the control of the DC link, and the operational safety margins of the converter during faulty conditions. On the other hand, the proposed inner current loop consists of a proportional resonant controller, a capacitor voltage feedforward and a phase shifter. Moreover, simulation results considering different weak grid conditions, as well as experimental results of a full-scale 4 MW converter test-bench are presented to validate the good performance of the proposed method.
Design of controller for virtual synchronous power plant
Tarraso Martínez, Andrés
Lai, Ngoc Bao
Verdugo Retamal, Cristian Andrés
Candela García, José Ignacio
Rodriguez, Pedro
http://hdl.handle.net/2117/357388
2022-04-17T05:55:15Z
2021-11-30T15:10:11Z
Design of controller for virtual synchronous power plant
Tarraso Martínez, Andrés; Lai, Ngoc Bao; Verdugo Retamal, Cristian Andrés; Candela García, José Ignacio; Rodriguez, Pedro
The increasing participation of renewables in power systems has forced system operators to strengthen grid codes requiring renewable power plants (RPPs) to provide fast frequency support such as inertia response and power oscillation damping. To cope with such new requirements, this article proposes the implementation of a virtual synchronous power plant controller (VSPPC) for RPPs. The VSPPC takes the most from emulating the behavior of a synchronous generator, especially in the case of grid events, as it permits emulating inertia and provides power oscillation damping capabilities. If compared with conventional control schemes, the main advantage of the VSPPC lays in the fact that it does not require to implement any modification in the existing controllers of the plant's converters, which are often controlled as grid-following generation units. This feature makes VSPPC attractive for incorporating advanced grid supporting functionalities in utility-scale RPPs. In this work, the main principles behind the VSPPC and comparative analysis based on simulation and experimental results are provided to validate its performance.
©2021 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.
2021-11-30T15:10:11Z
Tarraso Martínez, Andrés
Lai, Ngoc Bao
Verdugo Retamal, Cristian Andrés
Candela García, José Ignacio
Rodriguez, Pedro
The increasing participation of renewables in power systems has forced system operators to strengthen grid codes requiring renewable power plants (RPPs) to provide fast frequency support such as inertia response and power oscillation damping. To cope with such new requirements, this article proposes the implementation of a virtual synchronous power plant controller (VSPPC) for RPPs. The VSPPC takes the most from emulating the behavior of a synchronous generator, especially in the case of grid events, as it permits emulating inertia and provides power oscillation damping capabilities. If compared with conventional control schemes, the main advantage of the VSPPC lays in the fact that it does not require to implement any modification in the existing controllers of the plant's converters, which are often controlled as grid-following generation units. This feature makes VSPPC attractive for incorporating advanced grid supporting functionalities in utility-scale RPPs. In this work, the main principles behind the VSPPC and comparative analysis based on simulation and experimental results are provided to validate its performance.
Quadrature voltage compensation in the isolated multi-modular converter
Verdugo Retamal, Cristian Andrés
Candela García, José Ignacio
Rodríguez Cortés, Pedro
http://hdl.handle.net/2117/355838
2022-05-17T10:21:32Z
2021-11-09T10:13:04Z
Quadrature voltage compensation in the isolated multi-modular converter
Verdugo Retamal, Cristian Andrés; Candela García, José Ignacio; Rodríguez Cortés, Pedro
Series connections of modules in cascaded multilevel converters are prone to power imbalances due to voltage differences on their DC side. When modules are connected to direct current (DC) sources, such as photovoltaic panels, the capability of withstanding power imbalances is crucial for generating the maximum power. In order to provide a possible solution for this requirement, this paper proposes a control strategy called Quadrature Voltage Compensation, which allows a wide range of power imbalances. The proposed control strategy regulates the power by introducing a circulating current between the arms and a phase angle in the output voltage. The impact of the circulating current and its effect on the phase voltage are studied. To highlight the features of the proposed strategy, an analytical model based on vector superposition is also described, demonstrating the strong capability of tolerating power differences. Finally, to validate the effectiveness of the Quadrature Voltage Compensation, simulation and experimental results are presented for a three-phase isolated multi-modular converter.
2021-11-09T10:13:04Z
Verdugo Retamal, Cristian Andrés
Candela García, José Ignacio
Rodríguez Cortés, Pedro
Series connections of modules in cascaded multilevel converters are prone to power imbalances due to voltage differences on their DC side. When modules are connected to direct current (DC) sources, such as photovoltaic panels, the capability of withstanding power imbalances is crucial for generating the maximum power. In order to provide a possible solution for this requirement, this paper proposes a control strategy called Quadrature Voltage Compensation, which allows a wide range of power imbalances. The proposed control strategy regulates the power by introducing a circulating current between the arms and a phase angle in the output voltage. The impact of the circulating current and its effect on the phase voltage are studied. To highlight the features of the proposed strategy, an analytical model based on vector superposition is also described, demonstrating the strong capability of tolerating power differences. Finally, to validate the effectiveness of the Quadrature Voltage Compensation, simulation and experimental results are presented for a three-phase isolated multi-modular converter.
Control and validation of a reinforced power conversion system for upcoming bioelectrochemical power to gas stations
Shahparasti, Mahdi
Rajaei, Amirhossein
Tarraso Martínez, Andrés
Vidal León Romay, José David
Luna, Alvaro
http://hdl.handle.net/2117/353003
2023-10-22T04:16:21Z
2021-10-05T11:45:04Z
Control and validation of a reinforced power conversion system for upcoming bioelectrochemical power to gas stations
Shahparasti, Mahdi; Rajaei, Amirhossein; Tarraso Martínez, Andrés; Vidal León Romay, José David; Luna, Alvaro
This paper presents a proposal for potential bioelectrochemical power to gas stations. It consists of a two-level voltage source converter interfacing the electrical grid on the AC side and an electromethanogenesis based bioelectrochemical system (EMG-BES) working as a stacked module on the DC side. The proposed system converts CO2 and electrical energy into methane, using wastewater as the additional chemical energy input. This energy storage system can contribute to dampening the variability of renewables in the electrical network, provide even flexibility and grid services by controlling the active and reactive power exchanged and is an interesting alternative technology in the market of energy storage for big energy applications. The big challenge for controlling this system lays in the fact that the DC bus voltage of the converter has to be changed in order to regulate the exchanged active power with the grid. This paper presents a cascade approach to control such a system by means of combining external control loops with fast inner loops. The outer power loop, with a proportional-integral (PI) controller with special limitation values and anti-windup capability, is used to generate DC bus voltage reference. An intermediate loop is used for DC bus voltage regulation and current reference generation. A new proportional resonant controller is used to track the current reference. The proposed scheme has been validated through realtime simulation in OPAL OP4510.
2021-10-05T11:45:04Z
Shahparasti, Mahdi
Rajaei, Amirhossein
Tarraso Martínez, Andrés
Vidal León Romay, José David
Luna, Alvaro
This paper presents a proposal for potential bioelectrochemical power to gas stations. It consists of a two-level voltage source converter interfacing the electrical grid on the AC side and an electromethanogenesis based bioelectrochemical system (EMG-BES) working as a stacked module on the DC side. The proposed system converts CO2 and electrical energy into methane, using wastewater as the additional chemical energy input. This energy storage system can contribute to dampening the variability of renewables in the electrical network, provide even flexibility and grid services by controlling the active and reactive power exchanged and is an interesting alternative technology in the market of energy storage for big energy applications. The big challenge for controlling this system lays in the fact that the DC bus voltage of the converter has to be changed in order to regulate the exchanged active power with the grid. This paper presents a cascade approach to control such a system by means of combining external control loops with fast inner loops. The outer power loop, with a proportional-integral (PI) controller with special limitation values and anti-windup capability, is used to generate DC bus voltage reference. An intermediate loop is used for DC bus voltage regulation and current reference generation. A new proportional resonant controller is used to track the current reference. The proposed scheme has been validated through realtime simulation in OPAL OP4510.
AI-based damping of electromechanical oscillations by using grid-connected converter
Gregory Baltas, Nicholas
Lai, Ngoc Bao
Tarraso Martínez, Andrés
Marín Arévalo, Leonardo Vidal
Blaabjerg, Frede
Rodríguez Cortés, Pedro
http://hdl.handle.net/2117/352999
2023-11-26T06:58:53Z
2021-10-05T10:57:54Z
AI-based damping of electromechanical oscillations by using grid-connected converter
Gregory Baltas, Nicholas; Lai, Ngoc Bao; Tarraso Martínez, Andrés; Marín Arévalo, Leonardo Vidal; Blaabjerg, Frede; Rodríguez Cortés, Pedro
The proliferation of grid-connected converter interfaced energy sources in Smart Grids, enhance sustainability and efficiency as well as minimizing power losses and costs. However, concerns arise regarding the stability and reliability of future smart grids due to this wide integration of power electronic devices, which are recognized to affect the dynamic response of the system, especially during disturbances. For instance, apart from the lower damping of existing electromechanical modes, new low-frequency oscillations begin to appear. Yet, the ability of grid-connected converters to provide grid support functionalities can alleviate the aforementioned challenges. Relevant studies show that these functionalities can be enhanced even further, if information regarding the oscillation characteristics are available. Traditional methods for extracting modal information are very well suited for monitoring purposes, however, they pose certain limitations when considered for control applications. Therefore, this paper proposes a multi-band intelligent power oscillation damper (MiPOD) that exploits 1) the inherent characteristics of grid-connected converters to damp multiple power oscillations and 2) the modeling capabilities of Artificial Intelligence (AI) for predicting the frequency of electromechanical oscillations in the system, as operating conditions change. Essentially, the MiPOD integrates the AI model in the control loop of the converter to attenuate multiple modes of oscillation. The proposed controller is validated for different disturbances and randomly generated operating points in the two area system. Specifically, in this case the AI model is a Random Forest ensemble regressor that is developed for tracking two electromechanical modes. As it is shown, the MiPOD can improve the overall performance of the system under various contingency scenarios with only 6% of the corresponding total nominal capacity of synchronous generators. In addition, the monitoring and damping abilities of the MiPOD are demonstrated for a vast range of operating points just by tuning two parameters; the predicted oscillation frequencies of the local and inter-area mode.
2021-10-05T10:57:54Z
Gregory Baltas, Nicholas
Lai, Ngoc Bao
Tarraso Martínez, Andrés
Marín Arévalo, Leonardo Vidal
Blaabjerg, Frede
Rodríguez Cortés, Pedro
The proliferation of grid-connected converter interfaced energy sources in Smart Grids, enhance sustainability and efficiency as well as minimizing power losses and costs. However, concerns arise regarding the stability and reliability of future smart grids due to this wide integration of power electronic devices, which are recognized to affect the dynamic response of the system, especially during disturbances. For instance, apart from the lower damping of existing electromechanical modes, new low-frequency oscillations begin to appear. Yet, the ability of grid-connected converters to provide grid support functionalities can alleviate the aforementioned challenges. Relevant studies show that these functionalities can be enhanced even further, if information regarding the oscillation characteristics are available. Traditional methods for extracting modal information are very well suited for monitoring purposes, however, they pose certain limitations when considered for control applications. Therefore, this paper proposes a multi-band intelligent power oscillation damper (MiPOD) that exploits 1) the inherent characteristics of grid-connected converters to damp multiple power oscillations and 2) the modeling capabilities of Artificial Intelligence (AI) for predicting the frequency of electromechanical oscillations in the system, as operating conditions change. Essentially, the MiPOD integrates the AI model in the control loop of the converter to attenuate multiple modes of oscillation. The proposed controller is validated for different disturbances and randomly generated operating points in the two area system. Specifically, in this case the AI model is a Random Forest ensemble regressor that is developed for tracking two electromechanical modes. As it is shown, the MiPOD can improve the overall performance of the system under various contingency scenarios with only 6% of the corresponding total nominal capacity of synchronous generators. In addition, the monitoring and damping abilities of the MiPOD are demonstrated for a vast range of operating points just by tuning two parameters; the predicted oscillation frequencies of the local and inter-area mode.