PV-supercapacitor cascaded topology for primary frequency responses and dynamic inertia emulation
PV-supercapacitor cascaded topology for primary frequency responses and dynamic inertia emulation
Owing to rapid increase in PV penetration without inherent inertia, there has been an unremitting deterioration of the effective inertia of the existing power systems. This may pose a serious threat to the stability of power systems during disturbances if not taken care of. Hence, the problem of how to emulate Synthetic Inertia (SI) in PV Systems (PVS) to retain their frequency stability demands attention. Super Capacitor (SC)-based storage become an attractive option over the other energy storage types because of its high-power density, burst power handling capability, faster response and longer life cycle. Considering this, the authors here propose a novel PV-SC Cascaded Topology (PSCT) as a cost-effective approach to emulate SI by integrating a low voltage SC to a high voltage grid-connected PVS. The proposed PSCT helps in operating the SC as a voltage source rather than a current source. Thus, it eliminates the high gain requirements of the SC interfacing converters. The aim is to target two main frequency response services, i.e., Primary Frequency Response (PFR) and Synthetic Inertial Response (SIR), using a novel common control scheme, but without affecting any other energy intensive services. The authors introduced a Droop-Inspired (DI) method with an adjustable inertia constant to emulate dynamic inertia so that a wider range of Rate of Change of Frequency (RoCoF) values can be serviced with a limited storage. A very streamlined analysis was also carried out for sizing of the SC stage based on a simple Three-Point Linearization (TPL) technique and DI technique with a limited knowledge of the disturbance parameters. The whole system was initially validated in a MATLAB Simulink environment and later confirmed with the OPAL-RT Real-Time Simulator. The investigated response was subject to variation in terms of control parameters, changes in solar irradiance, grid frequency variation, etc.
Artificial inertia, Dynamic inertia emulation, Frequency response services, PV-SC series cascaded topology, RoCoF, Three-point linearization technique
Karpana, Sivakrishna
9532e5bb-ecf8-4af4-a617-57119f60d212
Batzelis, Efstratios
2a85086e-e403-443c-81a6-e3b4ee16ae5e
Maiti, Suman
af45e307-f55a-436c-b3d2-4de256c6a19a
Chakraborty, Chandan
6701fe34-862b-432b-bbe1-041a66e68938
10 December 2021
Karpana, Sivakrishna
9532e5bb-ecf8-4af4-a617-57119f60d212
Batzelis, Efstratios
2a85086e-e403-443c-81a6-e3b4ee16ae5e
Maiti, Suman
af45e307-f55a-436c-b3d2-4de256c6a19a
Chakraborty, Chandan
6701fe34-862b-432b-bbe1-041a66e68938
Karpana, Sivakrishna, Batzelis, Efstratios, Maiti, Suman and Chakraborty, Chandan
(2021)
PV-supercapacitor cascaded topology for primary frequency responses and dynamic inertia emulation.
Energies, 14 (24), [8347].
(doi:10.3390/en14248347).
Abstract
Owing to rapid increase in PV penetration without inherent inertia, there has been an unremitting deterioration of the effective inertia of the existing power systems. This may pose a serious threat to the stability of power systems during disturbances if not taken care of. Hence, the problem of how to emulate Synthetic Inertia (SI) in PV Systems (PVS) to retain their frequency stability demands attention. Super Capacitor (SC)-based storage become an attractive option over the other energy storage types because of its high-power density, burst power handling capability, faster response and longer life cycle. Considering this, the authors here propose a novel PV-SC Cascaded Topology (PSCT) as a cost-effective approach to emulate SI by integrating a low voltage SC to a high voltage grid-connected PVS. The proposed PSCT helps in operating the SC as a voltage source rather than a current source. Thus, it eliminates the high gain requirements of the SC interfacing converters. The aim is to target two main frequency response services, i.e., Primary Frequency Response (PFR) and Synthetic Inertial Response (SIR), using a novel common control scheme, but without affecting any other energy intensive services. The authors introduced a Droop-Inspired (DI) method with an adjustable inertia constant to emulate dynamic inertia so that a wider range of Rate of Change of Frequency (RoCoF) values can be serviced with a limited storage. A very streamlined analysis was also carried out for sizing of the SC stage based on a simple Three-Point Linearization (TPL) technique and DI technique with a limited knowledge of the disturbance parameters. The whole system was initially validated in a MATLAB Simulink environment and later confirmed with the OPAL-RT Real-Time Simulator. The investigated response was subject to variation in terms of control parameters, changes in solar irradiance, grid frequency variation, etc.
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energies-14-08347
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Accepted/In Press date: 30 October 2021
Published date: 10 December 2021
Additional Information:
Funding Information:
Funding: This research was supported by the Royal Academy of Engineering under the Engineering for Development Research Fellowship scheme (number RF/201819/18/86).
Publisher Copyright:
© 2021 by the authors. Licensee MDPI, Basel, Switzerland.
Keywords:
Artificial inertia, Dynamic inertia emulation, Frequency response services, PV-SC series cascaded topology, RoCoF, Three-point linearization technique
Identifiers
Local EPrints ID: 455882
URI: http://eprints.soton.ac.uk/id/eprint/455882
ISSN: 1996-1073
PURE UUID: 2d999492-5f90-4def-b985-cbd42da46ee1
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Date deposited: 07 Apr 2022 16:42
Last modified: 18 Mar 2024 04:01
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Contributors
Author:
Sivakrishna Karpana
Author:
Efstratios Batzelis
Author:
Suman Maiti
Author:
Chandan Chakraborty
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