Smart Hybrid AC/DC Microgrids

Smart Hybrid AC/DC Microgrids

Author: Yunwei Ryan Li

Publisher: John Wiley & Sons

Published: 2022-09-06

Total Pages: 420

ISBN-13: 1119598370

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SMART HYBRID AC/DC MICROGRIDS Addresses the technical aspects and implementation challenges of smart hybrid AC/DC microgrids Hybrid AC/DC Microgrids: Power Management, Energy Management, and Power Quality Control provides comprehensive coverage of interconnected smart hybrid microgrids, their different structures, and the technical issues associated with their control and implementation in the next generation of smart grids. This authoritative single-volume resource addresses smart hybrid microgrids power management, energy management, communications, power converter control, power quality, renewable generation integration, energy storage, and more. The book contains both basic and advanced technical information about smart hybrid AC/DC microgrids, featuring a detailed discussion of microgrid structures, communication technologies, and various configurations of interfacing power converters and control strategies. Numerous case studies highlight effective solutions for critical issues in hybrid microgrid operation, control and power quality compensation throughout the text. Topics include control strategies of renewable energy and energy storage interfacing converters in hybrid microgrids, supervisory control strategies of interfacing power converters for microgrid power management and energy microgrid, and smart interfacing power converters for power quality control. This volume: Includes a thorough overview of hybrid AC/DC microgrid concepts, structures, and applications Discusses communication and security enhancement techniques for guarding against cyberattacks Provides detailed controls of smart interfacing power electronics converters from distributed generations and energy storage systems in hybrid AC/DC microgrids Provides details on transient and steady-state power management systems in microgrids Discusses energy management systems, hierarchical control, multi-agent control, and advanced distribution management control of smart microgrids Identifies opportunities to control power quality with smart interfacing power electronic converters Addresses power quality issues in the context of real-world applications in data centers, electric railway systems, and electric vehicle charging stations Smart Hybrid AC/DC Microgrids: Power Management, Energy Management, and Power Quality Control is a valuable source of up-to-date information for senior undergraduate and graduate students as well as academic researchers and industry engineers in the areas of renewable energy, smart grids, microgrids, and power electronics.


Book Synopsis Smart Hybrid AC/DC Microgrids by : Yunwei Ryan Li

Download or read book Smart Hybrid AC/DC Microgrids written by Yunwei Ryan Li and published by John Wiley & Sons. This book was released on 2022-09-06 with total page 420 pages. Available in PDF, EPUB and Kindle. Book excerpt: SMART HYBRID AC/DC MICROGRIDS Addresses the technical aspects and implementation challenges of smart hybrid AC/DC microgrids Hybrid AC/DC Microgrids: Power Management, Energy Management, and Power Quality Control provides comprehensive coverage of interconnected smart hybrid microgrids, their different structures, and the technical issues associated with their control and implementation in the next generation of smart grids. This authoritative single-volume resource addresses smart hybrid microgrids power management, energy management, communications, power converter control, power quality, renewable generation integration, energy storage, and more. The book contains both basic and advanced technical information about smart hybrid AC/DC microgrids, featuring a detailed discussion of microgrid structures, communication technologies, and various configurations of interfacing power converters and control strategies. Numerous case studies highlight effective solutions for critical issues in hybrid microgrid operation, control and power quality compensation throughout the text. Topics include control strategies of renewable energy and energy storage interfacing converters in hybrid microgrids, supervisory control strategies of interfacing power converters for microgrid power management and energy microgrid, and smart interfacing power converters for power quality control. This volume: Includes a thorough overview of hybrid AC/DC microgrid concepts, structures, and applications Discusses communication and security enhancement techniques for guarding against cyberattacks Provides detailed controls of smart interfacing power electronics converters from distributed generations and energy storage systems in hybrid AC/DC microgrids Provides details on transient and steady-state power management systems in microgrids Discusses energy management systems, hierarchical control, multi-agent control, and advanced distribution management control of smart microgrids Identifies opportunities to control power quality with smart interfacing power electronic converters Addresses power quality issues in the context of real-world applications in data centers, electric railway systems, and electric vehicle charging stations Smart Hybrid AC/DC Microgrids: Power Management, Energy Management, and Power Quality Control is a valuable source of up-to-date information for senior undergraduate and graduate students as well as academic researchers and industry engineers in the areas of renewable energy, smart grids, microgrids, and power electronics.

Risk-Based Energy Management

Risk-Based Energy Management

Author: Sayyad Nojavan

Publisher: Academic Press

Published: 2019-07-20

Total Pages: 294

ISBN-13: 0128174927

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Risk-Based Energy Management: DC, AC and Hybrid AC-DC Microgrids defines the problems and challenges of DC, AC and hybrid AC-DC microgrids and considers the right tactics and risk-based scheduling to tackle them. The book looks at the intermittent nature of renewable generation, demand and market price with the risk to DC, AC and hybrid AC-DC microgrids, which makes it relevant for anyone in renewable energy demand and supply. As utilization of distributed energy resources and the intermittent nature of renewable generations, demand and market price can put the operation of DC, AC and hybrid AC-DC microgrids at risk, this book presents a timely resource. Discusses both the challenges and solutions surrounding DC, AC and hybrid AC-DC microgrids Proposes robust scheduling of DC, AC and hybrid AC-DC microgrids under uncertain environments Includes modeling upstream grid prices, renewable resources and intermittent load in the decision-making process of DC, AC and hybrid AC-DC microgrids


Book Synopsis Risk-Based Energy Management by : Sayyad Nojavan

Download or read book Risk-Based Energy Management written by Sayyad Nojavan and published by Academic Press. This book was released on 2019-07-20 with total page 294 pages. Available in PDF, EPUB and Kindle. Book excerpt: Risk-Based Energy Management: DC, AC and Hybrid AC-DC Microgrids defines the problems and challenges of DC, AC and hybrid AC-DC microgrids and considers the right tactics and risk-based scheduling to tackle them. The book looks at the intermittent nature of renewable generation, demand and market price with the risk to DC, AC and hybrid AC-DC microgrids, which makes it relevant for anyone in renewable energy demand and supply. As utilization of distributed energy resources and the intermittent nature of renewable generations, demand and market price can put the operation of DC, AC and hybrid AC-DC microgrids at risk, this book presents a timely resource. Discusses both the challenges and solutions surrounding DC, AC and hybrid AC-DC microgrids Proposes robust scheduling of DC, AC and hybrid AC-DC microgrids under uncertain environments Includes modeling upstream grid prices, renewable resources and intermittent load in the decision-making process of DC, AC and hybrid AC-DC microgrids

Toward the Integration of DC Microgrids Into a Hybrid AC/DC Paradigm

Toward the Integration of DC Microgrids Into a Hybrid AC/DC Paradigm

Author: Amr Abdelnaeem Ismail Said

Publisher:

Published: 2016

Total Pages: 120

ISBN-13:

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The recent penetration of distributed generation (DG) into existing electricity grids and the consequent development of active distribution networks (ADNs) have prompted an exploration of power distribution in a dc microgrid paradigm. Although dc power distribution has been implemented in aircraft, ships, and communication centres, the technology is still at an early stage and must be investigated with respect to technical feasibility when applied to distribution systems. In particular, the operation of a dc microgrid in both grid-connected and islanded modes and its integration into an existing ac infrastructure are subject to significant challenges that impede the practical realization of dc microgrids. On one hand, because the dc voltage profile is coupled with the injected active power at the system buses, it is seriously influenced by the intermittent nature of renewable resources such as solar and wind energy. In islanded operating mode, the presence of system resistance leads to a further trade-off between an appropriate system voltage profile and a precise power management scheme. On the other hand, the development of hybrid ac/dc microgrids introduces a fresh operational philosophy that enhances power sharing among ac and dc subgrids through the coupling of ac and dc steady-state variables. With these challenges as motivation, the primary goal of this thesis was to develop effective power management schemes and a steady-state analysis tool that can enable the reliable integration of dc microgrids into a smart hybrid ac/dc paradigm. Achieving this objective entailed the completion of three core studies: 1) the introduction of a robust control scheme for mitigating voltage regulation challenges associated with dc distribution systems (DCDSs) that are characterized by a high penetration of distributed and renewable generation, 2) the proposal of a supervisory control strategy for precise DG output power allocation that is based on DG rating and operational costs yet guarantees an appropriate voltage profile for islanded dc microgrids, 3) the development of an accurate and comprehensive power flow algorithm for analyzing the steady-state behaviour of islanded hybrid ac/dc microgrids, and 4) the optimization of hybrid ac/dc microgrids configuration. As the first research component, a novel multi-agent control scheme has been developed for regulating the voltage profile of DCDSs that incorporate a large number of intermittent energy sources. The proposed control scheme consists of two sequential stages. In the first stage, a distributed state estimation algorithm is implemented to estimate the voltage profile in DCDSs, thus enhancing the interlinking converter (IC) operation in regulating the system voltages within specified limits. If the IC alone fails to regulate the system voltages, a second control stage is activated and executed through either equal or optimum curtailment strategy of the DG output power. A variety of case studies have been conducted in order to demonstrate the effectiveness, robustness, and convergence characteristics of the control schemes that have been developed. The second element of this research is a multi-agent supervisory control that has been created in order to provide precise power management in isolated DC microgrids. Two aspects of power management have been considered: 1) equal power sharing, which has been realized via a proposed distributed equal power sharing (DEPS) algorithm, and 2) optimal power dispatch, which has been achieved through a proposed distributed equal incremental cost (DEIC) algorithm. Both algorithms offer the additional advantage of affording the ability to restore the average system voltage to its nominal value. Real-time OPAL-RT simulations have demonstrated the effectiveness of the developed algorithms in a hardware-in-the-loop (HIL) application. The third part of the research has introduced a sequential power flow algorithm for hybrid ac/dc microgrids operating in islanded mode. In contrast to the conditions in grid-connected systems, variable rather than fixed ac frequencies and dc voltages are utilized for coordinating power between the ac and dc microgrids. The primary challenge is to solve the power flow problem in hybrid microgrids in a manner that includes consideration of both the absence of a slack bus and the coupling between the frequency and dc voltage though ICs. In the proposed algorithm, the ac power flow is solved using the Newton-Raphson (NR) method, thereby updating the ac variables and utilizing them accordingly in a proposed IC model for solving the dc problem. This sequential algorithm is iterated until convergence. The accuracy of the algorithm has been verified through detailed time-domain simulations using PSCAD/EMTDC, and its robustness and computational cost compare favourable with those of conventional algorithms. The final part highlights the implementation of the developed steady-state models in obtaining an optimum hybrid microgrid configuration. The system configuration could be manipulated by changing the DG droop settings as well as the network topological structure. The contribution of both approaches has been investigated, through an optimum power flow (OPF) formulation, in improving the system loadability as the primary measure of the hybrid microgrid performance.


Book Synopsis Toward the Integration of DC Microgrids Into a Hybrid AC/DC Paradigm by : Amr Abdelnaeem Ismail Said

Download or read book Toward the Integration of DC Microgrids Into a Hybrid AC/DC Paradigm written by Amr Abdelnaeem Ismail Said and published by . This book was released on 2016 with total page 120 pages. Available in PDF, EPUB and Kindle. Book excerpt: The recent penetration of distributed generation (DG) into existing electricity grids and the consequent development of active distribution networks (ADNs) have prompted an exploration of power distribution in a dc microgrid paradigm. Although dc power distribution has been implemented in aircraft, ships, and communication centres, the technology is still at an early stage and must be investigated with respect to technical feasibility when applied to distribution systems. In particular, the operation of a dc microgrid in both grid-connected and islanded modes and its integration into an existing ac infrastructure are subject to significant challenges that impede the practical realization of dc microgrids. On one hand, because the dc voltage profile is coupled with the injected active power at the system buses, it is seriously influenced by the intermittent nature of renewable resources such as solar and wind energy. In islanded operating mode, the presence of system resistance leads to a further trade-off between an appropriate system voltage profile and a precise power management scheme. On the other hand, the development of hybrid ac/dc microgrids introduces a fresh operational philosophy that enhances power sharing among ac and dc subgrids through the coupling of ac and dc steady-state variables. With these challenges as motivation, the primary goal of this thesis was to develop effective power management schemes and a steady-state analysis tool that can enable the reliable integration of dc microgrids into a smart hybrid ac/dc paradigm. Achieving this objective entailed the completion of three core studies: 1) the introduction of a robust control scheme for mitigating voltage regulation challenges associated with dc distribution systems (DCDSs) that are characterized by a high penetration of distributed and renewable generation, 2) the proposal of a supervisory control strategy for precise DG output power allocation that is based on DG rating and operational costs yet guarantees an appropriate voltage profile for islanded dc microgrids, 3) the development of an accurate and comprehensive power flow algorithm for analyzing the steady-state behaviour of islanded hybrid ac/dc microgrids, and 4) the optimization of hybrid ac/dc microgrids configuration. As the first research component, a novel multi-agent control scheme has been developed for regulating the voltage profile of DCDSs that incorporate a large number of intermittent energy sources. The proposed control scheme consists of two sequential stages. In the first stage, a distributed state estimation algorithm is implemented to estimate the voltage profile in DCDSs, thus enhancing the interlinking converter (IC) operation in regulating the system voltages within specified limits. If the IC alone fails to regulate the system voltages, a second control stage is activated and executed through either equal or optimum curtailment strategy of the DG output power. A variety of case studies have been conducted in order to demonstrate the effectiveness, robustness, and convergence characteristics of the control schemes that have been developed. The second element of this research is a multi-agent supervisory control that has been created in order to provide precise power management in isolated DC microgrids. Two aspects of power management have been considered: 1) equal power sharing, which has been realized via a proposed distributed equal power sharing (DEPS) algorithm, and 2) optimal power dispatch, which has been achieved through a proposed distributed equal incremental cost (DEIC) algorithm. Both algorithms offer the additional advantage of affording the ability to restore the average system voltage to its nominal value. Real-time OPAL-RT simulations have demonstrated the effectiveness of the developed algorithms in a hardware-in-the-loop (HIL) application. The third part of the research has introduced a sequential power flow algorithm for hybrid ac/dc microgrids operating in islanded mode. In contrast to the conditions in grid-connected systems, variable rather than fixed ac frequencies and dc voltages are utilized for coordinating power between the ac and dc microgrids. The primary challenge is to solve the power flow problem in hybrid microgrids in a manner that includes consideration of both the absence of a slack bus and the coupling between the frequency and dc voltage though ICs. In the proposed algorithm, the ac power flow is solved using the Newton-Raphson (NR) method, thereby updating the ac variables and utilizing them accordingly in a proposed IC model for solving the dc problem. This sequential algorithm is iterated until convergence. The accuracy of the algorithm has been verified through detailed time-domain simulations using PSCAD/EMTDC, and its robustness and computational cost compare favourable with those of conventional algorithms. The final part highlights the implementation of the developed steady-state models in obtaining an optimum hybrid microgrid configuration. The system configuration could be manipulated by changing the DG droop settings as well as the network topological structure. The contribution of both approaches has been investigated, through an optimum power flow (OPF) formulation, in improving the system loadability as the primary measure of the hybrid microgrid performance.

Microgrids

Microgrids

Author: Sanjeevikumar Padmanaban

Publisher: CRC Press

Published: 2020-11-24

Total Pages: 94

ISBN-13: 1000226891

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Microgrids offers a complete discussion and details about microgrids and their applications, including modeling of AC/DC and hybrid grids in a tied mode with simulation for the solar systems, wind turbines, biomass and fuel cells, and deployment issues. The data communications and control mechanism implementations are analyzed for proper coordination of the AC/DC microgrid. The various real-time applications and future development of the microgrid are also discussed in this book, with MATLAB®-based simulations and results. This book: Discusses the fundamentals of microgrids, the components of microgrids, the modeling of renewable energy sources, and the implementation of microgrids. Explores AC and DC microgrid modeling with real-time examples. Examines the effective extraction of energy from renewable energy sources. Covers analysis of data communications and control-mechanism implementations. Includes HOMER/MATLAB®-based simulations and results on microgrids. This book would be a welcome addition to the libraries of researchers, senior undergraduate students, and graduate students in power and electrical engineering, especially those working with smart and microgrids.


Book Synopsis Microgrids by : Sanjeevikumar Padmanaban

Download or read book Microgrids written by Sanjeevikumar Padmanaban and published by CRC Press. This book was released on 2020-11-24 with total page 94 pages. Available in PDF, EPUB and Kindle. Book excerpt: Microgrids offers a complete discussion and details about microgrids and their applications, including modeling of AC/DC and hybrid grids in a tied mode with simulation for the solar systems, wind turbines, biomass and fuel cells, and deployment issues. The data communications and control mechanism implementations are analyzed for proper coordination of the AC/DC microgrid. The various real-time applications and future development of the microgrid are also discussed in this book, with MATLAB®-based simulations and results. This book: Discusses the fundamentals of microgrids, the components of microgrids, the modeling of renewable energy sources, and the implementation of microgrids. Explores AC and DC microgrid modeling with real-time examples. Examines the effective extraction of energy from renewable energy sources. Covers analysis of data communications and control-mechanism implementations. Includes HOMER/MATLAB®-based simulations and results on microgrids. This book would be a welcome addition to the libraries of researchers, senior undergraduate students, and graduate students in power and electrical engineering, especially those working with smart and microgrids.

Integration of AC/DC Microgrids into Power Grids

Integration of AC/DC Microgrids into Power Grids

Author: Fazel Mohammadi

Publisher: MDPI

Published: 2020-12-02

Total Pages: 154

ISBN-13: 3039361805

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AC/DC Microgrids are a small part of low voltage distribution networks that are located far from power substations, and are interconnected through the point of common coupling to power grids. These systems are important keys for the flexible, techno-economic, and environmental-friendly generation of units for the reliable operation and cost-effective planning of smart electricity grids. Although AC/DC microgrids, with the integration of renewable energy resources and other energy systems, such as power-to-gas, combined heat and power, combined cooling heat and power, power-to-heat, power-to-vehicle, pump and compressed air storage, have several advantages, there are some technical aspects that must be addressed. This Special Issue aims to study the configuration, impacts, and prospects of AC/DC microgrids that enable enhanced solutions for intelligent and optimized electricity systems, energy storage systems, and demand-side management in power grids with an increasing share of distributed energy resources. It includes AC/DC microgrid modeling, simulation, control, operation, protection, dynamics, planning, reliability and security, as well as considering power quality improvement, load forecasting, market operations, energy conversion, cyber/physical security, supervisory and monitoring, diagnostics and prognostics systems.


Book Synopsis Integration of AC/DC Microgrids into Power Grids by : Fazel Mohammadi

Download or read book Integration of AC/DC Microgrids into Power Grids written by Fazel Mohammadi and published by MDPI. This book was released on 2020-12-02 with total page 154 pages. Available in PDF, EPUB and Kindle. Book excerpt: AC/DC Microgrids are a small part of low voltage distribution networks that are located far from power substations, and are interconnected through the point of common coupling to power grids. These systems are important keys for the flexible, techno-economic, and environmental-friendly generation of units for the reliable operation and cost-effective planning of smart electricity grids. Although AC/DC microgrids, with the integration of renewable energy resources and other energy systems, such as power-to-gas, combined heat and power, combined cooling heat and power, power-to-heat, power-to-vehicle, pump and compressed air storage, have several advantages, there are some technical aspects that must be addressed. This Special Issue aims to study the configuration, impacts, and prospects of AC/DC microgrids that enable enhanced solutions for intelligent and optimized electricity systems, energy storage systems, and demand-side management in power grids with an increasing share of distributed energy resources. It includes AC/DC microgrid modeling, simulation, control, operation, protection, dynamics, planning, reliability and security, as well as considering power quality improvement, load forecasting, market operations, energy conversion, cyber/physical security, supervisory and monitoring, diagnostics and prognostics systems.

The New AC/DC Hybrid Microgrid Paradigm

The New AC/DC Hybrid Microgrid Paradigm

Author: Abdelsalam Eajal

Publisher:

Published: 2018

Total Pages: 166

ISBN-13:

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AC/DC hybrid microgrids (HMGs) represent a promising architecture that allows the hosting of innovative dc energy resources, such as renewables, and modern dc loads, such as electric vehicles, thereby reducing the number of conversion stages and offering other technical and cost benefits. Such advantages have prompted power distribution planners to begin investigating the possibility of hybridizing existing ac grids and designing new ac/dc hybrid clusters, referred to as microgrids, as a step toward an envisioned smart grid that incorporates multiple ac/dc microgrids characterized by "plug-and-play" features. Despite their potential, when either islanded or interfaced with the main grid, HMGs create challenges with respect to system operation and control, such as difficulties related to precise power sharing, voltage stability during a contingency, the control and management of power transfer through the interlinking converters (ICs), and the coordination of local distributed energy resources (DERs) with the hosting main grid. An understanding of HMGs and their operational philosophy during islanding will assuredly pave the way toward the realization of a future smart grid that includes a plug-and-play feature and will alleviate any operational challenges. However, the planning and operation of such islanded and hybrid systems are reliant on a powerful and efficient power flow analysis tool. To this end, this thesis introduces a novel unified, generic, flexible power flow algorithm for islanded/isolated HMGs. The developed algorithm is generic in the sense that it includes consideration of the unique characteristics of islanded HMGs: a variety of possible topologies, droop controllability of the DERs and bidirectionality of the power flow in the ICs. The new power flow formulation is flexible and permits the easy incorporation of any changes in the DER operating modes and the IC control schemes. The developed algorithm was validated against a detailed time-domain model and applied for the analysis of a variety of operational and control aspects in islanded HMGs, including the problem of imprecise power sharing and droop control of the ICs. The proposed load flow program can form the basis of and provide direction for further studies of islanded HMGs. This thesis also presents a deeper look at the problem of inaccurate active and reactive power sharing in islanded droop-based HMGs and proposes a unified and universal power sharing scheme that can simultaneously ensure precise power sharing in both ac and dc subgrids. Test results demonstrate the capability of the developed scheme with respect to achieving exact power sharing not only among DERs in proportion to their ratings but also among ICs that interface adjacent ac and dc microgrids. The developed unified power sharing scheme would assist system planners with the effective design of droop characteristics for DERs and ICs, which would result in enhancements such as the avoidance of converter overloading and the achievement of precise load sharing. Another operational aspect that was thoroughly investigated for this thesis is the possibility of voltage instability/collapse in islanded HMGs during contingencies. This research unveiled the possibility of voltage instability in HMGs that include constant power loads and a mix of synchronous-based and converter-based generating units. As indicated by the voltage stability analysis presented here, despite the fact that healthy microgrids have far-reaching loadability boundaries, the voltage at some ac/dc load buses can unexpectedly collapse during abnormal conditions. The analysis also revealed that fine tuning the droop characteristics of DERs and ICs can enlarge the voltage stability margin and safeguard the entire microgrid against collapse during contingencies, all without the sacrifice of a single load. A final component of this thesis is the proposal of a two-stage stochastic centralized dispatch scheme for ac/dc hybrid distribution systems. The developed dispatch scheme coordinates the operation of a variety of DERs, such as distributed generators and energy storage systems. It also ensures the coordinated charging of electric vehicles and models the degradation of their batteries that occurs due to the vehicle-to-grid action. The energy coordination problem has been formulated as a two-stage day-ahead resource scheduling problem: the intermittent supply; the variable demand, which includes electric vehicles; and the fluctuating real-time energy price are all modelled as random variables. The first stage produces day-ahead dispatch decisions for the dispatchable DG units. For a set of possible scenarios over the next 24 h, the second stage determines appropriate corrective decisions with respect to the import/export schedule, storage charging/discharging cycles, and electric vehicle charging/discharging patterns. The simulation results demonstrate the effectiveness of the developed scheme for optimally coordinating the various components of future ac/dc hybrid smart grids. Despite its substantial merits and value as a host for ac and dc technologies, a smart grid with HMGs creates previously unexperienced operational challenges for system planners and operators. The work completed for this thesis could help pave the way for the realization of ac/dc hybrid smart grids in years to come.


Book Synopsis The New AC/DC Hybrid Microgrid Paradigm by : Abdelsalam Eajal

Download or read book The New AC/DC Hybrid Microgrid Paradigm written by Abdelsalam Eajal and published by . This book was released on 2018 with total page 166 pages. Available in PDF, EPUB and Kindle. Book excerpt: AC/DC hybrid microgrids (HMGs) represent a promising architecture that allows the hosting of innovative dc energy resources, such as renewables, and modern dc loads, such as electric vehicles, thereby reducing the number of conversion stages and offering other technical and cost benefits. Such advantages have prompted power distribution planners to begin investigating the possibility of hybridizing existing ac grids and designing new ac/dc hybrid clusters, referred to as microgrids, as a step toward an envisioned smart grid that incorporates multiple ac/dc microgrids characterized by "plug-and-play" features. Despite their potential, when either islanded or interfaced with the main grid, HMGs create challenges with respect to system operation and control, such as difficulties related to precise power sharing, voltage stability during a contingency, the control and management of power transfer through the interlinking converters (ICs), and the coordination of local distributed energy resources (DERs) with the hosting main grid. An understanding of HMGs and their operational philosophy during islanding will assuredly pave the way toward the realization of a future smart grid that includes a plug-and-play feature and will alleviate any operational challenges. However, the planning and operation of such islanded and hybrid systems are reliant on a powerful and efficient power flow analysis tool. To this end, this thesis introduces a novel unified, generic, flexible power flow algorithm for islanded/isolated HMGs. The developed algorithm is generic in the sense that it includes consideration of the unique characteristics of islanded HMGs: a variety of possible topologies, droop controllability of the DERs and bidirectionality of the power flow in the ICs. The new power flow formulation is flexible and permits the easy incorporation of any changes in the DER operating modes and the IC control schemes. The developed algorithm was validated against a detailed time-domain model and applied for the analysis of a variety of operational and control aspects in islanded HMGs, including the problem of imprecise power sharing and droop control of the ICs. The proposed load flow program can form the basis of and provide direction for further studies of islanded HMGs. This thesis also presents a deeper look at the problem of inaccurate active and reactive power sharing in islanded droop-based HMGs and proposes a unified and universal power sharing scheme that can simultaneously ensure precise power sharing in both ac and dc subgrids. Test results demonstrate the capability of the developed scheme with respect to achieving exact power sharing not only among DERs in proportion to their ratings but also among ICs that interface adjacent ac and dc microgrids. The developed unified power sharing scheme would assist system planners with the effective design of droop characteristics for DERs and ICs, which would result in enhancements such as the avoidance of converter overloading and the achievement of precise load sharing. Another operational aspect that was thoroughly investigated for this thesis is the possibility of voltage instability/collapse in islanded HMGs during contingencies. This research unveiled the possibility of voltage instability in HMGs that include constant power loads and a mix of synchronous-based and converter-based generating units. As indicated by the voltage stability analysis presented here, despite the fact that healthy microgrids have far-reaching loadability boundaries, the voltage at some ac/dc load buses can unexpectedly collapse during abnormal conditions. The analysis also revealed that fine tuning the droop characteristics of DERs and ICs can enlarge the voltage stability margin and safeguard the entire microgrid against collapse during contingencies, all without the sacrifice of a single load. A final component of this thesis is the proposal of a two-stage stochastic centralized dispatch scheme for ac/dc hybrid distribution systems. The developed dispatch scheme coordinates the operation of a variety of DERs, such as distributed generators and energy storage systems. It also ensures the coordinated charging of electric vehicles and models the degradation of their batteries that occurs due to the vehicle-to-grid action. The energy coordination problem has been formulated as a two-stage day-ahead resource scheduling problem: the intermittent supply; the variable demand, which includes electric vehicles; and the fluctuating real-time energy price are all modelled as random variables. The first stage produces day-ahead dispatch decisions for the dispatchable DG units. For a set of possible scenarios over the next 24 h, the second stage determines appropriate corrective decisions with respect to the import/export schedule, storage charging/discharging cycles, and electric vehicle charging/discharging patterns. The simulation results demonstrate the effectiveness of the developed scheme for optimally coordinating the various components of future ac/dc hybrid smart grids. Despite its substantial merits and value as a host for ac and dc technologies, a smart grid with HMGs creates previously unexperienced operational challenges for system planners and operators. The work completed for this thesis could help pave the way for the realization of ac/dc hybrid smart grids in years to come.

Microgrids

Microgrids

Author: Josep M. Guerrero

Publisher: Academic Press

Published: 2021-10-21

Total Pages: 270

ISBN-13: 0323854648

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Microgrids: Modeling, Control, and Applications presents a systematic elaboration of different types of microgrids, with a particular focus on new trends and applications. The book includes sections on AC, DC and hybrid AC/DC microgrids and reflects state-of-the-art developments, covering theory, algorithms, simulations, error and uncertainty analysis, as well as novel applications of new control techniques. Offering a valuable resource for students and researchers working on the integration of renewable energy with existing grid and control of microgrids, this book combines recent advances and ongoing research into a single informative resource. The book highlights recent findings while also analyzing modelling and control, thus making it a solid reference for researchers as well as undergraduate and postgraduate students. Covers different types of microgrids and their architecture and control in a single book Includes original, state-of-the-art research contributions by international experts Features global case studies for better understanding and real-life examples


Book Synopsis Microgrids by : Josep M. Guerrero

Download or read book Microgrids written by Josep M. Guerrero and published by Academic Press. This book was released on 2021-10-21 with total page 270 pages. Available in PDF, EPUB and Kindle. Book excerpt: Microgrids: Modeling, Control, and Applications presents a systematic elaboration of different types of microgrids, with a particular focus on new trends and applications. The book includes sections on AC, DC and hybrid AC/DC microgrids and reflects state-of-the-art developments, covering theory, algorithms, simulations, error and uncertainty analysis, as well as novel applications of new control techniques. Offering a valuable resource for students and researchers working on the integration of renewable energy with existing grid and control of microgrids, this book combines recent advances and ongoing research into a single informative resource. The book highlights recent findings while also analyzing modelling and control, thus making it a solid reference for researchers as well as undergraduate and postgraduate students. Covers different types of microgrids and their architecture and control in a single book Includes original, state-of-the-art research contributions by international experts Features global case studies for better understanding and real-life examples

Operational Control and Analysis of a Hybrid AC/DC Microgrid

Operational Control and Analysis of a Hybrid AC/DC Microgrid

Author: Hasan Alsiraji

Publisher:

Published: 2018

Total Pages: 139

ISBN-13:

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In light of the growing demand for electrical power around the globe, the need to increase electrical power generation in order to diminish total carbon emissions has led to the installation of renewable resources to replace traditional generators. Most of today's microgrids are AC microgrids, whose advantages and shortcomings with respect to control techniques and stability assessment have been demonstrated through extensive studies reported in the literature. These considerations have led to the recent proposal and investigation of DC microgrids, accompanied by the introduction of the hybrid AC/DC microgrid as a means of combining the advantages and benefits of both types of microgrid. However, since a hybrid microgrid is viewed as a weak system with low inertia, controlling and assessing the performance of a hybrid microgrid constitutes a high-priority issue that requires further investigation. The lack of inertia of power electronics converters, especially in an islanded hybrid microgrid, poses a threat to stability and control. For these reasons, effective stability analysis has become a necessity with respect to the implementation of hybrid microgrids. Because of these challenges, the emulation of synchronous machine (SM) inertia and damping is now viewed as necessary for enhancing the effect of a VSC on an active distribution system and for facilitating its participation in voltage and frequency support. Improving the stability and performance of a hybrid microgrid therefore requires the introduction of a form of inertia into a hybrid microgrid. This research first proposes the incorporation of a novel form of virtual inertia into a hybrid microgrid using virtual synchronous machine (VSM) control of the intertying converter (IC) controller. The second proposal of this research is to employ the VSM control to establish autonomous control of the IC. A first research component, a novel control strategy for the Intertying converter in hybrid AC/DC microgrid has been proposed to ensure the benefit of a virtual synchronous machine (VSM) control algorithm in the hybrid AC/DC microgrid. The VSM controller application in hybrid AC/DC microgrid is capable to enable an IC converter to support the AC-side voltage and frequency as well as the DC-side voltage. The proposed control application of the VSM is chosen based on a comprehensive assessment of VSM control algorithms that are exist in the literature. Moreover, proposing an autonomous operation control of the VSM intertying converter based on dual droop characteristics which is quite different compared to using only current controller. The autonomous operation of the intertying converter based on dual droop control is modified and proposed to be capable to feed the VSM controller (swing equation) to ensure accurate power exchange management between the AC and DC sub-subsystems. The most important portion for the hybrid microgrid system is the stability study due to that fact that the behavior of the system when it is subjected to a temporary disturbance is the main concern. In hybrid microgrid, the disturbances take place continuously because of the load changing endlessly. Satisfying the hybrid microgrid operation during the disturbances conditions must be achieved in order to supply the demand. Therefore, the second part of the research introduces a generic small-signal state space model of the hybrid AC/DC microgrid system, and built to carry out the stability analysis. The development of the small-signal state-space model for the entire hybrid AC/DC microgrid was developed to investigate the overall system stability under different operating points. The final part of this thesis reveals three serious issues of operating hybrid AC/DC microgrid; some of these issues are temporary take a place based on the system operating conditions. In hybrid AC/DC microgrid, an Intertying converter (IC) becomes harmonics voltage source due to the antiparallel diodes and the shunt capacitor at its DC side. The nonlinearity behavior of ICs introduces another operation issue that is circulating current in case of parallel ICs. Reconnecting an IC after abnormal operation condition or schedule maintenance requires an extra challenging synchronization control due the variation of the AC subgrid voltages and frequency; which is the third issue. This part proposes a solution for all these issues by developing a new control strategy that combines the VSM control concept with a dual based droop control. The developed VSM controller on the IC solves these issues. The test system used in this research, which is simulated in a PSCAD/EMTDC environment, consisted of simulated voltage source converters with two AC voltage levels; while the stability analysis is conducted in MATLAB environment.


Book Synopsis Operational Control and Analysis of a Hybrid AC/DC Microgrid by : Hasan Alsiraji

Download or read book Operational Control and Analysis of a Hybrid AC/DC Microgrid written by Hasan Alsiraji and published by . This book was released on 2018 with total page 139 pages. Available in PDF, EPUB and Kindle. Book excerpt: In light of the growing demand for electrical power around the globe, the need to increase electrical power generation in order to diminish total carbon emissions has led to the installation of renewable resources to replace traditional generators. Most of today's microgrids are AC microgrids, whose advantages and shortcomings with respect to control techniques and stability assessment have been demonstrated through extensive studies reported in the literature. These considerations have led to the recent proposal and investigation of DC microgrids, accompanied by the introduction of the hybrid AC/DC microgrid as a means of combining the advantages and benefits of both types of microgrid. However, since a hybrid microgrid is viewed as a weak system with low inertia, controlling and assessing the performance of a hybrid microgrid constitutes a high-priority issue that requires further investigation. The lack of inertia of power electronics converters, especially in an islanded hybrid microgrid, poses a threat to stability and control. For these reasons, effective stability analysis has become a necessity with respect to the implementation of hybrid microgrids. Because of these challenges, the emulation of synchronous machine (SM) inertia and damping is now viewed as necessary for enhancing the effect of a VSC on an active distribution system and for facilitating its participation in voltage and frequency support. Improving the stability and performance of a hybrid microgrid therefore requires the introduction of a form of inertia into a hybrid microgrid. This research first proposes the incorporation of a novel form of virtual inertia into a hybrid microgrid using virtual synchronous machine (VSM) control of the intertying converter (IC) controller. The second proposal of this research is to employ the VSM control to establish autonomous control of the IC. A first research component, a novel control strategy for the Intertying converter in hybrid AC/DC microgrid has been proposed to ensure the benefit of a virtual synchronous machine (VSM) control algorithm in the hybrid AC/DC microgrid. The VSM controller application in hybrid AC/DC microgrid is capable to enable an IC converter to support the AC-side voltage and frequency as well as the DC-side voltage. The proposed control application of the VSM is chosen based on a comprehensive assessment of VSM control algorithms that are exist in the literature. Moreover, proposing an autonomous operation control of the VSM intertying converter based on dual droop characteristics which is quite different compared to using only current controller. The autonomous operation of the intertying converter based on dual droop control is modified and proposed to be capable to feed the VSM controller (swing equation) to ensure accurate power exchange management between the AC and DC sub-subsystems. The most important portion for the hybrid microgrid system is the stability study due to that fact that the behavior of the system when it is subjected to a temporary disturbance is the main concern. In hybrid microgrid, the disturbances take place continuously because of the load changing endlessly. Satisfying the hybrid microgrid operation during the disturbances conditions must be achieved in order to supply the demand. Therefore, the second part of the research introduces a generic small-signal state space model of the hybrid AC/DC microgrid system, and built to carry out the stability analysis. The development of the small-signal state-space model for the entire hybrid AC/DC microgrid was developed to investigate the overall system stability under different operating points. The final part of this thesis reveals three serious issues of operating hybrid AC/DC microgrid; some of these issues are temporary take a place based on the system operating conditions. In hybrid AC/DC microgrid, an Intertying converter (IC) becomes harmonics voltage source due to the antiparallel diodes and the shunt capacitor at its DC side. The nonlinearity behavior of ICs introduces another operation issue that is circulating current in case of parallel ICs. Reconnecting an IC after abnormal operation condition or schedule maintenance requires an extra challenging synchronization control due the variation of the AC subgrid voltages and frequency; which is the third issue. This part proposes a solution for all these issues by developing a new control strategy that combines the VSM control concept with a dual based droop control. The developed VSM controller on the IC solves these issues. The test system used in this research, which is simulated in a PSCAD/EMTDC environment, consisted of simulated voltage source converters with two AC voltage levels; while the stability analysis is conducted in MATLAB environment.

Wind and Solar Energy Applications

Wind and Solar Energy Applications

Author: Satish Kumar Peddapelli

Publisher: CRC Press

Published: 2023-03-22

Total Pages: 374

ISBN-13: 1000836428

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This book examines the recent advances, from theoretical and applied perspectives, addressing the major issues associated with renewable energy systems, with each chapter covering fundamental issues and latest developments. This book covers important themes, including solar energy equipment, wind and solar energy systems, energy storage and bioenergy applications, hybrid renewable energy systems, as well as the measurement techniques that are used for these systems. Further, it focusses on original research outcomes on various technological developments and provides insights to taxonomy of challenges, issues, and research directions in renewable energy applications. Features: Covers research and technological developments in wind and solar energy applications Proposes resolution of limitations and performance issues of existing system models and design Incorporates the challenges of adoption of renewable energies system Provides hypotheses, mathematical analysis, and real-time practical applications to practical problems Includes case studies of implementation of solar and wind systems in remote areas This book is aimed at researchers, professionals, and graduate students in electrical and mechanical engineering and renewable energy.


Book Synopsis Wind and Solar Energy Applications by : Satish Kumar Peddapelli

Download or read book Wind and Solar Energy Applications written by Satish Kumar Peddapelli and published by CRC Press. This book was released on 2023-03-22 with total page 374 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book examines the recent advances, from theoretical and applied perspectives, addressing the major issues associated with renewable energy systems, with each chapter covering fundamental issues and latest developments. This book covers important themes, including solar energy equipment, wind and solar energy systems, energy storage and bioenergy applications, hybrid renewable energy systems, as well as the measurement techniques that are used for these systems. Further, it focusses on original research outcomes on various technological developments and provides insights to taxonomy of challenges, issues, and research directions in renewable energy applications. Features: Covers research and technological developments in wind and solar energy applications Proposes resolution of limitations and performance issues of existing system models and design Incorporates the challenges of adoption of renewable energies system Provides hypotheses, mathematical analysis, and real-time practical applications to practical problems Includes case studies of implementation of solar and wind systems in remote areas This book is aimed at researchers, professionals, and graduate students in electrical and mechanical engineering and renewable energy.

DC Microgrids

DC Microgrids

Author: Nikita Gupta

Publisher: John Wiley & Sons

Published: 2022-06-21

Total Pages: 484

ISBN-13: 111977716X

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DC MICROGRIDS Written and edited by a team of well-known and respected experts in the field, this new volume on DC microgrids presents the state-of-the-art developments and challenges in the field of microgrids for sustainability and scalability for engineers, researchers, academicians, industry professionals, consultants, and designers. The electric grid is on the threshold of a paradigm shift. In the past few years, the picture of the grid has changed dramatically due to the introduction of renewable energy sources, advancements in power electronics, digitalization, and other factors. All these megatrends are pointing toward a new electrical system based on Direct Current (DC). DC power systems have inherent advantages of no harmonics, no reactive power, high efficiency, over the conventional AC power systems. Hence, DC power systems have become an emerging and promising alternative in various emerging applications, which include distributed energy sources like wind, solar and Energy Storage System (ESS), distribution networks, smart buildings, remote telecom systems, and transport electrification like electric vehicles (EVs). All these applications are designed at different voltages to meet their specific requirements individually because of the lack of standardization. Thus, the factors influencing the DC voltages and system operation needed to be surveyed and analyzed, which include voltage standards, architecture for existing and emerging applications, topologies and control strategies of power electronic interfaces, fault diagnosis and design of the protection system, optimal economical operation, and system reliability.


Book Synopsis DC Microgrids by : Nikita Gupta

Download or read book DC Microgrids written by Nikita Gupta and published by John Wiley & Sons. This book was released on 2022-06-21 with total page 484 pages. Available in PDF, EPUB and Kindle. Book excerpt: DC MICROGRIDS Written and edited by a team of well-known and respected experts in the field, this new volume on DC microgrids presents the state-of-the-art developments and challenges in the field of microgrids for sustainability and scalability for engineers, researchers, academicians, industry professionals, consultants, and designers. The electric grid is on the threshold of a paradigm shift. In the past few years, the picture of the grid has changed dramatically due to the introduction of renewable energy sources, advancements in power electronics, digitalization, and other factors. All these megatrends are pointing toward a new electrical system based on Direct Current (DC). DC power systems have inherent advantages of no harmonics, no reactive power, high efficiency, over the conventional AC power systems. Hence, DC power systems have become an emerging and promising alternative in various emerging applications, which include distributed energy sources like wind, solar and Energy Storage System (ESS), distribution networks, smart buildings, remote telecom systems, and transport electrification like electric vehicles (EVs). All these applications are designed at different voltages to meet their specific requirements individually because of the lack of standardization. Thus, the factors influencing the DC voltages and system operation needed to be surveyed and analyzed, which include voltage standards, architecture for existing and emerging applications, topologies and control strategies of power electronic interfaces, fault diagnosis and design of the protection system, optimal economical operation, and system reliability.