Formation of Islanded Droop-Based Microgrids With Optimum Loadability

El-Sayed, Wael T.; Farag, Hany E. Z.; Zeineldin, H. H.; El-Saadany, Ehab F.

doi:10.1109/tpwrs.2021.3099691

Cited by 13 publications

(7 citation statements)

References 32 publications

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“…1. Linearization of Cross-Product Terms within (13)- (14). To linearize AC Power Flow while updating all the voltages, the following formula is used:…”

Section: Practical Considerations Of the Methodsmentioning

confidence: 99%

“…While in a grid-connected mode, micro-grids operate to control current and may inject power into the main grid, in an islanding mode, whereby microgrid is disconnected from the main grid while continuing the supply of power to local customers, micro-grid need to operate in a voltage-control mode to ensure the constant voltage to local loads. In an islanding mode, micro-grids may experience voltage fluctuations, and to recover the nominal voltage (as well as frequency), droop controls are used [12][13][14][15].…”

Section: Droop Controlmentioning

confidence: 99%

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Efficient Operations of Micro-Grids with Meshed Topology and Under Uncertainty through Exact Satisfaction of AC-PF, Droop Control and Tap-Changer Constraints

Bragin¹,

Yan²,

Kumar³

et al. 2022

Preprint

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Micro-grids’ operations offer local reliability; in the event of faults or low voltage/frequency events on the utility side, micro-grids can disconnect from the main grid and operate autonomously while providing the continued supply of power to local customers. With the ever-increasing penetration of renewable generation, however, the operations of micro-grids become increasingly complicated because of the associated fluctuations of voltages. As a result, transformer taps are adjusted frequently, thereby leading to the fast degradation of expensive tap-changer transformers. In the islanding mode, the difficulties also come from the drop of voltage and frequency upon disconnecting from the main grid. To appropriately model the above, the nonlinear AC power flow constraints are necessary. Computationally, the discrete nature of tap-changer operations and the stochasticity caused by renewables add two layers of difficulty on top of a complicated AC-OPF problem. To resolve the above computational difficulties, the main principles of the recently-developed "l1-proximal" Surrogate Lagrangian Relaxation are extended. Testing results based on 9-bus system demonstrate the efficiency of the method to obtain the exact feasible solutions for micro-grid operations thereby avoiding approximations inherent to existing methods, while demonstrating that through the optimization, 1. the number of tap changes is drastically reduced, and 2. the method is capable of handling networks with meshed topologies.

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“…1. Linearization of Cross-Product Terms within (13)- (14). To linearize AC Power Flow while updating all the voltages, the following formula is used:…”

Section: Practical Considerations Of the Methodsmentioning

confidence: 99%

Section: Droop Controlmentioning

confidence: 99%

Efficient Operations of Micro-Grids with Meshed Topology and Under Uncertainty through Exact Satisfaction of AC-PF, Droop Control and Tap-Changer Constraints

Bragin¹,

Yan²,

Kumar³

et al. 2022

Preprint

View full text Add to dashboard Cite

show abstract

“…The most challenging aspect of the distribution network's partitioning is to form an optimal microgrid while maintain operational constraints, such as power balance and voltage limits at each node [44], [45]. Existing microgrid formation strategies can be broadly categorized into four techniques as shown in Fig.…”

Section: Microgrid Construction Modelsmentioning

confidence: 99%

Service Restoration Through Microgrid Formation in Distribution Networks: A Review

Igder

Mitolo

2022

IEEE Access

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Microgrid formation is a promising solution to enhance resiliency of distribution networks. The self-adequacy feature of a microgrid enables continuity of power supply through distributed generation (DG) units during severe faults and natural disasters. In this paper, different methods commonly used to partition a distribution network into multiple microgrids are presented, including the graph theory, heuristic rulebased algorithm, cluster-based technique, and mixed integer programming. Advantages and disadvantages of these techniques and future research directions are presented. This review provides an excellent summary on service restoration through micrgrid formation, and offers a valuable reference for researchers working on grid modernization of distribution networks.

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“…In other words, setting and tuning the droop control gains should guarantee the stability of the system. In the research papers about the droop controlled-based energy management of microgrids, only optimal operation and economic aspect of droop-controlled MGs have been considered without discussing the stability concerns of MGs [5], [6], [19]. Other studies on microgrids have focused on small signal stability without considering the operational optimization of MGs.…”

Section: Introductionmentioning

confidence: 99%

Computationally Distributed and Asynchronous Operational Optimization of Droop-Controlled Networked Microgrids

Nikmehr

Bragin

Zhang

et al. 2022

IEEE Open J. Power Energy

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Networked microgrids (MGs) with inverter-based and droopcontrolled distributed energy resources (DERs) require operational optimization with guaranteed stability performance to ensure the stable energy supply with minimum cost, yet it remains an open challenge. Additionally, the discrete nature of MGs leads to convergence issues to existing optimization methods thereby leading to difficulties obtaining feasible solutions for large-scale networks. This article develops a paradigm for discrete droop control to improve microgrids' controllability in managing voltage and frequency fluctuations. With the emergence of Internet of Things, the computational tasks are distributed among local resources. The utilized Distributed and Asynchronous Surrogate Lagrangian Relaxation (DA-SLR) method distributes the optimization tasks among the MGs and efficiently coordinates the distributed subsystems. A small-signal model of the operational optimization is then developed to verify the system's stability. Numerous case studies have proven the DA-SLR's efficacy in comparison to various variations of the alternating direction of multipliers method (ADMM).

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Formation of Islanded Droop-Based Microgrids With Optimum Loadability

Cited by 13 publications

References 32 publications

Efficient Operations of Micro-Grids with Meshed Topology and Under Uncertainty through Exact Satisfaction of AC-PF, Droop Control and Tap-Changer Constraints

Efficient Operations of Micro-Grids with Meshed Topology and Under Uncertainty through Exact Satisfaction of AC-PF, Droop Control and Tap-Changer Constraints

Service Restoration Through Microgrid Formation in Distribution Networks: A Review

Computationally Distributed and Asynchronous Operational Optimization of Droop-Controlled Networked Microgrids

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