Operation Of Microgrid Research Articles

Improved islanded microgrid performance with sliding mode controller based electric spring

In this research manuscript, an innovative solution is proposed to address intermittency challenges in self-excited induction generator-based islanded microgrids. The approach makes the use of an electric spring to maintain a constant voltage across critical loads. For simplifying the design and reduce the need for additional storage devices, and lower costs, a novel voltage source-based electric spring concept is introduced, complete with a comprehensive modelling approach specifically tailored for microgrid applications. Furthermore, a first-order sliding mode controller is suggested to enhance voltage and frequency regulation, stability, and overall system efficiency. This control strategy is designed to linearize voltage errors and provide swift responses under varying steady-state and transient conditions. To validate the effectiveness of the proposed scheme, the model is compared against the widely used quadrature voltage injection scheme under different load and torque conditions. Moreover, the system exhibits a rapid settling time, typically requiring only one to two cycles to stabilize. This underscores the robustness and stability of the controller. The validation of this work is carried out in real-time using an OPAL-RT 4510 and MATLAB/Simulink platform.

Novel design and adaptive coordinated energy management of hybrid fuel‐cells/tidal/wind/PV array energy systems with battery storage for microgrids

AbstractThis paper proposes a comprehensive solution to the challenges of managing a hybrid microgrid that generates electricity from multiple sustainable energy sources by proposing a coordinated energy management strategy and storage system. As renewable energy generation becomes increasingly popular, it introduces greater intermittency and stochasticity in energy management. To address this issue, a coordinated energy management strategy and storage system is proposed, which includes a fuzzy logic modified super twisting algorithm (MSTA). The objectives are to optimize the design and operation of microgrid including electrical based energy conversion systems such as photovoltaic and wind turbines, fuel cells, tidal energy, electric vehicle charging stations, and main grid. The second objective is to develop an energy management system for hybrid energy storage systems (HESS) and renewable energy sources (RESs) to maximize power production and ensure service continuity and smooth output energy of the microgrid, while also providing optimal benefits. To maintain cost‐effectiveness, an On/Off maximum power point tracking (MPPT) algorithm is also proposed. The contribution of this paper is to provide a solution to the intermittent and stochastic nature of renewable energy management and to improve the efficiency and durability of the energy conversion systems. The proposed management unit provides consistent output power and long‐term service.

Impacts of multiple demand-side management strategies on microgrids planning: a literature survey

Abstract Demand-side management (DSM) schemes play a crucial role in managing renewable energy generation and load fluctuations by utilizing demand–response programmes (DRPs). This paper aims to provide a detailed overview of DRPs that help microgrid operators to keep costs and reliability within acceptable ranges. Additionally, this review paper provides a detailed economic load model for DRPs based on initial load, demand–response (DR) incentive, DR penalty and elasticity coefficients. This article also aims to guide researchers in identifying research gaps in DSM applications in microgrids by comparing various DSM schemes from different countries and regions in terms of DSM strategies, objective functions and optimization techniques. Furthermore, this study analyses the impact of DRPs on microgrid configuration from the perspective of utilities and customers, considering technical and economic performance metrics. As a result, it can be concluded that none of the studied cases provides models or guidelines for choosing appropriate DSM schemes that consider different consumer interests or load-type features. Furthermore, a few researchers have addressed the features of a modern price-based DR strategy, renewable generation-based dynamic pricing DR, which offers higher customer satisfaction than traditional DRPs.

Cloud Assisted IoT-Operated Small Residential Microgrid with Collusive Model Approach for Energy Trading

This article explores a strategic approach for an energy-self-sufficient and economically sustainable small residential community, powered by rooftop solar photovoltaics. This community plays the role of a microgrid (MG) with a microgrid operator (MO). It operates in two distinct modes: within the MG (peer-to-peer or P2P) and with the utility grid. The P2P transfer is experimentally performed with open-source Internet of Things (IoT) applications from the cloud. This will enable a low-cost MG operation for developing countries. Residents from the community are elected considering their support towards community welfare, and they are considered as delegates. The MO with delegates, control the energy transfer operation. This approach distributes generated energy among community members at low prices if there is energy demand, minimizing carbon footprint. The action of selling energy by a prosumer during the need of fellow resident is considered as the token of social service towards the community. A social service counter (SSC) is chosen to identify services for each prosumer in the MG. When a seller sells energy within the community, the SSC increases. This count rewards the prosumer in several ways. MO only allows prosumers to participate in energy trading with the grid during the high-demand hours of the day. Delegates play an essential role in protecting the community's interest while selling energy outside the community. They try to form a coalition among participants to reduce installation costs and maximize the cumulative payoff. A comparative study between the proposed coordination game and two competitive game approaches, namely Cournot and Stackelberg's algorithm in the restricted domain, reveals that the proposed method is well suited for a small residential MG. Shapley value is a tool that identifies each delegate's contribution during the game. The paper employed this method for the overall coordination game to identify the most acceptable payoff for individual players.

Low carbon dispatch of the park integrated energy system based on the electric vehicles flexible load storage characteristics

The integrated energy system is an efficient way of utilizing energy in industry park. However, with the massive integration of renewable energy and disorganized charging of electric vehicles, the safe operation of this system faces several challenges. To address these issues, we propose a novel dispatch model that incorporates the flexible load characteristics of electric vehicles clusters. Firstly, we elucidate the operational framework for the integrated energy system in parks and establish models for users and microgrid operators incorporating carbon trading mechanisms. These models can effectively portray how an integrated energy system operates within a park setting. Secondly, using charging data from parks, we uncover potential dispatchable charging/discharging capacities for electric vehicles clusters and formulate strategies to utilize electric vehicles as flexible loads in our dispatch operation policy. By appropriately regulating electric vehicles charging/discharging behaviors, demand-supply balance within the system can be better achieved. Subsequently, aiming to maximize benefits for all entities in the park area, we construct a master-slave game model that involves multiple users and microgrid operators. Lastly, employing reinforcement learning concepts, we establish an equivalent power output models for wind turbines, photovoltaic power generation and apply it to an integrated energy system in an industrial park in a specific city. An analysis reveals that our proposed model not only minimizes cost associated with energy storage equipment but also significantly reduces carbon emissions; yielding mutual benefits for both microgrid operators and users.

Fortifying the grid in the Southeastern U.S. through microgrids: Navigating an uncertain regulatory environment

AbstractOne shortcoming of the current grid in North America is a lack of resiliency and reliability in inclement weather and the general need for investment to update its aging infrastructure. This is especially apparent in the Southeastern U.S., where tornadoes, hurricanes, flooding, and lightning strikes regularly disrupt power to customers. One way to increase grid resiliency in natural disasters is through the implementation of microgrids, which are a group of customers within defined electrical boundaries with the ability to connect to the grid or disconnect from the grid and operate independently in island mode. There are several factors impeding microgrid adoption, especially regulatory uncertainty. In many states, and particularly Southeastern states, there are not explicit tariffs regulating the interconnection and operation of microgrids, making investment in microgrids risky. Microgrids have been difficult for states to regulate because they often integrate multiple energy technologies and have complex ownership structures. There are three primary policy suggestions that could enhance microgrid adoption in the Southeastern U.S.: (1) States should adopt regulatory frameworks for microgrids that properly value the resiliency and grid benefits of microgrids, particularly through legislation that establishes legal definitions and rights of microgrids. (2) State legislatures should consider a shift to performance‐based ratemaking (PBR) rather than cost‐of‐service (COS) ratemaking to better prioritize certain performance goals, such as grid resiliency, and encourage more widespread adoption of microgrids. (3). To improve the economics of microgrids, state legislatures should consider authorizing community choice aggregation (CCA).

Simulation study on capacity planning and allocation of island microgrid

In this paper, the energy storage capacity planning problem of a real island microgrid is deeply simulated. In the beginning, the overview and basic data of the island microgrid are described in detail, including the composition of the grid and its key parameters. Then, with the help of modeling and simulation technology, the operation of microgrid in various scenarios is comprehensively simulated and analyzed, focusing on how to optimize energy storage planning in the case of wind energy removal to ensure the smooth operation of the grid. The research deeply reveals the core role of stable power system in ensuring the reliability of power supply and the normal operation of the system. Among them, frequency stability is regarded as the cornerstone of power system operation, which is indispensable for maintaining the overall stability of the power grid and ensuring the continuous and stable power supply of users.Through this simulation study, we not only provide feasible schemes and suggestions for the energy storage capacity planning and allocation of island microgrids, but also verify that reasonable energy storage schemes have a positive effect on the overall stability and reliability of the power system.

Coordination of protection and operation in micro-grids with inverter based distributed generation using SAOA.

In the proposed protection coordination scheme, the depreciation of the operation time of the entire relay in the primary and backup protection modes for all possible fault locations is considered as the objective function. The limitations of this problem include the equations for calculating the operation time of the relays in both forward and reverse directions, the limitation of the coordination time interval, the limitation of the setting parameters of the proposed relays, the restriction of the size of the reactance that limits the fault current, and the limitation of the standing time of distributed generation per small signal fault. The operation time of the relays depends on the short circuit current passing through them, so it is necessary to calculate the network variables before the fault occurs. For this purpose, optimal daily power distribution should be used in the micro-grid, because micro-grids consist of storage and renewable resources. The proposed plan includes the uncertainties of consumption and generation capacity of renewable resources. Then, to achieve a reliable answer with a low standard deviation, the refrigeration optimization algorithm is used to solve the proposed problem. Finally, the proposed design is implemented on the standard test system in the MATLAB software, and then the capabilities of the proposed design are examined.

Integrating Demand Response with Unit Commitment in Insular Microgrid considering Forecasting Errors and Battery Storage

In this paper, DR programs are integrated with the unit commitment economic dispatch model for a single day to lower total operating costs for an insular microgrid. The proposed model takes into account the forecasting errors associated with wind, solar, and load demands. A new combined DR program is presented to enhance microgrid operation and financial effectiveness, benefiting microgrid consumers. The price elasticity and consumer profit are the foundation for DR modeling. The optimization problem is developed as mixed‐integer nonlinear programming (MINLP) and solved using GAMS software. For the case study, an insular microgrid consisting of two microturbines, a wind turbine, solar photovoltaic, and battery storage is considered. Optimization is carried out under both with and without the DR program. The outcomes show that by implementing TOU and DLC DR programs, the operating cost is reduced by 13.55% and 9.68%, respectively. While consumers experience a financial loss in TOU‐DR, they earn profit in DLC‐DR. Therefore, a combination of the two, i.e., TOU + DLC DR, is proposed, reducing operating costs by 10.73% while increasing profit for users. The suggested approach benefits the microgrid operator as well as its users, encouraging the construction and operation of insular microgrids in rural or isolated areas.

An overview of the current Advanced Techniques for Frequency Regulation in grid-connected and off-grid Microgrids.

The integration of renewable energy sources into the power system is an important step towards a sustainable energy transition. This transition could subsequently introduce substantial variability that critically impacts key operational parameters, such as frequency and voltage. This variability poses significant challenges, especially within microgrid configuration, both in grid-connected and isolated modes. Therefore, ensuring the stability of these parameters I paramount of their operational efficiency, reliability, and longevity. Despite these challenges, recent advancements in the field have led to the development of numerous advanced methodologies and control strategies designed to mitigate the impact of renewable sources on microgrid frequency stability. This paper provides a comprehensive overview of these state-of-the-art technologies and methodologies, including cutting-edge technologies such as adaptive load frequency control and Time-series prediction-based approaches. It offers insights into their application, effectiveness, and advantages in frequency control during microgrid operation, contributing to the ongoing discourse on integrating renewable energy sources with enhanced grid stability. Moreover, the discussion section provides insights and barriers impacting the implementation of these technologies in the current microgrid system and the power grid in general.

A Coordinated Optimal Operation of a Grid-Connected Wind-Solar Microgrid Incorporating Hybrid Energy Storage Management Systems

The hybrid-energy storage systems (ESSs) are promising eco-friendly power converter devices used in a wide range of applications. However, their insufficient lifespan is one of the key issues by hindering their large-scale commercial application. In order to extend the lifespan of the hybrid-ESSs, the cost functions proposed in this paper include the degradation of the hydrogen devices and the battery. Indeed, this paper aims to develop a sophisticated model predictive control strategy for a grid-connected wind and solar microgrid, which includes a hydrogen-ESS, a battery-ESS, and the interaction with external consumers, e.g., battery/fuel cell electric vehicles. The integrated system requires the management of its energy production in different forms, i.e., the electric and the hydrogen ones. The proposed strategy consists of the economical and operating costs of the hybrid-ESSs, the degradation issues, and the physical and dynamic constraints of the system. The mixed-logic dynamic framework is required to model the operating modes of the hybrid-ESSs and the switches between them. The effectiveness of the controller is analyzed by numerical simulations which are conducted using solar and wind generation profiles of solar panels and wind farms located in Abu Dhabi, United Arab Emirates. Such simulations, indeed, show that the proposed strategy appropriately manages the plant by fulfilling constraints and energy requests while reducing device costs and increasing battery life.

Smooth and Uninterrupted Operation of Standalone DC Microgrid Under High and Low Penetration of RESs

Smooth and Uninterrupted Operation of Standalone DC Microgrid Under High and Low Penetration of RESs

Adaptive Load Shedding as Part of Primary Frequency Response To Support Networked Microgrid Operations

Global changes in the deployment of distributed energy resources, control and communications technologies, business models, and regulatory policy are increasing the operational options for future distribution systems. One such option is the coordinated operation of distributed resources to form microgrids and networks of microgrids to support traditional bulk power systems during normal operations and critical end-use loads during outages. While individual standalone microgrids have been extensively studied and deployed, the coordinated operation of networked microgrids is operationally more challenging due to the dynamic boundaries and changing mix of generation resources. This paper presents a method of using a distributed control architecture to support primary frequency response in networked microgrids operations. The support of primary frequency response is accomplished using the Open Field Message Bus reference architecture and Grid Friendly Appliance controllers.

Coordinated Operation of Multiple Microgrids With Heat–Electricity Energy Based on Graph Surrogate Model-Enabled Robust Multiagent Deep Reinforcement Learning

Coordinated Operation of Multiple Microgrids With Heat–Electricity Energy Based on Graph Surrogate Model-Enabled Robust Multiagent Deep Reinforcement Learning

Two-Stage Coordinated Operation of A Green Multi-Energy Ship Microgrid With Underwater Radiated Noise by Distributed Stochastic Approach

Two-Stage Coordinated Operation of A Green Multi-Energy Ship Microgrid With Underwater Radiated Noise by Distributed Stochastic Approach

Two-Stage Data-Driven Optimal Energy Management and Dynamic Real-Time Operation in Networked Microgrid Based Deep Reinforcement Learning Approach

Two-Stage Data-Driven Optimal Energy Management and Dynamic Real-Time Operation in Networked Microgrid Based Deep Reinforcement Learning Approach

An efficient high-gain bidirectional interleaved boost converter for PV integration to DC microgrid.

The design of a power electronic interface for high voltage difference DC buses is a key aspect in DC microgrid applications. A multi-port non isolated interleaved high-voltage gain bidirectional converter, which facilitates bidirectional power transfer and islanded operation in a DC microgrid, is presented in this paper. The forward high-voltage transfer ratio is achieved using a voltage multiplier circuit, and the high-gain step-down power conversion is performed using a resonant power module. A novel power transfer selection algorithm is proposed to control power flow among the interfaces of the RES, ESS, and DC grid converters, which utilizes the net power difference as the basis for switching the converter. The proposed converter is simulated for a 24 V PV source, 12 V battery, and 400 V DC grid interface using MATLAB/SIMULINK. A 200 W hardware prototype is implemented. The simulation results for voltages, currents, and power flow among RES, ESS, and microgrid DC bus proved an excellent voltage regulation, efficient power conversion, and a feasible duty cycle range with high voltage gain. These observations are validated through equivalent experimental results. A comparison is made regarding achieved gain, component sizing, achievable power transfer modes, efficiency, and control complexity with existing converters for DC microgrid applications. The presented topology proved to be a better interface with multiple-mode support with high efficiency.

Coordinated Control for Islanded DC Microgrid Based on Derivative of Bus Voltage

The unbalanced power generated by unintentional islanding is a tremendous challenge to the stable operation of the DC microgrid. When dealing with this challenge, the existing communication-free voltage-threshold-based coordinated control lags far behind the actual power variation, which exacerbates the risk of voltage violations in the microgrid. To address the drawback of the existing control, this paper proposes a new method based on the derivative of bus voltage. Firstly, based on the mathematical correlation between unbalanced power and the derivative of bus voltage, a coordination control strategy and its switching criterion before the battery energy storage system (BESS) exits operation is proposed. Meanwhile, we propose a communication-free approach to sense the operation state of the BESS based on the dynamic process of the derivative of bus voltage. Thus the information obtained under complicated circumstances could be further enriched. Subsequently, a new control strategy after BESS operates operation is established to coordinate different sources among the microgrid. Compared with the existing coordinated control methods, the proposed one can better utilize the information contained in the dynamic process of the bus voltage. Numerical results validate the effectiveness and advantages of the proposed method.

Robust control of frequency considering operations of AC microgrid in islanded mode

Robust control of frequency considering operations of AC microgrid in islanded mode

Enhancing Stability and Performance of DC Microgrid: A Coordinated Impedance Reshaping Controller Design Approach

Enhancing Stability and Performance of DC Microgrid: A Coordinated Impedance Reshaping Controller Design Approach