Beyond optimization, the real-world application use of networked microgrids involves the integration of a complex communication network, power electronics, protection devices, and various grid components. ORNL’s Networked Microgrids Testbed demonstrates how microgrids interact and operate in different modes. Credit: Carlos Jones, ORNL/U.S. Dept. of Energy
Distributed optimization for networked microgrids
One of the challenges of networked microgrids is how to achieve optimal operation with large numbers of microgrids. To tackle this challenge, ORNL researchers applied a distributed optimization for networked microgrids, which is scalable, preserves data privacy, and can minimize system operating costs while achieving other network objectives.
The following ORNL publications on this subject cover formulation and validation with hardware in the loop:
Networked microgrids with hardware-in-the-loop validation presents distributed energy management for networked microgrids and validates it using hardware in the loop. Read the paper here or at OSTI.gov.
Networked microgrids for improved resilient operation presents a case study on the implementation and benefits of networked microgrids in Adjuntas, Puerto Rico. This study emphasizes the enhanced resilience and operational efficiency achieved through networking microgrids. Read the paper here or at OSTI.gov.
ADMM algorithm discusses a method for managing energy distribution in networked microgrids using the ADMM algorithm, focusing on enhancing the flexibility and reliability of modern electrical distribution systems. This approach allows for dynamic adjustment based on local generation and storage capacities. Read the paper here or at OSTI.gov.
ADMM linear programming introduces a mixed-integer linear programming-based approach to distributed energy management for networked microgrids, considering operational objectives and constraints to optimize performance. Read the paper here or at OSTI.gov.
Energy management for the coordination of networked microgrids presents a distributed energy management system for coordinating networked microgrids, aimed at improving the coordination and efficiency of these systems. Read the paper here or at OSTI.gov.
Robust microgrid scheduling considering unintentional islanding conditions explores robust microgrid scheduling strategies that consider unintentional islanding conditions, focusing on ensuring resilience and efficiency in the scheduling process. Read the paper here or at OSTI.gov.
Robust scheduling of networked microgrids for economics and resilience improvement proposes robust scheduling methods for networked microgrids that enhance both economic performance and resilience, using a distributed approach to manage energy resources effectively. Read the paper here or at OSTI.gov.
Flexible dynamic boundary microgrid operation considering network and load unbalances discusses an approach to operating microgrids with flexible dynamic boundaries, considering network and load imbalances. Read the paper here or at OSTI.gov.
Overview on transactive energy explores the concept of transactive energy and its benefits and challenges for weak power grids. The study highlights how transactive energy systems can enhance grid management and stability but also discusses the technical and regulatory hurdles that need addressing in less robust grid environments. Read the paper here or at OSTI.gov.
Review of distributed secondary control architectures provides a comprehensive review of distributed secondary control architectures in islanded-inverter-based microgrids. The analysis covers various control strategies and their implications for the stability and efficiency of microgrids, particularly emphasizing the need for adaptive and robust control mechanisms. Read the paper here or at OSTI.gov.
Power flow modeling of grid-forming inverters discusses the development and implementation of power flow models for grid-forming inverters in unbalanced distribution grids. The paper focuses on the methodologies used to integrate these inverters effectively, enhancing grid stability and performance. Read the paper here or at OSTI.gov.
Optimal network reconfiguration and scheduling with hardware-in-the-loop validation for improved microgrid resilience proposes an optimization strategy combining network topology reconfiguration and optimal scheduling of distributed energy resources to enhance power system resilience. This was validated through a real-world, three-microgrid case study in Adjuntas, Puerto Rico, in addition to hardware-in-the-loop testing and simulations on the IEEE-33 bus system. Read the paper here.
ORNL developed a hardware-based network microgrid testbed to evaluate advanced controllers. The testbed comprises multiple microgrids designed to operate independently, grid-tied, or as a network of microgrids. Credit: Carlos Jones, ORNL/U.S. Dept. of Energy
Microgrid protection
Microgrids’ resilience can be compromised if they lack proper protection against electrical faults within their electrical boundaries. To address this issue, ORNL and the University of Central Florida collaborated to explore methods that incorporate nontraditional protection elements better suited for microgrids operating in islanded mode. ORNL has further proposed inverter modifications so energy storage inverters can be capable of generating a higher current contribution compatible with conventional distribution protection.
Learn more:
- Grid-forming inverter with increased short-circuit contribution proposes a solution to one of the microgrid’s most significant challenges: the low short-circuit current levels in islanded mode. Hardware and control modifications can increase the short-circuit current to leverage conventional protective devices. Read the paper here or at OSTI.gov.
- Admittance-based protection scheme for microgrid presents a new protection scheme for microgrids based on admittance measurements. It offers insights into how admittance-based methods can enhance the reliability and fault response of microgrid systems. Read the paper here or at OSTI.gov.
- Sequence components for microgrid protection reviews the use of superimposed sequence components in microgrid protection systems. It discusses the effectiveness of these components in identifying and isolating faults within microgrids, thereby improving operational stability. Read the paper here.
- Performance evaluation of a novel sequence-based directional detection strategy for protection of active distribution networks presents a novel directional detection method using superimposed symmetrical sequence quantities to address challenges posed by inverter-based resources in modern distribution networks, validated through a hardware-in-the-loop platform. Read the paper here.
Researcher Max Ferrari adjusts a synchronous machine that emulates wind and diesel generation in a microgrid at ORNL’s Grid Research Integration and Deployment Center, or GRID-C. Credit: Carlos Jones, ORNL/U.S. Dept. of Energy
Machine Learning–Based Load and Generation Forecasting
Forecasting is a critical component for optimizing scheduling of local energy sources and loads. This project proposes a three-layer, machine learning-based forecasting approach that considers three scenarios: full communication, communication with local stations, and no communication link. When full communication is available, data can be obtained from a satellite forecast through an application programming interface. If communication to the satellite forecast service is disrupted because of storm damage, a machine learning forecaster uses historical data and refines the forecast using local measurements from nearby stations. If all communication is lost, the forecaster relies solely on historical data to make its predictions.
Learn More:
- Privacy-aware federated learning framework introduces a federated learning framework designed for privacy-conscious analytics of distributed energy resources in constrained environments. Read the paper here or at OSTI.gov.
- Evaluating recursive blind forecast examines the accuracy of recursive blind forecasting methods against satellite data and baseline forecasts for solar irradiance in Puerto Rico, including during extreme weather conditions. Read the paper here or at OSTI.gov.
- Recursive blind forecasting of photovoltaic generation and consumer load explores advanced forecasting techniques for both photovoltaic generation and consumer load within microgrids. Read the paper here or at OSTI.gov.
- Data quality-aware framework to forecast photovoltaic generation focuses on improving the resilience of microgrids through a data quality-aware forecasting framework. Read the paper here or at OSTI.gov.