Control of Microgrid – A Review on Recent Trends (original) (raw)

Control of Microgrids: Aspects and Prospects

A microgrid is a controllable component of the smart grid defined as a part of distribution network capable of supplying its own local load even in the case of disconnection from the upstream network. Microgrids incorporate large amount of renewable and non-renewable distributed generation (DG) that are connected to the system either directly or by power electronics (PE) interface. The diversity of technologies used in DGs and loads, high penetration of DGs, economic operation of DGs, dynamics of low-inertia conventional DGs and PE interfaced inertialess DGs and smart operation by means of enhanced communication infrastructure have raised challenges in widespread utilization of microgrids as basis of smart grids. Power quality, protection, economic and secure operation, active management, communication, dynamics and control of microgrids are among the most important issues under research both in academy and industry. Technical concerns over dynamics of microgrids especially in autonomous (island) mode necessitate revision of current paradigms in control of energy systems. This paper addresses current challenges towards controlling microgrids and surveys dynamic modeling, stability and control of microgrids. Future trends in realizing smart grids through aggregation of microgrids and research needs in this path are discussed at the end of this paper.

An Overview on Microgrid Control Strategies

—In response to the ever increasing energy demand, integrating distributed energy resource-based microgrid will be the most promising power system improvement in the near future. Microgrid system implementation provides significant advantages for both electric utility provider and end customer user. This paper performs a comprehensive literature review on the current key issues on control strategies of microgrid islanded mode operation. Brief descriptions are provided for typical microgrid control methods, PQ control, droop control, voltage/frequency control, and current control, which are associated with microgrid mode of operation. This review also covers microgrid control issues such as islanded mode, stability, and unbalanced voltages to provide adequate power quality. In addition, this paper discusses the challenges of microgrid islanded mode issues, such as load sharing, distributed generation losses, and non-linear /unbalanced load. Finally, research conclusions of the important microgrid control requirements for future development are also described.

Microgrid: Future Key to Intelligent Power Network

International journal of engineering research and technology, 2018

Microgrids are small scale version of the power grid in which distributed energy resources, storage devices and loads are localized in a defined geographical area. A microgrid offers an alternate solution to the grid stress problem. Microgrids are building blocks of the Smart Electrical Grid. Microgrids can be operated in grid tied and islanded mode. Power quality is a very important issue in a microgrid because it directly affects the operation of a microgrid. In this paper operational behavior of microgrid under various modes and loading conditions has been studied. Various issues and challenges are presented. Multi loop Control structure has been employed for the controller design to improve the performance of the microgrid. The purpose of this research work is to understand the dynamics of microgrid in grid tied and islanded mode to ensure reliable and secure operation. Simulation results for various conditions are performed to evaluate the performance of microgrid. It is shown ...

Microgrid, Its Control and Stability: The State of The Art

2021

Some of the challenges facing the power industries globally include power quality and stability, diminishing fossil fuel, climate change amongst others. The use of distributed generators however is growing at a steady pace to address these challenges. When interconnected and integrated with storage devices and controllable load, these generators operate together in a grid, which has its own incidental stability and control issues. The focus of this paper, therefore, is on the review and discussion of the different control approaches and the hierarchical control on microgrid, the current practice in literature with respect to stability and the control techniques deployed for microgrid control; the weakness and strength of the different control strategies was discussed in this work and some of the areas that require further research are highlighted.

IJERT-Overview of the Microgrid Concept and its Hierarchical Control Architecture

International Journal of Engineering Research and Technology (IJERT), 2016

https://www.ijert.org/overview-of-the-microgrid-concept-and-its-hierarchical-control-architecture https://www.ijert.org/research/overview-of-the-microgrid-concept-and-its-hierarchical-control-architecture-IJERTV5IS030080.pdf The advent of the Smart Grid has enticed a lot of interest in the research of Distributed Generation (DG) thereby bringing into existence an intelligent electrical power distribution network. This distribution network is designed to possess desired characteristics such as reliability, security, stability and sustainability of energy. Distributed Generation (DG) employs various dispersed energy sources to generate electric power reliably and close to the load that is being served. The energy sources in DGs may include both renewable and non-renewable sources. The Microgrid (MG) concept is an integral part of the DG system and has been proven to possess the promising potential of providing clean, reliable and efficient power by effectively integrating renewable energy sources as well as other distributed energy sources. The energy sources include solar photovoltaics (PV), wind, fuel cell, micro-turbine, biomass, micro-hydro etc. Various architectures of MG are available and many more are still being developed. The architecture of an MG depends on a number of factors such as availability of renewable resources, geographical location of site, load demand etc. For effective and efficient operation, unlike the main grid, the Microgrid (MG) needs to employ special and proper control strategies. This is so because of the combination of conventional or traditional distributed energy sources and the high penetration of renewable energy sources most of which are intermittent in nature. As such, there is need for a control system that ensures proper sharing of the load among the distributed energy sources and also proper power flow between the microgrid and the main grid. The control system should be able to regulate the voltage as well as the frequency, both during islanded operations of the microgrid and grid-tied operation. This paper gives an outline of a microgrid, its general architecture and also gives an overview of the three-level hierarchical control system of a microgrid. The paper further highlights the importance of the Hierarchical control in the effective operation of the microgrid.

A Comprehensive Study on Microgrid Technology

International Journal of Renewable Energy Research, 2014

Grid connection capability of distributed generation attracts researchers due to the cumulative demand for electricity and environment pollution concern as a new emerging technology for providing reliable and clean power supply. A microgrid comprises distributed generation, energy storage, loads, and a control system that is capable of operating in grid-tied mode and/or islanded mode. As operation modes are shifted, the microgrid should successfully manage the voltage and frequency adjustment in order to protect the grid and any loads connected to the system. Facilitation of the generation-side and load-side management and the resynchronization process is required. This paper presents an overall description and typical distributed generation technology of a microgrid. It also adds a comprehensive study on energy storage devices, microgrid loads, interfaced distributed energy resources (DER), power electronic interface modules and the interconnection of multiple microgrids. Details o...

A Review of Control Strategies for Microgrids

Global demand for electrical energy has never been higher than it is currently. This high demand for electricity has driven need for innovative and sustainable power production schemes. The current power system is therefore challenged with the need for quality, reliable and sustainable power production. In most countries, the system is aging, making it require more resources to meet contemporary challenges, coupled with the requirements to maintain a clean environment and mitigate environmental disasters. These lead to the microgrid concept. Deployment and use of the microgrid comes with new challenges-control and protection. In this paper, some of the most obvious control challenges of microgrid operations have been articulated. Nine (9) of the recent control strategies in literature have also been presented in this paper, including a brief explanation on the fundamental principles of the proposed strategies. Finally, this paper also presents a comparison of the strengths and weaknesses associated with the control strategies in literature.

Control Strategy of Microgrid During Grid-Connected Mode

2014

There has been a keen interest on Distributed Generation (DG) due to their restricted goals of meeting local loads and improving reliability of the overall system. Microgrids (MGs) are connected to the main grid through a Point of Common Coupling which separates the former from the latter. At the time of an intentional islanding or fault at the grid level, a microgrid is able to disconnect itself from the rest of the grid and operate by itself. A microgrid may contain both directly connected and inverter interfaced sources with different control configurations. When disconnected or islanded from the main grid there are various approaches to share the load, one of them being master-slave control where a storage device may become the reference DG to set the nominal voltage and frequency. When the main grid is brought back to normal operation, the microgrid is able to resynchronize itself to the main grid only when it meets certain conditions so as to avoid transients. All the microsou...