Theoretical Analysis and Experimental Validation of Single-Phase Direct Versus Cascade Voltage Control in Islanded Microgrids (original) (raw)

Microgrid: a conceptual solution

2004 IEEE 35th Annual Power Electronics Specialists Conference (IEEE Cat. No.04CH37551)

Application of individual distributed generators can cause as many problems as it may solve. A better way to realize the emerging potential of distributed generation is to take a system approach which views generation and associated loads as a subsystem or a "microgrid". During disturbances, the generation and corresponding loads can separate from the distribution system to isolate the microgrid's load from the disturbance (providing UPS services) without harming the transmission grid's integrity. This ability to island generation and loads together has a potential to provide a higher local reliability than that provided by the power system as a whole. In this model it is also critical to be able to use the waste heat by placing the sources near the heat load. This implies that a unit can be placed at any point on the electrical system as required by the location of the heat load. Index: microgrid, distributed generation, CHP, intentional islanding, voltage droop, power vs. frequency droop, inverters

TECHNICAL CHALLENGES ON MICROGRIDS

Microgrids are becoming increasingly attractive to consumers and as such in the future, a great number of them will be installed at consumer's sites. In this situation, conventional distribution networks that accept distributed generation connections may face serious difficulty when its control and protection functions become more complicated. This incurs a burden to the network operation and some technical limitations will appear when a great number of distributed generations are installed. One way of overcoming such problems, a micro grid system is formed to provide reliable electricity and heat delivering services by connecting distributed generations and loads together within a small area. A microgrid is usually connected to an electrical distribution network in an autonomous way and employs various distributed generation technologies such as micro-turbine, fuel cell, photovoltaic system together with energy storage devices such as battery, condenser and flywheel. Micro grids can cause several technical problems in its operation and control when operated as autonomous systems. This paper is a review of three technical challenges on micro grid with respect to voltage and frequency control, islanding and protection of microgrids.

Microgrids And Distributed Generation

Intelligent Automation & Soft Computing, 2010

Application of individual distributed generators can cause as many problems as it may solve. A better way to realize the emerging potential of distributed generation is to take a system approach which views generation and associated loads as a subsystem or a "microgrid". The sources can operate in parallel to the grid or can operate in island, providing UPS services. The system will disconnect from the utility during large events (i.e. faults, voltage collapses), but may also intentionally disconnect when the quality of power from the grid falls below certain standards. Utilization of waste heat from the sources will increase total efficiency, making the project more financially attractive. University of Wisconsin Laboratory verification of microgrid control concepts are included. CE Database subject headings: CHP; distributed generation; intentional islanding; inverters; microgrid; power vs. frequency droop; voltage vs. reactive power droop.

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.

Autonomous control of microgrids

2006 IEEE Power Engineering Society General Meeting, 2006

Application of individual distributed generators can cause as many problems as it may solve. A better way to realize the emerging potential of distributed generation is to take a system approach which views generation and associated loads as a subsystem or a "microgrid". The sources can operate in parallel to the grid or can operate in island, providing UPS services. The system will disconnect from the utility during large events (i.e. faults, voltage collapses), but may also intentionally disconnect when the quality of power from the grid falls below certain standards. Utilization of waste heat from the sources will increase total efficiency, making the project more financially attractive. Laboratory verification of the Consortium for Electric Reliability Technology Solutions (CERTS) microgrid control concepts are included. Index Terms-CHP, distributed generation, intentional islanding, inverters, microgrid, power vs. frequency droop, voltage droop, 1 This work was supported in part by the California Energy Commission (150-99-003).

Microgrid systems: Current status and challenges

2010 IEEE/PES Transmission and Distribution Conference and Exposition: Latin America (T&D-LA), 2010

The objective of this paper is to present the current status and state-of-the-art of microgrid systems as well as the barriers that are being encountered for their integration to the network. The expectation about the microgrid performance is high, thus, issues related to the microgrid standards, autonomous operation, control strategies, regulatory barriers as well as its protection and islanding operation, among other aspects, will be discussed herein. Some examples of practical installations worldwide will also be presented.

Microgrid Controllers : Expanding Their Role and Evaluating Their Performance

IEEE Power and Energy Magazine, 2017

Microgrids have long been deployed to provide power to customers in remote areas as well as critical industrial and military loads. today, they are also being proposed as grid-interactive solutions for energy-resilient communities. such microgrids will spend most of the time operating while synchronized with the surrounding utility grid but will also be capable of separating during contingency periods due to storms or temporary disturbances such as local grid faults. properly designed and grid-integrated microgrids can provide the flexibility, reliability, and resiliency needs of both the future grid and critical customers. these systems can be an integral part of future power system designs that optimize investments to achieve operational goals, improved reliability, and diversification of energy sources. the key components of a microgrid are the isolating device at the point of interconnection (poi); the electric and thermal ©istockphoto.com/faithiecannoise Transmission Operations

POWER SHARING WITH INTERFACED MICRO SOURCES AMONG DISTRIBUTED GENERATION FOR RESILIENCE IN MICROGRID

Microgrid is integration of utility network along with the capability of localized power generation via distributed energy resources (DERs). Control and operation strategy of microgrid lead to selection of its optimal mode of operation. In this research work energy management system and central control unit operation is also introduced. Insight of microgrid architecture lead to selection of optimal selection of localized power generation and flow in the distributed network. Optimal selection of power flow via central controller improves resilience of microgrid by scheduling the system operation.

Microgrids as Sources of Electricity Generation in the 21st Century

The concern on climate change is driving major changes in electricity generation as well as in the pattern of consumption. By the reason of environmental considerations, large scale changes are likely to occur in the near future in transporting and distributing electricity to the end-users. Presently, the existing power grids do not meet the needs of the 21 st century because of increase in power demand, and generation complexity. Also the demand for power supply across the globe is being envisaged to rise even to the highest peak in the future. Therefore there is an immediate need for the development of highly reliable, self-regulating and efficient grid system which will allow for the penetration of distributed generators most importantly the renewable energy sources and other distributed power generation, hence the smart micro-grid technology. In this paper, behaviors of Micro-grid as regards voltage stability and droop control method are analyzed when Distributed Energy Sources (DES) are integrated.