Participation in the Frequency Regulation Control of a Resilient Microgrid for a Distribution Network (original) (raw)

Implementation of interactivity across a resilient microgrid for power supply and exchange with an active distribution network

CIRED Seminar 2008: SmartGrids for Distribution, 2008

This paper presents the results of a research project whose objective is to extend obtained capabilities of a resilient microgrid to a conventional distribution network. This system has been previously sized and optimized to fully operate in an autonomous way. The presented work is an advanced interface control system for grid connection of this cluster in order to provide the over power in compliance with the distribution network. As a result, the Distribution System Operator considers this locally controlled cluster as a single producer.

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.

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.

A Comprehensive Review on Modeling, Control, Protection and Future Prospects of Microgrid

Imminent constraints such as sky rocketing energy costs and need for expansion of generation & distribution systems attributable to increase in demand of power has led to revolution in generation system and evolution of Microgrid concept. Various operating principles and configuration of Microgrid are discussed in this paper focusing its operation in grid tied as well standalone operation mode. Possible controlling schemes and protection strategies are also suggested in this paper keeping in mind expected future prospects and challenges that can come in way while interfacing Microgrid with the main utility grid.

The Evolution of Research in Microgrids Control

IEEE Open Access Journal of Power and Energy, 2020

Microgrids (MGs), as novel paradigms of active Distribution Networks, have been gaining increasing interest by the and constitute an active area of research community in the last 20 years. Currently, they are considered as key components in power system decentralization, providing viable solutions for rural electrification, enhancing resilience and supporting local energy communities. Their main characteristic is the coordinated control of the interconnected distributed energy resources (DER), which can be realized by various methods, ranging from decentralized communication-free approaches to centralized ones, where decisions are taken at a central point. This paper provides an overview of this development focusing on the technical control solutions proposed for the various levels of their organization hierarchy. A critical assessment of selected, promising technologies is provided and open questions regarding the trend to more decentralized power systems are discussed.

Protection coordination in grid connected & islanded modes of micro-grid operations

2013 IEEE Innovative Smart Grid Technologies-Asia (ISGT Asia), 2013

In this paper the authors tried to design a under excitation limiter and a power system stabilizer which can operate without any kind of interaction. The under excitation limiter (UEL) is intended to prevent reduction of generator excitation to a level where the steady state stability limit or the stator core end-region heating limit is exceeded. The power system stabilizer (PSS) uses auxiliary stabilizing signals to control the excitation system so as to improve power system dynamic performance.

Dynamic Frequency and Overload Management in Autonomous Coupled Microgrids for Self-Healing and Resiliency Improvement

IEEE Access

Autonomous microgrids (MGs) are being installed in large remote areas to supply power where access to the utility grid is unavailable or infeasible. The power generation of such standalone MGs is largely dominated by renewable based energy sources where overloading or power deficiencies can be common due to the high intermittency and uncertainty in both load and power generation. Load-shedding is the most common mechanism to alleviate these problems to prevent system instability. To minimize load-shedding, most MGs are equipped with local battery energy storage (BES) systems to provide additional support. Furthermore, in the event of severe overloading or when BES capacity is insufficient to alleviate the overload, neighboring MGs can be provisionally coupled to provide mutual support to each other which is a more effective, economic and reliable approach. Such a coupling is preferred to be via power electronic converters to enhance the autonomy of the MGs. This paper proposes a two-stage, coordinated power sharing strategy among BESs and coupled MGs for overload management in autonomous MGs, through dynamic frequency control. Both local BES and the neighboring MGs can work in conjunction or individually to supply the required overload power demand. For this, BES' state of charge should be above a minimum level and extra power generation capacity needs to be available in the neighboring MGs. A predefined framework with appropriate constraints and conditions, under which the power exchange will take place, are defined and formulated. The proposed mechanism is a decentralized approach, operating based on local frequency and state of charge measurements, and without any data communication amongst the MGs. The dynamic performance of such a network, is evaluated through extensive simulation studies in PSIM R and verifies that the proposed strategy can successfully alleviate the overloading situation in the MGs through proper frequency regulation. INDEX TERMS Battery energy storage, dynamic frequency control, interconnection converter, coupled microgrids, overload management.

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.

Survivability of Autonomous Microgrid During Overload Events

IEEE Transactions on Smart Grid, 2019

Grid-forming sources are voltage sources that draw necessary currents to meet any load changes. A load step can cause part or all of these sources to become overloaded in a microgrid. This paper presents an overload mitigation controller that addresses the two overload issues in a microgrid by actively controlling the sources' frequency. When part of the sources in a microgrid is overloaded, the controller autonomously transfers the extra load to other sources by rapidly reducing its frequency. The frequency difference between sources during transient results in a change of phase angle, which redistributes the power flow. When all sources in a microgrid are overloaded, each source keeps dropping the frequency. Therefore, under frequency load shedding can be used to trip the non-critical loads resulting in the survival of microgrid. The advantages of these concepts are that communications between sources are not needed during transient, and the robust voltage control is maintained. Simulation and field tests from CERTS/AEP microgrid test site verify that the control strategy is effective in both purely inverter-based microgrids and inverter & generator mixed microgrids.