Resilient Distribution System by Microgrids Formation After Natural Disasters
TL;DR: A novel distribution system operational approach by forming multiple microgrids energized by DG from the radial distribution system in real-time operations to restore critical loads from the power outage to maximize the critical loads to be picked up.
Abstract: Microgrids with distributed generation (DG) provide a resilient solution in the case of major faults in a distribution system due to natural disasters. This paper proposes a novel distribution system operational approach by forming multiple microgrids energized by DG from the radial distribution system in real-time operations to restore critical loads from the power outage. Specifically, a mixed-integer linear program is formulated to maximize the critical loads to be picked up while satisfying the self-adequacy and operation constraints for the microgrids formation problem by controlling the ON/OFF status of the remotely controlled switch devices and DG. A distributed multiagent coordination scheme is designed via local communications for the global information discovery as inputs of the optimization, which is suitable for autonomous communication requirements after the disastrous event. The formed microgrids can be further utilized for power quality control and can be connected to a larger microgrid before the restoration of the main grids is complete. Numerical results based on modified IEEE distribution test systems validate the effectiveness of our proposed scheme.
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06 Apr 2017
TL;DR: The concept, metrics, and a quantitative framework for power system resilience evaluation are presented, with an emphasis on the new technologies such as topology reconfiguration, microgrids, and distribution automation and how to increase system resilience against extreme events.
Abstract: The electricity infrastructure is a critical lifeline system and of utmost importance to our daily lives. Power system resilience characterizes the ability to resist, adapt to, and timely recover from disruptions. The resilient power system is intended to cope with low probability, high risk extreme events including extreme natural disasters and man-made attacks. With an increasing awareness of such threats, the resilience of power systems has become a top priority for many countries. Facing the pressing urgency for resilience studies, the objective of this paper is to investigate the resilience of power systems. It summarizes practices taken by governments, utilities, and researchers to increase power system resilience. Based on a thorough review on the existing metrics system and evaluation methodologies, we present the concept, metrics, and a quantitative framework for power system resilience evaluation. Then, system hardening strategies and smart grid technologies as means to increase system resilience are discussed, with an emphasis on the new technologies such as topology reconfiguration, microgrids, and distribution automation; to illustrate how to increase system resilience against extreme events, we propose a load restoration framework based on smart distribution technology. The proposed method is applied on two test systems to validify its effectiveness. In the end, challenges to the power system resilience are discussed, including extreme event modeling, practical barriers, interdependence with other critical infrastructures, etc.
437 citations
TL;DR: Computational studies on the IEEE distribution test systems validate the effectiveness of the RDNP and reveal that distributed generation is critical in increasing the resilience of a distribution system against natural disasters in the form of microgrids.
Abstract: Natural disasters such as Hurricane Sandy can seriously disrupt the power grids. To increase the resilience of an electric distribution system against natural disasters, this paper proposes a resilient distribution network planning problem (RDNP) to coordinate the hardening and distributed generation resource allocation with the objective of minimizing the system damage. The problem is formulated as a two-stage robust optimization model. Hardening and distributed generation resource placement are considered in the distribution network planning. A multi-stage and multi-zone based uncertainty set is designed to capture the spatial and temporal dynamics of an uncertain natural disaster as an extension to the traditional ${N}$ - ${K}$ contingency approach. The optimal solution of the RDNP yields a resilient distribution system against natural disasters. Our computational studies on the IEEE distribution test systems validate the effectiveness of the proposed model and reveal that distributed generation is critical in increasing the resilience of a distribution system against natural disasters in the form of microgrids.
414 citations
Cites background or methods from "Resilient Distribution System by Mi..."
...and forms islanded microgrids [14], allows a DG to even...
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...network into microgrids with distributed generation (DG) units is presented in [14]....
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...resilience under natural disasters as elaborated in [12] and [14] and the necessity to coordinate the placement of DG resource placement with hardening in the distribution network planning...
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...DistFlow [11] equations are often implemented to calculate the complex power flow and voltage profile in a distribution system [11], [14], [17], [31]....
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...been extensively justified and used in both traditional distribution systems and microgrids [11], [14], [17], [31]....
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09 May 2017
TL;DR: This paper provides an introduction to the fundamental concepts of power systems resilience and to the use of hardening and smart operational strategies to improve it, and introduces the resilience trapezoid as visual tool to reflect the behavior of a power system during a catastrophic event.
Abstract: Power systems have typically been designed to be reliable to expected, low-impact high-frequency outages. In contrast, extreme events, driven for instance by extreme weather and natural disasters, happen with low-probability, but can have a high impact. The need for power systems, possibly the most critical infrastructures in the world, to become resilient to such events is becoming compelling. However, there is still little clarity as to this relatively new concept. On these premises, this paper provides an introduction to the fundamental concepts of power systems resilience and to the use of hardening and smart operational strategies to improve it. More specifically, first the resilience trapezoid is introduced as visual tool to reflect the behavior of a power system during a catastrophic event. Building on this, the key resilience features that a power system should boast are then defined, along with a discussion on different possible hardening and smart, operational resilience enhancement strategies. Further, the so-called $\Phi \Lambda {E}\Pi $ resilience assessment framework is presented, which includes a set of resilience metrics capable of modeling and quantifying the resilience performance of a power system subject to catastrophic events. A case study application with a 29-bus test version of the Great Britain transmission network is carried out to investigate the impacts of extreme windstorms. The effects of different hardening and smart resilience enhancement strategies are also explored, thus demonstrating the practicality of the different concepts presented.
309 citations
Cites background from "Resilient Distribution System by Mi..."
...Therefore, microgrids are proven to be one of the most effective ways of enhancing resilience to catastrophic events [33-37]....
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TL;DR: An appropriate framework is devised and the roles and tasks of different management entities in a multi-microgrids system are introduced and the effectiveness in confronting with different outage events is demonstrated through realistic case studies.
Abstract: This paper proposes a hierarchical outage management scheme to enhance the resilience of a smart distribution system comprised of multi-microgrids against unexpected disaster events. In this regard, after identifying the main features and requirements for a resilient outage management scheme, an appropriate framework is devised and the roles and tasks of different management entities in a multi-microgrids system are introduced. Based on this framework, the microgrids schedule their available resources in the first stage using a novel model predictive control-based algorithm. In the second stage, distribution system operator coordinates the possible power transfers among the microgrids and utilizes the unused capacities of microgrids’ resources for feeding the unserved loads in stage I. The general optimization model that needs to be run is formulated as a mixed integer linear programming problem and a novel index is presented to quantify the performance of the proposed method. The developed scheme is implemented on a test system and its effectiveness in confronting with different outage events is demonstrated through realistic case studies.
308 citations
TL;DR: A resilience-oriented service restoration method using microgrids to restore critical load after natural disasters is proposed in this paper, and the impacts of fault locations, available generation resources, and load priority on the restoration strategy are discussed.
Abstract: A resilience-oriented service restoration method using microgrids to restore critical load after natural disasters is proposed in this paper. Considering the scarcity of power generation resources, the concept of continuous operating time (COT) is introduced to determine the availability of microgrids for critical load restoration and to assess the service time. Uncertainties induced by intermittent energy sources and load are also taken into account. The critical load restoration problem is modeled as a chance-constrained stochastic program. A Markov chain-based operation model is designed to describe the stochastic energy variations within microgrids, based on which the COT is assessed. A two-stage heuristic is developed for the critical load restoration problem. First, a strategy table containing the information of all feasible restoration paths is established. Then the critical load restoration strategy is obtained by solving a linear integer program. Numerical simulations are performed on the IEEE 123-node feeder system under several scenarios to demonstrate the effectiveness of the proposed method. The impacts of fault locations, available generation resources, and load priority on the restoration strategy are discussed.
307 citations
Cites background or methods from "Resilient Distribution System by Mi..."
...It is reasonable to assume that for future smart distribution systems, this can be done by operating only remotecontrolled switches [10]....
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...In [9] and [10], microgrids energized by DGs are formed to restore load after a major outage....
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...Compared with [9] and [10], the proposed method considers uncertainties of renewable energy sources and load demand, as well as their impacts on generation resources and power flows....
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TL;DR: In this article, the problem of capacitors placement on a radial distribution system is formulated and a solution algorithm is proposed, where the location, type, and size of the capacitors, voltage constraints, and load variations are considered.
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