۱- Introduction

۲- Resilience of power systems

۳- Microgrids as a resilience resource: microgrid formation

۴- Strategies used by microgrids for enhancing resilience

۵- Communication, event-specific, and component resilience

۶- Research gaps and future directions

۷- Conclusion

References

Abstract

Microgrids are considered as a potential solution to deal with major power disruption events due to their ability of islanding and potential to sustain the penetration of renewables. In order to elaborate the role of microgrids in enhancing the resilience of power systems, a three-step analysis is carried out in this paper. In the first step, the general backgrounds of resilience in power systems are presented, which comprise of disaster modeling, resilience analysis methods, and resilience enhancement efforts by different regions. In the second step, the use of microgrids as a resilience resource is analyzed, where formation of microgrids, networked microgrids, and dynamic microgrids along with resiliency of multi-energy networks are explored. In the third step, the strategies utilized by microgrids for enhancing their resilience during major outage events are analyzed. These strategies include proactive scheduling, outage management, feasible islanding, and advanced operation strategies for reducing the impact of major disruptions. The classification of these operation strategies is based on the event occurrence and clearance times. In addition, the resilience strategies used by different types of microgrids, types of energy management systems, communication resilience, and resilience of individual components in microgrids are also analyzed. Finally, research gaps in the existing literature and future directions for improving the available resilience-oriented operation methods for enhancing the resilience of microgrids are presented.

Introduction

Resilience enhancement of power grids against natural disasters has become a major consideration for power and energy sector researchers and engineers in recent years. Due to lesser incidences of natural disasters, these events were initially known as low-probability high-impact events. However, the frequency of these events has increased in the last few decades due to climate change [1]. Among various other major events, the intensity and severity of weather-related events have significantly increased in the last decades [2]. Seven of the ten major storms that occurred during the last four decades have occurred in the last 10 years and each event caused damages of over 1-billion dollars [3]. In 2017 only, eight major weather-related events have struck the world, especially the US [4–۱۱]. Five of these eight events have disrupted power to over a million consumers and the least number of consumers affected during any single event were around 0.3million. The existing electrical power systems can assure service reliability during normal conditions and abnormal but foreseeable and low impact contingencies. However, the continuity of service during unexpected and high impact events is still a challenge [12]. Therefore, existing power systems are known to be reliable but not resilient. The resiliency of a system is defined as its ability to return to the equilibrium (stable operation point) after a major disruption event [13]. Due to the absence of a universally accepted definition of resilience in power systems, the authors in [14] have analyzed various aspects of system resilience and defined the power system resilience.