Robust Microgrid Scheduling With Resiliency Considerations

Guodong Liu,Yichen Zhang,Kevin Tomsovic,Thomas Ben Ollis,Tao Jiang

doi:10.1109/access.2020.3018071

Abstract

A new microgrid scheduling model with resiliency guaranteed under the risk of both utility failure and prevailing uncertainties of renewable generation and load is proposed in this article. The proposed model minimizes the overall operating cost of the microgrid by efficiently coordinating the power supply from local distributed energy resources and the main grid. The resiliency is ensured by maintaining certain amount of flexibility in local distributed energy resources, which can be quickly deployed to keep the power supply uninterrupted whenever the utility grid suddenly goes down. In addition, the uncertainties of renewable generation and load are captured with the proposed two-stage robust optimization model. By solving the proposed optimization, the solution not only guarantees the resiliency of the microgrid by supporting possible islanding incidents without load interruption, but also ensures robustness against the randomness of renewable generation and load. Results of case studies on a typical microgrid demonstrate the effectiveness of the presented robust microgrid scheduling model.

Highlights

Resilience is the ability of power systems to prepare for and adapt to low-probability, high-impact incidents and withstand and recover rapidly from disruptions
One viable solution for improving power system resiliency is to deploy microgrids, which are groups of interconnected distributed generators (DGs), energy storage systems (ESSs), and colocated loads with the ability to intentionally disconnect from the main grid and continue to supply the islanded portion of the grid without any interruption [2]
Considering the majority of the enlarged forecast errors in renewable generation and loads need to be handled by adjusting the output of dispatchable DGs since the power at point of common coupling (PCC) is subject to the resiliency constraints, the generation cost of dispatchable DGs is relatively high comparing with the utility rate at PCC, the total operating cost of the microgrid will necessarily rise as as the level of uncertainties increases

Summary

INTRODUCTION

Resilience is the ability of power systems to prepare for and adapt to low-probability, high-impact incidents and withstand and recover rapidly from disruptions. The prevailing uncertainties regarding renewable generation and loads could significantly impact microgrid optimal scheduling, the imported/exported power at the PCC, the commitment and dispatch of DGs, and the charging/discharging of ESSs, which further affect the success of islanding. These uncertainties complicate the resilient operation problem considerably by transforming it into a multi-level optimization, which is very challenging to solve. (10) – (14) are proposed to ensure sufficient spare capacity and high enough ramping speed of committed dispatchable DGs and ESSs are maintained to mitigate the change of power at the PCC in case the utility supply is interrupted By this way, the microgrid is prepared for and could rapidly adapt to the failure of utility grid at any time. Τ is in the fault duration when no backup generators are installed in the microgrid

ROBUST MICROGRID SCHEDULING WITH RESILIENCY CONSTRAINTS

Findings

CONCLUSION