A Multi-Timescale Two-Stage Robust Grid-Friendly Dispatch Model for Microgrid Operation

Jiayu Han,Zuyi Li,Lei Yan

doi:10.1109/access.2020.2973622

Abstract

Uncertainty in renewable energy generation and load consumption is a great challenge for microgrid operation, especially in islanded mode as the microgrid may be small in size and has limited flexible resources. In this paper, a multi-timescale, two-stage robust unit commitment and economic dispatch model is proposed to optimize the microgrid operation. The first stage is a combination of day-ahead hourly and real-time sub-hourly model, which means the day-ahead dispatch result must also satisfy the real-time condition at the same time. The second stage is to verify the feasibility of the day-ahead dispatch result in worst-case condition considering high-level uncertainty in renewable energy dispatch and load consumptions. In the proposed model, battery energy storage system (BESS) and solar PV units are integrated as a combined solar-storage system. The BESS plays an essential role to balance the variable output of solar PV units, which keeps the combined solar-storage system output unchanged on an hourly basis. In this way, it largely neutralizes the impact of solar uncertainty and makes the microgrid operation grid friendly. Furthermore, in order to enhance the flexibility and resilience of the microgrid, both BESS and thermal units provide regulating reserve to manage solar and load uncertainty. The model has been tested in a controlled hardware in loop (CHIL) environment for the Bronzeville Community Microgrid system in Chicago. The simulation results show that the proposed model works effectively in managing the uncertainty in solar PV and load and can provide a flexible dispatch in both grid-connected and islanded modes.

Highlights

Sustainability, security and environmental protection are three important goals for modern power systems
SIMULATION RESULTS IN GRID-CONNECTED MODE we examine the effectiveness of the proposed model for Bronzeville Community Microgrid (BCM) in the grid-connected mode
The total cost in the worst case is the same as the one in the grid-connected mode since the most important task for the battery energy storage system (BESS) unit is to maintain the total power of the solar-storage system, which means for the same uncertainty rate, the BESS unit is capable of balancing the same amount of deviation from the solar PV output

Summary

INTRODUCTION

Sustainability, security and environmental protection are three important goals for modern power systems. Reference [20] proposes an optimal coordination strategy, which uses a multi-timescale model for isolated power systems. Reference [22] proposes a multi-timescale and robust energy management and the scheme is divided into a day-ahead and an intraday model. The day-ahead scheduling model in [23] considers uncertainty of wind and solar power by multi-scenarios and applies dispatch schemes of different timescales in realtime dispatch. Reference [30] provides operation strategies considering uncertainties based on double deep Q-learning method It needs the large number of data to train a model and these models are easy to be attacked [31]. The results can be used for day-ahead dispatch considering uncertainty in both grid-connected and islanded modes and have enough regulating reserve to satisfy real-time dispatch constraints

MATHEMATICAL FORMULATION AND SOLUTION APPROACH

2) OBJECTIVE FUNCTION

RTDS-BASED TESTING OF THE PROPOSED MODEL

Findings

CONCLUSION