Penalty Adjustment-Based Sizing Method for Flexible Resources in Isolated Microgrids

Bowei Cen,Ping Liu,Zexiang Cai,Yuanju Chen

doi:10.1109/access.2020.3046479

Bowei Cen, Ping Liu + Show 2 more

Open Access

https://doi.org/10.1109/access.2020.3046479

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Abstract

The fixed and subjective setting of the penalty coefficient is a significant drawback of existing penalty-based programming models used to determine the size of flexible resources (FRs), such as microturbines and battery energy storage systems, for isolated microgrids (IMs). Generally, most researchers set the penalty coefficient to a sufficiently large value to ensure a satisfactory operational performance of IMs, which often leads to redundant and uneconomical configurations. How to balance the operational performance and economic configuration is an intractable problem confronted by many researchers. In this paper, a penalty adjustment-based sizing method is proposed to solve the aforementioned problems. Specifically, four indicators are defined to evaluate the size of FRs. Based on the assessment metrics, a trade-off sizing method is proposed to attain the FR size with the maximum marginal benefit. This method is combined with mixed integer programming to propose a penalty adjustment-based sizing algorithm to solve the optimal penalty coefficient and size of FRs. Simulations verify that the proposed method can avoid subjectivity and improve the traditional conservative configuration.

Highlights

Isolated microgrids (IMs) are regarded as a highly efficient way to supply power in remote and unconnected areas [1]
In contrast to the existing literature, in which the penalty coefficient is used as a parameter, this paper sets the range of the penalty coefficient and solves for the optimal penalty coefficient under the formulated constraint as follows
This drawback can be overcome using the proposed penalty adjustment-based sizing method to determine the size of Flexible resources (FRs) with the maximum marginal benefit under the given limitations of the RCR AND LCR, which strikes a balance between operational performance and economic configuration

Summary

INTRODUCTION

Isolated microgrids (IMs) are regarded as a highly efficient way to supply power in remote and unconnected areas [1]. To guarantee the power supply reliability and renewable energy consumption ability of IMs, the size of FRs is generally determined conservatively, which results in an uneconomical configuration [11], [12]. Approaches that can result in a trade-off between robustness and cost remain lacking Motivated by these findings, in this paper, we focus on the single-objective optimization problem and investigate methods to improve the conservative configuration and fixed setting of the penalty. A size assessment system is constructed for FRs. The system includes four indicators representing the power supply reliability, renewable energy consumption ability, operation robustness of the IMs and economy of the configuration. The proposed size assessment system for FRs contains four indicators that represent the power supply reliability, renewable energy consumption ability, operational robustness of IMs and economy of the configuration. In the formula, cMT denotes the cost of the unit power capacity of the MTs, cP denotes the cost of the unit power capacity of the BESS and cE denotes the cost of the unit energy capacity of the BESS

MARGINAL-BENEFIT FUNCTION

TRADE-OFF SIZING METHOD

DISCUSSION OF PENALTY

SOLUTION ALGORITHM

CONCLUSION