Risk-Constrained Microgrid Reconfiguration Using Group Sparsity

TL;DR

This paper presents a convex, risk-aware microgrid reconfiguration method that incorporates group sparsity to efficiently handle line switching decisions under renewable generation uncertainties.

Contribution

It introduces a convex reformulation of the chance-constrained reconfiguration problem using group sparsity and scenario approximation techniques, enabling distributed solutions.

Findings

Convex reconfiguration scheme handles LOL and ampacity constraints.

Scenario approximation makes the problem computationally feasible.

Distributed solution via ADMM is possible for multi-facility management.

Abstract

The system reconfiguration task is considered for existing power distribution systems and microgrids, in the presence of renewable-based generation and load foresting errors. The system topology is obtained by solving a chance-constrained optimization problem, where loss-of-load (LOL) constraints and Ampacity limits of the distribution lines are enforced. Similar to various distribution system reconfiguration renditions, solving the resultant problem is computationally prohibitive due to the presence of binary line selection variables. Further, lack of closed form expressions for the joint probability distribution of forecasting errors hinders tractability of LOL constraints. Nevertheless, a convex problem re-formulation is developed here by resorting to a scenario approximation technique, and by leveraging the underlying group-sparsity attribute of currents flowing on distribution lines equipped with tie and sectionalizing switches. The novel convex LOL-constrained reconfiguration scheme can also afford a distributed solution using the alternating direction method of multipliers, to address the case where multi-facilities are managed autonomously from the rest of the system.