Introducing Storage Operators for Coordinating Residential Batteries in Distribution Networks Under Time-of-Use Tariffs and Adaptive Power Limits

Abstract

The transition towards Time of Use (ToU) tariffs has become a promising solution for addressing power system challenges resulting from increased installations of renewable energy systems. ToU tariffs encourage residential Battery Energy Storage System (BESS) adoption to reduce customers’ bills through maximizing energy storage during low-price intervals (e.g., middle of the day). However, simultaneous BESS charging affects diversity of load, which may lead to the violation of distribution networks constraints. Traditional network management with conservative fixed power limits leads to inefficient network capacity use since charging capacity is reserved for BESS facilities which remain in idling states after fulfilling their charging requirements. To better allocate the capacity of distribution networks to active BESS facilities (charging/discharging), this work introduces an independent storage operator to coordinate BESS control actions by employing time-varying and adaptive power limits. For this purpose, a Mixed Integer Linear Programming (MILP) algorithm is proposed for storage operator to manage BESS facilities while respecting network constraints and customers’ desired bills. At each time step, the algorithm decides power limits for active BESS facilities based on predefined linear functions. These functions are generated offline by using Optimal Power Flow (OPF) to establish relationships between power limits and number of active BESS. The application of the algorithm to a real Jordanian distribution network demonstrates its effectiveness in allowing for a larger number of customers achieving their desired bills compared to using fixed power limits.

Keywords: Battery Energy Storage System (BESS), distribution networks, Optimal Power Flow (OPF), storage operator, Time of Use (ToU) Tariff