Multi-parametric Optimization of Multi-functional Battery Energy Storage Operation

Smart grid is no longer a novel idea discussed only in research articles, but rather it has spawned a great amount of practical investments and applications in commercial and industrial area. One of these is a Smart Grid demonstration project implemented within Public Service Company of New Mexico (PNM) distribution network. This project combines both residential and commercial loads on a dedicated feeder, with high PV penetration ratio, equipped with a substation-sited photovoltaic (PV) system and utility-scale Battery Energy Storage System (BESS). Often renewable energy such as PV has multiple benefits, but raise reliability concerns due to their inherent intermittency. This project shows BESS could play a vital role in assisting high penetration PV connections to the power grid. Its overall goal of this project includes peak-load reduction and PV output smoothing at a specific feeder through BESS. Based on observation of the smoothing battery operation, we conducted a thorough analysis of smoothing algorithm and determined some key findings, including calculation of the power used for maintaining State of Charge (SoC), optimal size of smoothing BESS, and finally we design a new algorithm with high energy efficiency. This work addresses the primary problems for smoothing from planning to BESS operation. The results will be of value in practical implementations. This work also covers shifting algorithm in detail. The shifting optimization is constructed with three main functions: peak shaving, firming and arbitrage. It is the first time for a utility scale project that all of these three shifting functions are implemented into one platform. Islanding refers to the condition in which a location can operate autonomously with Distributed Energy Resources (DER) when power from the electric utility is absent. Both islanding mode and Grid-tied mode are discussed. The extensive field experiences and results from site operations are also demonstrated. Besides these three main functions, we also introduce several other principal shifting functions which are involved in the ongoing storage system demonstration. The control strategy and current results of modelling for this Smart Grid project are given.Electrical EngineeringDoctoralUniversity of New Mexico. Dept. of Electrical and Computer EngineeringLavrova, OlgaMammoli, AndreaLavrova, OlgaMammoli, AndreaMartínez-Ramón, ManelSorrentino, Francesc