Optimal Grid Supporting Power-to-Gas (GS-P2G) Concept for Grid Voltage and Frequency Regulation

Abstract

This paper presents an optimal grid-supporting power-to-gas (GS-P2G) control scheme that coordinates the operation of a grid-forming inverter (GFMI), battery energy storage (BES), and hydrogen energy storage (HES) in a power-to-gas (P2G) system. The design aims to optimally maintain the steady state of the active power flow under critical conditions by smoothing the fluctuating power that flows to the grid from renewable energy sources (RES). P2G contributes to procuring hydrogen supply systems in areas with low-density transmission networks and gas-supply infrastructure. For instance, P2G energy could originate from the RES, which would otherwise be curtailed depending on the network constraints. Furthermore, to prevent waste, HES and existing natural gas networks can potentially store and reuse this energy. The GS-P2G control concept enables GFMI to respond rapidly to the intermittency and variability of wind power, cover the power surplus/deficits by charging/discharging the BES, and prevent the grid voltage and frequency from deviating away from the normal ranges. Therefore, the optimized control scheme presented in this article combines the power management system (PMS) and grid support function with an optimization function for highly RES-penetrated areas. The measured experimental results were evaluated and briefly discussed to demonstrate the performance and feasibility of the proposed control scheme.INDEX TERMS Grid forming, grid support, optimal control, power management, power-to-gas. NOMENCLATURE Abbreviations P2GPower to gas GS-P2G Grid supporting power to gas GFM Grid forming GFMI Grid forming inverter RES Renewable energy source SGs Synchronous generators VSG Virtual synchronous generator BES Battery storage system BES-C Battery storage system converter HES Hydrogen storage system HES-CHydrogen storage system converterThe associate editor coordinating the review of this manuscript and approving it for publication was Nagesh Prabhu .