Remote Hardware In-The-Loop for PtG Integration

Power-to-Gas (PtG) is a technology that uses electricity to produce hydrogen through a process of electrolysis. This one can be used directly or, after appropriate conversation into syngas or methane, it can be used as chemical raw materials, burned to produce heat, or converted to electricity by means conventional gas turbines. The presence of generation from renewable sources is becoming larger and larger in our electrical systems, and this often causes the production being higher than the demand. In this context, the proper use of PtG represents an alternative energy storage to reduce the renewable curtailment. The study conducted in this thesis aims to improve the knowledge on the impact of a PtG inserted in a distribution network with the presence of photovoltaic (PV) generation, using the test technique known as Power-Hardware-In-the-Loop (PHIL). PHIL aims to replicate real-world conditions for carrying out meaningful tests on device prototypes and new technologies, like PtG, which be deployed in real energy systems. The purpose is tuning, validating and verifying the system performances or collecting data with the objective to create realistic device models – all this avoiding to deploy the device directly into the grid, which may be harmful for the grid itself, or when the device needs to be tested under uncommon conditions that may be hard to reproduce. PtG is a load, which consumes energy: for this, an interface is needed to enable power exchange. This interface is composed of a power amplifier and a set of sensors monitoring the load; the power amplifier acts as a source or user. From the simulated grid, the extraction of the values of voltage or current to control the output of the power amplifier is allowed. If a load is equipped with current or voltage sensors, it is possible to extract the current or voltage required by the load and sent them as feedback to the software grid to close the simulation loop. The first step was to develop a Simulink model that well represents the distribution network considered in the STORE&GO project. Before connecting the PtG to the simulated network, it was necessary to design the control of the power amplifier, so that the PtG can be powered at the same voltage and frequency as the simulated network. The designed control is a closed-loop type. In each cycle, this control increases the output voltage and frequency of the power amplifier until the reference values are reached. The PtG and the Power Amplifier considered in this thesis are placed at Hanze University in Groningen (NL), but thanks to a Virtual Private Network (VPN) connection, the Global Real-Time Simulations Laboratory of Politecnico di Torino can remotely control these devices through proper Simulink models. The aim was to connect the electrolyser, situated at Hanze University, to the simulated network, but this was not possible due to the Covid-19 emergency, which forced the closure of the Hanze University laboratory. As a consequence, a Simulink model of a PtG was reproduced, complete with electrolyser, storage system and methanator, by analyzing the impact of the PtG system on the network.The results show that the addition of PtG systems in a distribution network can improve the grid operation even for very high photovoltaic penetrations, by increasing its ability to host a higher penetration of non-programmable generation, giving more flexibility to the electrical system.