Inertial enhancement in the Belgian High Voltage Grid with the Virtual Synchronous Generator

The inertial response of rotating machines is an essential mechanical property of synchronous generators. It allows them to release kinetic energy from their shaft to help counteract the frequency deviation occurring during a power imbalance in the grid. The steady growth of renewable energy sources (RES) due to the current EU policies on energy transition reduces the grid inertia and jeopardizes the global grid stability. To counteract this issue, the Virtual Inertia principle consists in emulating the inertial behaviour of synchronous generators thanks to the combination of inverters and energy sources such as RES. The goal of this thesis is to study the impact of the Virtual Inertia on the frequency stability of the Belgian High Voltage Grid. The Virtual Inertia algorithm choice is made based on a litterature review. Then, the Virtual Synchronous Generator (VSG) algorithm, its simplifications and its implementation in Simulink are detailed. The second part of the modelling concerns the various power plants feeding the Belgian power network as well as the neighbouring countries and the downstream grid. A parametric analysis of the simulation results is achieved to find the optimal VSG tuning parameters. Subsequently, a generator loss and a load increase of the same rated power are compared regarding their impact on frequency. Even if the load connection is more critical on the frequency behaviour, the VSG reduces in both cases the frequency deviation and the RoCoF in an efficient way to avoid frequency issues. Thereafter, the influence of RES penetration rate is investigated. As expected, increasing RES penetration rate reduces the grid inertia, leading to greater frequency deviations and RoCoF. The VSG is efficient in reducing the RoCoF during an imbalance with the virtual inertia it provides. Finally, the economical viability of VSG on the Belgian Grid is investigated. De-loading RES and energy storage with BESS are currently not profitable. However, the frequency regulation with the BESS can easily become profitable by introducing Inertia Tariffs to remunerate the VSG for its inertial support.