New synchronous condenser - Flywheel systems for a decarbonized sardinian power system

The decarbonization process of the Sardinian network will lead to the shutdown of the existing coal power plants, significantly reducing system inertia. This will also affect the operation of the - now crucial - HVDC links connecting the Sardinian system to the European transmission network, due to the lower short circuit ratio as well as to possible commutation failure issues. Among other measures aimed at coping with this issues Terna, the Italian transmission system operator, is installing two new Synchronous Condensers / Flywheel Systems (SCFSs) in Selargius 400 kV substation. The paper presents a first assessment of the SCSF performance in supporting the operation of the decarbonized Sardinian system. Electromagnetic transient and dynamic simulations show that properly sized SCFSs can be instrumental in ensuring the correct operation and quick recovery of the Sardinian HVDC terminals following AC network faults.