Italy boosts grid resilience with synchronous compensator systems

Italian transmission system operator Terna has ordered two static synchronous compensator (STATCOM) systems from Siemens Energy to boost grid stabilisation as the country moves away from conventional power.

As energy demand increases and more renewable energy comes online to meet this demand, Italian grid operators need to mitigate the volatility and intermittency associated with renewable sources.

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To this end, the four Flexible AC Transmission Systems (FACTS) from Siemens Energy will stabilise voltage fluctuations by acting as either a source or sink of reactive power depending on the requirements of the Italian grid. They will significantly reduce the risk of voltage drops and blackouts. In addition to reactive power, the synchronous condensers will also provide short circuit power and inertia – both urgently needed to compensate for fewer conventional power plants.

The two new STATCOM systems, part of Siemens Energy’s SVC PLUS series, will be built in Villanova (Abruzzo region) and Latina (Lazio region) and will contribute to interconnections between Italy and Montenegro and mainland Italy and Sardinia.

System spec

The synchronous condenser solution uses a conventional generator to provide the short circuit contribution and enlarge the necessary inertia by coupling a loss optimised flywheel to the rotating mass of the rotor. In this way, they help stabilise network frequency. The first synchronous condenser in Fano is planned to be commissioned at the end of 2021, and the second in Rosara in October 2022. The two STATCOM systems will be commissioned in June 2022.

Image credit: Siemens Energy

They will be delivered as an innovative space-saving containerised solution, which also reduces project execution time and effort by avoiding building approval procedures. Earlier, Terna ordered two synchronous condenser plants that are now under construction in Fano and recently in Rosara (both Marche region).

“Grid operators like Terna have the tremendously important roles of reconverting and redesigning the electricity infrastructure to meet decarbonisation targets without compromising grid stability and reliability,” said Beatrix Natter, Executive Vice President Transmission at Siemens Energy. “Our state-of-the-art grid stabilisation technologies will help Terna to manage the growing complexity of the electricity system and offer an efficient, secure, and sustainable Italian grid.”

The two STATCOM systems based on Siemens Energy’s SVC PLUS technology operate with 125 megavolt-ampere reactive (Mvar) each at 400 kilovolts and will be the first completely containerised STATCOM solution at this voltage level.

The key benefits for Terna include reduced space requirements and simplified construction permits.