Terna: “Restarting” the power grid
Last April, Terna, the Italian power grid operator, conducted a “restart” test on more than 1,400 km of high-voltage power lines, from the city of Villarodin in France to Brindisi in South Italy (Puglia region). Assisted by Enel Produzione, 120 Terna technical staff members checked the readiness of the power grid with a test that ran from the Villarodin electrical substation in France right down to the Brindisi Sud station, covering six Italian regions: Piedmont, Liguria, Tuscany, Lazio, Campania and Puglia. It was all done in record time: just 35 minutes to “restart” Italy from the northern border to the south. Operations like these are needed to check on the electricity system’s conditions and improve quality and security.
All the network elements were tested in terms of the functioning that under emergency conditions must ensure restoration of service and coordinated management of the disruption with the foreign network operator. The test proved and confirmed that in the event of a widespread power outages, energy could be restored to the main national production centres, starting from outside the country and continuing along an “electricity highway” to cover all of Italy. The success of the test opens new avenues for rapid recovery strategies in electricity services and confirms that it is possible to create an electricity highway linking the north and south of the peninsula in a very short time. The Italian electricity grid responded successfully to the test, confirming its extreme flexibility and reliability, as well as its technical excellence.
The event in France is just one of the latest tests of this kind carried out on the power grid to improve quality and safety, but it is the first time that a test was done in France to “restart” the Brindisi power plant. Since 2012, Terna has successfully carried out similar tests, both on this artery (Villarodin-Brindisi) and on the line from Switzerland, and also in Tuscany, Veneto, Sicily and Sardinia. It was in fact on Italy’s largest island that Terna conducted a similar test in early June 2017. The restart test in this case involved 200 km of Sardinian power lines in the provinces of Sassari and Nuoro and required 50 technical staff from Terna, Enel Green Power and e-distribution. The exercise saw Terna’s first ever use of modern synchronous condensers, installed in Codrongianos, and the first-time use, imported from the mainland, of the direct-current Sa.Co.I. connection. The restart artery involved Enel Green Power’s “Taloro” hydroelectric power station, with its 240 MW and 8 e-distribution primary transformer rooms, which supply about 80,000 customers. The tests, lasting less than two hours, evaluated the timing and procedures for the re-powering and restarting of the power generation plants and the flexibility of the Sardinian electricity grid, which responded very well. Testing of this type is very important particularly in a region like Sardinia, a context characterised by delicate balances due to the high development of renewable sources. Previously, Terna had run similar kinds of tests on the Sardinian electricity grid in 2013 but they involved different lines and grid elements (production units, electrical substations, etc.).