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Intelligent Distribution Automation

Leitner Electro, Italy: Isolating outages

Leitner Electro chose Siemens' Distribution Automation redesign of Kronplatz Seilbahn's two 10-kilometer circuits, providing a cost-efficient and reliable grid during the busy winter season that powers ski lifts, snow-making gear, and the local economy.

Managing seasonal load differences is a major challenge for Leitner Electro, a power transmission company in northern Italy that delivers electricity to Kronplatz, one of the region’s best known ski resorts. Hourly demand goes from almost zero in the summer to as much as 10 megawatts per hour in the winter when ski-lifts and snow-making machines are going full throttle.

“In these times, operating a reliable grid is vital for the safety of skiers, for resorts trying to maintain adequate amounts of snow, and for many people whose livelihoods depend on tourism, the local economy’s biggest sector,” says Dieter Mair, a Leitner Electro project engineer.

Essential electric power reliability
Keeping the power flowing to customer Kronplatz Seilbahn, which partly owns the Kronplatz ski resort in the Dolomites near Bolzano, has become even more complicated in recent years. Several earth movements have damaged ground power cables, resulting in power outages. Repairing those damaged cables has been made more arduous by frequently violent winter storms that make access to the cables more difficult and hazardous for repair crews.

Resorts like Kronplatz also are dealing with increasing incidences and durations of little or no snowfall during winter. Therefore, to keep the slopes layered with icy powder, they must deploy snow cannons, which consume huge amounts of electric power. Winter tourism destinations no longer think of a season with light snowfall as a freak occurrence: It’s been a constant problem for much of the last decade, a trend that has made electric power reliability all the more essential.

Avoiding future outages
Kronplatz knew its resort had an aging electrical system in need of an upgrade, but a 2.5-hour outage in 2014 was the last straw. After a small slope movement caused a power line to tear, the system shut down entirely and stranded dozens of skiers in chair lifts and cable cars, which in turn produced some ugly publicity about the inconveniences many suffered. Managing Director Christian Erroi decided then and there to commission Leitner to perform a thoroughgoing review of the power infrastructure to see if there were ways of shielding it from future outages.

Leitner’s analysis led to a recommendation that Kronplatz invest in a Siemens Distribution Automation system. The technology would add new switchgears, safety modules, and routers to optimize an existing fiber optics data communications network. The circuit’s 21 substations also were updated with medium-voltage 8DJH switchgears and circuit breakers especially adapted for relatively smaller installations. A huge advantage of the Siemens Distribution Automation system was that it could be retrofitted to existing infrastructure, Mair said.

Remote fault signaling
Perhaps most importantly, the Siemens Distribution Automation technology included “remote fault signaling,” a logic software that enables the power system to identify and isolate failures in a 20-kilometer power loop. Engineers mounted new back-up systems that keep the power of the affected elements up and running.

Because switching to new auxiliary feeds can now be done remotely, the new system has reduced the former practice of sending repair crews out on three-hour trips to manually operate the switches, Mair said.

New system passes test
Mair said another improvement resulting from the upgrade with Siemens Distribution Automation was a new “visualization” computer graphics system that helps Kronplatz and Leitner handle fault management more easily.
Kronplatz did not have to wait long for the resort’s redesigned mini-grid and Siemens distribution automation to be tested. Last year, a slope movement similar to that of 2011 caused another tear of a power line and outage. Only this time, the system was back in operation within several minutes, instead of hours.

“With the Siemens system in place, everything was up and running quickly and people hardly noticed anything was wrong,” Mair saya. “I can assure you, the distribution automation system has already proven its worth.”

Text: Chris Kraul is a freelance writer based in Bogotá, Colombia.
Picture credits: Markus Günther