Keeping Things Constant

We look at two examples of how ECOTAP® VPD® helps Italian grid operator DEVAL to maintaina constant voltage in the Aosta Valley.

1 The Mall

DEVAL is ahead of the game, being part of a group in which energy production comes entirely from renewable sources. To ensure that voltage levels remain constant following the construction of a new shopping mall, the operator is switching to a VRDT.

The Aosta Valley is the smallest region in Italy. DEVAL is the largest grid operator in the local area and part of the CVA (Compagnia Valdostana delle Acque) Group, which is responsible for generating energy. The company relies on 32 hydroelectric power stations, eight wind farms, and three solar parks to deliver a total of three billion kilowatt hours of electricity every single year.

DEVAL distributes this power via a grid spanning a length of some 4,150 kilometers. Luigi Traverso, who is responsible for maintenance and development at DEVAL, explains: “We are currently working on modernizing the grid and testing new equipment that will help us to achieve even better service.” This is the case, for example, at the business park in Nus, a small town located close to the region’s capital of Aosta where a new shopping mall is currently under construction. In the area there are several solar energy systems boasting a relevant local capacity.

“It became clear to us that our existing distribution transformer would have difficulty coping with the extra voltage fluctuations. We are working on from the understanding that energy consumption is set to double within the space of a year” says Traverso. And that is why DEVAL decided to invest in a new 400-kVA transformer that takes care of voltage regulation too. When it came to the tap changer, DEVAL opted for the ECOTAP® VPD® together with the ECOTAP® VPD® Control controller and the additional CONTROL PRO module. Traverso: “We can now provide custom­ers with a stable grid even when the shops are open.”

Two locations, one solution: The ECOTAP® VPD® helps keep the grid in the Aosta Valley stable.

2 The Village

Over in Rhême-Notre-Dame in the Italian Alps—as in many other locations—DEVAL had to disconnect power twice a year to manually change the transmission ratio of the transformer. But now that’s all in the past.

The tiny village of Rhêmes-Notre-Dame, located in the Aosta region and home to 250 people, is situated in a picturesque valley. In fact, it’s the very definition of “off the beaten track.” And it’s exactly this tranquility and seclusion that draws in hundreds of tourists. During peak vacation season, the number of inhabitants shoots up and so does the demand for electricity, which comes from several hydroelectric plants and some private solar energy systems.

Therefore, power generation is as up and down as the demand. After all, there is a great deal more hydropower once the snow has melted away than after a long hot summer. Until just recently, grid operator DEVAL had to intervene on a regular basis for this reason, disconnect­ing the power and manually changing the transmission ratio of the transformer to compensate for fluctuations in the voltage to the extent possible.

Now this is in the past: “We decided to replace the old transformer with a new 250-kilovolt-ampere voltage regulation distribution transformer to test a new solution to ensure our customers a better service without any need to manually disconnect the power” says Luigi Traverso. As far as tap changing is concerned, DEVAL decided to implement the same solution as in Nus: the ECOTAP® VPD® Control controller and the additional CONTROL PRO mod­ule. “This allows us to monitor the switching operations from our control room. So far, we have observed 40 switching operations per day on average. The voltage is constant now,” says Traverso. 


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