VIZZOLA TICINO PLANT HISTORY

With the interruption of navigation between Lake Maggiore and Milan, the waters of the Ticino had been flowing unused between Sesto Calende and Tornavento since 1865.

For this reason, the "Società Italiana per Condotte d'Acqua" obtained by Royal Decree of December 6, 1886, a concession to derive through the Villoresi intake building 55 cubic meters/sec. of water, to be fed into the industrial canal of the Vizzola Ticino plant being built.

The excavation of the canal and the construction of the power plant were taken care of by the "Società Lombarda per distribuzione di energia elettrica," established in Milan on May 12, 1897 on the initiative of "Condotte" itself, Credito Italiano, the "Soc. Continentale per Imprese Elettriche" of Nuremberg and a number of private individuals.

As stated in the articles of incorporation, the "Società Lombarda per distribuzione di energia elettrica" aimed to "develop Motive Forces with the waters of the Ticino River, which now flow unused between the dam of the Villoresi Canal and the incile of the Naviglio Grande, especially to use them, transported by electricity, for the benefit of industry"; transportation was made possible by the development of three-phase alternating currents, with high voltages.

By Royal Decree of May 20, 1897, the "Società Lombarda per distribuzione di energia elettrica" was authorized to build the "Canale Industriale del Ticino, destined for the production of a powerful Force (as many as 19,000 dynamic horsepower) for the creation of electric power, for the benefit of the Lombardy area between the Ticino and the Olona," and to "derive 55 cubic meters of water from the Ticino in lean weather, with an efflux regulator at the intake basin identical to the current Villoresi. In the water competence of the new canal concurs that of the Molinara Canal of 1.5 cubic meters, included Among the lower users of the left bank of the Ticino."

In that year, the company began excavation of the canal, with a course parallel to the Villoresi and a maximum flow rate of 85 cubic meters, and had plans drawn up for the construction of the power plant, which would benefit from a 28-meter drop and flow rate of between 55 and 62 cubic meters/sec.

When completed, it turned out to be 6,853 meters long and terminated with a 1 masonry bridge-channel in the loading basin from which 10 penstocks--each 2 meters in diameter and 47.50 meters long--directed water to as many generator sets installed in the power plant's engine room, with a useful fall of 27.12 meters.

From the power plant, the water was immediately returned to the Ticino River via a 760-meter-long discharge channel.

Each group consisted of a "Francis" turbine, with a horizontal axis, and a three-phase coaxial alternator. Three groups were already operating in 1899, and the most important power lines that supplied power to industries, many of them far apart, had already been installed. Four more were added the following year.

When the power plant was inaugurated-October 9, 1901, in the presence of Victor Emmanuel III and Queen Helena-ten units were in operation and constituted the largest hydroelectric plant in Europe.

Their total installed power was found to be 16,500 kVA and they were flanked by two direct current groups for separate excitation of alternators.

In 1935, as the mechanical and electrical systems of the Vizzola power plant were worn out and technologically outdated, it was decided that they should be completely rebuilt, in relation to the expected availability of 124 cubic meters/sec of water, ensured by the imminent commissioning of the Miorina barrage to regulate the level of Lake Maggiore.

The canal rehabilitation work began in March 1937.

Its intake was enlarged, with the addition of another span and the flow rate increased from 85 to 124 cubic meters, the formation of a wide loop from the old route allowed it to be shortened by about 950 meters, maintaining its slope of 0.15%. The head of the power plant was increased to 50.13 meters, the bridge-canal was redone, and the penstocks were reduced to three, each with an inner diameter of 4 meters.

The new power plant building was also built, in whose engine room three vertical-axis units were installed, each consisting of a "Francis" turbine of 10,873 kW power (with a flow rate of 43 mc/sec.) and a 14,500 kVA three-phase "Brown Boveri" alternator.

The first unit began operation in December 1938.

The outlet channel in Ticino was widened and extended to 1,870 meters, at the confluence in Ticino it was equipped with weir and navigation lock and, at the "Lodigiani" Pumps were installed to feed the Molinara Gora.

It then formed the initial section of the Tornavento power plant canal.

 "The water pertaining to the Molinara runs through the entire canal and is taken to the engine building to be supplied to the Gora here.