Val d’Aosta - Free surface channels and innovative monitoring systems

The main mission of the Compagnia Valdostana delle Acque (CVA) is the production of clean energy, while sustainability is its tangible commitment to the well-being of people and the environment. This company transforms the power of water, sun and wind into 2.9 billion kWh per year, preserving the territory and the natural ecosystem. 

Among the company’s main assets, there are canalizations and hydroelectric power plants managed and designed to use and enhance water resources in mountain areas, as a result of an unbreakable bond between man and water from which the electricity arriving in our homes is generated. This relationship, rich of history, culture and mutual respect, and which for some years has also involved CAE, combines the generation of energy with the constant protection of the Alpine environment.

The monitoring systems, aimed at keeping the water level under control along the channels conveying the resource to the hydroelectric power plants, were installed on two specific plants: “Chavonne” and “Hône 2”.

The Chavonne run-of-the-river power plant went into operation in 1922. Unlike what would be expected, it is not located near the riverbed, but halfway up the slope in order to discharge the swirled waters into the derivation channel of the Grand Eyvia power plant, for the benefit of the latter and the Aymavilles plant. The Chavonne power plant derives its waters from the Grand Eyvia, to which the waters of the Nomenon and, subsequently, those of the side valley of the Savarais are added, through a long tunnel. The Chavonne plant produces renewable hydroelectric energy and is capable of delivering 7 m³ per second to the 5 Pelton turbines installed, reaching a total power of 27 MW altogether.

The run-of-the-river hydroelectric plant of Hône 2, located in the homonymous municipality, is characterized by a 12,830 meter long derivation channel, built halfway up the slope following the contour lines of the steep sides of the Ayasse stream valley. Some sections of the channel were built in a tunnel to overcome the precipices of rock and, at the same time, to protect it from landslides and avalanches. The plant uses the energy of the water coming from the streams of the catchment basin. During the winter, the waters released by the Miserin and Vercoce lakes are added. The hydroelectric power plant is equipped with three Pelton turbines with a flow rate of 2 m³ per second. This equipment guarantees the plant a total power of 11 MW.

The correct functioning of these two plants is closely related to the good health of the approximately 30 kilometres of free surface and partially covered channels which flow from and towards the plants. CVA has always paid a lot of attention precisely to these infrastructures, with significant and continuous investments, as well as monitoring and maintenance programs. CAE's contribution is aimed at strengthening these activities, with the preparation of near real-time hydrometric monitoring spots along these channels. In this perspective, the company considered essential to have an adequate volume of data on water levels in the channels along their entire path.

Between November 2018 and November 2019, for each intervention site the following activities were carried out:

- specific operational surveys to verify installation conditions;

- communication tests with CAE ACTI-Link radio modules, wireless technology, as well as the automatic stations provided;

- check of UMTS/GPRS signal, to allow remote viewing and transmission of data to the Control Centre located on the regional territory.

Both for the Hône 2 intake channel and the Chavonne channels, all required adjustments were carried out following the above-mentioned tests, and the piezometers were installed during the maintenance and emptying procedures of the channel.

Altogether, for these two projects the following equipment was therefore installed:

- n. 33 measurement spots, for the acquisition of the water level through piezometric measurements using PLM10 sensors and ACTI-Link modules for wireless connection of the measurement spots, as well as the intake structure and the Control Centre;

- n. 4 Mhaster datalogger acquisition stations with solar panel and backup batteries, two for each plant, capable of wireless connection to each of the measurement spots.

Completing the technological monitoring equipment provided by CAE to CVA, there are also 2 automatic thermo-pluviometric stations, installed near Poignon and Fenille.

The CVA Acquisition Centre collects data via routers through the use of DATALIFE software, for the acquisition, management, communication and interaction via GPRS between the various components of the monitoring system provided by CAE.

The displaying of the collected data is available on site on the station's LCD screen or remotely via the Web Server installed on each data-logger, as well as remotely and on an aggregated basis via AEGIS, a web based software which is accessible and compatible with the most common browsers upon authentication and which allows the geo-spatial representation of the information from the monitoring and early warning system. DATASCAPE also operates in the same control unit for Open data sharing with standard interfaces based on Web Server with RESTful technology;

Completing the set of specific software for the monitoring systems, there are also tools for setting thresholds for each individual measurement spot, through a specific section of the website included in the Mhaster station. Data can in fact be collected in order to analyse trends and ensure that the water level is below a certain threshold. If the pre-established threshold is exceeded, signals can be triggered via notification or SMS.

Moreover, 2 workstations are also provided for data acquisition and display, one in Châtillon at the CVA Civil Engineering offices, and the other one in Chavonne at the hydroelectric power plant.

From December 1st, 2020, CAE has been carrying out maintenance on the hydro-meteorological stations located in the high mountains in the Autonomous Region of Valle d’Aosta.

In this regard, CVA chose CAE not only for the unquestioned quality of its equipment, but also because it has already tested our company’s efficiency in corrective and preventive maintenance, as well as for the guaranteed 24/7 assistance we offer with specialized technicians, both from remote and on field. 

To keep the system going in the best possible way and to limit malfunctions, CAE offers 12 months warranty, including materials and labour force for all failures caused by manufacturing or installation faults.



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