Fätschbachwerk
| Fätschbachwerk | ||
|---|---|---|
 |
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| location | ||
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| Coordinates | 718 008 / 197210 | |
| country |
 Switzerland
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| place | Linthal GL | |
| Waters | Fätschbach | |
| Height upstream | 683.2 m above sea level M. | |
| power plant | ||
| owner | Axpo Power | |
| Start of planning | 1944 | |
| construction time | approx. 3 years (18 months without interruptions in winter) |
|
| Start of operation | October 13, 1949 | |
| technology | ||
| Bottleneck performance | 14.5 megawatts | |
| Average height of fall |
625 m | |
| Expansion flow | 3 m³ / s | |
| Standard work capacity | 74.4 million kWh / year | |
| Turbines | 1 × Pelton turbine 10 MW 1 × Pelton turbine 5 MW |
|
| Others | ||
| was standing | 2018 | |
The Fätschbachwerk is a high pressure - Laufwasserkraftwerk at Linthal , which with the water of Fätschbachs is operated. It replaced the Fätschli power plant that went into operation in 1901 and has been supplying electricity since October 13, 1949.
history
During the Second World War the idea arose to make better use of the water from the Fätschbach. The power plant that existed at that time used only part of the available gradient and was dimensioned for the minimal runoff in winter, which meant that a lot of water remained unused in the summer. The preliminary project began in 1944, in November 1946 the Nordostschweizerische Kraftwerke (NOK) acquired the concession and in October 1949 electricity was generated for the first time.
Compared to the old one, the new power plant has a 14 times greater output and 12 times greater annual production. However, ¾ of the annual production occurs in the six summer months. The old Fätschli power plant was shut down, for which the NOK provided replacement energy to the Linthal community.
With the construction of the Linth-Limmern (KLL) power plant, the nacelle was enlarged in 1964 so that the Linthal stage turbines of the aforementioned power plant could be accommodated in the same nacelle.
Technical equipment
Water intake
The water intake of the Fätschbach lies next to the Klausenstrasse at 1305 m above sea level, only about 150 m after the border with the canton Uri, where the Urnerboden narrows to a gorge. The water is returned a little below the mouth of the Fätschbach in the Linth at a height of 675.6 m, which results in a usable gradient of 629.4 m. The weir forms a six-meter-deep pond with a capacity of 10,000 m³, which is used to compensate for fluctuations in the daily inflow or to collect water to meet peak energy requirements when the outflow is low . The amount of water in the reservoir can be completely processed by the power plant in one hour.
At the point of the water intake, the valley consists of fissured Upper Jurassic limestone on the right and sacking material on the left . The weir of the water intake is therefore on the right side of the valley directly on the rock, on the left on a 21 m deep sealing wall. The valley is also sealed by a 25 m deep sealing screen made of cement injections . The effectiveness of this method, which was still new in the construction of the power plant, was observed particularly closely, as it was to be the basis for the construction of the dam of the Limmernsee , where similar geological conditions were expected and cement injections were later used on a large scale.
The water intake also serves as a settling basin for the sand carried along by the Fätschbach. The basin is cleaned during floods when the plant has to be shut down anyway. In this case, which are protecting the weir open and the sand washed into the Fätschbach.
Supply line
The supply line to the water lock consists of two penstocks and an intermediate pipe. The inlet structure is located on the right side of the water intake and flows into a 300 m long pressure tunnel in the rock on the right side of the valley. This is followed by a 590 m long pipe made of concrete pipes with a diameter of 1.2 m, which crosses the Fätschbach with an aqueduct and follows Klausenstrasse. The subsequent 2.3 km long pressure tunnel leads under the Klausenstrasse and follows the left side of the valley to the moated castle. A special feature of the power plant is that this tunnel is designed to rise, creating a 3.2 km long culvert between the water intake and the water tower . At the lowest point of the culvert there is an emptying with a scree trap. The tunnel was driven mechanically, using tunnel excavators. Jacking rates of up to eleven meters per day were achieved.
The one-kilometer-long pressure line leads from the moated castle through a steep slope endangered by avalanches and rockfalls, which is why several changes to the design, the gradient and the direction were necessary. The first 200 m lead into a pipe tunnel through rock. In addition to the pressure pipe, space was left in the tunnel for a cable car. This is followed by a section where the line follows the terrain in a trench before disappearing into a second 108 m long tunnel. The last section up to the machine house is designed as a line in a trench. The steel pipes in the upper part of the pressure line were supplied by the boiler forge Kerag from Richterswil , the lower part by Sulzer from Winterthur , with wall thicknesses of up to 25 mm.
Machine house
Two horizontal Pelton turbines of different sizes were installed in order to be able to process the water volume, which varies greatly depending on the season, with good efficiency . The larger turbine is equipped with two nozzles. It can process 2 m³ / s and has an output of 13,450 hp, the smaller one processes 1 m³ / s with just one nozzle and has an output of 6,800 hp. Both turbines and the associated ball valves were supplied by Bell Maschinenfabrik from Kriens .
The air-cooled generators were supplied by Maschinenfabrik Oerlikon , the large one has an output of 13,000 kVA , the small one 6,500 kVA. Both generators were equipped with a CO 2 extinguishing system from the start .
Water return
The underwater is discharged into a 10,000 m³ compensation basin. Its task is to discharge the water from the power station into the Linth in accordance with the natural runoff of the Fätschbach. This means that the hydropower plants further down the valley are not influenced by the peak operation of the Fätschbachwerk when the water level is low.
Headquarters Linthal
In 1964, the Linthal headquarters of the Linth-Limmern power plants went into operation, the two Francis turbines of which are housed in the expanded machine house of the Fätschbach plant. For the water return of these two machines, a separate compensation basin with a capacity of 220,000 m³ was created north of the existing compensation basin of the Fätschbachwerk.
literature
- A. Sonderegger: The Fätschbachwerk. 1st part: disposition and construction facilities . In: Schweizerische Bauzeitung . tape 69 , 1951, doi : 10.5169 / seals-58850 .
- E. Elmiger: The Fätschbachwerk. Part 2: The mechanical and electrical systems . In: Schweizerische Bauzeitung . tape 69 , 1951, doi : 10.5169 / seals-58859 .