Wägital power plant
| Wägital power plant | ||
|---|---|---|
 |
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| location | ||
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| Coordinates | 710 783 / 225 562 | |
| country |
 Switzerland
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| place | Siebnen , Rempen , Innerthal | |
| Waters | Wägitalersee , Rempen basin | |
| power plant | ||
| owner | Northeast Swiss power plants & electricity station of the city of Zurich | |
| operator | AG Kraftwerk Wägital | |
| Start of planning | 1911 | |
| construction time | 1922-1926 | |
| Start of operation | 1924/1926 | |
| technology | ||
| Average height of fall |
Upper level: 203–260 m Lower level: 176–197 m |
|
| Turbines | 8 Francis turbines | |
| Generators | 8 three-phase synchronous machines | |
| Others | ||
The Wägital power plant (until 1974 the Wäggital power plant ) is a pumped storage hydropower plant in the canton of Schwyz . The plant is designed in two stages and was the largest pumped storage power plant in the world when it was commissioned. The power plant is one of Wägitalersee whose dam was the highest in the world in Schräh when construction is completed. The power plant was built between 1922 and 1926, although partial operation has been possible since 1924.
history
The history of the power plant begins in 1895, when the so-called Wetzikon consortium set the goal of building a power plant in the water-rich and topographically favorable Innerthal . As a result, the district municipality granted water rights concessions in 1896 and 1898. The first project was created in 1899, this included a 25 meter high earth dam on the lower half of the valley behind the Schlierenbach delta. From there, the water was to be led in tunnels to the turbines in Siebnen . In 1911, the planning of today's power plant began and the project was ready for construction between 1916 and 1921. On November 25, 1921, the joint stock company Kraftwerk Wäggital was founded, and the official start of construction in the spring of 1922.
operator
The power plant was built by AG Kraftwerk Wäggital . The company was owned equally by the Nordostschweizerische Kraftwerke AG (NOK), today's Axpo AG , and the electricity company of the city of Zurich (EWZ). The corporation took over the concession granted on January 20, 1918 to use the hydropower of the Wägitaler Aa and the Trebsenbach from the electricity works of the canton of Zurich. This concession had a term of 80 years and expired in 1998, but was renewed.
investment
The upper stage has a catchment area of 42.7 km², which feeds the Wägitalersee . The water of the Wägitalersee is led through a pressure tunnel to the water lock and apparatus house above Rempen and from there in two above-ground pressure lines to the engine house in Rempen. The net gradient of the upper step is between 203 and 260 meters. The water flows from the engine house in Rempen into the Rempen basin, which originally had a usable volume of 360,000 m³ (today's usable volume is 285,000 m³). The Rempen Basin itself has an additional catchment area of 40 km² and serves as a compensation basin and as a reservoir for pumping operations. The lower step leads from the Rempen basin in a pressure tunnel to the water lock and apparatus house near Isenburg and from two underground pressure lines to the Siebnen engine house . The net gradient of the lower level is between 176 and 197 meters.
architecture
Headquarters Rempen
The structure is an iron high-rise, walled with sand-lime brick, with a rectangular floor plan and a hipped roof. The plans for the building come from the architects Müller & Freitag.
The Rempen headquarters was expanded in 1958. The facade was renovated between 1969 and 1972, the blue paintwork and the painted frieze attached by Bodmer and Rubli, from a sequence of tondo and five channel-like columns, were removed from the roof soffit in 1970.
Head office and switch house in Siebnen
The two concrete buildings were built according to plans by the brothers Adolf and Heinrich Bräm. The switch house is longer than the control center. This shorter building, which stands parallel to Wägitaler Aa, has a staircase designed as a front tower with the main portal. Above this portal are the two shell limestone sculptures that personify the engineer as creator and the Aa taken into the service of man. These two sculptures were created by Otto Kappeler.
Technical
Schräh dam
The Schräh dam is designed as a gravity dam . Of the total height of 111 m, 66 m are visible above the valley floor. The crown is 150 m long and 4 m wide.
The maximum stowage altitude 900 m above sea level. M. takes into account one meter of safety margin, which is required in the event of a landslide or flood. It took two years to fill the Wägitalersee, which is why the damming began while the dam was being built. The reservoir is used as a one-year storage facility and, for geological, scenic and operational reasons, is only allowed to reach the minimum reservoir level of 880 m above sea level. M. be lowered. The highest sea level in the annual cycle is reached in autumn. Most of the water stored in the lake is used to generate electricity in winter. The deepest lake level is therefore reached in spring before the snow melts.
On the left side there is the flood relief with three gate panels with a total discharge capacity of 105 m³ / s.
In order to guarantee flood security, a bottom outlet was subsequently created on the left side. The two closing elements mounted one behind the other have a capacity of 45 m³ / s. For the construction, a bell was attached by divers on the water side and the tunnel was drilled through the dam with a tunnel boring machine. In order to carry out the diving work, the lake was lowered to the minimum storage level.
The bottom outlet with three closing organs in a row, which was built in 1924 when the dam was built, was taken out of service in the late 1990s and poured with concrete.
Headquarters Rempen
During the initial installation, four vertical-axis Francis turbines , each with 19,000–20,000 hp, were installed on the turbine shaft at 500 revolutions per minute. Each turbine has its own three-phase generator with an output voltage of 8800 volts and an output of 16,500 kVA. The turbines at the Rempen headquarters were able to use up to 30 m³ / s of water. Each turbine had a turbine governor with a centrifugal governor and a small Pelton turbine . This auxiliary turbine was needed to supply the nozzle with oil pressure.
The four centrifugal pumps in the Rempen headquarters, with a line of around 5000 HP, are able to convey 1.25 m³ / s up to a maximum of 260 meters. This is sufficient to promote almost the entire summer runoff of the area near Rempen into the Wägitalersee.
Two machinists were present around the clock to operate the Rempen headquarters. When starting and stopping the machine groups, these had to work through a defined sequence by hand. Incandescent lamps were used for communication between the mechanic on the turbine floor and the electrical switch attendant on the balcony-like walkway on the first floor. So the other machinist knew when to take the next step in the sequence.
The power is transmitted via a 50 kV line with four circuits from the Siebnen switchgear building.
In 1972 the Rempen headquarters building was renovated. A new command room with an adjoining relay room replaced the electrical control point on the balcony-like walkway, as well as the on-site control points on the machine groups. The turbines, generators and pump groups could now be centrally monitored and automatically operated by a machine operator. The individual machine transformers were replaced by two transformers 50/9 kV (NOK) and 150/9 kV (EWZ). The machine groups were connected to the transformers by two busbars.
The four storage pump motors were replaced by new 9200 volt three-phase synchronous machines from the Oerlikon machine factory (Zurich). At a nominal speed of 750 revolutions per minute, an output of 4400 kW can be delivered to the pump. The cooling is ensured by a water-air cooler.
The turbine regulators were replaced by oil pressure regulators with servo motors. A centrifugal pendulum kept the speed constant. An oil hydraulic system was used to open the diffuser and water pressure from the pressure line to close it.
In 1996 the pole coils of the four generators were replaced because the insulation of the windings, which were over 70 years old at the time, was insufficient. The costs amounted to around CHF 650,000 per generator.
Rempen dam
In 1981 the Rempen dam was rebuilt. Two bottom outlets with a flow rate of approx. 90 m³ / s each are installed as closing organs. Four suction lifter flood reliefs and an automatic overflow flap are installed under the top of the dam . On the right side of the dam is the inlet with a throttle valve to the pressure tunnel of the central Siebnen.
Central Siebnen
During the initial installation, four vertical-axis Francis turbines, each with 16,000 HP, were installed on the turbine shaft. The three-phase generators connected to it have an output of 16,500 kVA at an output voltage of 8800 volts. These turbines from the Siebnen headquarters were able to use a water volume of up to 32 m³ / s.
Siebnen switch house
Original equipment with four transformers 8.8 kV / 50 kV and three transformers 50 kV / 150 kV. This fed ten outgoing 50 kV and two outgoing 150 kV lines. There are also four 50 kV transmission lines from the Rempen headquarters.
construction
The construction management was split up. The engineer Felix Gugler - at the same time director of the NOK - was responsible for the structural part, the engineer W. Trün - at the same time director of the ewz - was responsible for the electro-mechanical part.
Participating companies
- Schräh dam: Hatt-Haller (Zurich), Ed. Züblin & Co (Zurich)
- Dam Rempen: Locher & Cie (Zurich)
- Upper pressure tunnel and water intake: Baumann & Stiefenhofer (Wädenswil)
- Lower pressure tunnel: Simonett & Cie (Zurich)
- Upper pressure line: substructure; Dr. G. Lücher (Aarau) riveted part; Sulzer Brothers (Winterthur) water-gas-expanded part; Mannesmannwerke (Düsseldorf) assembly; Sulzer brothers
- Lower pressure line: substructure; JJ Rüegg & Co (Zurich) Head; Sulzer brothers with Mannesmannwerke Düsseldorf, Escher Wyss & Cie and Wartmann, Vellette & Co Earthworks + assembly help; G. Spärry (Näffels)
- Maschinenhaus Rempen: Simonett & Co (Zurich)
- Machine house Siebnen and switch house: JJ Rüegg & Co
- Turbines: Escher Wyss & Co (Zurich)
- Generators (Rempen) and transformers (Rempen + Siebnen): Brown, Boveri & Cie. (To bathe)
- Generators (Siebnen): Maschinenfabrik Oerlikon (Zurich)
- High pressure centrifugal pumps (Rempen only): Sulzer brothers (Winterthur)
- Motors for high-pressure centrifugal pumps (Rempen only): Maschinenfabrik Oerlikon (Zurich)
literature
- Swiss Water Management Association and Association of Swiss Electricity Works (ed.): Guide through the Swiss water and electricity industry , Volume 2, 1949, pp. 706–711
- Albrecht Jörger: Die Kunstdenkmäler des Kanton Schwyz , Volume II New edition: Der Bezirk March , new edition, GSK, Bern / Wise, Basel 1989, pp. 171–172, 397–398, ISBN 3-909158-22-6 (= Die Art Monuments of Switzerland , Volume 82).
- Gustav Kruck: The Wäggital power plant. New year's paper published by the Natural Research Society in Zurich for the year 1925. Beer, Zurich 1925.
See also
Web links
- Description of the power plant on the EWZ website
- Description of the power plant on rittmeyer.com
- Hydropower on the AXPO website (see Axpo hydropower plants (PDF) )
- AG Kraftwerk Wägital ( Memento from June 29, 2012 in the Internet Archive )
- Schräh dam. In: Structurae
- Swiss Dam Committee - characteristics of the dam (search under "Schräh")
Individual evidence
- ↑ KdKS page 172