Three-phase transmission Lauffen – Frankfurt
The three-phase transmission Lauffen – Frankfurt was the first transmission of electrical energy with high-voltage three-phase current . It took place on Tuesday, August 25, 1891 at 12 noon on the occasion of the International Electrotechnical Exhibition in Frankfurt am Main and was presented there as the Lauffen – Frankfurt power transmission . The first test run had already been successful the day before.
construction
An essential innovation of the transmission line was that the three-phase alternating current generated by the generator with a very low star voltage of 55 V was stepped up to 15 kV , later experimentally up to 25 kV, and over 176 km by means of a three-phase alternating current transformer , which was located next to the generator long overhead line was forwarded to Frankfurt am Main. In Frankfurt, the voltage was converted to 100 V with a further three-phase transformer and thus served to supply more than 1000 light bulbs at the electrotechnical exhibition at the time . In addition, a 74 kW (100 PS) three-phase synchronous motor , which was designed for 65 V, was driven. This in turn drove a pump for an artificial waterfall on the exhibition grounds.
The entire system was designed and built by AEG and Maschinenfabrik Oerlikon under the direction of Oskar von Miller and Michail Ossipowitsch Doliwo-Dobrowolski . The transformer system, the generator and the oil insulators were made by Charles Brown jun. developed. Margarethenhütte in Großdubrau took over the production of the isolators .
generator
The generator of this system, designed as a three-phase synchronous machine with 221 kW (300 PS), was located in the cement works of Lauffen am Neckar , was designed as an internal pole machine and was driven by water power. Due to the low generator voltage in the stator of only 55 V, the current in the stator was up to 1400 A at full load , which necessitated the use of solid copper bars with a diameter of almost 30 mm and thermally stable insulation with asbestos pipes. The rotating rotor was equipped as a claw pole wheel with 32 comb-like interlocking pole pieces. The excitation current supplied by accumulators was fed to the rotor via two copper wire cords, which were attached to contact rings in the form of rope pulleys in the front area of the generator towards the axis. The generator was designed for 150 revolutions per minute and had 16 pole triples on the stator. The resulting frequency of the three-phase alternating current was 40 Hz, the three-phase transformers , which were already oil-cooled , were two 100-kVA transformers from AEG and one 150-kVA transformer from Maschinenfabrik Oerlikon, which also built the synchronous machine.
Route
The overhead line mainly followed railway lines. From the Lauffen power station, the line first crossed the Neckar from the island in order to meet the Franconian railway opposite . From there she followed the track to Jagstfeld and switched to the Neckar Valley Railway . From Eberbach she accompanied the Odenwaldbahn to Hanau and from there the Frankfurt-Hanauer Eisenbahn to the exhibition area 1000 meters in front of the new Frankfurt main station. The five tunnels had to be bypassed more widely, which required a total of around seven kilometers longer than the rail route. On Baden territory, the masts had to be fenced in as a security measure.
The three-phase overhead line required about 3,000 masts, 9,000 oil insulators and 60 tons of copper wire with a 4 mm diameter. The transmission loss was - for the conditions at the time - only a sensational 25%. In later operation with 25 kV, the loss could even be reduced to 4%.
After the exhibition, the generator was used to power Heilbronn , which was the first city in the world to receive a three-phase power supply . The name of the local energy supplier ( Zementwerk Lauffen - Elektrizitätswerk Heilbronn AG ) still reminds of this event today . The overhead line between Heilbronn and Frankfurt remained in the possession of the Deutsche Reichspost and was henceforth only used for telegraphy , while the remaining line continued to supply Heilbronn. After 50 years, the power plant was replaced by a stronger facility upstream and a little later gave way to canal construction. The original generator has been in the Deutsches Museum in Munich since then .
Historical meaning
- The long and passionate debate among the world's electricity pioneers as to whether energy should be transmitted with direct current or alternating current was unequivocally decided until the invention of more advanced direct current technologies .
- The choice of location for factories was no longer dependent on water as a source of energy. This caused industry to migrate from remote locations and to concentrate in metropolitan areas - with far-reaching social consequences that continue to the present day.
In January 1892 , Heilbronn , located near Lauffen, was the first city in the world to take up regular remote electricity supply by continuing to use the Lauffener systems created for transmission to Frankfurt am Main. However, almost 50 years passed before the last town in Germany was converted to alternating current or even connected to electricity.
The three-phase motor in Frankfurt with a coupled pump behind the artificial waterfall.
Sketch of the oil insulators that were used at that time.
First conceptual circuit diagram where 8,500 V is still mentioned
Rear view of the engine in Frankfurt. The switchboards on the walls
See also
literature
- Modern energy for a new era - the three-phase transmission Lauffen a. N. - Frankfurt a. M. 1891 . In: Horst A. Wessel (Hrsg.): History of electrical engineering . tape 11 . vde-Verlag, Berlin 1991, ISBN 978-3-8007-1813-9 .
- The electric power transmission . In: The Gazebo . Issue 40, 1891, pp. 682 ( full text [ Wikisource ]).
Web links
- Three-phase transmission generator. German museum
- Report on the electrification history of Frankfurt (PDF; 3.7 MB)
Individual evidence
- ^ History of the Margarethenhütte at www.museum-mhuette.de
- ↑ Christhard Schrenk , Hubert Weckbach , Susanne Schlösser: From Helibrunna to Heilbronn. A city history (= publications of the archive of the city of Heilbronn . Volume 36 ). Theiss, Stuttgart 1998, ISBN 3-8062-1333-X , p. 146 f .