Kontek

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Converter station of the HVDC Kontek in Bentwisch
50 Hertz HVDC substation in Bentwisch

The high-voltage direct current transmission (HVDC) Kontek is a 400 kV, 170 km long, monopolar direct current cable for coupling the German power grid and the power grid of the Danish island of Zealand . The name "Kontek" comes from " Continent " and the name of the Danish network operator Elkraft (today Energinet.dk ), who operates the electricity network on the Danish islands of Lolland , Falster and Zealand and was abbreviated to "ek". The transmission system operator 50Hertz is responsible on the German side . The HVDC Kontek can transmit a maximum of 600 MW and has been in operation since 1996.

What is remarkable about the HVDC Kontek is that, in contrast to similar systems such as the HVDC Baltic Cable and the HVDC Kontiskan , all 119 kilometers of land sections on Falster, Zealand and in Germany were not designed as overhead lines but as underground cables . This unusual measure, which has made the construction of the Kontek line connection not insignificantly more expensive, has no technical reasons, but was rather carried out in the interest of timely completion, as approval procedures for overhead lines can be very tedious nowadays.

The HGÜ Kontek has been supplemented by the Combined Grid Solution since 2019 . It is routed through the two 150 kV three-phase cables that have existed since the 2010s via the offshore wind farms EnBW Baltic 1 and EnBW Baltic 2 .

The Kontek submarine cable between Germany and Denmark was renewed in the 2010s by a new cable in a slightly further west location, the old cable was removed. In the 2020s, the renewal of the cables in the land sections is due.

Guide the cable

The cable of the HVDC Kontek begins in the south of Bentwisch situated converter station ( 54 ° 6 '2 "  N , 12 ° 12' 53"  O ). It runs together with the cable to that in the Baltic Sea located cathode , which is designed as a copper ring, to a length of 13 kilometers over land and reaches Markgrafenheide the Baltic Sea. This is where the 43 kilometer long submarine cable section to the island of Falster begins . Shortly behind the coastline, the Kontek cable leading to the cathode branches off in an easterly direction to the cathode located east of the submarine cable route.

In the Baltic Sea between Germany and Falster, the high-voltage cable of the HVDC Kontek also crosses the cable of the HVDC Baltic Cable. For the realization of this crossing, an approx. 50 centimeter high ramp was built over the "Baltic Cable" on the bottom of the Baltic Sea, on which the cable of the HVDC Kontek lies. At Gedser , the Kontek submarine cable reaches the island of Falster, which it crosses over a length of 50 kilometers as an underground cable. This is followed by another 7 km long submarine cable section to cross the sea between Falster and Seeland. This section is followed by a 53-kilometer section of land cable on Zealand, which ends at the Bjæverskov Sogn converter station . In contrast to the cable section at Rostock, the electrode cable does not run parallel here. Rather, this runs from Bjæverskov in a south-easterly direction to the anode located in front of the south-easternmost end of Zealand , which is designed as a titanium mesh laid off the coast of Zealand .

Circuit of the harmonic filter on the AC voltage side
Impedance curve of the harmonic filter for suppressing the 11th, 13th, 23rd and 25th harmonic

Technical

The first generation of Kontek high-voltage cables was designed as a paper-insulated oil cable with two copper conductors with a cross-section of 800 mm² that were permanently connected in parallel. On the land sections, to better monitor the oil in the cable, it was divided into approximately 8 km long sections, which are separated from each other by oil-impermeable locking sleeves. In the vicinity of these locking sleeves - somewhat separated from the cable route - there are unoccupied automatic stations for monitoring the oil pressure, the oil temperature and other operating parameters of the cable.

In Germany there are three such cable monitoring stations north of Bentwisch ( 54 ° 7 ′ 47 ″  N , 12 ° 12 ′ 6 ″  E ), south of Stuthof ( 54 ° 9 ′ 41 ″  N , 12 ° 10 ′ 26 ″  E ) and at Markgrafenheide at the end of the submarine cable section ( 54 ° 12 ′ 13 ″  N , 12 ° 9 ′ 7 ″  E ). In contrast to the land sections of the Kontek, the 45 kilometer long submarine cable section through the Baltic Sea between Germany and Denmark was carried out without locking sleeves for practical reasons. Commercially available plastic-insulated 17 kV cables are used as electrode cables from Kontek - both on the German and on the Danish side.

The converter station in Bjæverskov Sogn ( 55 ° 26 ′ 57 ″  N , 12 ° 0 ′ 4 ″  E ) was attached to an existing substation for 380/110 kV. In contrast, the converter station in Bentwisch is a new building on the " green field ", although the 220/110 kV substation Bentwisch, which dates back to the GDR era, is only one kilometer north . However, the HVDC “Kontek” system was expanded in 2002 by a 380/110 kV substation and connected to it via a 110 kV line designed as an overhead line.

Web links

Commons : Kontek  - collection of pictures, videos and audio files

Individual evidence

  1. 400 kV network connection KONTEK 50hertz.com, accessed on July 4, 2020