| Fenno–Skan | |
|---|---|
| Location | |
| Country | Finland, Sweden |
| Coordinates | |
| From | Rauma, Finland |
| Passes through | Gulf of Bothnia |
| To | Dannebo, Sweden |
| Ownership information | |
| Operator | Fingrid, Svenska Kraftnät |
| Construction information | |
| Manufacturer of conductor/cable | ABB |
| Expected | 2011 (2nd cable) |
| Commissioned | 1989 |
| Technical information | |
| Type | subsea cable |
| Type of current | HVDC |
| Total length | 233 km (145 mi) |
| Power rating | 550 MW |
| AC Voltage | 400 kV |
| DC Voltage | 400 kV (500 kV) |
| Number of poles | 2 |
Fenno–Skan is the designation of the high voltage direct current transmission between Dannebo in Sweden and Rauma in Finland.
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Fenno–Skan was inaugurated in 1989.[1][2] Taken into commercial operation in November 1989, Fenno–Skan was the longest submarine power cable in the world. It was also the first HVDC cable with 400 kV voltage and a rated power of 500 MW.[3]
The Fenno–Skan is a monopolar system with a maximum transmission rate of 550 megawatts (MW) at a voltage of 400 kV. It would be converted to become a bipole.[1] The cable was manufactured by ABB.[1][2]
The total length of Fenno–Skan is 233 kilometres (145 mi), of which 200 kilometres (120 mi) is a submarine cable on the bottom of the Gulf of Bothnia. At the Swedish end the cable directly enters the Dannebo static inverter plant near the Forsmark nuclear power station about 1 kilometre (0.62 mi) from the coast at 60°24'16"N 18°8'4"E. However, the electrode line from the static inverter plant to the ground electrode situated at 60°35'51"N 17°57'46"E is built as overhead line. It is a line with two conductors on wooden poles, which runs partly on its course past another powerline.
There is a 33 kilometres (21 mi) long overhead line section from the coast in Finland at 61°4'37" N, 21°18'18" E to the static inverter station in Rauma, situated at 61°9′7″N 21°37′32″E.[1]
The ground electrode in Finland is situated near Rantala. From there an overhead electrode line on wooden poles runs first in Northeast, than in Northern direction until Ruokalho, where it meets the overhead line with two high voltage conductors. From Ruokalho to Rauma static inverter plant the electrode line is fixed on a small crossbar above the high voltage conductors of Fenno–Skan and serves as ground conductor. In opposite to a normal ground conductor it is mounted on insulators equipped with surge arrestors.
Fenno–Skan is operated by the Finnish and Swedish transmission system operators Fingrid and Svenska Kraftnät.[2]
There is a plan to add the second cable to the existing HVDC connection. A new 800 MW, 500 kV subsea transmission connection will be laid in 2011 by the cable laying ship SC Skagerrak, and it is costs €150 million. The cable will be manufactured by Nexans Norwegian plant in Halden.[4] Two converter stations would be supplied by ABB.[2] Compare with Fenno–Skan 1, the Swedish converter station would be located in Finnböle. The Fenno–Skan 2 cable would be connected to the converter station by a 70 kilometres (43 mi) long DC overhead line. The pylons of this line are "classic HVDC pylons" with a single crossbar carrying two conductors, which consist of a bundle of three ropes, on 5.5 metres long insulators. Fenno–Skan 2 crosses the traction current power line Tierp-Gävle and the parallel-running three phase 220 kV AC powerline Mehedeby-Gävle west of Mehedeby approximately at . This is the only crossing of an HVDC powerline and a single-phase AC powerline in the world and the only place where all kinds of electric transmission systems, three phase AC powerline, single phase AC powerline and HVDC come close together .[1]
| Site | Coordinates |
|---|---|
| Finnbole HVDC Static Inverter | |
| Dannebo HVDC Static Inverter | |
| Hallen Electrode Line Terminal (Sweden) | |
| Tiirojärvi Cable Terminal (Finland) | |
| Rantala Electrode Line Terminal (Finland) | |
| Ruokalho Electrode Line Branch (Finland) | |
| Rauma HVDC Static Inverter Plant |