Kontek repairs 2008

Client: Energinet.dk

Kontek is the name of the communications link between Gedser in Denmark and Rostock in Germany, comprising of a 400 KV high voltage paper isolated mass-impregnated cable. The cable is surrounded by a paper insulation layer and filled with oil to act as an insulating layer between the inner live wires and the outer layer of sea armouring. The oil also keeps the cable cooled, and the pressure of the oils prevents sea water from seeping in and causing damage to the underwater cable. The cable technology is well established and very stable.

In January 2008 it was noted that there was one or more leaks from the Kontek cable as the oil pressure fell in both Denmark and Germany, but it was not known which part of the 42 km-long cable was damaged. On an earlier occasion when the Kontek sprang a leak, JD-Contractor A/S was able to quickly localise the leak and place an oil collector over the cable to limit the oil spill until our cable ship could arrive and repair the damage.

Already in February, M/S Honte and C/S Cable One were sent to the Baltic Sea and located a leak in joint 3 (3 km south of Gedser). To protect the environment, M/S Honte placed an oil collector over the leak to collect oil from the leaking cable. The oil collector is a part of the special equipment, which Contractor A/S uses in connection with oil spillages from instillations and shipwrecks.

Oil from the leaking cable is collected in the oil collector

Repairs:

1. Joint 3: At Gedser approx. 80 m cable was exchanged including joint 3, and 2 new connections were established: joint 3a and 3b.

06 March 2008 –29 March 2008.

Position: Joint 3a: 54 32 291 – 11 58 427
Position: Joint 3b: 54 32 262 – 11 58 435

In all 80m of cable was exchanged.

2. Joint 38: At Rostock 1 joint repaired

30 March 2008 – 06 April 2008

Position: 54 13 045 – 12 06 615

3. Repair between joint 36 and joint 37A

07 April 2008 –17 April 2008

Damaged position: 54 13 784 – 12 06 333

In order to do the repairs at joint 38 and at the fault between joints 36 and 37a, the cable was jetted free and under run from the seabed from 50m south of joint 38 up to 50 m north of the damaged site between 36 and 37a. Altogether 1518m of the cable was jetted free and under run from the seabed. This was a protective measure and meant the cable did not have to be spliced or further extended.

The time taken for the repairs was extended due to bad weather conditions, though time was saved as the three repairs could take place sequentially.