A cable fault is preventing transmission of
power from the Anholt
offshore wind farm to the onshore
grid, The fault meant that the islanders lost power for 31 minutes before
the emergency supply was up and running, and also that it is not possible
to transmit the power being generated by the wind turbines to shore.
It is yet too early to say anything about the cause of the fault, but over
the weekend Energinet.dk and its partners located the fault, which is affecting
the sea cable close to the offshore transformer platform connecting the
wind turbines and the sea cable.
There is nothing to suggest that the fault has been caused by a ship or
Two vessels are currently preparing to start doing the repairs. One vessel
will carry out the water-jetting procedure to expose the cable which lies
protected in the seabed. The other vessel will raise the cable to the surface
and make the necessary repairs.
- Repairing sea cables is far more difficult and also far more time-consuming
than repairing cables on land. We expect the repairs to take approx. three
weeks. However, as we need two periods of reasonably calm weather lasting
several days, it may be more than three weeks before the wind farm will
again be transmitting power to shore, says Per Hylle, Head of Department
– Maintenance Jutland, Energinet.dk.
cable was also
hit by a fault last year. On 30 September, the onshore part of the power
cable short-circuited. This resulted in the cable being out of operation
for seven days.
Energinet.dk has therefore had to pay compensation in the amount of DKK
9,167,090.95 to DONG Energy, the owner of the wind turbines, for loss of
profit during the seven-day period. The compensatory amount was based on
wind data and market prices; in other words, what the wind turbines would
have generated and earned.
The part of the cable which short-circuited has since been examined by
a laboratory. Part of the cable was destroyed by the high temperatures
produced, and it is therefore not possible to say exactly what caused the
fault. However, it may have been caused by a fault in the insulation of
the cable – either during the laying of the cable or during production
of the cable.
The bill for identifying the fault and replacing the damaged part of the
cable came to approx. DKK 1.5 million.
The sea cable was supplied by NKT Cables, while the land cable was supplied
by Silec Cable.
Back in February 2013 some of the cable was unable to be buried to the
depth needed, therefore rock dumping was used.
This is not the first time that the project has been troubled
by cable failure. Back
in Ocober it was announced that earlier cable problems had just been repaired.
This was due to a failure that occurred Thursday 30 September at
8.35. This was due to a short circuit found on the part of the cable buried
a few kilometres west of the town Grenå. The failure was in a relatively
small, limited part of the cable, but in order to make the most appropriate
repair, a larger piece of the cable, approx. 20 metres, had to be cleared,
cut off and replaced by a new piece of cable.
The reason beyond those given
then were not fully understood as there was a need for further investigations
by the supplier in order to precisely clarify what caused the failure.
Costs for that repair were not given however it was understood that
Dong Energy were compensated for losses to the tune