摘要 |
There is disclosed a method of using an umbilical (3) between a surface location (1) and an underwater location of an underwater fluid extraction well system, the umbilical carrying an electrical power conductor and having been compromised by the ingress of water. Electrical power from a source (2) at the surface location at a first frequency is converted to electrical power at a second frequency, lower than the first frequency, or to DC electrical power; said electrical power at the second frequency or said DC electrical power is transmitted to the underwater location via the conductor; and at the underwater location, said electrical power at the second frequency or said DC electrical power is converted to electrical power at a frequency used by underwater equipment of the well system. |