Claims
- 1. A subsea pipeline power transmission system comprising a pipeline, an electrical power supply connected to the pipeline at a first location, and at least one connector provided on the pipeline at a second location for connection of a load to the pipeline to allow the load to receive electrical power from the power supply via the pipeline wherein the pipeline has a plurality of cathodic protection anodes, each of which is electrically connected via a respective impedance element to the pipeline.
- 2. A power transmission system according to claim 1 in which each impedance element is arranged to give a high impedance to time varying signals within at least one selected range of frequencies and a low impedance to signals outside the selected range.
- 3. A power transmission system according to claim 2 in which each impedance element is arranged so that the real part of the impedance is substantially zero, such that there is no significant attenuation of dc components of signals passing through the impedance means.
- 4. A power transmission system according to claim 2 in which the impedance element comprises an inductance element.
- 5. A power transmission system according to claim 2 in which the impedance element comprises a filter.
- 6. A method of subsea pipeline power transmission along a pipeline having a plurality of cathodic protection anodes comprising the steps of:applying electrical power to the pipeline at a first location; and electrically connecting a load to be supplied to the pipeline at a second location; wherein each anode is electrically connected via a respective impedance element to the pipeline.
- 7. Apparatus for use in a subsea pipeline power transmission system comprising:an anode arrangement comprising, a cathode protection anode arranged for mounting on a pipeline and an impedance element having one terminal connected to the anode and another terminal arranged for connection to said pipeline; and an electrical power supply arranged for electrical connection to a pipeline.
- 8. An anode arrangement for use in a subsea pipeline power transmission system, the arrangement comprising, a cathode protection anode arranged for mounting on a pipeline and an impedance element having one terminal connected to the anode and another terminal arranged for connection to said pipeline.
- 9. An anode arrangement according to claim 8 including terminals allowing the connection of a load across the impedance element.
Priority Claims (2)
Number |
Date |
Country |
Kind |
9916410 |
Jul 1999 |
GB |
|
0100104 |
Jan 2001 |
GB |
|
CROSS REFERENCE TO RELATED APPLICATIONS
This application is a division of application Ser. No. 10/032,471 filed Jan. 2, 2002, now U.S. Pat. No. 6,788,075, which is a continuation-in-part of International Patent Application No. PCT/GB00/02493, filed Jun. 23, 2000, claiming priority of Great Britain Patent Application No. 9916410.5, filed Jul. 13, 1999, and Great Britain Patent Application No. 0100104.9, filed Jan. 3, 2001.
US Referenced Citations (8)
Foreign Referenced Citations (2)
Number |
Date |
Country |
0 241 440 |
Oct 1987 |
EP |
2006953 |
Jan 1994 |
RU |
Continuation in Parts (1)
|
Number |
Date |
Country |
Parent |
PCT/GB00/02493 |
Jun 2000 |
US |
Child |
10/032471 |
|
US |