A subsea power system

Publishing Venue

The IP.com Prior Art Database

Abstract

A subsea power system comprises a subsea transformer (1) with a primary winding (2) thereof connected to a high or medium alternating voltage network, a secondary winding (4) thereof connected to a first power distribution system (6) and a further winding (5) thereof 5 connected to a further power distribution system (7) in parallel with the first power distribution system. At least two converters (11, 12) have an input to a rectifier (13, 14) thereof connected to said first as well as said further power distribution system. The output of the converters (13, 14) provides an AC or a DC power to at least one consumer (19) of electric 10 power.

278624A

A subsea power system

TECHNICAL FIELD OF THE INVENTION

The present invention relates to a subsea power system comprising at

least one subsea transformer configured to have a primary winding thereof connected to a high or medium alternating voltage network and at least one converter comprising a rectifier connected to a secondary winding of said transformer and an inverter connected to the output of the rectifier so as to provide an AC power to at least one consumer of

electric power.

Said high or medium voltage network may be of any conceivable type suitable to feed a said subsea power system, and it may as an example be connected to said transformer through a subsea high or medium

voltage cable from a power station onshore or from an existing platform located at sea in an offshore oil and/or gas field.

It may by way of example be mentioned that a said consumer of electric power may belong to different types of subsea electric motors, such as

for driving impellers of subsea pumps.

BACKGROUND ART

Known such subsea power systems do normally cover large areas in

the form of a subsea field comprising an amount of wells or installations and have for that sake a plurality of said converters distributed over that area for providing said consumers with electric power. These systems have for each said converter a said subsea transformer connected to the rectifier of the converter for carrying out a 6-pulse, 12-

pulse, or >12-pulse rectification for providing a direct voltage to the inverter or inverters of the converter.

There is of course an ongoing attempt to improve such subsea power systems not at least for saving costs for the construction and operation

thereof.

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278624A

SUMMARY OF THE INVENTION

The object of the present invention is to provide a subsea power system of the type defined in the introduction being improved in at least some aspect with respect to such subsea power systems already known.

This object is according to the invention obtained by providing such a subsea power system with the features listed in the characterizing part of appended patent claim 1.

By arranging two said power distribution systems in parallel and providing said subsea transformer with at least one further winding this transformer may be connected to said systems through a separate output winding thereof and deliver an alternating voltage with a phase shift, so that only one subsea transformer will be needed for such a

subsea power system having a plurality of converters then connected to said two power distribution systems along the extension thereof. This means a possibility to a considerable cost saving, especially in the case of feeding subsea fields covering large areas by a said subsea power system then having a rather high number of said converters.

According to an embodiment of the invention said secondary and further winding of the transformer are configured to deliver alternating voltages with a mut...