A subsea variable speed drive apparatus comprising a pressure resistant container (90) comprising a curved wall section having a curved, internal surface (90a); and a variable speed drive comprising at least one power electronics module (50) arranged inside the container and held at a predetermined ambient pressure. The at least one power electronics module is mounted on a heatsink (40) which is mounted on the internal surface, the heatsink comprising a curved surface (40b) contacting the internal surface and having a radius of curvature corresponding to the radius of curvature of the internal surface. A subsea hydrocarbon fluid pumping system comprising such subsea variable speed drive apparatuses and a related method are also disclosed.

A pressure compensated subsea arrangement for housing of electric components. The arrangement includes a pressure compensated housing. The pressure compensated housing is filled with a dielectric liquid. The arrangement includes at least one electric component. The at least one electric component is provided inside the pressure compensated housing. The dielectric liquid is a hydrocarbon dielectric liquid including isoparaffin. There is also provided a method of manufacturing such an arrangement.

Systems (100) and methods (1500) for using a pressure vessel. The methods comprise: obtaining the pressure vessel comprising a shell and an insert having an interference fit with the shell whereby the insert is locked in place within the shell via interfacial pressure; inserting at least one electronic component in a first hollow cavity formed in the insert; mechanically supporting the at least one electronic component using a structural feature of the insert; and transferring heat from the electronic component to an external environment via a heat transfer path that comprises a full surface area of the insert's outer surface abutting the shell's inner surface.

An arrangement for cooling components of a subsea electric system including a tank filled with a dielectric fluid. The tank includes first and second sections. The arrangement includes one first electric component within the first section, and one second electric component within the second section. The arrangement includes a first heat exchanger located outside the tank and in fluid contact with the tank, and arranged during operation to be in thermal contact with sea water. The arrangement includes a pump arranged to force a flow of dielectric fluid through the first heat exchanger. Flow of dielectric fluid in the tank is by both natural and forced convection generated by the pump. The first electric component generates more heat than the second electric component. Within the first section the share of the flow by natural convection is greater than within the second section.

A power converter includes an outer housing formed of dielectric material and including a low voltage compartment and a high voltage compartment is disclosed. The power converter also includes a low voltage DC-to-AC converter disposed in the low voltage compartment, a first coil in the low voltage compartment, a first conductive shield element lining an outer wall of the low voltage compartment, the first conductive shield element being electrically coupled to an electrical input of the DC-to-AC converter and a second conductive shield element lining an outer wall of the high voltage compartment.

A subsea converter includes an outer housing, configured to be in contact with the subsea water when the converter is installed subsea, and an inner housing provided inside the outer housing. The inner housing is fluid tight sealed against the outer housing. Further, at least one first electric component is located inside the outer housing but outside the inner housing. The outer housing is filled with a first dielectric fluid and at least one capacitor is located inside the inner housing. Finally, the inner housing is filled with a second dielectric fluid, the second dielectric fluid having a lower moisture content than the first dielectric fluid.

A canister system having a cylindrical housing and a modular electronic rack system disposed within the cylindrical housing. The modular electronic rack system includes a thermal contact member that is in at least selective physical contact with an interior surface of the cylindrical housing to permit conductive heat transfer there through. An input/output device extends along at least a portion of the modular electronic rack system and includes a power input and a signal output electrically coupled thereto. A plurality of electronic slots disposed at a position generally along the modular electronic rack system is provided.

A power converter includes an outer housing formed of dielectric material and including a low voltage compartment and a high voltage compartment is disclosed. The power converter also includes a low voltage DC-to-AC converter disposed in the low voltage compartment, a first coil in the low voltage compartment, a first conductive shield element lining an outer wall of the low voltage compartment, the first conductive shield element being electrically coupled to an electrical input of the DC-to-AC converter and a second conductive shield element lining an outer wall of the high voltage compartment.

A subsea arrangement including a main enclosure having a main enclosure volume; at least one main pressure compensator having a variable compensation volume in fluid communication with the main enclosure volume and configured to compensate volume variations of an internal fluid in the main enclosure volume; and at least one pressure sensor arranged to measure a pressure of the internal fluid. A method for detecting a malfunction of a subsea arrangement including a main enclosure having a main enclosure volume and at least one main pressure compensator is also provided.

Provided is a deionized-water cooling system having a main circuit for cooling electrical equipment. The system includes a deionizer circuit including (i) a deionizer for producing deionized water and (ii) a throttle and a main pumping system configured for circulating (i) the deionized water within the main circuit at a first flow rate and (ii) the water flow within the deionizer at a second flow rate. The circulating occurring when the electrical equipment is operating. The electrical equipment is configured for receiving power from a primary power source. Also included is a secondary pumping system configured for (i) receiving power from a secondary power source, (ii) circulating the deionized water within the main circuit, and (iii) circulating the water flow within the deionizer at the second flow rate via the throttle when the electrical equipment is inoperable.