Patent Application
20160126032
BACKGROUND
Embodiments of the disclosure relate generally to a switch apparatus and a system having the same, and more particularly to a switch apparatus for high pressure environments.
As oil and gas fields in shallow waters diminish, producers are tapping offshore fields in deeper waters with oil and gas production installations that operate far below the surface of the sea. The oil and gas production installations operate not only far below the surface of the sea but also far away from the shore. The oil and gas production installations use power transmission and distribution systems for delivery of electric power to subsea locations. A subsea switch is one of the key subcomponents for the power transmission and distribution system. Current subsea switches of the power transmission and distribution systems are completely assembled in bar vessels. As the sea depth increase, the bar vessels gradually become heavy and unwieldy modules to against subsea high pressure.
It is desirable to provide a solution to address at least one of the above-mentioned problems.
A switch apparatus is provided. The switch apparatus includes a switch main body, a switch actuator, a housing and at least one pressure compensator. The switch main body includes multiple of contacts. The switch actuator is coupled with the switch main body and configured to trigger movement of the contacts. The housing accommodates the switch main body and the switch actuator and is filled with insulation fluid. The pressure compensator is in fluid communication with the housing and has a variable volume to regulate pressure inside the housing equal to external pressure surrounding the housing.
A system is provided. The system includes a main apparatus, a switch apparatus, and a circuit breaking device. The main apparatus is for use in an underwater environment. The switch apparatus is coupled to the main apparatus and exposed to the underwater environment and includes a switch main body, a switch actuator, a housing and at least one pressure compensator. The switch main body includes multiple of contacts. The switch actuator is coupled with the switch main body and configured to trigger movement of the contacts. The housing accommodates the switch main body and the switch actuator and is filled with insulation fluid. The pressure compensator is in fluid communication with the housing and has a variable volume to regulate pressure inside the housing equal to external pressure surrounding the housing. The circuit breaking device is coupled with the switch apparatus for breaking a circuit.
These and other features and aspects of embodiments of the present invention will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings, wherein:
Unless defined otherwise, technical and scientific terms used herein have the same meaning as is commonly understood by one of ordinary skill in the art to which this invention belongs. The terms “a” and “an” do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced items, and terms such as “front”, “back”, “bottom”, and/or “top”, unless otherwise noted, are merely used for convenience of description, and are not limited to any one position or spatial orientation. Moreover, the terms “coupled” and “connected” are not intended to distinguish between a direct or indirect coupling/connection between two components. Rather, such components may be directly or indirectly coupled/connected unless otherwise indicated.
The main apparatus 12 is for use in an underwater environment, such as a subsea environment, and includes a power conversion system 22 in this embodiment. The power conversion system 22 is operative to convert power from the power source 18 for the operating system 20. In one embodiment, the power source 18, for example an AC generator, supplies high voltage AC power, and the power conversion system 22 converts the high voltage AC power to high voltage DC power. In another embodiment, the power source 18 supplies high voltage DC power, and the power conversion system 22 converts the high voltage DC power to high voltage AC power. The high voltage is at least 5 kV and current is above 100 A, for example. In another embodiment, the power source 18 supplies one type of DC power, and the power conversion system 22 converts the one type of DC power to another type of DC power. In another embodiment, the power source 18 supplies one type of AC power, and the power conversion system 22 converts the one type of AC power to another type of AC power. The power conversion system 22 may include a converter or an inverter. In another embodiment, the main apparatus 12 may include one or more other systems/components (not shown) coupled with the power conversion system 22, such as rectifier.
The switch apparatus 14 is coupled to the main apparatus 12 and exposed to the underwater environment. In one embodiment, the switch apparatus 14 is located subsea. In this embodiment, the switch apparatus 14 is coupled in parallel to the power conversion system 22 and operative to bypass the power conversion system 22. In another embodiment, the switch apparatus 14 is coupled in series to the power conversion system 22 to isolate the power conversion system 22. In another embodiment, more than one switch apparatus 14 are employed to bypass or isolate the main apparatus 12. In another embodiment, more than one power conversion system 22 is employed. Even if one faulty power conversion system 22 is bypassed or isolated by the switch apparatus 14, other power conversion systems 22 still operate normally. The switch apparatus 14 is employed to promote protection for the system when the main apparatus 12 is faulty, such as open circuit fault. In one embodiment, the switch apparatus 14 is a DC switch apparatus having an operation voltage of at least 5 kV. The switch apparatus 14 is operating in a high voltage DC power system with at least 5 kV.
The circuit breaking device 16 is coupled with the switch apparatus 14 for breaking a circuit. In this embodiment, the circuit breaking device 16 is coupled with the power conversion system 22. For example, when a fault occurs at the main apparatus 12, the switch apparatus 14 bypasses the main apparatus 12, and the circuit breaking device 16 connected with the switch apparatus 14 may break the circuit to stop power from the power source 18 to the power conversion system 22 and the switch apparatus 14 so as to protect the system 10. In one embodiment, the circuit breaking device 16 includes one or more breaking circuits. In one embodiment, the circuit breaking device 16 is integrated in the power source 18. In this embodiment, the circuit breaking device 16 and the power source 18 are located topside. As used herein, the term “topside” means above the waterline 24. In some embodiments, the power source 18, the circuit breaking device 16, the power conversion system 22, the switch apparatus 14 and/or the operating system 20 are controlled by a controller (not shown).
The switch apparatus 14 may be used in other applications but not limited to the embodiment of
In the illustrated embodiment, the power conversion system 22 includes an inverter 26, a solid state switch S2, inductances L1-L4 and a capacitance C1. The inverter 26 and the capacitance C1 are coupled in parallel and the capacitance C1 serves as a bus filter. The inductances L1-L4 serve as cable parasitic inductances. The solid state switch S2 is coupled in parallel to the capacitance C1. The solid state switch S2 is open during normal operation of the inverter 26, and the solid state switch S2 is closed when a fault occurs at the inverter 26. The solid state switch S2 can be turned on more quickly than the switch S1, however power loss at the solid state switch S2 is much higher than the power loss at the switch S1. When the fault occurs, the switch S1 is closed after the solid state switch S2 is closed, and then the solid state switch S2 may be opened after the switch S1 is closed.
The housing 34 accommodates the switch main body 30 and the switch actuator 32 and is filled with insulation fluid 38. The housing 34 may be made of metal such as alloy steel, titanium alloy. In one embodiment, the housing 34 includes a cylindrical or spherical outer enclosure such that high intensity of pressure at some portions of the housing 34 is avoided. In another embodiment, the housing 34 may include any other smooth curved surface. The housing 34 is totally filled with the insulation fluid 38, and the switch main body 30 and the switch actuator 32 are totally immersed in the insulation fluid 38. The insulation fluid 38 provides a uncompressible feature, in such a way that voids inside the housing 34 are avoided to handle the subsea high pressure.
In this embodiment, the insulation fluid 38 is not pressurized when being injected into the housing 34. The pressure of the insulation fluid 38 inside the housing 34 is changed as the pressure of the external environment surrounding the housing 34. The pressure of the insulation fluid 38 is substantial same as the pressure of the external environment. For example, the pressure of the insulation fluid 38 is about 300 bar when the switch apparatus 14 is in 3 km deep sea and the pressure of the external environment is about 300 bar. Accordingly, the housing 34 with a thin wall can handle the high pressure due to the insulation fluid 38, so that weight and volume of the switch apparatus 14 are reduced a lot.
In one embodiment, a dielectric strength of the insulation fluid 38 is in the range of 1 kV/mm to /100 kVmm. In one embodiment, the insulation fluid 38 includes at least one of mineral oils, silicone oils, MIDEL oil, organic esters and synthetic oils, which have high breakdown strength and are provided after vacuuming and filtering. In another embodiment, the insulation fluid 38 may include any other types of dielectric oils, liquid or fluid with similar dielectric strengths. The insulation fluid 38 provides high voltage insulation medium.
In one embodiment, the switch main body 30 and the switch actuator 32 are pressure tolerant. The switch actuator 32 and the switch main body 30 include one or more pressure tolerant components (not shown) immerged in the insulation fluid 38. The components of the switch main body 30 and the switch actuator 32 do not have a void with air or vacuum therein, that is to say the void of the components are filled with the insulation fluid 38. The components include, for example, pressure tolerant capacitances and inductances. The insulation fluid 38 surrounds the pressure tolerant components of the switch main body 30 and the switch actuator 32. In another embodiment, the switch actuator 32 may be pressure sealed against the high pressure by a differential pressure barrier (not shown) so that the switch actuator 32 may employ non-pressure tolerant components. The differential pressure barrier may have thick metal walls.
The pressure compensators 36 are in fluid communication with the housing 34 and have a variable volume to regulate the pressure inside the housing 34 equal to external pressure surrounding the housing 34. The pressure compensators 36 are filled with the insulation fluid 38 and are transformable according to the external pressure. The pressure compensators 36 are made of elastic material, such as rubber. In one embodiment, the pressure compensators 36 include transformable bellows. In another embodiment, the pressure compensators 36 may include any other devices which have variable volume. The volume of the insulation fluid 38 may be changed because of external temperature or pressure, and the volume of the pressure compensators 36 is changed as the change of the volume of the insulation fluid 38 to balance the pressure of the insulation fluid 38 and the pressure surrounding the housing 34.
In the illustrated embodiment, the switch apparatus 14 includes one or more connectors 40 fluid hermetically coupled to the housing 34 and electrically connected with the switch main body 30. In this embodiment, the switch apparatus 14 includes an inlet circuit 42 and an outlet circuit 44, for example filter circuit, rectifying circuit, respectively coupled to the switch main body 30. The connectors 40 are respectively coupled to the inlet circuit 42 and the outlet circuit 44. The connectors 40 and the housing 34 are fluidly sealed such that the insulation fluid 38 is sealed in the housing 34. The connectors 40 may include a connector with low pressure difference because the pressure inside the housing 34 is substantially equal to the pressure outside and surrounding the housing 34. In one embodiment, the switch apparatus 14 may include any other devices or components.
The solid insulator 50 is moveable between the contacts 48 and 46, and operative to insulate the contacts 48 and 46. The dielectric strength of the solid insulator 50 is in the range of 80 kV/mm to 120 kV/mm. The solid insulator 50 is made of insulation material. In one embodiment, the material of the solid insulator 50 includes at least one of polypropylene, polytetrafluoroethylene (PTFE), poly dicyclopentadien (DCPD), solithane and silicon. In another embodiment, the solid insulator 50 may include any other solid insulation material with similar dielectric strengths.
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While the invention has been described with reference to exemplary embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 201410605171.7 | Oct 2014 | CN | national |
