Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L25/00—Assemblies consisting of a plurality of individual semiconductor or other solid state devices ; Multistep manufacturing processes thereof
  • H01L25/16—Assemblies consisting of a plurality of individual semiconductor or other solid state devices ; Multistep manufacturing processes thereof the devices being of types provided for in two or more different main groups of groups H01L27/00 - H01L33/00, or in a single subclass of H10K, H10N, e.g. forming hybrid circuits
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
  • H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
  • H02M7/003—Constructional details, e.g. physical layout, assembly, wiring or busbar connections
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
  • H05K7/00—Constructional details common to different types of electric apparatus
  • H05K7/14—Mounting supporting structure in casing or on frame or rack
  • H05K7/1422—Printed circuit boards receptacles, e.g. stacked structures, electronic circuit modules or box like frames
  • H05K7/1427—Housings
  • H05K7/1432—Housings specially adapted for power drive units or power converters
  • H05K7/14339—Housings specially adapted for power drive units or power converters specially adapted for high voltage operation
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L25/00—Assemblies consisting of a plurality of individual semiconductor or other solid state devices ; Multistep manufacturing processes thereof
  • H01L25/03—Assemblies consisting of a plurality of individual semiconductor or other solid state devices ; Multistep manufacturing processes thereof all the devices being of a type provided for in the same subgroup of groups H01L27/00 - H01L33/00, or in a single subclass of H10K, H10N, e.g. assemblies of rectifier diodes
  • H01L25/10—Assemblies consisting of a plurality of individual semiconductor or other solid state devices ; Multistep manufacturing processes thereof all the devices being of a type provided for in the same subgroup of groups H01L27/00 - H01L33/00, or in a single subclass of H10K, H10N, e.g. assemblies of rectifier diodes the devices having separate containers
  • H01L25/11—Assemblies consisting of a plurality of individual semiconductor or other solid state devices ; Multistep manufacturing processes thereof all the devices being of a type provided for in the same subgroup of groups H01L27/00 - H01L33/00, or in a single subclass of H10K, H10N, e.g. assemblies of rectifier diodes the devices having separate containers the devices being of a type provided for in group H01L29/00
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
  • H01L2924/0001—Technical content checked by a classifier
  • H01L2924/0002—Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
  • H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
  • H02M7/66—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output with possibility of reversal
  • H02M7/68—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output with possibility of reversal by static converters
  • H02M7/72—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output with possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
  • H02M7/75—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output with possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a thyratron or thyristor type requiring extinguishing means
  • H02M7/757—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output with possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a thyratron or thyristor type requiring extinguishing means using semiconductor devices only
  • H02M7/7575—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output with possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a thyratron or thyristor type requiring extinguishing means using semiconductor devices only for high voltage direct transmission link
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
  • H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
  • H02M7/66—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output with possibility of reversal
  • H02M7/68—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output with possibility of reversal by static converters
  • H02M7/72—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output with possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
  • H02M7/79—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output with possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
  • H02M7/797—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output with possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
  • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
  • Y02E60/60—Arrangements for transfer of electric power between AC networks or generators via a high voltage DC link [HVCD]

Definitions

• the present disclosure relates generally to the field of high voltage power converters and is concerned with electrical insulation in a valve unit of such high voltage power converters.
• the present disclosure relates in particular to a valve unit in which insulation is obtained by means of a gas and an insulating solid material.
• the valve unit of the present disclosure may be applicable in for instance offshore platforms.
• a high voltage direct current (HVDC) converter station is a type of station adapted to convert high voltage direct current (DC) to alternating current (AC) or the reverse.
• An HVDC converter station may comprise a plurality of elements such as the converter itself (or a plurality of converters connected in series or in parallel), an alternating current switch gear, transformers, capacitors, filters, a direct current switch gear and other auxiliary elements.
• Electronic converters may be categorized as line- commutated converters using e.g. thyristors as switches or voltage source converters using transistors, such as insulated gate bipolar transistors (IGBTs), as switches (or switching devices).
• IGBTs insulated gate bipolar transistors
• a plurality of solid-state semiconductor devices, such as thyristors or IGBTs may be surrounded by capacitors and connected together, for instance in series, to form a building block or a valve unit of an HVDC converter.
• a challenge in the construction and design of an HVDC converter station is the electrical insulation of the different parts of the HVDC converter station since an increased in distance between the various parts of an HVDC converter station improves insulation but at the same time results in an HVDC converter station with larger dimensions. This may raise a number of difficulties relative to e.g. installation, transport and cost, in particular for offshore applications. For at least such
• An object of at least some embodiments of the present disclosure is to wholly or partly overcome the above disadvantage of prior art systems and to provide a more compact alternative to the prior art.
• a valve unit comprising an enclosure, a plurality of cells and a high voltage (HV) shield arrangement.
• the enclosure extends along an axial direction and includes a solid insulating material.
• the enclosure is at least partially filled with an insulating gas.
• the plurality of cells is arranged as a stack within the enclosure.
• the stack comprises a plurality of capacitor shield elements, wherein two successive cells of the stack are separated by a capacitor shield element.
• the HV shield arrangement is disposed between the enclosure and the stack.
• the HV shield arrangement includes at least one HV shield electrode at least partially inserted in the enclosure and in electrical contact with at least one of the capacitor shield elements.
• electrical insulation is obtained by means of a gas and a solid insulating material. Insulation between the cell stack and ground, i.e. an outer surface of the enclosure (which may be coated with an electrically conducting layer or which may be a metallic container) is obtained by the solid insulating material of the enclosure while insulation between the cells is obtained via the gas enclosed in the enclosure.
• the HV capacitor shields of the cell stack present a high electric potential relative to ground.
• the contact between the HV capacitor shield elements and the HV electrodes inserted in the insulating enclosure prevent partial discharges in the gas because the solid insulation is subject to the high voltage of the HV capacitor shields to ground.
• the insulating solid material of the enclosure may present a high insulation strength as compared with gases, which is a property that the design of the valve unit defined in the above embodiment takes advantage of.
• the voltages between the cells and the enclosure apply to the insulating solid material, which may have higher electrical breakdown properties than e.g. air or other fluid cooling mediums used for insulation.
• the distance required for insulation in a radial direction i.e. in a direction transverse (e.g. perpendicular) to the axial direction of the enclosure, is reduced.
• the enclosure may be made of solid insulating material but may also be coated with an electrically conducting layer on its outer surface or inserted within a metallic container for grounding.
• the cell stack may includes a number of cells and HV capacitor shields (or HV corona shields).
• the cell stack is arranged along the axial direction (along which the enclosure extends) such that a number of positions is defined along the axial direction and cells are arranged at such positions.
• the HV shield arrangement may include a plurality of HV shield electrodes, each electrode being in electrical contact with a capacitor shield element of the stack.
• the present embodiment defines a first configuration in which a plurality of HV shield electrodes (or elements) is arranged along the axial direction.
• a succession of disc-shaped HV shield electrodes may be arranged along the axial direction of the cylinder such that an HV shield electrode (or element) contacts a HV capacitor shield element of the stack.
• the HV shield electrodes may have the form of toroids.
• the HV shield arrangement may comprise an electrically conducting member extending along the axial direction and being at least partially inserted in the enclosure.
• the electrically conducting member may be in contact with at least one HV shield electrode.
• the present embodiment defines a second configuration in which, instead of a plurality of HV shield electrodes, an electrically conducting member is arranged along the axial direction.
• a contact between the HV shield member and one of the HV capacitor shield elements may be established by means of an HV shield connector.
• the HV shield member may be casted in the insulating material of the enclosure.
• the HV shield member may have a shape conforming the shape of an inner wall of the enclosure. In a specific example, the HV shield member may have a cynlidrical shape.
• the HV shield arrangement may, according to an embodiment, include a single HV shield connector disposed between the conducting member and one of the HV capacitor shield elements.
• the single HV shield connector may be in contact with an HV capacitor shield element located in a center position within the stack.
• the HV shield arrangement may include the electrically conducting member and only two HV shield electrodes at its edges (extremities).
• the conducting member may extend from a first shield element (or electrode) located at one end of the stack to a second shield element (or electrode) located at another end (at the opposite side) of the stack.
• the thickness of the enclosure may be even further reduced, especially in the region between the two oppositely arranged electrodes.
• the at least one HV shield electrode may be totally embedded or inserted in the insulating material of the enclosure.
• the HV shield electrode may be casted in the solid insulating material with a contacting area on an inner surface (or inner wall) of the enclosure.
• the HV shield electrodes may also be referred to as HV insert electrodes.
• the solid material of the enclosure may be a polymer. More specifically, the solid insulating material of the enclosure may include epoxy or a thermoplastic material.
• the insulating gas may be at least one of sulfur hexafluoride (SF 6 ), Nitrogen (N 2 ), air and dry air.
• SF 6 sulfur hexafluoride
• N 2 Nitrogen
• the gas may be a mixture of different gases such as a mixture of SF 6 and N 2 .
• the gas may be under pressure such that it may in the following be referred to as a compressed gas.
• the enclosure may be made of epoxy and the gas may be SF 6 .
• the combination of SF 6 and epoxy is only an example and other gases and other solid materials may also be used for insulation.
• a cell of the stack may comprise a capacitor element and at least one semiconductor component (including e.g. thyristors or IGBTs).
• the cell is a disk-type cell with a disk-shaped capacitor element within which the semiconductor components is arranged.
• At least one of the cells, a group of cells or the stack may be detachably arranged such that it is removable from the enclosure.
• the valve unit may further comprise at least one cap covering an end of the enclosure.
• the cap may comprise a portion extending along an outer wall of the enclosure.
• the cap may include an insulating material.
• the valve unit may further comprise a plug-in cable termination at one end of the enclosure for connection of a bus bar.
• a first plug-in cable termination may be arranged at a first base of the cylinder-like enclosure and a second plug-in cable termination may be arranged at a second base of the cylinder-like enclosure opposite to the first base.
• a high voltage direct current (HVDC) converter or a HVDC converter station, comprising a valve unit as defined in any one of the preceding embodiments is provided.
• HVDC converter comprising at least two valve units as defined in any one of the preceding embodiments is provided. Different arrangements of the valve units are possible.
• At least two of the valve units may be coaxially arranged.
• the HVDC converter extends more in the axial direction, this embodiment provides a more compact solution in the radial direction.
• a spacing element including insulating material may be arranged at a junction between the at least two valve units.
• the spacing element comprises a first portion extending in a direction transverse to the axial direction and a second portion extending along at least one of an outer wall of an enclosure of a first valve unit and an outer wall of an enclosure of a second valve unit.
• At least two of the valve units may be arranged side by side and a cable termination output of a first one of the at least two valve units may be connected to another one of the at least two valve units.
• the cable may be either one of a bus bar embedded in an insulating material or a cable arranged external to the two valve units.
• the present disclosure is applicable for high voltage power equipments with various voltage levels in which it is desired to provide an insulated environment.
• the present disclosure is generally advantageous for applications in which a more compact power equipment is desired, such as in applications where space for installation of the electric power equipment is limited and/or for offshore wind farm applications.
• Figure 1 shows a schematic view of a valve unit in accordance with an embodiment
• Figure 2 shows a schematic view of a valve unit in accordance with another embodiment
• Figure 3 shows a schematic view of a cell in accordance with an embodiment
• Figure 4 shows a schematic view of a valve unit with a cap covering one end of the enclosure of the valve unit, according to an embodiment
• Figure 5 shows a schematic view of an arrangement of valve units of an
• Figure 6 shows a schematic view of an arrangement of valve units of an HVDC converter in accordance with another embodiment
• Figure 7 shows a schematic view of an arrangement of valve units of an HVDC converter in accordance with another embodiment.
• Figure 8 shows a schematic view of an arrangement of valve units of an HVDC converter in accordance with another embodiment.
• valve unit 100 With reference to Figure 1, a valve unit 100 according to an embodiment is described.
• Figure 1 shows a cross-sectional view of a valve unit 100 comprising an enclosure 130 and a plurality of cells 120 arranged as a stack within the enclosure 130.
• the cells 120 are arranged on top of each other and connected in series to form an electrical equipment or system within the enclosure 130.
• the enclosure 130 extends mainly along an axial direction 112 and may for instance have a cylinder- like shape extending from one flange (or base surface or region) 118 to another flange (or other base surface or region) 119.
• the enclosure 130 may be made of an insulating solid material.
• the enclosure 130 is a cylinder extending along the axial direction 112 and the cells 120 are arranged on top of each other along the axial direction 112, thereby defining a number of cell positions along the axial direction 112.
• the enclosure 130 may include an electricaly conductive layer 110 or may be inserted within a metallic container 110. The electrically conductive outer surface 110 of the enclosure 130 may be used for grounding.
• a cell may include a capacitor element and a semiconductor component.
• High voltage capacitor shields denoted 122 are arranged between the cells 120 such that two successive cells 120 in the stack are separated by an HV capacitor shield 122.
• a cell 120 is sandwiched between (or arranged adjacent to) two HV capacitor shields 122.
• an HV capacitor shield may as well be considered to be part of a cell such that a cell includes a semiconductor component, a capacitor element and its capacitor shield, in which case the stack includes a succession of cells disposed on top of each other.
• the capacitor shield of a cell would then be defined to be arranged adjacent to the next cell.
• the cells 120 are arranged as a stack with an intermediate HV capacitor shield 122 between two successive cells 120.
• the outer surface 110 of the enclosure 130 may be made of an electrically conducting material, such as a metal, or may be covered by an electrically conducting material such that the outside surface of the enclosure 130 may be grounded.
• the enclosure 130, including the metallic coating or metallic contrainer 110, may be closed or sealed by one or more covers arranged at the ends or base surfaces of the enclosure 130.
• the enclosure 130 is at least partially filled with an insulating gas 115, which may for example be SF 6 , N 2 , air, dry air or a mixture of such gases. It will be appreciated however that the present disclosure is not limited to these examples and that other gases, in particular SF6-free gases, with similar insulation properties may be used. Further, a compressed gas with pressure of approximately a few bars may be used. For example, the enclosure 130 may be filled with SF 6 at a pressure of 2 bars.
• the insulating material of the enclosure 130 may be a polymer such as epoxy or a thermoplastic polymer. It will be appreciated however that the present disclosure is not limited to these examples and that other insulating solid material with similar properties for insulation and for manufacturing purposes may be envisaged.
• the valve unit 100 further comprises an HV shield arrangement 140 disposed between the enclosure 130 and the stack of cells 120.
• the HV shield arrangement 140 may include at least one HV shield electrode 142 at least partially inserted in the enclosure 130 and in electrical contact with at least one of the capacitor shield elements 122.
• the HV shield arrangement 140 includes a plurality of HV shield electrodes or elements 142, each contacting a capacitor shield element 122 of the stack.
• the HV shield elements 142 may be made of an electrically conducting material such as a metal.
• each of the cells 120 is connected with an HV shield electrode 142.
• the HV shield electrodes 142 may be toroid-shaped so as to conform to the shape of the enclosure 130.
• Figure 1 shows also a particular configuration in which the HV shield electrodes 142 may be at least partially embedded or inserted in the insulating material of the enclosure 130.
• the plurality of HV shield electrodes is distributed along the axial direction 112 at positions corresponding to the emplacements (positions) of the cells 120 (or HV capacitor shields 122).
• the HV shield elements 142 and the enclosure 130 may as such form a single mechanical block in the valve unit and the stack of cells may be detachable (or removable) from such mechanical block, which is advantageous for example for repair or replacement of a cell of the stack, a group of cells or even the whole stack.
• the stack of cells 120 may be inserted or removed from the enclosure 130 by removing the flanges 118, 119 mounted at the ends of the cylinderlike enclosure 130, thereby opening the enclosure 130.
• the cylinder- like stack may glide along the axial direction 112 within the cylinder- like enclosure 130.
• the valve unit 100 may then be equipped with a fastening means (or holder) for maintaining the stack of cells along the axial direction 112 in a position at which the HV shield elements 142 connect to the HV capacitor shields 122.
• a fastening means or holder
• Figure 1 also shows that the valve unit 100 may comprise two plug-in cable terminations (or cable terminals or cable connectors) 160, one at each end of the enclosure 130, for connection of a bus bar to and from the valve unit 100.
• the plug-in cable terminations 160 may be designed to prevent leakage of insulating gas from the enclosure 130, i.e. the plug-in cable termination may be arranged to seal the enclosure 130.
• An external bus bar for connection to another valve unit, or for connection to an electrical system, may be connected to an (internal) conducting lead, or some kind of cable, connecting the cells 120 together within the enclosure 130.
• the valve unit 100 may for example be a converter and may be used for converting an incoming AC signal to an outgoing DC signal.
• valve unit 100 may be removable or modularized in order to facilitate their replacement without influencing the other elements.
• a cylinder-type HVDC converter with a number of cell positions such as described with reference to Figure 1 is advantageous over traditional offshore converter station as it avoids, or at least reduces, the need of clearance for manual access to the elements of the valve unit.
• Figure 1 therefore depicts a first configuration in which insulation between the capacitors is provided by an insulating gas and insulation between the cells/capacitors and ground is provided by a solid insulating material.
• a combination of epoxy as solid insulating material and SF 6 as compressed gas may be used.
• the voltages between the capacitors (or the HV capacitor shields 122) of the cells 120 and ground are exposed to the insulating solid material of the enclosure 130, e.g. an epoxy body.
• the insulation distance in the radial direction is dependent on the dielectric properties of the solid insulating material of which the enclosure or body 130 is made.
• the thickness of the enclosure 130 may be made smaller than with other insulating means, such as oil.
• the voltages between the capacitors of the cells 120 (which might be of approximately a few kV) will be exposed to the compressed gas enclosed within the enclosure 130.
• a suitable insulation distance is provided at each one of the ends of the enclosure 130 so that the interface between the plug-in cable termination 160 and gas and at the interface between the inner surface of the enclosure 130 and gas can withstand DC voltages to ground.
• valve unit 200 With reference to Figure 2, a valve unit 200 according to another embodiment is described.
• FIG. 2 shows a cross-sectional view of a valve unit 200 comprising an enclosure 230 with a metallic outer surface 210 and a plurality of cells 120 arranged as a stack within the enclosure 230.
• the cells 220 are arranged on top of each other with capacitor shields 122 arranged between two successive cells 120 (or being part of the cells 120).
• the valve unit 200 shown in Figure 2 is equivalent to the valve unit 100 described with reference to Figure 1 except that another type of HV shield arrangement 240 is used.
• the HV shield arrangement 240 comprises an electrically conducting member 244, a HV shield connector 242 and at least two HV shield elements or electrodes 246, 248.
• the electrically conducting member 244 may extend along the axial direction 212 (along which the enclosure 230 extends) and may be in at least partially inserted in the enclosure 230.
• the electrically conducting member is in contact with the HV shield electrodes 246, 248 and the HV shield connector 242.
• the electrically conducting member 244 is entirely casted or inserted in the insulating material of the enclosure 230.
• the electrically conducting member 244 may be formed at an inner surface of the enclosure 230 so that it conforms to the shape of the enclosure 230.
• the electrically conducting member 244 may therefore, in some embodiments, also have a cylindrical shape.
• the electrically conducting member 244 is in contact with the HV capacitor shield 122 of a cell 120 by means of an HV shield connector 242.
• the configuration shown in Figure 2 includes a single HV shield connector 242 between the electrically conducting member 244 and one of the cells 120.
• the single HV shield connector 242 is in contact with the HV capacitor shield 122' of the cell 120' located in a center position within the stack.
• the electrically conducting member 244 has therefore the same potential as the middle capacitor or HV capacitor shield 122'. Placing the HV shield connector 242 at the middle valve cell position capacitor decreases the maximum voltage between the HV capacitor shields 122 and the electrically conducting member 244 arranged in the enclosure 230.
• the electrically conducting member 244 may extend between at least two HV shield elements arranged at its extremities, i.e. a first HV shied element 246 arranged in contact with the electrically conducting member 244 at an end of the stack of cells (i.e. at a first cell of the stack) and a second HV shield element 248 arranged in contact with the electrically conducting member 244 at an opposite end of the stack of cells (i.e. at a last cell of the stack).
• the HV shield electrodes 246, 248 may be at least partially, and even in some embodiments totally, embedded (inserted) in the insulating solid material of the enclosure 230.
• the HV shield electrodes 246, 248 may be arranged at edges of the electrically conducting member 244 so that the local field enhancement in the solid material near the edges can be improved.
• the HV shield electrodes 246, 248 may be arranged at the same positions as the first cell and the last cell in the stack along the axial direction 212.
• the HV shield elements 246, 248 may be toroid-shaped or in the form of a ring.
• the enclosure 230 of the valve unit 200 shown in Figure 2 may be kept thinner, at least between the electrodes 246, 248 arranged at the extremities of the electrically conducting member 244, than the enclosure 130 of the configuration of the valve unit 100 described with reference to Figure 1. It will be appreciated however that the thickness of the insulating material of the enclosure 230 may vary along the axial direction 212, and in particular the insulating body 230 may be thicker at the extremities of the electrically conducting member 244 at which the HV shield elements 246, 248 are arranged. In other words, in the configuration shown in Figure 2, there is only one cylinder- like shield
• valve unit 200 may therefore be made lighter.
• FIG. 3 shows a cell 120 including a capacitor element 125 and a semiconductor component 127.
• the capacitor element 125 surrounds the semiconductor component 127 and is disc-shaped.
• the capacitor element 125 comprises a center hole in which the semiconductor component 127 may be placed.
• the cell 120 shown in Figure 3 is therefore particularly suitable for a cylinder-like enclosure.
• the semiconductor component may be an arrangement of one or more thyristors or IGBTs, depending on the desired electrical equipment (e.g. type of converter).
• a plurality of cells 120 may be arranged on top of each other to structurally form a stack (such as a cylinder in the case of a superposition of a plurality of disc-shaped cells) and electrically connected together to form the desired electrical equipment.
• a stack such as a cylinder in the case of a superposition of a plurality of disc-shaped cells
• the HV capacitor shields 122 are described as separate elements, distinct from the cells 120, the cell 120 may also be defined to further include such an HV capacitor shield arranged on top of the capacitor element 125.
• FIGs 1 and 2 show examples of multilayered converters which may comprise cells such as described with reference to Figure 3. It will be appreciated that two successive cells in the stack may be identical or different from one to another.
• valve unit 400 With reference to Figure 4, a valve unit 400 according to another embodiment is described.
• Figure 4 shows a valve unit 400 which is similar to the valve unit 100 described with reference to Figure 1 except that the valve unit 400 comprises at least one cap 450 covering at least one of the ends 119a, 119b of the enclosure 130.
• Figure 4 shows an embodiment wherein a cap 450 is mounted at each one of the ends 119a, 119b of the enclosure 130. As the two caps shown in Figure 4 are similar, reference will only be made to the cap 450 arranged at the end 119a of the enclosure 130. It will be appreciated however that the valve unit 400 is symmetric and that the same applies to the cap 450 arranged at the end 119b of the enclosure 130.
• Figure 4 shows two schematic views, wherein the left-hand side view shows the caps 450 being detached from the ends 119a, 119b of the enclosure 130 while the right- hand side view shows the caps 450 mounted at the ends 119a, 119b of the enclosure 130.
• the cap or cover 450 may be shaped as a hat matching the shape of an end 119a of the enclosure 130.
• the cap 450 may be U-shaped and therefore fit (encapsulate) the end 119a of a cylindrically shaped enclosure 130.
• the enclosure 130 may include a flange (or stop) 113 in the form of a protrusion or ring at its outer wall such that the cap 450 abuts on the flange (or stop) 113 when mounting it at one end of the enclosure 130.
• Figure 4 shows a first flange 113 arranged in proximity to one end 119a of the enclosure 130 and a second flange 114 arranged in proximity to an opposite end 119b of the enclosure 130.
• the region of the outer wall of the enclosure 130 extending from the first flange 113 to the second flange 114 may be made of, or coated by, an electrically conductive material (e.g. metal) and may be grounded for operation of the valve unit.
• the cap or cover 450 may be made of a solid insulating material such as a polymer, e.g. epoxy or a thermoplastic material, as represented by the body denoted 454 in figure 4, and may be coated by an electrically conducting material such as metal at the outside surface of the body 454. Portions of the cap 450 (or the legs of the U- shaped cap) may extend along an outer wall of the enclosure 130, which provides a longer path for flashover events.
• the cap 450 may during operation of the valve unit be grounded. With the cap 450, the dimensions required for clearance between a cell of the stack and an extremity (or end) of the enclosure 130 is reduced, thereby further enhancing the compactness of the valve unit.
• valve units With reference to Figures 5-8, different possible arrangements of valve units to form a larger HVDC converter are described.
• Figure 5 shows a first alternative of an arrangement 700 in which two valve units 740, 745 are coaxially arranged.
• Figure 5 shows a first valve unit 735 similar to the valve unit 400 described with reference to Figure 4 with a cap 750 mounted at one end of the valve unit 735 except that another valve unit 745 is connected at the opposite end of the valve unit 735 instead of having another cap (in comparison to the valve unit 400 of Figure 4).
• the arrangement 700 includes therefore also a second valve unit 745 which may be similar to any one of the valve units described above with reference to Figures 1-4.
• the second valve unit 745 is an intermediate valve unit in the arrangement 700 and does not include any cap.
• valve units 735 and 745 are arranged along the axial direction 112 and a specially designed spacing element (or spacer) 770 including insulating material, such as epoxy, is arranged at the junction between the first valve unit 735 and the second valve unit 745.
• the spacer 770 reduces the requirement for clearance between the two valve units, thereby providing a more compact arrangement.
• the spacer 770 may comprise a first portion 776 extending in a direction transverse to the axial direction 112 for separating the first valve unit 735 from the second valve unit 745.
• the spacer (or joint) 770 may also comprise a second portion 774 extending along the outer walls of the enclosures of the first valve unit 735 and the second valve unit 745.
• the second portion 774 extends from a second flange 114 of the first valve unit 735 to a first flange 113 of the second valve unit 745.
• the flanges 113, 114 may be used for connection of two valve units.
• Figure 6 shows another embodiment of an arrangement 800 in which three valve units 100 are arranged side by side.
• Each of the valve units may be similar to any one of the valve units described in the preceding embodiments with reference to Figures 1-4.
• Figure 6 depicts valve units being closely resembling the valve unit described with reference to Figure 1.
• a cable termination output of a first one of the valve units is connected via a cable 805 to another one of the valve units.
• a valve unit 100 may for example be connected to other valve units by insulated cables 805 (such as cross-linked polyethylene, XLPE, cables) via the plug-in cable terminations 160.
• Figure 7 shows another embodiment of an arrangement 900 comprising six valve units 990-995. Each of the valve units may be equivalent to any one of the valve units described in the preceding embodiments with reference to Figures 1-4.
• Figure 7 depicts an arrangement in which a first valve unit 990 may be arranged on the side of an arrangement of two valve units, namely the second valve unit 991 and the third valve unit 992, coaxially arranged such as described in e.g. Figure 5, i.e. by means of a spacer 926 arranged at the junction between the second valve unit 991 and the third valve unit 992.
• FIG. 7 shows an embodiment in which a so lid- insulated bus bar 908 connecting the first valve unit 990 with the second valve unit 991 is filled of a solid insulating material similar to the insulating material (e.g. epoxy) of the layer disposed at the inner sidewalls of the enclosures of the valve units 990, 991.
• a so lid- insulated bus bar 908 connecting the first valve unit 990 with the second valve unit 991 is filled of a solid insulating material similar to the insulating material (e.g. epoxy) of the layer disposed at the inner sidewalls of the enclosures of the valve units 990, 991.
• the first valve unit 990 is arranged on the side of the coaxial arrangement of the second valve unit 991 and the third valve unit 992, and a bent solid- insulated bar including a conductor 906 and the solid insulating material is used to connect the first valve unit 990 with the second valve unit 991.
• the third valve unit 992 is connected to the fourth valve unit 993 by means of a solid-insulated busbar 908 including a conductor 906.
• the arrangement shown in Figure 7 is symmetric such that the fourth valve unit 993 and the fifth valve unit 992 are connected and arranged in a similar manner as the second valve unit 991 and the third valve unit 992.
• the sixth valve unit 995 is connected to the fifth valve unit 994 in a similar manner as the first valve unit 990 is connected to the second valve unit 991.
• each of the first valve unit 990 and the sixth valve unit 991 is equipped with one plug-in cable termination 160 for connection to an electrical system (or to an external bus bar).
• Figure 8 shows another embodiment of an arrangement 1000 comprising three valve units 1110-1130. Each of the valve units 1110-1130 may be similar to any one of the valve units described in the preceding embodiments with reference to Figures 1-4.
• Figure 8 depicts an arrangement in which a first valve unit 1110 may be coaxially arranged with a second valve unit 1120 such as described in e.g. Figure 5, i.e. by means of a spacer 1126 arranged at the junction between the first valve unit 1110 and the second valve unit 1120.
• the second valve unit 1120 is connected to a third valve unit 1130 by means of a gas-insulated nodal element 1050 such as used in gas insulated stations.
• a gas-insulated nodal element 1050 such as used in gas insulated stations.
• the gas-insulated nodal element 1050 does not involve any cable or bus bar in open air, which is advantageous in offshore applications.
• Figure 8 shows an L-shaped nodal element 1050 which provides a 90 degrees turn in the arrangement of the valve units.
• the axial direction along which the enclosures of the first and second valve units 1110 and 1120 extend is perpendicular to the axial direction along which the enclosure of the third valve unit 1130 extends.
• the L-shaped nodal element 1050 is separated from the second valve unit 1120 by means of a spacer 1127 such as described with reference to Figure 5 and from the third valve unit 1130 by means of another spacer 1128.
• the L-shaped nodal element 1050 may be an L-shaped pipe filled with an insulating gas, such as e.g. SF 6 , N 2 , dry air or a mixture of such gases, and further includes an H conductor 1056 for connection of a last cell of the second valve unit 1120 with a first cell of the third valve unit 1130.
• an insulating gas such as e.g. SF 6 , N 2 , dry air or a mixture of such gases
• each of the first valve unit 1110 and the third valve unit 1130 is equipped with one plug-in cable termination 160 for connection to an electrical system (or to an external bus bar).

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• Engineering & Computer Science (AREA)
• Microelectronics & Electronic Packaging (AREA)
• Power Engineering (AREA)
• Physics & Mathematics (AREA)
• Condensed Matter Physics & Semiconductors (AREA)
• General Physics & Mathematics (AREA)
• Computer Hardware Design (AREA)
• Fuel Cell (AREA)
• Gas Exhaust Devices For Batteries (AREA)
• Electric Double-Layer Capacitors Or The Like (AREA)
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• 2014
  • 2014-07-16 WO PCT/EP2014/065250 patent/WO2016008518A1/en active Application Filing
  • 2014-07-16 EP EP14742183.8A patent/EP3170233A1/de not_active Withdrawn
  • 2014-07-16 CN CN201480080633.6A patent/CN106663924A/zh active Pending
• 2015
  • 2015-01-19 WO PCT/EP2015/050891 patent/WO2016008598A1/en active Application Filing
  • 2015-01-19 CN CN201580041940.8A patent/CN106575651B/zh active Active
  • 2015-01-19 GB GB1700980.4A patent/GB2543982B/en active Active

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