DE112015007244T5 - Valve unit for HVDC converters - Google Patents

Abstract

The present disclosure relates to a valve unit comprising a container, a plurality of power converter cells, a plurality of holding elements and a plurality of connecting elements for mechanically connecting the holding elements. The container may be at least partially filled with an electrically insulating gas and may extend along an axial direction. The plurality of power converter cells may be arranged as at least one column in the container. A holding element is arranged to hold at least one power converter cell. The connecting elements extend from a first holding element to another within a limited by an outer circumference of a arranged between the holding elements power converter cell space.

Description

TECHNICAL AREA

The present disclosure relates generally to the field of high voltage power converters and is concerned with a valve assembly in which insulation is obtained by means of at least one insulating gas. The valve unit of the present disclosure may be applied to, for example, offshore platforms.

BACKGROUND

A high voltage direct current (HVDC) converter station is a type of station designed to convert high voltage direct current (DC) to AC (AC) or vice versa. An HVDC converter station may comprise a plurality of elements, such as the converter itself (or a plurality of series or parallel converters), an AC switchgear, a transformer, capacitors, filters, a DC switchgear and other ancillary elements. Electronic power converters may be categorized as line-commutated power converters using, for example, thyristors as switches, or live-type power converters using transistors, such as insulated gate bipolar transistors (IGBTs), as switches (or switching devices). Several solid state semiconductor devices, such as the thyristors or IBGTs, may be surrounded by capacitors and interconnected, for example, in series, to form a device or valve assembly of a HVDC converter.

In designing and designing a HVDC converter station, there is a challenge in electrically isolating the various parts of the HVDC converter station, as increasing the distance between the different parts of a HVDC converter station improves insulation but at the same time becomes an HVDC converter station with larger dimensions leads. This can entail several difficulties in terms of, for example, installation, transportation and costs, especially for offshore applications. At least for such applications, there is a general need for more compact solutions.

SHORT VERSION

It is an object of at least some embodiments of the present disclosure to fully or at least partially overcome the above disadvantage of prior art systems and to provide a more compact alternative to the prior art.

These and other objects are achieved by means of a valve unit as defined in the appended independent claim. Other embodiments are defined by the dependent claims.

According to a general aspect, a valve unit is provided. The valve unit comprises a container, a plurality of power converter cells, a plurality of holding elements and a plurality of connecting elements for mechanically connecting the holding elements. The container may be at least partially filled with an electrically insulating gas and may extend along an axial direction. The plurality of power converter cells may be arranged as at least one column in the container. A holding element is arranged to hold at least one power converter cell. The connecting elements extend from a first holding element to another within a limited by an outer circumference of a arranged between the holding elements power converter cell space.

It is understood that the holding elements and the connecting elements together can form a support structure. By the term support structure is meant a structure which serves to support the stack of power converter cells. The support structure may for example also be referred to as a support, support means or support structure.

By the term "container" is also meant a housing or container in which a plurality of power converter cells may be arranged to form the column of power converter cells. The container may extend along the axial direction between a first end (or base or extremity) and a second end (or base or extremity) located at two spaced locations along the axial direction. The distance between the two ends of the container along the axial direction corresponds to the height of the container.

The term "column" of power converter cells also means a stack of power converter cells, that is to say a plurality of power converter cells stacked one above the other. The plurality of power converter cells are arranged along the axial direction (or stacking direction), for example, a vertical direction, as a stack, thereby forming a column of power converter cells. As previously mentioned, such a column may be disposed in the container which is at least partially filled by the insulating gas, and it is understood that insulating gas may be present between two consecutive converter cells of the stack.

The present disclosure provides a valve assembly that includes a container that is at least partially filled with an electrically insulating gas and a cell stack with an internal support structure. Placing the connection elements of the support structure within the outer diameter bounded by a power converter cell located between the support elements reduces the need for isolation between adjacent power converter cells in that the connection elements (or generally the support structure) do not disturb (or at least less) the electric field around the power converter cells. This also reduces the requirement for the distance between the power converter cell and an inner wall surface of the container. As mentioned above, the electrical insulation of the converter cells is obtained by means of an insulating gas enclosed in the container. As a result, a more compact valve unit is obtained.

In the present embodiments, the connecting elements are arranged inside the stack of power converter cells in that the connecting elements are arranged between two (successive) holding elements within the outer circumference (for example, a diameter) of a power converter cell arranged between these two holding elements (or at one of them). It will be understood that the connecting elements may be located within the outer periphery of the stack, as defined by the outer periphery (s) of the stacking power converter cells, so that an inner support structure is obtained. As a result, a more compact valve unit, and thus a more compact installation of multiple valve units, can be obtained to form, for example, a HVDC converter station.

It will be understood that the retaining elements (and the support structure in general) enable carrying the weight of the power converter cells, that is, the installation. For this purpose, the holding elements are mechanically connected to one another via the connecting elements.

In general, at least some of the embodiments of the present disclosure provide a more compact valve unit in that the power converter cells surround the connectors, or at least insofar as the connectors are within the space defined by the outer circumference of the power converter cells (ie, the outer periphery of the column of power converter cells) ,

The holding elements may define a plurality of locations for arranging the power converter cells along the axial direction. It is understood that more than one power converter cell may be located at any location along the axial direction (in the column) and that in some cases a location may be empty. A location is determined by the intersection between the connecting elements and a holding element, wherein a holding element for receiving (supports) of one or more power converter cells is arranged.

It will be understood that in some embodiments, the axial direction may be a vertical direction so that the container (and thereby the valve unit) may be in a floor-standing position (or may be vertically aligned therewith).

According to one embodiment, the column may be arranged by power converter cells coaxial with the axial direction along which the container extends, thereby providing an even more compact valve unit.

In some embodiments, the container may have a cylindrical shape. Further, in some other embodiments, the column may be formed with disc shaped power converter cells, thereby forming a pillar also having a cylindrical shape, thereby providing an even more homogeneous electric field. As a result, the gas play (between the column and the side wall of the container) can be further reduced, and an even more compact valve unit is provided.

In general, it is understood that the container may contain an electrically conductive material, such as a metal. Alternatively, the container may be made of another material coated on its outer surface with an electrically conductive layer. The electrically conductive material or the coating of the container can then be used for grounding.

In some embodiments, the support members define a plurality of locations for the arrangement of the power converter cells along the axial direction, with a first location at or near a first extremity of the receptacle and a second location at or near an extremity of the receptacle opposite the first extremity located along the axial direction. In other words, the column of power converter cells may extend from an outermost end of the container to its opposite extreme end.

In some embodiments, the valve unit may further include at least one mounting member for attaching at least one of the retaining members and / or the connecting members a lower surface, an upper surface and / or a wall surface of the container. In one embodiment, the support structure may be mounted (or mounted) at one end at the bottom of the container when viewing the valve unit (and thereby the axially extending container) in a standing position, that is, in a substantially vertical axial direction; and the support structure may optionally be attached (or mounted) at the other end to the upper part of the container.

In some embodiments, the attachment member may include a shielding surface structure for smoothing the electric field within the container, which improves insulation. In a more specific embodiment, the attachment member (or shield) may be configured to extend along a direction that intersects a radial direction (that is, it is in a direction that is not substantially perpendicular to the direction) Axial direction along which the container extends runs). In other words, the attachment member may be designed to avoid horizontal surfaces on which particles fall (and accumulate), thereby impairing the surface insulation.

In some embodiments, at least a portion of a support member is integrated with a body of the power converter cell supported by the support member. In other words, the holding elements may be integrated parts of the power converter cells, so that a holding element is part of a body of a converter cell supported by the holding element. In particular, the lower part (body) of a power converter cell may be made thicker or provided with means for attachment to the connecting elements. Regardless of whether or not the retaining elements are integrated parts of the power converter cells, reference may still be made below to a supporting structure in order to refer to the connecting elements and the retaining elements. In some embodiments, the holding member may be an integrated part of the power converter cell, and thus it may be considered that the arrangement of the power converter cells themselves define locations along the axial direction.

According to some embodiments, the holding elements may be holding plates. However, it will be understood that a retaining element need not necessarily be a continuous plate, and that a retaining element that provides contact points on the connector elements may be sufficient for one or more power converter cells to abut at a location along the stacking direction.

According to an embodiment, a power converter cell may include a body extending in a radial direction between an outer circumference and an inner circumference, thereby defining an inner space. In other words, a power converter cell may include a body having an inner circumference (such as an inner diameter in the case of a circular or annular body) and an outer circumference (such as an outer diameter), thereby defining the inner space. The body of the power converter cell may include a cavity or cavity, for example, a through hole. It is understood that the outer peripheries of the power converter cells determine the outer circumference of the column of power converter cells. Although variation of the outer periphery of the column of power converter cells along the axial direction may be considered, in some embodiments the power converter cells may have substantially the same or approximately the same outer circumference, thereby providing a constant outer perimeter of the column of power converter cells in which the connectors are located , is defined along the axial direction.

According to one embodiment, the connectors may extend within the interior space (as defined by the superposition of the power converter cells), providing an even more compact valve unit, as the distance between two consecutive power converter cells in the column may be reduced.

According to some embodiments, the holding member may have a cross section (or a shape) about the axial direction corresponding to a cross section (or a shape) of the body of the power converter cell arranged over the axial direction on the holding member.

According to an embodiment, a holding member includes a middle through-hole having a circumference that corresponds to or is larger than the inner circumference of the body of a power converter cell arranged on the holding member. In particular, the middle through-hole of the holding element may have a shape which coincides with a shape of the surface of the inner space defining body of the power converter cell. It is understood that the through hole of the holding element may have different shapes, for example circular, elliptical, rectangular or square. Furthermore, the size of the through-hole may also vary.

In some embodiments, the circumference of the central through hole of the holding member may be larger than the inner circumference of the body of the power converter cell, in which case only a part of the body of the power converter cell on the Holding element rests. In other embodiments, the circumference of the central through-hole of the holding member may be substantially equal to the inner circumference of the body of the power converter cell. These embodiments provide prevention of surface sparkover that is aided by particulate contamination because there is a reduced range of horizontal surfaces of the holding members exposed to such particulates.

In still some other embodiments, in some embodiments, the perimeter of the central through hole of the holding member may be smaller than the inner circumference of the body of the power converter cell, in which case any device (or some of the devices) disposed in the inner space bounded interior space ), can abut the retaining element (can).

The body (or the condenser unit) of a power converter cell may be formed of a single part with a hole in which other electrical components, such as switching devices, may be arranged.

In other embodiments, the body may be divided into several parts. A part can then form a section of the body. The present embodiments provide a power converter cell having a body containing a plurality of parts or sections (particularly capacitive parts). These embodiments are advantageous in that they reduce eddy currents (or Foucault's currents) generated on the outer surface of the capacitor unit (that is, on the capacitor box or capacitor housing / container) when it contains an electrically conductive material. Eddy currents flow in closed circuits within electrically conductive materials (conductors) in planes perpendicular to the magnetic field. The size of the stream in a loop is proportional to, among other things, the area of the loop. Compared to a single part based capacitor unit, the use of several smaller parts divides the induction loop into smaller parts, thereby reducing the amplitude of the eddy currents.

According to some embodiments, the intersection of the plurality of connecting elements with a holding element may define a plurality of compartments on the holding element that correspond to the number of parts of the body arranged on the holding element. A part of the body can then be arranged in a compartment.

According to some embodiments, the connecting elements extending between a first holding element and a second holding element may be fixed to the first holding element between two adjacent parts of the body arranged on the first holding element.

According to an embodiment, an outer surface of a power converter cell (that is, the body or the capacitor unit of a power converter cell) may be elliptical, circular, and / or includes at least one rounded corner. In some embodiments, the power converter cells may be disc-shaped.

A circular body provides a smoother power converter cell profile, thereby reducing the need for isolation performance and providing other benefits, such as lower stray inductance in the current commutation loop. For example, the body (or condenser unit) of the power converter cell may be circular (or annular).

According to one embodiment, the valve unit may further comprise a first electrical shield at one end of the container and / or a second electrical shield at an opposite end of the container. The electrical shields may be removable parts of the container for easier insertion of the at least one column of power converter cells into the container.

According to one embodiment, the valve unit may further comprise at least one connector or a pluggable cable termination for electrically connecting a cell of the valve unit to one end of the container.

According to one embodiment, the valve unit may further comprise a spacer element containing insulating material and disposed at one end of the container for spacing the container from a receptacle of another valve unit to which the valve unit is connected.

According to one embodiment, the insulating gas may be sulfur hexafluoride (SF ₆ ) and / or nitrogen (N ₂ ) and / or air and / or dry air. It is understood that the gas may be a mixture of different gases, such as a mixture of SF ₆ and N ₂ . It is understood that the present disclosure is not limited to such gases and that other insulating gases may be considered. Further, the gas may be a pressurized gas, for example, a gas under a certain pressure higher than atmospheric pressure.

According to some embodiments, a connector may at least partially contain solid insulating material. In particular, each of the Connecting elements of the plurality of connecting elements contain an insulating material, whereby the electric potential separation between successive power converter cells is improved.

According to one embodiment, a converter station is provided. The converter station may comprise at least two valve units as defined in one of the preceding embodiments. The converter station may also be referred to as a high voltage direct current (HVDC) converter station.

It should be understood that other embodiments using all possible combinations of the features recited in the embodiments described above may be considered.

list of figures

• 1 zeigt eine schematische perspektivische Ansicht einer Haltestruktur (oder Stützstruktur) gemäß einer Ausführungsform;
• 2 zeigt eine schematische perspektivische Ansicht einer Ventileinheit, die ein Behältnis, das zumindest teilweise mit einem Isoliergas gefüllt ist, einen Zellenstapel und eine Stützstruktur gemäß einigen Ausführungsformen enthält;
• 3 zeigt eine schematische Ansicht einer Zelle gemäß einigen Ausführungsformen;
• 4 zeigt eine schematische allgemeine Ansicht eines Ventilstapels gemäß einigen Ausführungsformen;
• 5 zeigt eine schematische perspektivische Ansicht eines Körpers (oder einer Kondensatoreinheit) einer Stromrichterzelle gemäß einer Ausführungsform;
• Die 6A und 6B zeigen schematische Draufsichten von Körpern von Stromrichterzellen gemäß einigen Ausführungsformen;
• 7 zeigt eine schematische Ansicht eines Teils einer Kondensatoreinheit gemäß einer Ausführungsform;
• Die 8A und 8B zeigen schematische Ansichten von alternativen Ausführungsformen für die Montage von stückweisen Stromrichterzellen an einer Haltestruktur;
• 9 zeigt eine schematische Ansicht einer Ventileinheit eines HVDC-Stromrichters gemäß einer Ausführungsform;
• 10 zeigt eine schematische Ansicht einer Ventileinheit gemäß einer anderen Ausführungsform; und
• 11 zeigt eine schematische perspektivische Ansicht einer Ventileinheit gemäß noch einer anderen Ausführungsform.

Exemplary embodiments will now be described in detail with reference to the following appended drawings.

• 1 shows a schematic perspective view of a support structure (or support structure) according to an embodiment;
• 2 shows a schematic perspective view of a valve unit containing a container which is at least partially filled with an insulating gas, a cell stack and a support structure according to some embodiments;
• 3 shows a schematic view of a cell according to some embodiments;
• 4 shows a schematic general view of a valve stack according to some embodiments;
• 5 shows a schematic perspective view of a body (or a capacitor unit) of a power converter cell according to an embodiment;
• The 6A and 6B 12 show schematic plan views of bodies of power converter cells according to some embodiments;
• 7 shows a schematic view of a part of a capacitor unit according to an embodiment;
• The 8A and 8B show schematic views of alternative embodiments for the assembly of piece-wise power converter cells to a support structure;
• 9 shows a schematic view of a valve unit of a HVDC converter according to an embodiment;
• 10 shows a schematic view of a valve unit according to another embodiment; and
• 11 shows a schematic perspective view of a valve unit according to yet another embodiment.

As shown in the figures, the sizes of the elements, layers and regions may be exaggerated for illustrative purposes and are thus presented to illustrate the general structures of the embodiments. Like reference numerals refer to like elements throughout.

DETAILED DESCRIPTION

Hereinafter, exemplary embodiments will be described in more detail with reference to the accompanying drawings, in which currently preferred embodiments are shown. However, the invention may be embodied in many different forms and should not be interpreted as limited to the embodiments set forth herein; instead, these embodiments are presented for the sake of thoroughness and completeness and fully convey the scope of the invention to those skilled in the art.

With reference to 1 becomes a support structure 100 described the several retaining elements 121 - 124 and a plurality of connecting elements 141 - 144 includes.

Without restriction of generality shows 1 a support structure 100, which has several retaining plates 121 - 124 , which act as holding elements (or holding members), and a plurality of bars 141 - 144 which act as connecting elements comprises. The bars 141 -144 extend along an in 1 110 labeled axial direction. In particular, the rods extend 141 - 144 parallel to the axial direction 110 , and the holding plates 121 - 124 are at different locations along the axial direction 110 arranged in the axial direction 110 perpendicular intersecting planes. However, it is understood that the connecting elements need not necessarily be parallel to the axial direction 110 and that the retaining plates are not perpendicular to the axial direction 110 must be located.

The holding plates 121 - 124 are along the axial direction 110 separated by a gap, allowing the arrangement of power converter cells, as described in more detail below.

At the in 1 In the embodiment shown, the holding plates 121-124 of the support structure 100 circular or disc-shaped. However, other forms come into consideration. Further, each of the holding plates 121-124 includes a through hole so as to be formed as rings. A first holding plates 121 is, for example, disc-shaped with a through-hole indicated 151 in a middle part of the holding plate 121 is arranged. The middle through hole 151 of the holding plate 121 has a circumference that corresponds to the inner circumference of a body on the holding element 121 corresponds to the converter cell to be arranged. The bars 141 - 144 extend along the axial direction 110 and cut the retaining plates 121 - 124 near the through holes of the holding plates.

As mentioned above, according to some embodiments, the holding member may have a cross section (or a shape) about the axial direction corresponding to a cross section (or shape) of the body of the power converter cell to be arranged over the axial direction on the holding member. A holding member may include a center through hole having a circumference corresponding to or larger than the inner circumference of the body of a power converter cell to be disposed on the holding member. In particular, the middle through-hole of the holding element may have a shape which coincides with a shape of the surface of the inner space defining body of the power converter cell. It is understood that the through hole of the holding element may have different shapes, for example circular, elliptical, rectangular or square. Furthermore, the size of the through-hole may also vary.

In some embodiments, the circumference of the central through hole of the holding member may be larger than the inner circumference of the body of the power converter cell, in which case only a part of the body of the power converter cell abuts against the holding member. In other embodiments, the circumference of the central through-hole of the holding member may be substantially equal to the inner circumference of the body of the power converter cell. These embodiments provide prevention of surface sparkover that is aided by particulate contamination because there is a reduced range of horizontal surfaces of the holding members exposed to such particulates.

In still some other embodiments, the circumference of the central through hole of the holding member may be smaller than the inner circumference of the body of the power converter cell, in which case any device (or some of the devices) disposed in the inner periphery bounded interior is (are) can rest against the holding element (can).

The body (or the condenser unit) of a power converter cell may be formed of a single part with a hole in which other electrical components, such as switching devices, may be arranged.

Although 1 Holding plates as an example of holding elements, it is understood that other types of holding elements can be used. Generally, the holding members serve to hold one or more power converter cells at a location along the axial direction along which the stack of power converter cells extends (ie, the stacking direction). The holding elements can therefore be fixed at a certain point along the stacking direction. The holding member of a particular location may not be a continuous body or plate, but could be a number of holding members defining a plurality of contact points on each of the connecting members so that a power converter cell is installed thereon at a predetermined position along the stacking direction can. However, it should be understood that a single-body retainer, such as a retainer plate, that physically connects fasteners extending along the stacking direction is beneficial for supporting the weight of the power converter cells, thereby improving mechanical stability.

Although 1 It is understood that a support structure having a plurality of connecting elements and a plurality of holding elements can be integrated parts of the bodies of the power converter cells to be arranged at the locations defined by the holding elements along the axial direction. In these embodiments, the power converter cells may be provided with some attachment means for attaching the connecting elements.

In some embodiments, the connecting elements may be one or more rods, cables or tubes. The connecting elements may be designed to mechanically connect one holding element to another. For example, the support structure may include a plurality of retaining plates that include a plurality of holes for inserting a plurality of rods acting as connecting elements. The retaining plates may then be secured to the rods by some fasteners (or fasteners), such as screws or staples. In another example, the retaining elements may be soldered to the connecting elements.

According to some embodiments, the connectors may at least partially include (or be made of) solid insulating material. In particular, each of the connecting elements of the plurality of connecting elements Insulating material included, whereby the electrical isolation between successive power converter cells is improved.

With reference to 2 becomes a valve unit 200 described according to one embodiment.

2 shows a schematic perspective view of a valve unit 200 containing multiple power converter cells 130 - 139 , a support structure similar to that with reference to 1 described supporting structure with holding elements 121-124 (not all elements in the figure) and connecting elements 141 - 143 and a container 280 at least partially filled with insulating gas.

The valve unit 200 includes a container (or housing) 280 and multiple cells 130 - 139 acting as a stack (or pillar) within the housing 280 are arranged. The cells 130 - 139 are stacked and connected in series to an electrical equipment or system (for example a power converter) within the container 280 to build.

The container 280 may extend primarily along an axial direction 110 and may, for example, have a cylindrical shape extending from a base surface or a base region 288 to another base area or another base area 289 (that is, between two spaced locations along the axial direction 110 ). In a particular embodiment, the housing may 280 a cylinder that extends along the axial direction 110 extends, and the cells 130 - 139 are using a support structure, such as with reference to 1 described along the axial direction 110 arranged, creating multiple cell positions along the axial direction 110 To be defined.

As in 2 In some embodiments, the valve unit may include at least one attachment member for attaching at least one of the retention members and / or the fasteners 141 - 143 be equipped on a lower surface, an upper surface and / or a wall surface of the container. In one embodiment, the support structure may be mounted (or mounted) at one end at the bottom of the container when viewing the valve unit (and thereby the axially extending container) in a standing position, that is, in a substantially vertical axial direction; and the support structure may optionally be attached (or mounted) at the other end to the upper part of the container.

As further described in other embodiments, the attachment member may include a shielding surface structure for smoothing the electric field within the container, which improves insulation. In a more specific embodiment, the attachment member (or shield) may be configured to extend along a direction that intersects a radial direction (that is, it is in a direction that is not substantially perpendicular to the direction) Axial direction along which the container extends runs). In other words, the attachment member may be designed to avoid horizontal surfaces on which particles fall (and accumulate), thereby impairing the surface insulation.

As with reference to 3 Further, a cell may include at least a capacitor element and a switching device. The stack of power converter cells 130-139 may include high voltage capacitor (HV) capacitor shields in which the capacitor elements are disposed. The HV capacitor shield of a cell may surround the switching device. In other words, a capacitor shield of a cell acts as a cladding for the capacitor element. The capacitor shield may be formed as a toroid having a square cross section. In the stack, two successive power converter cells, each comprising a capacitor screen with a capacitor element and a switching device, are separated by the insulating gas located inside the container. In this configuration, an HV capacitor shield is considered to be part of a cell such that a cell includes a switching device, a capacitor element and its capacitor shield, the stack then containing a series of cells arranged with a certain gas gap between successive cells.

The outer surface of the housing 280 may be made of an electrically conductive material, such as a metal, or may be covered by an electrically conductive material, such that the outer surface of the housing 280 can be grounded.

Furthermore, the container 280 for electrical insulation between the power converter cells 130 - 139 for example, partly with an insulating gas 215 be filled, which may be, for example, SF ₆ , N ₂ , air, dry air or a mixture of such gases. It should be understood, however, that the present disclosure is not limited to these examples and that other gases, particularly SF ₆ -free gases, have similar insulating properties can be used. Further, a pressurized gas may be used at a pressure of about a few bars. For example, the housing 280 may be filled with SF ₆ at a pressure in a range of 2 to 6 bar.

In some embodiments, at least one of the cells, a group of cells, or the stack may be separable so that it may be removed from the container. In particular, the stack of cells may be separable (or removable) from the housing, which is advantageous, for example, for repairing or replacing a cell of the stack, a group of cells, or even the entire stack. On 2 Referring to, the stack of cells 130 - 139 by removing an upper part of the container 280 into the housing 280 used or removed from it. 2 shows that the container 280 may be made of at least two parts, a main part is a cylinder in which the cell stack is arranged, and an upper part is formed as a bottle neck, which rests on the main part by means of a flange 287 to a bottle-like container 280 to build. The cylinder-like stack with its inner support structure can along the axial direction 110 in the cylinder-like housing 280 slide.

In the in 2 shown valve unit 200 The stack of power converter cells may be coaxial with the axial direction 110 along which the container 280 extends, be arranged.

Although a cylindrical shape offers some advantages in terms of homogeneity of the electric fields induced in such a type of electrical equipment, it will be understood that the present disclosure is not limited to such a form of housing and other geometries are contemplated.

Further, the voltages of the capacitors of cells 130-139 (which could be about a few kV) become that in the housing 280 enclosed compressed gas exposed.

In the valve unit 200 For example, the plurality of power converter cells 130-139 are arranged as a stack along the axial direction 110. A power converter cell, for example the power converter cell designated 139, includes a body extending in a radial direction (in the present example, in a direction substantially perpendicular to the axial direction 110 extending direction) between an outer periphery and an inner periphery extends (see also FIG 3 for more details). Due to the arrangement of the power converter cells 130 - 139 on the holding plates 120 - 129 the support structure is an interior in the stack of power converter cells 170 educated.

In the in 2 As shown, each power converter cell is arranged on its own retaining plate. Thus, the holding plates define 120 - 129 a plurality of locations for the arrangement of the power converter cells 130-139 along the axial direction 110 , In particular, the power converter cells designated 130-139 are arranged on the respective retaining plates of the support structure designated 120-129. The support structure also includes a plurality of connectors, in the present example four rods 141-144 extending along the stacking direction 110 extend. The four rods are arranged to the holding plates 120 - 129 mechanically connect with each other. The bars 141 - 144 extend in the interior defined by the stacking of the power converter cells 130-139 170 , Although the specific embodiment of 2 Showing fasteners that extend within the interior of the stack, the fasteners may be described more generally than extending within the outer perimeter (and particularly the outer diameter) of the stack (as defined by the outer diameter of the stack forming power converter cells).

2 illustrates that the power converter cells, the connecting elements 141 - 144 surrounded the support structure. In particular, illustrated 2 in that the power converter cells may be annular and thus have a circular outer surface, thereby yielding a cylinder-like stack of cells. Other geometries are also possible; however, it is beneficial if the power converter cells (and the resulting stack of power converter cells) have a smooth outer surface with rounded corners.

With reference to 3 becomes a cell 130 described in more detail according to one embodiment.

3 shows a cell 130 including a body (or capacitor shield) 332 and a switching device, such as a device 337 Semiconductor-based. At least one capacitor element (not shown) is in the body (or in the capacitor shield 332 ), that is, through the interior of the body 332 defined volume, arranged or enclosed. The body 332 the power converter cell 130 extends between an outer circumference 160 and an inner circumference in a radial direction (in a direction substantially perpendicular to an axial direction as defined by the annular body) 162 ,

The capacitor shield 332 and their capacitor element disposed therein may be referred to as the capacitor unit (or body) of the power converter cell 130. At the in 3 the embodiment shown surrounds the body 332 the semiconductor device 337 and is disc-shaped. The body 332 is annular and defines a central hole in which the semiconductor device 337 can be placed. In the 3 shown cell 130 is therefore particularly suitable for forming a cylinder-like stack of power converter cells.

In the in 3 The example shows the body 332 an interior 370 by the body 332 the power converter cell 130 is defined. The semiconductor device 337 is inside the interior 370 arranged. The interior 370 In the illustration, it has a circular cross-sectional shape over the axial direction along which the power converter cell extends. However, the interior can also have a different geometry.

The internal space defined by the body of a power converter cell may have, for example, an elliptical cross-sectional shape, a circular cross-sectional shape, a polygonal cross-sectional shape, or a square cross-sectional shape across the axial direction. Although it is advantageous, although not always required, for the outer surface of the body to include rounded corners and to be circular, the interior space defined by the bodies of the power converter cells (or internal space) may vary depending on the desired arrangement of electrical components in the body Interior have different shapes. In a particular embodiment, the interior space defined by the hollow body may be square, which may provide an improved fill factor of the devices installed thereon. Further, the shape of the inner space may be adapted to the configuration (number, positioning) of the connecting elements extending in the inner space. In some embodiments, the inner circumference of the power converter cells (that is, the inner space) may be configured to receive the connecting elements. For example, depressions for inserting the connecting elements may be formed in the surface of the interior facing body, thereby leaving more room for any electronic components and / or other devices to be arranged in the internal space.

It should be understood that in some embodiments, the connecting elements may extend in a space (s) defined between (within) the outer circumference of a power converter cell and the inner circumference of the power converter cell. In other words, in some embodiments, the connectors may not reside within the space of the column (as defined by the superposition of the power converter cells), but outside the interior, but within the perimeter of the column (or outside diameters of the column forming power converter cells).

As mentioned above, an outer surface of the power converter cell (that is, the body or the capacitor unit of the power converter cell) may be elliptical, circular, and / or include at least one rounded corner. In some embodiments, the power converter cells may be disc-shaped. In particular, the power converter cell (or its body) may have a cylindrical shape or the shape of a parallelepiped. However, it will be appreciated that for the purposes of a HVDC power converter cell, a circular shape or at least a rounded corner shape is advantageous because it provides a smooth surface, which in turn facilitates high voltage isolation since there are fewer sharp curves and edges protrude. As a result, isolation distances can be shortened and, for example, coronary rings can be partially or completely avoided. The use of a capacitive body having an outer surface that includes rounded corners and is circular, for example, therefore offers the advantage that space can be used more efficiently, whereby the size of the converter station can be reduced.

According to a more general embodiment, the power converter cell may further comprise at least one capacitor element disposed in a body extending from the outer periphery to an inner circumference of the power converter cell and at least one switching device.

In such embodiments, the body may include at least one capacitor element, that is, the body may correspond to the capacitor part (or capacitor unit) of the power converter cell. In this regard, the dimensions of the body may determine the characteristics and, in particular, the potential capacitance and voltage of the converter of the power converter cell for a particular choice of materials. Further, the height of the body along the axial direction may be determined by the desired capacitance or desired voltage. The body can therefore also be referred to as a capacitive body or capacitor of the power converter cell.

By the term capacitor element is meant a device that acts as a capacitor, that is, acts as an electrical device for electrostatically storing energy in an electric field. A capacitor element (or capacitor) is normally formed by metal layers (or plates) between which an insulating medium is disposed.

For example, the switching device may be disposed within the interior space defined by the body of the power converter cell. The switching devices (eg, the semiconductor switches) may be arranged in a manner to more uniformly distribute the switched current around the area of the capacitive body, for example to reduce hot spot temperatures and increase the long term reliability of the capacitor.

The switching device may be a semiconductor-based switching device. For example, the switching device may include an insulated gate bipolar transistor (IGBT), a metal oxide semiconductor field effect transistor (MOSFET), an integrated gate commutated thyristor (IGCT), a gate turn-off (GTO) thyristor HEMT (high electron mobility transistor) and a HBT (hetero junction bipolar transistor) be. Other types of transistors (or semiconductor-based switching devices) may also be considered.

Further, it should be understood that the present disclosure is not limited to any particular semiconductor technology. It will be appreciated that silicon or silicon carbide based switching devices may be used, particularly, for example MOSFET, IBGTs, IGCTs and GTOs. Gallium-nitride or gallium-arsenide based switching devices may also be used, in particular, for example, HEMTs or HBTs. Other types of semiconductors that provide switching devices for high power applications may be considered.

It is understood that the power converter cell may further comprise other electrical components or devices. For example, the power converter cell may also include a cooling device and / or a bypass switch that allows a current to bypass the switching devices of a power converter cell in the event of failure of a switching device, thereby reducing the risk of damage to the components of a power converter cell caused, for example, by short circuit currents , The bypass switch may be a mechanical switch or an electrical switch, such as a thyristor. Further, the power converter cell may also include means for reducing the fault currents. Devices and devices other than those listed herein may be disposed within the interior space defined by the cell stack.

Multiple cells may be arranged one above the other along an axial direction (particularly, but not necessarily, a vertical direction) to form a stack of cells. The plurality of cells may be electrically interconnected via a bus bar element to form the desired electrical equipment.

4 shows an example of a valve stack 450 in which a plurality of power converter cells are arranged one above the other along an axial direction. The valve stack 150 contains a plurality of cells 130 - 139 , each of which with reference to 3 described power converter cell 130 may correspond. In the 4 The arrangement shown in FIG 2 correspond to the arrangement shown. 4 shows a cross-sectional view of the stack 450 of power converter cells with a switching device 337 that of a body or a capacitor shield 332 is surrounded. It is further understood that two consecutive cells in the stack may be the same or different from each other. 4 also shows a busbar 440 which serially connects the plurality of power converter cells 130-139 to form a larger power converter.

4 also shows that the retaining elements 120 - 129 between the power converter cells 130 - 139 can be arranged. In the illustrated example, a holding element is arranged between two successive power converter cells. In particular, the holding element may have a shape that corresponds to the shape of the body of the arranged on the holding element power converter cell.

In the illustrated configuration, the stack of power converter cells may be manufactured by successively mounting a holding member (such as a holding plate) and a power converter cell to the connecting members.

In the following, further embodiments using another type of power converter cells will be described.

With reference to 5 For example, a capacitor unit 500 of a power converter cell according to an embodiment will be described.

5 shows a schematic perspective view of the capacitor unit 500 , The condenser unit 500 includes four parts 501 - 504 , If the four parts 501 - 504 are mounted, they form a body extending along an axial direction 110.

Therefore, in these embodiments, the body (or condenser unit) of the power converter cell can not consist of a single part (or a single mechanical block), but consists of several (at least two) parts. The parts or "slices" in a circular capacitor form the capacitor unit when assembled together. It is understood that each of the parts or each of the sections is a subunit (or a subelement) of the capacitor unit and itself acts as a capacitor.

The condenser unit can be formed by mounting N parts, thereby facilitating the installation of the condenser unit in a valve unit of a power converter hall, since one of the N parts of the condenser unit is easier to handle than the whole condenser unit (that is, if the condenser unit is a single part would be made). A part or sub-element of a condenser unit also has a lower weight than the entire condenser unit (as compared to a single part that makes up the entire condenser unit).

In these embodiments, the body is formed of a plurality of parts that form a hole or cavity after assembly in which other electrical components may be disposed. The parts may be arranged side by side, that is in a close arrangement with a mechanical contact between two adjacent or successive parts. However, in some other embodiments, the body forming members may be located close together, but with a gap between two consecutive members. Thus, the body can also be formed by a loose arrangement of the parts, that is with a gap between the parts, which is advantageous because it relieves part of the pressure. The arrangement of the parts determines an outer periphery of the resulting power converter cell.

It should be understood that a portion of the capacitor unit (or body) itself may include a plurality of capacitor elements or partial capacitive elements interconnected (that is, functioning as a capacitor) to form a "capacitive" portion.

With reference to 5 limit the parts 501 -504 a room or area 570 , which is also referred to as the interior and the middle part or cavity of the condenser unit 500 equivalent. Each of the parts 501 - 504 forms a section of the body, and at least one of the parts is a separable section of the body. 5 illustrates that the part labeled 504 is separate from the other parts.

The condenser unit 500 can have different shapes. In some embodiments, an outer surface 506 of the body of the condenser unit 500 be circular, such as in 5 but it may also be considered that the outer surface of the body of the condenser unit is elliptical and / or rectangular or square or has some other shape. However, it may be obvious that the outer surface of the body of the condenser unit 500 may advantageously comprise rounded corners.

According to one embodiment, each of the parts 501 504 define a portion of a ring such that the body 500 is annular, whereby a ring capacitor, such as in FIG 5 shown is formed.

With further reference to FIG 5 can the parts 501 - 504 around the axial direction 110 be distributed. The parts 501-504 extend in a plane intersecting the axial direction 110. In particular shows 5 that the parts 501 - 504 are arranged in a plane perpendicular to the axial direction 110 runs.

Although in the in 5 shown four parts 501-504 the capacitor unit 500 It is understood that the capacitor unit 500 can be divided into a different number of parts. The capacitor unit 500 may be divided into at least two parts, so that at least a part of the capacitor unit is separable. By separable is meant that the part can be separated from the condenser unit without having to disassemble the entire condenser unit, that is, without having to separate all other parts. The separable part 504 is removable from the condenser unit 500 and can be placed back in position again.

Although in 5 only one of the parts 501 - 504 is shown separated from the condenser unit 500, that is, the part designated 504 in the present example, it will be understood that all of the parts 501 - 504 from the condenser unit 500 can be separable.

In general, at least one of the parts may, for example, be a separable portion of the body. As a result, at least one part can be removed and replaced individually without disturbing the surrounding parts of the body. This also improves the accessibility of the internal space (or inner space) bounded by the body (or the condenser unit) of the power converter cell, whereby electronic components (such as semiconductor switching devices) can be arranged in the interior space. By removing a portion of the capacitive body, any components in the interior can be inspected, removed, and possibly replaced or repaired. Such an embodiment of the body of the power converter cell facilitates maintenance and reduces the space required for maintenance, which in turn can lead to a more compact converter station. It understands In fact, in some embodiments, each of the parts of the body may be separable (that is, form separable portions of the body).

With reference to 6 Capacitor units are described according to some embodiments.

6 shows a schematic plan view of two different capacitor units 500 and 600 according to some embodiments.

6A shows a plan view of a capacitor unit 500 referring to 5 described capacitor unit 500 may correspond. In particular, the capacitor unit contains 500 a capacitive body that is an area or interior 570 , which is a square, can limit. By interior is meant the space or area that is in the through the parts 501 - 504 formed body defined closed loop. In other words, the interior 570 corresponds to the middle part of the condenser unit 500 ,

6B FIG. 12 also shows a plan view of another capacitor unit 600, which is described with reference to FIG 5 except that the area or inner space 670 defined by the capacitive body of the capacitor unit 600 is circular. The condenser unit 600 also includes three parts 601 - 603 solely for the formation of the capacitive body. Although the 6A and 6B show two examples of possible shapes of defined by the hollow body of two capacitor units interiors, other shapes may be considered. For example, the interior may also be elliptical or rectangular.

6B further shows that the body of the condenser unit 600 (and thereby the resulting power converter cell, after a switching device is disposed in the condenser unit) is between an outer diameter 660 and an inner diameter 662 extends.

7 shows a schematic view of a portion of a capacitor unit according to an embodiment.

7 shows an enlarged view of a part 700 a capacitor unit, such as that with reference to FIG 5 described capacitor unit 500 , The part 700 therefore can be any of the parts 501 - 504 correspond.

7 shows a part 700 which has the shape of a trapezoidal block with a curved surface 746 having. In particular, the part comprises 700 a first surface 746 defining a portion of the outer surface of the hollow body and a second surface 742 defining a portion of the interior defined by the hollow body. The part 700 further comprises two side surfaces 744, 748 which, when mounted in a condenser unit, are intended to be in contact with (or near) an adjacent part. The part also includes a base area 752 (or a lower surface) and an upper surface 750 ,

In the part 700 The two side surfaces form walls that extend into the first (curved) surface 746 extending cutting planes, forming a part of the outside of the condenser unit at an angle of less than 90 degrees. The two side surfaces are through the one part of the interior of the condenser unit 700 forming second surface 742 connected with each other. The base area 752 and the upper surface 750 extend into the two side surfaces and the first and second surfaces perpendicularly intersecting planes. The surfaces of the part form a closed box, in which an insulating material or in which a plurality of capacitive sub-elements can be arranged to the capacitive functionality of the part 700 to ensure.

Although 7 shows a part with a trapezoidal shape, it is understood that other geometries may be considered. For example, the two side surfaces 744 and 748 may intersect the first surface and the second surface perpendicularly, resulting in a cubic portion and a cubic portion of the capacitor unit, respectively. Further, the second surface defining a portion of the interior of the condenser unit may be curved, thereby providing a more circular interior rather than a square interior as defined by the present invention 7 is shown part is defined.

Further shows 7 that part 700 includes electrical connectors 760 disposed on the second surface 742 defining a portion of the interior of the capacitor unit. In other words, the electrical connectors are disposed on the wall facing the body defined by the body. The electrical connectors 760 may be used for connection to at least one switching device or a power converter circuit arrangement, which is arranged in the hollow center of the capacitor unit.

Generally, the parts of a condenser unit, such as the one in FIG 7 shown part 700 , a housing or a container in which at least one capacitor element can be arranged. The capacitor element may include metal plates and a dielectric material disposed between the metal plates. The capacitor element For example, it may be a wrap-foil capacitor. The housing or container defined by the part may be made of an electrically conductive material, such as metal, but may also be made of a non-conductive material. Depending on whether the housing is to be used for shielding, that is, depending on the application, the housing or the container may also be coated with a non-conductive paint. The mounting of the plurality of parts may yield a cylindrical capacitor.

8A shows a valve unit 1100 or at least a part thereof (the column of power converter cells with their inner support structure) in which a piece-wise capacitor unit (or a piecewise capacitive body) is used to form the power converter cells. It may be considered that 8A a part of a valve unit, such as that with reference to 9 described valve unit 1200 which is being assembled shows.

The valve unit 1100 contains a support structure 100 referring to 1 described support structure 100 may correspond. In 8A become a support structure 100 with two retaining plates 121 and 122 and four connectors as rods 141 - 144 shown.

The first holding plate 121 is arranged to receive a first power converter cell 131, while a second holding plates 122 is arranged to receive a second power converter cell 132. The first and second power converter cell 131 . 132 or the main bodies of these power converter cells may be any one of them with reference to FIGS 5 and 6 described body or power converter cells 500 and 600 correspond.

Although in the illustration only one power converter cell 131 is arranged on the first holding plate designated 151, can between the first holding plate 121 and the second holding plate 122 another power converter cell be used, so that the first holding plates 121 holds two power converter cells. The first holding plate has a through hole 151 on, can be made by the electrical connections between successive power converter cells.

8A also illustrates that the rods 141 - 144 within the through the parts of the bodies (or capacitor units) of the power converter cells 131 . 132 defined interior extend.

In the present configuration, the power converter cells and the holding plates do not need to be successively attached to the bars 141 - 144 to be attached. The holding structure can first be realized as a whole, that is by mounting the holding plates 121, 122 and the connecting elements 141 -144. The power converter cells may then be attached piecewise to the support structure, that is, by first mounting the four parts of the power converter cell together with their associated switching device and any other accessories, and then mounting another power converter cell.

In these embodiments, the intersection of a plurality of connecting elements with a holding element generally defines a plurality of compartments on the holding element that correspond to the number of parts of the body arranged on the holding element, wherein a part of the body is arranged in a compartment. The connecting elements, which extend between a first holding element and a second holding element, can be fixed to the first holding element between two adjacent parts of the body arranged on the first holding element. In such embodiments, there may be a certain gap between two adjacent parts of the body of the power converter cell, so that the connecting elements can be inserted or arranged between these two adjacent parts. In these embodiments, the connection elements are arranged in a space defined by the outer circumference of the power converter cell and an inner circumference of the power converter cell as defined by the mounting of the parts.

9 FIG. 12 shows a schematic view of a valve unit 1200 of a power converter, such as an HVDC power converter, in accordance with some embodiments.

The valve unit 1200 comprises a plurality of power converter cells 1271-1280, that is, in the present example, ten power converter cells, which by means of a holding structure 100 are arranged as a stack. The valve unit 1200 however, may include any number of power converter cells, depending on the application, and thus the desired voltage or power.

The valve unit 1200 may also include high voltage capacitor shields disposed between two adjacent (or sequential) power converter cells.

As shown in the enlarged view, part of the in 9 shown valve unit, a power converter cell 1275 in the valve unit 700 , a capacitor unit and a power converter circuit described with reference to any of 5 - 7 include described type. In the 9 shown converter cells can condenser units with disc-shaped housings contain. Other shapes may also be considered, such as circular, elliptical or rectangular cross-section housings. In one embodiment, the capacitor units (and thereby the power converter cells) may take the form of rings surrounding the power converter circuits.

As already in 9 shown, the power converter circuits of the power converter cells 1271 For example, to be electrically connected in series to increase the input and / or output voltage of the valve unit 1200.

As in 9 As shown, the use of a power converter cell having a body divided into a plurality of parts is favorable because separation of one of the parts facilitates accessibility to other components of the power converter cells (that is, within the interior space defined by the capacitor unit of the power converter cell), thereby performing maintenance relieved and the space required is reduced.

8B shows a schematic view of a valve unit according to another embodiment.

8B shows a valve unit 1300 referring to 8A described valve unit 1100 matches, except that the connectors are offset. In 8B contains the support structure 1310 several fasteners 1341 - 1344 not within the interior space formed by the power converter cells of the stack 151 but extend between the outer diameter of the designated 1331 power converter cell and its inner diameter. Similarly, the fasteners extend 1341 - 1344 between the outside diameter of the 1332 power converter cell and its inside diameter. Between adjacent parts of a power converter cell, a gap may be provided, so that the connecting elements to the holding plates 121 . 122 can be fixed. In these embodiments, the connecting elements 1341 - 1344 arranged between two juxtaposed parts.

With reference to 10 becomes a valve unit 1400 described according to one embodiment.

10 10 shows a cross-sectional view of a valve unit 1400 comprising a container (or housing) 280 and a plurality of cells formed using a support structure comprising a plurality of rods 141 - 143 and holding elements 121 - 124 as with reference to the 1 and 2 described as containing a stack in the housing 280 are arranged.

In the 10 shown valve unit 1400 can the referring to 2 described valve unit 200, except that they also have a first connector 1460 for connecting one end of the stack of the valve unit to another valve unit and a second connector 1470 for connecting another end of the stack of the valve unit with yet another valve unit.

The container 280 containing the stack of power converter cells may be closed or sealed. For example, a spacer may be disposed on one of the ends or base surfaces of the housing. As in 10 As shown, a first spacer 1416 may be at one end 288 of the container 280, while a second spacer element 1414 at an opposite end 289 of the container 280 can be arranged. In particular, the first spacer element 1416 at the junction between the first connector 1460 and the upper end 288 of the container 280 be arranged while the second spacer element 1414 at the junction between the second connector 1470 and the lower end 289 of the container 280 can be arranged.

The first spacer element 1416 and the second spacer 1414 may be made of, for example, an insulating material.

There may be a spacer element at one end of the container for separating the container from a container of another valve unit to which the valve unit is connected.

The first connector 1460 includes a busbar member 1461 adapted to connect the stack of power converter cells (and in particular an upper cell of the stack) to the stack of an adjacent valve unit (in FIG 10 not shown) is arranged. The first connector 1460 may include a bus bar element made of a single piece bent to connect two cells located on top of the stacks of two adjacent valve units. As in 10 shown, the busbar element of the first connector 1460 as an alternative, contain multiple segments. For example, the first connector may be a node element 1462 for connecting a first segment of the busbar element to another segment of the busbar element extending along the axial direction 110 extends, in order to connect the power converter cells in series. At the in 10 The particular embodiment shown is Node member 1462 configured to a segment of the busbar element 1461 in an axial direction 110, along which the container 280 extends to guide a cutting direction (for example, orthogonal thereto) to reach an adjacent valve unit.

The second connector 1470 includes a busbar member 1471 adapted to connect the stack of power converter cells (and more particularly a lower cell of the stack) to the stack of an adjacent valve unit (in FIG 1 not shown) is arranged. The second connector 1470 may include a bus bar member made of a single piece bent to connect two cells located at the bottom of the stack of two adjacent valve units. As in 10 shown, the busbar element of the second connector 1470 as an alternative, contain multiple segments. For example, the second connector may be a node element 1472 for connecting a first segment of the busbar element to another segment of the busbar element extending along the axial direction 110 extends, in order to connect the power converter cells in series. At the in 1 In the particular embodiment shown, the node member 1472 is configured to include a segment of the busbar member 1471 in an axial direction 110, along which the container 2801 extends to guide a cutting direction (for example, orthogonal thereto) to reach an adjacent valve unit.

The first connector 1460 and the second connector 1470 may be configured to guide a bus bar element in opposite directions to reach the stack of two different valve units, thereby enabling series connection of the valve units to form a larger power converter.

At the in 10 In the embodiment shown, the stack of cells and its support structure may be inserted into or removed from the housing 280 by the first spacer or spacer 1416 , the first connector 1460 at the top end of the cylinder-like container 280 is attached, removed, causing the container 280 is opened, and in which optionally the second spacer element 1414 is removed and an upper part of the container 280 is dismantled.

The valve unit 1400 Optionally also with an upper (or first) capacitor shield 1411 at the upper end 288 of the container 280 and a lower (or second) capacitor shield 1413 at the bottom 289 of the container 280 be provided, on which the support structure (and in particular the rods 141 - 143 ) to support the stack of power converter cells. The electrical shields 1411 and 1413 may be removable parts of the container to facilitate insertion of the column of power converter cells into the container.

More generally, the valve unit may be connected to another valve via its first connector or may be connected to an AC or DC transmission line via a pluggable cable termination. For example, the first connector may include a first busbar element for electrically connecting the subject cell to a cell of another valve unit. The first connector may, for example, be arranged to electrically connect an upper cell of the pillar of a first valve unit to an upper cell of a pillar of a second valve unit. The first connector may be insulated by an electrically insulating gas.

As in the example of 10 It is obvious that a valve unit at another end of the container may be equipped with a second connector for connecting another cell of the column to another valve unit. According to some embodiments, the first connector and the second connector may be located at opposite ends of the container. In particular, the first connector may be configured to electrically connect an upper cell of the column (for example, located on top of the stack) to an upper cell of one pillar of the other valve unit. Similarly, the second connector may be configured to electrically connect a lower cell of the column to a lower cell of the column (for example, the lowest one in the valve stack) of a third valve unit. For example, in the case of a cylinder-like receptacle (or housing), the first connector may be disposed on a first base of the cylinder-like receptacle, and the second connector may be disposed on a second base of the cylindrically-shaped receptacle opposite the first base.

It is understood that the valve unit may further or alternatively be provided with a plug-in cable termination or gas-insulated busbar for connection to an AC transmission line. Likewise, the valve unit may be equipped with another pluggable cable termination or gas-insulated busbar for connection to a DC transmission line. Whether the valve unit is equipped with one or more connectors or a pluggable cable termination (or gas-insulated busbar) depends on the position of the valve unit in question Arrangement of several valve units, which are used for the construction of a converter station off. In a configuration with only two valve units, the first valve unit may include a plug-in cable termination or gas-insulated bus bar for connection to an AC transmission line at one end of its container, while the first valve unit at its opposite end via a first electrically isolated by gas first connector second valve unit is connected. A cell at an opposite end of the second valve unit may be connected to a DC transmission line via a pluggable cable termination or gas-insulated busbar.

With reference to 11 becomes a valve unit 1500 described according to yet another embodiment.

The valve unit 1500 contains a container 1580 that contains at least four main parts. The container 1580 may be cylindrical, and its middle part may consist of two tubular parts 1582 and 1583 , which may include flanges for mounting these two parts, be made. The container 1580 may also include two end parts, which may be shaped as bottle necks. A container made of several parts can facilitate the assembly of the valve unit and in particular the insertion of the power converter cells and the support structure into the container.

As in 11 shown, the valve unit can 1500 a support structure containing several retaining elements 1520 contains (although in 15 only one is shown so as not to obscure the figure too much), and a plurality of connecting members (or rods) 1540 connecting the holding members (or holding plates) to each other. The connecting elements 1540 are within the outer periphery of the holding member 1520 arranged power converter cell 1530 arranged.

According to one embodiment, a converter station is provided. The converter station may comprise at least two valve units as defined in any one of the preceding embodiments. The converter station may also be referred to as a high voltage direct current (HVDC) converter station.

Furthermore, it is understood that the plurality of power converter cells of the valve unit can only form part of a larger power converter. In particular, according to some embodiments, a power converter arm (or a power branch) may comprise at least two valve units as defined in any one of the preceding embodiments. In these embodiments, the power converter cells of a first valve unit may be electrically connected in series with the power converter cells of a second valve unit, as described above.

The HVDC converter station may also be constructed by mounting at least two valve arms, with one arm including a plurality of valve units connected electrically in series. For example, the HVDC converter station may include three arms for providing a three-phase converter.

As mentioned above, the outer surface of the container may contain an electrically conductive material or an electrically conductive layer, such as a metal, which may then be used for grounding. In a valve arm or in a converter station, all of the containers of the valve units may contain a metal (or an electrically conductive outer surface) with electrical potential to ground.

The present disclosure is applicable to power supplies having various voltage levels, such as a high voltage power converter station, but also medium voltage devices where space management is to be improved. The embodiments of the present disclosure are advantageous in any applications where a column of power converter cells is used. By way of example only, embodiments of the present disclosure may be made to obtain power converters such as a static static synchronous compensator for flexible AC transmission system (FACTS) applications, motor drives, subsea converters, and DC / DC converters a direct current network, be cheap. However, other applications may also be considered. The embodiments of the present disclosure improve the space management by means of gas insulation in the container and by arranging the support structure within the outer diameter of the column of power converter cells, that is, via an inner support structure.

The present disclosure is generally advantageous for applications where a more compact power supply device is desired, such as in applications where space for the installation of the electrical power unit is limited and / or for offshore wind farm applications.

In the context of the present disclosure, the term valve unit can be exchanged for the terms power converter valve stack, block unit or device (of a power converter).

Although features and elements are described above in certain combinations, each feature or element may be used without the other features and elements or in various combinations with or without other features and elements alone. Although the in the 4 and 6 In particular, while examples shown include five valve units, it is to be understood that any other number of valve units may be used to form a converter station (or at least a portion thereof). Further, a reference to a first, second, third, fourth and fifth valve unit may be interchanged, for example, the third valve unit may be considered as the first valve unit and vice versa.

Moreover, variants of the disclosed embodiments may be understood and practiced by the skilled practitioner of the claimed invention from a thorough examination of the drawings, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other elements, and the indefinite article "a" or "a" does not exclude a plurality. The very fact that certain features are cited in different dependent claims does not indicate that a combination of these features can not be used to advantage.

Claims (21)

Valve unit comprising: a container that is at least partially filled with an electrically insulating gas and extends along an axial direction; a plurality of power converter cells, which are arranged as at least one column in the container; a plurality of holding elements, wherein a holding element is arranged to hold at least one power converter cell; and a plurality of connecting elements mechanically connecting the holding elements, wherein the connecting elements extend from a first holding element to another within a limited by an outer circumference of a arranged between the holding elements power converter cell space. Valve unit after Claim 1 wherein the column is arranged by power converter cells coaxial with the axial direction along which the container extends. Valve unit after Claim 1 or 2 wherein the container has a cylindrical shape. Valve unit according to one of the preceding claims, wherein the holding elements and the connecting elements together form a support structure for the power converter cells. Valve unit according to one of the preceding claims, wherein the holding elements define a plurality of locations for the arrangement of the power converter cells along the axial direction, wherein a first location at or near a first extremity of the container and a second location at or near an outermost end of the container located at the first extreme end along the axial direction. Valve unit according to one of the preceding claims, further comprising at least one attachment member for attaching at least one of the holding elements and / or the connecting elements to a lower surface, an upper surface and / or a wall surface of the container. Valve unit according to one of the preceding claims, wherein at least a part of a holding element is integrated in a body of the supported by the holding element power converter cell. A valve unit according to any one of the preceding claims, wherein a power converter cell includes a body extending in a radial direction between an outer periphery and an inner periphery, thereby defining an inner space. Valve unit after Claim 6 , wherein the connecting elements extend within the interior. Valve unit after Claim 6 or 7 wherein the body is divided into several parts, one part forming a portion of the body. Valve unit after Claim 6 - 8th wherein a holding member includes a middle through-hole having a circumference corresponding to or larger than the inner circumference of the body of a power converter cell arranged on the holding member. Valve unit according to one of the preceding claims, wherein an outer surface of a power converter cell may be elliptical, circular and / or at least comprise a rounded corner. Valve unit according to one of the preceding claims, wherein the power converter cell may comprise at least one capacitor element, which is arranged in a body extending from the outer periphery to an inner periphery of the power converter cell, and at least one switching device. Valve unit after Claim 8 wherein the point of intersection of the plurality of connecting elements with a holding element defines a plurality of compartments on the holding element, that of the number of parts of the body arranged on the holding element correspond, wherein a part of the body is arranged in a compartment. Valve unit according to one of the preceding claims, further comprising a first electrical shield for inserting the at least one column of power converter cells at one end of the container and / or an electrical shield for inserting the stack of power converter cells at an opposite end of the container. The valve assembly of any one of the preceding claims, further comprising at least one connector including a first busbar member that electrically connects a cell of the valve assembly at one end of the container to a cell of a second valve assembly. Valve unit according to one of the preceding claims, further comprising a spacer element, which contains insulating material and at one end of the container for spacing the container from a container of another valve unit, with which the valve unit is connected, is arranged. Valve unit according to one of the preceding claims, wherein the insulating gas is sulfur hexafluoride (SF ₆ ) and / or nitrogen (N ₂ ) and / or air and / or dry air. Valve unit according to one of the preceding claims, wherein a connecting element at least partially contains solid insulating material. Valve unit according to one of the preceding claims, wherein the axial direction is vertical, so that the container is vertically aligned from the ground. Converter station comprising at least two valve units as defined in any one of the preceding claims.

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