WO2018133914A1

WO2018133914A1 - High voltage valve arrangement and method

Info

Publication number: WO2018133914A1
Application number: PCT/EP2017/050836
Authority: WO
Inventors: Björn SANDIN; Jennie KAPELL; Johannes GRAN-HIRVIOJA
Original assignee: Abb Schweiz Ag
Priority date: 2017-01-17
Filing date: 2017-01-17
Publication date: 2018-07-26

Abstract

High voltage valve arrangement (10) comprising a high voltage valve structure (12); and a support structure (14) constituted by a plurality of post insulators (32) for supporting the valve structure (12) on a support surface (18); wherein the post insulators (32) are inclined with respect to a vertical axis (26).

Description

HIGH VOLTAGE VALVE ARRANGEMENT AND METHOD

Technical Field

The present disclosure generally relates to a high voltage valve arrangement. In particular, a high voltage valve arrangement comprising a support structure constituted by tilted post insulators and a method of providing support for a high voltage valve arrangement are provided.

Background

In valve halls where high voltage semiconductor valves are arranged, the valve structures may be arranged as hanging valve structures or standing valve structures. Hanging valve structures are typically mounted suspended from the ceiling of the valve hall. Standing valve structures are typically supported on the valve hall floor by means of a plurality of vertically aligned post insulators and cross bracings are often used to strengthen the support by reducing torque loads on the post insulators.

CN 104852603 A describes a multi-level voltage source current converter valve tower. The tower is supported by a support structure comprising a plurality of vertical insulators. Cross bracings are arranged between the vertical insulators. Summary

The support structure in CN 104852603 A is complicated to install and expensive due to the need for cross bracings. The cross bracings also block access to the area below the tower, e.g. for maintenance.

One object of the present disclosure is to provide a simple and strong support structure for a high voltage valve arrangement. A further object of the present disclosure is to provide a support structure for a high voltage valve arrangement that reduces the load requirements on the post insulators.

A still further object of the present disclosure is to provide a high voltage valve arrangement that simplifies maintenance activities.

A still further object of the present disclosure is to provide a cheap support structure for a high voltage valve arrangement.

A still further object of the present disclosure is to provide a method of providing a simple and strong support for a high voltage valve structure on a support surface.

A still further object of the present disclosure is to provide a simple method of providing a support for a high voltage valve structure on a support surface.

According to one aspect, there is provided a high voltage valve arrangement comprising a high voltage valve structure and

a support structure constituted by a plurality of post insulators for supporting the valve structure on a support surface, wherein the post insulators are inclined with respect to a vertical axis.

The support structure of the valve arrangement only comprises (i.e. consists of) the inclined or tilted post insulators. In other words, the support structure does not comprise any vertical support elements. Furthermore, the support structure does not comprise any strengthening supports such as cross bracings. Therefore, the valve arrangement requires fewer components. The support structure is merely constituted by the inclined post insulators and optionally interface components of each post insulator to the valve structure and/or the support surface.

By arranging the post insulators inclined with respect to the vertical axis, the load demands on the post insulators are reduced which eliminates the need for cross bracings. For example, the inclination of the post insulators can better withstand horizontal force components acting on the valve structure. Thereby, the arrangement is made simpler and cheaper and can still meet the force requirements on the valve arrangement, e.g. seismic requirements. As a further consequence, the arrangement is made more accessible for

maintenance activities. Moreover, the valve arrangement does not need to use active dampers.

A high voltage within the present disclosure may be a voltage of at least 6 kV. Thus, a high voltage valve arrangement or system according to the present disclosure may have a system voltage of at least 6 kV.

The high voltage valve structure according to the present disclosure may for example be constituted by a high voltage direct current (HVDC)

semiconductor valve structure. The valve structure may comprise at least two valve layers. Each valve layer may in turn comprise one or more valve modules. An electric shield structure comprising a plurality of electric shields, such as corona shields, may be arranged around the valve layers of the valve structure in order to lower the electrical fields to minimize the risk for partial discharge and/or flashover .

The post insulators may be inclined at least 5⁰, such as at least io°, with respect to the vertical axis. According to one variant, the post insulators are inclined 5⁰ to 15⁰ with respect to the vertical axis. Each post insulator may or may not have the same inclination with respect to the vertical axis. A post insulator according to the present disclosure may alternatively be referred to as an insulated rod, insulated bar, insulated column or insulated strut. The post insulators have an elongated appearance and may be substantially straight. The valve structure may comprise a lower face or lower side facing the support surface and all post insulators may be arranged horizontally outside a central major portion of the lower side such that a free space is formed between the lower side and the support surface. The central major portion of the lower side may be continuous and may constitute at least 90 % of the total area (in a horizontal plane) of the lower side. The lower side of the valve structure may be constituted by a frame of a plurality of planar support beams.

Each post insulator may be connected to a valve structure connection point on the valve structure and to a support surface connection point on the support surface such that a support surface connection area formed by the support surface connection points is larger than a valve structure connection area formed by the valve structure connection points. The support surface connection area may for example be at least 10 %, such as at least 20 %, such as at least 30 % larger than the valve structure connection area. Each of the support surface connection area and the valve structure connection area may adopt a generally rectangular, square, polygonal or circular shape.

Each post insulator may be connected to a unique valve structure connection point and to a unique support surface connection point. As an alternative, two or more post insulators may share a common valve structure connection point and/or a common support surface connection point.

In each of the above cases, the post insulators may be arranged such that the longitudinal axes of some or all post insulators intersect at a crossing point. If not all longitudinal axes of the post insulators intersect at a common crossing point, some or all longitudinal axes of the post insulators may cross a common imaginary crossing line, e.g. a horizontal line.

The crossing point may be positioned vertically above the center of gravity of the valve structure. For example, the crossing point may be positioned at twice the height of the center of gravity. Alternatively, or in addition, the crossing point may be vertically above the geometrical center of the valve structure. The same applies for the crossing line.

The crossing point and the center of gravity of the valve structure may be arranged along the vertical axis. Alternatively, the crossing point may be horizontally offset with respect to the vertical axis through the center of gravity, e.g. when the inclinations of the respective post insulator differ. The valve structure may have a substantially rectangular or square cross section and one post insulator may be associated with each corner of the valve structure. According to one variant, the cross section of the valve structure is substantially square. Alternatively, the valve structure may have another polygonal cross section (e.g. triangular) or a substantially circular cross section. In the case of a polygonal cross section, one or more post insulators may be associated with each corner and/or side of the cross section. In the case of a substantially circular cross section, the post insulators may be substantially evenly distributed around the circumference of the valve structure.

As some non-limiting examples, the support structure may be constituted by four post insulators (e.g. one on each bottom corner or two on two opposite sides of a bottom of a valve structure with a rectangular cross section, or evenly distributed around a bottom of a valve structure with a cross section having a substantially circular appearance), six post insulators (e.g. three on two opposite sides of a bottom of a valve structure with a rectangular cross section), eight post insulators (e.g. one on each bottom corner and one on each side, two on each side, or four on two opposite sides, of a bottom of a valve structure with a rectangular cross section, or evenly distributed around a bottom of a valve structure with a cross section having a substantially circular appearance).

The high voltage valve arrangement according to the present disclosure may comprise a suspending structure, in addition to the support structure. The suspending structure can be arranged to carry a part of the gravity load of the valve structure, e.g. by means of a plurality of suspending insulators attached to a valve hall ceiling or similar. However, according to a preferred variant, the valve structure is a standing valve structure such that the entire gravity load of the valve structure is transferred to the support surface by the post insulators. The support surface may be constituted by a valve hall floor. However, in case the high voltage valve arrangement is arranged in a valve hall, the support surface may or may not be constituted by a valve hall floor. The support surface may for example be constituted by a part of a valve carrying scaffold. The support surface may be planar. In addition, the support surface may be horizontal or substantially horizontal. According to a further aspect, there is provided a method of providing support for a high voltage valve structure on a support surface, the method comprising providing a valve structure, providing a support structure constituted by a plurality of post insulators, and arranging the post insulators inclined with respect to a vertical axis to support the valve structure on a support surface. The method may further comprise the steps of providing a temporary support vertically below the valve structure before arranging the post insulators and removing the temporary support when some or all of the post insulators have been arranged to support the valve structure on the support surface. As used herein, a substantially perpendicular/parallel relationship includes a perfectly perpendicular/parallel relationship as well as deviations from a perfectly perpendicular/parallel relationship with up to 5 %, such as up to 2 %. Furthermore, a vertical direction as used herein refers to a direction aligned with the direction of the force of gravity and a horizontal direction refers to a direction perpendicular to the vertical direction.

Brief Description of the Drawings

Further details, advantages and aspects of the present disclosure will become apparent from the following embodiments taken in conjunction with the drawings, wherein: Fig. 1: schematically represents a side view of a high voltage valve

arrangement comprising a high voltage valve structure and a support structure;

Fig. 2: schematically represents a top view of the high voltage valve

arrangement in Fig. 1; and Fig. 3: schematically represents a top view of a further high voltage valve arrangement.

Detailed Description

In the following, a high voltage valve arrangement comprising a support structure constituted by tilted post insulators and a method of providing support for a high voltage valve arrangement will be described. The same reference numerals will be used to denote the same or similar structural features.

Fig. 1 schematically represents a side view of a high voltage valve

arrangement 10 comprising a high voltage valve structure 12 and a support structure 14. The valve arrangement 10 of this example is arranged in a valve hall having a ceiling 16 and a support surface 18 constituted by a horizontal and planar valve hall floor. Fig. 1 further denotes a vertical direction 20 and a first horizontal direction 22. The valve structure 12 may be a HVDC semiconductor valve structure and comprises a plurality of valve layers 24 (four in Fig. 1). The valve layers 24 are arranged vertically on top of each other and are substantially aligned along a vertical axis 26. Insulators 28 are arranged between each pair of adjacent valve layers 24. The valve structure 12 further comprises an electric shield structure comprising a plurality of electric shields 30 in order to lower the electrical fields. Each electric shield 30 is associated with, and arranged around, a valve layer 24. The electric shields 30 may be constituted by corona shields.

The valve structure 12 in Fig. 1 is a standing valve structure. The support structure 14 is constituted by a plurality of post insulators 32. In the example of Fig. 1, the support structure 14 comprises four post insulators 32 (only two are shown). The post insulators 32 are the only constituents of the support structure 14. In particular, the support structure 14 does not comprise any vertical support elements or cross bracings. Thus, the valve structure 12 is only supported by the post insulators 32 of the support structure 14 and the entire load of the valve structure 12 transferred to the support surface 18 via the tilted post insulators 32. A free space 34 is formed between a lower side 36 of the valve structure 12 and the support surface 18. As can be seen in Fig. 1, the post insulators 32 are inclined with respect to the vertical axis 26. The inclination is here exemplified as approximately io° for each post insulator 32 with respect to the vertical axis 26.

The post insulators 32 each has an elongated appearance forming a longitudinal axis 38. In Fig. 1, the post insulators 32 are arranged such that the longitudinal axes 38 of all post insulators 32 intersect at an imaginary crossing point 40. The crossing point 40 is positioned vertically above the center of gravity 42 of the valve structure 12 along the vertical axis 26. In Fig. 1, the crossing point 40 is positioned at approximately twice the height of the center of gravity 42, as measured from the support surface 18. The center of gravity 42 of the valve structure 12 according to this example coincides with a geometrical center (not denoted) of the valve structure 12.

In Fig. 1, each post insulator 32 comprises two interface components in the form of a valve structure coupling member 44 and a support surface coupling member 46. Each valve structure coupling member 44 creates an interface between the angled post insulator 32 and the lower side 36 of the valve structure 12 at a valve structure connection point 48. Each support surface coupling member 46 creates an interface between the angled post insulator 32 and the support surface 18 at a support surface connection point 50.

The continuous free space 34 below the valve structure 12 is advantageous since it provides a facilitated access to the valve structure 12, e.g. for maintenance activities. Moreover, when installing the valve arrangement 10, a temporary support (not shown) can be positioned below the valve structure 12 to carry the load of the valve structure 12 when connecting some or all of the post insulators 32. The temporary support may be removed from the free space 34 when the post insulators 32 have been installed. Furthermore, since the post insulators 32 are tilted with respect to the vertical axis 26, the torque loads acting on the interface components are reduced . As a consequence, the need for strengthening supports, such as cross bracings, can be eliminated and the access to the valve structure 12 is further improved.

Fig. 2 schematically represents a top view of the high voltage valve

arrangement 10 in Fig. 1. In addition to the first horizontal direction 22 shown in Fig. 1, Fig. 2 also shows a second horizontal direction 52, perpendicular to the first horizontal direction 22. As can be seen in Fig. 2, each valve layer 24 comprises two valve modules 54. The valve modules 54 are substantially symmetrically arranged with respect to the center of gravity 42 in a horizontal plane. The valve structure 12 of this example has a substantially square cross section and a post insulator 32 is attached to each corner of the valve structure 12. Thus, each post insulator 32 is connected to a unique valve structure connection point 48 and to a unique support surface connection point 50.

Fig. 2 further shows that the valve structure connection points 48 form a square shaped valve structure connection area 56 and that the support surface connection points 50 form a support surface connection area 58. The valve structure connection area 56 and the support surface connection area 58 are formed by outer imaginary lines drawn between the valve structure connection points 48 and the support surface connection points 50, respectively.

The valve structure connection area 56 constitutes a central major portion of the lower side 36 of the valve structure 12. As can be seen in Fig. 2, none of the post insulators 32 is arranged inside the valve structure connection area 56.

In the example of Fig. 2, both the valve structure connection area 56 and the support surface connection area 58 are substantially square. However, depending on the implementation, the valve structure connection area 56 and the support surface connection area 58 may adopt alternative shapes, such as substantially circular shapes, alternative polygonal shapes or irregular shapes.

The support surface connection area 58 is larger than the valve structure connection area 56. In the example of Fig. 2, the support surface connection area 58 is approximately 30 % larger than the valve structure connection area 56. Thereby, also the free space 34 formed between the lower side 36 of the valve structure 12 and the support surface 18 and inside the post insulators 32 is enlarged in comparison with a prior art support structure comprising vertical post insulators (and typically also cross bracings blocking access to the space, if any, below the valve structure).

Fig. 3 schematically represents a top view of a further high voltage valve arrangement 10. Mainly differences with respect to Figs. 1 and 2 will be described. Also the valve structure 12 in Fig. 3 has a substantially square cross section. However, in this example, the support structure 14 is constituted by eight post insulators 32a-32h. Two post insulators 32 are attached to each side of the valve structure 12.

The longitudinal axes 38a, 38b of the two post insulators 32a, 32b on the upper side in Fig. 3 and the longitudinal axes 38ε, 38f of the two post insulators 32ε, 32f on the lower side in Fig. 3 intersect a common imaginary crossing line 60. In this example, the crossing line 60 is horizontal and parallel with the first horizontal direction 22.

Correspondingly, the longitudinal axes 38c, 38d of the two post insulators 32c, 32d on the right side in Fig. 3 and the longitudinal axes 38g, 38I1 of the two post insulators 32g, 32I1 on the left side in Fig. 3 intersect a common imaginary crossing line 62. In this example, the crossing line 62 is horizontal and parallel with the second horizontal direction 52. Several crossing points 4oa-h are also formed in Fig. 3: the longitudinal axes 38a, 38I1 intersect at a crossing point 40a, the longitudinal axes 38b, 38c intersect at a crossing point 40b, the longitudinal axes 38d, 38ε intersect at a crossing point 40c, the longitudinal axes 38f, 38g intersect at a crossing point 4od, the longitudinal axes 38c, 38I1 intersect at a crossing point 4oe, the longitudinal axes 38b, 38ε intersect at a crossing point 4of, the longitudinal axes 38d, 38g intersect at a crossing point 40g, and the longitudinal axes 38a, 38f intersect at a crossing point 40I1. Each crossing point 40a-h is positioned vertically above the center of gravity 42 of the valve structure 12. The crossing points 4oe, 4of, 40g, 40I1 are positioned vertically above the crossing points 40a, 40b, 40c, 4od.

While the present disclosure has been described with reference to exemplary embodiments, it will be appreciated that the present invention is not limited to what has been described above. For example, it will be appreciated that the dimensions of the parts may be varied as needed. Accordingly, it is intended that the present invention may be limited only by the scope of the claims appended hereto.

Claims

High voltage valve arrangement (10) comprising:

- a high voltage valve structure (12); and

- a support structure (14) constituted by a plurality of post insulators (32) for supporting the valve structure (12) on a support surface (18); wherein the post insulators (32) are inclined with respect to a vertical axis (26).

The high voltage valve arrangement (10) according to claim 1, wherein the post insulators (32) are inclined at least 5⁰, such as at least io°, with respect to the vertical axis (26).

The high voltage valve arrangement (10) according to claim 1 or 2, wherein the valve structure (12) comprises a lower side (36) facing the support surface (18) and wherein all post insulators (32) are arranged horizontally outside a central major portion of the lower side (36) such that a free space (34) is formed between the lower side (36) and the support surface (18).

The high voltage valve arrangement (10) according to any of the preceding claims, wherein each post insulator (32) is connected to a valve structure connection point (48) on the valve structure (12) and to a support surface connection point (50) on the support surface (18) such that a support surface connection area (58) formed by the support surface connection points (50) is larger than a valve structure connection area (56) formed by the valve structure connection points (48).

The high voltage valve arrangement (10) according to claim 4, wherein the support surface connection area (58) is at least 10 % larger than the valve structure connection area (56).

6. The high voltage valve arrangement (10) according to claim 4 or 5, wherein each post insulator (32) is connected to a unique valve structure connection point (48) and to a unique support surface connection point (50).

7. The high voltage valve arrangement (10) according to any of the

preceding claims, wherein the post insulators (32) are arranged such that the longitudinal axes (38) of some or all post insulators (32) intersect at a crossing point (40).

8. The high voltage valve arrangement (10) according to claim 7, wherein the crossing point (40) is positioned vertically above the center of gravity (42) of the valve structure (12).

9. The high voltage valve arrangement (10) according to claim 8, wherein the crossing point (40) and the center of gravity (42) of the valve structure (12) are arranged along the vertical axis (26).

10. The high voltage valve arrangement (10) according to any of the

preceding claims, wherein the valve structure (12) has a substantially rectangular or square cross section, wherein the support structure (14) comprises four post insulators (32) and wherein one post insulator (32) is associated with each corner of the valve structure (12).

11. The high voltage valve arrangement (10) according to any of the

preceding claims, wherein the support structure (14) is constituted by four post insulators (32).

12. The high voltage valve arrangement (10) according to any of the

preceding claims, wherein the valve structure (12) is a standing valve structure (12) such that the entire gravity load of the valve structure (12) is transferred to the support surface (18) by the post insulators (32).

13. The high voltage valve arrangement (10) according to any of the

preceding claims, wherein the support surface (18) is constituted by a valve hall floor.

14. Method of providing support for a high voltage valve structure (12) on a support surface (18), the method comprising:

- providing a valve structure (12);

- providing a support structure (14) constituted by a plurality of post insulators (32); and

- arranging the post insulators (32) inclined with respect to a vertical axis (26) to support the valve structure (12) on a support surface (18).

15. The method according to claim 14, further comprising:

- providing a temporary support vertically below the valve structure (12) before arranging the post insulators (32); and

- removing the temporary support when some or all of the post insulators (32) have been arranged to support the valve structure (12) on the support surface (18).