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Title:
THREE-PHASE SELECTOR FOR ON-LOAD TAP CHANGER WITH INSULATED PHASES
Document Type and Number:
WIPO Patent Application WO/2018/148810
Kind Code:
A1
Abstract:
The selector comprises an upper mange (11) and a lower flange (12) connected to insulating segments (13) cut-out of an insulating cylinder. The three phases (A, B, C) are located in tiers, where on the segments (13, 16) are mounted an (14) and odd (15) stationary contact elements. There is also a wide insulating segment (16), located next to not shown preselector. In the middle of this segment are mounted the largest in number fixed contact elements. The tapping contact elements (44, 45) with arms (47) are mounted on both sides of the insulating segment (16) on which are located contact plates (48). In the centre of the selector are mounted an even driving insulating segment (25) and an odd driving isolating segment (30) between the upper flange (11) and the lower flange (12). They are driven in ships by a certain Geneva gear, mounted on the upper flange.

Inventors:
GROZDANOV, Toni Dragomirov (1 "Kazebek" Str, entr.B ap.8, 1516 Sofia, BG)
NIKOLOV, Veselin Stefanov (Compl. "Nadezhda 3" bl. 306, entr. IV ap. 81, 1229 Sofia, BG)
VALILEV, Borislav Lyubenov (Distr. "Iliyantsi", 1 "Gergina" Str, 1271 Sofia, BG)
Application Number:
BG2018/000010
Publication Date:
August 23, 2018
Filing Date:
February 14, 2018
Export Citation:
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Assignee:
ABB BULGARIA EOOD (89B Vitosha Boulevrd BuildingA Floor 17, 1408 Sofia, 1408, BG)
International Classes:
H01H9/00; H01F29/04
Foreign References:
BG62748B12000-06-30
US20160133399A12016-05-12
GB1241232A1971-08-04
US20160012982A12016-01-14
Other References:
None
Attorney, Agent or Firm:
GEORGIEVA-TABAKOVA, Milena Lyubenova (18. "Ami Bue" Str, entr. V, 1606 Sofia, 1606, BG)
Download PDF:
Claims:
PATENT CLAIMS

1. Three-phase selector for an on-load tap changer with insulated phases, containing an upper flange with a double transfer element and two Geneva cross wheels and a lower flange, moreover several segments made of insulating material are mounted between the two flanges with even and odd fixed contact elements fixed thereon, in the centre of the selector there are even and odd driving insulating segments with, concentrically located thereon, even and odd current-carrying rings with arms, on one side of which current-carrying plates are mounted, connecting the rings electrically to the fixed contact elements, and radially on the rings there are tapping contact elements with arms carrying tapping contact plates making contact with the rings, characterized in that there is a wider insulating segment (16), on which, in addition to even and odd fixed contact elements (14, 15), even and odd tapping contact elements (44, 45) are mounted in two rows for the three phases (A, B, C), moreover these elements have arms (46, 47) with tapping contact plates (48, 49) rubbing on the rings (35, 40), and the rings (35, 40) have an edge (43), which makes contact with a stem (51) located at the end of the arm (45) and thus guarantees accurate interaction of the contact plates (48) with the rings (35, 40).

2. Three-phase selector for an on-load tap changer according to claim 1, characterized in that the wider insulating segment (16) is located beside a preselector, moreover the fixed even contact elements numbered last (A10, B10, CIO) are mounted in tiers in the middle thereof.

3. Three-phase selector for an on-load tap changer according to claims 1 and 2, characterized in that on one side of the fixed contact elements (A 10, B10, CIO) on segment (16), the tapping contact elements (AI, BII and BI) are fixed in tiers, and on the other side - the tapping contact elements (AH, C1I and CI), moreover these tapping contact elements are connected with two bundles of conductors to the fixed contact elements of the power diverter switch (ΑΪ, All, BI, BII, CI, CII)..

4. Three-phase selector for an on- load tap changer according to claims 1, 2 and 3, characterized in that the stem (51) located at the end of the arm (45) is replaced with a roller (52) 5. Three-phase selector for an on-ioad tap changer according to claims 1, 2 and

3, characterized in that the ring (35) has a long arm (54), on which are mounted, on both sides, contact plates (55) and a short arm (56), with which tapping plates (57) carried by arm (59) of the tapping contact element (44) make contact on both sides, and the contact plates (55) are in engagement at their outer end with an eccentric journal (58) of the fixed contact element ( 14).

6. Three-phase selector for an on-load tap changer according to claim 1, characterized in that as a variant, the wide segment is replaced with a normal narrow segment, on either side of which two insulating columns (60, 61) are located, mounted between the upper flange (11) and the lower flange (12), moreover the tapping contact elements (44, 45) are fixed in tiers on these columns with the arrangement according to claim 3.

APPLICATION:

7 figures

LITERATURE:

1. "On-load Tap-changer type UCG", ABB Components, Sweden;

2. BG33410, H01F 29/04;

3. 'Όη-load Tap-changer type RS5.3" Hyundai Heavy Industries Co., Bulgaria; 4. BG62748B1, HO IF 29/04

Description:
THREE-PHASE SELECTOR FOR ON LOAD TAP CHANGER WITH

INSULATED PHASES

TECHNICAL FIELD

The invention relates to a three-phase selector for an on-load tap changer with insulated phases. The on-load tap changers are embedded into the power transformers and regulate their high voltage under load, i.e. without interrupting the power supply to consumers. The selector works together with a power diverter switch with insulated phases and is used in delta connected transformer's windings.

BACKGROUND ART

It is known three-phase selector for an on-load tap changers with insulated phases (1), comprising an upper bearing flange and a lower bearing flange, between which a certain number of insulating columns are cage-like mounted. On each column are located in tiers by one even and one odd stationary contact element per phase. On the upper flange there is one even and one odd Geneva cross wheels, which are connected by an even and an odd driving insulating shaft and which are located at the centre of the selector. Around the shafts are arranged in tiers by one even and one odd current-carrying ring per phase. Each ring has T-shaped holder, attached to a separate insulating column. From these holders is made the connection with the power diverter switch through external conductors. Three horizontally positioned holders are attached to the even driving insulating shaft with current-carrying plates, mounted on them. Also, three horizontally positioned holders are attached to the odd driving shaft with current-carrying plates, mounted on them.

The disadvantage of this selector for an on-load tap changer is that, it has a great height due to the fact that the current-carrying rings and their attachment are positioned at two different levels. Another disadvantage is that, the fixing of the rings by one Γ -shaped carrier is unstable and can lead to a deviation from the horizontal position and deterioration of contact. The disadvantage is that additional insulating columns are required, which complicates the construction. The external conductors increase the cross gauge of the selector, which does not allow to realize a compact construction. The wires must be installed after the on-load tap changer is embedded in the transformer.

Another selector for an on-load tap changer with insulated phases is known (2), in which each insulating column is composed by two parallel insulating bars, connected to insulating plates. Three even stationary contact elements for the three phases are attached on one side of the column, and three odd stationary contact elements for the three phases are attached on the other side of the column. T-shaped carriers of the current-carrying rings are attached to the insulation plates. Besides a current-carrying T-shaped bearer, additional reinforcing T-shaped elements are used.

The disadvantage of this selector is that, the height is also large and the additional reinforcement complicates the construction. The disadvantage is also that, the conductors connected from the selector to the power diverter switch increase the cross gauge and make the installation difficult.

A selector with isolated phases (3) is known also, which is for a higher rated current (e.g.1250 A). The construction is more stable and has more number of insulating columns, separately for even and for odd fixed contact elements. The current-carrying rings are carried by T-shaped current-tapping elements and have additional reinforcement. These elements are attached to cages from insulating columns.

The large height and the complicated construction are also disadvantages by this selector. Another disadvantage is that, the external wires increase the cross gauge and make the installation difficult.

The height is reduced in another known selector with isolated phases (4). It contains an upper flange with an even and odd Geneva cross wheel, a lower flange and a cage, made of segments, cut-out of an insulating cylinder, mounted between the flanges. Even and odd stationary contact elements are located in tiers on the segments per the three phases. In the centre of the selector there are an even driving isolating segment, connected to the even Geneva cross wheel and an odd driving isolating segment, connected to the odd Geneva cross wheel. On the even driving segment are mounted three even current-carrying rings with arms, one-sided o.f which are attached contact plates with contact springs. In an analogous way, the odd driving segment has three odd current-carrying rings with arms and contact plates. There are current- tapping contact elements, radially at the level of the current-carrying rings,, attached to additional insulating elements, mounted on the periphery of the cage.

The disadvantage of this selector with insulated phase is that, the radial current- tapping contact elements are cantilever mounted and the contact of their current- carrying plates with the rings is possible to be not exactly. The current-tapping is worsened and a possibility for overheating appears. Another disadvantage here is that, the wires connecting the selector with the power switch are located on the periphery of the cage, increase the cross gauge and makes the installation difficult.

DISCLOSURE OF INVENTION

The task of the invention is to provide a three-phase selector for an on-load tap changer with insulated phases with simplified and compact construction. The attachment of the contact systems must be stable and guaranteed during operation. The conductors that connect the selector with the power diverter switch must be located next to the preselector, so that the on-load tap changer can be , mounted in the transformer as a complete mounting unit, i.e. without the need for additional mounting of the wires.

The task is solved with three-phase selector for on-load tap changer with insulated phases, containing an upper flange with a double transfer element and two Geneva cross wheels and a lower flange. Several segments made of insulating material are mounted between the two flanges with even and odd fixed contact elements fixed thereon. In the centre of the selector there are even and odd driving insulating segments with concentrically located thereon, even and odd current-carrying rings with arms. In a similar way there is an odd driving isolation segment with three current-carrying odd rings with arms. The even and odd arms are mounted on one side to the current-carrying plates, connecting the electrically rings to the fixed contact elements. Radially on the rings there are tapping contact elements with arms carrying tapping contact plates making contact with the rings. According to the invention, the selector has a wider insulating segment, on which, in addition to even and odd fixed contact elements, even and odd tapping contact elements are mounted in two rows for the three phases. These elements have arms with tapping contact plates rubbing on the rings. The rings have an edge with a stem located at the end of the arm. Thus guarantees accurate interaction of the contact stems and the rings.

The wider insulating segment is located beside a preselector, moreover the fixed even contact elements numbered last are mounted in tiers in the middle thereof. On one side of the fixed contact elements n segment, the tapping contact elements AI, BII and BI are fixed in tiers, and on the other side - the tapping contact elements All. Cll and CI. These tapping contact elements are connected with two bundles of conductors to the fixed contact elements of the power diverier switch.

As a variant, the stem located at the end of the arm of the tapping contact element is replaced with a roller. The other variant is when the ring has a long arm, on which are mounted on both sides contact plates and a short arm, with which tapping plates carried by arm of the tapping contact element make contact on both sides. The contact plates are in engagement at their outer end with an eccentric journal of the fixed contact element.

As a variant, the wide segment is replaced with a normal narrow segment, on either side of which two insulating columns are located, mounted between the upper flange and the lower flange. The tapping contact elements are fixed in tiers on these columns.

An advantage of three-phase selector for an on-Ioad tap changer with insulated phases, according to the invention is that, it has a simplified and small-size construction and can be incorporated into the transformer without disassembling and assembling the external wires. Another advantage is that, the tapping contact elements are relative to the rings, which ensures accurate and reliable contact. An advantage is that, there is a variant of a contact system for larger nominal currents. BRIEF DESCRIPTION OF THE DRAWINGS

An example embodiment of three-phase selector of an on-load tap changer with isolated phases according the invention is shown on the attached figures, of which:

Figure 1 is a longitudinal section E-E through the three-phase selector, where are visible the main even and odd contact systems.

Figure 2 is a cross-sectional H-H through the selector with shown main and current-tapping contact systems.

Figure 3 is a longitudinal section F - F through the selector with shown current- tapping contact systems.

Figure 4 is a scheme of the connections between the selector and the power diverter switch D.

Figure 5 is a section through a main and a current-tapping contact node in three variants (a, b, c).

Figure 6 is a longitudinal section G-G through the selector in a variant of take- out contact systems, attached on two vertical insulating columns.

Figure 7 is a cross-sectional of the selector of Figure 6.

EMBODIMENTS OF THE INVENTION

The immobile contact elements are numbered from 1 to 10 (Fig 1, Fig 2) where L 3, 5, 7 and 9 are odd and 2, 4, 6, 8 and 10 are even. The deviations from the regulating coil of the power transformer are connected to them in a known way.

The carrier structure of the three-phase selector is composed by an upper flange 1 1, a lower flange 12 and three segments cut-out of an insulating cylinder, two segments 13 of which are with two even 14 and odd 15 stationary contact elements per phase. The third insulating segment 16 has by six contact elements per phase. The three phases A, B, C are located in tiers one under the other. The driving mechanisms are mounted on the upper flange 11. It is composed of an even Geneva cross wheel 17, an odd Geneva cross wheel 18 and a double transfer element 19 with two driving rollers 20 and 21, located on both sides of the transfer element 19 at 180° from each other. The double transfer element 19 is mounted on a vertical axis 22, which is mounted on the upper flange 11. The even Geneva cross wheel 17 is attached to a shaft 23 with an arm 24 to which is fixed the upper end of a vertical, odd driving segment 25, cut-out from an insulating tube. At its lower end the segment 25 is connected to an arm 26, mounted on an axis 27, mounted in the middle of the lower flange 12. The odd Geneva cross wheel 18 is attached to a bush 28 mounted on the upper flange 11. The upper end of an odd driving segment 30 is connected to a shoulder 29 of the bush 28, which is also mounted down to axis 27 by arm 31. To the odd Geneva cross wheel 18 is fixed a known disc 32, which interacts with a two-arm lever 33 mounted on a axis 22, which in a known way acts a known not shown preselector.

Even current-carrying discs 35 are mounted on the even driving segment 25 with arms 36 by metal clamps 34. Current-carrying contact plates 39 are mounted onesided on the arms 36 by studs 37 and contact springs 38. In a similar way, three odd current-carrying discs 40 are mounted to the odd driving segment 30 with arms 41, to which are one-sided attached odd contact plates 42. The current-carrying discs 35 and 40 have a board 43, whose meaning will be explained later.

The current- tapping from disks 35 and 40 to the power diverter switch is visible in Fig. 2 and Fig. 3. Even 44 and odd 45 tapping elements are mounted on the insulating segment 16. They, respectively, have arms 46 and 47 on which are fixed even 48 and odd 49 current-tapping plates with studs and contact springs. The tapping elements 44 and 45 should be extended to a larger radius from insulating considerations, which is provided by insulating sleeves 50.

The electrical scheme of the tapping elements connection of the three phases of the power diverter switch D is shown on a Fig. 4. This is done by externally mounted conductors.

On a fig. 5 are shown three variants of a combination of the current-carrying even plates 39 and the current-tapping plates 48 during their mismatch. On a pos. "a" the arm 46 of the tapping element 44 has a stem 51, which touches the board 43 of the disc 35 and fixes the arms 46 so that it cannot be displaced upwards. This would degrade the correct contact. On a pos. "b" the stem has been replaced with roller 52, in order to avoid the eventually increased friction between the board 43 and the stem 51. The contact elements 14 and 44 are fixed to the insulating segment 16 by special nuts 53, formed with a spherical face.

For the purpose of conveying a higher current is provided a variant on pos. "c".

In this case the shoulder of the disc 35 has two parallel feathers. One, 54 is longer and two pairs tapping plates 55 contact on him by both sides. The other feather 56 is shorter and two pairs tapping plates 57 contact on him by both sides. The contact body 58 of a contact element 14 and the arm 59 of the contact tapping element 44 have a special shape.

In Fig. 6 and Fig. 7 the contact tapping elements 44 and 45 have a different design and are mounted on two insulating columns 60 and 61. The action of the three- phase selector is similarly to other selectors of a similar type. The double translation 19 is rotated on 180° and rotates in shifts the discs 35 and 40 through the Geneva wheels 17 and 18 and the insulating segments 25 and 30. So the contact plates 39 and 42 are moved in shifts from one contact element 14, respectively 15 to the neighbouring one.