CN114026665A

CN114026665A - Multi-phase selector-pre-selector arrangement for on-load tap changer

Info

Publication number: CN114026665A
Application number: CN202080046924.9A
Authority: CN
Inventors: B·瓦西列夫; G·马涅夫; P·D·马里诺夫; T·P·科凯夫
Original assignee: Hitachi Energy Switzerland AG
Current assignee: Hitachi Energy Co ltd
Priority date: 2019-06-25
Filing date: 2020-06-25
Publication date: 2022-02-08
Also published as: WO2020260497A1; EP3991190A1; EP3758034A1; KR20220006651A

Abstract

A multi-phase selector-pre-selector arrangement (10) for an on-load tap changer comprising: an insulating tube (100) surrounding an insulating compartment (110); a pre-selector (200) disposed along an outer wall of the tube; a selector device (300) arranged within the insulating compartment and comprising a first selector arm (310) and a second selector arm (320), wherein the first selector arm (310) comprises for each phase (L1, L2, L3) an odd number of moving contact elements (315-1, 315-2, 315-3), and wherein the second selector arm (320) comprises for each phase (L1, L2, L3) an even number of contact elements (325-1, 325-2, 325-3); and a drive mechanism (400) for operating the selector device (300), the drive mechanism (400) comprising a mounting element (410) on which the first (310) and second (320) selector arms are jointly mounted such that they are jointly moved by the drive mechanism (400).

Description

Multi-phase selector-pre-selector arrangement for on-load tap changer

Technical Field

The present disclosure relates to a multi-phase selector-pre-selector arrangement for an on-load tap changer.

Background

An on-load tap changer is a part of an electrical transformer and is used to switch the tapping of the transformer to regulate the high voltage of the output when the electrical transformer is in full operation (i.e. under load conditions). In the case of an on-load tap changer, the output power or the power supply does not need to be interrupted, resulting in a substantially continuous supply of output power even in the case of output voltage having to be regulated. The tap changer comprises a set of fixed contacts, each of which is connectable to a plurality of taps of a regulating winding of the power transformer. By selecting the tap to be connected or disconnected as desired, the output voltage of the transformer can be regulated. Typical on-load tap changers have a configuration for simultaneously changing the tap-off of multiple phases (e.g., three phases in a star configuration of transformer windings).

Known configurations of on-load tap changers include a multi-phase selector-pre-selector arrangement in which an insulating tube surrounds an insulating compartment. The selector device of the selector-pre-selector arrangement is mounted inside the insulating tube. The pre-selector device of the selector-pre-selector means is mounted on the outer wall of the tube, i.e. the side of the tube.

There are known selector devices that include a vertical insulating rod or selector arm for selectively bridging a stationary contact ring mounted on a pipe to select a desired tap. For example, document BG112740A describes a selector device having two selector arms for selecting an even number of electrical fixed contacts or an odd number of electrical fixed contacts, respectively. The two selector arms are arranged separately from each other and operate independently of each other. Thus, in conventional systems, the synchronization of the respective movements of the selector arms is complicated, while this configuration takes up a lot of space. Accordingly, a selector-preselector device that is compact and/or provides simple synchronization for movement of the selector arm is desired.

Disclosure of Invention

According to an aspect, a multi-phase selector-pre-selector arrangement for an on-load tap changer is provided. The apparatus includes an insulated tube, a pre-selector, a selector device, and a drive mechanism. An insulation tube surrounds the insulation compartment. The preselector is disposed along the outer wall of the insulating tube. The selector device is disposed inside the insulating compartment and includes a first selector arm and a second selector arm. The first selector arm comprises an odd number of moving contact elements for each phase. The second selector arm comprises an even number of moving contact elements for each phase. The drive mechanism is configured to operate the selector device. The drive mechanism includes a mounting element on which the first and second selector arms are commonly mounted such that they are moved together by the drive mechanism.

Typically, the mounting element is configured such that it provides a direct mechanical link between a mounted first selector arm and the mounted second selector arm. The direct mechanical link is typically devoid of any gearing, pivot members, joint members, etc. In an embodiment, the mounting element is a one-piece member, preferably a one-piece metal member.

By a common movement through the middle of the mounting member, the first and second selector arms may be mounted close to each other, resulting in a compact configuration.

Typically, but not limited to, the device has a three-phase configuration. Thereby, the first selector arm comprises a first phase even contact element, a second phase even contact element and a third phase even contact element. Likewise, the second selector arm comprises a first phase odd contact element, a second phase odd contact element and a third phase odd contact element.

According to another aspect, an on-load tap changer is provided. The on-load tap changer comprises a multi-phase selector-pre-selector arrangement as described herein. According to yet another aspect, a power transformer is provided. The power transformer comprises an on-load tap changer. The on-load tap changer comprises a multi-phase selector-pre-selector arrangement as described herein.

Further embodiments and aspects are apparent from the detailed description and from the dependent claims.

In an embodiment, the first selector arm and the second selector arm are mounted side by side on the mounting element. Unlike the conventional configuration in which a plurality of selector arms are usually mounted at opposite positions substantially on the outer circumference, the present configuration in which two selector arms are arranged side by side makes it easy to have a particularly small-sized and relatively rigid mounting element, which further improves compactness and synchronism.

In a further embodiment, the drive mechanism additionally comprises a spring energy accumulator for providing the rotational action.

In a further embodiment, the first selector arm and the second selector arm are arranged such that they each extend along an outer surface of the selector device from the top side to the bottom side.

In further embodiments, the drive mechanism comprises a geneva drive. The geneva drive is configured to advance the selector positions of the first and second selector arms in a step-wise manner. For example, but not by way of limitation, the geneva drive advances the selector position by rotating, for example, in eight or more positions, typically ten or twelve positions. According to this embodiment, in a particular configuration, the geneva drive includes a geneva gear and an input shaft. The input shaft is configured to drive the geneva gear such that the selector positions of the first and second selector arms are advanced.

In a further embodiment, one of the first and second selector arms each comprises a common moving contact element or a common terminal. In the above-mentioned exemplary non-limiting three-phase configuration, a respective one of the first and second selector arms comprises a first phase common moving contact element, a second phase common moving contact element and a third phase common moving contact element. Each of the even moving contact elements, the odd moving contact elements and the common moving contact element may have a contact bridge configuration. Each contact bridge may be configured such that it establishes a connection between fixed terminals (e.g., a fixed terminal ring disposed on the shunt switch, and a fixed output contact of the selector secured on the inside of the insulating compartment).

In an embodiment, the apparatus further comprises a shunt switch having a stationary terminal. Each contact element is configured to establish electrical contact with a corresponding one of the stationary terminals in accordance with the selector positions of the first and second selector arms.

In an embodiment, the multi-phase selector-pre-selector arrangement (or simply arrangement) may have one or more of the following advantages: the device adopts a simple and compact design which allows for simultaneous actuation of the even and odd arms of the selector. The drive of the two arms of the selector is driven by the same geneva gear. It is possible to easily install and remove equipment in the oil compartment of an on-load tap changer (abbreviated OLTC).

Drawings

Embodiments of the present disclosure will be described below with reference to the accompanying drawings, in which:

fig. 1 is a schematic perspective view of a selector apparatus of a selector-pre-selector device according to an embodiment;

FIG. 2 is a schematic perspective view of the selector apparatus of FIG. 1 as viewed from a different perspective;

fig. 3 is a schematic perspective view of a selector-pre-selector device according to an embodiment;

FIG. 4 is a schematic partial perspective view of the selector-pre-selector assembly of FIG. 3;

FIG. 5 is a schematic perspective view of a pre-selector;

FIG. 6 is a cross-sectional top view of a drive mechanism for a selector-pre-selector device, according to an embodiment; and

fig. 7 is a cross-sectional top view through a selector-pre-selector device, under an embodiment.

Detailed Description

Fig. 1 illustrates, in perspective view, a selector apparatus 300 of selector-pre-selector device 10 in accordance with an embodiment of the present disclosure. Fig. 2 shows the selector device 300 from a different perspective. For ease of explanation, the following explanation generally refers to fig. 1 and 2.

The column-type selector apparatus 300 of the embodiment shown in fig. 1 and 2 has a three-phase configuration, i.e., is constructed and arranged to perform synchronous tap selection of the first phase L1, the second phase L2, and the third phase L3. In the configuration shown, the diverter switches 500 attributed to the device are arranged radially within the columns of selector apparatus 300. The shunt switch 500 has a selector 300, i.e., a fixed terminal that selects its contact.

The first and

second selector arms

310, 320 are arranged side-by-side and each extend from a top side of the selector apparatus 300 to a bottom side of the selector apparatus 300. The first and

second selector arms

310, 320 are made of an insulating material, i.e., the first and

second selector arms

310, 320 are each configured as an insulating rod.

Odd number of moving contact elements 315-1 of the first phase (L1), odd number of moving contact elements 315-2 of the second phase (L2) and odd number of moving contact elements of the third phase (L3) are arranged on the first selector arm 310. Likewise, a first phase (L1) even-numbered moving contact element 325-1, a second phase (L2) even-numbered moving contact element 325-2 and a third phase (L3) even-numbered moving contact element 325-3 are arranged on the second selector arm 320. Moving contact elements 315-1, 315-2, 315-3; 325-1, 325-2, 325-3 have a contact bridge configuration. During assembly of the selector apparatus 300, the two insulating rods 310, 320 (first selector arm 310, second selector arm 320) are rotated by a defined angle to ensure that the moving contact elements 315-1, 315-2, 315-3; 325-1, 325-2, 325-3 are in place over the fixed contact counterparts of the moving contact elements.

In the embodiment shown in fig. 1 and 2, in addition to the odd-numbered moving contact elements 315-1, 315-2, 315-3 arranged on the first selector arm 310 and the even-numbered moving contact elements 325-1, 325-2, 325-3 arranged on the second selector arm 320, a first phase (L1) common moving contact element 316-1, a second phase (L2) common moving contact element 316-2 and a third phase (L3) common moving contact element 316-3 are arranged on the first selector arm 310. In certain embodiments not depicted in the drawings, a first phase (L1) common moving contact element, a second phase (L2) common moving contact element and a third phase (L3) common moving contact element may also be provided on the second selector arm 320.

The first and

second selector arms

310, 320 are mounted on a mounting element 410 coupled to the drive mechanism 400. The mounting element 410 is attached directly to the geneva gear 450. The mounting element 410 is made of steel. The mounting element 410 is attached to the first selector arm 310 and the second selector arm 320 by two metal joints. The mounting states of the first and

second selector arms

310, 320 are a common mounting state, i.e. the selector positions of the first and

second selector arms

310, 320 are commonly controlled, and the mounting element 410 is free from any joints, gears, etc. between the first and

second selector arms

310, 320. During tap selection, the first and

second selector arms

310, 320 thus rotate about the central axis. The mounting element 410 may also be referred to as a selector frame, wherein the selector frame carries two insulated rods (odd, even), namely a first selector arm 310 and a second selector arm 320. The

selector arms

310, 320 are in the shape of elongated insulating cylinders arranged parallel to each other. The

selector arms

310, 320 have three opposing apertures each for mounting the moving contact elements 315-1, 315-2, 315-3; 325-1, 325-2 and 325-3.

The drive mechanism 400 generally includes a spring energy accumulator for providing rotational motion. For example, as is evident from the cross-sectional view of fig. 6, in an embodiment, the drive mechanism 400 includes a geneva gear 450 and an input shaft 460. The selector frame is driven by geneva gear 450. Geneva gear 450 is in turn driven via input shaft 460. The geneva gear 450 and the input shaft 460 form a geneva drive that advances the selector positions of the first and

second selector arms

310, 320 in a step-wise manner.

In the perspective view of fig. 3, selector-pre-selector device 10 is shown according to an embodiment. A detailed partial view of selector-pre-selector assembly 10 is shown in fig. 4. Selector-pre-selector device 10 includes an insulating tube 100 surrounding an insulating compartment 110. The insulating tube 100 is made of an insulating material such as glass fiber. Insulating tube 100 provides the mechanical structure and robustness of selector-preselector assembly 10. The insulating tube 100 is fastened to the driving mechanism 400 by bolts. Typically, the insulation compartment 110 contains a filling of insulating oil. Inside the insulating compartment 110, a selector device 300 is arranged. The insulation compartment 110 separates the insulation oil of the active part of the transformer from the insulation oil of the selector device 300. The insulating compartment 110 is oil-tight. On the outer circumferential side of the insulating tube 100, a pre-selector 200 in the form of an insulating rod is provided so as to extend along the outer wall of the tube. Pre-selector 200 is attached to the housing of drive mechanism 400. Pre-selector 200 is configured to provide a rotational action driven by drive mechanism 400. Pre-selector 200 is shown in isolation in the perspective view of fig. 5. The pre-selector 200 includes a first phase (L1) pre-selector contact 210-1, a second phase (L2) pre-selector contact 210-2, and a third phase (L3) pre-selector contact 210-3.

As is apparent from the cross-sectional top view of fig. 7, the first selector arm 310 and the second selector arm 320 are mounted side-by-side. The pre-selector 200 extends substantially parallel to the direction of extension of the first and

second selector arms

310, 320.

It is to be noted that, although the above description relates to specific embodiments, those skilled in the art will recognize that the features described therein may be combined as appropriate and/or one or more features thereof may be changed or omitted as appropriate without departing from the spirit of the present application, the scope of which is defined by the claims.

Claims

1. A multi-phase selector-pre-selector arrangement (10) for an on-load tap changer, comprising:

an insulating tube (100), the insulating tube (100) surrounding an insulating compartment (110);

a pre-selector (200), the pre-selector (200) disposed along an outer wall of the tube;

a selector device (300), the selector device (300) being arranged within the insulating compartment and comprising a first selector arm (310) and a second selector arm (320), wherein the first selector arm (310) comprises for each phase (L1, L2, L3) an odd number of moving contact elements (315-1, 315-2, 315-3), and wherein the second selector arm (320) comprises for each phase (L1, L2, L3) an even number of moving contact elements (325-1, 325-2, 325-3); and

a drive mechanism (400), the drive mechanism (400) for operating the selector device (300), the drive mechanism (400) comprising: a mounting element (410), the first selector arm (310) and the second selector arm (320) being commonly mounted on the mounting element (410) such that the first selector arm (310) and the second selector arm (320) are commonly moved by the drive mechanism (400); and a spring energy accumulator for providing a rotational action.

2. The multi-phase selector-pre-selector device (10) according to claim 1, wherein said first selector arm (310) and said second selector arm (320) are mounted side-by-side on said mounting element (410).

3. The multi-phase selector-pre-selector device (10) according to any one of the preceding claims, wherein said first selector arm (310) and said second selector arm (320) are arranged so as to extend along an outer surface of said selector apparatus (300) from a top side to a bottom side.

4. The multi-phase selector-preselector apparatus (10) as claimed in any preceding claim, wherein said drive mechanism (400) comprises a geneva driver (450, 460), said geneva driver (450, 460) being configured to advance selector positions of said first selector arm (310) and said second selector arm (320) in a stepwise manner.

5. The multi-phase selector-preselector apparatus (10) as claimed in claim 4, wherein said geneva drive comprises a geneva gear (450) and an input shaft (460), said input shaft (460) configured to drive said geneva gear (450) to advance said selector positions of said first selector arm (310) and said second selector arm (320).

6. The multi-phase selector-pre-selector device (10) according to any one of the preceding claims, wherein one of the first selector arm (310) and the second selector arm (320) comprises a common contact element (316-1, 316-2, 316-3).

7. The multi-phase selector-preselector device (10) as claimed in claim 5, wherein a respective one of said first and second selector arms (310, 320) comprises a common moving contact element (316-1, 316-2, 316-3) for each phase (L1, L2, L3).

8. The multi-phase selector-pre-selector device (10) according to any one of the preceding claims, further comprising a diverter switch (500) having stationary terminals, wherein each contact element (315-1, 315-2, 315-3; 325-1, 325-2, 325-3; 316-1, 316-2, 316-3) is configured to establish an electrical contact with a corresponding one of the stationary terminals depending on the selector positions of said first selector arm (310) and said second selector arm (320).

9. The multi-phase selector-pre-selector device (10) according to any one of the preceding claims, wherein said mounting element (410) is designed as a one-piece component.

10. An on-load tap changer comprising a multi-phase selector-pre-selector device (10) according to any of the preceding claims.

11. A power transformer comprising an on-load tap changer comprising a multi-phase selector-pre-selector device (10) according to any of claims 1-9.