EP2756510A1

EP2756510A1 - On-load tap changer

Info

Publication number: EP2756510A1
Application number: EP12751294.5A
Authority: EP
Inventors: Silke Wrede
Original assignee: Maschinenfabrik Reinhausen GmbH; Maschinenfabrik Reinhausen Gebrueder Scheubeck GmbH and Co KG
Current assignee: Maschinenfabrik Reinhausen GmbH; Scheubeck GmbH and Co
Priority date: 2011-09-17
Filing date: 2012-08-09
Publication date: 2014-07-23
Also published as: IN2014CN00476A; CN103797555A; KR20140060296A; US20140159847A1; WO2013037573A1; DE102011113718A1; JP2014531754A; BR112014002337A2

Abstract

The invention relates to an on-load tap changer consisting of an energy store, a drive shaft designed as a screw spindle, vacuum switching tubes and a contact carrier and vertically arranged tap contacts. Actuation of the vacuum switching tubes occurs in dependence on the contacts. According to the invention, the vacuum switching tubes are actuated via cam discs and deflection assemblies. In parallel, the contacts attached to the contact carrier are moved vertically by the drive shaft and the tap contacts are thus actuated.

Description

OLTC

The invention relates to an on-load tap-changer. On-load tap-changers and Lasiwähier are used to transform the transformers

Winding taps of these transformers switch under load and thus

Balancing voltage changes at the consumer.

On-load tap-changers, as known from the published patent application DE10055406C1, usually consist of a selector for power-free preselection of those

Winding taps of the transformer to be switched to, as well as a diverter switch for the actual uninterrupted switching from the previously connected winding tap to the new, preselected winding tap. There are at least two contact paths in the voter, with corresponding ones

A contact path leads via a closed contact the current, while on the second contact path, the next winding tapping is preselected to carry the current after the load switching. The actual load switching takes place with the aid of vacuum interrupters or mechanical contacts. Due to the oil contamination arising during switching, the vacuum interrupters or the mechanical contacts with the associated mechanical components are accommodated in a separate oil cylinder. The selector is due to the type either in the transformer housing or in a separate oil cylinder.

A disadvantage of the on-load tap-changer is that they consist of many components. As a result, the assembly and maintenance are very time-consuming and thus expensive.

Load selectors, as known from the published patent application DE3833126A1, consist inter alia of an oil tank cylinder. This is made of an insulating material and has a radially arranged, three-part cam track inside. Below the cam track are three externally arranged power terminals, which are connected to a slip ring located inside. Above the cam track are the step contacts, which are connected to the respective taps of the stepped windings and engage in the interior of the cylinder. Through the interior of the oil cylinder cylinder extending from an insulating material switching shaft extends. At this, two, over a base plate and a partial cylinder horizontally mounted vacuum interrupters mounted in a contact carrier, sliding contacts with guide arms and numerous other parts. By the rotation of the

Switching shaft, the cam track is scanned with the individual roles of the switch contact carrier. As a result, the individual vacuum interrupters are actuated, resulting in a predefined switching sequence.

A disadvantage of such a load selector is that the size and location of the

Vacuum interrupters set minimum requirements for the installation space and thus at the circumference of the oil cylinder. Due to the radial arrangement of the connections for the individual winding taps on the circumference of the oil cylinder and the given

Minimum distances of neighboring terminals, is the division, i. the maximum number of connections at a certain extent, limited. In addition, you can build the load selector for reasons of economy and space requirements in a transformer not arbitrarily large.

Another disadvantage is the weight of the shift shaft, which by the amount of

Components is determined and must be moved when switching. Because the

Switching operations take place in fractions of a second, enormous forces must be applied to move the SchaltweHe with the entire contact assembly in motion. After completion of the shading process, however, these masses must also be braked again. This leads to a high stress on the individual components, a high

Wear and frequent service intervals.

In addition, as the load selector expands to include additional connections for additional winding taps of rewinds, the entire circuitry must be redesigned and designed. Otherwise, the function could not be guaranteed and the required shut-down times could not be met.

The object of the invention is to provide an on-load tap changer, which combines the advantages of an on-load tap changer and a load selector, while having a low plastic space and can be expanded in the simplest way to additional shadow contacts.

This task is performed by an on-load shaver with the characteristics of the first

Claim solved. The subclaims relate to advantageous developments of the invention. The invention is based on the general idea to fix fixed by cam actuated switching contacts (vacuum interrupters) and both the tap contacts, to switch from one winding tap to the next, and the contacts and Ableitkontakte, which are actuated by a screw vertically with each other, below the switch contacts, to arrange.

The invention will be explained in more detail by way of example with reference to drawings.

Show it:

Fig. 1 an on-load tap changer according to the invention

Fig. 2 shows a possible switching sequence of an on-load tap changer according to the invention from a first tap contact to a second tap contact

Fig. 3 shows a possible switching sequence of an on-load tap changer according to the invention from a second tap contact to a first tap contact

Fig. 4 shows another embodiment of the contacts in Figure 1 is an inventive, three-phase on-load tap-changer 1 for

Stepped transformers shown. At the upper end of the on-load tap changer 1, a force accumulator 2 is arranged. This operates as trained as a screw spindle

Drive shaft 3, at the top of at least two cams 4 are fixedly arranged. The description always deals with only one phase, but the embodiment according to the invention applies to each of the three phases. By rotation of the drive shaft 3 and attached to her cams 4 can with the help of

Umlenkanordnungen five vacuum cells 6 and 7 are opened or closed.

In addition, a contact carrier 8 is mechanically connected to the drive shaft 3. Depending on the direction of rotation, the contact carrier 8 can move vertically upwards or downwards without rotating itself. The contact carrier 8 consists of a sleeve member 9 and at least one contact arm 10. The sleeve member 9 is inside The sleeve member 9 serves as a connecting means between the drive shaft formed as a screw 3 and the contact carrier 8. At one end of the contact arm 10 at least two galvanically separated contacts 11 and 12 are arranged. In the example shown, the contacts 1 1 and 12 are designed as sliding contact finger pairs.

Parallel to the drive shaft 3 each contact arm 10 at least two corresponding Ableitkontakte 13 and 14 are assigned vertically. The Ableitkontakt 13 always has an electrically conductive and mechanically sliding connection to one end of the contact 11. Since it is in Beispie! is a contact finger pair, the diverter 13 slides in between. This also applies to the discharge contact 14 and the contact 12th

In addition, the contact arm 10 via a recess 15, in the form of a bore with one of the Ableitkontakte, here Ableitkontakt 13, mechanically connected. As a result, the discharge contact 13 also has the function of a guide for the contact carrier 8 and prevents it from rotating with the drive shaft 3.

Also parallel to the drive shaft 3, each contact arm 10 is assigned an insulating rod 16 made of an electrically non-conductive material. In Isollerstab 16 corresponding to the contacts 11 and 12 electrically conductive step contacts 17 are arranged linearly along a vertically extending path. These are mutually offset and extend from the inside of Isoiferstabes 16 to the outsides. On the outside of the insulating rod 16, the different are at the stage contacts 17

Winding taps of the control transformer connected, in conjunction with other insulating bars 16, a framework for the on-load tap-changer 1 can be formed. It is also conceivable, however, a simple cylinder of an electrically non-conductive material, instead of isolierstäbe 16 for fixing the tap contacts 17. Since the contacts 1 1 and 12 are designed as sliding contact finger pairs, slide the tap contacts 17 between them. Thus, at one end of the contacts 11 and 12 are the tap contacts 17 and at the other end the Ableitkontakte 13 and 14. By this arrangement, a conductive connection between the tap contacts 17 and the Ableitkontakten 13 and 14 are made. In order to allow a flow of the load current, the vacuum interrupter 7 and the Ableitkontakt 14 are electrically connected to each other. Vacuum interrupter 6 is electrically connected by an additional resistor 18 to the power terminal. The connection can be realized for example by copper strands or wires. Resistor 18 shown in FIG. 1 is so-called resistance package.

In Fig. 2, the switching sequence of the on-load tap-changer 1 according to the invention by the individual circuit diagrams A - H is shown. The initial state is shown in circuit diagram A. Here are both contacts 11 and 12 at the same stage contact 17. Both vacuum interrupters 6 and 7 are closed, due to the series-connected

Resistor 18, the current flows through the Ableitkontakt 14 through the vacuum interrupter 7 to the derivative 19th

By triggering the energy storage 2, the stored energy is released by rotation of the drive shaft 3. Through the sleeve member 9 of the contact carrier is moved linearly down or up to the next stage contact 17. First, the contact 1 1 of the tap contact 17 (circuit diagram B) dissolves. In the next step, the vacuum sight tube 6 is opened via a deflection arrangement 5 with the aid of a cam disc 4, which is likewise driven by the drive shaft 3 (diagram C). Until then, the contact carrier 8 has covered such a way that contact 11 is applied to a next stage contact 17 (diagram D), up to this point, the current through contact 12 and

Vakuumschaitube 7 flowed to the discharge 18. By one of the cams 4 now the vacuum sight tube 8 is closed. This creates the so-called, circular current (diagram E). Another cam 4 then opens the vacuum sheath tube 7 (diagram F), so that the windings of the adjacent stage contact 17 can be tapped. In the next step, the contact carrier 8 has moved so far that the contact 12 rests against the step contact 17. In the last step (diagram H), the contacts 1 1 and 12 have reached their end position and one of the cams 4 closes the vacuum sheath tube 7, so that the current can flow through this to the derivative 19.

In Fig. 3 the Schaitablauf shown in Fig. 2 is shown in reverse order by the circuit diagrams I - P. The initial position (circuit diagram l) corresponds here to the

End graduation (diagram H) in Fig. 2. Both vacuum sight tubes 6 and 7 are closed. The current flows from the tap contact 17 via the contact 14 and the vacuum sheath tube 7 to the derivative 19. After the triggering of the energy accumulator 2, the drive shaft 3 in the turned opposite direction, as described in Fig. 2. The contact carrier 8 moves in the direction of a next stage contact 17. Before the contact 14 releases from the tap contact 17, a cam disk 4 opens the vacuum interrupter 7 (circuit diagram J). The current now flows through the contact 11, the Derleitkonfakt 13, the vacuum interrupter 8 and the resistor 18. After the contact 14 has arrived at the adjacent stage contact 17 (Schafbiid K), the vacuum interrupter 7 is closed by a cam plate 4 (circuit diagram L). In this position, the so-called circular current is created. As a result of the further rotation of the drive shaft 3, one of the cam disks 4 actuates the vacuum interrupter 6 and opens it. Now the windings of the adjacent tap contact 17 are tapped (circuit diagram M). After the contact 11 has detached from the tap contact 17 (circuit diagram N), the vacuum interrupter 6 is closed (diagram O). In the

End position are the contacts 1 1 and 12 at the tap contact 17. The current flows back through the contact 12, the Derleitkonfakt 14 and the Vakuumschaitube 7 to

Derivative 19.

Compared to conventional load selectors, only the camshafts 4 and the contact carrier 8, with the associated contacts 11 and 12, are moved by the drive shaft 3. These few components are lighter overall, so less energy is needed to move them. The vacuum interrupters 6 and 7 and the resistor 18 are fixed. The loads generated during braking of the parts after a changeover also decrease. In addition, the so-called bouncing, when opening or closing the vacuum interrupters 6 and 7, is reduced by the fixed arrangement.

By separating the vacuum interrupters 6 and 7 of the contacts 11 and 12 of the on-load tap-changer 1 is more compact and requires less space. This is further facilitated by the vertically aligned vacuum interrupters 6 and 7, the

Reduce the diameter of the entire assembly. In general, the compact design has fewer components compared to on-load tap changers of the prior art.

This makes assembly, installation and maintenance less time-consuming and thus

cost-effective. Due to the vertical arrangement of the step contacts 17 is the

On-demand tap-changer 1 can be easily extended downwards if required and can easily be extended by additional contacts for further control windings. The extension to further developments is much easier to implement than with conventional ones

On-load tap-changers or load selectors. FIG. 4 shows an alternative form of the contacts 11 and 12. These are not designed as sliding contacts, but have at the ends conductive Rolfen 20, in the up and down movement can be reduced by the rolling wear of the contacts 11 and 12.

LIST OF REFERENCE NUMBERS

1 on-load tap-changer

2 energy storage

3 drive shaft

4 cams

5 deflection arrangement

6 vacuum interrupter

7 vacuum interrupter 3 contact carrier

9 sleeve element

10 contact arm

11 contact

12 contact

13 abteit contact

14 leakage contact

15 hole

16 insulating rod

17 step contact

18 resistance

19 derivation

20 roll

Claims

claims

1. On-load tap-changer (1) for tapped transformers for uninterrupted switching from one tap contact (17) to an adjacent further tap contact (17), with a force store (2), wherein a vertically arranged rotatable drive shaft (3) is provided, wherein the drive shaft (3 ) is mechanically in communication with a contact carrier (8), wherein the contact carrier (8) one or more contacts (11, 12) for selectively Beschälten fixed stage contacts (17) and Ableitkontakte (13, 14) are provided, which via vacuum tubes ( 7, 8) are electrically connected to a lead (19),

characterized,

in that the fixed step contacts (17) are arranged linearly along a vertically running track,

the drive shaft (3) is connected to the contact carrier (8) via a screw spindle in such a manner that, upon rotation of the drive shaft (3), the contact carrier (8) performs a vertical movement,

that the vacuum interrupters (7, 8} are firmly fixed in one area and

that the vacuum interrupters (7, 8) by cams (4), which coincide with the drive shaft

(3) are connected by deflection arrangements (5) are actuated.

2. load stage shaker (1) according to claim 1,

characterized,

the contact carrier (8) has a contact arm (10) with a recess (15) and is thus movably connected to at least one diverter contact (13) or (14) and serves as a guide for at least one of the diverter contacts (13) or (14).

3. on-load tap-changer (1) according to one of claims 1 or 2,

characterized,

in that the fixed step contacts (17) are attached to insulating bars (16) and the insulating bars (16) can be connected to form a framework.

4. on-load tap-changer (1) according to one of claims 1 to 3,

characterized"

the step contacts (17) on an insulating cylinder or on segments of a

Insulating cylinder are attached.