WO2013017512A1

WO2013017512A1 - Linear drive for an on-load tap changer

Info

Publication number: WO2013017512A1
Application number: PCT/EP2012/064645
Authority: WO
Inventors: Dieter Dohnal
Original assignee: Maschinenfabrik Reinhausen Gmbh
Priority date: 2011-08-03
Filing date: 2012-07-26
Publication date: 2013-02-07
Also published as: DE102011109272B4; DE102011109272A1

Abstract

The invention relates to a linear drive for an on-load tap changer, in which a switching rod (1) is provided which has, alternately, ferromagnetic (m) and nonmagnetic (n) sections. A plurality of separately excitable coils (2‑5) are arranged concentrically around this switching rod (1). By defined actuation of one of the coils (2‑5), a movement of the switching rod through a switching step optionally in one of the two longitudinal directions is made possible.

Description

Linear drive for a step changer

The invention relates to a linear drive for a tap changer for interruption

Switchover between voltage taps of a tapped transformer.

Tap changers have been an established state of the art for many years. As a rule, they have an insulating material stand or an insulating cylinder on which fixed selector contacts, which are in each case electrically connected to a winding lead-out of the tap winding of the transformer to be controlled, are arranged in at least one, usually a plurality of horizontal planes. In the center of this circular arrangement of fixed selector contacts is then a rotatable drive shaft which carries movable contacts, by means of which the fixed selector contacts are actuated. It takes place in this widespread type of tap changers so a rotational movement, which is usually generated by a triggered energy storage. A typical example of such a tap changer shows the DE 38 33 126th

In addition to these Stufenschaltem but those with linear contact movement are known. DE 42 37 165 C1 describes a single-pole tap changer with linear contact actuation, wherein the switching mechanism of an elevator carriage and a through this by means of a

Force accumulator pull-up output part consists. The stripping section runs after the triggering of the energy storage abruptly after the elevator carriage. The disadvantage of this arrangement is mainly that an energy storage, here a spring energy storage, is necessary, which is elaborate and complex and must be mounted previously. After its release, it releases suddenly and abruptly a high energy, which is quite problematic. The high kinetic energy leads to a heavy load on the moving components and can also unwanted shocks or

Cause vibrations, especially when the tap changer reaches its end position.

From DE 44 02 087 A1 a damping device for such a linearly operated tap changer with a force storage device is already known. By means of this damping device, which operates hydraulically, part of the released energy of the energy accumulator is to be "collected." However, this known solution does not eliminate the cause, but attempts to reduce the symptom.

From DE 10 2009 017 197 A1, a further linear actuated tap changer, here with semiconductor switching elements, known. In this so-called hybrid switch (hybrid because both semiconductor switching elements and mechanical components are present) are provided on a web extending fixed contact rails, which together by means of a

Contact slide movable contact bridges are contactable. For such hybrid switches are so far - except the known spring force storage - no satisfactory drives available. However, the known power storage are relatively unsuitable for these tap changers with semiconductor switching elements; the disadvantages have already been listed above.

The object of the invention is to eliminate these disadvantages and to provide a suitable linear drive for a tap changer, which requires no separately retractable energy storage more.

This object is achieved by a linear drive with the features of the first claim. The subclaims relate to advantageous developments of the invention.

The invention is based on the general inventive idea, an electromagnetic

Direct drive to use. This not only eliminates the actual energy storage, but it is no longer necessary mechanical drive by a separate motor at all. According to the invention, a drive rod is provided which is in communication with the components to be moved of the tap changer, which in turn carry the movable contacts. The drive rod consists of alternating ferromagnetic and non-magnetic sections. Around the drive rod around spatially successively arranged coils are arranged concentrically in its direction of movement, which can be pulsed electrically in any order for a short time, ie current is flowing through short-term. As a result, a fast, gradual movement of the drive rod is realized.

It is particularly advantageous to ensure a stable, defined position of the drive rod by a latching in the stationary state of the tap changer. This can be done advantageously by mechanical locking means, which particularly advantageous in addition to the leadership of

Drive rod can serve in their movement in the longitudinal direction.

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

Show it:

1 shows a linear drive according to the invention in a schematic representation

Figure 2 different positions, d. H. Operating sequences, such

linear drive

Figure 3 shows a corresponding sequence of the respective excited coils for generating a

exemplary step sequence of the linear drive

Figure 4 shows an advantageous circuit for energizing each one of the coils.

FIG. 1 schematically shows a linear drive according to the invention for a tap changer. It has a shift rod 1, which is designed to be longitudinally displaceable. Around this shift rod 1 around four electric coils 2, 3, 4, 5 are arranged concentrically in the longitudinal direction seen here.

Between each of the coils 2 ... 5 and the Schaitstange 1 remains an air gap. Each of the coils 2 ... 5 is electrically controlled separately: this will be explained later in more detail. The shift rod 1 is alternately divided into ferromagnetic portions m and non-magnetic portions n. The individual sections have, seen in the direction of movement, each identical length a. This length a corresponds particularly advantageous also the height of the individual, identically constructed coils 2 ... 5. The distance b between the coils 2 ... 5, again seen in the direction of movement of the shift rod 1, is half of the value a for the length of the different sections m, n. At a distance b are provided on the shift rod 1 detents 6, of which for reasons of clarity, only a single is provided with reference numerals. Above and below the region of the coils 2 ... 5 are upper locking elements 7 and lower locking elements 8, each of which - against the force of springs 9 with - position-dependent - different notches 6 correspond and thus can fix the shift rod 1. By different control of individual coils, the shift rod 1 can each be actuated in the longitudinal direction by a certain distance, which corresponds exactly to the distance b between two coils 2 ... 5 and thus also the distance between two adjacent detents 6. Accordingly, the shift rod 1 is fixed in these stationary positions. C denotes the axis of symmetry in the longitudinal direction of the switching rod 1, c and d denote two exemplary horizontal planes for latching elements 7, 8.

Figure 2 shows the possible positions of the shift rod 1 with different control of individual coils. This will be explained in connection with the figure 3, in which the corresponding

Drive sequence is shown schematically. It can be seen that, starting from a position 1, by energizing the upper coil A (which corresponds to the coil 2 in Figure 1), the shift rod 1 is guided upward until the corresponding magnetic portion is completely inside the coil A. , This position 2 is reached. For further actuation in the same direction, the coil B (which corresponds to the coil 3 in FIG. 1) is in turn energized until, in turn, the corresponding magnetic region is completely within this coil B. To switch to the same direction then the coil 10 is energized (which corresponds to the coil 4 in Figure 1); the sequence is repeated accordingly, as well as the repeated indexing in the same direction by brief excitation of the coil D (corresponding to the coil 5 in Figure 1). Upon a desired actuation of the shift rod 1 in the opposite direction, the coils are each actuated in opposite order. It can be seen that a movement of the shift rod 1 in both directions in each case by a constant path b is always possible by different control of individual coils. The path b results from the fact that the movement of the shift rod 1 starting after the activation of the corresponding coil is completed when the respective magnetic region, which is only halfway into this coil at the beginning of the movement, has been completely moved into it. The respective operating positions can be made possible in a particularly advantageous manner by the fixation shown in FIG. 1, but not shown in FIG. 2, by the detents 6 and respective detent elements 7, 8.

The illustrated latching elements 7, 8 can be designed in many ways, it can be, for example, spring-loaded balls, which engage in corresponding notches 6, it can also be used other means known in the art for it.

It is particularly advantageous to use such locking means for additional guidance support of the shift rod 1 and provide corresponding notches, for example, in each horizontal plane d, e several times, for example, offset by 120 degrees on the shift rod 1.

Figure 4 shows an advantageous circuit for DC excitation of the respective coils 2 ... 5. It has a power electronic component with power electronic switching elements, eg. B. GTO or thyristor, and is advantageously fed from a buffered memory, such as a capacitor. It is also possible within the scope of the invention, the required energy through an accumulator, z. B. to produce a lithium-ion battery. Of course it is also possible to supply the required voltage externally.

Overall, the invention allows a simple way with only a few components direct and accurate operation of a linear drive for a tap changer. Both conventional

Motor drives with an electric motor as well as an energy storage device, which provides the required kinetic energy after its release, are superfluous. By appropriate dimensioning of the drive rod 1 and the coils 2 ... 5 and varying the number of coils, both the speed of movement of the shift rod 1 and the number of possible positions and the corresponding shift paths vary within wide limits and adapt to the specific conditions.

Claims

claims

1. Linear drive for a tap changer for uninterrupted switching between winding taps of a tapped transformer,

wherein along a track extending mechanical contacts are fixed,

wherein a längsbewegbarer contact carriage is provided which carries at least one arranged and movable with him contact

and wherein the mechanical contacts are positionally contactable by the at least one longitudinally movable contact,

characterized,

that the contact carriage is mechanically connected to a switching rod (1),

that the switching rod (1) in its direction of movement alternately ferromagnetic portions (m) and non-magnetic portions (s), all of an identical length (a) that in the switching direction, d. H. Movement direction of the shift rod (1), around the shift rod (1) around a plurality of electrical coils (2 ... 5) are arranged concentrically

and that the coils (2 ... 5) are excitable separately.

2. Linear drive according to claim 1,

characterized,

the distance (b) of the coils (2 ... 5) from one another corresponds to half the length (a) of the ferromagnetic and non-magnetic sections (m, n).

3. Linear drive according to claim 1 or 2,

characterized,

the height of the coils (2 ... 5) corresponds to the length (a) of the ferromagnetic and non-magnetic sections (m, n).

4. Linear drive according to one of claims 1 to 3,

characterized,

that all coils (2 ... 5) are identical.

5. Linear drive according to one of claims 1 to 4,

characterized,

in that the energy for DC excitation of the respective coil (2 ... 5) is provided from a buffered memory or an accumulator.