HK1168194B - Arrangement comprising a stepping switch and a control transformer - Google Patents

Description

The invention relates to an arrangement with a step switch and a control transformer, in particular an electronic step switch, in particular on a distribution transformer.

Step switches are used to switch between the winding contacts of a control transformer without interruption. They have been state of the art for many years and are known in numerous forms with mechanical contacts or vacuum switches or semiconductor switches as switching elements for load switching.

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From DE 912 366 C, an arrangement with a step switch and a control transformer is known as per the general concept of claim 1.

The disadvantage of the known arrangements with a step switch and a control transformer, where the step switch is located in the transformer or on the side of the transformer, is that a correspondingly wider or longer transformer design is required. Especially for distribution or local network transformers, such a correspondingly wider or longer transformer design, which includes the space for the step switch, would lead to correspondingly larger compact stations.

The purpose of the invention is therefore to provide for an arrangement with a step switch and a control transformer which does not increase the base area specified by the transformer and which allows an efficient, space-saving and cost-effective integration of the step switch with a control transformer.

This task is solved by an arrangement with the characteristics of the first patent claim.

The general idea behind the invention is to place the step switch above the iron yoke of the control transformer and thus above or in the control transformer as a whole. This is particularly advantageous for compact stations, which usually have enough space upwards. Especially for such compact stations, a minimum installation space is desired to keep the necessary ground acquisition for the installation as low as possible.

In a first embodiment of the invention, the mechanical contact system of the step switch is located below the transformer cap and thus inside the transformer, while the actual load switch is located above the transformer cap and thus outside the transformer.

According to another embodiment of the invention, the complete step switch, i.e. both the mechanical contact system and the load switch, is located below the transformer cover and thus inside the transformer.

It is particularly advantageous to separate the mechanical contact system and the load switch by means of an insulating execution plate.

It is further advantageous to envisage the load switch as a power electronic load switch with electronic switching devices such as thyristors or IGBTs.

In an embodiment with such a power electronic load switch and a separation from the mechanical contact system by the insulating execution plate mentioned above, the electronic components can thus be operated in air, while the mechanical contact system can be operated in oil - their preferred environment.

A separate cover is provided in a particularly advantageous way so that the power electronic load switch can be easily accessed separately from above.

The invention is explained in more detail below by means of examples of embodiments.

It shows: Figure 1 a first embodiment of an arrangement according to the inventionFigure 2 a second embodiment of an arrangement according to the invention.

The diagram in Figure 1 shows a boiler 1 of a control transformer, inside which are coils 2 and at least one iron yoke 3. Above the boiler 1 is closed by a transformer cap 4. Usually the complete boiler 1 is filled with oil. Above the transformer cap 4 are the MS line 5 and the NS line 6. The connection to the primary or secondary side of the winding 2 inside the transformer and the electrical connections from the top of the rule to the step winding switch are not shown separately. Above the iron yoke 3 is a step load switch, which contains an electronic transformer output plate 7 and a mechanical contact switch 8 located between the transformer caps. The load switch 7 and 8 are located on the top of the transformer. The two contacts are separated by a horizontal barrier, which is not visible when the transformer is running.

Figure 2 shows another embodiment of the invention in which, unlike the solution described above, both electronic load switch 7 and mechanical contact system 8 are located below the transformer cap 4 and thus in the boiler 1.

In both embodiments, the arrangement of the step switch above the iron yoke 3 ensures that the required base area for the arrangement is determined solely by the dimensioning of the winding 2 and the resulting size of the boiler 1.

As already explained, this advantage of reduced footprint is particularly important for distribution transformers in corresponding compact stations.

Claims (1)

1. Arrangement of a tap changer at a regulating transformer, wherein the tap changer comprises a mechanical contact system (8) for selection of a tap of a regulating winding of the regulating transformer as well as a load changeover switch (7) for the actual on-load switching over, wherein the regulating transformer comprises an oil-filled vessel (1) in which at least one yoke (3) and windings 2) are disposed, wherein the vessel (1) is closed at the top by a transformer cover (4) and wherein the mechanical contact system (8) of the tap changer is arranged within the vessel (1) below the transformer cover (4) and above the yoke (3), characterised in that the load changeover switch (7) is arranged outside the vessel (1) above the transformer cover (4) in air, that the load changeover switch (7) and mechanical contact system (8) of the tap changer are separated from one another by a horizontal insulating lead-through plate (9), that the load changeover switch (7) comprises electronic power switching means, particularly thyristors or IGBTs, for uninterrupted on-load switching over and that the regulating transformer is a local mains transformer or a consumer-proximal distributing transformer.