JPH0726825Y2 - Adjusting transformer load tap selector - Google Patents

Abstract

1. Load selector for step transformers with main (16) and step windings (18) for switching over from one tap to the next with fixed step contacts (1 to 14), which are arranged in a circle in an insulating cylinder (17) and are connected with the taps, and with switching contacts (20, 21, 22) of three current branches, which can be rotated simultaneously in the circle and are constituted by rollers, on a common contact carrier (15), - in which all three switching contacts (20, 21, 22), in each case, in their rest position conduct the potential of the same step contact (1 to 14) and lie in the direction of the switching movement in a series one after the other and - in which radial movements of the switching contacts (20, 21, 22) in respect of the contact carrier (15) are controlled by the fixed step contacts (1 to 14) which simultaneously constitute cams, characterised - in that the centre distance and accordingly for the contact carrier (15) the angle of rotation between a fixed step contact (1) connected to the main winding (16) and the two fixed step contacts (2 or 14) adjacent to said contact (1) is 20% to 60% greater than the centre distance or the angle of rotation between the other fixed step contacts (2 to 14) and - in that the sides of the step contact (1) connected to the main winding (16) and the sides facing said contact (1) of the two adjacent step contacts (2 to 14) bear extensions which are similar to a horn in cross section and are held at a distance from the surface of the insulating cylinder (17), the distances of which extensions from each other are approximately equal to the distances of the other step contacts (2 to 14) in the direction of the switching movement.

Description

[Detailed description of the device]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an on-load tap selector for switching a regulation transformer having a main winding and a tap winding from one tap to the next tap.

[0002]

2. Description of the Related Art In order to switch an adjusting transformer having a main winding and a tap winding from one tap to an adjacent tap,
A fixed tap contact, which is arranged on one circumference in an insulating cylinder and is connected to a tap, and a three-current branch roller switching contact supported by a common contact support and capable of rotating simultaneously on the circumference. And all three switching contacts guide the potential of the same tap contact in their rest position, and they are arranged in series in the direction of the switching movement, so that the radial movement of the switching contact with respect to the contact carrier is A switching contact device for a tap selector under load, such as being controlled by a fixed tap contact which at the same time acts as a cam, is for example disclosed in DE-A-3326549 and DE-A-3401297. Are known from the specification.

Further, the German Patent Application Publication No. 2
914928 and DE-A 31 23 894 show the usual arrangement of the tap contacts of a loaded tap selector with equal spacing on the circumference in an insulating cylinder. . The tap contacts subordinate to the same phase are then grouped together on one circumference. However, when the rated voltage rises and the normal number of steps of 11 and 13 steps, when the rated voltage of the transformer exceeds 60 kV, the diameter of the insulating cylinder and the attached structure of the tap selector under load are already increased. Often grows and is uneconomical. In this case, in particular, the requirement for ensuring an impulse withstand voltage of about 300 kV between adjacent contacts causes an increase in the necessary interval.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a load tap selector with a switching contact device of the type described above, which can achieve reliability and expected life even when the rated voltage exceeds 60 kV. It is to provide a load tap selector that can be guaranteed.

[0005]

To achieve the above object, in the present invention, a center between a fixed tap contact provided on a main winding and fixed tap contacts on both sides adjacent to this contact is provided. The spacing or the rotation angle of the contact support is 20 times larger than the center spacing or the rotation angle between the other fixed tap contacts.
% To 60% larger, and both side surfaces of the tap contact provided on the main winding and the side surfaces of both adjacent tap contacts facing this side surface have a square cross section and keep a distance from the surface of the insulating cylinder. And the distance between the protrusions in the direction of the switching movement of the switching contacts is substantially equal to the distance between the other tap contacts.

According to an advantageous configuration of the invention, the electrodes which are placed outside the insulating cylinder and cover the fixing means of the tap contacts have a mutual clearance which is smaller than that of the tap contacts inside the insulating cylinder.

In another configuration of the present invention, the creeping discharge distance starting from the tap contact provided in the main winding is at least 20 times larger than the gap between the tap contacts which are electrically parallel to each other.
% The side surfaces of the tap contacts arranged on both sides of the larger and smaller center distance have bulges facing each other, and the creepage discharge distance depending on this bulge is less than 20% larger than the gap that exists electrically in parallel. Is formed.

According to still another aspect of the present invention, the tap contact swells in a spherical shape only in the peripheral region of the riding portion of the switching contact, and in the central region thereof, the tap contact is concavely recessed so as to have a radius equal to the turning trajectory of the switching contact. There is.

[0009]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 is a connection diagram of a transformer having a main winding and a tap winding, and FIG. 2 is a plan view of an embodiment of the present invention, in which the same parts are designated by the same reference numerals.

The main winding 16 of any phase of the transformer is placed between the high-potential side terminal 23 and the tap contact 1. The tap winding 18 is electrically connected in series to the main winding 16 via the polarity switcher 19, and the voltage extracted by the tap winding 18 depending on the position of the polarity switcher 19 is extracted by the main winding 16. Added to or subtracted from the applied voltage.

The tap contacts 1 to 14 connected to the low-potential side end of the main winding 16 or the tap of the tap winding 18 are
They are arranged in one plane on the inner surface of the insulating cylinder 17 and thus on one circumference. On this circumference, the contact support 15
And the switching contacts 20, 21 and 22 are moved by
These switching contacts switch from one tap contact to the next tap contact without interrupting the load current circuit 24.

The tap contacts 2 to 14 have tap windings 18
Due to the constant coupling to the subordinate taps of each of the taps, a relatively small step voltage is extracted between each of these adjacent tap contacts 2 to 14 even in the event of an impulse withstand voltage. Just join. Therefore, for the gap between the adjacent contacts of each tap contact 2 to 14 and the creeping discharge distance, the size obtained by the conventional normal load tap selector is sufficient.
This also applies when the rated voltage and the operating voltage of the transformer are increased to values greater than 60 kV.

However, the tap contact 1 and the polarity switcher 1
A very large voltage of the entire tap winding 18 is applied between the tap contact 14 and the tap contact 2 depending on the position of 9. Now, when the rated voltage and the operating voltage of the transformer are increased, the voltage of the tap winding 18 also rises, and therefore the tap contact 1
The electrical load in the space between the tap contact 14 and the tap contact 2 also increases.

Unlike the prior art in which the center distances of all tap contacts 1 to 14 have been made equal with respect to the switching contact device, according to the present invention, in the illustrated embodiment, tap contact 1 and tap contact 1 are provided. 14 or tap contact 2
The center spacing between and is 50% greater than the other center spacings.

Nevertheless, in order to be able to select all tap contacts 1 to 14 using one and the same switching contact device, tap contacts 1, 2 and 14
Are the side surfaces facing each other, that is, the tap contact 1
Side faces of the tap contact 2 and the side faces of the tap contact 10 facing the tap contact 1 have projecting portions 25, 26, 2 having angular cross sections.
By including 7 and 28, respectively, the tap contacts 3 to 13 are formed wider. This results in approximately the same dimensions for the side clearances of all tap contacts 1 to 14. Surprisingly, even if the rated voltage and the operating voltage of the transformer are set to values higher than 60 kV, it is necessary to increase only the creeping discharge distance between the tap contact 1 and the tap contact 2 or 14 adjacent to this contact. It is enough.

The illustrated embodiment shows a device with 13 steps. Increasing the center distance from the tap contact coupled to the end of the main winding to the tap contact adjacent to the main winding end is also possible in the case of other number of steps, for example, 11 or 15 steps.

[0017]

[Effects of the Invention] According to the load tap selector of the present invention,
While using the components adopted at the relatively low rated voltage, it has the feature that it can still be applied to the tap selector during load of the relatively high rated voltage. The diameter of the insulating cylinder supporting the contacts can be made relatively small. This feature is obtained by configuring the tap selector under load with different center intervals between tap contacts. Because the switching contacts made of rollers are placed on the left and right sides of the tap contact respectively at the positions on the tap contacts having the normal width, while at the positions on the tap contacts widened, the switching contacts are made. The contact rollers are placed on the surface of the tap contacts rather than beside them.

[Brief description of drawings]

FIG. 1 is a wiring diagram of a transformer having a main winding and a tap winding.

FIG. 2 is a plan view of an embodiment of the present invention.

[Explanation of symbols]

 1-14 Tap contact 15 Contact support 16 Main winding 17 Insulation cylinder 18 Tap winding 20, 21, 22 Switching contact 25, 26, 27, 28 Projection part

Claims (5)

[Scope of utility model registration request] 1. A fixed tap contact (1 to 14) arranged on the circumference of one of the insulating cylinders (17) and connected to a tap, and a circle supported on a common contact carrier (15). One adjustment tap having a main winding (16) and a tap winding (18), which is provided with a roller-made switching contact (20, 21, 22) of three-current branch capable of simultaneously rotating on the circumference. Load tap selector for switching from one to the next tap-all three switching contacts (20,21,22) each lead to the potential of the same tap contact (1 to 14) in its rest position. Together with the switching contacts (20, 2) relative to the contact support (15), one behind the other in the direction of the switching movement.
1, 22) whose radial movement is controlled by fixed tap contacts (1 to 14) which at the same time act as cams: fixed tap contacts (1) provided on the main winding (16) And the center spacing between the fixed tap contacts (2 or 14) on both sides adjacent to this contact, or the rotation angle of the contact support, depends on the center spacing between the other fixed tap contacts (2 to 14) or 20% to 60% larger than the turning angle, the two side surfaces of the tap contact (1) provided on the main winding (16) and the side surfaces of the adjacent tap contacts (2 to 14) facing this side surface, The protrusions (25, 26, 2) having a square cross section and keeping a distance from the surface of the insulating cylinder (17).
7, 28), wherein the distance between the protrusions (25, 28; 26, 27) in the direction of the switching movement is approximately equal to the distance between the other tap contacts (2 to 14). Load tap selector. 2. The electrode, which is placed outside the insulating cylinder (17) and covers the fixing means of the tap contact (1 to 14), has a mutual gap smaller than that of the tap contact (1 to 14). The tap selector according to claim 1. 3. The creeping discharge distance starting from the tap contact (1) provided on the main winding (16) is at least 20% greater than the gap between the tap contacts (1, 2 or 14) that are electrically in parallel. The tap selector according to claim 1 or 2, wherein. 4. The side surfaces of the tap contacts (2 to 14) arranged on both sides of the smaller center distance have bulges facing each other, and the creeping discharge distance depending on the side surfaces is less than 20% of the gap existing electrically in parallel. The tap selector according to any one of claims 1 to 3, which is large. 5. The tap contact (1 to 14) bulges in a spherical shape only in the peripheral region of the riding portion of the switching contact (20, 21, 22), and in the central region thereof, the rotation of the switching contact (20, 21, 22). The tap selector according to any one of claims 1 to 4, wherein the tap selector has a concave surface equal to the radius of the moving track.