BG65361B1 - Switch without excitation for power transformers - Google Patents

Abstract

The no-excitation transformer is applied in power transformers for switching any tappings from the regulation winding for a transformer excluded from the network. It has simplified and stable design, with facilities for the adjustment of different modifications, satisfying all technical requirements. The supporting insulation structure is made of a large (1) and a small (2) insulation sector, fitted between an upper (3) and lower (4) metal shield. On two tiers of the large insulation sector (1), contact elements (5) are arranged in a fixed manner. Coaxially to the insulation sectors (1 and 2), an inner insulation shaft (7) with contact bridge (8), with an arm (9) are mounted in it upper part, and a contact sector (10) in its lower part, and external insulation shaft (6) to which, by lugs (12), a second arm (11) is fitted. On both arms (9 and 11) mobile contact elements (13 and 15) are fitted. As an embodiment for redoubled rated current there are two large insulation sectors (1) and atwo-arm mobile contact system. In an embodiment for linear regulation of the small sector (2), current leads (30) with contact elements (31) are fitted. Only an external insulation shaft (6) is used having rings (28) with arms (29) mounted on it, over which the mobile contact elements (13) are found.

Description

Technical field

The invention relates to a switch of deviations of power transformers at excitation transformer for the purpose of regulation of voltage. These non-excitation switches are sometimes called switches.

BACKGROUND OF THE INVENTION

A non-excitation switch [1] is known, comprising fixed odd and even contact elements arranged on two floors connected to the deflections of the winding of a power transformer. The movable odd and even contact elements are secured by supports each to a parallel actuating insulation rail. The beams located below each other have cylindrical necks in which a connecting U-shaped conductive element is mounted. At the end of each of the actuating insulation rails, one Maltese sector, functionally connected with double translation, is installed.

The disadvantage of the known switch without excitation is that it is unstable because the two insulation rails are not coaxially arranged and the connection between them is through relatively short U-shaped conductors. The fixed contact elements are mounted on insulating racks occupying only one sector. This also makes the insulating supporting structure unstable and requires additional measures to strengthen it, which complicates the structure. Another disadvantage is that the so-called linear control cannot be realized, whereby the deviations of the control coil are connected in series from one output.

SUMMARY OF THE INVENTION

It is an object of the invention to provide an excitation switch having a simple and stable load-bearing insulating structure and coaxially arranged insulating drive shafts. Also, with a unified supporting structure it can realize linear regulation.

The problem is solved by a non-excitation switch comprising a support structure of insulating elements with fixed contact elements and movable contact elements mounted on actuating shafts connected to the Maltese sectors, according to the invention the support structure consists of an interposed upper shield and a lower metal shield a large insulation sector on which fixed contact elements are mounted; and a small insulation sector on which currents are mounted in linear regulation water. Mostly on the axis of the insulation sectors are an external insulation shaft and coaxially inside it an insulation shaft, with movable contact elements mounted thereon. With linear adjustment, there is only an external insulation shaft. A contact axle with a shoulder at one end and a contact section at its other end is mounted on the insulation shaft. A second arm is secured to the outer insulating shaft through the ears. On both arms are movable contact elements, with the contact elements of the second arm touching the contact sector.

In the case of linear adjustment of the outer insulation shaft, rings with shoulder arms are mounted on which movable contact elements are located. Short-circuited contact elements are mounted on the electrical terminals attached to the small insulation sector, which contact the rings. As an option for doubling the rated current, the small insulation sector is replaced by a second large insulation sector with fixed contact elements mounted on it. Two shoulder arms with movable contact elements are mounted opposite to the contact axle of the inner insulation shaft.

For long structures, such as those required for higher voltage transformers, the large insulation sector and the small insulation sector are connected by means of insulating disks or other similar insulation elements fixed by insulation bolts.

An advantage of the excitation switch according to the invention is that it isolates

65361 Flange structure is a frame of stable elements, which gives great stability in a simplified structure. The coaxially positioned shafts are solidly fixed and do not influence each other when rotating. Another advantage is that linear adjustment can be achieved in a unified construction. The advantage is that even with a unified design, a double-current excitation switch can be made. These advantages are available in different applications of the switch without excitation: attachment to the transformer cover or bell; attachment to the active part of the upper and lower drive transformer; horizontal position.

Explanation of the annexed figures

Exemplary embodiments of an excitation switch according to the invention are shown in the accompanying drawings, of which:

Figure 1 is a longitudinal section through a single-phase switch without excitation for attachment to the transformer cover;

FIG. 2 is a cross-sectional view above the reinforcing insulation ring of FIG. 1;

3 is a cross-sectional view above the upper floor of the contact system of FIG. 1;

4 is a cross-sectional view above the lower floor of the contact system of FIG. 1;

Figure 5 is a longitudinal section view of one phase of a coupled contact system;

6 is a cross-sectional view of the contact system of FIG. 5;

Figure 7 is a longitudinal section view of a three-phase switch without excitation for linear adjustment;

8 is a cross-sectional view above the contact system of FIG. 7.

Examples of carrying out the invention

Figures 1,2,3 and 4 show a single-phase switch without excitation for ± 2 steps of a known winding of a power transformer with a gap in the middle. The insulation structure consists of a large insulation sector 1 and a small insulation sector 2, mainly made of insulation cylinders. They are secured between the upper metal shield 3 and the lower metal shield 4. Three fixed contact elements are arranged on two floors of the large sector 1 5. Coaxially on the small sector 2 between the upper metal shield 3 and the lower metal shield 4 are mounted an external insulating shaft 6, in this case made of pipe, and an internal insulating shaft 7, in this case made of two insulating rails. A contact axle 8 with a shoulder 9 at the top and a contact section 10 at the bottom are mounted to the insulation shaft 7. A pair of movable contact elements 13 with contact springs 14 are mounted on the upper insulating shaft 6 on the outer insulating shaft 6. Similar are the contact elements 15 with contact springs located on the lower arm 11. From the inner end of the movable ones contact elements 15 are contacted on sector 10. The upper metal shield 3 is secured to a circular flange 16, which is mounted on the cover of a non-shown power transformer. The upper end 17 of the inner insulating shaft 7 is connected to the upper Maltese sector 18. The upper end 19 of the outer insulating shaft 6 is connected to the lower Maltese sector 20. The two Maltese sectors 18 and 20 are actuated alternately by double translation 21. The double translation 21 is connected to a shaft 22 of a known worm gear 23. A worm shaft 24 is coupled to a known actuator not shown. The bearing head has a position index 25.

In the case of longer switches without excitation, the two insulating sections 1 and 2 are secured by insulating disks 26 secured by insulating bolts 27.

The presented design of two coaxially positioned drive insulation shafts 6 and 7 allows the construction of a compact switch without double-current excitation (Figs. 5 and 6). The position designations are the same as in Figures 1, 2, 3 and 4. The small insulation sector 2 is replaced by a mirror-mounted large insulation sector 1. By connecting the single-digit fixed contact elements 5 in parallel, the rated current of the switch without excitation is increased.

An exemplary embodiment of an excitation switch for four linearly arranged steps is shown in FIG. 7 and 8. The construction is unified with that of FIG. 1. The difference is that there is only an external insulation shaft 6 connected

65361 Bl through its upper end 19 only to the lower Maltese sector 20. To the insulating shaft 6 on three floors for one of three phases are attached one ring 28 with arm 29 on which movable contact elements 13. The general current terminal 30 for each phase is mounted is attached to the small insulation sector 2. Short contact elements 31 are mounted on the current terminal 30, which contacts the ring 28.

The action of the excitation switch according to the invention is as follows.

The worm shaft 24 (Figures 1, 2, 3, 4) rotates, for example, clockwise, and the worm gear 23 rotates the shaft 22 and the double translation 21 counterclockwise. In this case, the upper Maltese sector 18 rotates one step clockwise (Fig. 3) and the upper movable contact element 13 is moved through the inner shaft 7 from the middle fixed contact element 5 of the terminal movable contact in a clockwise direction. In the next cycle of operation, the lower movable contact member 15 is rotated one step through the outer shaft 6 in an analogous manner. All positions can be sequentially covered. The circuit is not interrupted in successive steps, since the lower movable contact member 15 is continuously connected to sector 10.

The switch without excitation of FIG. 5 and 6, with each step moving the respective coupled movable contact system.

The excitation switch of FIG. 7 and 8 there is only an external drive shaft 6 and a lower Maltese sector 20. In each cycle, the shaft 6 rotates one step and rotates the movable contact element at the corresponding angle to a neighboring fixed contact element 5. The contact elements 31 rub against the disks 28 and the current circuit is maintained.

The non-excitation switches according to the invention are mounted in the vertical position of the transformer cover, and bell type transformers are also possible. In other embodiments, it can be mounted on the active part of the upper or lower drive transformer. Horizontal mounting options are also available.

Claims (5)

Claims A non-excitation switch comprising a supporting structure of insulating elements with fixed contact elements and movable contact elements mounted on actuating shafts connected to the Maltese sectors, characterized in that the supporting structure consists of fastened between the upper metal shield (3) and a lower metal shield (4) a large insulation sector (1) on which fixed contact elements (5) and a small insulation sector (2) are mounted on which, at linear adjustment, current terminals (30) are mounted , and mainly on the axis of the insulation sectors (1, 2) there is an external insulation shaft (6) and coaxially inside it an insulating shaft (7) with movable contact elements (13, 15) mounted thereon, with linear adjustment having only external insulation shaft (6). A non-excitation switch according to claim 1, characterized in that a contact bridge (8) is mounted on the inner insulation shaft (7) with a shoulder (9) at one end and a contact section (10) at the other end at the outer an insulating shaft (6) secures a second arm (11) through the ears (12) and the movable contact elements (13, 15) are mounted on both arms (9, 11), with the contact elements (15) on the second arm (11) are in contact with the contact sector (10). An excitation switch according to claim 1, characterized in that, with linear adjustment of the outer insulation shaft (6), rings (28) with arms (29) are mounted, on which the movable contact elements (13) are located, and current terminals (30) attached to the small insulation sector (2) are fitted with short contact elements (31) which contact the rings (28). Non-excitation switch according to claims 1 and 2, characterized in that the small insulation sector (2) is replaced by a second large insulation sector (1) with fixed contact elements (5) mounted thereon, and to the contact bridge (8) ) are mounted opposite to each other on two arms (9, 11) with movable contact members (13,15). 65361 Bl An excitation switch according to claims 1,2 and 3, characterized in that in the case of long structures for higher voltages, the large insulation sector (1) and the small insulation sector (2) are connected via insulating disks (26). ) or other similar insulation elements fixed by insulation bolts (27).