JPS6040168B2 - On-load tap changer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an opening/closing mechanism of a vacuum switch in a load tap cutter.

Disconnecting the transformer from the line and changing taps in a no-voltage state every time voltage adjustment is complicated and not responsive, and is especially difficult for smooth operation of power supply and rational operation of electric furnaces, electrolyzers, etc. This results in problems.

For this reason, on-load tap changers have been put into practical use that allow tap changeover while an electrical load remains applied. Incidentally, oil-submerged switches or air-submerged switches have conventionally been used as current switching elements of switching switches for on-load tap changers, but as such switching elements they have excellent shearing ability. It is well known that the use of a vacuum switch with a long contact life is extremely effective in improving the performance of the load tap switching device and saving labor in maintenance.

FIGS. 1a and 1b are explanatory diagrams for explaining the operation of one resistor-type tap switching circuit under load. To achieve its purpose, the on-load tap switching circuit needs to be switched according to a predetermined operating sequence. That is, from the even-numbered taps 2, 4, 6, . . . , the state shown in FIG. 1a to the odd-numbered taps 3, 5, .
・When performing tap switching to the state, the opening/closing order of vacuum switches A to C is to open vacuum switch A, close vacuum switch B, and open vacuum switch C in order to achieve the tap switching state shown in Figure 1b. ,
Conversely, when switching taps from odd-numbered taps to even-numbered taps, vacuum switch C is closed, vacuum switch B is opened, and vacuum switch A is closed in sequence. In this way, the desired purpose can be achieved by intervening the current limiting resistor R during the tap switching transition period, but if it also becomes a three-phase load tap switch, a total of nine vacuum switches are required. Therefore, these arrangements should be considered to occupy less space.

In addition, the opening and closing of the vacuum switch is performed by the driving force from the energy storage device, but from the viewpoint of uniformity of the life of the vacuum switch itself, the energy storage device has the same speed characteristics from the even number side tap to the odd number side tap. , it is also necessary to perform tap cutting from the odd-numbered side taps to the even-numbered side taps. However, since the mechanical load is completely opposite when a vacuum switch transitions from the closed state to the open state and from the open state to the closed state, tap cutting is currently performed with the same speed characteristics. The reality is that this is extremely difficult. In general, the switching speed, which is important for the switching characteristics of a vacuum switch, is greatly influenced by stored energy, load inertia, and mechanical loss. Among these, load inertia in particular changes greatly when changing taps, so we tried to stabilize it. It has the disadvantage that it cannot be obtained. SUMMARY OF THE INVENTION An object of the present invention is to provide a three-phase on-load tap changer that occupies less space and can perform tap changing with the same speed characteristics.

For this purpose, the present invention provides three
The vacuum switches of the groups are arranged in the shape of an equilateral triangle, and a cam body that is driven vertically by the energy storage device is arranged in the center of the vacuum switch. Since it engages with the cam body, it is configured to perform predetermined opening/closing operations for each group, and the cam body has load adjustment according to the vacuum switch group to buffer changes in load during the tap switching process. A container is provided. The present invention will be explained below with reference to FIGS. 2 and 3.

First, FIGS. 2a and 2b show a partially broken and cross-sectional plane and its
- It shows a cross section (however, only a part) according to X-rays.

As shown in the figure, a support 3 is placed in the upper space of the base 32, which has a triangular plane.
The disk-shaped vacuum switch mounting plate 22 is attached through the base 32, and the bearing frame 3 is mounted on the base 32 along the edges of the three sides.
1, and nine vacuum switches 19 forming three groups between the bearing frame 31 and the vacuum switch mounting plate 22,
19a-19c, 20, 20a-20c, 21, 21a
~21c are arranged in a triangular shape.

The vacuum switches 19 to 21 in this case are all of the same standard, and are installed between the bearing frame 31 and the vacuum switch mounting plate 22. For example, to explain the mounting manner of the vacuum switch 19b, its fixed electrode lead 190
is fixed to the vacuum switch mounting plate 22 with a mounting nut 40, while the movable electrode lead 19b2 is supported by the roller punch 18 so as to be movable up and down. That is, a stop plate 37 (vacuum switches 19a to 1
9c) are integrally fixed to each other, and this stop plate 37 and spring receiving plate 38 (common to vacuum switches 19a to 1
(common for 9c). - A punch 18 (common to the vacuum switches 19a to 19c) and a shock absorbing spring 35 are provided as shown in the figure, and
A closing spring 34 is attached on the spring receiving plate 38 to press the movable electrode lead 19Q toward the fixed electrode lead 190. The roller punch 18 is rotatably supported by a shaft 36 attached to a bearing frame 31, and a roller 16 as a cam follower is attached to the other end via a rotating support shaft 17. As described above, the vacuum switches 19 to 21 are attached and arranged in a triangular shape, and the loaf attached to the roller pestle corresponding to each of the vacuum switches 19 to 21 is moved to a predetermined shape of the cam body that is driven in the vertical direction. When the movable electrode lead 19Q is brought into contact with the cam surface of the fixed electrode lead 19b, the roller punch rotates within a predetermined angle range via the roller, and the movable electrode lead 19Q is driven up and down so that it can be separated from the fixed electrode lead 19b.

In the cam body of this embodiment, cam bodies 13a, 14a, and 15a are integrally or integrally attached to a cylinder 12 at equal circumferential angles.

The cylinder 12 is fixed to the upper part of the drive shaft 11, and the drive shaft 11 is supported by a bearing 39 attached to a base 32 so as not to rotate, and is driven up and down by the energy storage device 10.

The developed shapes of the cam bodies 13a, 14a, 15a corresponding to groups are shown in FIG. That is, the cam body 13
a, 14a, and 15a correspond to vacuum switches A, B, and C in FIGS. 1a and 1b, respectively. Therefore, the second
The state shown in FIG. 1B corresponds to the state shown in FIG. If the drive shaft 11 is driven upward in this state, the state shifts to the state shown in FIG. 1a. Incidentally, the magnitude of the mechanical load on the drive shaft 11 is clearly different when driving upward and when driving downward.

As shown in the figure, in the opening/closing mechanism, if the direction of the mechanical load when moving from the closed state to the closed state is negative, then the mechanical load when moving from the closed state to the closed state is the negative direction. The direction of is the positive direction, so the load is exactly the opposite. Moreover, as mentioned above, there are 3 groups of vacuum switches.
The reason for this can be found in the fact that symmetrical driving is impossible. In view of these circumstances, the present invention provides load regulators corresponding to the vacuum switches 19 to 21.

In FIG. 2a, the vacuum switch 19 and the corresponding load regulator 23
Although only the vacuum switches 20 and 21 have the same configuration, the load regulator has a cam body interposed between them to reduce the space occupied by the entire device. It is mounted on the base 32 via the support frame 24 so as to face the corresponding vacuum switches 19 to 21. The load adjuster has a spring therein as a biasing means for adjusting the load, and uses the expansion and contraction of the spring to adjust the load. In this embodiment, the load adjustment spring is expanded and contracted by a roller serving as a cam follower coming into contact with cam bodies 13b, 14b, and 15b that are integrally or integrally attached to the cylinder 12.

To explain the mechanism of the load adjuster 23 corresponding to the vacuum switch 19, the end of the vertically moving village 30, one end of which is attached to one end of the load adjusting spring, is connected to the movable village 25 via a connecting shaft 29. A roller 26 is attached via a spindle 27 to the end of the movable village 25, which is rotatably supported on a spindle 28 attached to a support frame 24. This roller 26 is brought into contact with a cam body 13b having a cam shape opposite to that of the cam body 13a, and the cam body 14b
, 15b and the cam bodies 14a, 15a are also opposite in shape. If you do it like this,
When the load direction on the drive shaft 11 is positive, a negative load should be applied, and conversely, when the load direction is negative, a positive load should be applied. As a result, each vacuum switch group responds to different load patterns between opening-closing operation and closing-closing operation, and the mechanical load changes in combination with changes in the potential energy of the cam body. Uniformity can be achieved and the necessary sequential operation can be obtained. As described above, the present invention
Three groups of vacuum switches (one group is three) are arranged in an equilateral triangular shape along the sides corresponding to the groups, and the cam body located at the center is driven vertically by the energy storage device. The cam followers are engaged with each other, and as the cam body moves up and down, vacuum switches in the same group perform the same opening and closing operations, and between groups, the opening and closing operations are performed in a predetermined sequence. , a load adjuster is provided on the cam body corresponding to the vacuum switch group. Therefore, according to the present invention, it is possible to achieve the effect that tap switching from an even-numbered tap to an odd-numbered tap or from an odd-numbered tap to an even-numbered tap can be performed at the same speed with a small and simple configuration.

[Brief explanation of the drawing]

Figures 1a and b are explanatory diagrams for explaining the tap switching operation for one resistor type load tap switching circuit, and Figures 2a and b are three-phase load tap switching according to the present invention. - of the vessel
FIG. 3, which is a partially cutaway plan view of the cross-section and a cross-sectional view taken along the line X-X, is an example of the cam main body for driving the vacuum switch group in FIGS. 2a and 2b. FIG. 10... Energy storage device, 11... Drive shaft,
13a, 14a, 15a, 13b, 14b, 15b...
...Cam body, 18... Laura village, 19,
19a-19c, 20, 20a-20c, 21, 21a
~21c...Vacuum switch, 23...Load adjuster, 25...Movable punch. Figure 1 Figure 2 Figure 3 Figure 2

Claims (1)

[Claims] 1 Three-phase on-load tap changers are arranged in parallel to form one group. Three groups of vacuum switches are arranged in an equilateral triangle, and the central part of each of the three groups of vacuum switches is At the same time, each cam follower is placed in the center of the three groups of vacuum switches, and is engaged with a cam body that is reciprocated by an energy storage device, so that the same cam follower The vacuum switches within a group perform the same opening/closing operation, and the opening/closing operations between each group are performed in a predetermined sequence order. 1. A load tap changer, characterized in that it has a biased roller and is cam-coupled with a load adjuster that suppresses fluctuations in mechanical load due to reciprocating movement of the cam body.