JP2844515B2 - Tap changer under load - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an on-load tap changer, and more particularly to an on-load tap changer applied to a small transformer such as a pole transformer.

[0002]

2. Description of the Related Art In a large-sized device, a transformer is provided with a tap selector of a load tap changer and a driving device for driving the tap selector. On the other hand, small transformers, especially pole transformers, are inevitably large and heavy when all tap selectors and driving devices are stored in tanks like large machines. And inconvenience in the mounting device. In order to solve this, it is conceivable to configure the tap changer and the drive device so that they can be separated from each other.
For example, Japanese Patent Publication No. 4-7084 discloses this type. The on-load tap switching device is entirely provided inside the transformer tank, and is provided with a cylinder housing a switching switch with an energy storage mechanism using a spring in order from the top, a gear train of a driving system, and a tap selector. ing. The drive shaft is connected by a universal joint in the cylinder. Then, the switching unit is separated and taken out with a universal joint so that inspection, repair, and other operations can be easily performed.

[0003]

When applying the concept of the prior art, in which such a tap selector and a driving device can be separated to each other, to a pole transformer, the separation can be performed, but the switching switch of the driving device can be separated. Is also disconnected from the tap selector, so the transformer must be powered down. Therefore, there is an operation of providing a bypass circuit for the transformer in the distribution line, connecting an emergency mobile transformer to the bypass circuit, and energizing the transformer. In addition, since a drive mechanism used only at the time of tap switching is provided in each of the transformers in spite of being a non-conductive portion, there is a problem that it is an obstacle in reducing the size and weight. SUMMARY OF THE INVENTION It is an object of the present invention to provide a load tap changer which can detachably connect a power storage device for driving the tap selector to a tap selector, and can operate without power failure of a transformer even when the power storage device is removed. It is in.

[0004]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a plurality of fixed contacts connected to a tap winding of a transformer, and a movable contact slidably contacting the fixed contacts. A tap selector comprising a current-limiting resistor connected to the contact and the movable contact and rotatably supported by the transformer, and a tap selector mounted above the tap selector and manually operated by a spring. A power storage device that releases the stored energy and intermittently rotates the drive shaft, and detachably connects the drive shaft of the power storage device and the tap selector to form a load tap changer. It was done.

[0005]

In the above construction, the current limiting resistor is connected to the movable contact sliding with the fixed contact to limit the short-circuit current between taps by the current limiting resistor. It has the function of a blocking unit. Therefore, the energy storage device having no current-carrying portion may be always mounted on the transformer, but can be mounted only at the time of tap switching.

[0006]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing a first embodiment of a load tap changer according to the present invention; FIG. 1 shows a pole transformer,
A tap selector 4 to which a tap lead of a transformer is connected is fixed to a tank inside a transformer main body 1 and a tank 2 containing insulating oil. Further, an energy storage device 3 is detachably connected between the tap selector 4 and the drive shafts 25-42 above the tank 2 with the lid removed. FIG. 2 shows the energy storage device 3
Is removed and the tank lid 5 is attached. In each of the states shown in FIGS. 1 and 2, the transformer is in a load state.

Next, the above-described energy storage device 3 and tap selector 4
Will be described with reference to FIG. The energy storage device is composed of components indicated by reference numerals 11 to 26. 11 is a handle,
A plate-like lever 13 projecting in a direction perpendicular to the axis is fixed to a first drive shaft 12 which is the axis of the handle 11. Further, a disc 14 is fitted to the lower end of the shaft 12 via a roller bearing, and is rotatable with respect to the shaft 12 and is supported by a snap ring so as not to come off. A single drive pin 15 is inserted and fixed on the outer peripheral side of the disk 14 by projecting upward and downward from the disk 14, and when the shaft 12 is turned, the lever 13 abuts on the upper protrusion of the drive pin 15. Have been. On the other hand, a plate-like piece 16 is fitted in the middle of the lower protruding portion of the drive pin 15 via a roller bearing. A coil spring 17 is mounted between the piece 16 and a fixed frame (not shown) in a direction perpendicular to the axis of the drive pin 15.

Further, the lower end of the drive pin 15 is engaged with a disk 18 disposed below the drive pin 15. This disk 18
A long hole 18a of a concentric arc extending 180 degrees at the central angle is provided on the outer peripheral side of. The distal end of the drive pin 15 described above is loosely fitted into the elongated hole 18a. This disk 1
A second drive shaft 19 extending downward is fitted and fixed to the center of 8, and a disk Geneva driver 20 is fitted and fixed to its lower end. One Geneva pin 20a protrudes from the outer peripheral side of the Geneva driver 20, and the Geneva pin 20a is located at a position 180 degrees from the center point of the long hole 18a of the disk. The adjacent Geneva gear 21 and the pin 20a mesh with each other. The number of teeth of the Geneva gear 21 is set so that the driver 20 rotates 60 degrees per rotation.

A small gear 23 is provided at the lower end of a third drive shaft 22 extending downward from the center of the Geneva gear 21. The large gear 24 meshed with the small gear has twice the number of teeth as the small gear, so that the small gear rotates １ ／ for one rotation. Further, a fourth drive shaft 25 extending downward is attached to the large gear 24, and a pin 26 is attached to a lower end thereof so as to project in a direction perpendicular to the axis. Although not shown in FIG. 3, the first and
The fourth to fourth drive shafts 12, 19, 22, 25 are supported by a frame supporting the above-described drive system members via roller bearings. This frame is mounted on a frame of a tap selector 4 described later, and is concentrically incorporated by a positioning pin.

Next, the tap selector shown in FIGS. 3, 4 and 5 will be described. A ring-shaped disk base 3 made of an insulating material is placed on a lower base 30 fixed to the inner wall of the tank 2.
1 is fixed. On this disk base 31, six fan-shaped fixed contacts 32a to 32f are circumferentially spaced. As shown in FIG. 4, the fixed contacts 32 have contacts 32a, 32b, and 32c arranged with a predetermined gap therebetween, and corresponding contacts 32d, 32e, and 32f also have a predetermined gap. It is arranged. Note that the numbers (1 to 6) written on the contacts in this figure indicate tap numbers.

On the other hand, a rotating portion having a movable contact is mounted on the lower base 30 inside the above-mentioned ring-shaped fixed contact. First, a rectangular movable base 33 made of an insulating material is rotatably disposed on the lower base 30, and a shaft hole 33a having a pin groove with which a drive shaft described later is engaged is formed at the center of the rotation shaft. And 4 on the base 33
The movable contacts 34, 35, 36, 37 are attached. One end of each movable contact has a movable base 3
3, a strip-shaped contact bracket 38 having the other end protruding from the base and a contact piece 39 made of a spring plate fixedly sandwiching the projecting portion of the bracket from above and below. A spherical contact provided at the distal end of 39 is in elastic contact with the front and back surfaces of the fixed contact 32. And, among these movable contacts, the contacts 34 and 35 are adjacently juxtaposed,
The interval A is set to be larger than the gap B between the fixed contacts, so that one movable contact always contacts one of the fixed contacts when straddling between adjacent fixed contacts by rotation. I have. The contacts 36 and 37 on the opposite side are also arranged in the same positional relationship as described above.

Further, two current limiting resistors 40 and 41 are mounted on the movable base 33. Then, as shown in the connection diagram of FIG. 6, the current limiting resistor is connected between the movable contact 34 and the opposite movable contact 36 and between the movable contact 34 and the same contact 35 and the opposite contact 37. They are connected by conductors, and furthermore, the contacts 34 and 37 are connected by a cable to constitute a breaking part of the switching switch circuit.

A fifth drive shaft 42 is attached to the above-described rotating portion as shown in FIG. A pin 43 is inserted into the lower end of the fifth drive shaft 42 so as to project in the direction perpendicular to the axis, and is engaged with the pin groove of the center hole 33 a of the movable base 33. Further, an axial pin groove 42a for connecting the fourth drive shaft 25 of the energy storage device is formed at the upper end. Further, a detent disk 45 is fixed to the fifth drive shaft, and a plurality of cutouts corresponding to the number of tap switching operations are provided on the outer peripheral portion (in this example, five notches are provided).
Places).

On the other hand, a stopper 44 made of a strip-shaped leaf spring is fixed to the stationary side, and its tip engages with the notch to lock the rotating part at a desired tap position. . When the energy storage device 3 is placed at the time of tap switching, the tip of the stopper 44 is pushed down by the projection pin provided on the energy storage device, and the lock is released.
In addition, both ends of the notch of the rotation preventing disk 45 are configured to bend the disk so as to protrude downward, thereby restricting the rotation angle of the rotation unit to a predetermined range. Although not shown in FIG. 3, the fifth drive shaft 42 of the tap selector 4
Are supported on the frame via roller bearings.

Next, the operation will be described. In the loaded state, the lid of the pole transformer is removed, and as shown in FIG.
Is released, the lock is released, and the fifth drive shaft 42 of the tap selector 4 and the fourth drive shaft 25 of the energy storage device 3 are concentrically connected by the pin 26 by being guided by the positioning pin. Therefore, when the handle 11 of the energy storage device 3 is manually turned, for example, clockwise, the lever 1 of the first drive shaft 12 is turned.
3 abuts against the drive pin 15 of the disk 14. Further handle 1
1 is rotated in the same direction to rotate the disk 18, the second drive shaft 19 and the Geneva driver 20 by 180 degrees. At this time, since the driving pin 15 moves while pulling the spring 17, the pulling force is accumulated.

When the drive pin 15 moves by 180 degrees and exceeds the dead center of the spring 17, the stored energy of the spring is converted into a rotational force, and the disk 18, the second drive shaft 19 and the Geneva driver 20 are rapidly turned. Move. With this rotation, the pin 20a of the Geneva driver 20 meshes with the Geneva gear 21, and the third drive shaft 22 rotates 60 degrees by the shifting action of the Geneva mechanism. Even when the disk 18 is rapidly rotated and the drive pin 15 returns to the initial position (the position of the spring 17 in the most contracted state), the disk 18 is additionally rotated together with the Geneva driver 20 by its inertia. Move. However, since the drive pin 15 is inserted into the elongated hole 18a with play in the circumferential direction, the disk 1
Due to the extra rotation of 8, the spring 17 is not pulled.
Further, since the long hole 18a is provided in the range of 180 degrees in the central angle, the inertial rotation of the disk 18 does not exceed 180 degrees, and therefore the Geneva pin 20a further moves the Geneva gear 2
Prevents meshing with 1.

The rotation angle of the third drive shaft 22 is converted into half by gears 23 and 24, and the fourth drive shaft 25
Rotates 30 degrees. Therefore, the turning section of the tap selector 4 is driven, and turns 30 degrees counterclockwise.

As described above, the movable contact can be turned by 30 degrees by operating the handle of the energy storage device 3 to switch to the desired tap position. Further, since a current limiting resistor is connected to the movable contact, it has a switching switch function at the time of tap switching. After the tap switching operation is completed, the load operation of the transformer can be performed regardless of the presence or absence of the energy storage device 3. When the switching operation is completed and the energy storage device 3 is pulled up, the rotation preventing mechanism provided on the fifth drive shaft 42 of the tap changer 4 operates and locks.

Next, another embodiment of the present invention will be described. In the above-described embodiment, the Geneva gear 21 of the Geneva mechanism has the number of teeth that the Geneva driver 20 rotates by 60 degrees per rotation, but this is the number of teeth that the Geneva driver 20 rotates by 30 degrees per rotation. Can also be used. With this configuration, the Geneva gear 21 has a large diameter, but the reduction gear including the small gear 23 and the large gear 24 is omitted, and the Geneva gear 21
Of the fifth drive shaft 22 of the tap selector 4
2 can be directly connected.

In this case, in addition to the simplification of the structure, the turning direction of the energy storage device and the rotation direction of the tap selector become the same direction. There is an advantage that the turning direction is clarified.

Next, another embodiment of the present invention will be described. As shown in FIG. 7, the tap selector 4 is mounted inside the pole transformer. This tap selector 4 is different from the above-described embodiment in that it has no fifth drive shaft 42. A hole 5a is formed in the tank lid 5 so that the blind lid 5
b. FIG. 8 shows a state where the energy storage device 4 is mounted on the transformer. Blind lid 5b as shown in the figure
And the energy storage device 3 is fixed to the lid 5 and the fourth drive shaft 25 can be connected to the tap selector 4.

According to this embodiment, since the energy storage device 3 can be mounted while the transformer lid 5 is mounted, not only the speed of the mounting operation but also the intrusion of dust into the tank can be suppressed. Further, if a space for mounting the tap selector can be secured, the present invention can be applied to an existing transformer. Further, it is a matter of course that the connection structure between the energy storage device and the tap selector can be one that can be attached and detached in the axial direction, such as a flange coupling system.

[0023]

As described above, according to the present invention, since the energy storage device can be mounted on the transformer in the load operation state only when the tap is switched and the tap switching operation can be performed, the pole transformer can be operated. If it is adopted for a standard type device as in the above, it has a practical effect that it can be used as a common tool for many transformers.

[Brief description of the drawings]

FIG. 1 is a front view of a transformer equipped with a tap changer showing one embodiment of the present invention.

FIG. 2 is a front view of the transformer showing a state in which the energy storage device is removed.

FIG. 3 is a perspective view showing an energy storage device and a tap selector.

FIG. 4 is a plan view of a tap selector.

FIG. 5 is a vertical sectional view of a tap selector.

FIG. 6 is an electric circuit diagram of a tap winding and a tap selector.

FIG. 7 is a front view of a transformer showing another embodiment of the present invention.

8 is a front view of the transformer shown in FIG. 7 with the energy storage device mounted thereon.

[Explanation of symbols]

 Reference Signs List 3 Energy storage device 4 Tap selector 25 Drive shaft 32 Fixed contact 34, 35, 36, 37 Movable contact 40, 41 Current limiting resistor

────────────────────────────────────────────────── ─── Continued on the front page Examiner Tomohiro Sakai (56) References JP-A-59-189518 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) H01F 29/04

Claims (1)

(57) [Claims] A fixed contact connected to a tap winding of a transformer, a movable contact slidably contacting the fixed contact, and a current limiting resistor connected to the movable contact are provided. A tap selector comprising a rotating portion rotatably supported by the transformer; and an intermittent rotation of the drive shaft mounted above the tap selector by manually releasing energy stored in a spring. A tap changer under load, comprising: a power storage device for moving the power storage device; and a drive shaft of the power storage device and a tap selector are detachably connected to each other.