JPH10116742A - On-load tap changer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the radius of a circle for installing a fixed contact part by setting the opening of an insulated drive tube such that a second movable contact can project and can turn prior to a first movable contact. SOLUTION: A first tubular insulated drive shaft and a second solid insulated drive shaft are arranged coaxially and the first drive shaft is provided with an opening through which a second movable contact M2 can project. The opening is dimensioned such that the second movable contact M2 can turn forward and reversely prior to a first movable contact M1 and thereby the resistive contact M2 precedes at all times. Only the second movable contact M2 connected in series with a current limit resistor R and a second vacuum valve V2 is switched prior to quick break operation and then the first movable contact M1 and two vacuum valves V1, V2 are broken quickly in a specified order. Since three contacts must be switched when a tap selector moves between fixed contacts, fixed contact parts T1 , T0 , T8 can be reduced in the radial direction resulting in total compaction.

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 of a transformer, and more particularly to an improvement of an on-load tap changer using one current limiting resistor and two vacuum valves.

[0002]

2. Description of the Related Art An on-load tap changer for switching a tap winding of a transformer using two movable contacts, one current limiting resistor and two vacuum valves has already been disclosed in JP-B-61-4584.
5 and JP-A-2-128410.

[0003] In these systems, a movable contact connected in series to a current limiting resistor and a vacuum valve, and a movable contact connected in series to a vacuum valve are mechanically fixed. The movable contact which comes in contact with the adjacent fixed contact connected to the first contact differs depending on the switching direction. In any case, the switching operation can be performed by selecting the adjacent fixed contacts one after another by a rapid cutting operation.

FIGS. 16 and 17 show Japanese Patent Publication No. 61-458.
1 shows a configuration of a system disclosed in Japanese Patent Publication No. 45-45. 16 and 17, reference numerals 61 to 64 denote fixed contacts connected to taps 65 to 68 derived from the tap winding 69.

Reference numeral 70 denotes a contact carrier.
0, two roller contacts 73 and 74 that perform switching operation while rolling with respect to the fixed contacts 61 to 64 have springs 80 and 74, respectively.
It is elastically held through 81.

Further, each roller contact 7 is attached to the contact carrier 70.
Vacuum switches 75 and 76 are provided corresponding to the contact switches 3 and 74, respectively.
9 are connected to the corresponding roller contacts 73 and 74, respectively. The fixed contact side of one vacuum switch 75 is connected to the current branch point 71, and the other vacuum switch 76
Is connected to a current branch point 71 via a switching resistor 77 provided in a current branch circuit 72, and an energizing circuit 82 is connected to the current branch point 71.

Next, each state of the switching operation of the tap changer having such a configuration will be described with reference to FIGS. 16 (a) to (c) and FIGS. 17 (a) to 17 (a).
Description will be made in the order of (f). FIG. 16A shows a state in which the transformer load current flows through the tap 66, the roller contact 73, and the vacuum switch 75, and the fixed contact 62 of the tap 66 is selected.

In FIG. 16B, one vacuum switch 76 is opened. FIG. 16C shows that the roller contact 74 has a tap 66.
Is separated from the fixed contact 62. FIG. 17A shows that the roller contact 74 reaches the fixed contact 63 of the tap 67.

In FIG. 17B, when the vacuum switch 76 is closed, a short circuit is formed between the taps 66 and 67, and a circulating current limited by the switching resistor 77 flows. The load current is still at tap 66-roller contact 7
3. Flow through the circuit of the vacuum switch 75.

FIG. 17C shows that when the vacuum switch 75 is opened, the transformer load current moves to the circuit of the tap 67, the roller contact 74, and the vacuum switch 76. FIG.
In (d), the roller contact 73 is separated from the fixed contact 62 of the tap 66.

FIG. 17E shows that the roller contact 73 has the tap 6
7 reaches the fixed contact 63. In FIG. 17F, when the vacuum switch 75 is closed, the transformer load current moves to the circuit of the tap 63, the roller contact 73, and the vacuum switch 75, and the one-tap switching is completed. That is, the four contacts of the roller contacts 73 and 74 and the vacuum switches 75 and 76 are opened and closed during the one-tap switching quick-cut operation. In the above-described switching operation, the roller contact on the resistance side operates in advance, but in the reverse switching, the other roller contact operates in advance.

FIG. 18 shows the structure of the system disclosed in Japanese Patent Application Laid-Open No. 2-128410. FIG.
In FIG. 8, a load tap changer 91 is provided with two changeover contacts 96 and 99 corresponding to a tap contact 93 derived from a tap winding 92. 96, a current limiting resistor 95 and a vacuum switch 97 are connected in series, and the other contact 99 is connected to a vacuum switch 98.
And these vacuum switches 97 and 98 are connected to the sliding contact 102 with the fixed contact side common, and this sliding contact 1
02 is connected to a network terminal 92 via a slip ring 103.

In the tap changer having such a structure, four contacts are opened and closed during one quick disconnection operation similarly to the tap changer shown in FIG.
Different contacts operate in advance in forward and reverse switching.

[0014]

In such a conventional load tap changer, fixed contacts connected to taps derived from tap windings are arranged on the same plane according to the number of taps. The angle between the contacts is 360 ° / n (the number of fixed contacts).

In general, assuming that nine fixed contacts are arranged at equal intervals along the circumference, the angle between the contacts is 40 °.
Therefore, in order to switch between the fixed contacts by the tap changer described above, it is necessary to open and close two movable contacts and two vacuum switches in the order of tap switching, and the two vacuum switches involve current interruption. Therefore, it is necessary to secure time required for arc extinguishing.

[0016] For this reason, in order to perform the operation in the range of 40 ° in the above-described example, it is necessary to dispose the fixed contact portion at a position where the radius is increased, so that an increase in size is inevitable.
The present invention has been made in view of the above circumstances, and when the fixed contacts connected to the tap windings are arranged at regular intervals along the circumference, the radial direction can be reduced, and thus the entirety can be reduced. It is an object of the present invention to provide an on-load tap changer capable of compactly integrating the tap taps.

[0017]

According to the present invention, in order to achieve the above object, a load tap changer is constituted by the following means. The invention corresponding to claim 1 includes a plurality of fixed contacts connected to taps of a transformer tap winding, a first load current energizing movable contact that contacts the fixed contacts, and a contact with the fixed contacts. A second movable contact for supplying a circulating current when a short circuit occurs between taps;
A first vacuum valve is connected to the movable contact, and a current limiting resistor for suppressing a circulating current and a second vacuum valve are connected in series to the second movable contact, and the first and second movable contacts are connected. Are connected to the same fixed contact to form a parallel circuit, and when performing tap switching, the second movable contact connected with a current-limiting resistor that suppresses circulating transfer is switched in the same forward direction switching and reverse direction switching. In the on-load tap changer configured to always perform a switching operation before the first energizing movable contact and to contact a fixed contact connected to an adjacent tap, a driving side driving unit and A power storage device for storing static energy for causing the first movable contact to perform a quick disconnection operation by a driving side driving unit; and a predetermined static energy stored in the power storage device connected to the driving side driving unit for driving. During operation until the second A second intermittent gear mechanism for moving a movable contact to an adjacent fixed contact, and a first movable contact that is connected to a driven side of the energy storage device and that releases the static energy stored in the energy storage device to quickly move the first movable contact. A first intermittent gear mechanism that performs a cutting operation, and a cam mechanism that is connected to a driven side of the energy storage device and that opens and closes the first and second vacuum valves in a predetermined order by releasing the static energy. .

According to a second aspect of the present invention, in the first aspect, the first and second intermittent gear mechanisms for driving the first and second movable contacts are provided with one Geneva driver and a plurality of teeth. And a pair of Geneva mechanisms provided with a Geneva gear.

According to a third aspect of the present invention, in the first aspect, first and second insulated drive shafts are provided on the driven side of the first and second Geneva gears, and the insulated drive shafts are respectively provided. Attach and fix the first and second movable contacts,
The fixed contact can be sequentially selected with the rotation of the Geneva gear, and the first insulated drive shaft is coaxially arranged with a tubular shape and the second insulated drive shaft with a solid shaft. The shaft is provided with an opening through which the second movable contact can protrude, and this opening is large enough to allow the second movable contact to rotate ahead of the first movable contact in both forward and reverse directions.

According to a fourth aspect of the present invention, in the invention according to the second aspect, a groove cam is directly connected to a driven portion of the first Geneva driver, and the first and second vacuum valves are opened and closed with the groove cam. And two grooves for performing a predetermined operation in accordance with the first movable contact and the tap switching sequence.

With this configuration, only four contacts can be opened and closed in a narrow fixed contact tube in the related art, whereas only four contacts can be opened and closed. The direction can be reduced, and the whole can be compacted.

[0022]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view showing a specific configuration of an embodiment of a load tap changer according to the present invention.
In FIG. 1, reference numeral 1 denotes an electric motor, and a pinion 2 is directly connected to a rotating shaft of the electric motor 1. Reference numeral 3 denotes a gear which is attached to the shaft 5 and which meshes with the pinion 2 to transmit the torque of the electric motor 1. A pin 6 is attached to the gear 3 at an appropriate position slightly deviated from the central axis toward the shaft end. At the same time, a pin 9 is attached at an appropriate position on the peripheral surface opposite to the pin 6.

One end of a shaft 5 is provided with one end of an arm 4 which is rotated by the rotation of the gear 3 by being pressed by a pin 6. One end of a tension spring 7 is attached to the other end of the arm 4. The other end is supported by a fixing member (not shown) by a fulcrum pin 8. The tension spring 7 accumulates a spring force by the rotation of the arm 4 and instantaneously releases its energy when a predetermined accumulated amount is reached.

Further, a segment 20 having a pin engaging portion is attached to the other end of the shaft 5.
And a driver 22 is attached to one end of an insulated drive shaft 24 disposed in the same axial direction as the shaft 5. This driver 22
A pin 21 that engages with the engaging portion of the segment 20 is attached to the, and a pin 23 is attached to the opposite side of the pin 21.

A groove cam 30 is attached to the other end of the insulating drive shaft 24. The groove cam 30 has a first vacuum valve 31 (V1) and a second vacuum valve 32 (V1).
A cam groove 35 (for main use) and a cam groove 36 (for resistance) for opening and closing 2) via drive levers 34 and 33 in a predetermined order are formed respectively.

In this case, when the pin 21 is engaged with the engaging portion of the segment 20 and the driver 22 is rotated, the torque is transmitted to the insulating drive shaft 24 and the groove cam 30 is rotated. Drive levers 33 and 34 that engage with 36
Moves to the upper displacement and the lower displacement of the cam groove,
Each of the vacuum valves 32 and 31 is configured to be able to open and close.

On the other hand, 200 is the second movable contact 44 (M
2) is a second intermittent gear mechanism for transmitting torque for driving the second driving mechanism. The second intermittent gear mechanism 200 is attached to one end of the insulated driving shaft 11 and is connected to the pin 9 attached to the gear 3 described above. And a Geneva gear 10 that is driven in mesh with the gear. An arm 4 is provided at the other end of the insulating drive shaft 11.
2 is attached to one end of the second movable contact 44 at the other end.
(M2) is attached.

In this case, when the rotation of the Geneva gear 10 is transmitted to the arm 42 via the insulated drive shaft 11, the second movable contact 44 (M2) attached to the arm 42 is centered on the insulated drive shaft 11. And the switching operation between the fixed contacts 46 can be performed.

100 is a first movable contact 45 (M
1) is a first intermittent gear mechanism for transmitting a torque for driving 1). The first intermittent gear mechanism 100 is provided at an end of a pipe-shaped insulating shaft 26 coaxially arranged with the insulating drive shaft 11. Pin 2 attached and attached to driver 22
3 and a Geneva gear 25 that rotates when the torque of the driver 22 is transmitted. Insulated shaft 2
6, one end of an arm 43 is attached to the other end, and a first movable contact 43 (M1) is attached to the other end.

In this case, when the rotation of the Geneva gear 25 is transmitted to the arm 43 via the insulating shaft 26, this arm 4
The first movable contact 43 (M1) attached to the rotating member 3 rotates around the insulating shaft 26 so that the switching operation between the fixed contacts 46 can be performed.

In the drawing, reference numeral 40 denotes a current collecting ring that contacts the second movable contact 44, and reference numeral 41 denotes a current collecting ring that contacts the first movable contact 43. Next, the switching operation of the on-load tap changer configured as described above will be described with reference to FIGS.

FIG. 2 shows the circuit in the switching operation process in order, and FIG. 3 shows the switching sequence. In FIG. 2, TW is a tap winding, T1 and T2 are adjacent taps, M1 is a first movable contact of a tap selector,
M2 is the second movable contact, V1 is the first vacuum valve, V2
Indicates a second vacuum valve.

When switching from tap T1 to T2 (1) Tap selectors M1 and M2 select tap T1,
The first vacuum valve V1 is closed, and the second vacuum valve V2 is closed.
Indicates a state where the circuit is open. The load current is T1-M
1-V1. (2) The second movable contact M2 of the tap selector is the tap T1
To tap T2. (3) The second vacuum valve V2 is closed, and the taps T1, T
A short circuit between the two is formed, and a circulating current suppressed by the current limiting resistor R flows. (4) The first vacuum valve V1 is opened and the load current is reduced to T1.
From the side circuit to the T2 side circuit. (5) The first movable contact M1 of the tap selector is the tap T1.
To tap T2. (6) The first vacuum valve V1 is closed and the load current is reduced to T2.
Move to the circuit of -M1-V1. (7) The second vacuum valve V2 opens.

At the time of switching from tap T2 to T1 As shown in (8) to (13), the switching of the second movable contact (M2) precedes the switching of the first movable contact (M2) as in the case of switching from tap T1 to T2. The switching of the movable contact (M1) follows this.
In addition, there is no particular change in the interlocking of the driving mechanism, the switching sequence, and the like as compared with the switching from the tap T1 to the tap T2.

Next, the details of the one-tap switching operation will be described with reference to FIGS. FIGS. 4 to 6 show a situation where the movable contact of the tap selector is switched by the energy storage mechanism via the Geneva gear. Hereinafter, the switching operation will be described step by step.

FIGS. 4A and 4B show the initial state. In this state, the tension spring 7 is not charged. 4 (c) and 4 (d) show states of the start of the energy storage operation and the start of the resistance contact switching operation.

By the rotation of the gear 3, the pins 6 and 9 rotate simultaneously, the pin 9 rotates the arm 4, the tension spring 7 starts to accumulate, and the pin 6 starts to mesh with the Geneva gear 10, The second movable contact 44 (M2) of the tap selector is separated from the fixed contact (tap T8).

FIGS. 5A and 5B show a state in which the resistance contact switching operation is started during the charging operation. At the same time as the gear 3 continues to rotate, the pin 9 further rotates the arm 4 to advance the energy storing operation. Further, when the pin 6 further rotates and separates from the engagement with the Geneva gear 10, the second movable contact 44 (M2) is completely closed to the fixed contact 46 (tap TO), and the resistance contact is switched. To end.

FIGS. 5 (c) and 5 (d) show the state of the end of the accumulating operation. The pin 9 further rotates the arm 4 at the same time as the gear 3 continues to rotate, and when the rotation angle from the initial state becomes 180 °, the amount of energy stored in the tension spring 7 becomes maximum, and the energy is stored. To end.

FIGS. 6A and 6B show the start of the snap operation.
This shows the main contact switching operation start state. After the end of the accumulating operation, when the extension spring 7 is released, the arm 4 separates from the pin 9 and starts rotating rapidly by the extension force of the extension spring 7. The rotation of the arm 4 causes the segment 20 to rotate the pin 21, thereby causing the pin 23 to mesh with the Geneva gear 25 via the driver 22, and the first movable contact 45 (M 1)
Is separated from the fixed contact 46 (tap T8).

FIGS. 6C and 6D show the end of the snap operation.
This shows the end state of the main contact switching operation. When the arm 4 is further rotated by the tension of the tension spring 7 and the pin 23 is released from the engagement with the first Geneva gear 25, the first movable contact 45 (M1) is completely connected to the fixed contact 46. Is turned on and the switching operation of the main contact is completed.

FIGS. 7 to 9 show the switching operation in the reverse direction to the switching operation in the forward direction in FIGS. 4 to 6, but the switching of the second movable contact (M2) is performed in the same manner as in FIGS. The switching is preceded, and the switching of the first movable contact (M1) is not particularly different from the forward switching, such as a switching sequence other than following the switching, the interlocking of the driving mechanism, and the like. Omitted.

Next, in the process of the one-tap switching operation, the process from the end of the charging operation to the end of the main contact switching operation will be described in detail with reference to FIGS. 10 to 15A
Indicates a circuit in a switching operation process.

FIGS. 10 to 15B show the operation of opening and closing the vacuum valve by the cam. Cam groove 3 of groove cam 30
5 and 36 are configured as shown in the figure. When the rollers 37 and 38 connected to the vacuum valve are displaced upwardly of the cam grooves 35 and 36, the vacuum valve is opened, and when the rollers 37 and 38 are displaced downwardly, the vacuum valve is opened. Acts to close the valve.

FIGS. 10 (c) through 15 (c) show the first movable contact 45 (M
1) shows a state where switching is performed. The operation of the tension spring 7 rotates the segment 20 via the arm 4. The rotation of the segment 20 causes the pin 21 to rotate, and the pin 23 simultaneously rotates via the driver 22. When the pin 23 meshes with the first Geneva gear 25, the insulating shaft 26 is rotated, and the first movable contact 45 of the tap selector is rotated.
(M1) is switched from tap T8 to tap T0.

Here, FIGS. 10 to 15 will be described step by step. FIGS. 10A to 10C show a state where the accumulating operation of the extension spring 7 is completed, and the tap T8 of the tap winding is connected to the first movable contact 45 (M1) of the tap selector.
Indicates a selected state.

The first vacuum valve 31 (V1) is closed, and the transformer load current flows through the tap T8, the first movable contact 45 (M1), and the first vacuum valve 31 (V1) as indicated by the bold line in the figure. Have been.

The roller 38 is located below the cam groove 36, and closes the first vacuum valve 31 (V1). On the other hand, the roller 37 is located at a position above the cam groove 35 and opens the second vacuum valve 32 (V2).

FIGS. 11A to 11C show a state in which the second vacuum valve 32 (V2) is closed. By the operation of the tension spring 7, the arm 4, the segment 20, the pin 21
The groove cam 30 starts rotating by driving the insulating drive shaft 24 directly connected to the driver, and the roller 37 moves downward from the upward displacement of the cam groove 35 as shown in the figure. And the second vacuum valve 32 (V2) is closed. With the closing of the second vacuum valve 32, a short circuit is formed between the taps T8 and T0, and the circulating current suppressed by the current limiting resistance flows.
The transformer load current continues to flow through the T8-M1-V1 side circuit.

FIGS. 12A to 12C show that the first vacuum valve 31 (V1) is opened to cut off the transformer load current, and at the same time, the load current changes from the circuit on the tap T8 side to the circuit on the tap T0 side. The state which has moved is shown.

When the groove cam 30 continues to rotate through the driver 22 by the operation of the tension spring 7, the roller 38 moves from the downward displacement of the cam groove 36 to the upward displacement, and the first vacuum valve 31 (V1). At the same time, the transformer load current and the circulating current are cut off, and the circuit is moved to the T0-M2-R-V2 side circuit. Further, the tension force of the tension spring is applied to the pin 23 of the driver 22 via the arm 4, the segment 20, and the pin 21.
To start driving the Geneva gear 25. Due to the driving of the Geneva gear 25, the first movable contact 45 (M1) of the tap selector starts to be separated from the tap T8 via the insulating shaft 26.

FIGS. 13A to 13C show that the first movable contact 45 (M1) of the tap selector is separated from the tap T8,
A state has been reached in which an intermediate position between the tap T8 and the tap T0 has been reached.

The first movable contact 45 (M
1) is separated from tap T8, and taps T8 and T0
And a state in which the intermediate position has been reached. The operation of the tension spring 7 causes the driver 22 to continue rotating, and at the same time, rotates the pin 23 so that the first fixed contact 45
(M1) is tapped via the first intermittent gear mechanism 100.
8 and an intermediate position between the tap T0. During this time, since the rollers 37 and 38 are moving in the horizontal positions of the cam grooves 35 and 36, the first vacuum valve 31 (V1) and the second vacuum valve 32 (V2) are kept open and closed. Therefore, the transformer load current continues to flow through the circuit on the T0-M2-R-V2 side.

FIGS. 14A to 14C show that the first movable contact 45 (M1) of the tap selector reaches T0, then the first vacuum valve 31 (V1) is closed, and the transformer is turned off. This shows a state in which the load current has moved to the circuit on the first vacuum valve V1 side.

The operation of the tension spring 7 causes the driver 22 to continue rotating and drive the first intermittent gear mechanism 100 to further rotate the first movable contact 45 (M1) of the tap selector to the tap T0. Let it reach. At this time, since the first vacuum valve 31 (V1) is open, it is turned on in a no-load, no-voltage state and does not involve firing. When the groove cam 30 continues to rotate via the driver 22, the rollers 3
8 moves from the upper displacement of the cam groove 36 to the lower displacement,
At the same time as closing the vacuum valve 31 (V1), and simultaneously loading the transformer load current from the circuit T0-M2-R-V2 to T0-M.
1-V1 is moved to the circuit.

FIGS. 15A to 15C show a state in which the second vacuum valve 32 (V2) is open. When the groove cam 30 continues to rotate by the operation of the tension spring 7,
The roller 37 moves from the downward displacement to the upward displacement of the cam groove 35 to open the second vacuum valve 32 (V2). During this time, the load current continues to flow through the circuit on the T0-M1-V1 side.

As described above, in the present embodiment, of the two movable contacts, only the current-limiting resistor R and the second movable contact M2 connected in series to the second vacuum valve V2 precede the quick disconnection operation. After the switching is completed, the other first movable contact M1 and the two vacuum valves V1 and V2 are configured to be quickly turned off in a predetermined order, so that the tap selector moves between the fixed contacts. The number of contacts to be opened and closed becomes three, so that the number of contacts can be reduced as compared with the related art. Therefore, the fixed contact portion can be made smaller in the radial direction as compared with the conventional case, and the whole can be made compact, low-cost and more practical.

Further, since the movable contact is driven by the Geneva driver and the Geneva gear, the rotation angle when the movable contact moves between the fixed contacts can be accurately defined. Further, first and second insulated driving shafts are provided on the driven side of the first and second Geneva gears, and first and second movable contacts are attached and fixed to the insulated driving shafts, respectively, so that the Geneva gear can be rotated. Accordingly, the fixed contacts can be sequentially selected, the first insulating drive shaft is tubular, the second insulating drive shaft is a solid shaft, and both are arranged coaxially and the first drive shaft is An opening through which the second movable contact can protrude is provided. This opening is sized so that the second movable contact can rotate in the forward and reverse directions in both the forward and reverse directions with respect to the first movable contact. The order of preceding can be satisfied.

A groove cam is directly connected to a driven portion of the first intermittent gear mechanism. The groove cam is provided with two grooves for opening and closing the first and second vacuum valves. Since the predetermined operation is performed in accordance with the contact and the tap switching order, the timing of the quick-start operation sequence can be accurately set.

[0060]

As described above, according to the present invention, when the fixed contacts connected to the tap windings are arranged at regular intervals along the circumference, the radial direction thereof can be reduced, and the overall Can be provided compactly.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a specific configuration of an embodiment of a load tap changer according to the present invention.

FIG. 2 is a circuit diagram showing a switching operation process in the embodiment.

FIG. 3 is a diagram showing a switching sequence in the embodiment.

FIG. 4 shows a state in which the resistance movable contact and the main movable contact of the tap selector are switched in the forward direction by the energy storage mechanism via the second intermittent gear mechanism and the first intermittent gear mechanism in the embodiment. FIG. 4 is an explanatory diagram showing a state in which an energy storage operation starts and a resistance contact switching operation starts from the initial state of FIG.

FIG. 5 is an explanatory diagram showing a state in which the resistance contact switching operation is started to an end of the charging operation during the energy storing operation.

FIG. 6 is an explanatory diagram showing a snap operation start, a main contact switching operation start state, a snap operation end, and a main contact switching operation end state.

FIG. 7 shows a state in which the resistance movable contact and the main movable contact of the tap selector are switched in the reverse direction by the energy storage mechanism via the second intermittent gear mechanism and the first intermittent gear mechanism in the embodiment. FIG. 4 is an explanatory diagram showing a state in which an energy storage operation starts and a resistance contact switching operation starts from the initial state of FIG.

FIG. 8 is an explanatory diagram showing a state in which the resistance contact switching operation is started to an end of the charging operation during the energy storing operation.

FIG. 9 is an explanatory diagram showing a snap operation start, a main contact switching operation start state to a snap operation end, and a main contact switching operation end state.

FIG. 10 is a diagram showing a state in which the accumulating operation of the extension spring is completed and a state in which the first movable contact of the tap selector selects the tap of the tap winding in the embodiment.

FIG. 11 is a view showing a state in which the second vacuum valve is closed.

FIG. 12 is a diagram showing a state in which the first vacuum valve is opened, the transformer load current is cut off, and at the same time the load current moves from the tap side circuit to the tap side circuit.

FIG. 13 is a diagram showing a state in which the first movable contact of the tap selector is separated from the tap T8 and reaches an intermediate position between the tap T8 and the tap T0.

FIG. 14 shows a state in which the first movable contact of the tap selector reaches the tap T0, the first vacuum valve is closed, and the transformer load current moves to the circuit on the first vacuum valve side. FIG.

FIG. 15 is a diagram showing a state in which the second vacuum valve is opened.

FIG. 16 is an explanatory diagram of a configuration of a conventional on-load tap changer and a tap change operation process.

FIG. 17 is an explanatory diagram of the tap switching operation process following FIG. 16;

FIG. 18 is a circuit diagram illustrating the configuration of another conventional tap changer under load.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Electric motor 2 ... Pinion 3 ... Gear 4 ... Arm 5 ... Shaft 6,9 ... Pin 7 ... Tension spring 8 ... Support point pin 10,25 ... Geneva gear 11,24 ... Insulated drive shaft 20 Segment 22 Driver 26 Insulated shaft 30 Groove cam 31, 32 Vacuum valve 33, 34 Drive lever 35, 36 Cam groove 40, 41 Current collector ring 42, 43 ... Arms 44, 45 ... Movable contacts 46 ... Fixed contacts

Claims (4)

[Claims] 1. A plurality of fixed contacts connected to taps of a transformer tap winding, a first load current energizing movable contact that contacts the fixed contacts, and a contact between the fixed contacts and a short circuit between the taps. And a second movable contact for supplying a circulating current to the first movable contact. The first movable contact has a first vacuum valve, and the second movable contact has a current limiting resistor for suppressing a circulating current and a second current limiting resistor. And the first and second movable contacts contact the same fixed contact to form a parallel circuit,
When the tap is switched, the second movable contact connected to the current limiting resistor for suppressing the circulating current is always switched prior to the first energizing movable contact in the same forward direction switching and also in the reverse direction switching. And a load tap changer configured to come into contact with a fixed contact connected to an adjacent tap, comprising: a driving-side drive unit; Energy accumulating device for accumulating static energy for performing the operation, and the second movable contact during operation until a predetermined static energy is accumulated in the energy accumulating device while being driven by being connected to the driving side drive unit. A second intermittent gear mechanism for moving the first movable contact to an adjacent fixed contact, and an operation for quickly cutting the first movable contact by releasing static energy stored in the energy storage device connected to the driven side of the energy storage device. First intermittent gear machine And a cam mechanism connected to the driven side of the energy storage device and opening and closing the first and second vacuum valves in a predetermined order by releasing the static energy. Tap changer. 2. A first driving device for driving first and second movable contacts.
2. The on-load tap changer according to claim 1, wherein the second intermittent gear mechanism comprises a pair of Geneva mechanisms provided with one Geneva driver and a Geneva gear having a plurality of teeth. 3. A first and second insulated driving shaft is provided on a driven side of the first and second Geneva gears, and the first and second movable contacts are mounted and fixed to the insulated driving shaft, respectively. A fixed contact can be sequentially selected in accordance with the rotation, and the first insulating drive shaft is coaxially arranged as a tubular, the second insulated drive shaft as a solid axis, and the first insulated drive shaft is connected to the first insulated drive shaft. Is provided with an opening through which the second movable contact can protrude, and the opening is sized so that the second movable contact can rotate ahead of the first movable contact in both forward and reverse directions. The tap changer under load according to claim 2. 4. A grooved cam is directly connected to a driven portion of the first Geneva driver to open and close the first and second vacuum valves with the grooved cam, and a predetermined movable contact and a predetermined switching order according to a tap switching order. 3. The on-load tap changer according to claim 2, wherein two grooves are provided for performing the operation.