JPH0544809B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention particularly relates to an on-load tap changer with an improved quick-off operation mechanism for opening and closing a plurality of vacuum switches.

[Background of the invention]

In recent years, since a fire in a high-rise building can cause a major disaster, power substation equipment has come to be required to be disaster-proof. Transformers are no exception, with the shift from oil-filled transformers to SF _6- filled or insulating gas type transformers. On-load tap changers used in insulating gas type transformers produce a large amount of fine particles when the tap selector switches from one tap terminal to the other and interrupts the current with a contact exposed in the gas. Metal powder comes out.
Since metal powder impairs the insulation in gas insulated transformers, vacuum switches have been used to replace contacts in the gas.

As shown in Fig. 1, the equivalent circuit of an on-load tap changer using a vacuum switch includes a plurality of tap terminals T ₁ , T ₂ , pulled out from both sides of the tap winding T.
Tap selectors S ₁ and S ₂ move between T ₃ and T ₄ . now,
A case will be described in which the tap selector _S2 is switched from one tap terminal _T2 to the other tap terminal _T4 .

(1) When the first vacuum switch VS ₁ is opened and the fourth vacuum switch VR ₂ is closed, the current flows to the tap terminal T ₃ -
One tap selector S ₁ - current limiting resistor r ₁ - third vacuum switch VR ₁ - neutral terminal N, tap terminal T ₄
- the other tap selector S ₂ - current limiting resistor r ₂ - the fourth
Vacuum switch VR ₂ - flows to neutral terminal N. In other words, a circulating current flows.

(2) In this state, if the second vacuum switch VR ₁ is opened and the third vacuum switch VS ₂ is closed, the circulating current will stop flowing and the current will flow through T ₄ -VS ₂ -VR ₂ -N.

The above explained the effect of increasing the voltage when the on-load tap changer is connected to the primary side of the transformer. However, when decreasing the voltage, after opening the third vacuum switch VS ₂ , After closing the switch VR ₁ , further open the fourth vacuum switch VR ₂ ,
Close the first vacuum switch VS ₁ and perform the same operation as described above. The operating time difference of each vacuum switch is
Perform according to the sequence shown in the figure. These vacuum switches are opened and closed by the quick-cut operation mechanism section 1.

However, in the conventional quick-cut operation mechanism, in order to obtain quick open-close operation according to the appropriate sequence of each vacuum switch, the circulating current flows for a long time, and the current limiting resistors r ₁ and r ₂ There was a lot of heat and there was a risk of melting. It also requires a large driving force,
It was impossible to avoid increasing the size of the drive mechanism.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a compact on-load tap changer that can quickly and reliably open and close each vacuum switch.

[Summary of the invention]

The on-load tap changer of the present invention which achieves this object has a plurality of tap terminals drawn out from both sides of the tap winding, and a tap selection provided on both sides of the tap winding, which moves between the tap terminals. and two vacuum switches inserted in series between each of the tap selectors and the neutral terminal;
The on-load tap changer has a current limiting resistor connected in parallel to each of the vacuum switches on the tap terminal side, and a quick-off operation mechanism that opens and closes each of the vacuum switches at a predetermined time difference, The cutting operation mechanism includes a rotatable drive shaft and two quick cutting guides that are mounted on the drive shaft at a predetermined distance and driven, each of the quick cutting guides having a predetermined shape. A pair of guide parts are formed at intervals (grooves), each guide part has a protrusion part and a groove part, and the protrusion part is located on the side (inner side) of the other quick cutting guide. It consists of a second protrusion and a first protrusion located on the opposite side (outside) of the quick cutting guide at a distance from the second protrusion and provided on both sides with the groove in between, and the groove and further arranged so that the guide portion of the one quick cutting guide is located at a position corresponding to the groove of the other quick cutting guide when viewed from the axial direction.
two quick-cut guides, which are mounted on a support shaft parallel to the drive shaft so as to be movable in the axial direction, are provided correspondingly to the two quick-cut guides, and engage with the inner side of the second protrusion, respectively. an inner cam floor, and is mounted on the support shaft so as to be axially movable and spaced apart from the outer side of the inner cam floor, and engages with the outer side of the first protrusion, respectively;
provided between two interconnected outer cam floors and the inner cam floor, the inner cam floor engaging inside the second protrusion of one of the quick cutting guides, and the outer cam floor engaging the first one of the same quick cutting guide; Energy is accumulated by engaging the outer side of the protrusion, and when the engaged outer cam floor disengages from the first protrusion and moves into the groove, the accumulated energy is released and causes the outer cam floor to move axially. It is characterized by comprising a moving spring and a time difference mechanism that is driven by the movement of the outer cam floor and opens and closes each of the vacuum switches at a predetermined time difference.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to FIGS. 3 to 6.

Quick cutting operation mechanism part 1 shown in FIGS. 3 and 4
is structured as follows. The insulating support part 2 is composed of three insulating support pieces 2A, 2B, and 2C, and an upper metal fitting 4A and a lower metal fitting 4B are attached to the upper and lower ends of the insulating support part 2 with bolts 3. The drive shaft 5 is supported by bearings 4C provided on both metal fittings 4A and 4B, and is rotated clockwise A or counterclockwise B by a drive unit (not shown), such as a motor. The cam drive part 6 shown in FIG. It is fixed at The cam drive section 6 consists of a major arc section 6A and a small semicircular arc section 6B, and a surface 6C is formed between both semicircular sections, and upper and lower quick cutting guide sections 8 and 9 are fitted on the outer circumferential side of the cam drive section 6. It is crowded. The gap 7 is between the cam drive unit 6 and the quick cutting guides 8 and 9.
For the time being, it is formed between 6C.

The wing-shaped quick cutting guides 8 and 9 have a pair of wing-shaped guide parts 10, 12, 11, 13 and a groove part 11.
3 and 14. The combined arrangement of the upper and lower quick cutting guides 8 and 9 is as shown in FIGS.
, the lower guides 12 and 1 correspond to the upper groove 113.
3 is placed. In other words, both guides and both grooves do not correspond to each other. a pair of upper guides 10,
The upper and lower ends of the drive shaft 11 are constituted by a first protrusion 15A and a second protrusion 15B extending in a direction opposite to the drive shaft 6, and a groove 15C. 1st and 2nd
Slanted surfaces 15D are provided at both ends of the protrusions 15A and 15B.
is formed. The structure of the lower guides 12 and 13 is exactly the same as described above, including a first protrusion 16A, a second protrusion 16B, a groove 16C, and an inclined surface 16D.
It is formed from. The inclined surfaces 15D and 16D extend from the first protrusion parts 15A and 16A to the second protrusion part 15.
As it approaches B, 16B, the second protrusion 15
The longitudinal dimensions of B and 16B are formed to become smaller in sequence. The inclined surfaces 15D and 16D of the upper quick cutting guide 8 and the lower quick cutting guide 9 are arranged in correspondence with each other. First protrusion 15 of both quick cutting guides
Inner and outer cam floors 17A, 18A, 17 between A, 16A and second projections 15B, 16B
B and 18B are in contact and separation.

The two support shafts 19 are supported between both support metal fittings 4A and 4B, and are supported between the inner cam floor support metal fittings 20A and 20.
B and outer cam floor support fittings 21A, 21B
is inserted so that it can be raised and lowered. Second protrusions 15B, 16 of inner cam floor support fittings 20A, 20B
The inner cam floors 17A and 17B are rotatably attached to the surface corresponding to B by pins 22. The spring 23 is inserted into the support shaft 19 between the inner cam floors 17A and 17B. The outer cam floors 18A, 18B are rotatably attached to the surfaces of the outer cam floor support fittings 21A, 21B corresponding to the first protrusions 15A, 16A by means of a pin 22. Both outer cam floor support fittings 21A, 21B are integrally connected, and a connecting portion 24 protrudes in the outer circumferential direction.
is installed. The communication section 24 has a ring shape and is connected to the rods of the U-phase, V-phase, and W-phase vacuum switches to communicate with the time difference mechanism section 25.

The time difference mechanism section 25 is supported by the communication section 24, and is attached to A or B of the outer cam floor support fittings 21A, 21B.
It moves by sliding in the direction. Time difference mechanism section 25
Two rods 27A and 27B are attached to both ends of the rod. In Fig. 3, the two rods 27A, 27B extend through the support fittings 4A, 4B, but in reality, the other two rods correspond to the two rods 27A, 27B mentioned above. It extends as shown in Figure 4B. These rods are designated as 28A and 28B. 1st vacuum switch VS ₁ and 4th vacuum switch VR ₂
are attached to rods 27A and 27B, and the second vacuum switch VR ₁ and third vacuum switch VS ₂ are attached to rod 28.
Supported by A and 28B. The fixed side rods of the first vacuum switch VS ₁ and the second vacuum switch VR ₁ are assumed to be 27C and 28C. The V phase, U phase, and W phase of these vacuum switches are arranged along the circumferential direction.

Next, the operation of the quick cutting operation mechanism section 1 will be explained.

(1) When closing the fourth vacuum switch VR ₂ after opening the first vacuum switch VS ₁ The lower second protrusion 16B in FIG. 6A corresponds to the upper groove 113, and the outer cam floor 18A and the inner Cam floor 17A, 17B
The spring 23 is placed thereon, and the outer cam floor 18B is in contact with the other surface corresponding to the groove 16C. In this state, if the drive shaft 5 is rotated in the clockwise direction A by driving a drive source (not shown),
The upper quick cutting guide 8 and the lower quick cutting guide 9 are also rotated in the same direction and moved to the position shown in FIG.

In this position, the outer cam floors 18A and 18B contact the first protrusions 15A and 16A', and the inclined surface 15D presses the upper inner cam floor 17A toward the lower inner cam floor, so that the spring 23 is compressed and energized. Accumulate. In this state, both guides 10 to 13 continue to rotate in the clockwise direction A and come to the position C in the figure.

In this position, the lower guide 12 has moved away from the outer cam floor 18B, and the lower groove 14 has moved to a position corresponding to the outer cam floor 18B, but the upper outer cam floor 18A is in contact with the end of the first protrusion 15A, and the inner cam floor 1
Since the spring 7A is pressed by the second protrusion 15B, the spring 23 is compressed to the maximum. Therefore, the energy storage capacity of the spring 23 is maximum. In this state, both guides 10 to 1
3 rotates and comes to the positions D and E in the same figure.

At this position, the outer cam floor 18A moves into the groove 15C, releasing the stored energy of the spring 23. The release energy at this time moves one inner cam floor 17A to the second protrusion 15.
B, moves the other inner cam floor 17B downward, and presses the outer cam floor 18B.

As a result, the time difference mechanism section 25 moves in the A direction, opens the first vacuum switch VS ₁ (third vacuum switch VR ₁ ), and then closes the fourth vacuum switch VR ₂ (second vacuum switch VS ₂ ). The time difference shown in FIG. 2 for each vacuum switch is determined by the time difference mechanism section 25.
Do it with The time difference mechanism section 25 has rods 27A, 2
This is done by changing the length of the 7B, etc., or the moving distance, such as by changing the gap.

Also, after opening the second vacuum switch VS ₂ (fourth vacuum switch VR ₂ ), the first vacuum switch VS ₁ is opened.
To close the third vacuum switch VR ₁ , rotate the drive shaft 5 in the counterclockwise direction B and follow the steps from A to D in Figure 7. You can reverse it.

In this quick cutting operation mechanism 1, the outer cam floor 1
8A contacts the first protrusion 15A of the quick cutting guide 8, and the second protrusion 15B contacts the inner cam floor 17A.
When the outer cam floor 18A moves to the groove part 15C with the compressive force of the spring 23 maximized by pressing the The U-phase, V-phase, and W-phase vacuum switches (VS ₁ , VS ₂ , VR ₁ , VR ₂ ) can be opened and closed. Therefore, since the opening and closing speed of each vacuum switch can be increased, the time during which the circulating current flows in the load tap changer can be shortened. As a result, the heat generated by the current limiting resistors r ₁ and r ₂ can be reduced, so the on-load tap changer can be made smaller. Also, if the quick cutting guides 8 and 9 rotate, the outer cam floor 1
8A and 18B reliably move to the grooves 15C and 16C, so that each vacuum switch can be reliably opened and closed.

Furthermore, in this embodiment, since the gap 7 is provided,
Each vacuum switch can be opened and closed quickly. That is, in FIGS. 5B and 6C, the outer cam floor 18
When A is in contact with the joint R of the first protrusion 15A, a spring force P ₁ and a component force P ₂ act on the outer cam floor 18A, and this combined force P ₃ acts in the same direction as the clockwise direction A. Therefore, the quick cutting guide 8 moves in the same direction by a gap of 7 minutes. As a result, the outer cam floor 18
A will surely fall into the groove 15C, and the falling time can be shortened. Therefore, since the opening/closing time of each vacuum switch can be shortened, the on-load tap changer can be further downsized.

〔Effect of the invention〕

As described above, according to the on-load tap changer of the present invention, it is possible to reduce the size.

[Brief explanation of the drawing]

FIG. 1 is an equivalent circuit of a conventional on-load tap changer, FIG. 2 is a sequence characteristic diagram of FIG. 4A is a sectional view taken along the line A-A in FIG. 3, FIG. 4B is a partial schematic explanatory diagram of FIG.
E and FIGS. 7A to 7D are explanatory diagrams of the operation of the quick cutting operation mechanism section. T...Tap winding, _T1 to _T4 ...Tap terminal,
S ₁ , S ₂ ...Tap selector, VS ₁ , VS ₂ , VR ₁ ,
VR ₂ ...Vacuum switch, 1...Quick cut operation mechanism section,
5... Drive shaft, 8, 9... Quick cutting guide, 10, 1
1, 12, 113...Guide, 13, 14...Groove, 15A, 15B, 16A, 16B...Protrusion, 15C, 16C...Groove, 17, 18...Cam floor, 23...Spring, 24... Liaison Department, 25
...Time difference mechanism section.

Claims (1)

[Scope of Claims] 1. A plurality of tap terminals drawn out from both sides of the tap winding, tap selectors provided on both sides of the tap winding and movable between the tap terminals, and each of the tap selectors. and a neutral terminal, two vacuum switches are inserted in series, and a current limiting resistor is connected in parallel to each vacuum switch on the tap terminal side, and each vacuum switch is opened and closed at a predetermined time difference. The on-load tap changer has a quick-cut operation mechanism section, the quick-cut operation mechanism section is equipped with a rotatable drive shaft, and a drive shaft mounted on the drive shaft at a predetermined distance from each other. A pair of guide parts are formed at a predetermined interval (groove) in each of the quick cut guides, and each guide part has a protrusion part and a groove part. The protruding portion is located on the opposite quick cutting guide side (outside) with a space between a second protruding portion located on the other quick cutting guide side (inside) and the second protruding portion is located on the opposite quick cutting guide side (outside) and sandwiching the groove portion. and a first protrusion provided on both sides, the groove being formed at a position corresponding to the second protrusion, and further comprising:
two quick-cutting guides arranged such that the guide portion of the one quick-cutting guide is located at a position corresponding to the groove of the other quick-cutting guide when viewed from the axial direction; two inner cam floors mounted so as to be movable in the axial direction, provided correspondingly to the two quick cutting guides, and engaging with the inner side of the second protrusion, respectively; two outer cam floors installed at intervals on the outside of the inner cam floor, respectively engaged with the outer side of the first protrusion, and connected to each other; Energy is accumulated by engaging the inner side of the second protrusion of the quick cut guide and the outer cam floor engaging the outer side of the first protrusion of the same quick cut guide, and the engaged outer cam floor a spring that moves the outer cam floor in the axial direction by releasing the accumulated energy when it comes off the protrusion and moves into the groove; and a spring that is driven by the movement of the outer cam floor and opens and closes each vacuum switch at a predetermined time difference. 1. A load tap changer comprising a time difference mechanism section. 2. In claim 1, the quick cutting guide is mounted around a cam drive section provided on the drive shaft, and the cam drive section includes a major arc section, a small arc section, and both semicircular arc sections. A space is provided between the corresponding surface and the surface of the quick cutting guide.
An on-load tap changer characterized by forming: