On-load tap changer and on-load tap changer transformer

Abstract

The present invention provides an on-load tap changer that can drive a tap selector and a changeover switch with a simple configuration that reduces the number of parts. [Solution] An on-load tap changer comprising a tap selector and a changeover switch, comprising: a drive shaft for driving the tap selector; an energy storage member for storing the rotational force of the drive shaft as a biasing force; an energy storage case that can move forward and backward by the biasing force released by the energy storage member; a cam that rotates in conjunction with the forward and backward movement of the energy storage case; and a cam follower that moves in accordance with the rotation of the cam and drives the changeover switch.

Description

Technical Field

[0001] The present disclosure relates to a load tap changer and a load tap changing transformer.

Background Art

[0002] As a device for keeping the distribution voltage within an appropriate range, a load tap changing transformer (LRT) is used. The load tap changing transformer includes a transformer and a load tap changer. The load tap changer includes a tap winding connected to the main winding of the transformer, a tap selector that adjusts the transformation ratio by selecting a tap of the tap winding, and a switching switch that controls the current path during tap switching.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a conventional load tap changer, the drive system for driving the switching switch and the drive system for driving the tap selector have separate configurations, and two drive systems are required. For example, the load tap changer had a complicated configuration such as including a coaxial hollow shaft and solid shaft.

[0005] An object of the present disclosure is to provide a load tap changer and a load tap changing transformer that can drive a tap selector and a switching switch with a simple configuration with a reduced number of parts.

Means for Solving the Problems

[0006] The on-load tap changer of this disclosure is an on-load tap changer comprising a tap selector and a changeover switch, the drive shaft for driving the tap selector, an energy storage member for storing the rotational force of the drive shaft as a biasing force, an energy storage case that can move forward and backward by the biasing force released by the energy storage member, a cam that rotates in conjunction with the forward and backward movement of the energy storage case, and a cam follower that is driven by the rotation of the cam and drives the changeover switch.

[0007] The on-load tap-changing transformer of this disclosure comprises a transformer and the on-load tap-changing device, wherein the on-load tap-changing device switches the transformation ratio of the transformer. [Effects of the Invention]

[0008] According to this disclosure, it is possible to provide an on-load tap changer and an on-load tap changer transformer that can drive a tap selector and a changeover switch with a simple configuration that reduces the number of parts. [Brief explanation of the drawing]

[0009] [Figure 1] This is a circuit diagram showing a load-tap changing transformer according to this embodiment. [Figure 2] This is a cross-sectional view of the energy storage device. [Figure 3] This is a side view of the energy storage device. [Figure 4] This is a cross-sectional view along line IV-IV in Figure 2. [Figure 5] This is a schematic diagram showing the state where the biasing force is released and the energy storage case moves to the left. [Figure 6] This is a schematic diagram showing the state where the movable case has moved to the right and accumulated energy. [Figure 7] This is a schematic diagram showing the state where the biasing force is released and the energy storage case moves to the right. [Modes for carrying out the invention]

[0010] On-load tap changers and on-load tap changer transformers according to embodiments of this disclosure will be described below with reference to the drawings. This disclosure is not limited to these examples, but is indicated by the claims, and all modifications within the meaning and scope of equivalence to the claims are intended. Furthermore, at least some of the embodiments described below may be arbitrarily combined.

[0011] Figure 1 is a circuit diagram showing an on-load tap-changing transformer according to this embodiment. The on-load tap-changing transformer comprises a transformer TR having a main winding (primary winding) W and an auxiliary winding (secondary winding), and an on-load tap changer 1. The on-load tap changer 1 switches the transformation ratio of the transformer TR, thereby adjusting the distribution voltage to an appropriate range.

[0012] The under-load tap changer 1 comprises a motor 10 (see Figure 2), a tap selector 11, a changeover switch 12, and an energy storage device 13.

[0013] The tap selector 11 is equipped with a tap winding Wt. The tap winding Wt is connected to the main winding W of the transformer TR and has taps 11a drawn out from multiple locations along the winding. The taps 11a include multiple odd-numbered taps t1, t3, ... and multiple even-numbered taps t2, t4, ...

[0014] The tap selector 11 comprises an odd tap selector T1 and an even tap selector T2. The odd tap selector T1 is connected to one of the odd taps t1, t3, ... selected according to the load on the secondary side of the transformer TR (in Figure 1, this is the odd tap t1). The even tap selector T2 is connected to one of the even taps t2, t4, ... selected according to the load on the secondary side of the transformer TR (in Figure 1, this is the even tap t2).

[0015] The changeover switch 12 is a switch that controls the current path when tap switching, and comprises a current-limiting resistor R, vacuum valves M1 and M2, and switch 2. The current-limiting resistor R and vacuum valve M1 are connected in series to the odd-number tap selector T1 and the neutral wire N. Specifically, one end of the current-limiting resistor R is connected to the odd-number tap selector T1, and the other end of the current-limiting resistor R is connected to one end of the vacuum valve M1. The other end of the vacuum valve M1 is connected to the neutral wire N.

[0016] Switch 2 comprises fixed contacts 21 and 22 and a movable contact 23. Fixed contact 21 is connected to an odd-numbered tap selector T1. Fixed contact 22 is connected to an even-numbered tap selector T2. The common terminal of movable contact 23 is connected in series with the neutral wire N via a vacuum valve M2, and movable contact 23 selectively connects to either fixed contact 21 or 22. In Figure 1, movable contact 23 is connected to fixed contact 21.

[0017] Vacuum valves M1 and M2 are openable and closable vacuum shutoff switches. Specifically, vacuum valves M1 and M2 comprise a vacuum cylinder made of insulating material, a fixed electrode and a movable electrode that can be separated inside the vacuum cylinder, a bellows, and flanges that seal both ends of the vacuum cylinder. The fixed electrode is supported by a flange provided on one end of the vacuum cylinder. The movable electrode is supported by a flange provided on the other end of the vacuum cylinder so that it can move back and forth in the direction of the centerline of the vacuum cylinder. The movable electrode side is kept vacuum airtight by the bellows. When vacuum valve M1 is closed, the current limiting resistor R is connected to the neutral wire N, and when vacuum valve M1 is open, the current limiting resistor R is disconnected from the neutral wire N. When vacuum valve M2 is closed, the common terminal of the movable contact 23 is connected to the neutral wire N, and when vacuum valve M2 is open, the common terminal is disconnected from the neutral wire N.

[0018] When one tap 11a is selected by the tap selector 11 and the selected tap 11a is electrically connected by the changeover switch 12, the turns ratio of the transformer TR is switched. That is, by tap switching, the voltage output from the secondary side of the transformer TR can be adjusted. The opening / closing switching of each of the vacuum valves M1 and M2 and the switching of the connection destination of the movable contact 23 are performed by the energy storage device 13 as will be described later.

[0019] When the movable contact 23 is connected to the fixed contact 21, both of the vacuum valves M1 and M2 are closed. As a result, the circuit between the odd tap selector T1 and the neutral line N is energized. In the middle of this circuit, there are a first circuit 121 passing through the current-limiting resistor R and the vacuum valve M1, and a second circuit 122 passing through the switch 2 and the vacuum valve M2. The first circuit 121 and the second circuit 122 are parallel to each other. Due to the resistance of the current-limiting resistor R, the load current flowing between the odd tap selector T1 and the neutral line N mainly passes through the second circuit 122. On the other hand, the circuit between the even tap selector T2 and the neutral line N is blocked by the switch 2.

[0020] When the connection destination of the movable contact 23 is switched from the fixed contact 21 to the fixed contact 22, first, the vacuum valve M2 is opened. Since the second circuit 122 is blocked by the vacuum valve M2, the load current flows between the odd tap selector T1 and the neutral line N through the first circuit 121.

[0021] Next, the movable contact 23 is connected to the fixed contact 22. As a result, the second circuit 122 is blocked by the switch 2 and the vacuum valve M2, and the circuit between the even tap selector T2 and the neutral line N is blocked by the vacuum valve M2. Since no load current flows between the even tap selector T2 and the neutral line N, it is possible to prevent an arc from occurring when the movable contact 23 is connected to the fixed contact 22. On the other hand, the load current continues to flow between the odd tap selector T1 and the neutral line N through the first circuit 121.

[0022] Next, the vacuum valve M2 is closed. As a result, load current flows between the even-tap selector T2 and the neutral wire N. Also, the odd-tap selector T1 and the even-tap selector T2 are short-circuited via the neutral wire N. At this time, the short-circuit current flowing between the odd-tap selector T1 and the even-tap selector T2 is limited by the current-limiting resistor R.

[0023] Finally, the vacuum valve M1 is opened. As a result, the first circuit 121 is interrupted by the vacuum valve M1 (and consequently, the circuit between the odd tap selector T1 and the neutral wire N is interrupted by the vacuum valves M1, M2 and switch 2), thus completing the switch from the odd tap to the even tap.

[0024] When the connection destination of the movable contact 23 is switched from the fixed contact 22 to the fixed contact 21, the vacuum valve M1 is closed first. As a result, the circuit between the odd-numbered tap selector T1 and the neutral wire N is energized through the first circuit 121. The load current continues to flow between the even-numbered tap selector T2 and the neutral wire N. At this time, the short-circuit current generated by the short circuit between the odd-numbered tap selector T1 and the even-numbered tap selector T2 is limited by the current-limiting resistor R.

[0025] Next, the vacuum valve M2 is opened. As a result, the circuit between the even-tap selector T2 and the neutral wire N is interrupted by the vacuum valve M2. The load current flows between the odd-tap selector T1 and the neutral wire N through the first circuit 121.

[0026] Next, the movable contact 23 is connected to the fixed contact 21. As a result, the circuit between the even tap selector T2 and the neutral wire N is interrupted by the switch 2, and the movable contact 23 is connected to the odd tap selector T1. However, since the vacuum valve M2 is open, the second circuit 122 is not energized. Therefore, it is possible to prevent arc generation when the movable contact 23 is connected to the fixed contact 21.

[0027] Finally, the vacuum valve M2 is closed. As a result, the switching from the even tap to the odd tap is completed. The load current flowing between the odd tap selector T1 and the neutral wire N mainly passes through the second circuit 122.

[0028] As described above, the movable contact 23 is alternately connected to the fixed contacts 21 and 22, thereby switching between odd-numbered and even-numbered taps alternately. When the connection destination of the movable contact 23 is switched, the tap 11a connected to the neutral wire N is switched. When the tap 11a corresponding to the load of the transformer TR is connected to the neutral wire N, the transformation ratio of the transformer TR is switched to the transformation ratio corresponding to the load of the transformer TR. Moreover, the main winding W and the neutral wire N of the transformer TR are always connected to each other. Therefore, even when the tap 11a is switched, the load current continues to flow between the main winding W and the neutral wire N of the transformer TR.

[0029] Figure 2 is a cross-sectional view of the energy storage device 13, Figure 3 is a side view of the energy storage device 13, Figure 4 is a cross-sectional view along line IV-IV in Figure 2, Figure 5 is a schematic diagram showing the state in which the biasing force is released and the energy storage case 52 moves to the left, Figure 6 is a schematic diagram showing the state in which the movable case 43 moves to the right and energy is stored, and Figure 7 is a schematic diagram showing the state in which the biasing force is released and the energy storage case 52 moves to the right. The energy storage device 13 comprises a drive shaft 31, support shafts 41, 41, guide shafts 51, 51, energy storage member 42, movable case 43, eccentric cam 44, energy storage case 52, vacuum valve opening / closing cam 61, vacuum valve opening / closing mechanism 62, and stopper 63. For the sake of drawing convenience, only one vacuum valve M1 is shown, but in reality, multiple vacuum valves M1, M2, ... are arranged around the vacuum valve opening / closing cam 61.

[0030] For the sake of explanation, the direction in the load-operated tap changer is defined as follows: The movable case 43 can reciprocate along the support shafts 41, 41, and the direction of movement of the movable case 43 (lateral direction or left-right direction in Figures 2 and 4) is referred to as the lateral direction or left-right direction. The support shafts 41, 41 and the guide shafts 51, 51 are arranged parallel to each other on approximately the same plane, and the direction in which the support shafts 41, 41 and the guide shafts 51, 51 are aligned (horizontal direction in Figure 3, vertical direction in Figure 4) is called the front-to-back direction. The drive shaft 31 is positioned in a direction substantially perpendicular to the plane on which the support shafts 41, 41 and guide shafts 51, 51 are arranged side by side. This direction (the up-and-down direction in Figures 2 and 3) is referred to as the up-and-down direction.

[0031] As shown in Figures 2 and 4, both ends of the two support shafts 41, 41 are supported by two support members 35, 35. The support members 35, 35 are wall-shaped members provided on a substrate (not shown), and they support the support shafts 41, 41 so that their axial directions are oriented laterally and they are aligned in the front-to-back direction.

[0032] A drive shaft 31 is positioned between the two support members 35, 35, approximately in the center in the lateral and front-to-back directions, with its axis of rotation facing vertically. The drive shaft 31 is rotatably supported, for example, on a base plate (not shown). The drive shaft 31 is the shaft for driving the tap selector 11 and the changeover switch 12. The drive force from the motor 10 is input to the drive shaft 31, and it rotates due to the input drive force.

[0033] The drive shaft 31 is provided with a grooved cam (not shown). The grooved cam rotates in conjunction with the rotation of the drive shaft 31, driving the movable contact 23 of the switch 2, which in turn switches the connected fixed contacts 21 and 22. Furthermore, the drive shaft 31 is connected to the tap selector 11 via a Geneva mechanism (not shown) that converts continuous rotational motion into intermittent rotational motion. The driving force input to the drive shaft 31 is transmitted to the tap selector 11 via the Geneva mechanism, and the tap 11a to which the tap selector 11 is connected is switched. Furthermore, the driving force input to the drive shaft 31 is stored in the energy storage member 42, as will be described later, and the vacuum valve M1 opens and closes upon the release of the stored biasing force. The details of the energy storage and opening / closing mechanism of the vacuum valve M1 will be described below.

[0034] Two support shafts 41, 41 each support energy storage members 42, 42. The energy storage members 42, 42 are, for example, coil springs that store energy by compression, and the support shafts 41, 41 are inserted through them. The energy storage members 42, 42 are members that store the rotational force of the drive shaft 31 as a biasing force.

[0035] Furthermore, a movable case 43 that compresses the energy storage member 42 is supported on the two support shafts 41, 41 so as to be movable in the lateral direction. As shown in Figure 2, the movable case 43 is a member with an inverted U-shaped cross-section, and has a top plate 431 that is rectangular in plan view, and side walls 432, 432 that extend downward from both left and right ends of the top plate 431. The side walls 432, 432 have holes through which the support shafts 41, 41 slide. The movable case 43 is guided by the support shafts 41, 41 and can reciprocate in the lateral or left-right direction. The energy storage members 42, 42 are arranged inside the movable case 43, that is, between the side walls 432, 432.

[0036] The top plate 431 of the movable case 43 has a lateral elongated hole 431a formed therein, through which the drive shaft 31 passes, and which allows the movable case 43 to move laterally without interfering with the drive shaft 31. The drive shaft 31, which protrudes upward from the movable case 43, is provided with a disc-shaped eccentric cam 44 that rotates with the drive shaft 31 and causes the movable case 43 to reciprocate. The drive shaft 31 passes through a portion of the eccentric cam 44 that is spaced away from its center, and the eccentric cam 44 rotates eccentrically as the drive shaft 31 rotates. On both the lateral sides of the top plate 431 of the movable case 43, there are two protruding bodies 433 that extend in the front-rear direction and contact the lateral ends of the eccentric cam 44, respectively. When the eccentric cam 44 rotates due to the drive shaft 31, the movable case 43 moves laterally as shown in Figures 2 and 6.

[0037] As shown in Figures 2 and 4, both ends of the two guide shafts 51, 51 are supported by two support members 35, 35. The support members 35, 35 support the guide shafts 51, 51 so that their axial directions are oriented laterally and they are aligned in the front-to-back direction. The guide shafts 51, 51 are positioned inside the two support shafts 41, 41 in the front-to-back direction.

[0038] Furthermore, the two guide shafts 51, 51 support a laterally movable energy storage case 52, which is capable of moving back and forth by the biasing force released by the energy storage member 42. The energy storage case 52 can move relative to the movable case 43 in the same direction as the reciprocating movement of the movable case 43. As shown in Figure 2, the energy storage case 52 is a U-shaped member in cross-section, and has a rectangular bottom plate 521 in plan view, and side walls 522, 522 extending upward from both left and right ends of the bottom plate 521. The side walls 522, 522 have holes through which the guide shafts 51, 51 slide. The energy storage case 52 can reciprocate laterally or left and right, guided by the guide shafts 51, 51. In addition, the side walls 522, 522 are formed so that the energy storage case 52 can move without interfering with the movable case 43, and so that the ends of the energy storage members 42, 42 do not pass through laterally. For example, the side walls 522, 522 have concave portions that conform to the convex portions through which the support shafts 41, 41 pass. The energy storage member 42 is positioned between the left side wall 522 of the energy storage case 52 and the right side wall 432 of the movable case 43. Since the width of the concave portion of the side walls 522, 522 in the front-rear direction is smaller than the diameter of the energy storage member 42, the energy storage member 42 is sandwiched between the side wall 432 of the movable case 43 and the side wall 522 of the energy storage case 52, as shown in Figure 2.

[0039] The bottom plate 521 of the energy storage case 52 has a lateral elongated hole 521a formed therein, through which the drive shaft 31 passes, and which allows the energy storage case 52 to move laterally without interfering with the drive shaft 31.

[0040] Below the energy storage case 52 is a disc-shaped vacuum valve opening / closing cam 61 that rotates in conjunction with the forward and backward movement of the energy storage case 52. A hole 61a is formed in the center of the vacuum valve opening / closing cam 61 through which the drive shaft 31 passes. The vacuum valve opening / closing cam 61 rotates coaxially with the drive shaft 31. The energy storage case 52 is provided with a drive roller (drive member) 523 for rotating the vacuum valve opening / closing cam 61. Specifically, the drive roller 523 is provided on the front part of the bottom plate 521 of the energy storage case 52, approximately in the center in the front-rear direction. The drive roller 523 has a shaft portion that protrudes downward from the bottom plate 521 and an outer ring attached to the shaft portion. A groove 61b is formed on the upper surface of the vacuum valve opening / closing cam 61 into which the drive roller 523 fits. The groove 61b is long in the radial direction of the vacuum valve opening / closing cam 61, and when the energy storage case 52 moves laterally, the vacuum valve opening / closing cam 61 rotates. As the vacuum valve opening / closing cam 61 rotates, the drive roller 523 moves along the groove 61b. Although a drive roller 523 having a roller was described as an example of a configuration for rotating the vacuum valve opening / closing cam 61 by the reciprocating movement of the energy storage case 52, a drive member having a pointed end or a flat end, such as a pin, may also be provided as a contact element that contacts the vacuum valve opening / closing cam 61.

[0041] The vacuum valve opening / closing mechanism 62 includes a cam follower 621 that is driven by the rotation of the vacuum valve opening / closing cam 61 and drives the changeover switch 12. The cam follower 621 is supported on one end of a swing bar 622, which is swingably supported by a pivot 623. The cam follower 621 has a roller that contacts the lower surface of the vacuum valve opening / closing cam 61 and rolls along its circumference, and the roller is connected to one end of the swing bar 622 by a mounting shaft. At the other end of the swing bar 622, an electrode terminal 625 extending upward from the movable electrode of the vacuum valve M1 is supported by a shaft 624.

[0042] The vacuum valve opening / closing cam 61 has an inclined portion 61d whose thickness changes along the circumferential direction, such that the cam follower 621 moves in the axial direction of the drive shaft 31 according to the rotational position of the vacuum valve opening / closing cam 61. Here, a cam in which the inclined portion 61d is formed on the disc surface of the vacuum valve opening / closing cam 61 is described as an example, but the type of cam is not particularly limited. The vacuum valve opening / closing cam 61 may be a grooved cam formed on the circumferential surface of the vacuum valve opening / closing cam 61, an end face cam formed at the circumferential end, an inclined cam, a conical cam, other three-dimensional cams, or a planar cam. As long as it can open and close the vacuum valve M1, the shape and configuration of the vacuum valve opening / closing cam 61 are not particularly limited.

[0043] As the energy storage case 52 moves and the vacuum valve opening / closing cam 61 rotates, the cam follower 621 moves vertically. As the cam follower 621 moves vertically, the electrode terminal 625 pivotally supported on the other end of the swing bar 622 moves up and down, opening and closing the vacuum valve M1.

[0044] Two stoppers 63 are provided on the radially outer and lateral sides of the vacuum valve opening / closing cam 61. The stoppers 63 are levers that can rotate in both forward and reverse directions. The stopper 63 comprises a stopper body 631 supported by a support shaft 632, an engaging roller 633, and a release operation part 634. The engaging roller 633 is supported on one end of the stopper body 631 and slides on the circumferential surface of the vacuum valve opening / closing cam 61, engaging with and disengaging from the stopper receiver 61c of the vacuum valve opening / closing cam 61. The stopper receiver 61c is a recess provided on a part of the outer circumference of the vacuum valve opening / closing cam 61.

[0045] The stopper 63 is a member that fixes the vacuum valve opening / closing cam 61 by engaging with the vacuum valve opening / closing cam 61 when biasing force is stored in the energy storage member 42. The stopper 63 is biased so that the engaging roller 633 contacts the peripheral edge of the vacuum valve opening / closing cam 61. When the engaging roller 633 is engaged with the stopper receiver 61c, the rotation of the vacuum valve opening / closing cam 61 is prevented. Two stopper receivers 61c are formed on the outer circumference of the vacuum valve opening / closing cam 61. When the engaging roller 633 of the first stopper 63 engages with the first stopper 63, the energy storage case 52 is fixed in the position of one end (right side) in the lateral direction. Movement of the energy storage case 52 to the other end (left side) in the lateral direction is prevented. When the engaging roller 633 of the second stopper 63 engages with the second stopper 63, the energy storage case 52 is fixed in the position of the other end (left side) in the lateral direction. The energy storage case 52 is prevented from moving to one end (right side) in the lateral direction.

[0046] The release operation part 634 is formed on the other end of the stopper body 631. The movable case 43 is provided with an engagement release part 434 for pushing the release operation part 634 and releasing the engagement of the stopper 63. As shown in Figure 2, when the energy storage case 52 is fixed at one end in the lateral direction (right side), when the movable case 43 moves to the other end in the lateral direction (left end) within the range of motion, the release operation part 634 of the first stopper 63 is pushed by the engagement release part 434, and the engagement roller 633 falls out of the stopper receiver 61c. The energy storage case 52 becomes able to move to the left. The biasing force released by the energy storage member 42 causes the energy storage case 52 to move from one end in the lateral direction (right end) to the other end in the lateral direction (left end).

[0047] Similarly, as shown in Figure 6, when the energy storage case 52 is fixed at the other lateral end (left end), when the movable case 43 moves to the lateral end (right end) within the range of motion, the release operation part 634 of the second stopper 63 is pushed by the engagement release part 434, and the engagement roller 633 detaches from the stopper receiver 61c. The energy storage case 52 becomes able to move to the right. The biasing force released by the energy storage member 42 causes the energy storage case 52 to move from the other lateral end (left end) to the lateral end (right end). Although an example in which the release mechanism 434 is provided on the movable case 43 has been described, since the reciprocating movement of the movable case 42 is related to the rotational movement of the output shaft, drive shaft 31, and eccentric cam 44 of the motor 10, the release mechanism 434 may also be provided on the output shaft, drive shaft 31, and eccentric cam 44 of the motor 10, and configured so that the engagement of the stopper 63 is released when the movable case 42 moves laterally to one end or the other end of the movable range. Alternatively, the release mechanism 434 may be provided on the output shaft, drive shaft 31, and eccentric cam 44 of the motor 10 via any power transmission mechanism, and configured so that the engagement of the stopper 63 is released when the movable case 42 moves laterally to one end or the other end of the movable range.

[0048] The operation of the load tap changer 1 configured in this way, particularly the opening and closing operation of the vacuum valve M1, will now be explained. The rotational driving force of the drive shaft 31 drives the tap selector 11 and the switch 2, and the rotational driving force is stored in the energy storage device 13 by the compression of the energy storage member 42.

[0049] In the state shown in Figure 2, where biasing force is stored in the energy storage member 42, when the movable case 43 moves further to the left, the first stopper 63 is released by the engagement release part 434, and the energy storage case 52 becomes able to move to the left. As shown in Figures 2 and 5, the biasing force released by the energy storage member 42 causes the energy storage case 52 to move from one end (right end) to the other end (left end) in the lateral direction. When the energy storage case 52 moves in this way, the vacuum valve opening / closing cam 61 rotates, the inclined part 61d moves the cam follower 621 downward, and the vacuum valve M1 opens.

[0050] In the state shown in Figure 5, where the energy storage member 42 has released its biasing force, the energy storage case 52 is prevented from moving by the second stopper 63. When the movable case 43 moves from left to right as shown in Figure 6, the energy storage member 42 is compressed, and the rotational driving force of the drive shaft 31 is accumulated as a biasing force.

[0051] In the state shown in Figure 6, where biasing force is stored in the energy storage member 42, when the movable case 43 moves further to the right, the second stopper 63 is released by the engagement release part 434, and the energy storage case 52 becomes able to move to the right. As shown in Figures 6 and 7, the biasing force released by the energy storage member 42 causes the energy storage case 52 to move from the other end (left end) to the one end (right end) in the lateral direction. When the energy storage case 52 moves in this way, the vacuum valve opening / closing cam 61 rotates, the cam follower 621 moves upward, and the vacuum valve M1 closes.

[0052] In the state shown in Figure 7, where the energy storage member 42 has released its biasing force, the energy storage case 52 is prevented from moving by the first stopper 63. When the movable case 43 moves from the right side to the left side from the state shown in Figure 7, as shown in Figure 2, the energy storage member 42 is compressed, and the rotational driving force of the drive shaft 31 is accumulated as a biasing force. Thereafter, the rotational driving force of the drive shaft 31 can be used to directly drive the vacuum valve opening / closing cam 61, thereby opening and closing the vacuum valve M1.

[0053] As described above, the on-load tap changer 1 and on-load tap changer transformer according to this embodiment allow the tap selector 11 and the changeover switch 12 to be driven with a simple configuration that reduces the number of parts.

[0054] Specifically, by fitting a drive roller 523 provided on the energy storage case 52 into a groove 61b on the vacuum valve opening / closing cam 61 and driving it directly, the drive system for driving the tap selector 11 and the changeover switch 12 can be consolidated into a single unit. This eliminates the need for the crank and hollow shaft found in conventional on-load tap changing devices, enabling a slimmer overall drive system mechanism and cost reduction.

[0055] More specifically, a drive roller 523 provided on the energy storage case 52 fits into a groove 61b of the vacuum valve opening / closing cam 61, and the reciprocating movement of the energy storage case 52 can directly rotate the vacuum valve opening / closing cam 61. In addition, the rotation of the vacuum valve opening / closing cam 61 causes the cam follower 621 to move up and down, thereby opening and closing the vacuum valve. In this way, it is possible to slim down the entire drive system mechanism and reduce costs.

[0056] Since the movable case 43 and the energy storage case 52 have elongated holes 431a and 521a through which the drive shaft 31 passes, the vacuum valve opening / closing cam 61 can be positioned directly below the movable case 43 and the energy storage case 52, allowing the load-operated tap changer to be made slimmer.

[0057] Furthermore, the storage and release of energy in the energy storage member 42 can be controlled with a simple configuration consisting of an engagement release part 434 provided on the movable case 43, a stopper receiver 61c provided on the vacuum valve opening / closing cam 61, and a stopper 63.

[0058] In this embodiment, an example was described in which a groove 61b is provided on the vacuum valve opening / closing cam 61 and a drive roller 523 is provided on the energy storage case 52. However, a groove may be provided on the energy storage case 52 and a drive roller 523 may be provided on the vacuum valve opening / closing cam 61.

[0059] Furthermore, although an example was described in which the disc surface of the vacuum valve opening / closing cam 61 is inclined so that the cam follower 621 rolls on the disc surface, a cam may also be formed on the outer circumferential surface of the vacuum valve opening / closing cam 61 so that the cam follower 621 rolls on the outer circumferential surface.

[0060] Furthermore, the vertical positional relationship of the motor 10, tap selector 11, and energy storage device 13 is just one example, and the positional relationship is not particularly limited as long as the tap selector 11 and the changeover switch 12 are driven.

[0061] Furthermore, although vacuum valves M1 and M2 were described as the shut-off switches provided in the changeover switch 12, they may be configured with any other shut-off switches. [Explanation of Symbols]

[0062] 1: Tap changer under load, 2: Switch, 10: Motor, 11: Tap selector, 12: Changeover switch, 13: Energy storage device, 31: Drive shaft, 42: Energy storage member, 43: Movable case, 44: Eccentric cam, 52: Energy storage case, 61: Vacuum valve opening / closing cam, 61a: Hole, 61b: Groove, 61c: Stopper receiver, 61d: Inclined part, 63: Stopper, 431a: Slotted hole, 433: Protruding strip, 434: Release part, 521a: Slotted hole, 523: Drive roller, 621: Cam follower, 634: Release operation part, M1, M2: Vacuum valve, TR: Transformer

Claims

1. An on-load tap changer comprising a tap selector and a changeover switch, A drive shaft for driving the tap selector, An energy storage member that stores the rotational force of the drive shaft as a biasing force, A power storage case that can move forward and backward by the biasing force released by the power storage member, A cam that rotates in conjunction with the forward and backward movement of the energy storage case, A cam follower that is driven by the rotation of the cam and drives the changeover switch and A tap changer equipped with an on-load mechanism.

2. The energy storage case is equipped with a drive member for rotating the cam, The cam is provided with a groove into which the drive member fits. The on-load tap changer according to claim 1.

3. The cam has an inclined portion formed along its circumferential direction such that the cam follower moves in the axial direction of the drive shaft according to the rotational position of the cam. The aforementioned changeover switch is, The system includes a vacuum valve that opens and closes in conjunction with the movement of the cam follower. The on-load tap changer according to claim 1.

4. The energy storage case has an elongated hole through which the drive shaft passes, allowing the energy storage case to reciprocate. The on-load tap changer according to claim 1.

5. With biasing force stored in the energy storage member, a stopper that fixes the cam by engaging with the cam, A movable case moves relative to the energy storage case in the same direction as the reciprocating movement of the energy storage case, and compresses the energy storage member. When the movable case moves to one end or the other end of the range of motion, an engagement release part releases the engagement of the stopper with respect to the cam. The on-load tap changer according to claim 1, comprising:

6. Transformer and, The on-load tap changer described in claim 1 and Equipped with, The transformer's voltage ratio is switched by the on-load tap changer. On-load tap-changing transformer.

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