JP2010258266A - Tap switching device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tap switching device that can be made compact. <P>SOLUTION: A changeover switch 22 of the tap switching device 101 includes an output member 89 which rotates on a predetermined axis 71, a plurality of fixed contacts 63 electrically connected to different taps, respectively, a movable contact 81 which operates as the output member 89 rotates to selectively connect with the plurality of fixed contacts 63, a first vacuum valve VSR connected between a predetermined node and a current limiting resistance R, and a second vacuum valve VSM connected between the predetermined node and the movable contact 81, wherein the movable contact 81, the plurality of fixed contacts 63, the first vacuum valve VSR, and the second vacuum valve VSM are provided crossing the same plane orthogonal to the predetermined axis 71, and the movable contact 81 is provided inside the plurality of fixed contacts 63, the first vacuum valve VSR, and the second vacuum valve VSM in a radial direction centering on the predetermined axis 71. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a tap switching device, and more particularly to a tap switching device using an auxiliary contact.

  A load tap-changer (LTC: Load Tap-Changer) is used in order to switch the turns ratio of the transformer without a power failure while the load is connected to the transformer (for example, Japanese Patent Laid-Open No. 59-208814). (See Japanese Patent Publication (Patent Document 1), Japanese Patent Publication No. 4-7084 (Patent Document 2), Japanese Patent Publication No. 11-504755 (Patent Document 3), and Japanese Patent Application Laid-Open No. 60-47405 (Patent Document 4)). The on-load tap switching device includes a tap selector that selects a tap provided on the coil of the transformer, and a switching switch that switches a load current path when switching tap selection. This switching switch is placed in an insulating medium such as insulating oil in order to switch the load current path in an insulating atmosphere.

  The switching switch includes a current limiting resistor for limiting the bridging current at the time of tap switching and a vacuum valve that is a current switching element. From the number of current limiting resistors used per phase and the number of vacuum valves used There are methods such as a 1-resistance 2-valve, a 1-resistance 3-valve, and a 2-resistance 4-valve.

  For switching switches that require compactness, it is better to have a small number of vacuum valves whose storage efficiency is not so good. For this reason, the 1 resistance 2 valve with the smallest number of vacuum valves is most advantageous.

  As an example of a 1-resistor 2-valve LTC, for example, Japanese Patent Publication No. 60-40691 (Patent Document 5) discloses a make-after-break type structure composed of two energizing fixed contacts and one energizing movable contact. Auxiliary contacts are disclosed.

  Further, a specific circuit in LTC of one resistance and two valves is disclosed in Japanese Patent Publication No. 60-40692 (Patent Document 6) and Japanese Patent No. 3356446 (Patent Document 7).

JP 59-208814 A Japanese Examined Patent Publication No. 4-7084 Japanese National Patent Publication No. 11-504755 JP-A-60-47405 Japanese Patent Publication No. 60-40691 Japanese Patent Publication No. 60-40692 Japanese Patent No. 3356446

  By the way, in LTC, it is necessary to mechanically operate a vacuum valve unit including a plurality of vacuum valves and an auxiliary contact unit for switching the vacuum valves without interruption. Electrically, it is necessary for the LTC to have an insulation strength that can withstand a voltage that is constantly applied between the odd-numbered and even-numbered taps. In the LTCs described in Patent Documents 6 and 7, in order to easily achieve these, the vacuum valve unit and the auxiliary contact unit are arranged in two upper and lower stages, respectively, and a margin for space is provided. However, such a configuration has a problem that the switching switch becomes long and large.

  More specifically, since the voltage is always applied between the fixed contacts corresponding to the odd-numbered and even-numbered taps as described above, it is necessary to insulate the odd-numbered and even-numbered fixed contacts, A predetermined insulation distance must be secured. For example, in the LTC described in Patent Document 7, this insulation distance depends on the arrangement radius and the arrangement gap angle of the fixed contacts arranged on the circumference.

  Moreover, LTC is often used for a three-phase AC transformer, and in this case, a switching opening / closing mechanism of one resistance and two valves is required for three phases. The LTC described in Patent Document 7 has a configuration in which a switching opening / closing mechanism for three phases is connected to a neutral point that does not require interphase insulation, and each switching opening / closing mechanism is arranged on the circumference of the same plane. It has been.

  For this reason, the switching open / close mechanism of the one-resistance two-valve for one phase needs to be included in an angular range within 120 ° that is divided into three equal circumferences. That is, when three phases are arranged on the circumference, the operation range for one phase (the angle of the range in which the movable contact performs forward / reverse rotational movement) is 120 ° or less. Furthermore, from the operating range within 120 °, the remaining interval between the fixed contacts in the remaining interval after subtracting the operating interval of the vacuum valve and the interval allowing for the arc generation when the current is interrupted by the opening of the vacuum valve. A switch must be made.

  Therefore, in order to secure a necessary insulation distance between the odd-numbered and even-numbered fixed contacts, it is necessary to increase the arrangement radius of the fixed contacts. However, when the arrangement radius is increased, the diameter of the switching switch is increased, and it is necessary to make the switching switch container made of an insulating material having a large diameter which is disadvantageous in terms of manufacturing and cost.

  In order to avoid such a problem, a minimum arrangement radius that can secure a distance required by each of the vacuum valve unit and the auxiliary contact unit is set, and as described in Patent Documents 6 and 7, A method of reducing the diameter of the switching switch container by arranging the unit and the auxiliary contact unit in two upper and lower stages is practically used.

  However, since the switching switch becomes longer when the diameter of the switching switch container is reduced, the LTC becomes longer as a whole, and there is a problem that enlargement of the LTC is inevitable.

  In the LTC described in Patent Document 1, the main contact vacuum switch and the auxiliary contact vacuum switch are arranged on the same plane, but the auxiliary contact used in the one-resistance two-valve system, that is, the fixed contact and the movable contact described above. No contact point is disclosed. Further, since the vacuum switch for main contacts and the vacuum switch for auxiliary contacts are simply arranged on the circumference, the diameter of the switching switch increases as the number of these switches increases.

  This invention was made in order to solve the above-mentioned subject, and the objective is to provide the tap switching device which can achieve size reduction.

  In order to solve the above-described problems, a tap switching device according to an aspect of the present invention is a tap switching device for switching a turns ratio of a transformer including a coil, the casing being filled with an insulating medium, and the casing. A tap selector that is provided outside the body and selects at least one tap from a plurality of taps provided at a plurality of positions in the coil included in the transformer, and is provided in the housing and selected by the tap selector. Including a contact point through which a load current flows between the tap and a predetermined node, and a switching switch that opens and closes the contact point. The switching switch includes an output member that rotates about a predetermined axis, A plurality of fixed contacts that are electrically connected to the different taps via a tap selector, and actuated with the rotation of the output member. A movable contact to be connected; a current limiting resistor connected to one of the plurality of fixed contacts; a first vacuum valve connected between the predetermined node and the current limiting resistor; the predetermined node and the movable A second vacuum valve connected between the contacts, wherein the movable contact, the plurality of fixed contacts, the first vacuum valve, and the second vacuum valve are on the same plane orthogonal to the predetermined axis. The movable contacts are provided so as to cross each other, and are provided inward of the plurality of fixed contacts, the first vacuum valve, and the second vacuum valve in a radial direction about the predetermined axis.

  According to the present invention, downsizing can be achieved.

It is sectional drawing which shows the structure of the tap switching apparatus at the time of embodiment which concerns on this invention. It is sectional drawing which shows the principal part of the switching switch in the tap switching apparatus at the time of loading shown in FIG. It is sectional drawing of the switching switch along the III-III line in FIG. (A)-(e) is a figure which shows the opening / closing operation | movement of the fixed contact and movable contact for 1 phase in a switching switch in time series. (A)-(i) is a figure which shows the operation | movement at the time of the switching switch which concerns on embodiment of this invention switching a contact. It is a figure which shows the operation | movement sequence of each part in a switching switch.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

FIG. 1 is a cross-sectional view showing a configuration of a load tap changer according to an embodiment of the present invention.
Referring to FIG. 1, on-load tap switching device 101 includes a tap selector 21, a switching switch container 23 as a housing filled with an insulating medium, for example, insulating oil, and a switching switch disposed in the switching switch container 23. And a switch 22. The switching switch 22 includes a contact (switch) 60 through which a load current flows, and opens and closes the contact 60. The contact 60 corresponds to vacuum valves VSM and VSR described later.

  The tap selector 21 is disposed outside the switching switch container 23 and selects at least one tap from a plurality of taps provided at a plurality of positions in the coil (winding) 11 included in the transformer 10. The tap selector 21 electrically connects the selected tap and a fixed contact provided corresponding to the tap in the switching switch 22 described later. The tap selector 21 is accommodated together with the coil 11 in a transformer tank 13 filled with insulating oil.

  The switching switch 22 is electrically connected to the tap selector 21 and has a contact 60 through which a load current flows between the tap selected by the tap selector 21 and a predetermined node such as the output side terminal of the coil 11. Have. The switching switch 22 opens and closes the contact 60 to switch the current path between each tap selected by the tap selector 21 and the output side terminal of the coil 11 when the tap of the coil 11 is switched. The load current flowing between each tap selected by the tap selector 21 and the output side terminal of the coil 11 is turned on / off. Here, for example, when the coil 11 is a three-phase coil, the output-side terminal of the coil 11 is a neutral point of the three-phase coil.

  The on-load tap switching device 101 is connected to the driving device 24 and attached to the transformer 10. Outside the transformer 10, a driving device 24 for driving the switching switch 22 and the tap selector 21 is provided. The drive device 24 includes an electric operation mechanism unit 27 that houses a motor that is a drive source, and a drive force transmission unit 25 that transmits a drive force from the electric operation mechanism unit 27 to the switching switch 22 and the tap selector 21.

  Next, an example of tap switching performed by the on-load tap switching device 101 will be briefly described.

  The tap selector 21 selects the first tap and the second tap from the state where only the first tap is selected from the plurality of taps provided at the plurality of positions in the coil 11 included in the transformer 10. The state is switched to the state where the first tap and the second tap are selected, and the state where only the second tap is selected is switched from the state where the first tap and the second tap are selected.

  The switching switch 22 is connected to the first tap via the contact 60 before the tap selector 21 switches from the selection state of the first tap and the second tap to the selection state of only the second tap. The electrical connection between the output side terminal of the coil 11 is switched to the electrical connection between the output side terminal of the coil 11 and the second tap via the contact 60. Here, the switching switch 22 creates a bridge state in which the output side terminal of the coil 11 and both the first tap and the second tap are connected via a current limiting resistor, thereby forming the first tap. The load current path is switched so that the electrical connection via the contact 60 between at least one of the second taps and the output side terminal of the coil 11 is not interrupted.

  In this way, the on-load tap switching device 101 switches the tap ratio provided on the coil 11 of the transformer 10 during load operation, thereby switching the turns ratio of the transformer 10 without an uninterruptible power. Adjust the voltage.

  Next, the structure of the on-load tap switching device 101 according to the embodiment of the present invention will be described in detail.

  2 is a cross-sectional view showing the main part of the switching switch in the on-load tap switching device shown in FIG.

  Referring to FIG. 2, switching switch 22 includes an energy storage mechanism 57, an output shaft 58, an auxiliary contact unit 73, and a vacuum valve unit 74. The auxiliary contact unit 73 includes an output member 89 and an auxiliary contact 91. The auxiliary contact 91 includes a fixed contact 63 and a movable contact 81. The fixed contact 63 includes a spring 64 and a connection portion 65. The connecting portion 65 is a portion that repeats contact and non-contact with the movable contact 81 as the movable contact 81 rotates. The energy storage mechanism 57 is formed of a spring. The energy storage mechanism 57 is connected to the driving force transmission unit 25 shown in FIG. 1 through a gear and a driving shaft (not shown). The output member 89 is provided so as to be rotatable about a central axis 71 that is a virtual axis. The output member 89 is connected to the energy storage mechanism 57 via the output shaft 58.

  The power energy input from the driving force transmission unit 25 through a gear and a driving shaft (not shown) is stored in the energy storage mechanism 57 as a spring force. When necessary power energy is stored in the energy storage mechanism 57, the energy storage mechanism 57 operates a restraining claw provided on the output shaft 58, and releases the stored power energy to the output shaft 58 at once. As a result, the output member 89 rotates about the central axis 71.

  As indicated by the arrows in FIG. 2, the bell crank 72 reciprocates left and right as the output shaft 58 rotates, that is, reciprocates in the radial direction around the central shaft 71. As a result, as indicated by the arrows in FIG. 2, the shaft connected to the vacuum valve unit 74 reciprocates up and down, and each vacuum valve in the vacuum valve unit 74 repeats opening and closing.

  3 is a cross-sectional view of the switching switch along the line III-III in FIG. Referring to FIG. 3, auxiliary contact 91 includes three sets of fixed contacts 63OD (fixed contacts 63ODU, 63ODV, 63ODW) and fixed contacts 63EV of U phase, V phase, and W phase provided on the switching switch container 23 side. (Fixed contacts 63EVU, 63EVV, 63EVW) and three movable contacts 81U, 81V, 81W of U phase, V phase, and W phase provided on the output member 89 side. The fixed contacts 63ODU, 63ODV, 63ODW are provided corresponding to odd taps in the U-phase, V-phase, and W-phase coils in the transformer 10, respectively. The fixed contacts 63EVU, 63EVV, 63EVW are provided corresponding to even taps in the U-phase, V-phase, and W-phase coils in the transformer 10, respectively.

  The fixed contacts 63ODU, 63EVU, 63ODV, 63EVV, 63ODW, 63EVW are arranged in this order at intervals in the circumferential direction with the central axis 71 as the center. Each fixed contact 63 is electrically connected to a corresponding tap via the tap selector 21 shown in FIG.

  The movable contacts 81U, 81V, 81W are arranged inside the fixed contacts 63 in the radial direction centered on the central axis 71, and are arranged to face the corresponding fixed contacts 63OD and 63ED. The movable contacts 81U, 81V, 81W are operated in accordance with the rotation of the output member 89, and selectively connect to the fixed contacts 63OD and 63ED of the corresponding phase.

  The switching switch 22 includes three sets of vacuum valves VSM (VSMU, VSMV, VSMW) and VSR (VSRU, VSVR, VSRW) of U phase, V phase, and W phase.

  The vacuum valves VSM and VSR are arranged between the fixed contacts 63OD and 63EV of the corresponding phase. The vacuum valves VSMU, VSRU, VSMV, VSLV, VSMW, and VSRW are arranged in this order at intervals in the circumferential direction around the central axis 71.

  Each movable contact 81, each fixed contact 63, and each vacuum valve are provided so as to intersect with the same plane orthogonal to the central axis 71.

  Each movable contact 81 is provided inside each fixed contact 63, each vacuum valve VSR, and each vacuum valve VSM in the radial direction centering on the central axis 71. Further, the connection portion 65 of the fixed contact 63 is provided on the inner side of the vacuum valve VSR and the vacuum valve VSM in the radial direction with the central axis 71 as the center.

  The rotational movement of the output member 89 is transmitted to each movable contact 81. That is, when the motive energy is released from the energy storage mechanism 57 to the output shaft 58, each movable contact 81 rotates or swings with the seesaw as the output member 89 rotates. As a result, the fixed contacts 63OD and 63ED and the movable contact 81 are alternately in contact with each other, and a load current flows through the contacted fixed contact 63.

  The fixed contact 63 is pushed in the direction of the movable contact 81 by the spring 64 when the movable contact 81 is inserted into the fixed contact 63, that is, when the movable contact 81 contacts the fixed contact 63. Thus, pressure can be applied to the contact between the fixed contact 63 and the movable contact 81, and the fixed contact 63 and the movable contact 81 can be brought into stable contact.

  As described above, in the on-load tap switching device according to the embodiment of the present invention, the surplus formed inside the six vacuum valves (2 valves × 3 phases) arranged in the circumferential direction around the central axis 71. The auxiliary contact unit 73 is disposed in the space. With such a configuration, the storage space of the conventional LTC in which the vacuum valve unit and the auxiliary contact unit are arranged in two upper and lower stages can be reduced to only one storage space by omitting the space for one stage. . As a result, the length of the switching switch is shortened, and a compact 1-resistor 2-valve switching switch with improved integration efficiency can be realized. Therefore, a small and low-cost LTC can be provided. In addition, the weight of the switching switch can be reduced, and the lifting dimension can be reduced by shortening the overall length of the switching switch, so that the efficiency of maintenance can be improved.

  Here, in the conventional LTC, it is necessary to increase the arrangement radius of the fixed contacts in order to ensure a necessary insulation distance between the odd-numbered and even-numbered fixed contacts. When the arrangement radius of the fixed contacts is increased, a large-diameter switching switch container having a cost higher than that of the vertically long is required. In addition, when the arrangement radius of the fixed contacts is increased, the transformer is enlarged in order to secure an insulation distance between the switching switch and the coil of the transformer. On the other hand, in the on-load tap switching device according to the embodiment of the present invention, the insulation distance S between the odd-numbered fixed contact 63OD and the even-numbered fixed contact 63EV can be secured with a small array radius R.

  In the on-load tap switching device according to the embodiment of the present invention, the auxiliary contact 91 is provided in the form of the fixed contacts 63OD and 63ED and the movable contact 81 in each phase as shown in FIGS. Although two sets are provided with a space in the axial direction of the central shaft 71, the present invention is not limited to this. In each phase, one set of fixed contacts 63OD and 63ED and one movable contact 81 may be provided, or three or more sets may be provided.

  FIGS. 4A to 4E are diagrams showing the switching operation of the fixed contact and the movable contact for one phase in the switching switch in time series.

  Referring to FIG. 4, output member 89 includes a cam roller 82, a drive arm 83, and an output shaft 58. The movable contact 81 has a rotating shaft 85 and an arm portion 88OD and an arm portion 88EV provided to face the fixed contact 63OD and the fixed contact 63EV, respectively.

  Three drive arms 83 are provided corresponding to the U-phase, V-phase, and W-phase movable contacts 81U, 81V, and 81W, and the three drive arms 83 extend radially from the output shaft 58. That is, each drive arm 83 extends in the radial direction about the central axis 71.

  Three cam rollers 82 are provided corresponding to the drive arms 83 of each phase, and are attached to the tips of the corresponding drive arms 83, that is, on the side opposite to the output shaft 58. The cam roller 82 reciprocates along the circumferential direction about the central axis 71 while rolling with respect to the movable contact 81 with the rotational movement of the drive arm 83 due to the rotational movement of the output shaft 58.

  The movable contact 81 is rotatably supported between the arm portion 88OD and the arm portion 88EV, receives the reciprocating movement of the cam roller 82, the arm portion 88OD contacts the fixed contact 63OD, and the arm portion 88EV is fixed contact 63EV. The arm portion 88OD is separated from the fixed contact 63OD, and the arm portion 88EV is swung between the second position where the arm portion 88EV contacts the fixed contact 63EV.

  The movable contact 81 extends along a circumferential direction centering on the central axis 71, and when the cam roller 82 is positioned at the moving end on the first position side and the second position side, A cam surface 87 having a first end portion EG1 and a second end portion EG2 that are in contact with each other is formed.

  The movable contact 81 has a boomerang type cam structure. That is, the movable contact 81 extends while curving around the cam shaft 85. In other words, the movable contact 81 is bent at the cam shaft 85. The movable contact 81 is branched from the cam shaft 85 and extends in the circumferential direction about the central shaft 71. The cam surface 87 of the movable contact 81 faces the output shaft 58.

  At the end of the arm portion 88OD, a portion facing the cam surface 87 is chamfered, and this chamfered portion comes into contact with the fixed contact 81OD. At the end of the arm portion 88EV, a portion facing the cam surface 87 is chamfered, and this chamfered portion comes into contact with the fixed contact 63EV.

  The cam surface 87 of the movable contact 81 is formed over a predetermined angle from the first end EG1 and the second end EG2 in the circumferential direction around the central axis 71, and is movable while the cam roller 82 is in contact. The non-operating region S1 and the non-operating region S3 where the contact 81 is inoperative, and the operating region S2 formed between the non-operating region S1 and the non-operating region S3 and in which the movable contact 81 operates while the cam roller 82 contacts. And divided.

  With such a shape, in the first half and the second half of the rotation operation of the drive arm 83, an idling section is created in which the drive arm 83 does not rotate even if the drive arm 83 rotates. The period from the state of FIG. 4A to the state of FIG. 4B corresponds to the first half of the rotation operation of the drive arm 83, and the state from the state of FIG. 4D to the state of FIG. The period corresponds to the second half of the rotation operation of the drive arm 83.

  The movable contact 81 has an engagement groove 86. That is, the operation area S2 is formed in a groove shape that is recessed in the cam surface 87 as compared with the non-operation area S1 and the non-operation area S3.

  With such a shape, the drive arm 83 rotates in the middle of the rotation operation of the drive arm 83 from the state of FIG. 4B to the state of FIG. 4D, that is, in the range of θ shown in FIG. As a result, the movable contact 81 rotates by an angle β.

  Further, the swing radius r of the movable contact 81 when the movable contact 81 is engaged with the cam roller 82 via the engagement groove 86, that is, the rotational center of the cam roller 82 when the cam roller 82 contacts the operation region S2 and the movable contact 81 are movable. The distance r between the contact 81 and the swing center is smaller than the length L of the drive arm 83, that is, the distance L between the center shaft 71 and the rotation center of the cam roller 82. As a result, the rotation angle β of the movable contact 81 is larger than the rotation angle θ of the cam roller 82 in the middle of the rotation operation of the drive arm 83. That is, since the movable contact 81 can be rotated faster than the drive arm 83, the switching section of the fixed contacts 63OD and 63EV, that is, the rotation angle θ can be reduced. As a result, it is possible to sufficiently obtain a period from when the vacuum valves VSM and VSR are opened to complete energization from the rotation range α of the drive arm 83 that is 120 ° or less. That is, the fixed contacts 63OD and 63EV can be reliably switched within the rotation range α of the drive arm 83 that is 120 ° or less.

  In the on-load tap switching device according to the embodiment of the present invention, since the movable contact 81 has the boomerang-shaped cam structure as described above, as shown in FIG. It moves in the radial direction around the central axis 71 and contacts the fixed contact 63. That is, the insulation distance S is not secured in the circumferential direction around the central axis 71, but the insulation distance S is secured in the radial direction around the central axis 71. Thus, the insulation distance S between the movable contact 81 and the fixed contact 63 can be increased by decreasing the boomerang-shaped angle of the movable contact 81 without increasing the arrangement radius R of the fixed contact 63. That is, it is possible to easily secure the insulation distance between the fixed contacts 63OD and 63EV and the movable contact 81 with a small arrangement radius R. Therefore, the auxiliary contact unit 73 can be made compact.

  When the contact method of the movable contact and the fixed contact is a roller type, that is, when the movable contact has a roller structure, the load torque when driving these contacts does not increase, but the movable contact does not slide, so the contact surface Is never polished. For this reason, with the passage of time, an oxide film or the like is deposited on the contact surface, the contact resistance increases, and an energization failure due to contact overheating may occur.

  On the other hand, when the contact method of the movable contact and the fixed contact is a sliding method, the contact surface is polished by the sliding of the movable contact, so that contact overheating due to increase in contact resistance hardly occurs. However, since the load torque at the time of driving increases due to the frictional resistance on the contact surfaces of the movable contact and the fixed contact, a large driving force is required. For this reason, the energy of the energy storage spring used as a drive source for the switching switch must be increased, so that the energy storage mechanism becomes large, and the damper that alleviates the impact due to the surplus energy immediately after the switching is completed. Will become large.

  However, in the on-load tap switching device according to the embodiment of the present invention, the contact method of the movable contact 81 and the fixed contact 63 is not a sliding type centering on the output shaft 58 but a butt type contact driven by a cam. For this reason, since the load torque due to the frictional resistance of the movable contact 81 and the fixed contact 63 can be reduced, the energy required for switching can be reduced, and the energy storage mechanism 57 can be downsized.

  Further, while the contact method of the movable contact 81 and the fixed contact 63 is a butt-type contact, in the process in which the movable contact 81 contacts the fixed contact 63, the contact surface slides while moving slightly. That is, the movable contact 81 performs insertion into the fixed contact 63 and opening from the fixed contact 63 while performing circular movement. With such a configuration, the movable contact 81 and the fixed contact 63 come into contact with each other while slightly sliding. As a result, the energized contact surfaces of the movable contact 81 and the fixed contact 63 are polished to each other, and a film such as an oxide film is removed, thereby preventing contact overheating due to increased contact resistance.

  Further, since the sliding distance is small, the amount of contact wear due to sliding friction is small, and the load torque can be kept low, so that the energy stored as the drive source of the auxiliary contact unit 73 of the switching switch 22 can be reduced. Therefore, the energy storage mechanism 57 can be reduced in size.

  FIGS. 5A to 5I are diagrams illustrating an operation when the switching switch according to the embodiment of the present invention switches the contact. FIG. 6 is a diagram illustrating an operation sequence of each unit in the switching switch. The timings (a) to (i) shown in FIG. 6 correspond to FIGS. 5 (a) to (i), respectively. In FIG. 5, TP1 and TP2 correspond to the odd-numbered side tap and the even-numbered side tap of the coil 11, respectively.

  First, the operation when the on-load tap switching device according to the embodiment of the present invention performs tap switching will be described with reference to FIG.

  The tap selector 21 switches from the state in which only the tap TP1 is selected to the state in which the tap TP1 and the tap TP2 are selected, and only the tap TP2 from the state in which the tap TP1 and the tap TP2 are selected. Switch to the state where is selected. FIG. 5 shows a state where the tap selector 21 selects the tap TP1 and the tap TP2.

  The switching switch 22 has a neutral point N between the tap TP1 and the coil 11 via the fixed contact 63OD before the tap selector 21 switches from the selection state of the taps TP1 and TP2 to the selection state of only the tap TP2. To the electrical connection (FIG. 5 (i)) between the neutral point N of the coil 11 and the tap TP2 via the fixed contact 63EV. Here, the switching switch 22 is in a bridge state (FIG. 5G) in which the neutral point N of the coil 11 and both the tap TP1 and the tap TP2 are electrically connected via the current limiting resistor R. As a result, the load current path is switched so that the electrical connection via the vacuum valve between at least one of the tap TP1 and the tap TP2 and the neutral point N of the coil 11 is not interrupted.

  Next, the operation when the switching switch according to the embodiment of the present invention switches contacts will be described in detail.

  When the cam roller 82 attached to the tip of the drive arm 83 rolls or slides as the output shaft 58 rotates, the movable contact 81 rolls or slides while contacting the fixed contact 63. 81 and the fixed contact 63 are in an energized state. Further, when the movable contact 81 moves in a non-contact state with the fixed contact 63, the movable contact 81 and the fixed contact 63 are not energized.

  The movable contact 81 reciprocally moves between the odd-numbered fixed contact 63OD and the even-numbered fixed contact 63ED, thereby switching between the odd-numbered tap T1 and the even-numbered tap T2.

  More specifically, referring to FIG. 5 (a), the vacuum valve VSM includes a first end electrically connected to the movable contact 81 and an output side terminal of the coil 11 shown in FIG. And a second end electrically connected to the first end. The vacuum valve VSR has a first end electrically connected to the first end of the current limiting resistor R and a second end electrically connected to the neutral point N of the coil 11 shown in FIG.

  Current limiting resistor R has a first end electrically connected to the first end of vacuum valve VSR and a second end electrically connected to fixed contact 63OD. The fixed contact 63OD and the current limiting resistor R are electrically connected to the tap TP1 when the tap selector 21 selects the tap TP1. The fixed contact 63EV is electrically connected to the tap TP2 when the tap selector 21 selects the tap TP2.

  5A and 6, first, the movable contact 81 is in contact with the fixed contact 63OD, the vacuum valve VSR is open, and the vacuum valve VSM is closed.

  Next, referring to FIG. 5B and FIG. 6, the vacuum valve VSR is closed. Further, the drive arm 83 starts rotating in the direction from the fixed contact 63OD to the fixed contact 63EV. At this time, since the cam roller 82 at the tip of the drive arm 83 is located in the idling section described above, the movable contact 81 does not rotate.

  Next, referring to FIG. 5C and FIG. 6, the vacuum valve VSM is opened. In addition, the drive arm 83 continues to rotate in the direction from the fixed contact 63OD to the fixed contact 63EV. At this time, since the cam roller 82 at the tip of the drive arm 83 is located in the idling section described above, the movable contact 81 does not rotate.

  5 (d) and 5 (e) and FIG. 6, next, the cam roller 82 at the tip of the drive arm 83 exits the above-mentioned idling section and reaches the engagement groove 86 of the movable contact 81, and the engagement groove Pass over 86. Then, since the movable contact 81 switches its position, the fixed contact 63OD is opened, and the movable contact 81 is not in contact with the fixed contacts 63OD and 63EV.

  Referring to FIG. 5 (f) and FIG. 6, next, fixed contact 63EV is closed, that is, movable contact 81 is in contact with fixed contact 63EV.

  Next, referring to FIG. 5G and FIG. 6, the vacuum valve VSM is closed. At this time, since the cam roller 82 at the tip of the drive arm 83 is located in the idling section described above, the movable contact 81 does not rotate.

  Next, referring to FIG. 5 (h) and FIG. 6, the vacuum valve VSR is opened. At this time, since the cam roller 82 at the tip of the drive arm 83 is located in the idling section described above, the movable contact 81 does not rotate.

  5 (i) and 6, movable contact 81 is in contact with fixed contact 63EV, vacuum valve VSR is open, and vacuum valve VSM is closed.

  By such an operation, in FIG. 6, the period T from when the vacuum valves VSM and VSR are opened to complete energization is obtained from the rotation range α of the drive arm 83, and the fixed contacts 63OD and 63EV are obtained. , That is, the rotation angle θ can be obtained.

  Further, it is movable in a period necessary for opening the vacuum valve VSM, that is, a period from the timing when the vacuum valve VSM starts opening (FIG. 5B) to the time after a predetermined time (FIG. 5D). The contact 81 can be prevented from opening. That is, from the state where the vacuum valve VSM is closed (FIG. 5A) to the state where the energization is completed by opening the vacuum valve VSM (FIG. 5C), the contact of the movable contact 81 is performed. The tip is switched from the fixed contact 63OD to the fixed contact 63EV (FIGS. 5D to 5F). Thereby, generation | occurrence | production of the arc in the movable contact 81 and the fixed contact 63 at the time of switching the connecting point of the movable contact 81 can be prevented.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  DESCRIPTION OF SYMBOLS 10 Transformer, 11 Coil, 13 Transformer tank, 15 Insulating oil, 21 Tap selector, 22 Switching switch, 23 Switching switch container, 24 Driving device, 25 Driving force transmission part, 27 Electric operation mechanism part, 53 Gear , 55 drive shaft, 57 energy storage mechanism, 58 output shaft, 60 contacts, 61, 61a, 61b, 61c, 61d movable contact, 63, 63OD, 63ODU, 63ODV, 63ODW, 63EV, 63EVU, 63EVV, 63EVW fixed contact, 64 Spring, 65 connection, 71 central shaft, 72 bell crank, 73 auxiliary contact unit, 74 vacuum valve unit, 81, 81U, 81V, 81W movable contact, 82 cam roller, 83 drive arm, 85 rotating shaft, 88OD, 88EV arm , 89 Output member, 91 Auxiliary contact, 101 Tap switching at load Location, TP1, TP2 tap, S1, S3 inactive regions, S2 operating region, VSM, VSMU, VSMV, VSMW, VSR, VSRU, VSRV, VSRW vacuum valve.

Claims (8)

A tap switching device for switching a turns ratio of a transformer including a coil,
A housing filled with an insulating medium;
A tap selector that is provided outside the housing and selects at least one tap from a plurality of taps provided at a plurality of positions in a coil included in the transformer;
A contact switch provided in the housing and including a contact point through which a load current flows between the tap selected by the tap selector and a predetermined node; and a switching switch for opening and closing the contact point,
The switching switch is
An output member that rotates about a predetermined axis;
A plurality of fixed contacts each electrically connected to the different taps via the tap selector;
A movable contact that operates as the output member rotates and selectively connects to the plurality of fixed contacts;
A current limiting resistor connected to any of the plurality of fixed contacts;
A first vacuum valve connected between the predetermined node and the current limiting resistor;
A second vacuum valve connected between the predetermined node and the movable contact;
The movable contact, the plurality of fixed contacts, and the first vacuum valve and the second vacuum valve are provided so as to intersect with the same plane orthogonal to the predetermined axis,
The movable contact is a tap switching device provided inside the plurality of fixed contacts and the first vacuum valve and the second vacuum valve in a radial direction about the predetermined axis. Each of the plurality of fixed contacts has a connection portion for contacting the movable contact,
2. The tap switching device according to claim 1, wherein each of the connection portions is provided on the inner side of the first vacuum valve and the second vacuum valve in a radial direction about the predetermined axis. The transformer includes a multi-phase coil;
The movable contact, the plurality of fixed contacts, the current limiting resistor, the first vacuum valve and the second vacuum valve are provided for each phase,
The first vacuum valve and the second vacuum valve of the plurality of phases are provided at intervals from each other in a circumferential direction around the predetermined axis,
The movable contacts and the fixed contacts of the plurality of phases, the first vacuum valve and the second vacuum valve are provided so as to intersect with the same plane orthogonal to the predetermined axis,
3. The tap switching device according to claim 1, wherein the movable contacts of the plurality of phases are provided inside the first vacuum valve and the second vacuum valve of the plurality of phases. Each of the multiple-phase fixed contacts has a connection for contacting the movable contact,
4. The tap switching device according to claim 3, wherein each of the connection portions is provided inside the first vacuum valve and the second vacuum valve of the plurality of phases. The plurality of fixed contacts include a first fixed contact and a second fixed contact that are provided adjacent to each other in a circumferential direction around the predetermined axis and are selectively connected to the movable contact,
The output member has a cam roller that reciprocates along a circumferential direction centering on the predetermined axis while rolling with respect to the movable contact with the rotational movement thereof,
The movable contact has a first arm part and a second arm part provided to face the first fixed contact and the second fixed contact, respectively, between the first arm part and the second arm part. A first position at which the first arm portion comes into contact with the first fixed contact and the second arm portion is separated from the second fixed contact upon receiving a reciprocating movement of the cam roller. The first arm portion is separated from the first fixed contact, and the second arm portion swings between a second position where the second arm portion contacts the second fixed contact. Tap changer. The movable contact extends along a circumferential direction centering on the predetermined axis, and contacts the cam roller when the cam roller is positioned at the moving end on the first position side and the second position side, respectively. A cam surface having a first end and a second end is formed;
The cam surface is formed across a predetermined angle from the first end and the second end in a circumferential direction centered on the predetermined axis, and the movable contact is non-moving while the cam roller contacts. An operation that is formed between the first non-operating region and the second non-operating region to be operated, and between the first non-operating region and the second non-operating region, and the movable contact is operated while the cam roller contacts. The tap switching device according to claim 5, wherein the tap switching device is divided into regions.   The tap switching device according to claim 6, wherein the operating region is formed in a groove shape that is recessed in the cam surface than the first non-operating region and the second non-operating region.   The tap according to claim 6, wherein a distance between the predetermined shaft and the rotation center of the cam roller is larger than a distance between the rotation center of the cam roller and the swing center of the movable contact when the cam roller contacts the operation region. Switching device.

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