JPS6348373B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention relates to an improvement in a switching switch constituting an on-load tap changer.

Technical background of the invention The on-load tap changer (hereinafter referred to as LTC) is
It usually consists of a tap selector and a switching switch.
A tap selector that selects taps in a no-voltage state is
The contacts cannot be damaged by arcing, but
The switching switch, which works in conjunction with the tap selector to transfer the circuit from the original tap to the next tap selected by the tap selector, forces the load current and the circulating current that inevitably occurs when transferring the circuit. It is necessary to open and close the contacts periodically, and especially when the circuit is open, an arc is generated between the contacts, causing serious damage to the contacts. For this reason, switching switches require frequent maintenance and inspection.

As a method that does not require such frequent maintenance, a method is known in which a long-life vacuum circuit breaker (hereinafter referred to as VCB) is applied to the contacts of the switching switch.

FIG. 1 shows a typical conventional one-resistance, three-valve type LTC circuit diagram using such a VCB.

In the figure, 1 is a tap winding, T ₁ , T ₂ , T ₃ are taps, 2 and 3 are tap selectors, 4 is a VCB 5,
6, 7 and a current limiting resistor 8.

When tap selector 2 selects tap _T1 ,
When VCB5 is closed, load current flows through tap winding 1, tap _T1 , tap selector 2, and VCB5. When switching from this state to Tap T ₂ ,
First, VCB6 is closed, VCB5 is opened, and the load current flows through current limiting resistor 8 and VCB6. next,
After closing VCB7, open VCB6. In this way, the load current is switched from tap T ₁ to a path through tap T ₂ and VCB7.

By the way, this switching order must always be accurately switched within a short period of several seconds. During this switching process, a circulating current flows across both the taps _T1 and _T2 , but this circulating current is suppressed through the short-time rated current limiting resistor 8.

Next, VCB5 in such a switching process,
The opening/closing mechanism of one of 6 and 7 will be explained with reference to FIG. VCB5, 6, 7 are fixed contacts 1
1, an outer wall 12, a bellows 13 attached to the outer wall 12, and a movable contact 14 further attached to the bellows 13. Lead wires 15 and 16 are connected to the fixed contact 11 and the movable contact 14. In addition, 17 is a cam, 18 is a compression spring 19, 20
21 is the opening/closing lever 18 inserted.
A bracket 22 supporting the opening/closing lever 18 is a roller attached to the opening/closing lever 18 via a pin 23. In this case, the compression spring 19 inserted between the opening/closing lever 18 and the bracket 21 supporting it
This is to increase the breaking speed of the movable contact 14 so that it is easier to break the load current and circulating current when the contact opens.The compression spring 20 applies contact force to the movable contact 14, and also Increase the amount of wipe at the time,
And if the movable contact 14 is worn out, the movable contact 14
This is to compensate for the above-mentioned wear and tear. The opening/closing of the movable contact 14 is performed by rotating the cam 17 to move in and out the opening/closing lever 18 into which compression springs 19 and 20 are inserted, and the roller 22 attached thereto.

In Fig. 3, a planar cam 17' having an axis parallel to the axial direction of the VCB is arranged in place of the cam 17 in Fig. 2, and the same components as in Fig. 2 are given the same numbers. The explanation will be omitted. In this case as well, the rotation of the cam 17' opens and closes the movable contact 14 of the VCB in the same manner as in FIG.

Problems with the Background Art A drawback of the opening/closing mechanism shown in FIG. 2 is that it is difficult to create a compact design when the number of VCBs installed increases. In other words, when constructing a three-phase opening/closing mechanism using the one-resistance, three-valve system as shown in Figure 1, the
It would be necessary to have three times as many VCB opening/closing mechanisms, or 9 sets, arranged radially around the camshaft, making the diameter of the cam etc. extremely large. Therefore, it is very difficult to arrange them compactly. Further, the disadvantage of the opening/closing mechanism shown in FIG. 3 is that when a large number of VCBs are arranged around the axis of the cam 17', the dimensions of the cam 17' become very large.
It is too heavy and unsuitable for instantaneous operation.

OBJECTS OF THE INVENTION It is an object of the present invention to provide a VCB opening/closing mechanism that eliminates the above drawbacks and can be made compact even when the number of pulses increases.

SUMMARY OF THE INVENTION In order to achieve this object, the present invention provides a rotary shaft that is fixed approximately in the middle of a rotating shaft that is pivotally supported in the vertical direction;
and a grooved cam in which two grooves are formed on the upper and lower sides of the outer peripheral surface, and a plurality of grooves in the vertical direction of this grooved cam, and
A plurality of VCBs arranged concentrically around the grooved cam, and a plurality of vertical drive drives provided corresponding to these VCBs and each having a roller at one end that fits into the upper and lower grooves of the grooved cam, respectively. It is characterized by comprising a shaft and a plurality of levers having a fulcrum between each of the drive shafts and the movable electrode of each VCB and transmitting the movement of the drive shaft to the movable electrode of the VCB.

Embodiments of the Invention The present invention will be described below with reference to embodiments shown in the drawings.

FIG. 4 shows a VCB opening/closing mechanism according to an embodiment of the present invention, and in the figure, the same reference numerals as in FIGS. 2 and 3 indicate the same or corresponding parts.

In this embodiment, the pin 2 is attached to the opening/closing lever 18.
5, a rod 27 connected to an insulating shaft 26 is provided parallel to the axial direction of the opening/closing lever 18, and a roller 29 that engages with a grooved cam 28 is attached to the tip of the insulating shaft 26. Further, a pin 30 is provided on this rod 27, and a pin 30 is provided on the bracket 21 between this pin 30 and a pin 25 provided on the opening/closing lever 18.
An operating lever 3 mounted so as to be swingable with reference to 1 as a fulcrum.
It is characterized by the points connected by 2.

In the above configuration, when the grooved cam 28 rotates around the shaft 33, the roller 2 fitted to the cam 28
9 moves in the vertical direction according to the shape of the groove. As a result, the insulating shaft 26 to which the roller 29 is attached moves in the vertical direction, and this movement is transmitted to the movable contact 14 of the VCB via the rod 27, the operating lever 32, and the opening/closing lever 18, thereby opening and closing the VCB.

Therefore, according to the above configuration, the shaft 33 of the cam 28
The center of the VCB can be aligned with the axis of the switching switch, and a large number of VCBs can be arranged radially around the axis 33. Further, since the dimensions of the cam 28 can be made appropriately, an advantage can be obtained that its weight can be reduced.

5, 6, and 7 show other embodiments of the present invention, in which FIG. 5 is a front sectional view of the VCB opening/closing mechanism, FIG. 6 is a view taken in the direction of arrow A in FIG. FIG. 7 is a sectional view taken along line BB in FIG. 5. In addition, in Fig. 5, the opening/closing mechanism is configured vertically symmetrically, so
Only one of them will be explained, and the explanation of the other will be omitted.

Throughout each figure, 51 and 52 are supports that are tightened by studs 54 and nuts 55 with a constant dimension maintained between them by a spacing tube 53 inserted between them, and supported by support members (not shown). It is installed in the switching switch room of the on-load tap changer. A shaft 56 is connected to a drive source (not shown) and rotates, and is rotatably attached to the support 52 via a bearing 77.
A grooved cam 58 is fixed to the shaft 56 and rotates together with the shaft 56. The roller 59 is the grooved cam 5
8 rotates, it is guided along the groove and moves up and down. A roller 59 is rotatably supported at one end of the guide 60, and the other end is guided by a guide pin 62 fixed to the support 51 by a pin 61. This guide pin 62 is connected to the roller 59
The grooved cam 58 is provided to prevent lateral vibration and horizontal component force that occur when the grooved cam 58 is guided along the groove, and to ensure vertical movement. One end of the insulating shaft 63 is fixed to the guide 60 and the other end to the operating rod 64 via a pin 65. The operating rod 64 has a connecting pin 69 that connects to an operating lever 68 that is connected to an opening/closing lever 66 via a pin 67. The lever 68 is a compression spring 70
The bracket 7 engages with the opening/closing lever 66 via
It is rotatably attached to the fixed pin 72 of No. 1, and transmits vertical movement from the guide 60 to the opening/closing lever 66.
The opening/closing lever 66 has a built-in spring 73.
The spring 73 has one end attached to the opening/closing lever 66 and the other end attached to the opening/closing lever 66.
It contacts the movable electrode 75 of the VCB 74 and applies the necessary contact load to the fixed and movable contacts of the vacuum valve. Reference numeral 76 is a lead line for forming an electrode circuit. Fixed electrode 77 is fixed to terminal 78.

With the above configuration, when the shaft 56 rotates, the grooved cam 58 rotates. When the grooved cam 58 rotates, the roller 59 fitted in a groove provided on the outer peripheral surface of the grooved cam 58 moves in the vertical direction according to the shape of the groove. As a result, the guide 60 to which the roller 59 is attached moves vertically, and this movement causes the insulating shaft 6
3. Via the operating lever 68 and opening/closing lever 66
The signal is transmitted to the movable electrode 75 of the VCB 74, and the VCB 74 is opened and closed. At this time, the roller 59 collides with the slope of the grooved cam 58 due to the high speed rotation of the grooved cam 58, and receives a repulsive force, but because it is fitted into the groove of the grooved cam 58, it does not bounce back as much as in the case of a flat cam. There isn't.

In this way, by placing the VCB and its opening/closing mechanism on both the upper and lower surfaces of the cam, the fourth
Compared to what is shown in the figure, more VCBs can be arranged, which is more advantageous in making the opening/closing mechanism more compact.

Effects of the Invention As explained above, according to the switching switch of the on-load tap changer of the present invention, since the VCB is arranged in the vertical direction on a concentric circle, The diameter is small because the number of VCBs arranged concentrically in parallel can be reduced, and therefore the switching switch diameter can also be small. In addition, the VCB placed above and below
is opened and closed via a grooved cam with two grooves and an insulated drive shaft connected to a roller that moves up and down according to the movement of this cam, which has the advantage that the overall structure is extremely simple. is obtained.

[Brief explanation of the drawing]

Figure 1 is a conventional one-resistance, three-valve type LTC circuit diagram, Figure 2 is a schematic diagram showing an example of an opening/closing mechanism that opens and closes one VCB in Figure 1, and Figure 3 is another conventional opening/closing mechanism. 4 is a schematic diagram of an opening/closing mechanism according to an embodiment of the present invention, FIG. 5 is a front sectional view of an opening/closing mechanism showing another embodiment of the present invention, and FIG. View from arrow A, Figure 7 is B- in Figure 5.
It is a sectional view of B. 25, 30, 31, 61, 62, 65, 67,
69, 72... Pin, 26, 63... Insulated shaft, 2
7... Rod, 28,58... Groove cam, 29,5
9...Roller, 32, 68...Operation lever, 33
...shaft, 51, 52 ... support, 53 ... spacing tube, 54 ... stud, 55 ... nut, 56 ...
... Shaft, 57 ... Bearing, 60 ... Guide, 64 ... Operation rod, 66 ... Opening/closing lever,
70, 73...compression spring, 71...bracket,
74...VCB, 75...movable electrode, 76...lead wire, 77...fixed electrode, 78...terminal.

Claims (1)

[Claims] 1. A grooved cam that is fixed approximately in the middle of a rotating shaft that is pivotally supported in the vertical direction, and that has two grooves formed on the top and bottom of its outer peripheral surface, and a plurality of grooves that are formed in the vertical direction of this grooved cam. A plurality of vacuum shields and disconnectors arranged concentrically around the cam, and rollers provided at one end corresponding to the vacuum shields and disconnectors and fitted in the upper and lower grooves of the grooved cam, respectively. a plurality of vertically moving drive shafts, and a plurality of levers that have a fulcrum between each of these drive shafts and the movable electrode of each vacuum shield and disconnector, and transmit the movement of the drive shaft to the movable electrode of the vacuum shield and disconnector. A switching switch for an on-load tap switch, characterized by comprising: