JP2001118475A - Vacuum valve-type switching apparatus for making tapping when loaded - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vacuum valve-type switching apparatus for making a tapping when loaded whose size is considerably reduced by reducing both a resistor and energy storage device. SOLUTION: A drive shaft 2 is disconnected from or reversely connected to a power by means of the energy storage device. The rotation of the drive shaft drives three vacuum valve control mechanisms 7 per one phase. The sum of the torques delivered by all the vacuum valve control mechanisms accelerates the rotational speed of the drive shaft. A control cam 8 is fixedly attached to the drive shaft while an arm 9 with a roller 11 is arranged in the outside of the control cam. The control spring 10 pushes the arm to continuously contact the roller with the control cam, so that the loading torque transferred from the control spring through the roller to the control cam to the drive shaft smoothes the sum of the torques, reversed from the positive.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vacuum valve type switching switch of a tap changer under load which is a part of a transformer or a voltage regulator. More specifically, the present invention relates to a vacuum valve type switching switch of a one-resistance type, single-circuit stepping type on-load tap changer.

[0002]

2. Description of the Related Art In a vacuum valve type switching switch of a tap changer under load, a one-resistance type, single-circuit stepping-type switching switch is equivalent to U, V, and W as shown in FIGS. The taps are switched by sequentially opening and closing three vacuum valves A, B, and C.

The opening / closing operation of the three vacuum valves A, B, and C of each phase (U phase in the drawing) will be described in detail. Taps are switched from an odd number side to an even number side (hereinafter abbreviated as odd to even). At the time of switching, the vacuum valve A on the odd side is closed and the vacuum valve B is closed from open, then the vacuum valve A on the odd side is closed from open, and finally, the vacuum valve C on the even side is closed. Open to closed. Further, when switching from even to odd, the vacuum valve C on the even-numbered side is changed from closed to open while the vacuum valve B is closed, and then the vacuum valve A on the odd-numbered side is changed from open to closed. The vacuum valve B changes from closed to open. Therefore,
The opening and closing sequence was asymmetrical.

As shown in FIGS. 8 and 9, the structure of the vacuum valve type switching switch of the conventional on-load tap switching device which performs the above-described opening and closing operation is such that when the tap is switched, the output of the energy storage mechanism is changed. By rapidly rotating the shaft 91, the drive shaft 93 to which the three drive cams 92 are fixed is rotated forward or backward by a predetermined angle, and the drive valve 92 operates the vacuum valve operating mechanism 94.

A pressing force of a torsion coil spring 95 of a vacuum valve operating mechanism is constantly applied to each drive cam from a roller, and this pressing force is caused by forward or reverse rotation of the drive shaft.
The load torque increases or decreases the rotation speed of the drive shaft. That is, when the vacuum valve changes from open to closed, the roller climbs the inclined portion of the drive cam against the pressing force of the torsion coil spring, so that the drive shaft is decelerated. On the other hand, during the period from the closed state to the open state, the roller is torsionally moved down the inclined portion of the cam by using the pressing force of the coil spring, and is accelerated.

By the way, when the tap is switched, a current temporarily flows through the resistor R connected in series to the vacuum valve B. Therefore, the resistor R needs a capacity corresponding to the energization time t so that the resistor R does not melt due to a rise in temperature due to energization. To reduce the resistance of the resistor, the energization time t
Can be shortened, but the energization time t is reduced by the vacuum valves A and C
Since the minimum time required for the arc to completely extinguish is required, the arc cannot be shortened more than the extinguishing time.

[0007] The conventional vacuum valve type switching switch of the on-load tap changer has an extremely large difference in the energizing time t to the resistor R between switching from odd to even and switching from even to odd. was there. This is because, when switching from odd to even as shown in FIG. 4A, load torques of deceleration, acceleration, and deceleration are sequentially applied to the drive shaft from the three vacuum valve operating mechanisms. t is the time required from the acceleration of the decelerated drive shaft to the end of the deceleration.
On the other hand, when switching from even to odd, the drive shaft accelerates,
Since load torques for deceleration and acceleration are sequentially applied, the energization time t in this case is a time required after the drive shaft is accelerated until deceleration ends. As a result, there is a difference in the rotation speed of the drive shaft at the start of the energization time.

Therefore, in order to ensure the arc extinguishing time, it is necessary to match the shorter energizing time, that is, the energizing time t in the case of switching from odd to even in the drawing, to the extinguishing time. Energization time t when switching to odd
Became much longer than the extinction time. To prevent fusing, it is necessary to set the capacity of the resistor in accordance with the longer energization time t.
This was a factor that made it impossible to downsize the resistor.

Therefore, the energizing time t is made equal and the resistor R
As a conventional means for reducing the size of the opening / closing sequence, as shown in FIG. 7, it has been considered that the opening / closing sequence is made symmetrical so that the vacuum valve B is closed, opened and closed when the tap is switched. However, in this case, there is a disadvantage that the opening and closing operations of the vacuum valve B increase and the mechanical life is reduced by half. Further, according to the above-described method, the peak value of the load torque cannot be reduced, so that the energy storage mechanism cannot be downsized.

[00010]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to reduce the size of a resistor and an energy storage mechanism while maintaining the mechanical life of a vacuum valve. Accordingly, an object of the present invention is to provide a vacuum valve type switching switch of a load tap changer which can be significantly reduced in size as a whole.

[00011]

According to the present invention, a drive shaft is rotated forward or backward by an energy storage mechanism, and three vacuum valve operating mechanisms are operated per phase by rotation of the drive shaft. In a vacuum valve type switching switch of a load tap changer in which the combined torque transmitted from the mechanism accelerates or decelerates the rotation speed of the drive shaft, a control cam is fixed to the drive shaft and an arm having rollers is provided outside the control cam. The roller is always in contact with the control cam by pushing the arm with the control spring, and the load torque of the control spring transmitted from the roller to the drive shaft via the control cam is a smoothed version of the above-described combined torque, and the sign is reversed. There is a feature.

The drive shaft may be eccentric with respect to the output shaft of the energy storage mechanism, or may be arranged on the same straight line as the axis of the output shaft. In the former case, the drive shaft and the output shaft are connected by a connecting rod, and used to change the rotation angle of the output shaft to a required rotation angle of the drive shaft. In the latter case, the drive shaft and the output shaft are directly connected, or the drive shaft and the output shaft are formed by the same shaft.

[0013] Three vacuum valve operating mechanisms per phase means a one-resistance, single-circuit incremental system. In Japan, a three-phase three-wire power transmission system is usually employed, and thus the total number of vacuum valve operating mechanisms used in this case is nine.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A vacuum valve switching switch of a tap changer under load according to the present invention will be described with reference to FIGS. As shown in FIG. 3, the output shaft 1 of the energy storage mechanism (not shown)
, The drive shaft 2 is eccentrically disposed, and the first series rod 3 is fixed to the end of the output shaft 1 and the second connecting rod 4 is fixed to the end of the drive shaft 2. The second connecting rod 4 is connected by a connecting pin 5 to make the rotation angle of the drive shaft 2 larger than that of the output shaft 1, and three drive cams 6 are fixed to the drive shaft 1 at intervals. As shown in FIG. 2, three vacuum valve operating mechanisms 7 are arranged at intervals in the outer peripheral direction of the driving cam 6 for each driving cam 6. In FIG. 1, three vacuum valve operating mechanisms 7 are arranged in parallel in the axial direction of the drive shaft 2, but these are for the U phase, and those for the V and W phases are omitted for convenience. . Further, a control cam 8 is fixed to the second connecting rod 4, the arm 9 is swingably supported outside the control cam 8, and a control spring 10 is arranged outside the arm 9,
By pushing the swinging tip of the arm 9 by the control spring 10, the roller 11 provided at the tip of the arm 9 is always in contact with the control cam 8.

According to the present invention described above, the drive shaft 2 is rotated by an angle α by forward or reverse rotation of the output shaft 1, and the rotational motion of the drive shaft 2 is changed to the swinging motion of the vacuum valve operating mechanism 7 by the drive cam 6. The swing movement of the vacuum valve operating mechanism 7 is changed to the opening and closing movement of the vacuum valve 12. In addition, the rotational movement of the drive shaft 2 causes nine vacuum valve operating mechanisms 7 in all three phases.
And the load torque from the control spring 10 are transmitted to the drive shaft 2, and the load torque cancels out most of the resultant torque.

The structure in which the roller 11 is always in contact with the control cam 8 will be described in detail below. The first and second support pins 13 and 14 protrude outward from the control cam 8 at an interval inside and outside the frame F, and are held by the outer second support pins 14 through the cylindrical portion of the control spring 10. The arm 9 is swingably supported by the support pin 13, one end of the control spring 10 is hooked on a first locking pin 15 protruding from the frame F, and the other end is protruded from the tip of the arm 9. Pin 1
6 and the control spring 10 is
Is held in the open state, and the tip of the arm 9 is
Side so that the roller 11 is always in contact with the control cam 8.

Each vacuum valve operating mechanism 7 serves to open and close the vacuum valve 12 by changing the rotational movement of the driving cam 6 into a linear reciprocating movement of the movable electrode rod 17 of the vacuum valve 12. More specifically, the rotational movement of the drive cam 6 is
The swing motion of the lever 18 is changed to the swing motion of the movable electrode bar 17. The structure is as usual, and the third support pin 19 protruding from the frame F swingably supports the central portion of the lever 18, and the torsion coil spring 20 is arranged along the side surface of the lever 18. One end of the torsion coil spring 20 A third locking pin 21 whose part projects from the lever 18 itself
A fourth locking pin 22 having the other end protruding from the frame F.
To hold the torsion coil spring 20 in a state of holding the force to open it, and to bring the roller 23 at one end of the lever 18 into contact with the driving cam 6 at all times.
A case 25 having a contact pressure supply spring 24 built in at the other end of the case 8
Are connected by a fifth locking pin 26, and an insulating bar 27 extending continuously from the movable electrode bar 17 is fixed to the case 25.

The procedure for opening and closing the three vacuum valves A, B, and C for each phase is the same as that described in the section of the prior art, so that the description is omitted. As shown in
With the rotation of the drive shaft 2, the load torque of the torsion coil spring 20 is applied from the three vacuum valve operating mechanisms 7 of each phase to the drive shaft 2.
To accelerate or decelerate the rotation speed of the drive shaft 2. In order to keep the rotational speed of the drive shaft 2 as constant as possible, the opening / closing timings of the vacuum valves of the U, V, and W phases are shifted to offset the load torques transmitted to the drive shaft 2 as much as possible. As shown, the peak value of the combined torque of the nine vacuum valve operating mechanisms 7 is suppressed as much as possible. The resultant torque is a curve having a large amplitude, and it is extremely difficult to realize the same load torque as the resultant torque with one cam. Therefore, the outline of the curve is grasped and the smoothing torque is obtained as shown in FIG. In addition, as shown in FIG. 4F, the design and control of the contour of the control cam 8 are performed so that the reverse of the smoothing torque is applied to the drive shaft 2 as the load torque of the control spring 10. The spring 10 is selected. In this way, the peak value of the load torque finally given to the drive shaft 2 is drastically reduced by the load torque transmitted from one control cam 8.

The present invention is not limited to the above embodiment. For example, the control cam 8 may be directly fixed to the drive shaft 2 without being fixed to the second connecting rod 4. Also,
The arm 9 is not limited to the swinging structure, but may be a structure that linearly reciprocates along its longitudinal direction. However, in the case of a parallel configuration in which the tip of the arm 9 is swung and the control spring 10 follows the arm 9, a compact shape is obtained.

[0020]

The vacuum valve switching switch of the tap changer under load according to the present invention is a control spring that smoothes the combined torque and reverses the polarity in addition to the combined torque of three vacuum valve operating mechanisms per phase. Is applied to the drive shaft from the control cam, so that the resultant torque is almost negated,
Of course, the peak value is much smaller than before,
The load torque applied to the drive shaft as a whole is only slightly moved based on 0, and as a result, the energy storage mechanism can be downsized. Also, the load torque given as a whole is 0
The tap is switched from the odd side to the even side, and when the tap is switched from the even side to the odd side, the rotation speed of the drive shaft is made uniform, and the The energization time is made uniform, and the energization time can be set as close as possible to the arc extinction time. As a result, the resistor can be made smaller than before. Therefore, by reducing the size of the energy storage mechanism and the resistor, it is possible to significantly reduce the size as a whole such that the increase in the number of components such as the control spring and the control cam does not matter at all.

[Brief description of the drawings]

FIG. 1 is a schematic front view of a vacuum valve type switching switch of a tap changer under load of the present invention, wherein one of three vacuum valves of each of U, V, and W phases is operated by one driving cam. In addition, it shows a state in which the vacuum valve is closed.

FIG. 2 is a schematic front view of a vacuum valve type switching switch of the on-load tap changer of the present invention, showing a state in which a vacuum valve is opened.

FIG. 3 is a schematic side view of a vacuum valve switching switch of the on-load tap changer of the present invention, showing a relationship between three vacuum valve operating mechanisms for one phase and a drive shaft.

FIGS. 4 (a), (b), (c), (d), (e), and (f) are load torque diagrams of the drive shaft, and FIG. The graph shows the W-phase load torque, composite torque, smoothing torque, and load torque from the control spring.

FIG. 5 is a circuit diagram of one phase of a vacuum valve type switching switch of the on-load tap changer.

FIG. 6 is an opening / closing sequence for one phase of a vacuum valve type switching switch of a tap changer under load.

FIG. 7 is an opening / closing sequence for one phase of a conventional vacuum valve switching switch of a tap changer under load.

FIG. 8 is a schematic side view showing a conventional vacuum valve type switching switch of the on-load tap changer.

FIG. 9 is a schematic front view of a conventional vacuum valve type switching switch of a tap changer under load.

[Explanation of symbols]

 2 Drive shaft 7 Vacuum valve operating mechanism 8 Control cam 9 Arm 10 Control spring 11 Roller

Claims (1)

[Claims] The drive shaft (2) is rotated forward or backward by an energy storage mechanism, and three vacuum valve operating mechanisms (7) are operated per phase by rotation of the drive shaft (2), and all vacuum valves are operated. A control cam (8) is fixed to the drive shaft (2) in a vacuum valve type switching switch of a tap changer under load in which the combined torque transmitted from the operation mechanism (7) accelerates or decelerates the rotation speed of the drive shaft (2). At the same time, the arm (9) having the roller (11) is arranged outside the control cam (8), and the arm (9) is pushed in by the control spring (10) to always move the roller (11) to the control cam (8). Contact,
Drive shaft (2) from roller (11) via control cam (8)
Wherein the load torque of the control spring (10) transmitted to the load tap is a value obtained by smoothing the composite torque and reversing the sign.