JP2642727B2 - Circuit of vacuum switch type tap changer under load - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a circuit of a vacuum switch type tap changer under load.

[Conventional technology]

In recent years, substation facilities installed in densely populated areas such as underground shopping malls and high-rise buildings have been adopting devices using SF ₆ or the like in consideration of disaster prevention. No exception in the transformer, using a SF ₆ gas SF ₆ gas insulated transformers and SF
A non-combustible transformer using a mixture of ₆ gases and other media or a special medium has been adopted to promote non-combustibility. Accordingly, there is a demand for a non-combustible load tap changer for voltage adjustment which is built in and used in a transformer.

As a device therefor, there is a vacuum switch type load tap changer using a vacuum switch which aims at complete non-combustibility by preventing an arc from being emitted in the medium at the time of tap change.

By the way, this vacuum switch type tap changer at the time of load is not versatile, and the vacuum switch used for the current switching part is
Utilizes the high breaking performance of current in a high vacuum, and if the high vacuum is broken for any reason and the degree of vacuum is reduced, then the function of time or Passien's law representing the relationship between the degree of vacuum and the dielectric strength. As a result, the dielectric strength is significantly reduced, and the vacuum switch itself does not function. In other words, when the current is interrupted, the current cannot be interrupted, and the arc between the connections continues.Also, despite the contacts being open in the normal operation state, the inrush of a steep surge voltage may cause dielectric breakdown, In the worst case, these may lead to a short circuit between the taps of the transformer, and the large currents may cause each contact to overheat or melt the insulator, etc. The result is a fatal blow.

On the other hand, the vacuum leakage of the vacuum switch, which is the cause of this problem, is generally considered to be affected by the history of the number of times of switching, energizing time, voltage application time, etc., except for manufacturing defects such as defective welding of hermetic parts. . Therefore, even if it is inevitable that the number of times of switching should be a certain number of times as long as it is used for a tap changer, the factor that affects the vacuum leakage can be eliminated by reducing the load by reducing the energization time and the voltage application time. It is anticipated that attempts will be made to lower the probability of vacuum leakage of the vacuum switch at least.

As an example, the one shown in FIG. 7 has been proposed,
This type is generally used in JP-A-55-130117.

FIG. 7 shows a conventional example of a circuit of a vacuum switch type tap changer under load. In the figure, TW is a tap winding, TS ₁
And TS ₂ are tap selector for selecting taps of tap winding TW. 1 is a movable leading contact, 2 and 3 are fixed leading contacts connected to the tap selectors TS ₁ and TS ₂ respectively, 4 is a movable auxiliary contact, and 5 and 6 are tap selectors TS ₁ and TS. _Two
Are fixed auxiliary contacts which are respectively connected. Reference numeral 7 denotes a movable energizing contact, and reference numerals 8 and 9 denote fixed energizing contacts connected to the tap selectors TS ₁ and TS ₂ , respectively. N is the neutral point or the line end, being connected to the movable auxiliary contact 4 through the vacuum switch VS, further vacuum switch VS is a current limiting resistor R ₁₃ to be connected in series to the movable preceding turned contactor 1 It is connected to a resistance contact 10 for opening and closing. R ₁₁ and R ₁₂ are resistance elements inserted in series between the fixed auxiliary contact 5 and the tap selector TS ₁ and between the fixed auxiliary contact 6 and the tap selector TS ₂ , respectively. This circuit bypasses the circuit of the vacuum switch VS by the movable and fixed current-carrying contacts 7, 8, 9 in the normal operation state.

Meanwhile FIG. 7 shows a state of energization at tap selector TS ₁ side, current tap selector fixed conductive contact 8 from TS _1, via the movable conductive contact 7 neutral point or the line end N It is flowing to. Briefly explaining the switching operation from this state to the tap selector TS _2, first movable preceding turned contactor 1
Switches from the fixed preceding contact 2 to the same contact 3. In this state, the vacuum switch VS is closed. Next, the movable energizing contact 7 separates from the fixed energizing contact 8 and the resistive contact
10 closes. At this time, the load current is supplied via a tap selector TS ₁ -resistance element R ₁₁ -fixed auxiliary contact 5 -movable auxiliary contact 4 -vacuum switch VS-neutral point (or line end) N and a tap. Selector TS ₁ -Resistance element R ₁₁ -Fixed auxiliary contact 5-Movable auxiliary contact 4-Vacuum switch VS-Resistive contact 10-Current limiting resistor R ₁₃ -Movable advanced input contact 1-Fixed advanced input contact Through the circuit of the 3-tap selector TS ₂
A circulating current flows.

Next, the vacuum switch VS is opened, the movable auxiliary contact 4 is switched and connected to the fixed auxiliary contacts 5 to 6, and after the resistance contact 10 is opened, the movable electric contact 7 is connected to the fixed electric contact 9 , The switching operation is completed. This Conversely, if switching to TS ₁ side from tap selector TS ₂ side, after operating the movable preceding turned contactor 1 may be entirely performed in the reverse with the above operation.

More common to such a conventional example is a one-resistor, three-vacuum switch-type tap switch circuit at the time of a load as shown in FIG. Speaking of a time tap changer, this circuit is the first to appear. Similar to Figure 7 above in this circuit, by the 1st vacuum switch VS ₁ or VS ₂ provided movable conductive contact 7 that bypasses, tap selector current from tap winding TW in the normal operating condition Through the TS ₁ and the fixed energizing contact 8, the movable energizing contact 7 can be energized further to the neutral point or the line end N. The operation of tap change is well known, and the description is omitted. In the figure, VR ₁ is a second vacuum switch.

[Problems to be solved by the invention]

In the above-mentioned conventional technology, an energizing path that basically bypasses the vacuum switch is provided at the normal energizing position, and a vacuum leak of the vacuum switch is reduced by reducing the load on the vacuum switch except for current application and voltage application at the vacuum switch at the normal position. Is lowering the probability.

However, simply lowering the probability does not solve the fundamental problem. Further attention is paid to the circuit of FIG. 7 of the conventional example. If the vacuum switch VS leaks, the current cannot be cut off during switching, and the arc Is continued, an arc is generated between the fixed auxiliary contact 5 and the movable auxiliary contact 4 during the operation of the movable auxiliary contact 4, and when the arc continues to the next fixed auxiliary contact 6, the contact Is instantaneously melted, overheating and burning the nearby insulator, and the operation cannot be continued. Depending on the quality of the arc resistance such as the material of the contact, there may be a case where it can be interrupted to some extent, but if it is repeated, it will eventually become fatal.

In the circuit of FIG. 8, vacuum leakage occurs in the vacuum switch (the first vacuum switch VS ₂ in the state of FIG. 8; however, when the reverse circuit is energized, the first vacuum switch VS ₁ ). If a sharp surge voltage enters the circuit due to lightning or the like in a state where the proof strength is reduced, dielectric breakdown occurs between the contacts of the vacuum switch, and there is a possibility that the above-mentioned large accident may occur from a short circuit between taps.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and has as its object to provide a circuit of a vacuum switch type tap changer which can continue operation even if a vacuum switch causes vacuum leakage. .

[Means for solving the problem]

The object of the invention is to provide an auxiliary contact between each tap selector and each first vacuum switch which is capable of disconnecting all of the first and second vacuum switches from the power supply circuit. The movable auxiliary contact is disposed on the tap selector side, the movable auxiliary contact is disposed on the first vacuum switch side, and the pair of fixed auxiliary contacts are selectively connected to a neutral point or a line end. This is achieved by providing a main energizing contact.

[Action]

The above means is provided, and even if a vacuum leak occurs in one of the first and second vacuum switches, all vacuum switches including the vacuum switch leaked by the auxiliary contact are disconnected from the energizing circuit, The current can be passed through the movable main energizing contact so that the operation can be continued even if the vacuum switch causes a vacuum leak.

That is, each of the above-mentioned contacts operates as follows. First, the pair of auxiliary contacts are configured to be closed only at the time of tap switching, and all the vacuum switches are completely disconnected from the energizing circuit by opening after the tap switching. The movable main energizing contact is opened only when the tap is switched, and is in contact with one fixed auxiliary contact of the pair of auxiliary contacts at the end of the tap switching.

In this way, the current flows only through the movable main energizing contact, the vacuum switch is not inserted into the energizing circuit, and even if an abnormal surge voltage enters, it is not applied to the contacts of the vacuum switch. In addition, no dielectric breakdown occurs. Further, even if the arc cannot be interrupted during the switching due to the vacuum leak of the vacuum switch and the arc continues, the abnormality is detected by the detection circuit of another application, and the subsequent tap switching is locked. It is possible to continue the normal operation state in which the vacuum switch is disconnected from the energizing circuit as described above, and during that time, it is possible to take appropriate measures that do not hinder the operation of the equipment, such as planned shutdown of the transformer and promotion of regular inspection .

〔Example〕

Hereinafter, the present invention will be described based on the illustrated embodiments.
1 to 3 show one embodiment of the present invention. The same parts as those in the related art are denoted by the same reference numerals, and the description thereof will be omitted. The circuit of the vacuum switch type tap changer under load includes a tap winding TW, a pair of tap selectors TS ₁ and TS ₂ , and a first and a second vacuum connected in series to these tap selectors TS ₁ and TS ₂ , respectively. The switches VS ₁ , VS ₂ , VR ₁ , VR ₂ and the _{first of} the vacuum switches VS ₁ , VS ₂ , VR ₁ , VR _{2 on} the tap selectors TS ₁ , TS ₂ side
Resistors R ₁ and R ₂ connected in parallel to the _second vacuum switch VS ₁ and VS ₂
It has. Further, a neutral point or a line end N is formed at a connection portion connecting the ends of the second vacuum switches VR ₁ and VR ₂ opposite to the tap selectors TS ₁ and TS ₂ . The circuit of the vacuum switch type load tap changer constructed as described above, in the present embodiment, between each tap selector TS ₁ , TS ₂ and each first vacuum switch VS ₁ , VS _2. , These first and second vacuum switches VS ₁ , VS ₂ , VR ₁ , VR ₂
All with the energizing circuit provided disconnecting freely auxiliary contacts, the fixed auxiliary contact 5a of the auxiliary contacts, 5b the tap selector TS _1, TS ₂ side, the movable auxiliary contact element 4a, 4b of the first th A movable main energizing contact 11 is provided on the vacuum switch VS ₁ , VS ₂ side and selectively connects a pair of fixed auxiliary contacts 5 a and 5 b to a neutral point or a line end N. Such first and second vacuum by a switch _{VS 1, VS 2, VR 1} , VR
All vacuum switches, including vacuum switches leaked by the auxiliary contacts, even if vacuum leaks occur in any of ₂ )
VS ₁ , VS ₂ , VR ₁ , VR ₂ are disconnected from the energizing circuit and current can flow through the movable main energizing contact 11, and the vacuum switch VS ₁ , VS ₂ , VR ₁ , VR ₂ causes a vacuum leak. Operation can be continued even if the vacuum switches VS ₁ , VS ₂ , VR ₁ , and VR ₂ cause a vacuum leak. it can.

Namely, as shown in Figure 1, the first vacuum switch VS ₁ is connected in parallel with resistor R _1. And the second vacuum switch VR ₁ is the first vacuum switch V
S ₁ are connected in series. Similarly, the first vacuum switch VS ₂ is connected in parallel with the resistor R _2. The first second vacuum switch VR ₂ is connected 1st vacuum switch VS ₂ in series. The first second end of the vacuum switch VR ₁ and VR ₂ are connected together to form a neutral point or the line end N.

Meanwhile movable auxiliary contact 4a is provided on the tap selector TS ₁ side, the 1st vacuum switch VS ₁ and the second vacuum switch VR _1, is one which allows disconnecting from energizing circuit. The fixed auxiliary contact 5a is a tap selector TS ₁ side of contact of the movable auxiliary contact 4a. Meanwhile, the movable auxiliary contact element 4b likewise provided tap selector TS ₂ side, the 1st vacuum switch VS ₂ and the second vacuum switch VR _2, is one which allows disconnecting from energizing circuit. The fixed auxiliary contact 5b is a tap selector TS ₂ side of the contact of the movable auxiliary contact element 4b. The movable main contact 11 has one end selectively in contact with the fixed auxiliary contacts 5a and 5b of the movable auxiliary contacts 4a and 4b, and has the other end connected to a neutral point or the line end N.

State of the first figure shows a normal state where the tap selector TS ₁ is energized, the fixed auxiliary contact 5a and the movable main conductive contact 11 has contacts, the movable auxiliary contact 4a and 4b are opened because there, current passes through the tap selector TS ₁ from the tap winding TW, fixed auxiliary contact 5a, via the moving main conductive contact 11 is flowing through the neutral point or the line end N. This fully all vacuum state switch VS _1, VR _1, VR ₂ and VS ₂ is independent of the energizing circuit.

The tap is switched in this state, and the current is
Operation proceeds from TS ₁ to TS ₂ side is performed Te従Tsu the switching sequence shown in FIG. 3 (a) ~ (h) in the switching drawing and Figure 2 shows. As shown in FIG. 3, FIG.
Is the same state as in FIG. In the same figure (b), tap selector
At the same time as the TS ₂ moves to the next tap with no current, the pair of movable auxiliary contacts 4a and 4b close in synchronization with the movement, and the current is supplied to the movable main energizing contact 11 and the movable auxiliary contact 4a.
Diverted to a series circuit consisting of a first vacuum switch VS ₁ and the second vacuum switch VR ₁ Metropolitan passed through the. Next, in FIG. 3C, the movable main energizing contact 11 separates from the fixed auxiliary contact 5a in an arc-free state and moves to an intermediate position between the pair of fixed auxiliary contacts 5a and 5b. Current in this state, the movable auxiliary contact 4a from tap selector TS _1, 1st vacuum switch V
It flows to the neutral point or the line end N via S ₁ and the second vacuum switch VR ₁ . Next, FIG.
(F) according to a known contact sequence, each vacuum switch
The VS _1, VR _1, regular opening and closing of the VR ₂ and VS _2, was transferred from the tap selector TS ₁ of a current to the TS ₂ is performed. Circulating current in the middle tap bridge-circuit is summer as appropriately limited by resistors R ₁ and R _2. The current drawing (f) is completely moved to tap selector TS ₂ side, the movable auxiliary contact element 4b,
It flows to the neutral point or the line end N via the first vacuum switch VS ₂ and the second vacuum switch VR ₂ .

Further, in the same figure (g), when the movable main energizing contact 11 comes into contact with the fixed auxiliary contact 5b, the electric current passes through the movable main energizing contact 11 and the movable auxiliary contact 4b. diverted to a series circuit consisting of the vacuum switch VS ₂ and the second vacuum switch VR ₂ Prefecture. And finally, in the same figure (h),
It opens the pair of movable auxiliary contact element 4a and 4b, current passes through the tap selector TS ₂ from the tap winding TW, fixed auxiliary contact 5
b, flows to the neutral point or the line end N via the movable main energizing contact 11; This state is a normal state in which the tap selector TS ₂ is energized, and completely includes all the vacuum switches VS ₁ ,
VR ₁ , VR ₂ and VS ₂ are disconnected from the energizing circuit. Of course, then the current shifts from the tap selector TS ₂ the tap selector TS ₁ side operation, the opposite operation of the above described FIG. (H) ~
Needless to say, it is sufficient to carry out in the order of (a).

With the above configuration, all the vacuum switches are separated from the energizing circuit in the normal energized state, so that the burden on energization and voltage application of the vacuum switches is reduced, and the probability of vacuum leakage is lowered, as well as abnormal. Even if a surge voltage enters, no voltage is applied between the contacts of the vacuum switch, and no dielectric breakdown occurs.

Further, paying attention to the details of the circuit of FIG. 1, if if the first vacuum switch VS ₁ or VS ₂ was blocked incapable Ochiitsu the tap being switched by leakage vacuum, the second vacuum switch VR ₁ and VR _{If 2} is normal, it functions as a tap changer under all conditions including tap change operation.
Although it can be seen that operation can be continued without any apparent abnormality,
In any case, one vacuum switch remains defective. Assuming that only one vacuum switch is defective in this way, it is probable that two or more vacuum switches will be defective at the same time, and when considering a very short time between tap changes, This is because, even if a defect occurs, it is considered that the defect first occurs in one vacuum switch.

On the other hand, the second vacuum switch VR ₁ or V
R ₂ is, if was blocked incapable Ochiitsu the tap being switched by a vacuum leakage, it is considered that the time when energized as compared to the normal switching in resistors R ₁ or R ₂ is prolonged. 3 (a) to 3 (a) to 3 (a) to 3 (c) for the problems caused by the vacuum leakage of these vacuum switches.
During the switching of (f), the abnormality is detected by the detection circuit of the separate application, and the subsequent tap switching is locked,
All vacuum switches, including faulty vacuum switches, can be disconnected from the energized circuit to maintain a normal operating condition, while appropriate measures such as planned shutdown of transformers and promotion of regular inspections that do not interfere with equipment operation are taken. it can.

According to the switching sequence of FIG. 2, FIG.
The structure enabling the switching operation of (h) will be described in principle with respect to one phase of the mechanism with reference to FIGS. 4 (a) to 4 (c). In the figure, reference numeral 12 denotes rollers 13a to 13d and cam slopes 14a to 1
This is a vacuum switch opening / closing cam having 4d, and a neutral point or a line end N is provided in a part of the cam 12. With the reciprocation of the cam 12 in the direction of the arrow, the cam slopes 14a to 14d
The vacuum switches VS ₁ , VR ₁ , VR _2, and VS ₂ ride on and off the vacuum switches VS ₁ , VR ₁ , VR _2, and VS _{2 so} that the vacuum switches VS ₁ , VR ₁ , VR _2, and VS ₂ regularly follow the vacuum switch switching sequence shown in FIG. Open and close. At this time, the operation of the cam 12 is performed quickly, and its driving force is given by a spring force. A movable main energizing contact 11 is connected to the neutral point or the line end N, and the movable main energizing contact 11 is connected to a pair of contacts 15 by wipe springs 16a and 16b as shown in FIG. It is pressed so as to give a contact force, is rotatably supported at the neutral point or the line end N by the support pins 17 and 18, and is selectively connected to the fixed auxiliary contacts 5a and 5b.

On the other hand, reference numeral 19 denotes a tap selector drive shaft.
The upper marked with tap selector TS ₁ and TS ₂ (see FIG. 1) and the feed roller 20. The feed roller 20 meshes with the rotary gear 21 and the movable auxiliary contact 4a via the drive shaft 22.
A movable auxiliary contact directly connected to the switching arm 23 that opens and closes
4a and 4b are switched at an arbitrary angle (360 [deg.] = 60 [deg.] In FIG. 3A) for each tap change. The movable auxiliary contact 4a (the same applies to 4b) has a pair of contacts 24 and 25, as shown in FIG.
The support pins 28 are pressed to give contact force by the
It is held by a conductor 29 provided on the switching arm 23 by a to 28d. Then, by feeding the movable auxiliary contact 4a (4b), the first vacuum switch VS ₁ (VS ₂ ) passes through the movable auxiliary contact 4a (4b) to the fixed auxiliary contact 5a (5b). Is formed.

The state shown in FIG. 3A is the same as the state shown in FIGS. 1 and 3A, with the tap selector TS ₁ (see FIG. 1) closed, the movable main energizing contact 11 and the fixed auxiliary contact. 5a is in contact. At the same time, the first vacuum switch VS ₁ and the second vacuum switch VR ₁ are both closed, but the movable auxiliary contact 4
Because a and 4b are open, the vacuum switch is disconnected from the energizing circuit.

When switching from this state to the tap selector TS ₂ (see FIG. 1), first, the tap selector drive shaft 19 is rotated in an arbitrary direction, for example, clockwise by a drive source (not shown) such as a motor. Considering that, tap selector TS
₂ (see FIG. 1) is switched to the next tap in a state of no current, and starts accumulating a spring force for driving the cam 12. In synchronization with this, the feed roller 20 rotates the rotating gear 21 in a counterclockwise direction, and rotates the movable auxiliary contacts 4a and 4b in a counterclockwise direction via the drive shaft 22 and the switching arm 23, so that the fixed auxiliary contact 5a ,
Touch 5b. This state is the state shown in FIG.

When the tap selector drive shaft 19 continues to rotate, the cam
12 quickly performs the quick-turning operation by the driving spring and moves to the left in the figure. At this time, first, the contact 15 of the movable main energizing contact 11 comes off the fixed auxiliary contact 5a. This state is the state shown in FIG. Next, FIGS. 3 (d) to 3 (f)
The vacuum switch is opened and closed in the order described above, and the contact 15 of the movable main energizing contact 11 is thrown into the fixed auxiliary contact 5b at the final stage of the rapid cutting operation. This state is shown in FIG. 3 (g).

Finally, at the final stage of the rotation of the tap selector drive shaft 19, when the feed roller 20 makes one rotation and returns to the original position, the rotary gear 21 is again rotated counterclockwise, and the drive shaft 22 and the switching arm 23 are rotated.
Then, the movable auxiliary contacts 4a and 4b are rotated counterclockwise through the, and separated from the fixed auxiliary contacts 5a and 5b. This state is the third
FIG. The above configuration is symmetrical to the operation, and when switching from FIG. 3 (h) to (a) is performed, FIG. 4 (a) may be operated in the direction opposite to the above description. .

Therefore, such a structure enables the switching sequence of FIG. 2 and the switching operation of FIGS. 3 (a) to 3 (h) for any tap switching.

As described above, according to the present embodiment, at the normal energizing position, all the vacuum switches are completely disconnected from the energizing circuit by opening the auxiliary contacts, and the current flows through the movable main energizing contact, so that the vacuum switch causes vacuum leakage. It is possible to obtain a vacuum switch type tap changer circuit which can continue the operation even if it occurs.

FIG. 5 shows another embodiment of the present invention. This example vacuum switches switching the movable contact between the circuit of the vacuum switch type load tap changer, a husband 1st vacuum switch VS ₁ of s, VS ₂ and the second vacuum switch VR _1, VR ₂ Child 3
0a, 30b, and these vacuum switch switching movable contacts 30a, 30b are provided.
The neutral point or line end N and the second vacuum switch V at b
R ₁ and VR ₂ can be selectively connected. And provided with the respective resistors R _1, R ₂ the second vacuum switch VR _1, the resistance switching movable contact 31a between the VR _2, the 31b, the resistance switching movable contact 31a, the neutral point 31b or Either the line end N or the second vacuum switch VR ₁ or VR ₂ can be selected. By doing so, the same operation and effect as in the case described above can be obtained.

That is, the difference from FIGS. 1 and 3 is that a vacuum switch switching movable contact 30a (30b) is provided between the _first vacuum switch VS ₁ (VS ₂ ) and the neutral point or the neutral point. Vacuum switch switching fixed contact 32 directly connected to line end N
a, 32b or fixed contact 33a (33b) can be selected depending on the conditions. In the same figure, 34a and 34b are normal circuits and come into contact with the vacuum switch switching movable contact 30a or 30b, so
This is a fixed contact for connecting the second vacuum switch VS ₁ , VR ₁ and VS ₂ to VR ₂ in series.

Also, a parallel resistor R ₁ (R ₂ ) and a second vacuum switch
VR ₁ between the (VR _2), resistance switching the movable contact 31a a (31b) is provided, the fixed contact 33a (33b) or the second vacuum switch VR ₁ (VR ₂₎ side fixed contact 35a ( 35b) can be selected depending on the conditions.

In this circuit, when each vacuum switch is normal, the resistance switching movable contact 31a (31b) is connected to the fixed contact 35a (35b), and the vacuum switch switching movable contact 30a (30b) is fixed to the fixed contact 34a.
(34b), the same circuit as that of FIG. 1 is created, and the operation is performed according to the switching sequence and the switching operation diagram of FIG. 2 and FIG. Next, in this connection, if the first vacuum switch VS ₁ or VS ₂ cannot be shut off due to a vacuum leak, if the second vacuum switch VR ₁ or VR ₂ is normal, as described above. It is apparently possible to operate normally, and the operation including tap switching can be continued.
On the other hand, when the first second vacuum switch VR ₁ or VR ₂ is caused a defect by leakage vacuum, it is possible to continue the operation by locking the tap switching, normal to implement tap changeover in situ Operation is with resistance R ₁ or
Lead to abnormal overheating of R _2, is not possible continuation. Therefore, in this embodiment, it is apparently possible to continue the operation even under this condition, and its application will be described below.

The figure is obtained by assuming the case has decreased abnormally cause leakage vacuum second second vacuum switch VR ₂ is. in this case,
The resistance switching movable contact 31b and the vacuum switch switching movable contact 30b are connected to a fixed contact 33b, and the vacuum switch switching movable contact 30a is connected to a vacuum switch switching fixed contact 32a. For this reason, the second defective vacuum switch
VR ₂ is summer so as not to be inserted into the circuit in tap being switched. This circuit has the shape of a switching circuit of the second resistor 3 vacuum switch type, by selecting the resistance values of the resistors R ₁ and R ₂ properly, it is possible tap changeover after vacuum switch VR ₂ has come defect. The above description has shown the case where the second vacuum switch VR ₂ has failed. However, even if the other second vacuum switch VR ₁ has failed, this second vacuum switch VR ₂ is not affected by the circuit. by continuing the contact of the position of the switch VR ₁ and symmetry, it is possible to achieve the same effect.

Of course, in this circuit, even if an abnormal surge voltage enters in the normal operation state, the surge voltage is not applied between the contacts of the vacuum switch, the insulation does not break down, and the same effect as in the above case is obtained.

FIG. 6 shows still another embodiment of the present invention.
This embodiment is a case where the present invention is applied to a circuit of a one-resistance, three-vacuum switch type tap changer under load. In this case, the same operation and effect as in the above case can be obtained.

That figure shows a normal state where the tap selector TS ₁ is energized, the fixed auxiliary contact 5a and the movable main conductive contact 11 has contacts, the movable auxiliary contact 4a and 4b are open. Accordance connexion current passes through the tap selector TS ₁ from the tap winding TW, fixed auxiliary contact 5a, via the moving main conductive contact 11 is flowing through the neutral point or the line end N. All of the vacuum switch VS ₁ in this state, VR ₁ and VS ₂ is independent of the energizing circuit. Tap is switched in this state, for the operation current passes from tap selector TS ₁ to TS ₂ side, the movable auxiliary contact element 4a and 4b, the operation of the fixed auxiliary contact 5a and 5b and the movable main conductive contact 11, Are the above-mentioned FIGS.
This is the same as the switching operation diagram shown in (h) and the switching sequence shown in FIG. 2, and the first vacuum switch VS ₁ ,
The operations of the VS ₂ and the second vacuum switch VR ₁ are performed according to a known sequence, and thus the description is omitted.

By doing so, even in the circuit of this embodiment, all the vacuum switches are separated from the energizing circuit in the normal energizing state, so that the same effect as in the above-described case can be obtained.

〔The invention's effect〕

As described above, the present invention enables the operation to be continued even if the vacuum switch causes a vacuum leak, and the circuit of the vacuum switch type on-load tap changer capable of continuing the operation even if the vacuum switch causes the vacuum leak. Can be obtained.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of one embodiment of a circuit of a vacuum switch type tap changer according to the present invention, FIG. 2 is a switching sequence diagram of FIG. 1, and FIGS. 1A is a circuit diagram showing the same state as FIG. 1 and FIG.
(B) is a circuit diagram showing a state where the movable auxiliary contact is in contact with the fixed auxiliary contact, (c) is a circuit diagram showing a state where the movable main energizing contact is separated from the fixed auxiliary contact, and (d) to (d). f) shows the regular opening and closing of the vacuum switch in accordance with the contact sequence, (d) is a circuit diagram showing a state in which the _first vacuum switch VS1 is open, and (e) is a circuit diagram showing the second vacuum switch VR.
Circuit diagram showing a state _{where 2} is closed, (f) the first second vacuum switch VR ₁ is opened, the circuit diagram showing a state where the first vacuum switch VS ₂ is closed, (g) the movable main current contacts FIG. 4H is a circuit diagram showing a state in which the child contacts a fixed auxiliary contact that is different from the case of FIG. 4A, FIG. 4H is a circuit diagram showing a state in which the movable auxiliary contact is separated from the fixed auxiliary contact, FIG. 1 (a) to (c) show the mechanism of FIG. 1, (a) is an explanatory view showing the mechanism, (b) is a cross-sectional view taken along line AA of (a), and (c) is ( FIG. 5 is a sectional view taken along the line BB of FIG. 5A, and FIGS. FIG. 8 is a circuit diagram showing a circuit of a conventional switch type load tap changer. FIG. 8 is a circuit diagram showing another example of a circuit of a conventional vacuum switch type load change tap switch. 4a, 4b …… Movable auxiliary contact, 5a, 5b …… Fixed auxiliary contact,
11… Movable main energizing contact, 30a, 30b …… Vacuum switch switching movable contact, 31a, 31b …… Resistance switching movable contact, TW…
… Tap winding, TS ₁ , TS ₂ … Tap selector, VS ₁ , VS ₂ ……
1st vacuum switch, VR _1, VR ₂ ...... first second vacuum switch, R _1, R ₂ ...... resistance, N ...... neutral point or the line end.

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-60-189125 (JP, A) JP-A-1-173613 (JP, A) JP-A-62-55915 (JP, A)

Claims (3)

(57) [Claims] A tap winding and a pair of tap selectors;
First and second two vacuum switches connected in series to these tap selectors, respectively; and resistors connected in parallel to the first vacuum switch on the tap selector side of these vacuum switches, In a circuit of a vacuum switch type tap changer in which a neutral point or a line end is formed at a connection portion connecting the ends of the second vacuum switches opposite to the tap selector, Between the tap selector and each of the first vacuum switches, there is provided an auxiliary contact capable of separating all of the first and second vacuum switches from the energizing circuit, and fixed auxiliary contacts of the auxiliary contact. A movable auxiliary contact disposed on the tap selector side, a movable auxiliary contact disposed on the first vacuum switch side, and a pair of fixed auxiliary contacts selectively connected to the neutral point or a line end. Circuit vacuum switch type load tap changer, characterized in that a conductive contact. 2. The circuit of a vacuum switch type tap changer according to claim 1, further comprising a vacuum switch switching movable contact between said first vacuum switch and said second vacuum switch. A vacuum switch switching movable contact can be selectively connected to either the neutral point or the line end and the second vacuum switch, and between each of the resistors and the second vacuum switch. 2. A resistance switching movable contact, wherein the resistance switching movable contact is adapted to select either the neutral point or the line end and a second vacuum switch. The circuit of the described vacuum switch type tap changer under load. 3. A tap winding and a pair of tap selectors,
A first vacuum switch connected in series to each of the tap selectors, and a second vacuum switch and a resistor connected in series to the first vacuum switch on one side of the vacuum switch. A vacuum switch in which a neutral point or a line end is formed at a connection portion connecting the resistor of the series connection body opposite to the tap selector and the end of each of the first vacuum switches. In the circuit of the on-load tap changer, between the respective tap selectors and the respective first vacuum switches, all of the first and second vacuum switches can be separated from the energizing circuit. A fixed auxiliary contact of the auxiliary contact is disposed on the tap selector side, a movable contact is disposed on the first vacuum switch side, and the pair of fixed auxiliary contacts are selected. Circuit vacuum switch type load tap changer, characterized in that a movable main current contacts connected to the neutral point or line end to.