KR100814514B1 - On-load tap changer - Google Patents

Abstract

By reducing the maximum value of the breaking current in the main bulb with a large number of interruptions, the on-load tap-changing device which suppresses the consumption of the electrode contacts of the main bulb and stabilizes the breaking capability is provided.

It is comprised so that the main bulb H may open when the resistance bulb W1 of the tap side which is energized before a switching operation is a closed electrode, and the resistance bulb W2 of the tab side which is not energized before a switching operation is an open electrode.

Description

On-load tap changer {ON-LOAD TAP CHANGER}

1 is a switching circuit and an operation diagram of a first embodiment according to the present invention.

FIG. 2 is a switching sequence diagram of the first embodiment shown in FIG. 1. FIG.

3 is a switching circuit and an operation diagram of a second embodiment according to the present invention;

FIG. 4 is a switching sequence diagram of the second embodiment shown in FIG. 3. FIG.

5 is a switching circuit and an operation diagram of a third embodiment according to the present invention.

Fig. 6 is a switching sequence diagram of the third embodiment shown in Fig. 5.

7 is a switching circuit and an operation diagram of a fourth embodiment according to the present invention.

FIG. 8 is a switching sequence diagram of the fourth embodiment shown in FIG. 7. FIG.

9 is a switching circuit and an operation diagram of another embodiment according to the present invention.

FIG. 10 is a switching sequence diagram of another embodiment shown in FIG. 9. FIG.

11 is a switching circuit and an operation diagram of still another embodiment according to the present invention;

FIG. 12 is a switching sequence diagram of still another embodiment shown in FIG. 11. FIG.

13 is a switching circuit and an operation diagram of a conventional switching switch.

14 is a switching sequence diagram in a conventional switching switch.

[Description of Symbols for Main Parts of Drawing]

2, 3: tap A, H of tap winding, main valve

C, D, W1, W2: resistance valve

CA, CB: energized contact fixed contact C1, C2: energized contact

h: changeover switch movable contact

h1, h2: fixed switching switch contact IL: load current

IC: cyclic current

M1, M2: tap selector movable contact N: neutral point

R1, R2: current limiting resistor S: changeover switch

SA, SB: Fixed contact of changeover switch

SC: movable contact of changeover switch TW: tap winding

US: Tap-to-Tap Voltage 100: Overvoltage Protector

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an on-load tap-changing device of a two-resistor three-valve type, and more particularly, to an on-load tap-changing device in which the breaking current of a main valve constituted by a vacuum valve is reduced to suppress consumption of electrode contacts of the vacuum valve.

In general, an on-load tap changer is used for a transformer connected to a power distribution system to regulate and stabilize the voltage of the power distribution system. The on-load tap changer is composed of a changeover switch and a tap selector. A switch valve is usually used as a blocking element, and a vacuum valve configured by arranging a pair of electrodes that can be separated from each other in a vacuum container is used. A switching resistor (see Patent Document 1) of a two-resistor three-valve type having a current limiting resistor and three vacuum valves has been proposed.

Here, with reference to FIG. 13 and FIG. 14, the on-load tap-changing apparatus of the 2-resistor 3-valve system of patent document 1 is demonstrated concretely. FIG. 13 is a diagram showing a switching circuit and its operation in the conventional on-load tap switching device, and FIG. 14 is a diagram showing the switching sequence.

In the code | symbol shown in FIG. 13, TW is a tap winding of a transformer etc., 2 and 3 are taps of the tap winding TW, M1 and M2 are two movable contacts of the tap selector which selects the taps 2 and 3. As shown in FIG. A, C, and D are vacuum valves, respectively, and A is called the main valve, C, and D are resistance valves. R1 and R2 are current limiting resistors, h1 and h2 are fixed contacts of the changeover switch, and h is a movable contact of the changeover switch for selecting one of the fixed contacts h1 and h2.

Between the taps 2 and 3 of the tapped winding TW and the neutral point 4, the movable contact M1, the current limiting resistor R1, the resistance valve C and the movable contactor M2, and the current limiting resistor ( R2) and a resistance valve D are provided. More specifically, the movable contact M1 and the current limiting resistor R1 and the resistance valve C and the movable contactor M2 and the current limiting resistor (A) at one end of the tabs 2 and 3 of the tap winding TW. R2) and the resistance valve D are connected in series, respectively, and the other end thereof is connected to the neutral point 4. Moreover, one end of the main valve A is connected to the movable contact h of the changeover switch, and the other end thereof is connected to the neutral point 4.

Fig. 14 shows the opening and closing states of the contacts in the fixed contacts h1 and h2 of the respective vacuum valves A, C, and D and the switchgear. It means open non-contact. 13A to 13F show the switching process shown in FIGS. 14A to 14F. Hereinafter, each process is demonstrated in order.

(A) Operation state [Fig. 13 (A)]

Here, the main valve A and the resistance valve C are closed, the resistance valve D is opened, and the movable contact h of the changeover switch selects the fixed contact h1. Indicates. At this time, the load current IL flows from the neutral point 4 to the circuit called the tap winding TW through the main valve A, the movable contact h of the changeover switch, and the fixed contact h1 as shown by the dotted line. This circuit is said to be able to protect between taps because an overvoltage, such as a surge, is temporarily applied and it breaks down between poles of the resistance valve D, even though it breaks between taps through the current limiting resistor R2. It is composed.

(B) Closed electrode of resistance valve D on the non-energized tap side [FIG. 13 (B)]

When switching operation starts in the state of said (A), first, the resistance valve D of the tap side which does not energize before switching operation closes. That is, all three valves A, C, and D are closed. The closed electrode of the resistance valve D forms a short circuit through the current limiting resistor R2, the resistance valve D, and the main valve A, where a circulating current IC flows. In addition, while the load current IL is in the state of said (A), from the neutral point 4, through the main valve A, the movable contact h of the changeover switch, and the fixed contact h1, the movable contact of the tap selector ( M1) flows through a circuit called the tap 2.

(C) Opening of main valve A [FIG. 13 (C)]

Subsequently, in a state in which all three valves A, C, and D are closed, the main valve A is opened, and the combination of the load current IL and the circulating current IC that flowed as shown in the above (B) is performed. Block the value. After the shut-off, through the movable contactor M2, the current limiting resistor R2, the resistance valve D, the resistance valve C, the current limiting resistor R1, and the movable contactor M1 of the tab 3, A short circuit is formed between the tab 2 and the circulating current IC flows therethrough.

In addition, the load current IL is a current from the neutral point 4 to a circuit composed of the resistance valve C and the current limiting resistor R1, and a circuit composed of the resistance valve D and the current limiting resistor R2. It classifies according to the resistance ratio of limiting resistors R1 and R2. Here, R1 = R2. That is, the load current IL flows in the current limiting resistor R1, the circuit of the resistance valve C, the current limiting resistor R2, and the circuit of the resistance valve D.

(D) Operation of the changeover switch [FIG. 13 (D)]

Next, the movable contact h of the changeover switch in the state of not energizing moves from the fixed contact h1 to the fixed contact h2.

(E) Closed pole of main valve A [FIG. 13 (E)]

Subsequently, the main valve A closes. Accordingly, the load current IL is moved from the neutral point 4 through the main valve A, the movable contactor h of the changeover switch, and the fixed contact h2 to the circuits such as the movable contactor M2 of the tap selector and the tap 3. Flows on. The circulating current IC remains in the state of (C) above.

(F) Opening of resistance valve C on energized tap 2 side [FIG. 13 (F)]

Finally, the circulating current IC is cut off by opening the resistance valve C on the side of the tap 2 that is energized before the switching operation. This completes the switching operation and continues operation in the state shown in Fig. 13F. In addition, the switching operation to the next tap is performed in order from (F) to (A) as shown in Fig. 14 (2).

The maximum values of the cutoff currents of the main valve A and the resistance valves C and D when the switching operation is performed by the above-described switching circuit are as follows. When the step voltage between the taps 2 and 3 of the tap winding TW is US, the breaking current of the main valve A is combined with the load current IL and the circulating current IC as shown in FIG. 13 (B). Value, and IL + IC = IL + US / R1. In addition, the interruption currents of the resistance valves C and D become the circulating current IC as shown in Fig. 13F, and IC = US / (2 × R1).

[Patent Document 1] Japanese Patent Laid-Open No. 61-15569

However, the following problems have been pointed out in the above prior art. That is, in the switching circuit shown in Fig. 13, the switching operation of the resistance valves C and D is alternate. That is, the resistance valves C and D cut off the current at the rate of one switching operation twice. In contrast, the main valve A cuts off the current each time the switching operation is performed.

Therefore, even simple thinking, the number of switching operations in the main valve A is twice the number of switching operations of the resistance valves C and D. Moreover, the blocking current of the resistance valves C and D is only the circulating current IC = US / (2 x R1), but the breaking current of the main valve A is the combined value of the load current IL and the circulating current IC. IL + IC = IL + US / R1, and the main valve A has a larger breaking current than the resistance valves C and D.

It is known that arc contacts provided on opposite surfaces of a pair of electrodes of a vacuum valve that cut off current are consumed by an arc, but the greater the number of interruptions or the larger the current, the greater the consumption. Therefore, it can be said that the consumption of the main valve A is much easier to proceed than the resistance valves C and D. If the deterioration of the contact state progresses, there is a possibility that an arc or re-ignition for a long time after the arc continues. That is, in the conventional on-load tap-changing device, the problem is that the consumption of the electrode contact of the main valve is excessive.

SUMMARY OF THE INVENTION The present invention has been proposed to solve the above problems, and its object is to reduce the maximum value of the breaking current in the main valve with a large number of shutoffs, thereby suppressing the consumption of electrode contacts in the main valve and stabilizing the breaking capability. The present invention provides an on-load tap-changing device.

In order to achieve the above object, the present invention provides two first movable contacts of a tap selector for selecting a tab of a tab winding, and between these first movable contacts and a neutral point, in series with each of the first movable contacts. A plurality of fixed contacts provided respectively between the first movable contactor and the current limiting resistor and a second movable one for selecting one of the plurality of fixed contacts, respectively provided with a current limiting resistor and a resistance valve connected to each other. The main valve is connected between the switching switch made of a contactor and the second movable contactor and the neutral point of the switching switch, and the resistance valve on the tab side that is energized before the switching operation is closed, and the resistance on the tab side that does not energize before the switching operation. When the valve is open, the main valve is configured to open.

In the present invention, the tap-side resistance valve that is energized before the switching operation is a closed electrode, and the tap-resistance valve that is not energized before the switching operation is closed in a state where the tap-side resistance valve that is not energized before the switching operation is opened. First of all, since the main valve is opened, the load current flows through the circuits of the resistance valve, the current limiting resistor, and the tap winding in the closed electrode state, and the maximum value of the breaking current of the main valve can be suppressed lower than before.

EMBODIMENT OF THE INVENTION Hereinafter, typical embodiment which concerns on this invention is described concretely with reference to FIGS. 1, 3, 5, 7, 9, and 11 show a switching circuit diagram and an operation diagram of an embodiment according to the present invention, the same reference numerals being used for the same parts as the prior art shown in FIG. And omit the description. 2, 4, 6, 8, 10, and 12 correspond to FIGS. 1, 3, 5, 7, 9, and 11, respectively, and according to the present invention, the switching of the embodiment according to the present invention is performed. It shows the sequence.

(1) First embodiment

EMBODIMENT OF THE INVENTION The 1st Embodiment which concerns on this invention is described with reference to FIG. 1 and FIG. Fig. 1 shows a switching circuit and an operation diagram of an on-load tap switching device according to the first embodiment, and Fig. 2 shows the switching sequence.

(1-1) Configuration

Reference numerals M1 and M2 shown in FIG. 1 denote two movable contacts of the tap selector for selecting the taps 2 and 3 of the tap winding TW, and the reference numeral N denotes a neutral point. Between the taps (2, 3) and the neutral point (N), the movable contact (M1, M2), respectively, the current limiting resistor (R1), the resistance valve (W1), the current limiting resistor (R2) and the resistance valve (W2) in series Is connected to the neutral point (N).

In addition, a fixed contact SA of the changeover switch S is provided at the middle of the movable contact M1 and the current limiting resistor R1, and is provided at the middle of the movable contact M2 and the current limiting resistor R2. The fixed contact SB of the changeover switch S is provided. Close to these fixed contacts SA and SB, movable contactors SC of the selector switch S for selecting either of the fixed contacts SA and SB are provided, and these fixed contacts SA and SB and The changeover switch is configured at the movable contact SC. Furthermore, the main valve H is connected between the movable contact SC of the switching switch S, and the neutral point N. As shown in FIG.

The characteristic of the structure of this embodiment is as follows. First, the case where electricity is supplied from the tab 2 side is described as an example. The main valve H is in a state where the resistance valve W1 on the side of the tap 2 that is energized before the switching operation is closed, and the resistance valve W2 on the side of the tab 3 that is not energized before the switching operation is open. It is supposed to open.

Then, the resistance valve W1 on the side of the tap 3 where the main valve H is open and energized before the switching operation is not energized before the closing electrode and the switching operation. In the state where is an open pole, the movable contact SC of the changeover switch S starts to operate, and the electrical connection with the fixed contact SA that was in contact before the changeover operation is released. After that, the resistance valve W2 on the side of the tab 3 that is not energized before the switching operation is configured to be closed.

(1-2) switching sequence

The above features will be described in order according to the switching process shown in Figs. 1A to 1F. 1A to 1F show the switching process shown in FIGS. 2A to 2F.

(A) Operation state [(A) of FIG. 1]

The main valve (H) and the resistance valve (W1) are closed (ON), the movable contact (SC) of the changeover switch (S) is connected to the fixed contact (SA), and the movable contact (M1) of the tap selector is the tap winding. The operation state connected to (TW) is shown. At this time, the load current IL flows to the circuits such as the main valve H, the movable contact SC of the changeover switch S, the fixed contact SA, and the tap winding TW at the neutral point N as shown by the dotted line.

(B) Opening of main valve H [Fig. 1 (B)]

When the switching operation starts from the state of the above (A), in the past, the resistance valve on the non-conductive tap side was first closed (state of FIG. 13B), but in the present embodiment, the main valve H is first opened. . As a result, the load current IL flows from the neutral point N to the circuits of the resistance valve W1, the current limiting resistor R1, and the tap winding TW as shown by the dotted line in FIG.

(C) Closed pole of resistance valve W2 on the non-energized tap 3 side (FIG. 1C)

Subsequently, the resistance valve W2 on the side of the tap 3 that does not energize before the switching operation closes, and the current limiting resistor R2, the resistance valve W2 and the resistance valve W1, and the current limiting resistor ( Through R1), a short circuit is formed, in which a circulating current IC flows.

The load current IL is limited from the neutral point N to the circuit of the resistance valve W1, the current limiting resistor R1, the circuit of the resistance valve W2, and the current limiting resistor R2. It is classified according to the resistance ratio of the resistors R1 and R2. Here, R1 = R2. That is, as shown in FIG. 1D, the load current IL is formed from the neutral point N by the resistance valve W1, the circuit of the current limiting resistor R1, the resistance valve W2, and the current limiting resistor R2. The circuit flows in two minutes.

(D) Operation of the changeover switch S [Fig. 1 (D)]

Next, the movable contact SC of the changeover switch S starts to move from the fixed contact SA on the movable contact M1 side to the fixed contact SB on the movable contact M2 side.

(E) Closed pole of main valve (H) [(E) of FIG. 1]

Furthermore, the movable contact SC of the changeover switch S contacts the fixed contact SB, and the main valve H closes. The circulating current IC flows through the current limiting resistor R2, the resistance valve W2, the resistance valve W1, and the current limiting resistor R1 in the state of FIG. The load current IL passes from the neutral point N to the main valve H, the movable contact SC of the selector switch S, and the fixed contact SB, as shown by the dotted line, from the movable contact M2 of the tap selector to the tap ( 3) Move to a circuit called tap winding (TW).

(F) Opening of resistance valve W1 at energized tap 2 side [FIG. 1 (F)]

Finally, the resistance valve W1 on the side of the tap 2 that is energized before the switching operation opens and cuts off the circulating current IC. This completes the switching operation and continues the operation in the state of FIG. 1 (F). In addition, switching operation to the next tap is performed in order from (F) to (A) shown in FIG.

(1-3) Effects

The operational effects of the first embodiment having the above switching sequence are as follows. That is, in the state where the resistance valve W1 of the energization tap 2 side before a switching operation is a closed electrode, and the resistance valve W2 of the non-energization tab 3 side is an open electrode before a switching operation, the non-energization tap 3 is carried out. Since the main valve H opens before the resistance valve W2 on the side closes, the load current is a circuit called a resistance valve W1, a current limiting resistor R1, and a tap winding TW in a closed electrode state. To flow.

Therefore, the maximum value of the breaking current of the main valve H is the main valve H as the load current IL, and the resistance valve W1 as US / (2 × R1). That is, compared with the maximum value of the breaking current of the main valve A in the conventional switching switch, IL + US / R1, in this embodiment, the maximum value of the breaking current of the main valve H can be suppressed small.

Thereby, consumption of the electrode contact of the main valve H can be suppressed, and the vacuum valve which comprises a switching switch can exhibit the stable breaking capability. In addition, in the state of FIG. 1C, even when the failure of the main valve H is interrupted, the switching switch S can forcibly open the circuit. For this reason, the electric current interruption | blocking by the switching switch S is attained, and reliability can be improved.

(2) 2nd Embodiment

A second embodiment according to the present invention will be described with reference to FIGS. 3 and 4.

(2-1) Configuration

About the circuit structure of 2nd Embodiment, although it is the same as that of the said 1st Embodiment, the switching sequence is different. In the second embodiment, the resistance valve W2 on the side of the tab 3 that is not energized before the switching operation closes, and the resistance valve W1 on the side of the tab 2 that is energized before the switching operation opens. After that, the switching sequence is configured such that the main valve H is closed.

(2-2) switching sequence

The above features will be described in order according to the switching process shown in Figs. 3A to 3F. 3A to 3F show the conversion process shown in FIGS. 4A to 4A.

In the switching sequence in the second embodiment, the flow from the (A) operation state in the first embodiment to the operation of the (D) changeover switch is the same, and (E) in the first embodiment. It can be said that the closed electrode of the main valve H and the opening of the resistance valve W1 of the (F) energization tap 2 side were replaced. That is, the following switching sequence is obtained.

(A) Operation state [Fig. 3 (A)]

The main valve H and the resistance valve W1 are closed, the movable contact SC of the selector switch S is connected to the fixed contact SA, and the movable contact M1 of the tap selector is the tap winding TW. It is connected to the tab 2 of. At this time, the load current IL is moved from the neutral point N to the main valve H, the movable contact SC of the changeover switch S, the fixed contact SA, the movable contact M1, and the tap 2 as shown in the dotted line. Flows in a circuit called a tap winding (TW).

(B) Opening of main valve H [Fig. 1 (B)]

When the switching operation starts from the state of the above (A), in the present embodiment, the main valve H is first opened. Accordingly, the load current IL flows through the circuits such as the resistance valve W1, the current limiting resistor R1, and the tap winding TW as shown by the dotted line.

(C) Closed pole of resistance valve W2 on the non-electric tap 3 side (FIG. 3C)

Subsequently, the resistance valve W2 on the side of the tap 2 that is not energized before the switching operation closes, and the current limiting resistor R2, the resistance valve W2, the resistance valve W1, and the current limiting resistor ( Through R1), a short circuit is formed, in which a circulating current IC flows.

The load current IL is a circuit composed of a resistance valve W1 and a current limiting resistor R1 from a neutral point N, and a circuit composed of a resistance valve W2 and a current limiting resistor R2. It is classified according to the resistance ratio of the current limiting resistors R1 and R2. Here, R1 = R2. That is, the load current IL flows into the circuit of the resistance valve W1, the current limiting resistor R1, the circuit of the resistance valve W2, and the current limiting resistor R2 for two minutes.

(D) Operation of the changeover switch S (FIG. 3D)

Next, the movable contact SC of the changeover switch S starts moving from the fixed contact SA to the fixed contact SB side.

(E) Opening of resistance valve W1 on the energized tap side [FIG. 3E]

After the movable contact SC of the selector switch S moves from the fixed contact SA to the fixed contact SB, the resistance valve W1 on the side of the tap 2 that is energized before the switching operation is opened, Shut off circulating current (IC). At this time, the load current IL flows in a circuit called a resistance valve W2, a current limiting resistor R2, and a tap winding TW as shown by a dotted line.

(F) Closed pole of main valve H [FIG. 3 (F)]

Finally, the main valve H closes, and the load current IL is moved from the neutral point N to the main valve H, the movable contact SC of the changeover switch S, the fixed contact SB, and the tap winding TW. Go to the circuit of. This completes the switching operation and continues driving in the state of the city. In addition, the switching operation to the next tap is performed in order from (F) to (A) shown in FIG. 4 (2).

(2-3) Effects

The second embodiment having the above switching sequence has the following effects in addition to the effect (the suppression of consumption of the electrode contacts of the main valve H and the reliable current interruption by the switching switch S) in the first embodiment. It has the same effect of the reader.

That is, when the operation sequence of each valve of (A) of FIG. 4 (2) which is a switching operation | movement to a next tap is made to operate | move the reverse operation | movement of a previous tap by the above-mentioned sequence (FIG. 4). (F) to (A)] in (1). For this reason, the opening / closing drive of the vacuum valve which comprises the main valve H and the resistance valves W1 and W2 can be set as the structure which can reciprocate with the same axis. Thereby, the opening and closing drive of the stable vacuum valve which does not require a special drive device part and does not depend on a switching direction can be obtained, and implement | achieves the simplification of a mechanism and the improvement of operation reliability.

(3) Third embodiment

A third embodiment according to the present invention will be described with reference to FIGS. 5 and 6.

(3-1) Configuration

About the circuit structure of 3rd Embodiment, although it is the same as that of the said 1st Embodiment, the closed-pole operation | movement of the resistance valve W2 of the non-electrical tap 3 side is carried out for disconnection operation | movement of the switching switch S in a switching sequence. This is done before.

That is, the resistance valve W2 on the side of the tap 3, in which the main valve H is open and energized before the switching operation, does not energize before the closing electrode, the switching operation. In the state where is an open pole, the movable contact SC of the changeover switch S starts operation, and releases the electrical connection with the fixed contact SA that was in contact before the changeover operation.

Subsequently, the resistance valve W2 on the side of the tap 3 that is not energized before the switching operation closes, and then the resistance valve W1 on the side of the tab 2 that is energized before the switching operation opens. Finally, the main valve H is closed.

(3-2) switching sequence

That is, in the switching sequence in the third embodiment, the closed electrode of the resistance valve W2 on the (C) non-conductive tap 3 side in the first embodiment, and (D) the switching switch S The operation of is replaced, and the same applies to (A), (B), (E), and (F) in the first embodiment. That is, the following switching sequence is obtained.

(A) Operation state [FIG. 5A]

The main valve H and the resistance valve W1 are closed, the movable contact SC of the selector switch S is connected to the fixed contact SA, and the movable contact M1 of the tap selector is the tap winding TW. Indicates an operating state connected to. At this time, the load current IL flows from the neutral point N to the circuits of the main valve H, the movable contact SC of the changeover switch S, the fixed contact SA, and the tap winding TW as shown by the dotted line.

(B) Opening of main valve H [Fig. 5 (B)]

When switching operation starts from the state of said (A), in this embodiment, the main valve H will open first. Accordingly, the load current IL flows through the circuits such as the resistance valve W1, the current limiting resistor R1, and the tap winding TW as shown by the dotted line.

(C) Operation of the changeover switch S [Fig. 5 (C)]

After the main valve H opens, the movable contact SC of the selector switch S moves from the fixed contact SA to the fixed contact SB.

(D) Closed pole of resistance valve W2 on the non-energized tap side [FIG. 5 (D)]

Subsequently, the resistance valve W2 on the side of the tap 3 that does not energize before the switching operation closes, and the current limiting resistor R2, the resistance valve W2, the resistance valve W1, and the current limiting resistor ( Through R1), a short circuit is formed, and the circulating current IC flows.

(E) Closed pole of main valve H [FIG. 5E]

Furthermore, the movable contact SC of the changeover switch S contacts the fixed contact SB, and the main valve H closes. The circulating current IC flows through the current limiting resistor R2, the resistance valve W2, the resistance valve W1, and the current limiting resistor R1 in the state shown in FIG. The load current IL moves to circuits such as the main valve H, the changeover switch S, the movable contactor M2, the tap 3, and the tap winding TW as shown by the dotted line.

(F) Opening of resistance valve W1 on the energized tap side

Finally, the resistance valve W1 on the tap side, which is energized before the switching operation, opens and interrupts the circulating current IC. This completes the switching operation and continues operation in the state of FIG. 5 (F). In addition, the switching operation to the next tap is performed in order from (F) to (A) shown in FIG. 6 (2).

(3-3) Effects

The third embodiment having the above switching sequence has the following effects in addition to the effect of the first embodiment, that is, suppression of consumption of the electrode contact of the main valve H and reliable interruption of current by the switching switch S. It has the same effect.

That is, in the state of FIG. 5C, before the resistance valves W1 and W2 are closed and the short circuit is formed between the taps 2 and 3 through the current limiting resistors R1 and R2, the switching switch ( Since the disconnection operation of S) is started, the load current IL is changed by the changeover switch S in the state shown in FIG. 5C even when a breakdown failure due to electrode contact damage or the like occurs at the time of opening of the main valve H. Can only block At this time, since the circulating current IC does not overlap, it becomes possible to suppress the maximum value of the breaking current in the changeover switch S. FIG. Thereby, there is a merit that the electrode contact of the changeover switch S can be made compact.

(4) Fourth Embodiment

A fourth embodiment according to the present invention will be described with reference to FIGS. 7 and 8.

(4-1) Configuration

In 4th Embodiment, the energization contactors C1 and C2 are connected with respect to the neutral point N. As shown in FIG. In addition, an energization contact fixed contact CA is provided between the movable contactor M1 and the current limiting resistor R1, and an energization contact fixed contact CB is installed between the movable contactor M2 and the current limiting resistor R2. do. The energization contactor C1 is a contactor which enables the connection and release of the energization contact fixed contact CA and the neutral point N, and the energization contactor C2 connects the energization contact fixed contact CB and the neutral point N, The contact who made the release possible.

(4-2) switching sequence

The above features will be described in order according to the switching process shown in Figs. 7A to 7H. 7A to 7H show the conversion process shown in Figs. 8A to 8A.

(A) Operation state [FIG. 7A]

The main valve H and the resistance valve W1 are closed, the movable contact SC of the selector switch S is connected to the fixed contact SA, and the energized contact C1 is connected to the energized contact fixed contact CA. The operating contact M1 of the tap selector is connected to the tap 2 of the tap winding TW. At this time, the load current IL is formed from the neutral point N to the main valve H, the movable contact SC of the changeover switch S, the fixed contact SA, and the tap winding TW, as shown by the dotted line, and the neutral point ( From N), it is classified into circuits, such as the energizing contact C1, the contact CA, and the tap winding TW.

(B) Release of energization contactor C1 (FIG. 7B)

When the switching operation is started from the state of the above (A), first, the energization contactor C1 releases from the contact CA. The load current IL flows from the neutral point N to the circuits of the main valve H, the movable contact SC of the changeover switch S, the fixed contact SA, and the tap winding TW as shown by the dotted line.

(C) Opening of main valve H [C in Fig. 7]

Subsequently, the main valve H opens. The load current IL flows in a circuit called a resistance valve W1, a current limiting resistor R1, and a tap winding TW as shown by a dotted line.

(D) The closed electrode of the resistance valve W2 on the non-electric tap 3 side (FIG. 7D).

Next, the resistance valve W2 on the side of the tap 3 that is not energized before the switching operation closes, and the current limiting resistor R2, the resistance valve W2, the resistance valve W1, and the current limiting resistor ( Through R1), a short circuit is formed, and a circulating current IC flows.

The load current IL is a current limiting resistor at the neutral point N in the circuit of the resistance valve W1, the current limiting resistor R1 and the circuit of the resistance valve W2, the current limiting resistor R2. It is classified according to the resistance ratio of (R1, R2). Here, R1 = R2. That is, the load current IL flows through the resistance valve W1, the circuit of the current limiting resistor R1, the resistance valve W2, and the circuit of the current limiting resistor R2.

(E) Operation of the changeover switch S [Fig. 7E]

Further, the movable contact SC of the changeover switch S starts to move from the fixed contact SA to the fixed contact SB side.

(F) Opening of resistance valve W1 at energized tap 2 side [FIG.7 (F)]

After the movable contact SC of the selector switch S moves from the fixed contact SA to the fixed contact SB, the resistance valve W1 on the side of the tap 2 that is energized before the switching operation is opened. The load current IL flows in a circuit called a resistance valve W2, a current limiting resistor R2, a movable contact M2, a tap 3, and a tap winding TW as shown by a dotted line.

(G) Closed pole of main valve H [Fig. 7 (G)]

After the resistance valve W1 opens, the main valve H closes, and the load current IL is moved from the neutral point N to the main valve H, the movable contact SC of the changeover switch S, and the fixed contact SB. ), A circuit called a tap winding (TW).

(H) Connection of energization contactor C2 [FIG. 7 (H)]

Finally, the energization contactor C2 is connected to the energization contact fixed contact CB, so that the load current IL is moved from the neutral point N to the main valve H and the movable contact SC of the changeover switch S as shown by the dotted line. , Fixed contacts (SB), movable contacts (M2), taps (3), tap windings (TW), and energized contacts (C2), contacts (CB), movable contacts (M2), taps from the neutral point (N) (3) It is classified into a circuit called a tap winding (TW). This completes the switching operation and continues the driving in the state of the city. In addition, the switching operation to the next tap is performed in order from (H) to (A) shown in FIG. 8 (2).

(4-3) Effects

In the fourth embodiment having the switching sequence as described above, the operation of the energizing contacts C1 and C2 for contact separation between the energizing contact fixed contacts CA and CB is added to the switching sequence of the second embodiment.

That is, similarly to the second embodiment, the operation sequence of the vacuum valve of Fig. 8 (2) (A), which is the switching operation to the next tap, is operated when the switching operation of the previous tap is reversed (Fig. 8 (1) to (A)]. For this reason, the effect of the simplification of a vacuum valve opening / closing drive apparatus and the improvement of operation reliability can be acquired.

In addition, the original action and effect of the fourth embodiment are as follows. That is, the load current IL is classified into the energized contactor C1 and the main valve H, or the energized contactor C2 and the main valve H in the normal operating state (Fig. 7 (A) or (H)). . When the load current IL is energized only by the main valve H, the contact load between the electrodes of the main valve H is increased so as to suppress the temperature rise of the electrode in the energized state, and the contact resistance between the electrodes is reduced. Should be.

The load current IL in the normal operation state (Fig. 7 (A) or (H)) can be classified into the energized contactor C1 and the main valve H, or the energized contactor C2 and the main valve H. If it exists, the contact load of the main valve H and the contact contact load in an electricity supply contact can be suppressed low. Therefore, according to this embodiment provided with the energization contactors C1 and C2, it is possible to simplify a switching switch drive mechanism part. Moreover, the main valve H can also employ | adopt a vacuum valve excellent in the interruption | disconnection ability, ignoring an electricity supply capability, and also becomes higher reliability.

Furthermore, in 4th Embodiment, the switching switch which has a stable breaking capability can be obtained by suppressing the maximum value of the breaking current of the main valve H. As shown in FIG. In addition, in the state of FIG. 7C, even if a failure of the main valve H occurs, the circuit can be forcibly opened by the changeover switch S, and the current cutoff is enabled in the changeover switch S. FIG. There is an advantage.

(5) another embodiment

In addition, this invention is not limited to said embodiment, It is also possible to combine said embodiment suitably. Specifically, the embodiment shown in FIG. 9 and FIG. 10 combines the second and third embodiments.

In this embodiment, (A) the operating state, (B) the opening of the main valve H, (C) the operation of the switching switch S, and (D) the resistance valve W2 on the non-electrical tap 3 side. It becomes a switching process called a closed electrode, (E) the open electrode of the resistance valve W1 of the energization tap 2 side, and (F) the closed electrode of the main valve H.

According to this embodiment, the original effect of the above-mentioned 2nd and 3rd embodiment (to ensure the stable vacuum valve opening / closing operation which does not depend on a switching direction, and to suppress the maximum value of the interruption current in switching switch S). Compactness of the selector switch S].

In still another embodiment according to the present invention, as shown in Figs. 11 and 12, between the current limiting resistor R1 and the resistance valve W1, the current limiting resistor R2 and the resistance valve ( An overvoltage protector 100 such as a discharge gap or a nonlinear resistor may be inserted between W2).

If an overvoltage occurs between taps due to an external surge or the like, an excessive voltage is applied between the poles of the fixed contacts SA and SB of the switching switch S and the poles of the resistance valve W2. In this case, the resistance valve W2 breaks down and breaks down to the circuits of the movable contactor M2, the current limiting resistor R2, the resistance valve W2, the main valve H, and the movable contactor SC of the tap selector. The discharge current limited by the current limiting resistor R2 flows. If the discharge between the contacts of the resistance valve W2 occurs frequently, there is a problem that the contacts are easily damaged.

Therefore, according to the embodiment shown in FIG. 11 and FIG. 12, the limit voltage of the overvoltage protector 100 sets the interpolar breakdown voltage of the fixed contact SA and SB of the switching switch S, and the electrode of the resistance valve W2. By setting the value lower than the interval, the overvoltage protector 100 operates when the predetermined limit level is exceeded, and discharge at the contact point of the resistance valve W2 can be prevented.

According to the on-load tap-changing apparatus of the present invention, the main valve is opened when the valve for resistance on the tap side that is energized before the switching operation is closed and the valve for resistance on the tab side that is not energized before the switching operation is open. The maximum value of the breaking current can be reduced, and the consumption of the electrode contact of the main valve can be suppressed to stabilize the breaking capability.

Claims (6)

A valve for resistance and a current limiting resistor connected in series to each of the first movable contacts, between the first movable contacts and the neutral point, provided with two first movable contacts of the tap selector for selecting the tab of the tab winding. A switching switch comprising a plurality of fixed contacts provided respectively between the first movable contact and the current limiting resistor, a second movable contact for selecting one of the plurality of fixed contacts, and the switching switch. Connecting the main valve between the second movable contact and the neutral point, An on-load tap changer configured to open the main valve when the resistance valve on the tap side that is energized before the switching operation is a closed electrode and the resistance valve on the tap side that is not energized before the switching operation is an open electrode. Two first movable contacts of the tap selector for selecting the tabs of the tap windings are provided, and a current limiting resistor and a resistance valve connected in series to each of the first movable contacts are provided between the first movable contacts and the neutral point. A switching switch comprising a plurality of fixed contacts provided respectively between the first movable contact and the current limiting resistor, a second movable contact for selecting one of the plurality of fixed contacts, and the switching switch. Connect the main valve between the second movable contact and the neutral point, When the resistance valve on the tab side that is energized before the switching operation is a closed electrode, when the resistance valve on the tab side that is not energized before the switching operation is an open electrode, the main valve is opened, The second movable contact of the changeover switch in a state where the resistance valve on the tab side that is energized before the switching operation is closed after the main valve opens, and the resistance valve on the tab side that is not energized before the switching operation is open. Starts the operation, releases the electrical connection with the fixed contact which was in contact before the switching operation, And the resistance valve on the tab side not energized before the switching operation is closed after the electrical connection of the changeover switch is released. Two first movable contacts of the tap selector for selecting the tabs of the tap windings are provided, and a current limiting resistor and a resistance valve connected in series to each of the first movable contacts are provided between the first movable contacts and the neutral point. A changeover switch provided respectively between the first moveable contactor and the current limiting resistor, a changeover switch including a second moveable contactor for selecting one of the plurality of fixed contacts, and the second switch of the changeover switch; Connect the main valve between the movable contact and the neutral point, When the resistance valve on the tap side that is energized before the switching operation is a closed electrode, when the resistance valve on the tap side that is not energized before the switching operation is an open electrode, the main valve opens. After the main valve opens, the resistance valve on the tab side that does not conduct electricity before the switching operation closes, After the resistance valve on the tab side that is not energized before the switching operation closes, the resistance valve on the tab side that is energized before the switching operation opens. An on-load tap changer, characterized in that the main valve closes after the resistance valve on the tap side energized before switching operation. The on-load tap changer according to any one of claims 1 to 3, wherein the main valve and the resistance valve are constituted by a vacuum valve. The current carrying contact fixed contact is provided between two first movable contacts of a tap selector, and a current limiting resistor, respectively, The current carrying contact which can isolate | separate these live contact fixed contacts and a neutral point is provided. An on-load tap changer, characterized in that a contactor is connected to said neutral point. The on-load tap switching device according to any one of claims 1 to 3, wherein an overvoltage protector is connected between a connection point of the current limiting resistor and the resistance valve.

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