JPS6091608A - One tap type on-load tap changer - Google Patents

Abstract

PURPOSE:To contrive accomplishment of simplification and miniaturization of the structure of the titled tap changer by a method wherein a vacuum valve is arranged on the three equally divided parts of a circuit, a mounting stand whereon fixing shafts are fixed collectively, is provided and led out to outside using a lead-out terminal. CONSTITUTION:One valve system wherein one each of vacuum valve V, C, B 21 is used is adopted, the above is close-circuited in the normally operating state, a safest measure is taken for both external and internal lightings, and the vacuum valve 21 is fixed. A series-connected conductive contact point 18 is provided at a movable contact point, and it is mechanically interlocked with the movable contact point. A rolling movement is performed on the conductive contact point 18 by the rotation of the driving crank 17 provided at the center part of a change-over switch, a circular movement is converted into a linear movement, the movable contact point of the vacuum valve 21 is opened or closed, and a constitution is provided in such a manner that wasteful external force will be prevented from going to the vacuum valve 21. As a result, the constitution of the titled tap changer can be simplified and miniaturized.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a one-valve on-load tap changer that switches the taps of a transformer tap winding using a vacuum valve during load.

[Technical background of the invention and its problems]

It is well known that the cutting performance in a crystal vacuum is improved by an oil-submerged cut-off method that uses oil as an arc-extinguishing medium. It is applied to many technical fields including power circuit breakers.On-load tap changers are one of them, and especially when applied to transformers for electric arc furnaces, frequent tap changers, etc.
It has been put into practical use several years ago and is currently in operation because it can meet the demand for long life. By the way, the following technical issues arise when applying a vacuum valve to this on-load tap changer.

(11) If you simply replace the conventional oil disconnection contact with a vacuum valve, it is necessary to extend the mechanical life of the metal bellows used in multiple vacuum valves. The gap is small, which makes it weak against external and domestic demand, potentially leading to a short circuit between tags.

This needs to be prevented.

(2) Using a plurality of vacuum valves naturally complicates the opening/closing mechanism for opening and closing these valves.

Furthermore, the vacuum valve (- indicates that a metal bellows is used, and it is not true that this bellows controls the mechanical life of the vacuum valve.In order to extend the mechanical life of this bellows, the bellows C is stressed more than necessary. A highly reliable opening/closing mechanism that does not generate

(3) Monitoring the vacuum level of the Makabe valve is one of the important maintenance factors. Monitoring devices are required depending on the number of Makabe valves used, which becomes very expensive.

A number of proposals have been made in the past as methods for solving these technical problems. For example, in a resistance type LTC using three valves, an auxiliary switch is attached to solve the problem (1) so that no voltage is applied between the contacts of the Makabe valve, and when one valve is used, The problem in (1) is solved by closing the valve, but in contrast to (2) +: the vacuum valve itself is rotated to perform closing and opening operations.
The impact during closing and closing operations is applied directly to the metal bellows. Furthermore, since a voltage is applied when the vacuum valve is fixed and the oJ moving contact is opened, the container is made of porcelain. For this reason, it is weak against a shock loads during closing and opening, and there is a problem in terms of mechanical life.

[Purpose of the invention]

It is an object of the present invention to provide an l-valve member loading tap changer which solves the three technical problems mentioned above and has a simplified and compact configuration.

[Key points of invention]

The present invention employs an L-valve type using one vacuum valve, and the circuit is closed during normal operation.

The two vacuum valves are fixed, and the movable contact C2 is equipped with a series-connected current-carrying contact (movable), and the movable contact is mechanically interlocked with the current-carrying contact (C2).
= I movement) performs transfer operation by rotating the drive crank equipped with the sCC membrane at the center of the switching switch, and circular movement and linear movement (by converting between two, the true is opened and closed as a movable contact of the valve,
For this reason, the operation is smooth and unnecessary external force is eliminated.The vacuum valve C is double-layered.This configuration solves the three problems mentioned above.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to Figs. 1 to ↓.

Figure fi41 shows a circuit diagram of this embodiment. TW is the transformer tap winding, 'l'l, T2 is any tap of the tap winding. Ml and B2 are tap selectors connected to the taps of the tap winding, and Ml selects the odd-numbered side tap and B2 selects the even-numbered side tap. )IA, )IB These are energizing contacts exclusively for energizing provided within the tri switching switch. The movable contact of this current-carrying contact is connected in series with the movable-fixed contact of the vacuum valve VCB to form a current-carrying circuit.

It is connected. W is an auxiliary switch with 4 current limiting resistors, and the fixed contact A is 1(&(=, and B11L(B(:, each connected. Common contact CFi is connected to the current limiting resistor 几, then the neutral point (N) to form a circuit.The switching operation for this time is performed as follows.(a) The figure shows tap T1.
It shows the driving situation. The load current of the transformer flows to the neutral point through the tap winding TW, the tap 1'1, the tap selector M1, the energizing contact HA, and the vacuum valves V, C, and B, as indicated by the thick line in the figure. When the switching operation starts (as shown in Figure b1), the auxiliary switch W switches from A to B.

C between T2: A cross current flows through the current limiting resistor as shown by the dotted line. Next (the two vacuum valves V, C, and B open to cut off the load current and cross current. As a result, the load current flows as shown in the thick line of the tap T2111 in the figure (C). Then, as shown in the figure (d) The movable contact of the current-carrying contact moves at a predetermined speed.
2 @ current-carrying contact HB +: Close.

During this time, the load current flows through four current limiting resistors as shown by the thick line in the figure. Last +:, (f) I:A empty valve V as shown.

Name, B closes and the switching operation ends. A sequence diagram showing these switching orders is shown in FIG. 6C-2. To briefly explain FIG. 6, at time t, the rear auxiliary switch W switches from A to B, and then at t, the rear vacuum valves V, C, and B open. Subsequently, at t, the movable contact of the post-energization contact 1-IA starts moving. t, after-energization contact) 1e closes 1. Rear vacuum valve V, C
, B close, completing the switch to tap T2. The above explanation shows the switching order from tap T1 to T2, but tap T2
-The order of switching to T1 is that the auxiliary switch W is switched twice from B to human, and the other operations are exactly the same. The following two structures (explained in two parts. 1 are insulated drive shafts that rotate from a power source (not shown), 2 are insulated columns for supporting the entire switching switch breaker section, and 3 are supported by insulated columns 2 to store energy. 4 is a support that forms a mechanism. 4 is connected to an insulated drive shaft, and both ends are supported by the support 3. The guide bar is supported by the support 3. As shown in the figure, the hoisting plate performs reciprocating motion using a guide bar as a guide. 5 is a pressure The winding plate 36 (the second is the movable contact drive plate of the auxiliary switch W) It has a claw 36a connected to the connecting bottle (material) provided at 9 and a claw 36b connected as shown in FIG. .

Reference numeral 6 denotes a switching crank which operates in conjunction with the instantaneous operation of the energy storage case and transmits the power to the drive shaft 8. 7 is an insulating cylinder that supports the entire breaking section. The drive plate 9 is supported so as to be slidable on the drive shaft 8. The drive plate 9 is made of an insulating material, and holds movable contacts 13 and 13' at positions divided into three equal parts around the circumference for switching the fixed contacts 12A, 12B, and 12C arranged on the insulating cylinder 7. . The movable contacts 13 and 13' are supported by support pins 11 that pass through the drive plate 9.
and compression springs 10 and 1 that provide the contact pressure necessary for energization.
0'. Reference numerals 14 and 14' denote guide plates whose outer peripheries are fixed to the insulating tube 7 and bearings 16 and 16' provided in the center for allowing the drive shaft 8 to pass through and slide. Reference numerals 17 and 17' denote drive cranks fixed to the drive shaft 8, and are connected to movable energizing contacts 18 and 18' via pins. The inside of the insulating tube 7 is shown in FIGS. 3 and 4.

As shown in Figure 5, it is divided into three equal parts, with the auxiliary switch W in Figure 3 (2) and the vacuum valve V in Figure 4.
, C, B are also vacuum valves V, C, B in FIG.
A drive crank 17 and current-carrying contacts 18 for driving B
form each phase, making up three phases. Between the energizing movable contacts 18 and 18' is the groove 19 of the guide plate 14 and 14'.
, 19', and has a spring support η supported so as to be able to slide on the movable axis n of the central part (two vacuum valves 2). 3 gives the necessary contact pressure after compression by splashing.24
, 24' are flexible conductive bands for forming a series circuit with the current-carrying contacts 18, 18'. A groove provided in the 25fi town movement @n is slidably connected to a bottle provided in the spring support B, enabling the wiping action of the compression spring. 28 is a metal bellows, and 29 is a fixed shaft of the vacuum valve, which is fixed to a vacuum valve mounting base 31 which is fixed to a neutral point lead-out conductor band 15 whose one end is fixed to the insulating cylinder 7.

As shown in FIG. 4, the mounting base 31 has a surface divided into three equal parts of the circumference, and the vacuum valve 21 is fixedly mounted between these parts. Therefore, the mounting base 31 forms a neutral point on the circuit, and can be drawn out to the outside using the neutral point lead-out conductor 15. In addition, arranging the two vacuum valves 2 at equally spaced positions on the outer periphery of the mounting base 31 means that loads are applied from three directions at the input points of the vacuum valves 21 for each phase (at the two positions, loads are applied from three directions. are the same because they are given by the rotation of the common drive @8, so the sum of the acting forces in each three directions is zero.Therefore, the structure of the mounting base 31 is such that the vacuum valve 21 is mounted (= has the necessary surface). It has the advantage of being compact.
also has the role of a bearing that supports the rotation of the drive shaft 8.

The operation of the embodiment configured as described above is shown in FIG. 8(a).
This will be explained by (f). First, as shown in the figure (a), a heart motion operating mechanism (not shown) rotates in response to a tap change command, and the insulated drive shaft 1 rotates, at the same time an eccentric force is applied, and 4 rotates. As a result, the hoisting plate starts moving in the right direction (in the direction of the arrow) in the figure, and the claw 36a also moves the connecting bottle. Accordingly, the auxiliary switch drive plate 9 rotates clockwise and starts switching the attached movable contact 13 from the fixed contact A to B.The winding plate further moves and the claw 36b closes the catch 37b. When the movable contact 13 moves until it comes into contact with the fixed contact B, as shown in FIG.
(2) The accumulated energy is stored in the storage case and then the catch 3
7 Disengagement with b starts from 1:.

In response to this, the storage case A follows the hoisting plate A and starts moving.

This movement causes the switching crank 61. "c" through the drive shaft 8
IJA@Crank 17 rotates clockwise and current-carrying contact 18
The transfer operation is started. (c) As shown in the figure, first Ay valves V, C, and B open to cut off the current and the current-carrying contact 18 (
HA ) into a no-current state. Then, when the current-carrying contact 18, which is in a non-current state as shown in the dJ diagram, rolls again (as shown in the ei diagram), the current-carrying contact FLB side fixed contact (
Insert two. During this time, the load current flows through the current limiting resistor R, as explained in FIG.

The closing operation is completed with the last two vacuum valves V, e, and H being given the necessary contact pressure, and the switching from tap T1 to Tl is completed as shown in figure fl. When switching from tap T2 to Tl in the reverse direction, the direction of the reciprocating movement of the winding plate is reversed and the drive crank 17. ! Although the direction of rotation of the electric contact 18 is reversed, the switching order is exactly the same.

〔Effect of the invention〕

Although the circuit, structure, and operation of one embodiment have been described in detail above, the following effects are produced by implementing the present invention.

(1) Figure 1 (8) (a port = 1 as shown; constant transformer operating state g + 2 is vacuum) The tubes V, C, and S are closed and are connected to the outer and inner peaks. is not affected at all. There is no need for any auxiliary switch to maintain the control.

(2) Vacuum valve v, c, BC? n is fixed and 1
Even if it is a valve type, it can be opened and closed by moving only the movable shaft, as in normal use. In addition, since the opening/closing operation of the movable shaft is performed by the circular movement of the driving crank 17 and the current-carrying contact 18, smooth operation can be achieved and unnecessary photographing can be avoided with the metal bellows 2B+- of the vacuum valve.
Give power. Therefore, the life span of the metal bellows can be extended.

(3) Since only one vacuum level monitoring device for each vacuum valve is required, it can be simplified and manufactured at low cost. .

(4) Arrange the valve 2 on three equal parts of the circumference of the vacuum valve mounting base 31 (the force applied when the vacuum valve is turned on from the two acts simultaneously in three directions, so the vector sum of the points of action is It becomes 蓓.Therefore, jin, which becomes smaller, is formed.

(5) The mounting base 31 can be used as it is as a three-phase circuit (neutral point in the case of 2) (Note 1) as a bearing for the drive shaft 8, which can be used as it is as a single-phase device (connection terminal in the case of 2). It also has the same function. Therefore, the configuration of the switching switch can be made smaller and lighter.

[Brief explanation of drawings]

Figure 1 +t- (al~(fl is a circuit diagram showing the operating state of one embodiment of the present invention, Figure 2 is the same as Figure 3) I-)
Cross-sectional view taken along line I (2, Figure 3, Figure 4, Figure 5)
Figure 7 is the E-H cross section, G-G cross section, and F cross section in Figure 2, respectively.
6 is a time chart showing the operating state, and FIGS. 8(a) to 8(f) are diagrams illustrating the operation. TW...Tap winding TI, T,...Tap HA
, In... Current-carrying contact W... Auxiliary switch iL
...Current limiting resistor V, C, 13...Vacuum (valve 8...Drive shaft 15...Neutral point lead-out conductor 17...
・Drive crank 18... Current-carrying contact (movable)...
Sliding pin 21...Vacuum valve 7...Insulating tube
14, 14'... Guide plate 31... Mounting stand Agent Patent attorney Seisuke Norichika (and one other person) Figure 1 Figure 2 Figure 3 Figure 4 B Figure 6 Figure 7

Claims (1)

[Claims] In a 1-tap type on-load tap changer that performs tap switching using a tag of a transformer 2J tag winding using one current-limiting impedance, a current-carrying contact with l = t, and one vacuum valve, the vacuum valve is circularly switched. A mounting base is installed to fix the fixed shaft of each vacuum valve at the same time on the circumference (with two devices).
A one-tap type on-load tap changer characterized in that two connected draw-out terminals are provided so that the output can be drawn out to the outside.