JPS61133617A - On-load tap changer - Google Patents

Abstract

PURPOSE:To switch in a non-arc state by connecting a current limiting element between a preceding contact shoe and the first variable contact shoe, and by connecting a thyristor switch between a following contact shoe and the first variable contact shoe. CONSTITUTION:A current limiting element 7 is connected between a preceding contact shoe 33 and a welding contact shoe 31. A thyristor switch 8 is connected between following contact shoes 32 and 31. The switch 8 changes to ON before the contact shoe 31 gets off the first fixed contact shoe 32, and it changes to OFF before the contact shoe 32 gets off the contact shoe 21. And then, the contact shoe 31 is opened from the contact shoe 21 in a non-arc state, and the contact shoe 32 is opened from the contact shoe 21 in a non-arc state.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an on-load tap changer used in a transformer,
In particular, the present invention relates to a device that allows arc-free tap switching regardless of the switching direction.

[Prior art] -2 A tap switching device on load switches the taps of a transformer while current is flowing through it, and in devices with a small current switching capacity, the tap selection contactor that selects the tap changes the current. In many cases, a so-called load tap selector that also opens and closes the tap is used. In addition, a load tap selector is known that performs a switching operation without current interruption by using a thyristor switch in which l pairs of thyristors are connected in antiparallel. Therefore, the circuit configuration of this type of on-load tap switching device is shown in FIG. In the figure, (1) is the transformer winding, (lυ, (/J) is the voltage tap provided in the winding (1)K, and (2) is these voltage tap (//)I(/1)
With fixed contacts connected respectively to the transformer Kl! Multiple taps are provided depending on the number of taps required.
is the first fixed contact connected to the voltage tap (//) K,
(,22) is the first fixed contact connected to the voltage tap (l2) K adjacent to the first fixed contact (l), (3)
is a movable contact that contacts the fixed contact (2) and supplies current to the load side; (31) is a first movable contact that normally conducts the load current; (32);

(JJ) is a first movable contact and a third movable contact, which are cut on both sides of the first movable contact through which a load current temporarily flows during switching operation; Contact (
(32) is a thyristor switch formed by l pairs of thyristors connected in series and connected in antiparallel; (3) is a current limiting resistor which is a current limiting element connected in series with the third movable contact (33); (6) connects the first movable contact (3/) to the first and third movable contacts (32) and C33 via the silisk switch (S) and current limiting resistor (5), respectively. This connection is connected to the output terminal of the transformer, that is, the load side.

The on-load tap switching device configured as described above performs a voltage tap switching operation in the switching sequence shown in FIG. 3. Therefore, the switching operation from the voltage tap (11) to the voltage tap (l2) will be explained using FIGS. 1 and 3. The one in Figure 2 is in steady state, from transformer (1) to voltage tap (//
) → first fixed contact (col) → first movable contact (3
Current flows through the path from 1) to connection (6). In this state, the first movable contact (31) is connected to the first fixed contact (
C2) When the movable contact (J) is moved so that it makes contact with K, the first movable contact (32) and the first fixed contact (C1) meet at point (a) in Figure 3. The first movable contact (31) makes contact with the first fixed contact (31) at 11 points (b).
move away from

Next K, the third movable contact (33) contacts the first fixed contact (-1) at point (e), and the first movable contact (32) contacts the first fixed contact (-1) at point (e).
) separates from the first fixed contact (21) at point (1), and the first movable contact (Jt) contacts the first fixed contact (Jt) at point <6), At point (f), the third movable contact (JJ) separates from the first fixed contact (J).
), the first movable contact (3a) is located between the point (sL) and point (b) shown in Fig. After contacting the child (col), the first movable contact (31) turns 'ON' at point (g) until it separates from the first fixed contact (col),
Between point (e) and point ((to), that is, after the third movable contact (3J) contacts the first fixed contact (ko2),
The first movable contact (32) is the first fixed contact (col)
The current flow on the movable contact (3) side shows that the first movable contact (31) turns off at the point (day) until it leaves the first fixed contact (31). When disconnecting from l), a parallel electric path K, (l) → (32) → (su → (6)) is formed between the first movable contact (Jt) and the connection part (6). The first movable contact (31) can be separated from the first fixed contact (Jt) in an arc-free state.Also, the first movable contact (32) can be separated from the first fixed contact (Jt) in an arc-free state. When disconnecting from the contact, there is no current flowing through the first movable contact (contact 3), so it can be disconnected without arcing.

[Problem that the invention seeks to solve]

In the conventional on-load tap switching device as described above, tap switching from the voltage tap (11) to the voltage tap (/J) can be performed without arcing, but the tap switching from the voltage tap (l2) to the voltage tap ( In the tap change in the opposite direction to lυ, the first movable contact (31) separates from the first fixed contact (ko2) at the point in Fig. 3 (→, and the JQI movable contact (3J) The current is cut off at point (f) in Figure 3 where the switch leaves the first fixed contact (K2), and a cutoff arc is generated.In this way, if an arc occurs during the switching operation, it will cause damage to the surroundings. Contamination in the atmosphere not only reduces insulation ability and generates flammable gas, but also causes wear and tear on movable or fixed contacts, and current limiting resistance (RIK).
The amount of heat storage increases with the increase in current flow time, and K increases,
If the wear of each contact becomes severe and the position of point (C) in Figure 3 becomes the position of point (C/), switch from voltage tap (ll) to voltage tap (l2). Sometimes,
Thyristor switch (turn off at point (h) in Figure 3)
This can lead to an abnormal phenomenon in which the electrical circuit disappears when the line is turned off.As described above, in the conventional device, there was a problem in that live line switching, that is, tap switching, was effective only in the same direction.

The present invention has been made to solve these problems, and an object of the present invention is to provide an on-load tap switching device that allows arc-free tap switching regardless of the switching direction.

[Means for solving problems]

In the on-load tap switching device according to the present invention, of the first movable contact and the third movable contact on the movable contact side, the first movable contact and the third movable contact contact the next stage voltage tap during the switching operation, that is, the preceding contact A current limiting element is connected between the child and the first movable contact, and a thyristor switch is connected between the trailing contact and the first movable contact.

[Effect]

In this invention, since the connection of the current limiting element and the thyristor switch is switched according to the switching direction of the voltage tap, arc-free voltage tap switching can be performed in both directions.

〔Example〕

FIG. 1 shows an embodiment of the on-load tap changer according to the present invention, and the tth (pJ) is the variable contactor (, 7).
Figure t(B) is a diagram showing the circuit configuration in the case of switching operation from voltage tap (//) to voltage tap (l2). FIG. 2 is a diagram showing a circuit configuration. In both figures, (1)
-(3) and (6) are exactly the same as the conventional device shown in FIG. (ri) is a current limiting resistor which is a current limiting element with one end connected to the connection part (6) and the other end connected to the first movable auxiliary contact (91). Ct) was connected at one end to the connection part (6) and at the other end to the first movable auxiliary contact (92). This is a thyristor switch in which l pairs of thyristors are connected in antiparallel. Also, (10/) to (lO) are the first to da fixed auxiliary contacts, respectively, and during the voltage tap switching operation, the first or third fixed auxiliary contacts (10υ, (10J
) and the first movable auxiliary contact (9λ) are electrically connected, and the first or third fixed auxiliary contact (101), (any one of 10! The first movable auxiliary contact (91) is configured to be electrically connected to the first movable auxiliary contact (91).

Next, the operation will be explained. In Figure 1(A),
The first movable contact (31) is the first fixed contact (-l)
By connecting with transformer winding (1) → voltage tap (
A current is flowing in the path of //) → first fixed contact (col) → first movable contact (31) → connection part (6). To switch from this state to the next adjacent voltage tap (Col), first, as shown in the figure, the first movable auxiliary contact (
? ) and the second fixed auxiliary contact (10), and connect the first movable auxiliary contact (9J) and the first fixed auxiliary contact (10).
0/).

The rest of the switching operation can be carried out in the same manner as in the conventional case. At this time, the thyristor switch (Z) is turned "ON" before the first movable contact (31) leaves the first fixed contact (L), and the first movable contact (5, 2) is turned on. 1 OFF" before the movable contact (31) leaves the first fixed contact (col). By this, the first Ct) transformer winding (1) → voltage tap (11)
→First fixed contact (Col) →First movable contact (32
) → first fixed auxiliary contact (10/) → first movable auxiliary contact (92) → thyristor Ct) → connection part (6), so the first movable contact (31 ) can be separated from the first fixed contact (coll) without arcing. Furthermore, when the first movable contact (32) leaves the first fixed contact (Col), the thyristor switch CI) is OFF, so the current flows from the transformer winding (1) to Voltage tap (12) → first fixed contact (2) → third movable contact (33) → third fixed auxiliary contact (to3) → second fixed auxiliary contact (10) → first The electric current flows in the electric path from the movable auxiliary contact (91) to the current limiting resistor (ri) to the connection part (6), and the first movable contact (3λ) can be opened without arcing.

On the other hand, in FIG. 1(B), the first movable contact (
31) is connected to the first fixed contact (ko2), the transformer winding (1) → voltage tap (l2) → second fixed contact (ko2) → first movable contact (31) → Connection part (6) Current is flowing through the path. In order to switch from this state to the adjacent next stage voltage tap (11) (switching in the opposite direction to the above switching), first 1 movable auxiliary contact (q
t) is connected to the second fixed auxiliary contact (lO2), and the first movable auxiliary contact (9-) is connected to the third fixed auxiliary contact (to
Connect to e). All that is left to do is to perform the reverse operation of the switching operation described above. Furthermore, the thyristor switch (ff) is turned on before the first movable contact (31) is separated from the first fixed contact (22), and the third movable contact (33) 'OFF' before disconnecting from fixed contact (2J)
"If so, the first movable contact (31) and the third movable contact (33) will separate from the first fixed contact (-1) without arcing for the same reason as explained above. be able to.

In addition, in the said Example, the case where the current-limiting resistor was used as a current-limiting element was demonstrated, but you may use a nonlinear resistance element or a saturable reactor as a current-limiting element.

〔Effect of the invention〕

As described above, according to the present invention, on both sides of the movable contact for energization on the movable contact side of the on-load tap changer,
Of the two movable contacts installed in parallel with this that temporarily conduct load current during switching operation, the movable contact that precedes the adjacent voltage tap and the current-carrying contact during switching operation. By configuring a circuit in which a current limiting element is connected between the movable contacts and a thyristor switch is connected between the following movable contact and the energizing movable contact, the following effects can be obtained. It will be done.

(a) Switching without arcing is possible regardless of the direction of tap switching. fp) There is no wear and tear on each contact due to arcing.

Even if switching is performed frequently, the same switching operation as in the initial state can always be performed.

(c) The control of the thyristor switch is easy because it only requires the control of l pairs of antiparallel connected thyristors;
In addition, the ability of the element is sufficient as it has a short-time current carrying capacity (11>) to withstand the duty of being placed during switching operation.

Furthermore, by using a nonlinear resistance element or a saturable reactor as a current limiting element, slow switching becomes possible, which makes the control of the thyristor switch even easier, and also reduces the mechanism necessary for high-speed switching operation. and mechanical strength are no longer required, which leads to improved reliability.

[Brief explanation of drawings]

1(A) and 1(B) are circuit configuration diagrams showing one embodiment of the on-load tap switching device according to the present invention, and FIG. 1(A) shows the voltage tap (11) to the voltage tap (12).
Figure 1 CB) is a diagram showing the switching operation from the voltage tap (/J) to the voltage tap (tt'). Further, FIG. 1 is a circuit diagram of a conventional on-load tap switching device, and FIG. 3 is a diagram for explaining the operation of the on-load tap switching device of FIG. In the figure, (1) is the transformer winding, (2) is the fixed contact, (3) is the movable contact, (6) is the connection part, (7) is the current limiting resistor, (ff) is the thyristor switch, (ll Ha family (l
2) The first voltage tag, (12) is the first voltage tap, (2)
1) is the first fixed contact, (22) is the first fixed contact, (31) is the first movable contact, (32) is the first movable contact, and (33) is the third movable contact. It is a movable contact. In each figure, the same reference numerals indicate the same or corresponding parts. Figure 1 (A) Figure 1 Figure 2 Figure 3 Procedural amendment “Voluntary initiative” Showa year, month, day 60.3.12

Claims (3)

[Claims] (1) A first movable contact that contacts one of the voltage taps to supply current to the load in order to switch a plurality of voltage taps provided on the transformer winding; and this first movable contact. a second and a third movable contactor provided on both sides of the movable contactor, a contactor of the second and third movable contactor which moves in advance during the tap switching operation, and the first movable contactor. and a thyristor switch connected between the first movable contact and the contact that moves backward during tap switching operation. Tap changer on load. (2) The on-load tap switching device according to claim 1, wherein the current limiting element is a nonlinear resistance element. (3) The on-load tap switching device according to claim 1, wherein the current limiting element is a saturable reactor.