JPS61240518A - Loaded tap changer - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an on-load tap switching device using a thyristor as a current switching element.

[Conventional technology]

FIG. 3 is a circuit diagram of a conventional on-load tap switching device.

In the figure, (1) and (2) are transformer input terminals,
(3) is transformer 1. The next winding, (4) is the transformer secondary winding,
(5) is one voltage tap A of the transformer secondary winding (4),
Similarly, (6) is the other voltage tap B of the transformer secondary winding (4), and (7) to αQ are the thyristors Th, to Th4, respectively.
．． α◇ is the thyristor (7) and (
8) Thyristor switch A% (2) is thyristor switch B composed of thyristor (9) and QO connected in antiparallel, Q3 is thyristor switch A
(b) Movable contact, α4 is thyristor switch B (a)
The movable contact, αQ, is the current-carrying contact, α, which bypasses the thyristor switch Aαp and the thyristor switch B(2).
Q is linked to the current-carrying contact (C), and the current-carrying contact (G) is connected to the transformer 2.
Auxiliary contact that generates a signal when the voltage taps of the next winding (4) are not in contact, αη is thyristor + y), (g
), (9) and the ignition control device that controls the ignition of Moe, and α9 are transformer output terminals. In addition, if the current-carrying contact αQ is not in contact with any voltage tap,
The movable contact (to) and the movable contact α force are necessarily mechanically interlocked so that they contact different voltage taps.

Next, the operation will be explained. 4(a) to 4(h) explain the operation sequence of FIG. 3.

FIG. 4(a) shows a case where current is constantly taken out from voltage tag A(5), and the current is drawn from voltage tap A(5).
5) is supplied to the load (not shown) through the current-carrying contact αQ. At this time, the movable contact α and α force are the fourth
(a) In the figure, they are in an open state, but they may be in contact with voltage tap A (5), and thyristor switch A (6) and thyristor switch B (a) may be in a conductive or non-conductive state. It's okay.

In addition, Fig. 4(h) shows the case where current is constantly taken out from voltage tap B (6), and the current is passed from voltage type B (6) through current-carrying contact α to a load (not shown).
supplied to At this time, the movable contact (to) and the α force are in the released state as shown in Fig. 2 (h).
May be in contact with voltage type B (6), thyristor switch AQI) and thyrisk switch B (6)
may be conductive or non-conductive.

In this way, from voltage tap A (5) to voltage tap B (6
), first, the thyristor switch B@ is made non-conductive by the ignition control device αη, and as shown in FIG. 4(b), the movable contact 0 and the voltage tap B (6) are switched. Move the movable contact (l) to the voltage tap A
(5) Contact with. At this time, the current-carrying contact (a) is in contact with voltage tap A (5), so the current flows through voltage tap A.
(5) and is supplied to the load (not shown) through the current-carrying contact α. At this time, the thyristor switch A0])
It may be conductive or non-conductive. Next, as shown in FIG. 4(c), the movable contact σ field and the energized contact α field
Q contacts voltage tap A (5), and movable contact α contacts voltage tap B (6). At this time, the thyristor switch B (6) remains non-conductive due to the ignition control device α force, but the thyristor switch 8 θυ is controlled to be conductive. At this time, the current supplied to the load (not shown) is supplied from the voltage tap A(5) through the current-carrying contact α0. Next, as shown in FIG. 4(d), the current-carrying contact a
Q separates from the voltage tap A (5) and is not in contact with any tap, but the thyristor switch AOυ
is in a conductive state, so it is possible to disconnect the voltage tap A (5) at the energized contact 6 o'clock without firing.

At this time, the current supplied to the load (not shown) is supplied from the voltage tap A (5) through the movable contact 03 and the thyristor switch 8 αυ. In this state,
The auxiliary contact QIG sends a signal to the ignition control device αη,
The ignition control device αη receives this signal, controls the thyristor switch Aα and the thyristor switch B (6), and transfers the current tap from the current tap A (5) to the voltage tap B (6). This state is shown in FIG. 4(e). IX 4 (e
) In the figure, the sirisk switch AO◇ is non-conducting,
The thyristor switch B(2) is controlled by the ignition control device Q″t) to be conductive.The current flows through the voltage tap B(6), the movable contact Oa, and the thyristor switch Bα.
is supplied to a load (not shown) through.

Next, as shown in Fig. 4(f), the current-carrying contact α contacts the voltage tap B (6) 8, but since the thyristor switch Ba2 is already in the conducting state, there is no firing and the current-carrying contact α contacts the voltage tap B (6) 8. αO can be in contact with voltage tap B(6). Next, as shown in FIG. 4(g), the movable contact (to) separates from the voltage tap A (5). At this time, the current flows through the voltage tag B (6) and the current-carrying contact a5 to the load (
(not shown). Also, thyristor switch B
(2) may be in either a conductive or non-conductive state, but as shown in FIG.
A state is reached in which current is steadily drawn from (6), and the switching is completed.

As described above, in the conventional device, as shown in FIGS. 4(d) to 4(e), the current-carrying contact n5 is set as the timing condition for switching the current from tap A (5) to tap B (6). Since the moving auxiliary contact QQ is used, it becomes mechanically complicated, and at the same time, in order to minimize the heat generation of thyristor switch A (b) and thyristor switch B (6), the time during which current flows through the thyristor switch is minimized. However, even if you try to measure high-speed switching, accurate timing is not an advantage.Therefore, even though the switch uses a thyristor switch that is capable of high-speed switching, it is not possible to take advantage of it. However, there was a problem in that the heat dissipation device was large due to the large amount of heat generated.

[Summary of the invention]

This invention was made to solve the above-mentioned problems, and uses a current detection device to detect the presence or absence of current in a current-carrying contact. To provide an on-load tap switching device capable of high-speed switching by switching current to a thyristor switch.

[Embodiments of the invention]

In FIGS. 3 and 4 showing the conventional type, the contact state in which the current can be switched from voltage tap A (5) to voltage tap B (6) is clear from FIG. ) is in contact with voltage tap A (5), the movable contact α is in contact with voltage tap B (6), and the energizing contact is not in contact with any voltage tap. Now, the conventional method Fig. 2 (b
), (c), (f) and (g), thyrisk switch Aση or thyristor switch B(
b) When the energizing switch α is in contact with the same voltage tag, the forward voltage drop of the thyristor switch is about 1 to 2 V, so even if the thyristor switch is in a conductive state, most of the current is flows through the current-carrying contact (g). Therefore, between Figures 4(a) to 4(h),
Current does not flow through the current-carrying contacts) because (d) and (e
) only. The presence or absence of current in the current-carrying contact αυ is already detected, and if no current is detected, it may be considered that the state is in (d) or (e). This indicates that the switching timing can be determined by the presence or absence of current in the current-carrying contact instead of the auxiliary contact αQ mechanically interlocking with the current-carrying contact.

FIG. 1 shows an embodiment of the present invention. In the figure, (1
)~αυ, a7)~G9 are the same as the conventional ones, so their explanations will be omitted. (2) is a current detection device that detects the current flowing through the current-carrying contact αQ, and is, for example, a current transformer.

The tap switching operation in FIG. 1 will be explained with reference to FIGS. 2(a) to 2(h). In Figure 4, (4) to (6), α◇ to α
υ, αka.

■ is the same as in Figure 1.

FIG. 2(a) shows the case where current is constantly taken out from voltage tap A(5), and the current is drawn from voltage tap A(5).
5) through the current-carrying contact (2) to the load (not shown).
supplied to At this time, the movable contacts α→ and αY are in the open state in FIG. 2(a), but they may be in contact with the voltage tap A(5), and the movable contacts B(6) may be conductive or non-conductive.

In addition, Fig. 2 (h) shows the case where a steady current is taken out from the voltage tap B (6), and the current is passed from the voltage tap B (6) through the current-carrying contact α to the load (not shown). ). At this time, the movable contact (to) and α are in the released state in Fig. 2 (h), but
It may be in contact with voltage tap B (6), and thyristor switch A (11) and thyrisk switch B (
A) may be conductive or non-conductive.

Now, when switching the tag from voltage tap A (5) to voltage tap B (6), first switch the thyristor switch B (6).
is brought into a non-conducting state by the ignition control device α, and the second
(b) As shown in the figure, moveable contact α brown and voltage tap B (
6) and move the movable contact α to voltage tap A (5)
bring into contact with. At this time, the current-carrying contact αQ is in contact with the voltage tap A (5), so the current flows through the voltage tap A (5).
) is supplied to the load (not shown) through the current-carrying contact α→. The thyristor switch Aαη may be conductive or non-conductive at this time. Next, as shown in FIG. 2(c), the movable contact (to) and the current-carrying contact (t) contact voltage tap A (5), and the movable contact α (t) contacts voltage tap B (6). . At this time, the thyristor switch Aθ◇ is controlled to be conductive by the ignition control device α force. At this time, the current supplied to the load (not shown) is supplied from the voltage tap A (5) through the current-carrying contact (A). Next, as shown in FIG. 2(d), the movable contact (to) separates from the voltage tag A (5) and is in a state where it does not contact any tap, but the movable contact (to) is already in the state where it is not in contact with any tap.
11) is in a conductive state, so the current-carrying contact αQ can disconnect from the voltage tap A(5) without firing. At this time, the current supplied to the load (not shown) is supplied from the voltage tap A (5) through the movable contact α and the thyristor switch A (B). In this state, the current detection device sends a message to the ignition control device αη that no current is flowing through the current-carrying contact (G), and the ignition control device αη receives this signal and sets the silicate switch Aα◇ and Controlled by thyristor switch B (6), current is transferred from voltage tap A (5) to voltage tap B (6).

This state is shown in FIG. 2(e). In FIG. 2(e), the thyristor switch Aαυ is controlled by the ignition control device α so as to be non-conductive and the thyristor switch B(2) to be conductive. Current is supplied to a load (not shown) through voltage tap B (6), movable contact (b), and thyristor switch B (6).

Next, as shown in Fig. 2(f), the current-carrying contact αQ contacts the voltage tap B (6), but since the thyristor switch B (6) is already in the conductive state, the current is applied without firing. The contact (g) can be in contact with the voltage tap B (6). Next, as shown in FIG. 2(b), the movable contact α leaves the voltage tag A(5). At this time, the current is
It is supplied to a load (not shown) through voltage tap B (6) and current-carrying contact (A). Also, thyristor switch B (2
) may be in either a conductive state or a non-conductive state.

Next, as shown in FIG. 401), a state is reached in which current is steadily taken out from the voltage tap B(6), and the switching is completed.

〔Effect of the invention〕

As described above, according to the present invention, the switching timing of the thyristor switch is determined by the presence or absence of current in the current-carrying contact, so even if a series of switching and operations are performed at high speed, stable and reliable switching can be achieved. You get the timing.

That is, since it is possible to minimize the period of current flowing through the thyristor switch, the amount of heat generated by the thyristor switch is also reduced, and the device can be made smaller accordingly.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram showing the on-load tap switching device according to the present invention, Fig. 2 is an operation sequence diagram of Fig. 1, Fig. 3 is a circuit diagram showing the conventional one, and Fig. 4 is the operation of Fig. 3. It is a diagram. - Referring to the diagram, (5) is the first voltage tap, (6) is the second
voltage tap, (b) is the first thyrisk switch, (
6) is the second thyristor switch, αQ is the current-carrying contact, and σ
1 is the ignition control device, and ■ is the current detection device. Note that the same reference numerals in each figure indicate the same or corresponding parts.

Claims (1)

[Claims] A current-carrying contact in contact with a first voltage tap of a transformer having a plurality of voltage taps supplies current to the load, and a first voltage-carrying contact connected in parallel and anti-parallel with the current-carrying contact, respectively.
and a second thyristor switch, the thyristor switches are controlled by an ignition control device so as to switch the energizing contact from the first voltage tap to the second voltage tap, wherein the ignition control device Tap switching on load, characterized in that a current detection device is provided for detecting the current flowing through the current-carrying contact so as to switch the current supplied to the load from the first thyristor to the second thyristor when the current-carrying contact has no current. Device.