JPH0450726B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] This invention relates to an improvement in a load tap switching device using a semiconductor as a current switching element.

[Conventional technology]

FIG. 3 shows the configuration of a conventional on-load tap switching device. In the figure, the transformer tap winding 4 comprises a first fixed contact 5 and a second fixed contact 6. A first thyristor switch section 11 constructed by connecting thyristors 7 and 8 in antiparallel has one end connected to a first movable contact 13 and the other end connected to an output terminal section 18 . The second thyristor switch section 12, which is constructed by connecting the thyristors 9 and 10 in antiparallel, has one end connected to the second movable contact 14 and the other end connected to the output terminal section 18. Current-carrying movable contact 1
Reference numeral 5 designates bypass contacts of the first and second thyristor switch sections 11 and 12. Ignition control device 17
controls the firing of thyristors 7, 8, 9 and 10. The current detection device 20 is, for example, a current transformer for detecting the current flowing through the current-carrying movable contact 15, and its output signal is transmitted to the ignition control device 17 via a signal line 16. Note that connection lines between the ignition control device 17 and each thyristor 7, 8, 9, and 10 are not shown. FIG. 4 shows the operating sequence of this conventional example of a load tap switching device.

FIG. 4a shows a case where a current is constantly taken out from the first fixed contact 5, and the current flows from the first fixed contact 5 to the energizing movable contact 15 and the output terminal part 1.
8 and is supplied to a load (not shown). At this time, the first movable contact 13 and the second movable contact 14 are in a released state, but they may be in contact with the first fixed contact 5, and the first thyristor switch portion 11 and the second movable contact 14 may be in contact with the first fixed contact 5. The thyristor switch section 12 may be in either a conductive state or a non-conductive state.

When switching the tap from the first fixed contact 5 to the second fixed contact 6, first the second thyristor switch section 12 is brought into a non-conducting state by the ignition control device 17, and as shown in FIG. As shown in , the second movable contact 14 is moved to the second fixed contact 6,
The first movable contact 13 is brought into contact with the first fixed contact 5. At this time, since the energizing movable contact 15 is in contact with the first fixed contact 5, the current flows from the first fixed contact 5 to the energizing movable contact 15 and the output terminal section 18.
is supplied to the load through. The first thyristor switch section 11 may be either conductive or non-conductive at this time. Next, as shown in Figure 4c, the first
The movable contact 13 and the current-carrying movable contact 15 are in contact with the first fixed contact 5 , and the second movable contact 14 is in contact with the second fixed contact 6 . At this time, the ignition control device 1
7, the first thyristor switch section 11 is
It is controlled to be conductive.

Next, as shown in FIG. 4d, the movable contact 15 separates from the first fixed contact 5 and comes into contact with no tap, but the first thyristor switch section 11 has already become conductive. Therefore, the current-carrying contact 15 can detach from the first fixed contact 5 without firing. At this time, the current supplied to the load is supplied from the first fixed contact 5 through the first movable contact 13, the first thyristor switch section 11, and the output terminal section 18. In this state, the current detection device 20 detects that no current is flowing through the current-carrying movable contact 15 and sends the signal to the ignition control device 17, and the ignition control device 17 receives this signal and 1 thyristor switch section 11
is made non-conductive, the second thyristor switch portion 12 is made conductive, and the current path is transferred from the first fixed contact 5 to the second fixed contact 6. This state is the fourth
Shown in Figure e. The current flows through the second fixed contact 6, the second movable contact 14, and the second thyristor switch section 12.
and is supplied to the load through the output terminal section 18.

Next, as shown in FIG. 4f, the energizing movable contact 1
5 makes contact with the second fixed contact 6, but since the second thyristor switch portion 12 is already in a conductive state, it is possible to make contact with the second fixed contact 6 without firing. Next, as shown in Figure 4g, the first
The movable contact 13 leaves the first fixed contact 5 . At this time, the current is supplied to the load through the second fixed contact 6, the current-carrying movable contact 15, and the output terminal 18, and the second thyristor switch section 12 may be in either a conductive or non-conductive state.
Next, as shown in FIG. 4h, a state is reached in which current is constantly drawn from the second fixed contact 6, and the switching is completed. Conversely, switching from the second fixed contact 6 to the first fixed contact 5 is performed in the reverse order from the state shown in FIG. 4h to the state shown in FIG. 4a.

In addition, in the above-mentioned switching order, current transformer 2
The current does not flow through 0 in Figures 4d and 4e.
This is the only case in which tap switching is allowed.

[Problem that the invention seeks to solve]

As described above, in the conventional device, as shown in FIGS. 4d to 4e, in order to obtain a timing signal for switching the current from the first fixed contact 5 to the second fixed contact 6, Since it uses a current transformer 20 that detects the presence or absence of current flowing through the current-carrying movable contact 15, it is necessary to use a fairly large transformer due to insulation, especially when the potential difference between the tap winding and the ground side (ignition control device) is large. is required, which is disadvantageous in terms of structure and increases cost. In addition, it is susceptible to the effects of electromagnetic induction, requiring noise-proofing measures.

The present invention provides a device capable of obtaining a switching timing signal without using a current transformer in order to solve the above-mentioned problems.

[Means for solving problems]

The on-load tap switching device according to the present invention includes first and second light emitting elements connected in parallel to each of the first and second semiconductor switches for detecting the voltage applied to the semiconductor switch, First and second optical fibers are provided for transmitting optical signals emitted by the first and second light emitting elements to a photoelectric converter in the ignition control device.

[Effect]

When the semiconductor switch is in an open state, a light emitting element connected between both terminals of the semiconductor switch emits light. The light of the light-emitting element is transmitted to the ignition control device by an optical fiber, and converted into an electrical signal by a photoelectric converter therein, and the electric signal becomes a control input signal of the ignition control device.

〔Example〕

FIG. 1 shows an embodiment of the invention. In the figure, the transformer tap winding 4 comprises a first fixed contact 5 and a second fixed contact 6. The first thyristor switch section 11, which is a semiconductor switch configured by connecting the thyristors 7 and 8 in antiparallel, has one end connected to the first movable contact 13, and the other end connected to the output terminal section 18. . The second thyristor switch section 12, which is constructed by connecting the thyristors 9 and 10 in antiparallel, has one end connected to the second movable contact 14, and the other end connected to the output terminal section 18. The energizing movable contact 15 is connected to the first and second thyristor switch parts 11 and 12.
This is a bypass contact. For example, light emitting diodes (hereinafter referred to as LEDs) 21 and 22, which are light emitting elements connected in antiparallel, are connected in series with a current limiting resistor 25 to constitute a first voltage detection device 41, and are also connected in antiparallel. The LEDs 23 and 24 are connected in series with a current limiting resistor 26 to constitute a second voltage detection device 42. The first voltage detection device 41 is connected in parallel to the first thyristor switch section 11, and the second voltage detection device 42 is connected in parallel to the second thyristor switch section 12. each
LEDs 1 and 21 are connected to thyristors 1 and 21 so that the anode and cathode directions of the LEDs match the anode and cathode directions of the corresponding thyristors, respectively.
7, LED2 and 22 are thyristors 2 and 8,
LED3, 23 are thyristors 3, 9 and LED4, 2
4 has the same direction as the thyristors 4 and 10, respectively. Also, LED1, 21, LED2, 22,
The signals of LED3, 23, LED4, 24 are transmitted to the ignition control device 50 by optical fibers 27, 28, 29, 30, respectively. The ignition control device 50 has a built-in photoelectric converter (not shown),
The input optical signal is converted into an electrical signal. Wiring for controlling the ignition of the thyristor is not shown.

Next, the tap switching operation of this embodiment will be explained with reference to FIGS. 2a to 2h. FIG. 2a shows a case where current is constantly taken out from the first fixed contact 5, and the current is passed from the first fixed contact 5 through the current-carrying contact 15 and the output terminal section 18 to the load (not shown). omitted). At this time, the first movable contacts 13 and 14 are in a released state in FIG.
The second thyristor switch section 12 may be in either a conductive state or a non-conductive state.

When switching the tap from the first fixed contact 5 to the second fixed contact 6, first the second thyristor switch section 12 is brought into a non-conducting state by the ignition control device 50, as shown in FIG. 2b. , move the second movable contact 14 to the second fixed contact 6, and move the second movable contact 14 to the second fixed contact 6.
The movable contact 13 is brought into contact with the first fixed contact 5. At this time, since the energizing movable contact 15 is in contact with the first fixed contact 5 , current is supplied from the first fixed contact 5 to the load through the energizing movable contact 15 and the output terminal portion 18 . At this time, the first thyristor switch section 11 is ignited to be in a conductive state. Moreover, the first and second voltage detection devices 41,
42 is the first and second thyristor switch section 1
Since the voltage applied to 1 and 12 is zero, no detection signal is output.

Next, as shown in FIG. 2c, the energizing movable contact 15
is separated from the first fixed contact 5. (The second movable contact 14 also remains open.) At this time,
Since the first thyristor switch section 11 is fired, the energized movable contact 15 can be opened without firing. At this time, the current supplied to the load is supplied from the first fixed contact 5 through the first movable contact 13, the first thyristor switch section 11, and the output terminal section 18.

Next, as shown in FIG. 2d, the second movable contact 1
4 contacts the second fixed contact 6. At this time,
Since the first thyristor switch section 11 is ignited and the second thyristor switch 12 remains non-ignition, the current supplied to the load is transferred from the first fixed contact 5 to the first movable contact 13 to the first thyristor switch 12. It is supplied through the thyristor switch section 11 and the output terminal section 18. Further, since the voltage between the first fixed contact 5 and the second fixed contact 6 is applied between both terminals of the second thyristor switch section 12 and the second voltage detection device 42, the LEDs 3, 23 and Current flows through the LEDs 4 and 24 to emit light, and the optical signals are transmitted to the ignition control device 50 through optical fibers 29 and 30. Upon receiving this optical signal, the ignition control device 50 makes the first thyristor switch section 11 non-conductive, makes the second thyristor switch section 12 conductive, and transfers the current from the first fixed contact 5 to the second thyristor switch section 11. Transfer to fixed contact 6. This state is shown in FIG. 2e. In FIG. 2e, the first thyristor switch section 11 is non-conducting;
The second thyristor switch section 12 is controlled by an ignition control device 50 to be conductive. The current flows through the second fixed contact 6, the second movable contact 14,
Second thyristor switch section 12, output terminal section 1
8 to the load.

At this time, the voltage between both terminals of the second voltage detection device 42 becomes zero, and conversely, the voltage is applied between the terminals of the first voltage detection device 41, and the LEDs 1, 21 and
The ignition control device detects that the LEDs 2 and 22 are turned on and the first thyristor switch section 11 is extinguished and becomes non-conductive. If this happens, LED1, 2
1. If the LEDs 2 and 22 do not light up, it means that there is an abnormal situation, and some kind of protection can be taken.

Next, as shown in FIG. 2f, the first movable contact 1
3 separates from the first fixed contact 5 without firing.
Since the energizing movable contact 15 also remains open, the current flows to the second fixed contact 6, the second movable contact 14, the second thyristor switch section 12, as in FIG. 2e.
It is supplied to the load through the output terminal section 18. At this time, the first and second voltage detection devices 41, 42
The voltages applied between both terminals are both zero.

Next, as shown in FIG. 2g, the energizing movable contact 1
5 contacts the second fixed contact 6, but since the second thyristor switch portion 12 is already in a conductive state, it is possible to contact the second fixed contact 6 without firing. At this time, the current is supplied to the load through the second fixed contact 6, the current-carrying movable contact 15, and the output terminal section 18. Further, the second thyristor switch section 12 may be in either a conductive state or a non-conductive state. Next, as shown in FIG. 2h, the current is steadily drawn from the second fixed contact 6, and the switching is completed. Conversely, switching from the second fixed contact 6 to the first fixed contact 5 is performed in the order from FIG. 4h to FIG. 4a. just,
In this case, the first voltage detection device 41 operates first, and switching becomes possible at that time. In other words,
If the switching direction from the first fixed contact 5 to the second fixed contact 6 is defined as "up" and the opposite is defined as "down", then when switching to "up", the second voltage detection device 42, when switching to "lower", the switching timing is determined by the operation of the first voltage detection device 41. In addition, the energizing movable contact 15
The ignition start timing of the thyristor (the thyristor switch section 11 in the above description) connected to the movable contact that opens later than the above may be synchronized with the switching signal from the operating mechanism or the like. Similarly, the extinguishing timing of the thyristor on the movable contact side (the thyristor switch section 12 in the above explanation) that contacts another fixed contact earlier than the energized movable contact 15 is synchronized with the switching completion signal from the operating mechanism, etc. Good too. That is, as shown in the explanation of the operation, if the thyristor does not need to be fired or not, it is sufficient to decide on either one.

In the above embodiment, an anti-parallel connected thyristor was used as the current switching element, but it is also possible to use a triac, etc.
Other semiconductor switching devices may also be used.

Furthermore, since the voltage detection device uses a light emitting element such as an LED, its signal can be used to monitor the operation of the thyristor. Furthermore, if there is enough switching time, for example, LED2, 22 and LED4, 2
4 can be replaced with a diode or the like, and the switching timing can be obtained by the operation of LED1 and LED3. In this case, a confirmation time of half a cycle or more is required, but the cost can be reduced because the number of LEDs and optical fibers is reduced.

〔Effect of the invention〕

As described above, according to the present invention, the control signal of the ignition control device is obtained by the light emitting element activated by the voltage between the anode and cathode of the thyristor and the optical fiber that transmits the light, so that a current transformer is not required. At the same time, noise resistance is improved because it is not affected by electromagnetic induction.

[Brief explanation of the drawing]

Figure 1 is a circuit diagram of an embodiment of the invention, Figure 2a
1 to 3 are diagrams showing the order of operation of the embodiment shown in FIG. 1, FIG. 3 is a circuit diagram of the conventional example, and FIG. 4 is a diagram showing the order of operation of the conventional example. 4... Transformer tap winding, 5... First fixed contact, 6... Second fixed contact, 11... First thyristor switch section, 12... Second thyristor switch section, 13 ...First movable contact, 14...
... Second movable contact, 15 ... Current-carrying movable contact, 18
... Output terminal section, 27, 28, 29, 30 ... Optical fiber, 41 ... First voltage detection device, 42 ...
...Second voltage detection device, 50...Ignition control device.

Claims (1)

[Claims] 1. First and second fixed contacts connected to a transformer tap winding, contacting the second fixed contact after a predetermined period of time after being separated from the first fixed contact. an energized movable contact, an output terminal portion connected to the energized movable contact, a first movable contact that separates from the first fixed contact before the energized movable contact contacts the second fixed contact; a first semiconductor switch connected between the first movable contact and the output terminal section, and a second fixed contact between the time when the energized movable contact opens and the time when the first movable contact opens. a second movable contact in contact with the second movable contact, a second semiconductor switch connected between the second movable contact and the output terminal section, and an ignition control device for controlling the first and second semiconductor switches. In the on-load tap switching device, the switch is connected in parallel to the first and second semiconductor switches, and voltages applied to each of the first and second semiconductor switches are applied, and when the same applied voltage is present, an optical signal is generated. first and second light emitting elements for outputting light, and first and second light emitting elements for transmitting optical signals emitted by the light emitting elements to a photoelectric converter of the ignition control device and controlling the semiconductor switch using the optical signals. On-load tap switching device with optical fiber.