JP3698893B2 - 2 line switching semiconductor switch - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
In the present invention, when two power lines are received by the power system and power is supplied to the load on one of the two received lines and a power failure or voltage drop occurs due to an accident on this line, the other line is instantaneously The present invention relates to a two-line switching semiconductor switch that switches to a non-interruption on the load side.
[0002]
[Prior art]
FIG. 11 is a circuit diagram showing a conventional two-line switching semiconductor switch disclosed in, for example, the November 1997 issue of Electric Review (P77-P81). In the figure, A and B are the A system and B of the power system. System, L is a load, MC11 is a two-line switching semiconductor switch, 1a and 1b are thyristor elements, 2a and 2b are snubber capacitors, 3a and 3b are snubber resistors, 4a, 4b and 4c are electromagnetic waves for voltage detection Transformers for shape instruments, 8a and 8b are high-speed open-circuit switches, 15a and 15b are open / close controls for thyristor elements 1a and 1b and high-speed open-circuit switches 8a and 8b in accordance with the detection results of electromagnetic-type instrument transformers 4a, 4b and 4c. The control apparatus which performs is shown.
[0003]
Next, the operation will be described. When the thyristor element 1a and the high-speed open switch 8a are on and the thyristor element 1b and the high-speed open switch 8b are off and the power is supplied from the A system to the load L, for example, a three-phase short circuit occurs in the A system. The voltage detection output of the shape transformers 4a and 4c decreases. This is detected by the control devices 15a and 15b, and the thyristor element 1a and the high-speed opening switch 8a are turned off instantaneously, and the thyristor element 1b and the high-speed opening switch 8b are turned on so that there is no instantaneous interruption from the A system to the B system. The load L is switched to achieve uninterruptible power.
[0004]
[Problems to be solved by the invention]
Since the conventional two-line switching semiconductor switch is configured as described above, a snubber capacitor is connected from the B system in the event of a power outage without a short circuit accident in the A system (such as when the upper circuit breaker is opened). Since the load-type and power-side electromagnetic instrument transformers are charged via the power line, two lines cannot be switched without detecting a power failure, so the snubber capacitor capacity is minimized and the impedance is maximized. By connecting a dummy load (not shown) to the secondary side of the instrument transformer, it was necessary to be able to detect a voltage drop even when the load was unloaded.
[0005]
In addition, the thyristor element is destroyed by overvoltage due to series resonance between the excitation impedance of the snubber capacitor and the electromagnetic transformer, and the excitation impedance of the transformer on the load side. There was a point.
[0006]
The present invention has been made to solve the above-described problems, and a snubber capacitor and a snubber resistor having constant values that match the dynamic characteristics of a semiconductor (thyristor element) to be used can be used. In addition , an object is to obtain a two-line switching semiconductor switch that can be applied regardless of voltage detection means and load, and can suppress a surge voltage to ground from the power supply side and the load side. .
[0007]
[Means for Solving the Problems]
In view of the above object, the present invention is a two-line switching semiconductor switch that switches between two power systems in accordance with detection results from voltage detection means on the power source side and load side to achieve uninterruptible power on the load side. A large-capacity capacitor having a capacity of at least several tens of times that of the snubber capacitor connected in parallel to the switching means is connected in parallel to the power supply side and the load side of the semiconductor switch, and the large-capacity capacitor is connected in a star shape. A two-line switching semiconductor switch is characterized in that the neutral point of the star connection is directly grounded .
[0008]
The present invention also provides a two-line switching semiconductor switch characterized in that the switching means is composed of gate turn-off thyristor elements connected in reverse parallel.
[0009]
The present invention also provides a two-line switching semiconductor switch in which the voltage detecting means is configured by connecting a capacitor-type instrument transformer in parallel to the power supply side and the load side of the semiconductor switch, respectively.
[0011]
According to the present invention, there is provided a two-line switching semiconductor switch characterized in that the switching means comprises a thyristor element connected in reverse parallel, and a high-speed opening switch connected in parallel thereto.
[0012]
The present invention also provides a two-line switching semiconductor switch in which a high-speed opening switch is connected in parallel to the gate turn-off thyristor element connected in reverse parallel.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Embodiment 1 FIG.
Embodiment 1 of the present invention will be described below with reference to the drawings. FIG. 1 is a circuit diagram showing a two-line switching semiconductor switch according to an embodiment of the present invention. In FIG. 1, the same or corresponding parts as those of the conventional one are indicated by the same reference numerals. MC1 is a two-line switching semiconductor switch, 5a and 5b are control devices, and 6a, 6b and 6c are tens of times (for example, 50 times or more) of a snubber capacitor installed in a star connection on the power supply side and load side. A large-capacity capacitor having a capacity.
[0014]
The voltage detecting means is composed of electromagnetic instrument transformers 4a, 4b, 4c, and the switching means is composed of thyristor elements 1a, 1b.
[0015]
Next, the operation will be described. By installing the large-capacity capacitors 6a, 6b, 6c on the power supply side and the load side, even if a power failure without a short-circuit accident occurs in the A system, the load on the A system switch Since the voltage (less than 1/50 of the power supply voltage) appears in proportion to the capacity of the snubber capacitors 2a, 2b and the large-capacitance capacitors 6a, 6b, 6c on the power supply side and the power supply side, the voltage can be detected and desired. Two lines can be switched.
[0016]
By connecting the large-capacity capacitor, it is possible to prevent series resonance between the excitation impedance of the electromagnetic type instrument transformer and the load side transformer and the snubber capacitor.
[0017]
Embodiment 2. FIG.
FIG. 2 is a circuit diagram showing a two-line switching semiconductor switch according to another embodiment of the present invention. In FIG. 2, the same or corresponding parts as those in the above embodiment are indicated by the same reference numerals. MC2 is a two-line switching semiconductor switch, and 11a and 11b are gate turn-off thyristor elements.
[0018]
In this embodiment, since the gate turn-off thyristor elements 11a and 11b are used as the switching means of the semiconductor switch, the switching time can be reduced to ½ or less (1 cycle or less → 1/2 cycle or less). .
[0019]
Embodiment 3 FIG.
FIG. 3 is a circuit diagram showing a two-line switching semiconductor switch according to another embodiment of the present invention. In FIG. 3, the same or corresponding parts as those in the above embodiment are indicated by the same reference numerals. MC3 is a two-line switching semiconductor switch, and 7a, 7b, and 7c are capacitor-type instrument transformers.
[0020]
In this embodiment, capacitor-type instrument transformers 7a, 7b, and 7c are provided as voltage detection means on the power source side and the load side instead of the electromagnetic instrument transformer, so that they are installed on the power source side and the load side. Thus, an economically excellent two-line switching semiconductor switch in which the capacity of the large-capacitance capacitors 6a, 6b, 6c is reduced can be obtained.
[0021]
FIG. 4 shows a circuit diagram of a two-line switching semiconductor switch MC4 in which the present embodiment is implemented using the gate turn-off thyristor elements 11a and 11b of the second embodiment. In this case, the same effect can be obtained.
[0022]
Embodiment 4 FIG.
FIG. 5 is a circuit diagram showing a two-line switching semiconductor switch according to another embodiment of the present invention. In FIG. 5, the same or corresponding parts as those in the above embodiment are indicated by the same reference numerals. MC5 is a two-line switching semiconductor switch.
[0023]
In the first embodiment, the case where a large-capacity capacitor having, for example, 50 times or more the capacity of a snubber capacitor is installed in a star connection on the power supply side and the load side has been described. However, as shown in FIG. Since the neutral points of the capacitive capacitors 6a, 6b, 6c are grounded, it is possible to suppress the surge voltage between the power supply side and the load side, and it is possible to suppress the surge voltage to the ground, and the highly reliable semiconductor switch for two-line switching Can be obtained.
[0024]
6 is a circuit diagram of a two-line switching semiconductor switch MC6 in which the present embodiment is implemented using the gate turn-off thyristor elements 11a and 11b of the second embodiment, and FIG. 7 is a circuit diagram of the third embodiment. FIG. 8 is a circuit diagram of a two-line switching semiconductor switch MC7 in which the present embodiment is implemented using capacitor-type instrument transformers 7a, 7b and 7c, and FIG. 8 shows the second embodiment shown in FIG. A circuit diagram of a two-line switching semiconductor switch MC8 embodying the present embodiment using the gate turn-off thyristor elements 11a, 11b and the capacitor-type instrument transformers 7a, 7b, 7c of the third embodiment is shown. . Even in this case, the same effect can be obtained.
[0025]
Embodiment 5 FIG.
FIG. 9 is a circuit diagram showing a two-line switching semiconductor switch according to another embodiment of the present invention. In FIG. 9, parts that are the same as or equivalent to those in the above embodiment are denoted by the same reference numerals. MC9 is a two-line switching semiconductor switch, 8a and 8b are high-speed opening switches, and 15a and 15b are control devices.
[0026]
The voltage detecting means is constituted by electromagnetic type instrument transformers 4a, 4b, 4c, and the opening / closing means is constituted by thyristor elements 1a, 1b and high-speed opening switches 8a, 8b.
[0027]
In the first embodiment, the case where a thyristor element is used as the switching element of the semiconductor switch has been described. However, as shown in FIG. 9, high-speed opening switches 8a and 8b are connected in parallel to the thyristor elements 1a and 1b. With this configuration, the energization period of the thyristor elements 1a and 1b is limited to about 3 cycles when the semiconductor switch is on and less than 1 cycle when the semiconductor switch is off, and the high-speed opening switches 8a and 8b are energized during other periods. Therefore, it is possible to obtain a compact two-line switching semiconductor switch MC9 that has low loss and does not require a cooling means (not shown) for the thyristor elements 1a and 1b.
[0028]
FIG. 10 shows a circuit diagram of a two-line switching semiconductor switch MC10 in which the present embodiment is implemented using the gate turn-off thyristor elements 11a and 11b of the second embodiment. Even in this case, the same effect can be obtained.
[0029]
Further, the present invention is not limited to the above-described embodiments, and it is needless to say that a desired combination of the embodiments is possible as necessary.
[0030]
【The invention's effect】
As described above, in the present invention,
A two-line switching semiconductor switch that switches between and connects two power systems in accordance with detection results from voltage detection means on the power supply side and load side to achieve uninterruptible power on the load side, and is a snubber connected in parallel to the switching means A large-capacity capacitor having a capacity at least several tens of times that of the capacitor is connected in parallel to the power supply side and load side of the semiconductor switch, and the large-capacity capacitor is used as a star connection, and the neutral point of the star connection is directly Since it is a two-line switching semiconductor switch characterized by being grounded , the snubber capacitor and snubber resistor can be used in accordance with the dynamic characteristics of the semiconductor using the snubber constant of the semiconductor switch, and the voltage detection means , applicable irrespective of the load, further power supply side and the ground between the surge voltage semiconductor switch for two-line switch that can suppress from the load side is obtained, et al. There is that effect.
[0031]
Further, since the opening / closing means is composed of gate turn-off thyristor elements connected in reverse parallel, the switching time can be reduced to ½ or less (1 cycle or less → 1/2 cycle or less), and quick switching is possible. Become.
[0032]
In addition, since the voltage detecting means is configured by connecting a capacitor-type instrument transformer in parallel to the power supply side and the load side of the semiconductor switch, respectively, the capacity of the large-capacitance capacitors installed on the power supply side and the load side can be reduced. .
[0034]
Further, since the switching means is constituted by connecting a thyristor element or a gate turn-off thyristor element in antiparallel and further connecting a high speed opening switch in parallel thereto, the energization period of the thyristor element is set to 3 cycles when the semiconductor switch is turned on. It is limited to less than 1 cycle when off, and it can be energized with a high-speed open-circuit switch during this period, so it has low loss and does not require a cooling means for thyristor elements, making the two-line switching semiconductor switch compact. Can be.
[Brief description of the drawings]
FIG. 1 is a circuit diagram showing a two-line switching semiconductor switch according to Embodiment 1 of the present invention;
FIG. 2 is a circuit diagram showing a two-line switching semiconductor switch according to Embodiment 2 of the present invention;
FIG. 3 is a circuit diagram showing a two-line switching semiconductor switch according to Embodiment 3 of the present invention;
FIG. 4 is a circuit diagram showing another two-line switching semiconductor switch according to Embodiment 3 of the present invention;
FIG. 5 is a circuit diagram showing a two-line switching semiconductor switch according to Embodiment 4 of the present invention;
FIG. 6 is a circuit diagram showing another two-line switching semiconductor switch according to Embodiment 4 of the present invention;
FIG. 7 is a circuit diagram showing still another two-line switching semiconductor switch according to Embodiment 4 of the present invention;
FIG. 8 is a circuit diagram showing still another two-line switching semiconductor switch according to Embodiment 4 of the present invention;
FIG. 9 is a circuit diagram showing a two-line switching semiconductor switch according to Embodiment 5 of the present invention;
FIG. 10 is a circuit diagram showing another two-line switching semiconductor switch according to Embodiment 5 of the present invention;
FIG. 11 is a circuit diagram showing a conventional two-line switching semiconductor switch.
[Explanation of symbols]
1a, 1b Thyristor element, 2a, 2b Snubber capacitor, 3a, 3b Snubber resistor, 4a, 4b, 4c Electromagnetic transformer, 5a, 5b, 15a, 15b Controller, 6a, 6b, 6c Large capacity capacitor 7a, 7b, 7c Capacitor-type instrument transformer, 8a, 8b High-speed opening switch, 11a, 11b Gate turn-off thyristor element.

Claims (5)

A two-line switching semiconductor switch that switches between and connects two power systems in accordance with detection results from voltage detection means on the power supply side and load side to achieve uninterruptible power on the load side, and is a snubber connected in parallel to the switching means A large-capacity capacitor having a capacity at least several tens of times that of the capacitor is connected in parallel to the power supply side and load side of the semiconductor switch, and the large-capacity capacitor is used as a star connection, and the neutral point of the star connection is directly A two-line switching semiconductor switch characterized by being grounded .   2. The two-line switching semiconductor switch according to claim 1, wherein the switching means is composed of gate turn-off thyristor elements connected in reverse parallel.   3. A two-line switching semiconductor switch according to claim 1, wherein said voltage detecting means is constituted by a capacitor-type instrument transformer connected in parallel to each of a power source side and a load side of the semiconductor switch. . 4. The two-line switching semiconductor switch according to claim 1 , wherein the switching means comprises a thyristor element connected in reverse parallel and a high-speed opening switch connected in parallel thereto.   3. The two-line switching semiconductor switch according to claim 2, wherein a high-speed opening switch is connected in parallel to the gate turn-off thyristor element connected in reverse parallel.

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