JPH08105948A - Zero mistake current breakage testing circuit - Google Patents

Abstract

PURPOSE: To provide a zero mistake current breakage testing circuit capable of supplying an AC current without having a zero point for a specified time to a sample switching device using a relatively compact facility and easy control sequence. CONSTITUTION: A device is provided with a capacitor 2 to supply an AC current to a sample switching device 1, and a first reactor 4 and a first opening switch 3 inserted between the capacitor 2 and the sample switching device 1. It is also provided with a second opening switch 6 connected in parallel to a serial circuit comprising the sample switching device 1 and the first reactor 4, a second reactor 5 connected serially with the second opening switch 6 to supply a larger DC component than the amplitude of the AC current to the sample switching device 1, and a current breakage point setting means 7 to give a zero point to a current at the sample switching device 1 at a specified time after charging of the second opening switch 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a current interruption test circuit for conducting a interruption test of a UHV switchgear or a circuit breaker applied to a high voltage system, and particularly using a relatively small equipment and an easy control sequence. A zero error that can supply a current such that the supply current does not reach the zero point for several tens to 100 ms after the current to be interrupted is supplied and the amplitude of the alternating current exists to the switchgear under test. The present invention relates to a current interruption test circuit.

[0002]

2. Description of the Related Art Generally, 1000 kV called UHV
In a high-voltage and ultra-high-voltage AC system, the resistance of the line is small.Therefore, depending on the accident and the sequence of accident processing, a DC component of a large current that greatly exceeds the AC amplitude of the AC current may be superimposed. is assumed.

In this case, for example, as described on page 1467 of "The 6th Annual Conference of the Institute of Electrical Engineers of Japan", the zero-miss phenomenon due to the superimposed current of the direct current component (the switching device applied to the alternating current system is The zero point of the current that can interrupt the current is the number 1
Do not visit for about 0 to 100 ms) occurs. Therefore, in order to confirm the soundness of the switching function of the switchgear under the above conditions even in the disconnection obligation verification test of the switchgear,
A superimposed supply of direct current for a relatively long time is required.

FIG. 9 shows an example of a conventional zero-miss current interruption test circuit, attached to page 86 of "JEC2300 Annex, AC Circuit Breaker" (The Institute of Electrical Engineers of Japan, Standards Committee of Electrical Standards, 1985, Denki Shoin). FIG. 17 is a circuit diagram showing a current source circuit side of the synthesis test circuit shown in FIG. 16.

In the figure, G is an alternator, Sp is a switchgear connected between both ends of the alternator G, S1 is a protection switch connected to the output terminal of the alternator G, and S2.
Is a closing switch connected in series with the protection switch S1, L
1 is a current adjusting inductance connected in series to the closing switch S2, Sh is an auxiliary switching device connected in series between the current adjusting inductance L1 and the test switching device Sp,
C1 is a recovery voltage superimposing capacitor connected between both ends of the test switchgear Sp and auxiliary switchgear Sh, and RI is connected between both ends of the test switchgear Sp and auxiliary switchgear Sh to superimpose a steep current. Arc extension circuit for i,
p is an alternating current flowing through the current source circuit and the test switching device Sp. Although not shown, an ultra-high voltage source circuit is connected between both ends of the test switchgear Sp.

Next, the operation of the conventional zero-miss current interruption test circuit shown in FIG. 9 will be described with reference to the current waveform diagram of FIG. Using the current source circuit shown in FIG.
In order to supply the alternating current ip superimposed with the direct current component to the switchgear under test Sp, first, with the voltage phase angle of the AC generator G at zero degree, the protection switch S1 and the closing switch S2.
Input.

In this case, as shown in FIG. 10, the test switchgear Sp is supplied with an alternating current ip in which a direct current component C equal to the alternating current amplitude A / 2 is superimposed. DC component C of AC current ip
Is attenuated like C ′ with the passage of time according to the decay time constant determined by the resistance of the current source circuit. Therefore, the AC current ip supplied to the switchgear under test Sp is D and E.
As described above, the zero point of the alternating current ip reaches the maximum after one cycle of alternating current.

In general, the switchgear Sp may cut off the AC current ip when the AC current ip reaches a zero point.
Particularly in the synthesis test circuit, the alternating current ip is easily cut off at the zero point of the alternating current ip where the voltage source is not applied. However, if the gradient of the alternating current ip at the zero point is made steep, the switchgear will not be interrupted. As a result, the operation is substantially the same as when the zero-miss current is superposed.

In the conventional breaking test circuit, an arc extension circuit RI is connected in parallel to the test switchgear Sp in order to make the gradient at the zero point steep so that the test switchgear Sp does not interrupt the alternating current ip. By doing so, a current having a steep gradient is superimposed at the zero point. In this case, for example, 100 ms for 50 Hz commercial AC (cycle 20 ms)
Considering the current supply of a certain degree, the zero point occurs twice in one cycle of the alternating current, so that it is necessary to superimpose the current 8 to 10 times.

[0010]

As described above, the conventional zero-miss current interruption test circuit includes a large number of large parts such as the arc extension circuit RI as equipment for supplying a DC component current superimposed on the AC current ip. Since it is necessary, an enormous amount of facilities are required, and there is a problem that it is impossible to realize downsizing and cost reduction.

Further, in accordance with the zero point timing, 100
Since a steep gradient current is superimposed about 10 times in ms, the control sequence for the test becomes complicated, and a lot of labor is required, and the efficiency of the test is adversely affected. There was a point.

The present invention has been made to solve the above-mentioned problems, and uses a relatively small-sized equipment and an easy control sequence to generate an alternating current that does not reach the zero point for several tens to 100 ms. The purpose is to obtain a zero-miss current interruption test circuit that can be supplied to the switchgear under test.

[0013]

A zero-miss current interruption test circuit according to claim 1 of the present invention includes a capacitor for supplying an alternating current to a device under test and a capacitor between the capacitor and the device under test. The first reactor inserted, the first opening / closing switch inserted between the capacitor and the test opening / closing device, and the second opening / closing switch connected in parallel to the series circuit including the test opening / closing device and the first reactor. An open / close switch, a second reactor connected in series with the second open / close switch to supply a direct current component having a larger amplitude than the AC current to the test open / close device, and a predetermined time has elapsed since the second open / close switch was turned on. It is provided with a current interruption point setting means for giving a zero point to the current of the switchgear under test later.

According to a second aspect of the present invention, in the zero-miss current interruption test circuit according to the first aspect, the current interruption point setting means is connected in parallel to the DUT and the discharge gap is connected in series to the discharge gap. The circuit includes a voltage source circuit including the transient oscillation circuit described above, and a timer circuit that conducts the discharge gap after a lapse of a predetermined time from turning on of the second opening / closing switch.

According to a third aspect of the present invention, there is provided a zero-miss current interruption test circuit according to the first or second aspect.
The current interruption point setting means includes a timer circuit that opens the second opening / closing switch after a predetermined time has elapsed since the second opening / closing switch was turned on.

According to a fourth aspect of the present invention, in the zero-miss current interruption test circuit according to any one of the first to third aspects, the current interruption point setting means is connected in series to the DUT. It includes a resistor.

In the zero-miss current interruption test circuit according to claim 5 of the present invention, in any one of claims 1 to 4, the current interruption point setting means is connected in parallel to the first reactor. The third reactor includes a third reactor, a third opening / closing switch connected in series to the third reactor, and a timer circuit that opens the third opening / closing switch after a lapse of a predetermined time from turning on of the second opening / closing switch.

[0018]

According to the first aspect of the present invention, the second opening / closing switch and the second reactor are connected to the test opening / closing device connected to the AC power supply capacitor via the first opening / closing switch and the first reactor. They are connected in parallel and a zero point is given to the supply current of the test opening / closing device after a lapse of a predetermined time from turning on of the second opening / closing switch. As a result, several tens to 10 ms
A current having an amplitude of alternating current is supplied to the switchgear under test without reaching a zero point for an arbitrary set period of 0 ms, and a zero-miss current is superimposed so that the switchgear under test does not interrupt the alternating current. Large equipment is unnecessary, relatively small equipment is used, and the control sequence is simplified.

Further, according to a second aspect of the present invention, a voltage source circuit having a conventional structure including a discharge gap connected in parallel to the DUT is used as the current breaking point setting means, and the second opening / closing switch is turned on. By using a timer circuit that conducts the discharge gap after a lapse of a predetermined time, a period during which the zero point of the alternating current does not reach is arbitrarily set, and the control sequence is simplified by a relatively small-sized facility.

Further, according to a third aspect of the present invention, a timer circuit for opening the second opening / closing switch after a predetermined time has elapsed from the closing of the second opening / closing switch is used as the current breaking point setting means, and the zero point of the AC current is used. The period during which the temperature does not reach is set arbitrarily, and the control sequence is simplified with a relatively small facility.

Further, according to a fourth aspect of the present invention, a resistor connected in series to the DUT is used as the current breaking point setting means, and the decay time of the zero miss current is set according to the resistance value of the resistor. By setting, the period during which the zero point of the alternating current does not reach is set arbitrarily, and the control sequence is simplified with a relatively small-sized facility.

Further, according to a fifth aspect of the present invention, a third reactor connected in parallel with the first reactor and a third opening / closing switch connected in series with the third reactor are provided as current breaking point setting means. And a timer circuit that opens the third opening / closing switch after a lapse of a predetermined time from the turning on of the second opening / closing switch, the period during which the zero point of the alternating current does not reach is arbitrarily set, and the control is performed by a relatively small-sized facility. Simplify the sequence.

[0023]

【Example】

Example 1. Embodiment 1 of the present invention will be described below with reference to the drawings. 1 is a circuit diagram showing a first embodiment of the present invention.
In the figure, 1 is a switchgear under test, 2 is a capacitor which is connected between both ends of the switchgear under test 1 and serves as a source of alternating current, and 3 is inserted between the capacitor 2 and the switchgear under test 1. First opening / closing switch (hereinafter referred to as closing switch)
Is.

Reference numeral 4 denotes a first reactor (hereinafter, simply referred to as a reactor) inserted between the capacitor 2 and the device under test 1, and a current that resonates with the capacitor 2 when the closing switch 3 is turned on and vibrates. It is given to the test switching device 1.

Reference numeral 5 denotes a second reactor (hereinafter, simply referred to as a reactor) connected in parallel to a series circuit composed of the test switchgear 1 and the reactor 4, and has an inductance value smaller than that of the reactor 4. 6 is reactor 5
Is a second opening / closing switch (hereinafter referred to as a closing switch) connected in series with the reactor 5. When the closing switch 6 is closed, the reactor 5 is connected to the test opening / closing device 1.

Reference numeral 7 denotes a voltage source circuit similar to the conventional circuit connected between both ends of the test switchgear 1, and a current cutoff point setting means for generating a current cutoff point (zero point) for the test switchgear 1. And is composed of the following 8 to 11 elements.

Reference numeral 8 is a power supply capacitor connected between both ends of the test switchgear 1, 9 is a discharge gap inserted between the test switchgear 1 and the power supply capacitor 8, and 10 is a series connection to the discharge gap 9. A reactor, 11 is a transient vibration circuit 11 including a series circuit of a resistor and a capacitor connected in parallel to the DUT 1.

Although not shown, a known timer circuit for conducting the discharge gap 9 is provided after a predetermined time (for example, about 80 ms) has elapsed after the closing switch 6 was turned on.

Next, referring to the waveform diagram of FIG.
The operation of the first embodiment of the present invention shown in FIG.
First, it is assumed that the capacitor 2 has been previously charged by a power source (not shown). Here, the closing switch 3
When is turned on, the electric charge charged in the capacitor 2 flows into the DUT 1 via the reactor 4, and the alternating current at this time draws a sine wave.

Next, when the closing switch 6 is turned on at the peak time of the sine wave alternating current i1, the alternating current i5 flowing through the closing switch 6 into the reactor 5 becomes the alternating current i.
AC amplitude of 5 (greater than the amplitude of AC current i1)
A DC component of the same size as is superimposed.

On the other hand, since the AC current i passing through the closing switch 3 does not include a DC component, the AC current i1 flowing through the DUT 1 is equal to the DC component of the AC current i5 flowing through the reactor 5. The direct current component (about -6000 A) is superimposed and supplied as shown in FIG.

The AC current i1 passes through the DUT 1 while being attenuated by a resistance value specific to the current source circuit. However, since the resistance value of the DUT 1 is almost 0, the resistance of the current source circuit is reduced. Since the value is very small, the damping time constant of the direct current component of the alternating current i1 is very long. Therefore, the direct current component of the alternating current i1 is hardly attenuated as shown in FIG. 2 and is substantially constant regardless of the passage of time.

The switchgear 1 under test can interrupt the alternating current i1 only at the zero point of the alternating current i1, but if the direct current component is larger than the amplitude of the alternating current component and has no zero point as shown in FIG. i1 cannot be blocked. Therefore, the AC current i1 having an AC amplitude is supplied for a predetermined time (several 10 ms to 100 ms) from the closing of the closing switch 6 to the operation of the timer circuit.

Hereinafter, when the discharge gap 9 in the voltage source circuit 7 becomes conductive due to the operation of the timer circuit after a lapse of a predetermined time (several 10 ms to 100 ms) after the supply of the alternating current i1, it is determined by the capacitor 8 and the reactor 10. Although an oscillating current is generated, this oscillating current does not flow into the transient oscillating circuit 11, but flows into the DUT 1 having the lowest impedance.

Since the current flowing through the test switchgear 1 is the sum of the above currents, the oscillating current flowing from the capacitor 8 in the voltage source circuit 7 through the reactor 10 after the discharge gap 9 is turned on causes the current as shown in FIG. In addition, the AC current i1 flowing through the DUT 1 becomes zero (i1 = 0) about 100 ms after the closing switch 6 is turned on.

Therefore, the voltage source circuit 7 generates the alternating current i
A zero point of 1 is generated, so that the switchgear under test 1 shuts off the alternating current i1. At this time, the generation timing of the zero point (superimposition period of the zero miss current) can be arbitrarily set by selecting various circuit constants including the timer circuit and the voltage source circuit 7. After that, the voltage applied to the transient vibration circuit 11 is applied to the test switching device 1, and the breaking test of the test switching device 1 is established.

As described above, by turning on the closing switch 6 when the capacitor 2 is turned on, only by connecting the reactor 5 in parallel to the test opening / closing device 1, a direct current component (zero miss current) of a large current is superimposed. The alternating current i1 can be supplied. After that, only after the predetermined time has passed, the discharge gap 9 is made conductive, the zero point is given to the alternating current i1, and the alternating current i1 can be cut off by the test switchgear 1. Therefore, the control sequence of the entire circuit is simplified and the equipment is downsized.

Example 2. In the first embodiment, the voltage source circuit 7 is exclusively used as the high voltage source, and the current breaking point setting means is connected to the discharge gap 9 and the discharge gap 9 that are conducted after a predetermined time has elapsed since the closing switch 6 was turned on. Although the voltage source circuit 7 including the charged capacitor 8 and the reactor 10 is used, a large-capacity capacitor that generates a high voltage is used as the capacitor 2, the voltage source circuit 7 is omitted, and the current cut-off point setting circuit is A large-capacity closing switch that is connected to the reactor 5 in series and is opened after a predetermined time has passed may be used.

A second embodiment of the present invention in which the closing switch is opened after a predetermined time has passed will be described below with reference to the drawings. FIG. 3 is a circuit diagram showing a second embodiment of the present invention,
2A and 6A correspond to the capacitor 2A and the closing switch 6, respectively, and 1, 3 to 5 and 11 are the same as those described above. In FIG. 3, the voltage source circuit 7 (see FIG. 1) is unnecessary, and only the transient vibration circuit 11 is connected in parallel to the test switchgear 1.

The capacitor 2A is a large-capacity capacitor including the function of the voltage source circuit 7, and supplies a higher voltage and a larger current than the capacitor 2 described above. Closing switch 6A
Is a circuit breaker that turns on and off a high voltage and a large current, and sets a current break point for controlling the passage time of the alternating current i1 supplied to the DUT 1 in cooperation with a timer circuit (not shown). Constitutes a means.

Hereinafter, referring to the waveform diagram of FIG. 4, FIG.
The operation of the second embodiment of the present invention shown in FIG.
In this case, the capacitor 2A is pre-charged with a high voltage charge corresponding to the supply voltage of the voltage source circuit 7. First, similar to the above, when the closing switch 6A is turned on, the reactor 5 is connected in parallel to the test opening / closing device 1, and the AC current i1 on which the direct current component (about -6000A) is superimposed as shown in FIG. It flows to the device 1.

At this time, the AC current i5 flowing through the reactor 5 via the closing switch 6A has a DC component having a polarity exactly opposite to that of the DC component of the AC current i1 supplied to the DUT 1. The alternating current i5 is the alternating current i
Since the AC component has a larger amplitude than the DC component of 5, the zero point appears at the same rate as the AC current of the commercial frequency.

Therefore, when a breaker is used as the closing switch 6A and the closing switch 6A is cut off by the above-mentioned timer circuit after a predetermined time (several 10 ms to 100 ms) has passed after the closing switch 6A is closed, the AC current i5
The AC current i1 can be cut off at the zero point of.

The direct current component of the alternating current i1 supplied to the test switchgear 1 side disappears when the alternating current i5 flowing to the closing switch 6A side is cut off.
After the interruption, the zero point of the alternating current i1 can be reached quickly as shown in FIG. In this way, the passage time of the alternating current i1 supplied to the DUT 1 can be determined.

Example 3. In the first and second embodiments, as shown in FIGS. 2 and 4, the direct current component superimposed current (zero miss current) is made substantially constant, and the timer circuit gives the zero point of the alternating current i1 after a predetermined time. However, instead of using the timer circuit, the AC current i1 may be attenuated over time and the zero point may be automatically given. A third embodiment of the present invention that attenuates the zero miss current will be described below with reference to the drawings.

FIG. 5 is a circuit diagram showing a third embodiment of the present invention, in which 1 to 6A and 11 are the same as those described above.
12 is a resistor connected in series to the test switchgear 1,
The direct current component superimposed on the alternating current i1 is attenuated.

Next, the operation of the third embodiment of the present invention will be described with reference to the waveform chart of FIG. Also in this case,
It is assumed that the capacitor 2A is charged with high voltage charges. When the closing switch 6A is turned on in the same manner as described above, the alternating current i1 flows through the DUT 1, but since the resistor 12 is inserted, the alternating current i1 is attenuated as shown in FIG. The zero point is reached after a predetermined time.

That is, the resistor 12 connected in series to the DUT 1 controls the passage time of the AC current i1 supplied to the DUT 1 by controlling the amount of attenuation of the AC current i1. At this time, the decay time constant τ of the direct current component is expressed by the following equation using the inductance value L of the reactors 4 and 5 and the resistance value R of the resistor 12.

Τ = L / R

From the above equation, if the inductance value L of the reactors 4 and 5 is constant, the resistance value R of the resistor 12 is
By appropriately setting, the passage time of the alternating current i1 supplied to the DUT 1 can be set to a predetermined time (several 10 ms to 100 ms) required for the interruption test.

Embodiment 4 FIG. In the second embodiment, the closing switch 6 is operated after a predetermined time has elapsed since the closing switch 6A was closed.
Although the zero point is given to the AC current i1 by opening A, the impedance of the reactor 4 may be lowered after a lapse of a predetermined time from turning on the closing switch 6A to give the zero point to the AC current i1.

A fourth embodiment of the present invention in which the impedance of the reactor 4 is lowered to give a zero point will be described below with reference to the drawings. 7 is a circuit diagram showing a fourth embodiment of the present invention, in which 1 to 6A and 11 are the same as those described above.

Reference numeral 13 is a third opening / closing switch (hereinafter referred to as closing switch) which is connected in parallel to the reactor 4 and closed by a timer circuit, and 14 is a third reactor (hereinafter simply referred to as closing switch) connected in series to the closing switch 13. Reactor). The series circuit composed of the closing switch 13 and the reactor 14 cooperates with the timer circuit to supply the test opening / closing device 1 by inserting the reactor 14 in parallel with the reactor 4 after a predetermined time has elapsed since the closing switch 6A was closed. The passing time of the alternating current i1 is controlled.

Next, the operation of the fourth embodiment of the present invention will be described with reference to the waveform chart of FIG. In this case, when the closing switch 13 is closed by the timer circuit after a lapse of a predetermined time after the closing switch 6A is closed, the reactors 4 and 14 form a parallel circuit, and the reactor 5 and the reactor opening / closing device 1 inserted into the reactor. The impedance of the circuit drops.

As a result, as shown in FIG. 8, the closing switch 6
After about 100 ms has elapsed from the input of A, the amplitude of the AC component of the AC current i1 increases, and the AC current i1 supplied to the DUT 1 reaches a zero point. Although the above embodiments have been individually described, it goes without saying that even if the embodiments are combined and applied in a duplicated manner, the same effect can be obtained.

[0056]

As described above, according to the first aspect of the present invention, a capacitor for supplying an alternating current to the DUT, and the first capacitor inserted between the capacitor and the DUT. A reactor; a first opening / closing switch inserted between the capacitor and the test opening / closing device; a second opening / closing switch connected in parallel to a series circuit including the test opening / closing device and the first reactor; Second reactor for connecting a DC component larger than the amplitude of the alternating current to the test switchgear in series with the switchgear and the switchgear of the testgear after a predetermined time has passed from the turning on of the second switch. Since a current interruption point setting means for giving a zero point to the current is provided, and large equipment for superimposing the zero miss current is unnecessary,
There is an effect that a zero-miss current interruption test circuit capable of supplying an alternating current, which does not reach the zero point for a predetermined time, to the test switchgear by using a relatively small-sized equipment and a simple control sequence.

According to a second aspect of the present invention, in the first aspect, the current breaking point setting means includes a discharge gap connected in parallel to the switchgear under test and a transient vibration circuit connected in series to the discharge gap. It includes a voltage source circuit that includes the voltage source circuit and a timer circuit that conducts the discharge gap after a lapse of a predetermined time from the turning on of the second open / close switch, and does not require a large facility for superimposing a zero-miss current. There is an effect that a zero-miss current interruption test circuit capable of supplying an alternating current, which does not reach the zero point for a predetermined time, to the DUT by using the equipment and a simple control sequence.

According to a third aspect of the present invention, in the first or second aspect, the current interruption point setting means is:
Since the parallel circuit including the second reactor is turned on / off by including the timer circuit that opens the second on / off switch after a predetermined time has passed from the turning on of the second on / off switch, relatively small equipment and easy control. By using the sequence, it is possible to obtain a zero-miss current interruption test circuit that can supply an alternating current that does not reach the zero point for a predetermined time to the test switch device.

According to a fourth aspect of the present invention, in any one of the first to third aspects, the current cut-off point setting means includes a resistor connected in series to the switchgear under test, and an alternating current Since the direct current component that is superimposed on the current is automatically attenuated, large equipment for superimposing the zero-miss current becomes unnecessary, and relatively small equipment and an easy control sequence are used for a predetermined time. There is an effect that a zero-miss current interruption test circuit capable of supplying an alternating current that does not reach the zero point to the test switching device can be obtained.

According to a fifth aspect of the present invention, in any one of the first to fourth aspects, the current interruption point setting means includes a third reactor connected in parallel with the first reactor, Third connected in series to the third reactor
The opening / closing switch and the timer circuit for opening the third opening / closing switch after a lapse of a predetermined time from the turning on of the second opening / closing switch are made to change the reactor value. It is possible to obtain a zero-miss current interruption test circuit that can supply an AC current that does not reach the zero point for a predetermined time to the switchgear under test using relatively small equipment and a simple control sequence. It is effective.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a first embodiment of the present invention.

FIG. 2 is a waveform diagram for explaining the operation of the first embodiment of the present invention.

FIG. 3 is a circuit diagram showing a second embodiment of the present invention.

FIG. 4 is a waveform diagram for explaining the operation of the second embodiment of the present invention.

FIG. 5 is a circuit diagram showing a third embodiment of the present invention.

FIG. 6 is a waveform diagram for explaining the operation of the third embodiment of the present invention.

FIG. 7 is a circuit diagram showing a fourth embodiment of the present invention.

FIG. 8 is a waveform diagram for explaining the operation of the fourth embodiment of the present invention.

FIG. 9 is a circuit diagram showing a conventional zero-miss current interruption test circuit.

FIG. 10 is a waveform diagram for explaining the operation of a conventional zero-miss current interruption test circuit.

[Explanation of reference numerals] 1 test opening / closing device, 2 2A capacitor, 3 first opening / closing switch, 4 1st reactor, 5 2nd reactor, 6 and 6A 2nd opening / closing switch, 7 voltage source circuit, 9 Discharge gap, 11 Transient vibration circuit, 12 Resistor, 13 Third open / close switch, 14 Third reactor, i1 AC current.

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Suenobu Hamano 8-1-1 Tsukaguchihonmachi, Amagasaki City Mitsubishi Electric Corporation Itami Works

Claims (5)

[Claims] 1. A capacitor for supplying an alternating current to a device under test, a first reactor inserted between the capacitor and the device under test, the capacitor and the device under test A first opening / closing switch inserted between the second opening / closing switch, a second opening / closing switch connected in parallel to a series circuit including the test opening / closing device and the first reactor, and a second opening / closing switch connected in series. And a second reactor for supplying a direct current component larger than the amplitude of the alternating current to the test opening / closing device, and a zero point in the current of the test opening / closing device after a lapse of a predetermined time from turning on of the second opening / closing switch. A zero-miss current interruption test circuit including a current interruption point setting means for giving a current. 2. The current interruption point setting means includes a voltage source circuit including a discharge gap connected in parallel to the test opening / closing device and a transient vibration circuit connected in series to the discharge gap, and the second opening / closing switch. 2. The zero-miss current interruption test circuit according to claim 1, further comprising a timer circuit which conducts the discharge gap after a lapse of a predetermined time from turning on. 3. The current cut-off point setting means includes a timer circuit for opening the second open / close switch after a predetermined time has elapsed since the second open / close switch was turned on. 2 zero-miss current interruption test circuit. 4. The zero-miss current interruption test circuit according to claim 1, wherein the current interruption point setting means includes a resistor connected in series with the DUT. . 5. The current interruption point setting means includes a third reactor connected in parallel to the first reactor, a third opening / closing switch connected in series to the third reactor, and the second reactor. The zero-miss current interruption test circuit according to any one of claims 1 to 4, further comprising: a timer circuit that opens the third open / close switch after a predetermined time has elapsed since the open / close switch was turned on.