JPH10336881A - Three-phase four-wire neutral line phase interruption detection device and circuit breaker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain complete opening and closing operations and use a low- pressure and small-sized test switch by forming an impedance element which is connected to the gate terminal of a semiconductor switching element and the input side of a comparator and restricts voltage applied to the test switch. SOLUTION: For the operation test of a three-phase four-wire neutral line phase interruption detection device, a test switch TS is turned on. A current limit resistor 26 is bypassed by the test switch TS. With a portion between collector and emitter of a transistor 41 and the test switch TS, a voltage divider resistor 23 is shorted, so that most current runs via the test switch TS and the inptu voltage of the comparator 2 rises beyond VREF. The comparator 2 outputs a trip signal to a trigger circuit 3, and a relay circuit 4 receives the trigger signal of the trigger circuit 3 to operate a contact 5. The test switch TS is controlled so as to keep its voltage below fixed voltage by a Zener diode 31, thus it is possible to turn it off easily after the operation confirmation of the contact 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a three-phase four-wire circuit which detects an abnormal voltage applied to a main circuit due to a phase loss of a neutral wire of a three-phase four-wire circuit and outputs the contact. The present invention relates to a neutral-wire open-phase detection device and a circuit breaker that cuts off current supply to a main circuit according to the output of the contact.

[0002]

2. Description of the Related Art FIG. 6 is a circuit diagram showing a conventional single-phase three-wire circuit breaker disclosed in, for example, Japanese Utility Model Laid-Open No. 4-725332. In FIG. 6, 102 is a neutral line, 103 is a voltage line, 104 is a voltage line, 107 is connected to a detection circuit 110, and the other of the voltage dividing resistors 108 and 109, the neutral line 102 and the voltage line 104 are connected. A voltage dividing circuit for dividing a voltage between the two, a thyristor having a gate connected to the detection circuit 110, an anode connected to the electromagnet 112 via a diode, and a cathode connected to the voltage line 104 via the diode; An electromagnet 113 is connected to the thyristor 111 via the voltage line 103 and the diode, and 113 is a test circuit composed of a test switch 114 with a resistor and a resistor 115 connected in series, and connected in parallel to the voltage dividing resistor 108.

Next, the operation of the conventional single-phase three-wire circuit breaker will be described. When the neutral line 102 is non-open and the test switch with resistance 114 is OFF, the voltage of the voltage dividing resistor 109 of the voltage dividing circuit 107 does not exceed a predetermined value, so that the detection circuit 110 does not output to the thyristor 111, Single-phase three-wire circuit breakers do not operate.

When the test switch with resistor 114 is ON, both ends of the voltage dividing resistor 108 are bypassed by the test circuit 113 including the resistor 115 and the switch with resistor 114, the voltage of the voltage dividing resistor 108 decreases, and the voltage of the voltage dividing resistor 109 decreases. Voltage rises. At this time, since the voltage of the voltage dividing resistor 109 exceeds a predetermined value, the detection circuit 110
Output to the gate. When the output of the detection circuit 110 is received by the thyristor 111, the anode-cathode of the thyristor 111 conducts, and the contact of the circuit breaker is tripped by the electromagnet 112.

[0005]

In the above-described conventional single-phase three-wire circuit breaker, since the alternating current is converted into the direct current by half-wave rectification, the voltage applied to the test circuit 13 has a zero point. On the other hand, in a circuit such as the conventional three-phase four-wire circuit breaker shown in FIG. 7, since the alternating current is converted into direct current by full-wave rectification, the voltage applied to the test circuit is a direct current voltage as shown in FIG. Becomes Since this DC voltage has no zero,
As the operating voltage increases, it becomes difficult to open and close the test switch, and there is a problem that a large switch is required.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has been made in consideration of the problems described above.
A three-phase four-wire neutral-phase missing-phase detector and a circuit breaker that can be reliably opened and closed and that can use a low-voltage, small-sized test switch in a phase four-wire neutral-phase missing-phase detector and a circuit breaker. .

[0007]

SUMMARY OF THE INVENTION A three-phase four-wire neutral-phase open-phase detecting apparatus according to the present invention detects an abnormal voltage due to an open phase of a neutral line with a comparator and operates a three-phase four-wire neutral circuit. In a line neutral line open phase detection device, a semiconductor switching element connected in parallel with a voltage dividing resistor via a current limiting resistor, a test switch connected in parallel with the current limiting resistor and bypassing the current limiting resistor when energized. And an impedance element connected to a gate terminal of the semiconductor switching element and an input side of the comparator, for limiting a voltage applied to the test switch.

[0008] The impedance element is a Zener diode. In addition, the relay circuit has one end connected to the DC side of the rectifier circuit and the other end connected to the output side of the trigger circuit, and grounds the gate terminal of the semiconductor switching element in accordance with the operation of the relay coil. And a contact point. The trigger circuit includes a thyristor connected via a relay circuit, and a transistor connected in series to the thyristor and having a base terminal connected to the comparator.

Further, a circuit breaker according to the present invention is a circuit breaker for detecting an abnormal voltage due to an open phase of a neutral line with a comparator, operating a relay circuit to cut off the current supply to a main circuit. A semiconductor switching element connected in parallel with the voltage-dividing resistor via a resistor, a test switch connected in parallel with the current-limiting resistor, and bypassing the current-limiting resistor when energized; a gate terminal of the semiconductor switching element; And an impedance element connected to the input side of the tester and for limiting a voltage applied to the test switch.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1 FIG. Hereinafter, Embodiment 1 of the present invention will be described. FIG. 1 shows a three-phase four-phase fuel cell system according to the first embodiment of the present invention.
FIG. 2 is a diagram illustrating a circuit of a line neutral line open phase detection device. In the figure, reference numeral 1 denotes a three-phase full-wave rectifier circuit composed of diodes 11 to 16, and a value used in a three-phase four-wire circuit (main circuit) is four.
When the voltage is 00 V, the voltage converted to DC by the three-phase full-wave rectifier circuit 1 becomes 200 V or more. 2 is connected via a voltage dividing resistor 21 connected to the DC side of the three-phase full-wave rectifier circuit 1 so that this voltage becomes a power supply voltage, and connected to a neutral line N via a voltage dividing resistor 22; A comparator for comparing the voltage of the neutral line N with a threshold value V _REF , a trigger circuit 3 connected to the output side of the comparator 2, a relay circuit 4 connected to the output side of the trigger circuit 3, and a reference numeral 5, These contacts are opened and closed by the relay circuit 4.

Reference numerals 22 and 23 denote a neutral line N of the main circuit and a comparator 2
, A voltage dividing resistor connected in series with the input terminal of the comparator 2, a sensitivity adjusting resistor connected in parallel to the input terminal of the comparator 2, and a collector 41 connected between the voltage dividing resistor 22 and the voltage dividing resistor 23. A transistor (semiconductor switching element) having a base (gate terminal) connected to a collector via a resistor 25 and an emitter connected to a current limiting resistor 26;
Reference numeral 31 denotes a Zener diode (impedance element) having a cathode connected to the base of the transistor 41, an anode connected to the input side of the comparator 2, and limiting a voltage applied to the test switch TS.
Is a test switch connected to both ends of the test switch. When the neutral line N is out of phase and an abnormal voltage is generated in a load (not shown), the voltage dividing resistors 22 and 23 are operated so that the comparator 2 operates.
Selects a resistor having a resistance value smaller than the resistance values of the resistor 25 and the current limiting resistor 26.

Next, the operation will be described. [Normal Operation] In an ordinary operation, the test switch TS is OFF and the transistor 41 is turned on.
6 is limited to a constant voltage by the Zener diode 31, so that the current flowing to the comparator 2 via the transistor 41 is suppressed to a small level. Therefore, most of the current flows through the voltage dividing resistor 23 and the sensitivity adjusting resistor 24, and the voltage of the sensitivity adjusting resistor 24 does not rise to the threshold value VREF, so that the comparator 2 does not output a signal to the trigger circuit 3. .

When the neutral line N is open, an abnormal voltage (high voltage) flows from the load (not shown) to the neutral line N.
An excessive current flows through the voltage dividing resistor 23, the voltage of the sensitivity adjusting resistor 24 becomes higher than the threshold value V _REF , and the comparator 2 outputs a trip signal to the trigger circuit 3.

[Operation Test] In an operation test of the three-phase / four-wire neutral-phase missing-phase detecting device, a test switch TS is turned on. At this time, the current limiting resistor 26 is bypassed (short-circuited) by the test switch TS, and the voltage dividing resistor 23 is short-circuited between the collector and the emitter of the transistor 41 and the test switch TS. And the input voltage of the comparator 2 becomes V
It rises above REF. Then, the comparator 2 outputs a trip signal to the trigger circuit 3, and the relay circuit 4 receives the trigger signal of the trigger circuit 3 and operates the contact 5.
At this time, since the test switch TS is suppressed to a certain voltage or less by the Zener diode 31, it can be easily turned off after the operation of the contact 5 is confirmed.

The test switch T is constructed as described above.
S is suppressed to a certain voltage or less, for example, several volts or less, by the Zener diode 31. Therefore, even in the case of a zero-point DC current obtained by full-wave rectifying a three-phase four-wire circuit, it can be reliably opened and closed, and a small test A switch TS can be used. For example, in the conventional three-phase four-wire circuit described with reference to FIG. 12, if the voltage used is an AC circuit of 440 V, a DC voltage of 200 V DC or more is applied to the test switch when a sufficient test current is applied to the detection circuit by the test circuit. T
It was applied to S and could not be opened and closed with a small switch.

Although an example in which the zener diode 31 is used as the impedance element for limiting the voltage applied to the test switch TS has been described, a resistor whose terminal is applied to several volts in a steady state may be used. It can be configured at a lower cost. Needless to say, when the zener diode 31 is used, the voltage is maintained at a constant value even in an abnormal situation where a high voltage is applied compared to a steady state.
Since the test switch TS can be turned ON / OFF, the comparator 2 can be protected even in the event of an abnormality.

Embodiment 2 FIG. FIG. 2 is a diagram showing a circuit of a three-phase / four-wire neutral-phase-loss detecting apparatus according to Embodiment 2 of the present invention. In the figure, a relay circuit 4 is a full-wave rectifier circuit 1.
And a switch (contact) SW1 connected to GND and the base of the transistor 41, and the switch SW1 is opened and closed by the relay coil C1. . The other configuration is the same as that of the first embodiment, and the description thereof is omitted.

Next, the operation will be described. At the time of the test operation or the neutral line open phase operation, as described in the first embodiment, the input voltage of the comparator 2 becomes larger than the threshold value V _REF , and the comparator 2 sends the trip signal to the trigger circuit 3. Output, the relay circuit 4 receives the trigger signal of the trigger circuit 3, and the trigger circuit 3 operates the relay coil C1, so that the contact 5 operates (contacts) and the switch SW1
Closes. Then, the base of the transistor 41 is connected to GND by the switch SW1, the current flowing through the test circuit 6 becomes very small, and the input voltage of the comparator 2 becomes equal to or lower than the threshold value V _REF . No output. Thereafter, when the comparator 2 does not output the trip signal to the trigger circuit 3, no current flows to the relay coil C1.

In the three-phase four-wire neutral-phase missing-phase detecting device according to the first embodiment, when the test switch TS is continuously pressed, for example, when the main circuit is 440 VAC, a voltage of approximately 340 VDC is continuously applied to the voltage dividing resistor 22. Applying a high voltage for a long time is not preferable from the viewpoint of protection of the voltage dividing resistor 22. In the second embodiment, the contact point of the switch SW1 connected to the relay coil C1 automatically connects the base of the transistor 41 to GND simultaneously with the test operation.
2, a voltage of about DC340V is not continuously applied,
The voltage dividing resistor 22 can be reliably protected.

Embodiment 3 FIG. 3 is a diagram showing a circuit of a three-phase / four-wire neutral-phase-loss detecting apparatus according to Embodiment 3 of the present invention. In the drawing, reference numeral 32 denotes a Zener diode connected to the input of the comparator 2 and GND. The other configuration is the same as that of the second embodiment, and the description thereof is omitted.

When the neutral line N is out of phase and a voltage greatly exceeding the operating voltage of the three-phase four-wire neutral-phase-loss detecting device is applied to the N-phase, the three-phase four-wire In the sex ray open phase detection device, there is a possibility that an overvoltage is applied to the input of the comparator 2.
On the other hand, in the third embodiment, the Zener diode 32 connected in parallel to the sensitivity adjustment resistor 24 connected to the input side of the comparator 2 prevents the overvoltage from being applied to the input side of the comparator 2, and The sensitivity adjustment resistor 24 can be protected against overvoltage.

Embodiment 4 FIG. 4 is a diagram showing a circuit of a three-phase / four-wire neutral-phase-loss detecting apparatus according to Embodiment 4 of the present invention. In the figure, 27 and 28 are voltage dividing resistors, 42 is a transistor having a base connected to the output side of the comparator 2 and a collector connected to the relay coil C1 via a thyristor 43, and 43 is a resistor 29 between the gate and the cathode. Is connected, the anode is connected to the relay coil C1, the cathode is connected to the collector of the transistor 42, and the gate is
7 is a thyristor connected to the relay coil C <b> 1 via the reference numeral 7. The other configuration is the same as that of the third embodiment, and the description thereof is omitted.

Next, the operation will be described. When the test switch TS is OFF or the neutral line N is not open,
Since the collector and the emitter of the transistor 42 are OFF, a small current flows through the voltage dividing resistors 27 and 28 so that the relay coil cannot operate the contact.

When the test switch is ON or the neutral line N is open, the comparator 2 outputs a trip signal to the transistor 4
2 and the collector and emitter of the transistor 42 conduct, the current flows through the gate of the thyristor 43, and the anode and cathode of the thyristor 43 conduct. When the anode between the thyristor 43 and the emitter of the transistor 42 conducts, a current flows through the relay coil C1, and the contact 5 operates.

With the configuration described above, the thyristor 43 for low voltage can be used as compared with the case where the relay coil is operated by only one thyristor as described in the conventional example. Therefore, the thyristor 43 does not break down due to burnout or the like, and is particularly effective when the main circuit has a high voltage.

Embodiment 5 In the first to fourth embodiments, 3
Although the phase 4 neutral line open phase detecting device has been described, the same effect can be obtained in a circuit breaker in which the external output contact 5 is replaced by a main circuit contact 50 (FIG. 5). FIG. 5 is a diagram showing a circuit breaker circuit having a three-phase / four-wire neutral-phase-loss detecting circuit according to Embodiment 5 of the present invention. In the figure,
Reference numeral 7 denotes a three-phase four-wire neutral-wire open-phase detection circuit constituted by a full-wave rectifier circuit 1, a comparator 2, a trigger circuit 3, a relay circuit 4, and a test circuit 6, 50 denotes a main conductor 8R inside the circuit breaker,
Main circuit contacts provided for 8S, 8T, 8N. Note that other configurations are the same as those of the first to fourth embodiments, and thus description thereof is omitted.

Next, the operation will be described. [Steady state] In a steady state, the test switch TS is OFF, and most of the current flows through the voltage dividing resistor 23 and the sensitivity adjusting resistor 2.
4 and the voltage of the sensitivity adjustment resistor 24 is
_{Since the} signal does not rise to _REF , the comparator 2 does not output a trip signal to the trigger circuit 3 and the main circuit contact 50 does not operate. Further, when the neutral line N is out of phase, an abnormal voltage (high voltage) flows from the load (not shown) to the neutral line N, so that an excessive current flows through the voltage dividing resistor 23 and the voltage of the sensitivity adjusting resistor 24 becomes threshold. The value becomes higher than the value VR _EF , the comparator 2 outputs a trip signal to the trigger circuit 3, and the relay circuit 4 operates (trips) the main circuit contact 50.

[During Operation Test] At the time of an operation test, the test switch TS is turned on. At this time, the current limiting resistor 26 is bypassed (short-circuited) by the test switch TS,
The voltage dividing resistor 23 is short-circuited between the collector and the emitter of the transistor 41 and the test switch TS, and most of the current flows through the test switch TS.
The input voltage of the comparator 2 rises above VREF. Then, the comparator 2 outputs a trip signal to the trigger circuit 3, and the relay circuit 4 receives the trigger signal of the trigger circuit 3 and operates the contact 50.

As described above, the circuit breaker is constructed, and the test switch TS is suppressed to a certain voltage or less, for example, several volts or less by the Zener diode 31, so that the test switch TS can be reliably opened and closed and the three-phase four-wire circuit is completely connected. A small test switch TS can be used even in the case of a wave rectified DC current without a zero point.

In the above-described embodiment, the transistors 41 and 42 have been described as examples. However, the same effect can be obtained in a circuit in which an N-channel field effect transistor (FET) is used.

[0031]

The three-phase / four-wire neutral-phase open-phase detecting device according to the present invention detects an abnormal voltage due to the neutral-phase open phase by a comparator and activates the three-phase / four-wire neutral line. In the open phase detection device, a semiconductor switching element connected in parallel with a voltage dividing resistor via a current limiting resistor, a test switch connected in parallel with the current limiting resistor and bypassing the current limiting resistor when energized, An impedance element that is connected to the gate terminal of the element and the input side of the comparator and limits the voltage applied to the test switch, so that the opening and closing of the test switch is converted into current control of the semiconductor switching element. It can be opened and closed reliably, and a small switch with low pressure can be used for the test switch.

Further, since the impedance element is a Zener diode, the voltage can be kept constant even at the time of abnormality, and the comparator can be protected at the time of abnormality.

The relay circuit has a relay coil having one end connected to the DC side of the rectifier circuit and the other end connected to the output side of the trigger circuit, and a gate terminal of the semiconductor switching element in accordance with the operation of the relay coil. And a contact for grounding the voltage-dividing resistor, so that a high voltage is not continuously applied to the voltage-dividing resistor, and the voltage-dividing resistor can be reliably protected.

The trigger circuit includes a thyristor connected via a relay circuit and a transistor connected in series to the thyristor and having a base terminal connected to the comparator. It can be used, and the thyristor does not break down due to burning or the like.

Further, the circuit breaker according to the present invention is a circuit breaker which detects an abnormal voltage due to an open phase of a neutral line with a comparator, activates a relay circuit, and cuts off current supply to a main circuit. A semiconductor switching element connected in parallel with the voltage-dividing resistor via a resistor, a test switch connected in parallel with the current-limiting resistor, and bypassing the current-limiting resistor when energized; a gate terminal of the semiconductor switching element; And an impedance element that is connected to the input side of the tester and limits the voltage applied to the test switch, so that the open / close of the test switch is converted to the current control of the semiconductor switching element, so that the open / close operation can be performed reliably. A small switch with low pressure can be used for the switch.

[Brief description of the drawings]

FIG. 1 is a diagram showing a circuit of a three-phase / four-wire neutral-phase-loss detecting apparatus according to Embodiment 1 of the present invention.

FIG. 2 is a diagram showing a circuit of a three-phase / four-wire neutral-phase-loss detecting apparatus according to Embodiment 2 of the present invention;

FIG. 3 is a diagram showing a circuit of a three-phase / four-wire neutral-phase-loss detecting apparatus according to Embodiment 3 of the present invention;

FIG. 4 is a diagram showing a circuit of a three-phase / four-wire neutral-phase-loss detecting apparatus according to Embodiment 4 of the present invention.

FIG. 5 is a diagram showing a circuit breaker circuit having a three-phase four-wire neutral-phase-loss detecting circuit according to a fifth embodiment of the present invention.

FIG. 6 is a diagram showing a conventional single-phase three-wire circuit breaker.

FIG. 7 is a diagram showing a conventional three-phase four-wire circuit breaker.

FIG. 8 is a waveform diagram illustrating a voltage applied to a test switch of a conventional three-phase four-wire circuit breaker.

[Explanation of symbols]

1 full-wave rectifier circuit, 2 comparator, 3 trigger circuit, 4 relay circuit, 5 contacts, 6 timer circuit, 7 3-phase 4-wire neutral line open phase detection circuit,
8R, 8S, 8T, 8N main conductor, 11-16
Diode, 21-29 resistance, 41, 42 transistor, 43 thyristor, 50 main circuit contact, TS test switch, SW1 burnout prevention switch, C1 relay coil.

Claims (5)

[Claims] 1. A rectifier circuit connected to each of three phases in a three-phase four-wire circuit, a rectifier circuit connected so that a voltage rectified by the rectifier circuit becomes a power supply voltage, and a three-phase four-wire circuit. A comparator connected to a neutral line in the electric circuit via a voltage dividing resistor, and comparing the voltage of the neutral line with a threshold voltage; a trigger circuit connected to an output side of the comparator;
A relay circuit for activating a contact output in response to an output signal from the trigger circuit, wherein the comparator detects an abnormal voltage due to the open phase of the neutral line by the comparator, and operates the relay circuit. In the neutral-wire open-phase detecting device, a semiconductor switching element connected in parallel with the voltage-dividing resistor via a current-limiting resistor, a test connected in parallel with the current-limiting resistor, and bypassing the current-limiting resistor when energized. A three-phase four-wire neutral, comprising: a switch; and an impedance element connected to a gate terminal of the semiconductor switching element and an input side of the comparator, for limiting a voltage applied to the test switch. Line open phase detector. 2. The three-phase / four-wire neutral-phase missing phase detecting device according to claim 1, wherein the impedance element is a Zener diode. 3. A relay circuit having one end connected to the DC side of the rectifier circuit and the other end connected to the output side of the trigger circuit, and a gate terminal of the semiconductor switching element according to the operation of the relay coil. 3. The three-phase four-wire neutral-phase missing phase detecting device according to claim 1, further comprising a contact for grounding the neutral phase. 4. A trigger circuit comprising: a thyristor connected via a relay circuit; and a transistor connected in series to the thyristor and having a base terminal connected to a comparator. The three-phase four-wire neutral-wire open-phase detection device according to any one of claims 1 to 3. 5. A rectifier circuit connected to each of the three phases in a three-phase four-wire circuit, a rectifier circuit connected so that the voltage rectified by the rectifier circuit becomes a power supply voltage, and a three-phase four-wire circuit. A comparator connected to a neutral line in the electric circuit via a voltage dividing resistor and comparing the voltage of the neutral line with a threshold voltage, a trigger circuit connected to an output side of the comparator,
A relay circuit for activating a main circuit contact output in response to an output signal from the trigger circuit; and a shutoff unit for shutting off energization of the main circuit in accordance with the output of the relay circuit. A circuit switching device that detects an abnormal voltage caused by the comparator, activates the relay circuit, and cuts off current supply to the main circuit; and a semiconductor switching element connected in parallel with the voltage dividing resistor via a current limiting resistor. A test switch connected in parallel with the current limiting resistor and bypassing the current limiting resistor when energized; a voltage connected to the gate terminal of the semiconductor switching element and the input side of the comparator and applied to the test switch A circuit breaker, comprising: