JPH09200943A - Circuit breaker with open phase protection for neutral conductor in single-phase three-wire distribution line - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to provide a selective setting of alarm generation or immediate circuit break during the open phase of a neutral conductor depending on the state of the load by providing switching means at the output side of an overvoltage monitor circuit monitoring the overvoltage during the open phase of the neutral conductor and by connecting an alarm output circuit and an overvoltage trip circuit through the switching means. SOLUTION: Inside the main body 1 of a circuit breaker, a protection circuit 15 for the open-phase neutral conductor of single-phase three-wire lines connected to an overvoltage detection lead wire 2 is provided; and also an overvoltage monitor circuit 40, an alarm output circuit 41, an overvoltage trip circuit 42, and a switch device 43 are provided. Here, by the setting of a change-over switch 43c, an alarm output circuit 41 is operated through a first signal circuit 43a based on an overvoltage occurrence signal output from the overvoltage monitor circuit 40, or the operation of the overvoltage trip circuit 42 is selected through a second signal circuit 43b. By doing this, if an open phase occurs at the neutral conductor, either alarm generation or the break of distribution line circuit is selected thereby performing adequate open- phase protection corresponding to the state of the load.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a circuit breaker with an AA neutral line open phase protection for detecting an open phase of a neutral line in a single-phase three-wire distribution line and protecting a load device. .

[0002]

2. Description of the Related Art FIGS. 7 and 8 show, for example, JP-A-1-30.
It is explanatory drawing of the conventional breaker with an AA neutral line open phase protection shown by the 7133 publication. In the figure, reference numeral 1 is a circuit breaker main body, which has a built-in open-phase detection unit (not shown) for detecting open-phase of a neutral wire of a single-phase three-wire distribution line, as well known as an overcurrent cut-off mechanism. ing. Reference numeral 2 denotes an overvoltage detection lead wire connected to the open-phase detection section, the outer end 2a of which is connected to a neutral wire of a single-phase three-wire type distribution line circuit as described later, and a neutral point on the power supply side from the connection point. It is for monitoring open phase due to wire disconnection or poor connection.

FIG. 8 shows a circuit breaker with a neutral line open phase protection built in a distribution board and shows a connection state inside the distribution board. That is, 3 is a distribution board, R, N, and T are lead-in wires of a single-phase three-wire type distribution line circuit drawn into the distribution board from an external main circuit. R and T are single-phase R-phase and T-phase, respectively. Phase, N is the N phase of the neutral line. 1 is a main body of a circuit breaker with an AA neutral line open phase protection connected to the lead-in wires R, N and T, 2 is an overvoltage detection lead wire, 2a is a terminal connected to the outer end of the lead wire 2, r, n, and t are distribution bus bars of a single-phase three-wire distribution line circuit arranged in the distribution board. 4, 5 and 6 are branch circuit breakers connected between the R-phase power distribution bus r and the N-phase power distribution bus (neutral wire) n among the above-mentioned power distribution bus lines r, n and t, Each load side wiring 7 is wired as shown by an arrow A and is connected to an appropriate load device (not shown). In addition, 8, 9, and 10 are T out of r, n, and t of the distribution bus.
A branch circuit breaker connected between a phase distribution bus t and an N-phase distribution bus (neutral line) n, in which each load side wiring 11 is wired as shown by an arrow B, and an appropriate load is provided. It is connected to a device (not shown). The terminal 2a at the outer end of the overvoltage detection lead wire 2 is the outermost end n ₀ of the N-phase power distribution bus n.
It is connected to the with screws.

In the above structure, when the N-phase power distribution bus (neutral wire) n is disconnected due to a disconnection, one load distribution bus, for example R, is connected to the load device connected to the open phase portion.
When the voltage of the load connected to the phase distribution bus r becomes higher than the rated non-operation overvoltage, the voltage of the load connected to the other distribution bus, for example, the T-phase distribution bus t, decreases correspondingly. Therefore, the load device to which the overvoltage is applied may be burned. Therefore, the overvoltage is detected, and the circuit breaker 1 with AA neutral line open-phase protection is opened before the burnout. In this case, the terminal 2a of the overvoltage detection lead wire 2 is N so that the range to which all the load devices are connected is protected.
It is so arranged that it is connected to the outermost end n ₀ of the phase distribution bus n.

[0005]

In the conventional breaker with AA neutral line open-phase protection as described above, the open phase occurs due to a disconnection or the like in the N-phase power distribution bus (neutral line) n, and an overvoltage occurs. When the rated overvoltage exceeds 120V, the open phase detector of the circuit breaker 1 judges that there is a phase break and trips the circuit breaker 1 to shut it off. There is no warning in advance of this interruption, and the power supply to the important load circuit is stopped due to a sudden power failure, so there is a problem that the influence on the load equipment becomes extremely large.

The present invention has been made in order to solve the above problems. A first object of the present invention is to set whether an alarm is issued or a trip is cut off immediately when the phase of the neutral wire is lost. (EN) A circuit breaker with AA neutral line open-phase protection that can be selectively set according to the state of load equipment. Also,
The second purpose is to automatically operate so as to generate an alarm when the overvoltage at the open phase of the neutral line is lower than a predetermined value, and to trip and cut off immediately when the overvoltage is higher than the predetermined value. Thus, the circuit breaker with AA neutral line open-phase protection is obtained.

[0007]

In a circuit breaker with AA neutral line open-phase protection according to the present invention, an overvoltage for monitoring an overvoltage generated when a neutral line of a single-phase three-wire distribution line is out of phase. A monitoring circuit; switching means for switching the overvoltage signal output from the overvoltage monitoring circuit to output to either the first signal circuit or the second signal circuit; and a switching circuit connected to the first signal circuit, An alarm output circuit that operates when the first signal circuit outputs an overvoltage signal; and an overvoltage trip circuit that is connected to the second signal circuit and that operates when the second signal circuit outputs an overvoltage signal. According to the state of the load equipment, an alarm is issued when the neutral wire phase is lost, or the trip is cut off immediately, or it can be selectively set by the switching means.

Further, when the overvoltage generated by the neutral phase open phase of the single-phase three-wire distribution line reaches a predetermined first overvoltage,
An overvoltage monitoring circuit that outputs a first overvoltage signal and outputs a second overvoltage signal when a predetermined second overvoltage is reached; an alarm output circuit that operates by the first overvoltage signal; It is equipped with an overvoltage trip circuit that operates according to the overvoltage signal in 2 above, so that an alarm is generated even if the value of the overvoltage at the time of a neutral wire open phase, or whether the circuit breaker trips automatically It was done.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1. FIG. 1 shows an electric circuit diagram of a circuit breaker with AA neutral line open-phase protection which is an embodiment of the present invention. In the figure, 1 is a circuit breaker body, 20R, 20N, 2
OT is a power supply side terminal, and a neutral wire is connected to 20N. 2
1R, 21N and 21T are load side terminals, 2 is a circuit breaker body 1
It is a lead wire for overvoltage detection derived from
On the load side of the circuit breaker body 1, a is connected to the neutral wire of the single-phase three-wire distribution line circuit. Reference numeral 15 denotes an electronic circuit for protecting the AA neutral line open phase, which is provided inside the circuit breaker main body 1 and is connected to the overvoltage detection lead wire 2.
0, an alarm output circuit 41, an overvoltage trip circuit 42, a switching device 43 and the like. The circuit breaker portion of the circuit breaker main body 1 is mainly a well-known wiring circuit breaker or earth leakage circuit breaker installed in a general household where power is supplied by a single-phase three-wire distribution line or a small-scale store. The description of the configuration is omitted.

The overvoltage monitoring circuit 40 has a comparator 40a and an overvoltage signal output circuit 40c, for example, as shown in FIG. 2, and compares the voltage signal from the overvoltage detection lead wire 2 and the rated inoperative overvoltage with the comparator 40a. , The voltage signal is a predetermined overvoltage value, and the rated inoperative overvoltage (for example, 120V)
When the above is reached, a signal is output to the overvoltage signal output circuit 40c, and the overvoltage signal output circuit 40c outputs an overvoltage generation signal.

The switching device 43 sends the overvoltage generation signal from the overvoltage monitoring circuit 40 to the first signal circuit 43a or the second signal circuit 43a.
The signal circuit 43b is switched to output. That is, a changeover switch 43c that is manually changed over is provided on the outer surface of the circuit breaker body 1, and either the first signal circuit 43a or the second signal circuit 43b is selected and changed over as necessary. .

The alarm output circuit 41 has a thyristor 41a and a relay 41b whose switching contact is switched when excited, as shown in FIG.
The gate of a is connected to the first signal circuit 43a.
The switching contact of the relay 41b is connected to the alarm output terminals 41c, 41d, 41e installed on the outer surface of the circuit breaker body 1. The alarm device connected to the alarm output terminals 41c, 41d, 41e is an alarm device connected between the alarm output terminals 41c, 41d, which operates when the circuit of the alarm output terminals 41c, 41d is closed. And between the alarm output terminals 41c and 41e, the alarm output terminal 41c,
An alarm device which operates when the circuit of 41e opens is connected.

The overvoltage trip circuit 42 includes a thyristor 42a and an electromagnetic trip mechanism 42b, as shown in FIG. 4, for example.
And the gate of the thyristor 42a is connected to the second signal circuit 43b. The electromagnetic tripping mechanism 42b opens the contactor 1a of the circuit breaker 1 when activated.

In the circuit breaker with AA neutral line open-phase protection constructed as described above, the changeover switch 43c of the changeover device 43 is preliminarily set in accordance with the state of the load device (not shown).
To the first signal circuit 43a or the second signal circuit 43b.
Select either one of them and switch it. For example, by switching to the first signal circuit 43a, when the overvoltage generation signal is output from the overvoltage monitoring circuit 40, the alarm output circuit 41
Is activated and an alarm device (not shown) connected to the alarm output terminals 41c, 41d, 41e can inform that the neutral wire has lost phase. When the changeover switch 43c of the changeover device 43 is switched to the second signal circuit 43b, when the overvoltage generation signal is output from the overvoltage monitoring circuit 40,
The contact 1a of the circuit breaker 1 operates when the overvoltage trip circuit 42 operates.
Open the circuit to protect the load equipment.

Embodiment 2 In the first embodiment,
Although it is configured such that either an alarm is issued when the neutral line is out of phase or the tripping is cut off immediately by the switching means, as shown in FIG. 5, the overvoltage when the neutral line is out of phase is set. However, if it is lower than a predetermined value, an alarm is generated, and if it is higher than the predetermined value, it should be tripped and shut off immediately.
It can also be configured to operate automatically. That is,
FIG. 5 is an electric circuit diagram of a circuit breaker with AA neutral line open-phase protection that is Embodiment 2 of the present invention. In the figure, 1 is a circuit breaker body, 20R, 20N and 20T are power source side terminals, 21R, 21N and 21T are load side terminals, 2 is an overvoltage detection lead wire derived from the circuit breaker body 1, and its terminal 2a is On the load side of the circuit breaker body 1, it is connected to the neutral wire of the single-phase three-wire distribution line circuit. Reference numeral 25 is an electronic circuit for protecting the AA neutral wire open phase provided inside the circuit breaker main body 1 and connected to the overvoltage detection lead wire 2. The overvoltage monitoring circuit 50, the alarm output circuit 41, and the overvoltage trip circuit 42. Etc.

The overvoltage monitoring circuit 50 includes a first comparator 50a, a second comparator 50b, and a second comparator 50b, as shown in the figure.
It has an overvoltage signal output circuit 50c. The first comparator 50a and the second comparator 50b are connected in parallel to the overvoltage detection lead wire 2, and the first comparator 50a is
The voltage signal from the overvoltage detection lead wire 2 is constantly compared with the rated non-operation overvoltage, and the voltage signal shows a predetermined overvoltage value (for example, 11
5V) or more, an overvoltage generation signal is output to the first signal circuit 50d via the overvoltage signal output circuit 50c.
The second comparator 50b constantly compares the voltage signal from the overvoltage detection lead wire 2 with the rated inoperative overvoltage, and when the voltage signal exceeds a predetermined overvoltage value (for example, 120V), the second comparator 50b outputs the second voltage via the overvoltage signal output circuit 50c. The overvoltage generation signal is output to the signal circuit 50e.

The alarm output circuit 41 is similar to the alarm output circuit 41 in the first embodiment, and has a thyristor and a relay whose switching contact is switched when excited, and the gate of the thyristor has a first signal circuit. It is connected to 50d. The switching contact of the relay is also connected to the alarm output terminals 41c, 41d and 41e provided on the outer surface of the circuit breaker main body 1 in the same manner as in the first embodiment. The overvoltage trip circuit 42 is also similar to the overvoltage trip circuit 42 in the first embodiment, and has a thyristor and an electromagnetic trip mechanism, and the gate of the thyristor has the second signal circuit 50.
connected to e. The electromagnetic tripping mechanism is adapted to open the contact 1a of the circuit breaker 1 when activated.

In the circuit breaker with AA neutral line open-phase protection constructed as described above, when the voltage signal from the overvoltage detection lead wire 2 reaches 115V to 120V, the overvoltage is generated in the first signal circuit 50d. The signal is output. The alarm output circuit 41 is activated by this overvoltage generation signal, and an alarm device (not shown) connected to the alarm output terminals 41c, 41d, and 41e can notify that the neutral line is out of phase. When the voltage signal from the overvoltage detection lead wire 2 becomes 120 V or more, the overvoltage generation signal is output to the second signal circuit 50e. The overvoltage trip circuit 42 is activated by this overvoltage generation signal to open the contact 1a of the circuit breaker 1 to protect the load device. In this case, the overvoltage generation signal is also output to the first signal circuit 50d, but since the circuit breaker 1 is opened, no alarm is issued. However, when a self-holding type alarm device is used, it is possible to issue an alarm when the circuit breaker 1 is open.

Embodiment 3 Embodiments 1 and 2 above
All of them may open the circuit breaker 1 when the phase of the neutral line is missing, but some load devices want to avoid sudden opening. In this case, if only the alarm output circuit 41 is provided as shown in FIG. 6, the electronic circuit 35 for AA neutral line open phase protection becomes simple, and the AA neutral line open phase protection is inexpensive. A circuit breaker with a switch can be provided.

[0020]

Since the present invention is constructed as described above, it has the following effects.

When the neutral line is out of phase due to a disconnection of the single-phase three-wire type distribution line or a connection failure, etc., an alarm for the disconnection of the neutral line or a means for interrupting the distribution line circuit is provided as a circuit breaker. Since it is built into one of the circuit breakers such as a circuit breaker or an earth leakage circuit breaker, and it is possible to select whether to generate an alarm or to interrupt the distribution line circuit, no special equipment is required and it is suitable for the condition of the load equipment. Open-phase protection is provided.

Further, when the overvoltage at the time of the neutral wire open phase is lower than a predetermined value, an alarm is generated, and when the overvoltage is higher than the predetermined value, an automatic selection operation is performed so as to trip and cut off immediately. With such a configuration, when the danger level to the load device is low, it is possible to prevent an unexpected power failure only by issuing an alarm.

[Brief description of drawings]

FIG. 1 is an electric circuit diagram showing a circuit breaker with AA neutral line open-phase protection that is an embodiment of the present invention.

FIG. 2 is an electric circuit diagram of an overvoltage monitoring circuit.

FIG. 3 is an electric circuit diagram of an alarm output circuit.

FIG. 4 is an electric circuit diagram of an overvoltage trip circuit.

FIG. 5 is an electric circuit diagram showing a circuit breaker with AA neutral line open-phase protection that is Embodiment 2 of the present invention.

FIG. 6 is an electric circuit diagram showing a circuit breaker with AA neutral line open-phase protection that is Embodiment 3 of the present invention.

FIG. 7 is a perspective view showing a conventional breaker with AA neutral line open-phase protection.

FIG. 8 is an explanatory diagram showing a connection example of a circuit breaker with a conventional AA neutral line open-phase protection to a single-phase three-wire circuit.

[Explanation of symbols]

1 breaker body, 1a contactor, 2 overvoltage detection lead wire, 15, 25, 35 AA neutral wire open phase protection circuit, 40
Overvoltage monitoring circuit, 41 alarm output circuit, 42 overvoltage trip circuit, 43 changeover device, 43c changeover switch,
50 Overvoltage signal output circuit.

Claims (2)

[Claims] 1. An overvoltage monitoring circuit for monitoring an overvoltage generated due to an open phase of a neutral line of a single-phase three-wire distribution line, and an overvoltage signal output from this overvoltage monitoring circuit for a first signal circuit or a second signal. Switching means for switching to output to any one of the circuits, and an alarm which is connected to the first signal circuit and is activated when the overvoltage signal is output in a state where the switching means is switched to the first signal circuit. An output circuit and an overvoltage trip circuit which is connected to the second signal circuit and which operates when the switching means is switched to the second signal circuit and is activated when the overvoltage signal is output. AA neutral circuit breaker with open-phase protection. 2. When the overvoltage generated by the neutral phase open phase of the single-phase three-wire distribution line reaches a predetermined first overvoltage, the first
An overvoltage monitoring circuit that outputs a second overvoltage signal when a predetermined second overvoltage is reached, an alarm output circuit that operates according to the first overvoltage signal, and the second overvoltage signal that outputs the second overvoltage signal. A circuit breaker with AA neutral line open-phase protection, comprising: an overvoltage trip circuit that is activated by an overvoltage signal.