JPH02133031A - Neutral-conductor open-phase detecting point extension unit in single-phase three-wire system - Google Patents

Abstract

PURPOSE:To monitor the open phase of a plurality of branch circuits only by one breaker by inputting the voltage signals of the neutral conductors of a plurality of the branch circuits to a voltage line while only the maximum voltage signal in each voltage signal is input to the breaker with a neutral- conductor open-phase protective device. CONSTITUTION:When open phase is generated in one branch circuit in a single- phase three-wire type distribution line, abnormal voltage is input to the input terminals 2 of a single three-neutral conductor open-phase detecting point extension unit (hereinafter-called a unit-) 4 through open-phase detecting lines 14 from the open-phase detect ing point. A maximum voltage signal is detected by a maximum-value detector in the unit 4. The voltage signal is output to the external terminal 8 of a breaker 6 through a signal output line 13 from the output terminal 3 of the unit 4, and the breaker is operated in response to the voltage signal.

Description

Detailed Description of the Invention A. Field of Industrial Application The present invention is a single-phase three-wire distribution line having a plurality of branch circuits, in which one neutral line is equipped with an open-phase protection device to shut off the circuit in the event of an open phase. This invention relates to an AA neutral wire open phase detection point extension unit that can detect multiple open phase signals so that multiple branch circuits can be monitored and protected with a single unit.

Conventional technology Conventionally, for example, if it is necessary to monitor and protect all open phase detection points of a single-phase three-wire distribution line with multiple branch circuits, a neutral wire open phase protection device for each branch circuit must be shut off. A circuit breaker (hereinafter referred to as a circuit breaker) had to be installed.

C. Problem to be solved by the invention All open phase detection points of a single-phase three-wire distribution line having multiple branch circuits can be connected to an external terminal for detecting abnormal voltage of one circuit breaker equipped with a neutral line open phase protection device. (hereinafter referred to as external terminal), if a neutral wire phase loss occurs in one branch circuit and abnormal voltage occurs, the phase loss detection point of the branch circuit where the phase loss occurred and the other normal branch circuit A potential difference is generated between the open phase detection point and
Even though abnormal voltage is generated due to the intermediate voltage being applied to the external terminal,
The circuit breaker sometimes did not operate. Furthermore, when the load on the branch circuit where the phase loss has occurred is large, an overcurrent may flow through the phase loss detection wire due to the potential difference between the phase loss detection points, and the wire may be burnt out. Therefore, it is not possible to monitor and protect multiple branch circuits from phase failure with just one circuit breaker.
Circuit breakers had to be installed in each branch circuit. Therefore, installing a circuit breaker for each branch circuit would result in extremely high costs and increase the size of the distribution board, making it impractical.

Means for Solving the Problems In order to solve the problems of the conventional art, the present invention inputs the voltage signals of the neutral wires of a plurality of branch circuits to the voltage line, and only receives the maximum voltage signal among the voltage signals. A device will be installed on the conventional single-phase three-wire distribution line that can input the signal to a circuit breaker with a neutral line open-phase protection device. That is, the configuration of the device is that in a single-phase three-wire distribution line in which a circuit breaker with a neutral line open-phase protection device is installed, voltage signals of the neutral line of a plurality of branch circuits for the voltage line are respectively input. an input terminal, a maximum value detection circuit that detects the maximum voltage among the voltage signals and outputs this voltage signal, and uses this voltage signal for abnormal voltage detection of the circuit breaker with neutral line open phase protection device. It consists of an output terminal that outputs to an external terminal.

When an open phase occurs in one branch circuit in a single-phase three-wire power distribution line, abnormal voltage is transmitted from the open phase detection point to the open phase detection point of the AA neutral line of the present invention via the open phase detection line. The maximum voltage signal is input to the input terminal of the expansion unit (hereinafter referred to as the "unit"), and is detected by the maximum value detection circuit inside the unit, and this voltage signal is sent from the output terminal of the unit via the signal output line. This is output to the external terminal of the circuit breaker, and the circuit breaker operates according to this voltage signal. EXAMPLE Hereinafter, an example of the unit of the present invention will be described based on the drawings. As shown in Fig. 1, the unit 4 includes a maximum value detection circuit in which the anode sides of the three rectifiers 1 are respectively input for the open phase signal, and the connection point where the cathode sides are commonly connected is used as the output for the open phase detection signal. It is provided inside a resin case 5 shown in FIG. 2, and each input and output is connected to an input terminal 2 and an output terminal 3 on the surface of the case 5, respectively.

To explain the operation of the circuit breaker 6 used in conjunction with the unit 4, the circuit breaker 6 connects the external terminal 8 to the neutral line N (hereinafter referred to as N) on the load 10 side
Each voltage signal of the neutral wire N to the two voltage lines L1 and L2 (hereinafter referred to as L1 and L2) input from the external terminal 8 is connected to the resistor rl (hereinafter referred to as 'r1). The voltage is alternately rectified every half wave by two rectifiers (hereinafter referred to as D1 and D2) through a series circuit of resistor r2 (hereinafter referred to as r2), and the voltage appearing across r2 is input to the abnormal voltage detection circuit 7. ing. For example, if the neutral line has an open phase at the open phase point 9, resulting in unbalanced load, and a voltage higher than the rated voltage of the distribution line, that is, an abnormal voltage occurs between N and Ll or between N and L2, the external A voltage with a waveform as shown in Fig. 4b is applied between the common connection point of terminal 8 and D1 and D2, that is, to the series circuit of r1 and r2, and the voltage across r2 is also higher than normal, and this is the setting. When the abnormal voltage exceeds this value, the abnormal voltage detection circuit 7 detects the abnormal voltage, and the circuit breaker 6 operates to cut off the power distribution line.

Next, the operation of the maximum value detection circuit for the distribution line when the unit 4 is installed on the AA neutral line distribution line will be explained based on FIG. When the output terminal 3 of the unit 4 is connected to the external terminal 8 of the circuit breaker 6, and each input terminal 2 of the unit 4 is connected to each neutral wire N1 to N3 of the branch circuit, each input terminal 2 of the unit 4 is connected to the external terminal 8 of the circuit breaker 6. Voltage signals of each neutral line with respect to the voltage line are inputted, and the maximum voltage signal among them is outputted from the output terminal 3 of the unit 4 and inputted to the external terminal 8 of the circuit breaker 6. Normally, each input terminal 2 of the unit has
Since the rated voltage of the distribution line is applied and the rated voltage shown in FIG. 4a also appears at the output terminal 3 of the unit 4, the circuit breaker 6 will not malfunction. Now, suppose that the neutral line of one branch circuit, for example N1, has an open phase, and an imbalance occurs in the branch circuit containing this Nl, and an abnormal voltage occurs between N1 and Ll or between N1 and L2. As shown in FIG. 6b, an abnormal voltage is output to the output terminal 3 of the circuit breaker 6 every half wave, and when this abnormal voltage exceeds the set value of the circuit breaker 6, the circuit breaker 6 is activated.
is activated and the power distribution line is cut off.

In addition, if an open phase occurs in the neutral line N of the main circuit 11,
An abnormal voltage is applied to all the input terminals 2 of the unit 4, and a voltage having the waveform shown in FIG.
Protect all branch circuit loads from damage due to overvoltage.

Incidentally, by installing a plurality of units 4 as shown in FIG. 7, the same effect as described above can be obtained even when the number of branch circuits is large. In addition, since the input terminals of unit 4 are electrically insulated from each other due to the reverse blocking property of the rectifier, even if a potential difference occurs between the open phase detection points when abnormal voltage occurs, overcurrent will not flow through the connecting wires. Also, the electric wire will not be burnt out.

G. Effects of the invention Since the present invention has the above configuration, it can be easily installed on a single-phase three-wire distribution line, and multiple branch circuits can be installed in a distribution board etc. where only one circuit breaker is installed. Even in such cases, the entire circuit can be monitored and protected without adding additional circuit breakers. Therefore, the number of circuit breakers installed is significantly reduced compared to the conventional method of installing a circuit breaker for each branch circuit, which significantly reduces the cost of single-phase three-wire distribution lines and significantly reduces wiring work time. In addition, each branch circuit can be monitored and protected without exception.

Furthermore, since the unit of the present invention has a simple circuit configuration and does not require a power source, it can not only be produced at low cost, but also provide functions and effects superior to those of conventional circuit breakers.

As described above, the unit of the present invention has the extraordinary effect of significantly improving the safety and economic efficiency of a single-phase three-wire power distribution line.

[Brief explanation of the drawing]

Fig. 1 is a maximum value detection circuit diagram inside the AA neutral line open phase detection point extension unit according to the present invention, Fig. 2 is an external view of the unit of the present invention, and Fig. 3 is a neutral line open phase protection device. A circuit diagram illustrating the operation of the circuit breaker, FIG. 4a is a diagram showing the voltage waveform during normal operation in FIG. 3, FIG. The figure is a circuit diagram showing this unit installed on a 3-wire distribution line with a circuit breaker installed, Figure 6a is a diagram showing the voltage waveform normally output by the unit in Figure 5, Figure 6 b is a diagram showing a voltage waveform outputted by a unit in one branch circuit in FIG. 5 when an open phase occurs, and FIG. 7 is a circuit diagram showing an embodiment in which a plurality of units are connected to a single three-wire power distribution line. l... Rectifier, 2... Input terminal, 3... Output terminal, 4... Unit body, 5... Resin case, 6...
...Breaker with neutral line open phase protection device, 7...Abnormal voltage detection circuit, 8...External terminal for abnormal voltage detection, 9...Open phase point, lO...Load, 11...・Main circuit, 12...
Branch circuit, 13...Signal output line, 14...Wire for detecting open phase. Patent applicant: Kawamura Electric Industrial Co., Ltd. (Figure 5, Figure 1, Figure 7, LINL2 Voluntary action to write procedural amendments)

Claims (1)

[Claims] In a single-phase three-wire distribution line in which a circuit breaker with a neutral line open-phase protection device is installed, there are input terminals for inputting the voltage signals of the neutral line of the branch circuit branched from the voltage line, and input terminals for inputting the voltage signals of the neutral line of the branch circuit branched from the voltage line, and It consists of a maximum value detection circuit that detects the maximum voltage within and outputs this voltage signal, and an output terminal that outputs this voltage signal to the external terminal for abnormal voltage detection of the circuit breaker with neutral line open phase protection device. An AA neutral wire open phase detection point extension unit characterized by the following.