JPS631815B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is suitable for use in combination with an electronic watt-hour meter having a current limiting function, and for performing a power-off operation in response to a power-off signal sent from the electronic watt-hour meter. The present invention relates to a circuit breaker for electronic wiring.

In general power distribution systems, multiple wiring shields and disconnectors are used for each purpose, such as lighting circuits and outlet circuits, to protect power distribution lines from overloads and short circuits. In order to prevent the load from being used in excess of the contracted rated current value, an ampere current limiter is provided for the metered contract customer. However, the electronic watt-hour meter is equipped with a current limiting function, and when the load exceeds the contracted rated current value, it outputs a shear break signal. If the current limiter can be operated on or off, the current limiter can be omitted.

An object of the present invention is to provide an electronic wiring shear breaker that performs a shear breaker operation in response to one kind of shear breaker signal out of multiple types of shear breaker signals corresponding to multiple rated current values. It is to provide.

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a power distribution system using an electronic watt-hour meter 1 and an electronic wiring sheath disconnector 2 of the present invention. Electronic watt-hour meter 1 is electronic wiring disconnector 2
It sends a sheath disconnection signal to the electronic wiring sheath disconnector 2 through the signal line 3, and thereby the electronic wiring sheath disconnector 2 stops the current flowing through the distribution line 4. cut off

The electronic watt-hour meter 1 has a plurality of current limiting characteristics as shown in FIG. 2 corresponding to multiple rated current values. These current limiting characteristics are the same as those of the current limiter. For example, if a load current of 20 amperes flows, the rated current value is 5 at time t ₁ .
Breakdown signal P ₁ with pulse width T ₁ corresponding to ampere
(Fig. 3), outputs a shrunken signal P ₂ with a pulse width T ₂ corresponding to a rated current value of 10 amperes at a time limit t ₂ , and a pulse width corresponding to a rated current value of 15 amperes at a time interval t ₃ . Outputs T ₃ shear failure signal P ₃ . If the load current exceeds 20 amperes, the output signal _P4 with a pulse width T corresponding to the rated current value of 20 amperes is output, and if the load current exceeds 30 amperes, the output signal P4 with a pulse width _T5 corresponding to the rated current value of 30 amperes is output. Outputs a shear failure signal _P5 . The rating of the electronic wiring sheath breaker 2 is set in advance so that it is disconnected only by a shear break signal having a pulse width corresponding to the rated current value contracted by the consumer with the electric power company.

FIG. 4 is a block diagram of the electronic wiring sheath breaker 2 of the present invention. The overcurrent detection circuit 5 detects the overcurrent flowing through the distribution line 4, the current-voltage conversion circuit 6 rectifies the detected overcurrent and converts it into voltage, and the time limit circuit 7 detects the output voltage of the current-voltage conversion circuit 6. It integrates and outputs an output at the time when the integrated value becomes equal to the reference voltage. This time period is shorter than the time period shown in FIG. The trigger circuit 9 is operated by the output of the time limit circuit 7 inputted via the OR gate 8,
The tripping portion 10 is operated to release.

The input terminal 11 is connected to the signal line 3,
The mustard cutoff signals P ₁ to _{P 5} from the input terminal 11 are input to the cutoff signal identification circuit 12 . The rating setting device 13 is used to select and set in advance one of the multi-step rated current values of 5, 10, 15, 20, 25, 30 amperes, etc. The shear failure signal identification circuit 12 outputs a signal only when a shear failure signal with a pulse width corresponding to the rated current value set by the rating setting device 13 is input, and this signal is sent to the trigger circuit 9 via the OR gate 8. is operated to cause the tripping portion 10 to perform a shear cutting operation.

FIG. 5 shows an example of the beam failure signal identification circuit 12 and the rating setting device 13. In this example, the rating setting device 13
is set to 20 amps. That is, the contact S is connected to the resistor _R4 . This operation will be explained with reference to the time chart of FIG. When the shear failure signals P ₁ to _{P 5} are not input to the input terminal 11, the two inputs of the NAND gate G ₁ are both low level and the output is high level, so
The capacitor _C1 is charged through the resistor _R4 , and the two inputs of the NAND gate _G2 are at high level, and its output is at low level. Therefore, capacitor C ₂ is not charged, and the two inputs of NAND gate G ₃ are at high level and low level,
Its output is low level. A shrunken signal P ₁ ~ having a pulse width T ₁ ~ T ₃ narrower than the pulse width T ₄
When _P5 is input, the output of NAND gate _G1 becomes low level, and the capacitor
The charge on _C1 is discharged by the time constant of resistor _R4 and capacitor _C1 , but the charge on capacitor C1 is discharged before the charge voltage on capacitor _C1 decreases to the input level required for the output of NAND gate _G2 to be inverted. Since the disconnection signals P ₁ to P ₃ disappear, the inputs of NAND gates G ₂ and G ₃ do not change, and the output of NAND gate G ₃ remains at a low level. When the decline signal _P4 is input, the output of NAND gate _G1 becomes low level,
After the charging voltage of the capacitor _C1 decreases and the time period ta elapses, the output of the NAND gate _G2 is inverted to high level.
However, due to the time constant of resistor R ₆ and capacitor C ₂ , the input on the resistor R ₆ side of NAND gate G ₃ is kept at a low level before the time limit tb elapses, so both inputs of NAND gate G ₃ are low. level, and its output becomes high level. After the time limit tb has elapsed, the charging voltage of the capacitor _C2 increases, so the two inputs of the NAND gate _G3 become low level and high level, and the output of the NAND gate _G3 returns to the low level. The high level output of the NAND gate _G3 passes through the OR gate 8 and operates the trigger circuit 9, causing the tripping section 10 to operate.

Although the disconnection signals P ₁ to _{P 5} are pulse width modulated, they may be modulated in other formats, or may be sine waves instead of pulses.

In the present invention, when a shear failure signal is inputted that is modulated in accordance with the rated current value selected and set in advance by the rating setting device, the shear failure signal identification circuit outputs a signal and activates the trigger circuit. Since the tripping section is activated and the tripping part is operated, the tripping section can be activated in response to one type of failure signal among multiple types of failure signals corresponding to multi-stage rated current values. It can be performed. Therefore, by combining it with an electronic watt-hour meter that generates such a no signal or a disconnection signal, the current limiter can be omitted.

[Brief explanation of the drawing]

Fig. 1 is a wiring diagram showing a power distribution system using the wiring sheath disconnector of the present invention, Fig. 2 is a current limit characteristic diagram of an electronic watt-hour meter, and Fig. 3 is an example of a sheath disconnection signal. 4 is a block diagram showing an embodiment of the present invention, FIG. 5 is a circuit diagram showing an example of a shield failure signal identification circuit and a rating setting device, and FIG. 6 is a time chart thereof. 2...Electronic wiring circuit breaker, 5...Overcurrent detection circuit, 6...Current-voltage conversion circuit, 7...Time limit circuit, 9...Trigger circuit, 10...Tripping section,
11... Input terminal, 12... Wear failure signal identification circuit, 13... Rating setting device, P ₁ to P ₅ ... Wear failure signal.

Claims (1)

[Claims] 1. An overcurrent detection circuit that detects overcurrent, a current-voltage conversion circuit that rectifies the detected overcurrent and converts it into voltage, and the output voltage of the current-voltage conversion circuit is integrated, and the integrated value is used as the reference voltage. Select and set a timer circuit that outputs an output at an equal time limit, an input terminal that receives an externally modulated shingle break signal corresponding to a multi-step rated current value, and a multi-step rated current value. a shear failure signal identification circuit that outputs a signal only when a shear failure signal modulated corresponding to the rated current value set by the rating setting device is input; An electronic wiring sheath breaker comprising a trigger circuit operated by the output of the circuit or the timer circuit, and a tripping section driven by the operation of the trigger circuit to perform a shearing operation.