KR101527366B1 - Arc detection circuit by contact failure - Google Patents

Abstract

The present invention is to provide a circuit for detecting arc due to contact failure, capable of detecting arc current up to arc current below 10 milliamperes by detecting arc voltage when arc is generated by contact failure, capable of detecting arc voltage due to contact failure using a distribution capacity to ground, and capable of detecting arc voltage when arc is continuously generated over a predetermined time. According to an embodiment of the present invention, a circuit for detecting arc due to contact failure is a circuit for detecting arc generated by contact failure between lines by being arranged at a back end part of an earth leakage breaker for in-house wiring, and comprises: a rectifying unit to rectify arc pulse current by contact failure; an arc voltage detection unit to detect arc voltage by the arc pulse current passing through the rectifying unit; a high-frequency pass filter combined with a front end or a back end of the arc voltage detection unit; a control signal generation unit to generate a relay driving control signal using the arc voltage detected by the arc voltage detection unit; and a relay to electrically connect a power line to a ground line in the in-house wiring by being controlled by the relay driving control signal. The control signal generation unit includes: a pulse signal generation unit to generate a predetermined pulse width by receiving the arc voltage via an input terminal; a pulse delay signal generation unit to generate a pulse delay signal when the pulse signal outputted from the pulse signal generation unit is higher than or equal to a predetermined number; and a driving control signal generation unit to generate a relay driving control signal to operate the relay using the pulse delay signal.

Description

[0001] ARC DETECTION CIRCUIT BY CONTACT FAILURE [0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an arc detection circuit due to contact failure, and more particularly to an arc detection circuit which detects an arc or a spark due to a contact failure in an electric circuit, To an arc detection circuit.

About 30% of all fires are electric fires, more than 60% of them are caused by fault of wiring system. Most of fires due to fault of wiring system are caused by overheating due to contact failure, faulty arc or line insulation It is a tracking / arc accident.

In general, there is a problem that such an accident of the wiring system can not be prevented and prevented. In particular, the insulation failure caused by the contamination or carbonization of the line insulation is a kind of load current, so it can not be blocked by a conventional circuit breaker. Checking is also unrealistic.

In the case of such a line-to-line fault, that is, a line-to-line short-circuit, the arc discharge of a minute thread is continued only in a dark state because of a slight current arc discharge. It changes.

Also, due to the nature of the arc discharge, a discharge is caused along a trajectory in which a current can flow well. In other words, the shape of the lightning arc is similar to the twisted shape of a twig. In the early stage of the tracking arc, the arc current is too small to be detected by a general arc detection technique. In a general arc breaker, the shape of the current waveform flowing to the load, the magnitude of the distortion wave current , It is impossible to detect a tracking current, which is a minute current, because it is indistinguishable from the noise included in the power when the arc current is small.

The current certification of the current arc breaker or arc alarm is based on the load current of 5 amperes [A]. However, the 5 amps [A] is a very large current value, which means that the carbonization of the insulation has progressed to a considerable level due to the poor contact, and does not correspond to the current value to prevent electric fire.

On the other hand, Korean Patent No. 0914999, an arc detecting circuit breaker of a low-voltage indoor arc furnace maintains a linear characteristic in a low frequency and a high frequency range, prevents a damage including a fire by a parallel arc current, A current transformer CT for detecting a parallel arc current using a current as a detection parameter; An integrating unit for integrating a signal detected by the current sensor; A filter unit for removing high frequency noise from the signal integrated by the stochastic integration unit and limiting the current; A rectifying section for full-wave rectifying a signal passing through the upper filter section; An amplifying unit for amplifying a signal rectified by the rectifying unit; A converter for converting a current amplified by the amplifying unit into a voltage; An SCR in which a current signal is directly applied to a gate, And a trip coil connected to the anode side of the upper SCR and operating the circuit breaker to shut off the circuit.

Also, the arc detection apparatus of a low-voltage indoor converter disclosed in Korean Patent Laid-Open Publication No. 2013-0095947 includes a CT installed between an external voltage input line and a lower end; An arc detector for detecting a current due to an arc defect from the CT; A voltage phase detector for detecting a phase of a voltage currently input to the power supply line; And comparing the detected voltage phase with a current to determine an arc characteristic when an arc is generated in a current in a voltage phase of the arc recognition interval and determines the arc characteristic as a load characteristic when an arc is generated in a current phase in a voltage phase of the other section .

However, since an apparatus for detecting an arc by detecting a current as described above uses a current transformer (CT), when magnetic saturation occurs in the current transformer core due to the load current flowing through the current transformer, the inductance value It is impossible to measure normal current because it is different.

Korean Patent Registration No. 10-0914999 Arc detection circuit breaker for low-voltage indoor arc furnace Korean Unexamined Patent Application Publication No. 10-2013-0095947 Arc detection apparatus and method

An object of the present invention is to provide an arc detection circuit by contact failure capable of detecting an arc voltage when an arc occurs due to a contact failure.

Another object of the present invention is to provide an arc detection circuit which can detect an arc current of about 10 milliamperes by detecting an arc voltage when an arc occurs due to a contact failure.

It is still another object of the present invention to provide an arc detection circuit which can detect an arc voltage due to a contact failure using a distribution capacity between lands.

It is still another object of the present invention to provide an arc detection circuit which can detect an arc voltage when an arc is continuously generated for a predetermined time or longer.

An arc detection circuit according to the first invention of the present application is a circuit which is arranged at the rear end of a ground fault interrupter of indoor wiring and detects an arc caused by a contact failure occurring between lines, A rectifying part for a rotating operation power source including a rectifying part; An arc voltage detector for detecting an arc voltage caused by the arc pulse current passing through the rectifying part; A high-frequency pass filter coupled to a front end or a rear end of the arc voltage detection unit; A control signal generator for generating a relay operation control signal by using an arc voltage detected by the arc voltage detector; And a relay controlled by the relay operation control signal and electrically connecting a ground line of the indoor wiring to a power supply line, wherein the control signal generator receives the arc voltage at an input terminal and generates a predetermined pulse width A pulse signal generator; A pulse delay signal generator for generating a pulse delay signal when the number of pulse signals output from the pulse signal generator is equal to or greater than a predetermined number; And an operation control signal generator for generating a relay operation control signal for operating the relay using the pulse delay signal.

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Preferably, the control signal generator receives the arc voltage at the input terminal and operates the buzzer when the arc voltage is maintained for a predetermined time or more, thereby continuously or intermittently ringing the alarm sound, And generates the relay operation control signal when it sounds for a predetermined time or intermittently reaches a predetermined number of times.

The arc detection circuit according to the second invention of the present application is a circuit which is arranged at the rear end of an earth leakage breaker of an indoor wiring and detects an arc due to a contact failure occurring between lines, A rectifying part; A pulse signal coupling unit configured to recognize a distribution capacitance existing between the arc detection circuit including the power source and the ground G as an arc voltage of a high frequency when an arc is generated due to the contact failure; A signal amplifying unit that is switched to an arc voltage of a high frequency applied through the pulse signal combining unit and amplifies the arc pulse voltage; A high-frequency pass filter coupled to a front end or a rear end of the arc voltage detection unit; A control signal generator for generating a relay operation control signal using an arc voltage output from the signal amplifying unit; And a relay controlled by the relay operation control signal to electrically connect the ground line and the power line of the indoor wiring.

Preferably, the system further includes a buzzer for controlling and alarming an alarm control signal generated according to the pulse delay signal.

Preferably, the pulse signal generator is a monostable multivibrator, and the operation control signal generator is an unstable multivibrator.

Preferably, the apparatus further includes a sensitivity adjusting unit coupled to an input side of the control signal generating unit and configured to adjust an arc pulse reference value including a variable resistance to recognize the arc voltage as an arc pulse.

According to the present invention, an arc voltage can be detected when an arc is generated due to a contact failure, and an arc current of less than 10 milliamperes can be detected by detecting an arc voltage when an arc is generated due to a contact failure. The arc voltage due to the contact failure can be detected, and the arc voltage can be detected when an arc is continuously generated for a predetermined time or more.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is an overall circuit diagram for arc detection by contact failure according to a first embodiment of the present invention; Fig.
2 is an overall circuit diagram for arc detection by contact failure according to a second embodiment of the present invention, and Fig.
3 is an overall circuit diagram for arc detection by contact failure according to the third embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to this, terms and words used in the present specification and claims should not be construed as limited to ordinary or dictionary terms, and the inventor should appropriately interpret the concepts of the terms appropriately It should be interpreted in accordance with the meaning and concept consistent with the technical idea of the present invention based on the principle that it can be defined. Therefore, the embodiments described in this specification and the configurations shown in the drawings are merely the most preferred embodiments of the present invention and do not represent all the technical ideas of the present invention. Therefore, It is to be understood that equivalents and modifications are possible.

1 is an overall circuit diagram for arc detection by contact failure according to the first embodiment of the present invention.

The arc detection circuit according to the first embodiment of the present invention includes an indoor wiring connection portion 101, a high-frequency pass filter 105, a rectifying portion 110, a smoothing portion 115, a constant voltage portion 120, A pulse signal combining unit 130, a unidirectional current passing unit 135, a sensitivity adjusting unit 140, a pulse signal generating unit 150, a pulse signal delay unit 155, an operation control signal generating unit 150, An operation control switch 163, an alarm unit 165, a relay unit 170, a leakage current restricting unit 175, and a leakage current path generating unit 180.

In the first embodiment of the present invention, an alarm is generated by operating the alarm unit 165 using the high-frequency impulse arc voltage applied to the arc voltage detection unit 125, or by operating the relay unit 170 to flow a leakage current, Operate the earth leakage breaker installed in the unit.

Hereinafter, the configuration and operation of each unit will be described.

The indoor wiring connection portion 101 is configured to be coupled to the indoor wiring, and can be detachably coupled to the outlet, for example, in the form of a plug. Further, according to another embodiment of the present invention, it can be fixedly coupled with the indoor wiring. On the other hand, for example, the contact failure may occur between all the wires electrically connected at the rear end of the earth leakage breaker of the indoor wiring, and may be caused by carbonization of the insulation coating, and the insulation coating may peel off by using the wire for a long time It may also be caused by insulation failure. According to another example, the contact failure may occur when the plug is loosely engaged with the receptacle (receptacle) at the rear end of the earth leakage breaker of the indoor wiring.

Here, "L" means two lines and "G" means ground line. That is, any one of the two lines is the ground line, but since it is not known which line is the ground line, it is implemented as shown.

The high-frequency pass filter 105 includes a resistor R10 and a capacitor C8 connected in parallel. The capacitor C8 passes a pulse component of current input through the AC power supply connection terminal L and blocks the DC component , And the resistor R10 discharges the electric charge charged in the capacitor C8.

The rectifying unit 110 is coupled to the output side of the high-frequency filter 105 and rectifies the arc voltage output from the high-frequency filter 105. According to an embodiment of the present invention, the rectifying part 110 is in the form of a bridge diode, but is not limited thereto, and any structure can be used for rectifying the AC power.

The smoothing unit 115 includes a capacitor C7 connected in parallel at both ends of the rectifying unit 110 and the capacitor C7 smoothes the voltage output from the rectifying unit 110. [

The constant voltage unit 120 includes a zener diode Z1 connected in parallel with the smoothing unit 115 and maintains the output voltage of the rectifier unit 110 within a predetermined range.

The arc voltage detection unit 125 may be a constant-temperature coefficient device PTC1 that generates an arc voltage based on an arc pulse current that has passed through the smoothing unit 115. [

The pulse signal combiner 130 includes a resistor R11 and a capacitor C9 connected in series to the output of the arc voltage detector 125. The pulse signal combiner 130 combines the arc pulse voltage of the high frequency component passed through the arc voltage detector 125 .

The unidirectional current passing portion 135 is coupled between the output side of the pulse signal coupling portion 130 and the other end of the capacitor C7 in the arc voltage holding portion 115, The smoothing part 115 is prevented from flowing.

The pulse signal generator 150 receives an arc voltage of a high frequency component applied to the arc voltage detector 125 to an input terminal and generates a pulse signal having a predetermined pulse width. Here, according to an embodiment of the present invention, the pulse signal generator 150 may be a monostable multivibrator. The sensitivity adjuster 140 coupled to the input side of the pulse signal generator 150 can adjust the arc pulse reference value including the variable resistance to detect the arc voltage to be detected as an arc pulse. the arc pulse current of [mA] can be detected. Although not shown, the oscillation time constant of the pulse signal generator 150 may be varied depending on the size of the resistor and the capacitor coupled to the control terminal of the internal switching device.

The pulse delay signal generation unit 155 generates a pulse delay signal when the pulse signal output from the pulse signal generation unit 150 is equal to or more than a predetermined number or repeats over a predetermined length. That is, when the pulse signal is equal to or more than a predetermined number or is repeated for a predetermined length or more, charging is completed in the capacitor C6 to generate a pulse delay signal.

When the operation control signal generating unit 160 generates an operation control signal for operating the buzzer 165 using the pulse delay signal, the operation control switches S1 and 163 operate to set the alarm buzzer 165 Or the relay coil of the relay unit 170 is operated. According to another embodiment of the present invention, a plurality of switches may be disposed to operate the buzzer 165 and the relay unit 170 at the same time. When the relay unit 170 operates and a leakage current flows, an earth leakage breaker (not shown) provided in the indoor switchboard operates. According to an embodiment of the present invention, the operation control signal generator 160 may be implemented as an unstable multivibrator and may operate the buzzer 165 intermittently.

According to another embodiment of the present invention, the pulse delay signal generation unit 155 and the operation control signal generation unit 160 may be implemented by a digital circuit including a counter. If the number of pulse signals is more than a predetermined number, The counter outputs an operation control signal to continuously operate the buzzer 165. [

The leakage current limiting unit 175 includes a PTC element connected in series with the relay contact. When the relay is operated in the event of an overload or short-circuit, leakage current flows to the ground. If the earth leakage breaker is broken, If not installed, there is a risk of fire due to overheating if a large amount of leakage current continues to flow. Therefore, when the temperature of the PTC element flows due to the leakage current, the resistance rapidly increases, and the leakage current can be rapidly reduced. According to one embodiment of the present invention, only one PTC element is used, but the present invention is not limited thereto. According to another embodiment, a plurality of PTC elements may be used. According to another embodiment, a PTC element and an NTC element may be used And according to another embodiment, it is natural that the NTC element can be used singularly or plurally.

The leakage current path generating unit 180 forms a path through which a leakage current flows when the relay 170 operates between the ground line G and the two lines L. [ According to an embodiment of the present invention, the leakage current path generation unit 180 includes a one-way switching element connected in the same direction between a ground side line G and two lines L, respectively. For example, a diode having a forward direction may be disposed on the side of the line G on the ground side to the two lines L side. Or a diode having a forward direction from the two line L side to the ground line G side may be disposed. According to another embodiment of the present invention, the power supply line H and the ground line G are short-circuited under the condition of determining which of the two lines L is the power supply line H, (170) is operated, a leakage current flows.

On the other hand, the arc detection device due to contact failure according to the present invention can be miniaturized by a simple circuit and can be a power plug type, and can be built in a multi-socket or embedded in an electric appliance.

2 is an overall circuit diagram for arc detection by contact failure according to a second embodiment of the present invention.

The arc detection circuit due to contact failure according to the second embodiment of the present invention includes an indoor wiring connection part 201, a high frequency filter 205, a rectifying part 210, a smoothing part 215, a constant voltage part 220, A first signal amplifying unit 235, a second signal amplifying unit 240, a pulse signal generating unit 250, a pulse signal delaying unit 255, and an inrush current preventing unit 225, a pulse signal combining unit 230, An operation control switch 263, an alarm unit 265, a relay unit 270, a leakage current restricting unit 275, and a leakage current path generation unit 280. The operation control signal generation unit 260 includes an operation control signal generation unit 260,

In the second embodiment of the present invention, when an arc pulse is generated due to a contact failure, an alarm is generated by operating the alarm unit 165 using the distributed capacitive arc voltage existing between the pulse signal coupling unit 230 and the ground, The relay unit 170 is operated to flow a leakage current to operate the earth leakage breaker installed in the indoor inlet unit.

Hereinafter, the configuration and operation of each unit will be described.

The second embodiment of the present invention shown in FIG. 2 is similar to that of the first embodiment of the present invention shown in FIG. 1, so that different parts will be mainly described.

The inrush current prevention part 225 includes a constant temperature coefficient element PTC1 disposed between the in-house wiring interconnection part 101 and the rectification part 210 to protect the circuit from the inrush current or surge applied from the power supply part.

The pulse signal coupling unit 230 is an antenna formed to recognize a distribution capacitance present between the ground G and the ground G when a arc is generated due to a contact failure as a high frequency.

The first signal amplifying unit 235 includes a transistor TR1 which is switched to a high frequency arc pulse applied through the pulse signal combining unit 230 and amplifies the arc pulse first.

The second signal amplifying unit 240 includes a transistor TR2 that is switched to a high frequency arc pulse and amplifies the arc pulse secondarily. Here, the capacitor C3 and the resistor R3 between the transistor TR1 and the transistor TR2 which are not illustrated act as a high-pass filter (HPF) suitable for passing a high-frequency signal.

The pulse signal generator 250 receives the high frequency arc pulse signal applied through the pulse signal combiner 230 at the input side and generates a pulse signal having a predetermined pulse width.

3 is an overall circuit diagram for arc detection by contact failure according to the third embodiment of the present invention.

The arc detection circuit due to contact failure according to the third embodiment of the present invention includes an indoor wiring connection portion 301, a high-frequency pass filter 305, a rectification portion 310, a smoothing portion 315, a constant voltage portion 320, An AC voltage detection unit 325, a pulse signal coupling unit 330, a unidirectional current passing unit 335, a sensitivity adjusting unit 340, a microcomputer 350, a reset switch 351, a PL 352, an alarm unit 365, A relay unit 370, a leakage current restricting unit 375, and a leakage current path generating unit 380. Here, X1 is an oscillation element for clock generation.

In the third embodiment of the present invention, the functions of the monostable multivibrator of the pulse signal generator 150 of the first embodiment and the unstable multivibrator of the operation control signal generator 160 are performed by the microcomputer 350 .

The microcomputer 350 receives the arc voltage of the high-frequency impulse component applied to the arc voltage detector 325 to the input terminal, and when the arc voltage continues for a predetermined time or more, the buzzer operates to continuously or intermittently sound an alarm sound . The relay can be operated when the alarm sound continuously sounds for a predetermined time or intermittently reaches a predetermined number of times. As a result, it is possible to prevent an alarm sound or a relay from operating due to temporary electrical noise.

The reset switch 351 is a structure for deleting the interrupting operation record stored in the memory of the microcomputer 350.

The PL 352 can be used as a monitoring lamp or as a lamp for displaying a breaking operation record. Even when the power of the microcomputer is turned off, the microcomputer can memorize the operation history (operation history) .

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. It will be understood that various modifications and changes may be made without departing from the scope of the appended claims.

101: Indoor wiring connection part 105: High-frequency pass filter
110: rectification part 115: smooth part
120: constant voltage section 125: arc voltage detecting section
130: Pulse signal coupling unit 135: Unidirectional current passing unit
140: sensitivity adjusting unit 150: pulse signal generating unit
155: Pulse signal delay unit 160: Operation control signal generation unit
163: Operation control switch 165:
170: Relay unit 175: Leakage current limiting unit
180: Leakage current path generation unit

Claims (9)

In an arc detection circuit which is disposed at the rear end of a ground fault interrupter of an indoor wiring and which is caused by a contact failure occurring between lines,
A rectification section for a rotation operation power source including an arc pulse current due to the contact failure;
An arc voltage detector for detecting an arc voltage caused by the arc pulse current passing through the rectifying part;
A high-frequency pass filter coupled to a front end or a rear end of the arc voltage detection unit;
A control signal generator for generating a relay operation control signal by using an arc voltage detected by the arc voltage detector; And
And a relay controlled by the relay operation control signal to electrically connect the ground line and the power line of the indoor wiring
Wherein the control signal generator comprises:
A pulse signal generator for receiving the arc voltage at an input terminal and generating a predetermined pulse width;
A pulse delay signal generator for generating a pulse delay signal when the number of pulse signals output from the pulse signal generator is equal to or greater than a predetermined number; And
And an operation control signal generator for generating a relay operation control signal for operating the relay using the pulse delay signal,
The arc detection circuit comprising:
delete The apparatus according to claim 1,
The arc voltage is inputted to the input terminal, and when the arc voltage is maintained for a predetermined time or longer, the buzzer can be operated to continuously or intermittently sound an alarm sound, and the alarm sound continuously sounds for a predetermined time or intermittently, The arc detection circuit generates the relay operation control signal.
In an arc detection circuit which is disposed at the rear end of a ground fault interrupter of an indoor wiring and which is caused by a contact failure occurring between lines,
A rectifying unit for rectifying the AC voltage between the lines;
A pulse signal coupling unit configured to recognize a distribution capacitance existing between the arc detection circuit including the power source and the ground G as an arc voltage of a high frequency when an arc is generated due to the contact failure;
A signal amplifying unit that is switched to an arc voltage of a high frequency applied through the pulse signal combining unit and amplifies the arc pulse voltage;
A high-frequency pass filter coupled to a front end or a rear end of the arc voltage detection unit;
A control signal generator for generating a relay operation control signal using an arc voltage output from the signal amplifying unit; And
And a relay for electrically connecting the ground line and the power supply line of the indoor wiring under the control of the relay operation control signal,
The arc detection circuit comprising:
The method according to claim 1 or 3,
Further comprising a buzzer to be controlled by an alarm control signal generated in accordance with the pulse delay signal.
The method according to claim 1 or 4,
Wherein the pulse signal generator is a monostable multivibrator, and the operation control signal generator is an unstable multi-vibrator.
The method according to claim 1 or 3,
Further comprising a one-way switching element connected in the same direction between the ground side line (G) and the two lines of the line (L).
The method according to claim 1 or 3,
An arc detection circuit due to a contact failure in which a leakage current path is generated due to an electrical short circuit between the power supply line (H) and the ground line (G).
The method according to claim 1 or 3,
And a sensitivity adjusting unit coupled to an input side of the control signal generating unit and configured to adjust an arc pulse reference value including a variable resistance to recognize the arc voltage as an arc pulse.

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