KR101748727B1 - Leakage current detector - Google Patents

Leakage current detector Download PDF

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Publication number
KR101748727B1
KR101748727B1 KR1020150100629A KR20150100629A KR101748727B1 KR 101748727 B1 KR101748727 B1 KR 101748727B1 KR 1020150100629 A KR1020150100629 A KR 1020150100629A KR 20150100629 A KR20150100629 A KR 20150100629A KR 101748727 B1 KR101748727 B1 KR 101748727B1
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South Korea
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unit
signal
switching
capacitor
voltage
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KR1020150100629A
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Korean (ko)
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KR20170009127A (en
Inventor
김동현
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엘에스산전 주식회사
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Priority to KR1020150100629A priority Critical patent/KR101748727B1/en
Publication of KR20170009127A publication Critical patent/KR20170009127A/en
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
    • H02H3/16—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to fault current to earth, frame or mass
    • H02H3/162—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to fault current to earth, frame or mass for ac systems
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H1/00—Details of emergency protective circuit arrangements
    • H02H1/04—Arrangements for preventing response to transient abnormal conditions, e.g. to lightning or to short duration over voltage or oscillations; Damping the influence of dc component by short circuits in ac networks

Abstract

The present invention relates to an earth leakage breaker for detecting whether a leakage current is generated in a power line connecting an external power source and a load using a video current transformer, A switching unit including a capacitor charged or discharged by the received digital signal and outputting a voltage signal to be applied to the capacitor; a first switching unit for switching the first high signal when the signal outputted from the switching unit is higher than a first reference potential, Level signal to output a second high-level signal when the input signal generated by accumulating the second digital signal output from the comparison unit is equal to or higher than a predetermined second reference potential, The present invention relates to an earth leakage breaker.

Description

Leakage current detector

The present invention relates to a leakage detection circuit leakage breaker measured from a video current transformer, and more particularly, to a leakage circuit breaker that separates a noise current, a surge current, and the like from a leakage current.

The earth leakage breaker is a safety device that prevents the human body from electric shock and fire due to fire or arc by cutting off the corresponding power source in the circuit when the unbalanced current of the power source due to the leakage current generated from various electric wire lines exceeds the set value.

Fig. 1 shows a basic configuration of a conventional electrical leak detecting IC circuit 30.

First, the transducer 20 transmits magnetic flux information generated by the reciprocating current flowing in the plurality of lines connecting the external power source 10 and the load 50 to the electrical leak detecting IC circuit 30.

That is, in one of the plurality of lines, an input current flows to the load 50, and the other output current flows from the load 50. In a steady state (a state in which a short circuit is not caused) The magnetic fluxes generated by the respective currents cancel each other and the composite magnetic flux appearing in the electrical leak detecting IC circuit 30 becomes "0 ".

At this time, when an electric leakage occurs in an external device electrically connected to the plurality of lines, the combined magnetic field appearing on the line by the leakage current amount is deviated and appears in the electric leakage detecting IC circuit 30 by the deviation.

The voltage having the generated AC pattern due to the deviation is amplified at a predetermined ratio via the amplifier 31, and is converted into a digital signal through the A / D converter 32. The latch unit 33 located in the electrical leak detecting IC circuit 30 can transmit a control signal for operating the power OFF switch 40 based on the switched digital signal.

However, in such a conventional electrical leak detecting IC circuit 30, when an overcurrent of 6 to 7 times or more of the rated current flows from the outside, or a single overcurrent due to strong electromagnetic interference or electromagnetic interference flows through the line, The power supply to the load 50 is cut off.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the conventional art, and it is an object of the present invention to provide a power supply device, in which power is supplied when a change in the amount of current to a load sensed through a video current transformer is determined as a temporary surge current or a noise current, And an object of the present invention is to provide an electric leakage circuit breaker having a stable power supply by reducing the malfunction by turning off the corresponding power source.

Another object of the present invention is to provide a leakage circuit breaker having a control section for calculating a reference voltage differently according to a capacitance of a capacitor which determines a delay time of an external power supply cut-off operation for a signal suspected of being a leakage current.

According to an aspect of the present invention, there is provided an earth leakage breaker for detecting leakage current generated in a power source line connecting an external power source and a load using a video current transformer, A switching unit including a capacitor charged or discharged by the received digital signal and outputting a voltage signal to be applied to the capacitor; Level signal when the input signal generated by cumulatively accumulating the second digital signal output from the comparator is equal to or higher than a predetermined second reference potential, and a second high-level signal And a control unit for controlling the electric leakage circuit breaker by outputting the electric current.

Here, the amplifying unit, the switching unit, and the comparing unit may each include a plurality of comparators, and the first comparing unit of the plurality of comparing units may include a first amplifying unit of the plurality of amplifying units and a second switching unit of the plurality of switching units And a second comparing unit of the plurality of comparing units receives a signal processed by the second switching unit of the second amplifying unit and the plurality of switching units of the plurality of amplifying units, And can output the second digital signal.

The first comparing unit and the second comparing unit may be connected to one external device, and the first and second digital signals may be combined into one signal and input to the one external device.

The filter unit may further include a filter unit that connects the image current transformer and the amplifying unit, and the filter unit may include a low pass filter that removes a high frequency component of a current measured by the image current transformer.

The first amplifying unit outputs a third high level signal when the absolute value of the phase of the signal received from the video current transformer during a positive half wavelength is equal to or greater than a predetermined third reference potential, And output a fourth high level signal when the absolute value of the phase of the signal received from the image deflector during the negative half wavelength is equal to or greater than a predetermined fourth reference potential.

The switching unit may further include a switching unit connecting the amplifying unit and the comparing unit, wherein the switching unit includes a plurality of switching devices for charging or discharging the capacitor, A turn-on or turn-off operation can be performed by a digital signal to be output.

At this time, the comparator may receive the voltage of the capacitor, and may output a fifth high level signal when the voltage of the capacitor is equal to or higher than a predetermined reference potential.

In addition, the comparator may output a low level signal when the time corresponding to the wavelength of the received signal is less than a predetermined reference time.

According to an embodiment of the present invention, there is provided a signal processing apparatus for receiving a signal output from the comparator and removing a high frequency component of the received signal, And a low-pass filter.

At this time, one end of the external device is connected to the input terminal of the control unit, and the voltage of the capacitor constituting the low-pass filter may be input to the control unit.

The controller may further include a latch circuit for outputting a high level signal when the voltage of the capacitor reaches a predetermined reference voltage or more.

According to an embodiment, the earth leakage breaker according to the present invention may further include a trip driving unit electrically connected to the control unit to shut off the power supply to the load.

The controller may further include a thyristor circuit for outputting a signal for controlling the power-off operation of the trip driving unit based on the second high-level signal.

Here, the power supply voltage generating unit is connected to the amplifying unit, the comparing unit, the switching unit, and the control unit, respectively, and supplies the power to the amplifying unit, the comparing unit, the switching unit, .

The leakage circuit breaker according to the present invention determines the leakage current only when repeatedly and continuously measuring signals that may be suspected to be leakage currents and cuts off the power supply so as to prevent the power supply from being cut off due to the noise current and the surge current . Therefore, the power supply can be stably supplied to the load.

1 is a diagram showing a basic configuration of a conventional earth leakage breaker 30.
2 is a block diagram illustrating an earth leakage breaker according to an embodiment of the present invention.
3 is a diagram illustrating a signal processing operation of an amplifying unit of an earth leakage breaker according to an embodiment of the present invention.
4 is a diagram showing a signal processing operation of the switching unit of the present invention.
5 is a diagram showing a signal processing operation of the comparison unit of the present invention.
6 is a diagram illustrating a signal processing operation of the control unit according to the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings, wherein like reference numerals denote like or similar elements, and redundant description thereof will be omitted.

Further, the earth leakage breaker according to the present invention will be described in detail with reference to the drawings. The suffix "module" and " part "for components used in the following description are given merely for convenience of description, and do not give special significance or role in themselves. Accordingly, it should be noted that "module" and "part" may be used interchangeably.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

2 shows a basic configuration of an earth leakage breaker having a malfunction prevention function according to an embodiment of the present invention.

That is, an earth leakage breaker that detects whether a leakage current is generated in a power line connecting the external power source 200 and the load 250 using the image current transformer 210, detects an analog signal output from the image current transformer 210 A filter unit 221 for removing a specific frequency band among a plurality of frequency components of the received signal, an amplifying unit 222 for converting the analog signal from which the specific frequency has been removed into a corresponding digital signal, A switching unit 223 including a capacitor (not shown) charged or discharged according to the received digital signal and outputting a voltage signal to be applied to the capacitor; a signal output from the switching unit 223, A comparator 224 for outputting a first high level signal when the first reference level is equal to or higher than the first reference level and a comparator 224 for comparing the input signal generated by accumulating the first high level signal outputted by the comparator 224 with a predetermined second reference level, And a controller 240 for outputting a second high level signal to control the earth leakage breaker if the difference is greater than the predetermined value.

Here, the earth leakage breaker according to the present invention may include a plurality of electrical leak detecting IC circuits 220, and each of the electrical leak detecting IC circuits 220 may include the same internal components. However, they can receive different input voltages.

For example, the first electrical leak detecting IC circuit among the plurality of electrical leak detecting IC circuits 220 receives the positive voltage signal of the analog signal measured by the video current transformer 210, The second electrical leak detecting IC circuit can receive the negative voltage signal of the analog signal measured by the video current transformer 210. [

However, the first electrical leak detecting IC circuit and the second electrical leak detecting IC circuit may process different input signals in the same manner and output the same.

The first digital signal output by the first electrical leak detecting IC circuit and the second digital signal output by the second electrical leak detecting IC circuit may be combined with each other and input to the external device 230 as one input signal.

As another embodiment of the present invention, the electrical leak detecting IC circuit 220 may be composed of a plurality of internal elements having the same function.

That is, each of the amplifying unit 222, the switching unit 223, and the comparing unit 224 includes a plurality of comparators 224, and the first comparing unit (not shown) (Not shown) of the amplifying unit 222 and a signal processed by a first switching unit (not shown) of the plurality of switching units 223 to output a first digital signal, (Not shown) of the plurality of amplifying units 222 and a second amplifying unit (not shown) of the plurality of amplifying units 222 and a second switching unit And outputs the second digital signal.

Also, the first comparator (not shown) and the second comparator (not shown) are connected to one external device 230, and the first digital signal output from the first comparator (not shown) The second digital signals output by the second comparator (not shown) may be combined into one signal and input to the one external device 230.

First, the filter unit 221 may include a low-pass filter that removes a high-frequency noise signal of an alternating-current power supply signal flowing on a power supply line.

Thus, the signal having passed through the low-pass filter may include, for example, a low-frequency signal below a cut-off frequency, or a voltage signal generated by a leakage current or a single impulse current.

Next, the amplification unit 222 includes an operational amplifier (Op-amp), and can selectively amplify the voltage signal output from the filter unit 221. FIG.

The amplifying unit 222 includes a plurality of amplifying units (a first amplifying unit and a second amplifying unit), and a first amplifying unit (not shown) And a second amplifying unit (not shown) outputs a first high level signal when the absolute value of the phase of the input signal is greater than or equal to a predetermined first reference potential, Level signal when the absolute value of the corresponding phase is greater than or equal to a predetermined second reference potential.

The switching unit 223 for connecting the amplifying unit 222 and the comparing unit 224 may include a plurality of switching units (a first switching unit and a second switching unit) Each of the first switching unit (not shown) and the second switching unit (not shown) includes one capacitor (not shown) and a plurality of switching elements (not shown) charging or discharging the capacitor can do.

At this time, a plurality of switching elements included in each of the first switching unit and the second switching unit is turned on or off by a digital signal input from the amplifying unit (first amplifying unit and second amplifying unit) Operation can be started.

Next, as an embodiment of the present invention, the comparing unit 224 including an operational amplifier (Op-amp) may be configured with a plurality of comparing units (first comparing unit and second comparing unit).

The first comparator (not shown) may output a third high level signal when the capacitor voltage of the first switching unit, which changes with time, becomes equal to or higher than a predetermined third reference potential.

The second comparator (not shown) may output a fourth high level signal when the capacitor voltage of the second switching part, which changes with time, becomes equal to or higher than a predetermined fourth reference potential.

In addition, each of the first comparing unit and the second comparing unit may be configured such that when the time corresponding to the wavelength of the received signal is less than a preset reference time (first reference time, second reference time) Level signal, a second low-level signal).

Next, an external device 230 connecting between the comparators (the first comparator and the second comparator) and the controller 240 receives the signal output from the first comparator and the second comparator And a low pass filter (not shown) for receiving and removing high frequency components of the received signal.

Here, a capacitor (not shown) constituting the low-pass filter is charged by a high-level signal output from the comparators (first comparator and second comparator), and the comparator The comparator) can be discharged by the low level signal outputted from the comparator.

Accordingly, when the leakage current is continuously generated, the capacitor is repeatedly charged and discharged in a state that the capacitor is not completely discharged. When the voltage of the capacitor is increased to be equal to or higher than a predetermined reference potential, the capacitor (not shown) The control unit 240 may output a high level signal to start interrupting the external power supply.

The control unit 240 includes a latch circuit (not shown) for outputting the high level signal, and a thyristor circuit (not shown) for controlling the operation of a trip driving unit (not shown) (Not shown).

That is, the high level signal from the control unit 240 turns on a thyristor circuit (not shown) connected to the latch circuit (not shown), and the thyristor circuit (not shown) (Silicon Controlled Rectifier, SCR).

That is, the thyristor circuit (not shown) may allow the flow of current to the trip coil of the trip driving unit (not shown) to operate the switch on the line to cut off the leakage current flowing to the load 240.

The controller 240 stores a predetermined reference voltage value and compares the stored reference voltage value with a voltage input through the external device 230. The controller 240 may be a microcomputer, Or in the form of various controllers.

3 is a diagram illustrating a signal processing operation of the amplifying unit 222 of the earth leakage breaker according to an embodiment of the present invention.

Here, the amplifying unit (first amplifying unit and second amplifying unit) compares the stored reference voltages V REF1 and V REF2 with the analog signal received from the filter unit 221, and selectively amplifies the digital signal And output it.

In an embodiment of the present invention, the first amplifying unit (not shown) may be configured such that an absolute value of a phase corresponding to a half wavelength of a positive half of a signal received from the video current transformer 210 is greater than a predetermined first reference voltage V REF1 ), The second amplifying unit (not shown) amplifies the high level signal and outputs the absolute value of the phase corresponding to the half wavelength of the negative signal of the signal received from the video current transformer 210, 2 < / RTI > reference voltage V REF2 .

4 is a diagram showing a signal processing operation of the switching unit 223 of the present invention. Here, the switching unit (the first switching unit and the second switching unit) receives the digital signals (the first digital signal and the second digital signal) output from the amplifying units (the first amplifying unit and the second amplifying unit) And can output the voltage of the capacitor charged or discharged by the received digital signal (first digital signal, second digital signal).

Here, the switching unit (the first switching unit and the second switching unit) may charge or discharge the capacitor through an external power source using a plurality of switching devices operated according to the input signal V input .

Here, the first region (V output1) is the discharge time (t 1) of shows the signal corresponding to the charge time (t 1) of the capacitor the second region (V output2) of the output signal is the capacitor of the output signal ≪ / RTI >

5 is a diagram showing a signal processing operation of the comparison unit 224 according to the present invention.

In an embodiment of the present invention, when the received input signal is a signal larger than a predetermined reference voltage (V REF3 ), the comparison unit (first comparison unit and second comparison unit) may output a corresponding high level signal have.

For example, each of the first comparator and the second comparator may output a low level signal because the input signal corresponding to the first time period t 1 has a phase smaller than the reference voltage V REF3 .

In addition, since each of the first comparing unit and the second comparing unit has a phase in which the input signal in the second time zone (t 2 ) and the third time zone (t 3 ) is larger than the reference voltage (V REF3 ) A second comparator) can output a high level signal.

In addition, each of the first comparing unit and the second comparing unit may be configured such that the input signal of the fourth time zone (t 4 ) has a phase smaller than the reference voltage (V REF3 ) and is for a time shorter than a predetermined time period, Level signal.

6 is a diagram illustrating a signal processing operation of the control unit 240 according to the present invention.

Here, the control unit 240 may output a high level signal at a time point t 1 when the output signal from the external device 230 is greater than a predetermined reference voltage V REF4 .

Here, the signal output from the external device 230 and input to the controller 240 may indicate a varying capacitor (not shown) voltage of the external device 230.

The high level signal output by the controller 240 allows a current to flow through the trip coil of the trip driver (not shown) to operate a switch (not shown) on the line to generate a leakage current Can be blocked.

30: Leakage detection IC circuit (conventional) 230: External element
200: external power source 240:
210: Video current transformer 250: Load
220: Leakage detection IC circuit (present invention)

Claims (14)

1. An earth leakage breaker for detecting a leakage current generated in a power line connecting an external power source and a load using a video current transformer,
An amplifier for converting an analog signal output from the image transformer into a corresponding digital signal and outputting the digital signal;
A switching unit including a capacitor charged or discharged by the received digital signal, and outputting a voltage signal to the capacitor;
A comparator for outputting a first high level signal when the signal output from the switching unit is equal to or higher than a predetermined first reference potential;
A control unit for outputting a second high level signal when the input signal generated by accumulation of the second digital signal output from the comparison unit is equal to or higher than a predetermined second reference potential and controlling the earth leakage breaker;
And a switching unit connecting the amplifying unit and the comparing unit,
Wherein the switching unit includes a plurality of switching elements for charging or discharging the capacitor, wherein each of the plurality of switching elements performs a turn-on or a turn-off operation by a digital signal outputted from the amplifying unit . The method according to claim 1,
Wherein the first amplifying unit, the switching unit, and the comparing unit are each composed of a plurality of comparators, and the first comparing unit of the plurality of comparing units performs the first switching unit process among the first amplifying unit and the plurality of switching units Receives a signal and outputs a first digital signal,
Wherein the second comparing unit of the plurality of comparing units receives the signal processed by the second amplifying unit and the second switching unit of the plurality of switching units and outputs the second digital signal, . 3. The method of claim 2,
Wherein the first comparing unit and the second comparing unit are connected to one external device so that the first and second digital signals are combined into one signal and input to the one external device. The method according to claim 1,
Further comprising a filter unit connecting the image transformer and the amplifying unit,
Wherein the filter unit includes a low-pass filter for removing a high-frequency component of a current measured by the image current transformer. 3. The method of claim 2,
Wherein the first amplifying unit outputs a third high level signal when the absolute value of the phase of the signal received from the video current transformer during the positive half wave period is equal to or greater than a predetermined third reference potential,
Wherein the second amplifying unit outputs a fourth high level signal when the absolute value of the phase of the signal received from the video current transformer during the negative half wavelength is equal to or greater than a predetermined fourth reference potential. delete The apparatus according to claim 1,
And a fifth high level signal is output when the voltage of the capacitor is higher than a predetermined reference potential. 8. The apparatus according to claim 7,
And outputs a low level signal when the time corresponding to the wavelength of the received signal is less than a predetermined reference time. The method according to claim 1,
And an external device for connecting the comparison unit and the control unit,
Wherein the external device includes a low-pass filter that receives a signal output from the comparison unit and removes a high-frequency component of the received signal. 10. The semiconductor device according to claim 9, wherein one end of the external device
Wherein a voltage of a capacitor constituting the low-pass filter is connected to the input of the control unit, and the voltage of the capacitor constituting the low-pass filter is input to the control unit. 11. The apparatus according to claim 10,
And a latch circuit for outputting a high level signal when the voltage of the capacitor becomes equal to or higher than a predetermined reference voltage. The apparatus according to claim 1, further comprising:
Further comprising a trip driving unit for shutting off power supplied to the load. 13. The apparatus according to claim 12,
And a thyristor circuit for outputting a signal for controlling the power-off operation of the trip driving unit based on the second high-level signal. The method according to claim 1,
A comparator, a switching unit, and a control unit,
Further comprising a power supply voltage generator for varying the external power supply to supply different power supplies to the amplifying unit, the comparing unit, the switching unit, and the control unit.
KR1020150100629A 2015-07-15 2015-07-15 Leakage current detector KR101748727B1 (en)

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KR101872797B1 (en) 2017-05-18 2018-06-29 두산중공업 주식회사 Digital signal output device
KR102270144B1 (en) * 2020-07-03 2021-06-29 (주)재신정보 Medium-sensitivity three-phase earth leakage circuit breaker and earth leakage alarm device to prevent inconvenience unnecessarily blocked by instantaneous distortion waveforms by applying a time-order comparison algorithm in the instantaneous earth leakage current

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