KR20170109939A - Electric leakage detecting circuit for electric leakage circuit breaker - Google Patents

Electric leakage detecting circuit for electric leakage circuit breaker Download PDF

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Publication number
KR20170109939A
KR20170109939A KR1020160034184A KR20160034184A KR20170109939A KR 20170109939 A KR20170109939 A KR 20170109939A KR 1020160034184 A KR1020160034184 A KR 1020160034184A KR 20160034184 A KR20160034184 A KR 20160034184A KR 20170109939 A KR20170109939 A KR 20170109939A
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KR
South Korea
Prior art keywords
circuit
current
detection signal
leakage
ground fault
Prior art date
Application number
KR1020160034184A
Other languages
Korean (ko)
Inventor
정현영
Original Assignee
엘에스산전 주식회사
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Filing date
Publication date
Application filed by 엘에스산전 주식회사 filed Critical 엘에스산전 주식회사
Priority to KR1020160034184A priority Critical patent/KR20170109939A/en
Publication of KR20170109939A publication Critical patent/KR20170109939A/en

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    • G01R31/025—
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R15/00—Details of measuring arrangements of the types provided for in groups G01R17/00 - G01R29/00, G01R33/00 - G01R33/26 or G01R35/00
    • G01R15/14—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks
    • G01R15/18—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks using inductive devices, e.g. transformers
    • G01R31/06—
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
    • G01R31/327—Testing of circuit interrupters, switches or circuit-breakers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H83/00—Protective switches, e.g. circuit-breaking switches, or protective relays operated by abnormal electrical conditions otherwise than solely by excess current
    • H01H83/02—Protective switches, e.g. circuit-breaking switches, or protective relays operated by abnormal electrical conditions otherwise than solely by excess current operated by earth fault currents
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H1/00—Details of emergency protective circuit arrangements
    • H02H1/0007—Details of emergency protective circuit arrangements concerning the detecting means
    • 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

Abstract

The present invention provides an electrical leak detecting circuit for an earth leakage breaker capable of detecting the occurrence of a ground fault current. The electrical leak detecting circuit of an earth leakage breaker according to the present invention comprises: a video current transformer for detecting a ground fault current and outputting a detection signal; A first circuit having a first winding portion wound on one side of the video current transformer and receiving the detection signal from the first winding portion and delivering the detection signal; And a second circuit having a second winding portion wound on the other side of the image deflector and connected to the first circuit to classify and flow the current of the first circuit when a ground fault current is generated.

Description

TECHNICAL FIELD [0001] The present invention relates to an electrical leak detection circuit for an electric leakage circuit breaker,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric leakage circuit breaker (hereinafter, abbreviated as an electric leakage breaker), and more particularly, to an electric leakage detecting circuit of an electric leakage breaker capable of detecting current by reducing saturation of a voltage transformer with respect to a ground fault current.

1 is a circuit diagram of an electrical leak detecting circuit for an earth leakage breaker according to the related art.

FIG. 1 is a block diagram showing a configuration of an electrical leak detecting circuit of a ground fault circuit breaker according to the related art, FIG. 2 is a waveform diagram of a ground fault current in a permissible range of a leakage current detecting circuit of a ground fault circuit breaker according to the prior art, Is a waveform diagram of a leakage current (ground fault current) at the occurrence of a leakage current exceeding an allowable range in the leakage detection circuit of the leakage circuit breaker according to the related art.

1, the electric leakage detecting circuit of the earth leakage breaker according to the related art can be configured to include the video current transformer 1, the voltage generating resistor 2 and the detecting circuit unit 3. [

The illustrated video transformer 1 is a ring shaped core type video current transformer and is provided with at least one of the three phase power lines with an electrical leak detecting object line (for example, three-phase power line) The leakage current detection signal is provided by the current induced in the winding wound on the annular core in the event of a short circuit in the power line.

The voltage forming resistor (2) converts the current signal induced in the windings wound on the video current transformer (1) into a voltage signal by a resistor and provides it to the detection circuit part (3).

The detection circuit unit 3 can determine whether or not a leakage current is generated by reading a voltage formed across the voltage-generating resistor 2 and comparing it with a reference voltage for determining an electrical leak.

The detection circuit section 3 may be composed of an integrated circuit and may include an operational amplifier for comparison and amplification.

The leakage current waveform provided as a voltage formed across the voltage-generating resistor 2 may be referred to FIG.

As can be seen from Fig. 2, the operational amplifier output waveform at the time of the occurrence of the leakage current within the allowable range can sufficiently ensure the pulse width, so that the detection circuit section 3 can determine whether or not a short circuit has occurred.

However, as can be seen from Fig. 3, a ground fault current exceeding the allowable range, for example, a ground fault current waveform provided as a voltage formed across the voltage-generating resistor 2 in the occurrence of a ground fault current, The pulse width of the output waveform is too narrow and it is impossible to determine whether or not a leakage current has occurred in the detection circuit unit 3. [

For this reason, in the current characteristic region in which the frame current transformer 1 can detect one of the operating characteristic regions, the linear characteristic is shown. However, for the ground fault current whose leakage current exceeds a predetermined level, the frame current transformer 1 is saturated The detection current waveform has a nonlinear characteristic like the grounding current waveform in Fig. 3, and it is difficult to determine whether or not a leakage current occurs in such a saturation region.

Therefore, there is a problem that the leakage detection circuit of the earth leakage breaker according to the related art can not detect the occurrence of the ground fault current.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide an electrical leak detecting circuit for an earth leakage breaker capable of detecting the occurrence of a ground fault current.

An object of the present invention is to provide an electrical leak detecting circuit for a ground fault circuit breaker,

A video current transformer for detecting a ground fault current and outputting a detection signal;

A detection circuit unit for detecting a short circuit based on the detection signal;

A first circuit having a first winding part wound on one side of the video current transformer and transmitting the detection signal received from the first winding part to the detection circuit part; And

And a second circuit having a second winding portion wound on the other side of the image deflector and connected to the first circuit to classify and flow the current of the first circuit when a ground fault current is generated, Lt; / RTI > circuit.

According to a preferred aspect of the present invention, in the electrical leak detecting circuit for an earth leakage breaker according to the present invention, the detecting circuit unit includes: an operational amplifier circuit unit connected to the first circuit and operationally amplifying a detection signal transmitted by the first circuit; And a leakage determination circuit unit connected to the operational amplification circuit unit for comparing the operational amplified detection signal with a predetermined electric leak judgment reference value to determine whether or not a electric leakage has occurred.

According to another preferred aspect of the present invention, the electrical leak detecting circuit of the earth leakage breaker according to the present invention further comprises a resistor connected in parallel to both ends of the first winding section and providing a detection signal as a voltage signal.

According to another preferred embodiment of the present invention, in the electrical leak detecting circuit for an earth leakage breaker according to the present invention, a trigger is provided for turning on the first circuit, And a switching element which is turned on by the current flowing in the first circuit and classifies the current flowing in the first circuit.

According to another preferred embodiment of the present invention, the switching element is constituted by a transistor whose base is connected to the first circuit and emitters and collectors are connected to both ends of the second winding portion, respectively do.

The leakage detecting circuit of the earth leakage breaker according to the present invention includes the first circuit for transmitting the output signal of the video current transformer and the second circuit for categorizing and flowing the current of the first circuit so that even when the ground fault current is detected, It is possible to provide an effect of detecting the current by reducing the area.

The electrical leak detecting circuit of the earth leakage breaker according to the present invention further includes an operational amplifier circuit section for operational amplifying a detection signal transmitted by the first circuit and a leakage judging circuit section, It is possible to obtain an effect of determining whether a short circuit is generated or not.

Since the electrical leak detecting circuit of the earth leakage breaker according to the present invention further includes a resistor connected in parallel to both ends of the first winding section, it is possible to provide an effect that the detection signal can be provided as a voltage signal by the voltage across the resistor have.

Since the electric leakage detecting circuit of the earth leakage breaker according to the present invention further includes a switching element which is turned on by the current flowing in the first circuit when a ground fault current is generated, the current flowing through the first circuit when the ground fault current is generated is reduced, The occurrence of the saturation phenomenon of the current transformer is prevented so that the ground fault current can be detected even when the ground fault occurs.

In the electrical leak detecting circuit for an earth leakage breaker according to the present invention, since the switching element is composed of a transistor, it is possible to provide an effect that a second circuit that operates when a ground fault occurs can be provided by connecting a simple and inexpensive transistor.

1 is a block diagram showing a configuration of an electrical leak detecting circuit of a ground fault circuit breaker according to a related art,
FIG. 2 is a waveform diagram of a leakage current when a leakage current is generated within an allowable range in the leakage detection circuit of the leakage circuit breaker according to the prior art,
3 is a waveform diagram of a leakage current (ground fault current) when a leakage current exceeding the allowable range is generated in the leakage detection circuit of the leakage circuit breaker according to the prior art,
4 is a block diagram showing a configuration of an electric leakage detection circuit of an earth leakage breaker according to a preferred embodiment of the present invention,
5 is a block diagram showing a detailed configuration of a detection circuit part in an electrical leak detecting circuit of an earth leakage breaker according to a preferred embodiment of the present invention,
FIG. 6 is a waveform diagram of a leakage current (ground fault current) when a leakage current exceeding an allowable range is generated in the leakage detection circuit of the leakage circuit breaker according to the prior art.

The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.

FIG. 4 is a block diagram showing a configuration of an electrical leak detecting circuit of an electrical leakage circuit breaker according to a preferred embodiment of the present invention, FIG. 5 is a block diagram showing a detailed configuration of a detecting circuit part of an electrical leak detecting circuit of an electrical leakage circuit breaker according to a preferred embodiment of the present invention Fig. 6 is a waveform diagram of a leakage current (ground fault current) when a leakage current exceeding an allowable range in the leakage detection circuit of the leakage circuit breaker according to the related art is generated.

4, the electrical leak detecting circuit of the earth leakage breaker according to the preferred embodiment of the present invention is configured to include the video current transformer 1, the first circuit 5, and the second circuit 6. [

The video current transformer 1 detects a ground fault current and outputs a detection signal. Specifically, in the case where the three-phase circuit of the earth leakage breaker is installed so as to pass through the inside of the ring-shaped core, the image current transformer 1 generates the induction current Is detected by a winding wound around the core.

The first circuit 5 has a first winding part 5a wound on one side of the video current transformer 1 and receives the detection signal from the first winding part 5a and delivers it.

The second circuit (6) has a second winding portion (6a) wound on the other side of the video current transformer (1).

The second circuit 6 is connected to the first circuit 5 and divides the current flowing in the first circuit 5 when the ground fault current is generated and flows it. That is, the current flowing in the first circuit (5) is divided into the second circuit (6) when the ground fault current is generated.

The electrical leak detecting circuit of the earth leakage breaker according to the preferred embodiment of the present invention may further include a detecting circuit unit 3 for detecting electrical leakage based on the detection signal, And may include an operational amplifier circuit portion 3a and a leakage judgment circuit portion 3b, as will be described below.

The operational amplifier circuit unit 3a is connected to the first circuit 5 and operatively amplifies the detection signal transmitted by the first circuit 5. [

The leakage judging circuit portion 3b is connected to the operational amplifying circuit portion 3a and compares the operational amplified detection signal with a predetermined leakage judging reference value to determine whether or not a leakage current has occurred.

The electrical leak detecting circuit of the earth leakage breaker according to the preferred embodiment of the present invention may further include a resistor 2 connected in parallel to both ends of the first winding 5a to provide a detection signal as a voltage signal.

The leakage detecting circuit of the earth leakage breaker according to the preferred embodiment of the present invention is configured such that a trigger terminal for TURN ON is connected to the first circuit 5, And further includes a switching element 4 which is turned on by the current to classify (reduce) the current flowing in the first circuit 5.

According to a preferred embodiment, the switching element 4 has a base BASE connected to the first circuit 5 and an emitter and a collector at both ends of the second winding portion 6a Respectively.

The operation of the electrical leak detecting circuit of the earth leakage breaker according to the preferred embodiment of the present invention constructed as described above will be described with reference to Figs. 4 to 6. Fig.

When an allowable level of leakage current flows on the circuit, the current flowing through the first circuit 5 induced in the first winding portion 5a of the video current transformer 1 is minute, The switching element 4 is not turned on so that the switching element 4 is turned off.

The microcurrent flowing through the first circuit (5) is provided to the detection circuit section (3) as a voltage signal formed across the resistor (2).

Then, the operational amplifier circuit section 3a of the detection circuit section 3 computes and amplifies the detection signal transmitted by the first circuit 5 and provides it to the electrical leak judgment circuit section 3b.

At this time, the pulse waveform of the operational amplified detection signal provided by the operational amplifier circuit 3a can be referred to the waveform shown in FIG.

The leakage judging circuit 3b compares the operational amplified detection signal with a predetermined leakage judging reference value to determine whether or not a leak has occurred.

On the other hand, the operation of the electrical leak detecting circuit of the earth leakage breaker according to the preferred embodiment of the present invention will be described when a leakage current exceeding an allowable level, for example, a ground fault current flows on the circuit.

When a leakage current exceeding an allowable level, for example, a ground fault current flows on the circuit, the current flowing through the first circuit 5 induced in the first winding portion 5a of the video current transformer 1 becomes large.

Therefore, the voltage formed in the resistor 2 is also at a level enough to turn on the switching device 4, so that the switching device 4 is turned on and thus the second circuit 6 is formed.

Thus, the large current flowing through the first circuit 5 is divided and flows through the second circuit 6, so that the current flowing through the first circuit 5 is reduced.

At this time, a current flowing through the reduced first circuit 5 is provided to the detection circuit unit 3 as a voltage signal formed at both ends of the resistor 2.

Then, the operational amplifier circuit section 3a of the detection circuit section 3 computes and amplifies the detection signal transmitted by the first circuit 5 and provides it to the electrical leak judgment circuit section 3b.

At this time, the pulse waveform of the operational amplified detection signal provided by the operational amplifier circuit section 3a has a pulse width sufficient for the leakage determination circuit section 3b at the subsequent stage to process as shown in the waveform of FIG.

Thereafter, the leakage judging circuit 3b compares the operational amplified detection signal with a predetermined leakage judging reference value to determine whether or not a leak has occurred.

Since the detection signal exceeds a predetermined leakage judgment reference value when a ground fault occurs, the leakage judgment circuit section 3b determines occurrence of a leakage current.

As described above, since the electrical leak detecting circuit of the earth leakage breaker according to the present invention includes the first circuit for transmitting the output signal of the video current transformer and the second circuit for classifying and flowing the current of the first circuit, It is possible to reduce the saturation region of the video current transformer and to provide an effect of detecting the current.

1: Video transformer 2: Resistance
3: detection circuit unit 3a: operational amplifier circuit unit
3b: Leakage judgment circuit part 4: Switching element
5: first circuit 5a: first winding section
6: second circuit 6a: second winding section

Claims (5)

In an electrical leak detecting circuit for an earth leakage breaker,
A video current transformer for detecting a ground fault current and outputting a detection signal;
A detection circuit unit for detecting a short circuit based on the detection signal;
A first circuit having a first winding part wound on one side of the video current transformer and transmitting the detection signal received from the first winding part to the detection circuit part; And
And a second circuit having a second winding part wound on the other side of the image current transformer and connected to the first circuit to classify and flow the current of the first circuit when a ground fault current is generated. The method according to claim 1,
The detection circuit section
An operational amplifier circuit connected to the first circuit for operational amplifying the detection signal transmitted by the first circuit; And
And an electrical leak detecting circuit connected to the operational amplifier circuit for comparing the operational amplified detection signal with a predetermined electrical leak judgment reference value to determine whether or not a electrical leak has occurred. The method according to claim 1,
And a resistor connected in parallel to both ends of the first winding section to provide a detection signal as a voltage signal. The method according to claim 1,
And a switching element connected to a first circuit for turning on a transistor for turning on and for turning on the current flowing in the first circuit and classifying the current flowing in the first circuit when a ground fault current is generated Leakage current detection circuit of the earth leakage breaker. 5. The method of claim 4,
Wherein the switching element is composed of a transistor whose base is connected to the first circuit and whose emitters and collectors are connected to both ends of the second winding part, .
KR1020160034184A 2016-03-22 2016-03-22 Electric leakage detecting circuit for electric leakage circuit breaker KR20170109939A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
KR1020160034184A KR20170109939A (en) 2016-03-22 2016-03-22 Electric leakage detecting circuit for electric leakage circuit breaker

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
KR1020160034184A KR20170109939A (en) 2016-03-22 2016-03-22 Electric leakage detecting circuit for electric leakage circuit breaker

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KR20170109939A true KR20170109939A (en) 2017-10-10

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR102039272B1 (en) * 2018-08-23 2019-10-31 주식회사 에프램 A DC Power Current Detection Circuit
KR102039268B1 (en) * 2018-08-23 2019-10-31 주식회사 에프램 An Alternating and Direct Current Detection Circuit
CN111308398A (en) * 2020-03-31 2020-06-19 深圳供电局有限公司 Method and device for judging polarity of zero sequence current transformer in transformer substation

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR102039272B1 (en) * 2018-08-23 2019-10-31 주식회사 에프램 A DC Power Current Detection Circuit
KR102039268B1 (en) * 2018-08-23 2019-10-31 주식회사 에프램 An Alternating and Direct Current Detection Circuit
CN111308398A (en) * 2020-03-31 2020-06-19 深圳供电局有限公司 Method and device for judging polarity of zero sequence current transformer in transformer substation

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