KR101024077B1 - IGR Earth Leakage Current Braker for Fluorescent Lamp - Google Patents

Abstract

The present invention relates to a ground fault circuit breaker, and more particularly, to a ground fault circuit breaker applied to a fluorescent lamp of 5 mA class, a leakage current detector (110) for sensing a composite leakage current (Ig) to a wire connected to a power source; A power synchronization signal generator 120 for generating a power synchronization signal in the form of a pulse signal every half cycle of the AC voltage signal flowing through the wire path; The composite leakage current Ig of the leakage current detector 110 and the power synchronization signal of the power synchronization signal generator 120 are respectively input, and the integrated leakage current Ig is integrally processed during the half cycle of the AC voltage signal to prevent the resistive leakage current Igr. A half-cycle integrator 130 for computing (); A comparator 140 for comparing the resistive leakage current Igr transmitted from the half period integrator 130 with a reference value; Generating and maintaining a high level output according to the signal of the comparator 140, wherein the high level output is maintained only when the electric current is interrupted to the wire; And a relay 160 disposed after one point of the electric wire path in which the holder 150 is energized, and receiving a high level output of the holder 150 to block electric current from the electric wire after the one point. will be.

Description

IGR Earth Leakage Breaker for Fluorescent Lamps {IGR Earth Leakage Current Braker for Fluorescent Lamp}

The present invention relates to an earth leakage breaker, and more particularly, to an IGR earth leakage breaker applied to a 5 mA fluorescent lamp.

A resistive leakage current Igr and a capacitive leakage current Igc flow through the line.

The former is the leakage current flowing to the ground when the earth insulation resistance of the electric wire connected to the electric wire and the electric wire is deteriorated, and the latter is the earth due to the earth capacitance of the electric wire connected to the electric wire and the electric wire. Leakage current flowing in

Electrical disasters such as electric fires or human body electric shocks are caused by the resistive leakage current Igr, and the capacitive leakage current Igc has nothing to do with the electrical disaster. That is, when a large amount of resistance leakage current (Igr) flows, an electric fire occurs and even when a human body is electric shock, resistance leakage current flows mostly. Therefore, in order to prevent an electric disaster, an earth leakage breaker is required to detect a resistive leakage current (Igr) and cut off the electric wire when the current value exceeds a specified value.

The current leakage circuit breaker detects the leakage current rate using the image current transformer (ZCT) and when the current value exceeds the given reference value, the ground fault circuit breaker is operated. When the leakage current rate is detected by using an image current transformer, the synthesized leakage current Ig obtained by combining the resistive leakage current Igr and the capacitive leakage current Igc is detected in the detected leakage current, so that the capacitive leakage current Igc is detected. In large lines, the earth leakage breaker will operate even if the resistive leakage current directly related to the electrical disaster is small. That is, a malfunction occurs.

Recently, fluorescent lamps use electronic ballasts. The electronic ballast is composed of a converter for converting AC power to DC power and an inverter for converting DC power to high frequency. Therefore, a lot of harmonics and high frequency currents flow in the fluorescent wire.

As a result, in a fluorescent light cable line having such a structure, a large amount of harmonics and high frequency capacitive leakage current (Igc) flows not only in the fundamental wave of the power supply but also in the fluorescent light wire through the large capacitance of the cable and the large capacitance of the fluorescent lamp itself. The installation of a high-sensitivity circuit breaker (e.g., 5 mA) of the circuit breaker prevented frequent malfunction of the circuit breaker due to capacitive leakage current (Igc).

Therefore, it has been required to develop an earth leakage breaker that does not cause malfunction due to the capacitive leakage current Igc in a fluorescent lamp line having a large amount of capacitive leakage current Igc.

Therefore, the present invention was invented to solve the above problems, and in the present invention, the capacitive leakage current is removed from the synthetic leakage current detected by the image current transformer, and the resistive leakage current is introduced to operate the resistive leakage current. The purpose is to provide an earth leakage breaker.

According to an aspect of the present invention,

Leakage current detector for detecting a composite leakage current (Ig) to the wire connected to the power source;

A power supply synchronizing signal generator for generating a power synchronizing signal in the form of a pulse signal every half cycle of the AC voltage signal flowing through the cable line;

Half-cycle integrator that calculates resistive leakage current (Igr) by integrating composite leakage current (Ig) during half period of AC voltage signal by receiving the leakage current detector's composite leakage current (Ig) and the power synchronization signal generator's power synchronization signal. ;

A comparator for comparing the resistive leakage current Igr transmitted from the half period integrator with a reference value;

A high level output is generated and maintained according to a signal of a comparator, wherein the high level output is maintained only when the current is interrupted to the wire; And

A relay disposed after one point of the wire path through which the maintainer is energized, and receiving a high level output of the retainer to cut off energization of the wire after the point;

It is a circuit breaker for fluorescent lamps comprising a.

When the IGR earth leakage breaker of the present invention as described above is used, the resistive leakage current from which the capacitive leakage current is removed from the synthetic leakage current detected by the leakage current detector is extracted. Since the circuit breaker is not affected by the capacitive leakage current, the circuit breaker has an effect of greatly reducing the malfunction in the fluorescent lamp line driven by the electronic ballast which generates a large amount of capacitive leakage current.

In addition, since the sensitivity current can be lowered from the current 30 mA to 5 mA level, power loss due to a short circuit can be reduced, and the possibility of electric shock accident can be significantly reduced.

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

1 is a view showing a state of a fluorescent lamp wire with an earth leakage breaker according to the present invention, Figure 2 is a graph showing the phase relationship between the power supply voltage and the leakage current, it will be described with reference to this.

The IGR earth leakage breaker 100 according to the present invention is installed in the first fluorescent lamp 10 of the fluorescent wire and the second fluorescent lamp 20 is installed after the IGR earth leakage breaker 100 at the time of power supply. Therefore, when the IGR earth leakage breaker 100 installed in the first fluorescent lamp 10 is operated, all the fluorescent lamps installed in the corresponding fluorescent wires are cut off from the power source.

In the embodiment according to the present invention, the IGR earth leakage breaker 100 is assumed to be built in the first fluorescent lamp 10, but is not limited to this, of course, the IGR earth leakage breaker 100 may be installed separately.

While the fluorescent lamp is turned on, a synthetic leakage current (Ig) in which the resistive leakage current (Igr) and the capacitive leakage current (Igc), which flow to the ground, flows in the fluorescent wire, and the phase relationship of the leakage current is shown in FIG.

Description number "11", "21" refers to the conventional "electronic ballast" installed in the first, second fluorescent lamps 10, 20, "12", "22" refers to the first, second fluorescent lamps (10, 20, a conventional "fluorescent light bulb" is installed.

3 is a block diagram illustrating an earth leakage breaker according to the present invention.

First, the leakage current to the wire is detected by the leakage current detector 110. At this time, the leakage current detector 110 is composed of a known image current transformer. For reference, the leakage current detected by the image current transformer is the composite leakage current Ig described above.

The power synchronization signal generator 120 is configured to receive an AC voltage signal from a power supply and generate a pulse signal every half cycle of the power supply.

The half-cycle integrator 130 receives the composite leakage current Ig of the leakage current detector 110 and the power synchronization signal of the power synchronization signal generator 120 and integrates the synthesized leakage current Ig during every half cycle of the power supply. Calculate the resistive leakage current (Igr).

The function of the half-cycle integrator 120 is described in detail as follows.

If the synthesized leakage current Ig of the fluorescent wire is a sine wave without harmonics, the instantaneous value i _g may be expressed as shown in Equation 1 below.

Where Ig is the effective value of the composite leakage current, ω is the angular velocity of the power supply voltage, and θ is the phase angle between the cable voltage and the composite leakage current.

The half-cycle integrator 130 integrates the synthesized leakage current Ig for every half cycle of the power supply.

Therefore, the output of the half period integrator 130 may be represented by Equation 2.

Looking at Equation 2 it can be seen that the output of the half-cycle integrator 130 is Igr, that is, a resistive leakage current. In more detail, the half-cycle integrator 130 removes the capacitive leakage current Igc included in the synthetic leakage current Ig and extracts only the resistive leakage current Igr. In the same principle, even if harmonics or high frequencies are included in the capacitive leakage current Igc, the half-cycle integrator 130 is removed.

The comparator 140 includes a known subtraction amplifier and outputs a high level signal when the calculated resistive leakage current Igr exceeds a preset reference value.

The retainer 150 has a high level output when the output of the comparator 140 is a high level signal, and maintains a high level even when the output of the comparator 140 is changed to a low level signal. The retainer 150 is changed to a low level signal only when the power line is turned off. Thus, the retainer 150 will be energized to drive with electricity supplied from the wire path between the branch circuit switch 30 and the relay 160 below.

For reference, the leakage current detector 110, the power synchronization signal generator 120, the half-cycle integrator 130, the comparator 140 and the retainer 150 are supplied with electricity required for driving while energizing the wire. At this time, since the energization point of the retainer 150 takes precedence over the arrangement position of the relay 160 with power as a starting point, the retainer 150 is irrespective of whether the relay 160 is driven and the transmission signal of the comparator 140. High level output is maintained. Of course, when the entire electricity supply to the wire is cut off, since the power supply to the holder 150 is cut off, the high level output of the holder 150 is stopped.

The relay 160 is composed of a known NC contact and a drive coil, and when the output of the retainer 150 is at a high level, the drive coil is excited to open the NC contact. When the NC contact is open, the line is cut off and no leakage current flows. If the leakage current does not flow, the output of the leakage current detector 110 becomes '0' and the output of the comparator 140 becomes a low level, but the output of the retainer 150 remains at a high level and is blocked by the wire. maintain.

The earth leakage indicator 170 is composed of a small lamp or a buzzer and operates when the output of the holder 150 is at a high level to indicate that the wire path is blocked by a short circuit.

If a short circuit occurs and the line is cut off, first, turn off the branch circuit switch 30 and remove the short circuit. When the branch circuit switch 30 is turned on next, since the retainer 150 is changed to the low level, the relay 160 does not operate and the NC contact is closed, so that the first and second fluorescent lamps 10 and 20 light up. . Branch circuit switch 30 also serves to reset the disconnected wire.

The present invention is not limited to the above embodiments, and various modifications can be made without departing from the scope of the following claims.

1 is a view showing a state of a fluorescent lamp wire is installed with a circuit breaker according to the present invention,

2 is a graph showing a phase relationship between a power supply voltage and a leakage current,

3 is a block diagram illustrating an earth leakage breaker according to the present invention.

-Explanation of terms for main parts of attached drawings-

10, 20; First and second fluorescent lamps 100; IGR Earth Leakage Circuit Breaker

110; Leakage current detector 120; Power Synchronization Signal Generator

130; Half-cycle integrator 140; Comparator

150; Maintainer 160; relay

170; Earth leakage indicator

Claims (2)

Leakage current detector 110 for detecting a composite leakage current (Ig) of the wire connected to the power source; A power synchronization signal generator 120 for generating a power synchronization signal in the form of a pulse signal every half cycle of the AC voltage signal flowing through the wire path; The composite leakage current Ig of the leakage current detector 110 and the power synchronization signal of the power synchronization signal generator 120 are respectively input, and the integrated leakage current Ig is integrally processed during the half cycle of the AC voltage signal to prevent the resistive leakage current Igr. A half-cycle integrator 130 for computing (); A comparator 140 for comparing the resistive leakage current Igr transmitted from the half period integrator 130 with a reference value; Generating and maintaining a high level output according to the signal of the comparator 140, wherein the high level output is maintained only when the electric current is interrupted to the wire; A relay 160 disposed after one point of the electric wire path where the power supply is maintained at the time point, and receiving the high level output of the retainer 150 to block electric current from the electric wire after the one point; Eyelight leakage circuit breaker for fluorescent lamp comprising a. The method of claim 1, Receiving the high-level output of the retainer 150, a light leakage indicator 170 for emitting or pronounced operation further comprises a flashlight breaker for fluorescent lamps.

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