WO2009002120A2 - Measuring instrument for a resistive electric leakage current - Google Patents
Measuring instrument for a resistive electric leakage current Download PDFInfo
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- WO2009002120A2 WO2009002120A2 PCT/KR2008/003729 KR2008003729W WO2009002120A2 WO 2009002120 A2 WO2009002120 A2 WO 2009002120A2 KR 2008003729 W KR2008003729 W KR 2008003729W WO 2009002120 A2 WO2009002120 A2 WO 2009002120A2
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- leakage current
- voltage
- synchronization signal
- signal generator
- under test
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Classifications
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- 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
- G01R31/50—Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections
- G01R31/52—Testing for short-circuits, leakage current or ground faults
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R27/00—Arrangements for measuring resistance, reactance, impedance, or electric characteristics derived therefrom
- G01R27/02—Measuring real or complex resistance, reactance, impedance, or other two-pole characteristics derived therefrom, e.g. time constant
- G01R27/16—Measuring impedance of element or network through which a current is passing from another source, e.g. cable, power line
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R27/00—Arrangements for measuring resistance, reactance, impedance, or electric characteristics derived therefrom
- G01R27/02—Measuring real or complex resistance, reactance, impedance, or other two-pole characteristics derived therefrom, e.g. time constant
- G01R27/16—Measuring impedance of element or network through which a current is passing from another source, e.g. cable, power line
- G01R27/18—Measuring resistance to earth, i.e. line to ground
Definitions
- the present invention relates, in general, to an instrument for measuring ground-resistive leakage current, and, more particularly, to an instrument for measuring leakage current, which can rapidly and accurately measure ground-resistive leakage current using a simple circuit construction.
- leakage current is generally measured using a zero current transformer in the prior art
- the leakage current measured using the zero current transformer, is a composite leakage current in which ground-resistive leakage current is added to ground capacitive leakage current attributable to the ground electric capacity of a line under test, so that the actual leakage state of an AC line, that is, the quantity of the ground-resistive leakage current of a line under test, cannot be known.
- FIG. 1 shows an example of a prior art instrument 30 for measuring ground-resistive leakage current capable of measuring only the ground- resistive leakage current of a line under test.
- the prior art instrument 30 for measuring ground-resistive leakage current includes a leakage current detection circuit 31 for detecting composite leakage current from a line 20 under test; a current-to-voltage conversion circuit 32 for converting the composite leakage current from the leakage current detection circuit 31 into voltage corresponding to the composite leakage current; an amplifier 33 for amplifying an output signal from the current-to-voltage conversion circuit 32; a synchronization signal generator 34 for detecting voltage from the line 20 under test and then generating a synchronization signal; a synchronous detector 35 for receiving the synchronization signal from the synchronization signal generator 34, synchronously detecting the output signal from the amplifier, and then outputting the detected output signal; and a smoothing circuit 36 for smoothing the output signal from the synchronous detector 35, and then outputting ground-resistive leakage current.
- the composite leakage current, detected by the leakage current detection circuit 31, is converted into voltage corresponding to the composite leakage current by the current-to-voltage conversion circuit 32, the resulting voltage is amplified to a value which is appropriate for the measurement using the amplifier, and then the amplified voltage is input to the synchronous detector 35.
- the synchronous detector 35 synchronously detects the output signal from the amplifier 35 using the synchronization signal from the synchronization signal generator 34, and the smoothing circuit 36 smoothes the output signal from the synchronous detector 35.
- the value of a signal, which is synchronously detected by the synchronous detector 35 and then smoothed by the smoothing circuit 36, is ground-resistive leakage current.
- a Resistor-Capacitor (RC) filter is generally used as the smoothing circuit, and it is preferable that the time constant of the RC filter be sufficiently large in order to smooth output.
- an object of the present invention is to provide an instrument for measuring ground-resistive leakage current which can accurately and rapidly measure varying ground-resistive leakage current using only simple circuit configuration.
- the present invention provides an instrument for measuring ground-resistive leakage current, comprising a leakage current detection circuit for detecting composite leakage current from a line under test; a current-to-voltage conversion circuit for converting the composite leakage current from the leakage current detection circuit into corresponding voltage, and then outputting the resulting voltage; an amplifier for amplifying an output signal from the current-to- voltage conversion circuit; a phase inverter for inverting the phase of one of output signals from the amplifier by an angle of 180° ; a synchronization signal generator for detecting voltage from the line under test and then generating synchronization signals; a first half-wave integrator for receiving one of the synchronization signals from the synchronization signal generator, and integrating one of the output signal from the amplifier for each half period; a second half-wave integrator for receiving a remaining synchronization signal from the synchronization signal generator, and integrating an output signal from the phase inverter for each half period; and a sample/hold circuit for
- the present invention provides a method of measuring the ground-resistive leakage current Ir of a line 20 under test for each half period of a power source 10 in detail using a leakage current detection circuit 41, a current-to-voltage conversion circuit 42, an amplifier 43, a phase inverter 44, a synchronization signal generator 45, two half-wave integrators 46 and 47 and a sample/hold circuit 48, with the result that the varying ground-resistive leakage current Ir of the line 20 under test is accurately and rapidly measured, so that there is an advantage in that rapid management can be performed when abnormality occurs in the line 20 under test.
- FIG. 1 is a view showing a prior art instrument for measuring ground- resistive leakage current
- FIG. 2 is a view showing an instrument for measuring leakage current according to the present invention
- FIG. 3 is a vector diagram showing the phase relationship between composite leakage current, ground-resistive leakage current, and ground capacitive leakage current.
- FIG. 4 is a view showing the operation of the instrument for measuring leakage current according to the present invention.
- FIG. 2 is a view showing an instrument for measuring leakage current according to the present invention, the same reference numerals are used throughout the drawing to designate the same components of FIG. 1 which shows the prior art, and a description thereof will be omitted.
- the instrument 40 for measuring ground-resistive leakage current includes a leakage current detection circuit 41 for detecting composite leakage current from a line 20 under test; a current-to-voltage conversion circuit 42 for converting the composite leakage current from the leakage current detection circuit 41 into corresponding voltage, and then outputting the resulting voltage; an amplifier 43 for amplifying an output signal from the current-to-voltage conversion circuit 42; a phase inverter 44 for inverting the phase of one of output signals from the amplifier 43 by an angle of 180° ; a synchronization signal generator 45 for detecting voltage from the line 20 under test and then generating synchronization signals; a first half-wave integrator 46 for receiving one of the synchronization signals from the synchronization signal generator 45, and integrating one of the output signal from the amplifier 43 for each half period; a second half- wave integrator 47 for receiving a remaining synchronization signal from the synchronization signal generator 45, and integrating an output signal from the phase inverter 44 for each half
- a well-known zero current transformer for detecting composite leakage current while surrounding the line 20 under test is applied as the leakage current detection circuit 41.
- a well-known resistor R is applied as the current-to-voltage conversion circuit 42.
- a well-known pulse signal generator which is connected to the line 20 under test and configured to perform division on the voltage of the line and then measure the resulting voltage, and to generate a pulse (a (zero cross pulse) whenever the polarity of the voltage is changed, is applied as the synchronization signal generator 45.
- a ground-resistive leakage current effective value Ir has the same phase as the voltage effective value V of the line 20 under test
- the ground capacitive leakage current effective value Ic has a phase which precedes the phase of the voltage effective value V of the line 20 under test by an angle of 90°
- the composite leakage current effective value Ig is the vector addition of the effective value Ir of the ground- resistive leakage current and the effective value Ic of the ground capacitive leakage current, and it can be seen that the composite leakage current effective value Ig has a phase which precedes the phase of the voltage effective value V of the line 20 under test by an angle of ⁇ .
- Equation 1 Equation 1 (refer to (a) of Fig. 4):
- V is the voltage effective value of the line 20 under test
- w 2 ⁇ f, where f is the power frequency of the line 20 under test.
- Ig is the effective value of composite leakage current
- ⁇ is a phase angle made by the voltage instantaneous value v of the line 20 under test and the instantaneous value ig of the composite leakage current.
- K is the gain of the amplifier 22
- N is the current transformation ratio of the leakage current detection circuit 41
- R is the resistance of the current-to-voltage conversion circuit 42 connected to the secondary side of the leakage current detection circuit 41.
- the first half-wave integrator 46 and the second half-wave integrator 47 respectively receive the synchronization signals Sl and S2 of the synchronization signal generator 45 (refer to (b) of FIG. 4), and then alternately integrate the output signal vl of the amplifier 43 and the output signal v2 of the phase inverter 44 for each half period of the power source 10.
- Equation 5 The integrated output Pl of the first half-wave integrator 46 can be expressed using the following Equation 5:
- Equation 6 Equation 6
- both the integrated output Pl of the first half-wave integrator 46 and the integrated output P2 of the second half-wave integrator 47 become the ground-resistive leakage current Ir.
- the ground-resistive leakage current Ir is measured for each half period of the power source 10, so that the occurrence of abnormality in the line 20 under test can be accurately and rapidly detected (by measuring the ground-resistive leakage current for each half period of the power), compared to the prior art instrument 30 for measuring ground-resistive leakage current.
- the sample/hold circuit 48 receives the synchronization signals Sl and S2 from the synchronization signal generator 45, alternately performs sampling on the integrated output Pl of the first half-wave integrator 46 and the integrated output P2 of the second half-wave integrator 47, and then holds each of the integrated outputs during a half period (refer to (e) of FIG.4).
- the output signal Y of the sample/hold circuit 47 has a complete direct current waveform when the ground-resistive leakage current Ir is constant, but the waveform of the output signal Y of the sample/hold circuit 47 is changed into a staircase waveform when the ground-resistive leakage current Ir varies.
- the applied first and second half-wave integrators 46 and 47 and sample/hold circuit 48 are embodied in an analog manner, they can be embodied in a digital manner if necessary.
- the instrument 40 for measuring ground-resistive leakage current when abnormality occurs in the line 20 under test, the instrument 40 for measuring ground-resistive leakage current according to the present invention can rapidly detect the abnormality. Therefore, it is preferable that the instrument 40 for measuring ground-resistive leakage current be applied to an electric leakage breaker so that the electric leakage breaker can rapidly cut off the line 20 under test when leakage current occurs.
- the present invention is not limited thereto, and can be applied to and utilized in various fields.
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- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Testing Of Short-Circuits, Discontinuities, Leakage, Or Incorrect Line Connections (AREA)
- Emergency Protection Circuit Devices (AREA)
Abstract
An instrument for measuring ground-resistive leakage current is disclosed. A leakage current detection circuit detects composite leakage current from a line under test. A current-to-voltage conversion circuit converts the composite leakage current from the leakage current detection circuit into corresponding voltage, and then outputs the resulting voltage. An amplifier amplifies an output signal from the current-to-voltage conversion circuit. A phase inverter inverts the phase of one of output signals from the amplifier. A synchronization signal generator detects voltage from the line under test and then generates synchronization signals. Two half-wave integrators receive the synchronization signals from the synchronization signal generator and alternately integrate the output signals from the amplifier for each half period. A sample/hold circuit receives the synchronization signals from the synchronization signal generator, alternately performs sampling on outputs from the half-wave integrators for each half period and then holds values corresponding to the outputs for a half period.
Description
[DESCRIPTION] [Invention Title]
MEASURING INSTRUMENT FOR A RESISTIVE ELECTRIC LEAKAGE CURRENT [Technical Field]
<i> The present invention relates, in general, to an instrument for measuring ground-resistive leakage current, and, more particularly, to an instrument for measuring leakage current, which can rapidly and accurately measure ground-resistive leakage current using a simple circuit construction.
<2>
[Background Art]
<3> As well known, if the ground insulation resistance of an Alternating Current (AC) line or the ground insulation resistance of an electric device connected to the corresponding AC line is degraded, ground-resistive leakage current increases, so that electric fires or electric shock accidents may occur.
<4> Therefore, in order to prevent the accidents from occurring, the ground-resistive leakage current should be accurately measured, so that electric fires or electric shock accidents attributable to leakage current can be prevented.
<5> Although leakage current is generally measured using a zero current transformer in the prior art, the leakage current, measured using the zero current transformer, is a composite leakage current in which ground-resistive leakage current is added to ground capacitive leakage current attributable to the ground electric capacity of a line under test, so that the actual leakage state of an AC line, that is, the quantity of the ground-resistive leakage current of a line under test, cannot be known.
<6> In order to solve the above-described problem, research in methods of measuring only the ground-resistive leakage current of a line under test has been actively conducted, and some of the methods are already known and commercially applied.
<7> FIG. 1 shows an example of a prior art instrument 30 for measuring
ground-resistive leakage current capable of measuring only the ground- resistive leakage current of a line under test.
<8> Referring to the drawing, the prior art instrument 30 for measuring ground-resistive leakage current includes a leakage current detection circuit 31 for detecting composite leakage current from a line 20 under test; a current-to-voltage conversion circuit 32 for converting the composite leakage current from the leakage current detection circuit 31 into voltage corresponding to the composite leakage current; an amplifier 33 for amplifying an output signal from the current-to-voltage conversion circuit 32; a synchronization signal generator 34 for detecting voltage from the line 20 under test and then generating a synchronization signal; a synchronous detector 35 for receiving the synchronization signal from the synchronization signal generator 34, synchronously detecting the output signal from the amplifier, and then outputting the detected output signal; and a smoothing circuit 36 for smoothing the output signal from the synchronous detector 35, and then outputting ground-resistive leakage current.
<9> The operation of the prior art instrument 30 for measuring ground- resistive leakage current will be described below.
<io> First, the composite leakage current, detected by the leakage current detection circuit 31, is converted into voltage corresponding to the composite leakage current by the current-to-voltage conversion circuit 32, the resulting voltage is amplified to a value which is appropriate for the measurement using the amplifier, and then the amplified voltage is input to the synchronous detector 35.
<π> The synchronous detector 35 synchronously detects the output signal from the amplifier 35 using the synchronization signal from the synchronization signal generator 34, and the smoothing circuit 36 smoothes the output signal from the synchronous detector 35. The value of a signal, which is synchronously detected by the synchronous detector 35 and then smoothed by the smoothing circuit 36, is ground-resistive leakage current.
<12> Here, a Resistor-Capacitor (RC) filter is generally used as the
smoothing circuit, and it is preferable that the time constant of the RC filter be sufficiently large in order to smooth output.
<13> However, since the prior art instrument 30 for measuring ground- resistive leakage current uses an RC filter having a large time constant, a time required for the output of the smoothing circuit 36 is increased when the insulation of the line 20 under test is suddenly damaged or leakage current is suddenly increased due to the occurrence of an electric shock, so that a problem occurs in that rapid management cannot be performed when abnormality occurs in the line 20 under test.
<14>
[Disclosure]
[Technical Problem]
<i5> Accordingly, the present invention has been made keeping in mind the above problem occurring in the prior art, and an object of the present invention is to provide an instrument for measuring ground-resistive leakage current which can accurately and rapidly measure varying ground-resistive leakage current using only simple circuit configuration.
[Technical Solution]
<16> In order to accomplish the above object, the present invention provides an instrument for measuring ground-resistive leakage current, comprising a leakage current detection circuit for detecting composite leakage current from a line under test; a current-to-voltage conversion circuit for converting the composite leakage current from the leakage current detection circuit into corresponding voltage, and then outputting the resulting voltage; an amplifier for amplifying an output signal from the current-to- voltage conversion circuit; a phase inverter for inverting the phase of one of output signals from the amplifier by an angle of 180° ; a synchronization signal generator for detecting voltage from the line under test and then generating synchronization signals; a first half-wave integrator for receiving one of the synchronization signals from the synchronization signal generator, and integrating one of the output signal from the amplifier for
each half period; a second half-wave integrator for receiving a remaining synchronization signal from the synchronization signal generator, and integrating an output signal from the phase inverter for each half period; and a sample/hold circuit for receiving the synchronization signals from the synchronization signal generator, alternately sampling outputs from the first and second half-wave integrators for each half period and then holding values corresponding to the outputs for a half period.
<17>
[Advantageous Effects]
<i8> According to the above-described present invention, the present invention provides a method of measuring the ground-resistive leakage current Ir of a line 20 under test for each half period of a power source 10 in detail using a leakage current detection circuit 41, a current-to-voltage conversion circuit 42, an amplifier 43, a phase inverter 44, a synchronization signal generator 45, two half-wave integrators 46 and 47 and a sample/hold circuit 48, with the result that the varying ground-resistive leakage current Ir of the line 20 under test is accurately and rapidly measured, so that there is an advantage in that rapid management can be performed when abnormality occurs in the line 20 under test.
<19>
[Description of Drawings]
<20> FIG. 1 is a view showing a prior art instrument for measuring ground- resistive leakage current;
<2i> FIG. 2 is a view showing an instrument for measuring leakage current according to the present invention;
<22> FIG. 3 is a vector diagram showing the phase relationship between composite leakage current, ground-resistive leakage current, and ground capacitive leakage current; and
<23> FIG. 4 is a view showing the operation of the instrument for measuring leakage current according to the present invention.
<24> - Description of reference numerals of principal elements in the
drawings -
<25> 10; power source 20; line under test
<26> 40; instrument for measuring leakage current
<27> 41; leakage current detection circuit
<28> 42; current-to-voltage conversion circuit 43; amplifier
<29> 44; phase inverter
<30> 45; synchronization signal generator
<3i> 46; first half-wave integrator
<32> 47; second haIf-wave integrator,
<33> 48; sample/hold circuit
<34>
[Mode for Invention]
<35> Hereinafter, the present invention will be described in detail with reference to the attached drawings.
<36> FIG. 2 is a view showing an instrument for measuring leakage current according to the present invention, the same reference numerals are used throughout the drawing to designate the same components of FIG. 1 which shows the prior art, and a description thereof will be omitted.
<37> Referring to FIG. 2, the instrument 40 for measuring ground-resistive leakage current includes a leakage current detection circuit 41 for detecting composite leakage current from a line 20 under test; a current-to-voltage conversion circuit 42 for converting the composite leakage current from the leakage current detection circuit 41 into corresponding voltage, and then outputting the resulting voltage; an amplifier 43 for amplifying an output signal from the current-to-voltage conversion circuit 42; a phase inverter 44 for inverting the phase of one of output signals from the amplifier 43 by an angle of 180° ; a synchronization signal generator 45 for detecting voltage from the line 20 under test and then generating synchronization signals; a first half-wave integrator 46 for receiving one of the synchronization signals from the synchronization signal generator 45, and integrating one of the output signal from the amplifier 43 for each half period; a second half-
wave integrator 47 for receiving a remaining synchronization signal from the synchronization signal generator 45, and integrating an output signal from the phase inverter 44 for each half period; and a sample/hold circuit 48 for receiving the synchronization signals from the synchronization signal generator 45, alternately sampling outputs from the first and second half- wave integrators 46 and 47 for each half period and then holding values corresponding to the outputs for a half period.
<38> A well-known zero current transformer for detecting composite leakage current while surrounding the line 20 under test is applied as the leakage current detection circuit 41.
<39> A well-known resistor R is applied as the current-to-voltage conversion circuit 42.
<40> Since the amplifier 43 and the phase inverter 44 have already been widely well known in the related art and commercially applied, a description thereof will be omitted.
<4i> A well-known pulse signal generator, which is connected to the line 20 under test and configured to perform division on the voltage of the line and then measure the resulting voltage, and to generate a pulse (a (zero cross pulse) whenever the polarity of the voltage is changed, is applied as the synchronization signal generator 45.
<42> Well-known operators OP Amps are applied as the first half-wave integrator 46 and the second half-wave integrator 47, the first and second half-wave integrators 46 and 47 receive synchronization signals from the synchronization signal generator 45, respectively, and then alternately integrate the output signals from the amplifier 43 and the phase inverter 44 for each half period (the half period of the power source 10).
<43> Since the sample/hold circuit 48 has already been widely well known in the related art and used in public, a detailed description thereof will be omitted.
<44> With reference to FIGS. 3 and 4, an operation of the instrument 40 for measuring ground-resistive leakage current according to the present invention
will be described below.
<45> As shown in FIG. 3, a ground-resistive leakage current effective value Ir has the same phase as the voltage effective value V of the line 20 under test, the ground capacitive leakage current effective value Ic has a phase which precedes the phase of the voltage effective value V of the line 20 under test by an angle of 90° , and the composite leakage current effective value Ig is the vector addition of the effective value Ir of the ground- resistive leakage current and the effective value Ic of the ground capacitive leakage current, and it can be seen that the composite leakage current effective value Ig has a phase which precedes the phase of the voltage effective value V of the line 20 under test by an angle of θ.
<46> If the power source 10 of the line 20 under test has a sine wave which includes no harmonic wave, the voltage instantaneous value v of the line 20 under test is obtained using the following Equation 1 (refer to (a) of Fig. 4):
<47> [Equiation 1]
<48> v=FX V 2 sinO0
<49> where, V is the voltage effective value of the line 20 under test, and w=2πf, where f is the power frequency of the line 20 under test.
<50> Meanwhile, if the composite leakage current of the line 20 under test has a sine wave which includes no harmonic wave, the composite leakage current instantaneous value ig of the line 20 under test, the output signal vl of the amplifier 43, and the output signal v2 of the phase inverter 44 are respectively obtained using the following Equation 2, Equation 3, and Equation 4 (refer to (c) of Fig.4):
<5i> [Equation 2]
<52> ig=Igx V 2sin(wr+θ)
<53> where, Ig is the effective value of composite leakage current, θ is a phase angle made by the voltage instantaneous value v of the line 20 under test and the instantaneous value ig of the composite leakage current.
<54> [Equat ion 3]
<55> vl =KXNXR X ig-KXNXR XIgX \r2 sin(wt+Q)
<56> where, K is the gain of the amplifier 22, N is the current transformation ratio of the leakage current detection circuit 41, and R is the resistance of the current-to-voltage conversion circuit 42 connected to the secondary side of the leakage current detection circuit 41.
<57> [Equation 4]
<58> v2=-vl --KXNXR XIgX V 2 sin(w/+θ)
<59> The first half-wave integrator 46 and the second half-wave integrator 47 respectively receive the synchronization signals Sl and S2 of the synchronization signal generator 45 (refer to (b) of FIG. 4), and then alternately integrate the output signal vl of the amplifier 43 and the output signal v2 of the phase inverter 44 for each half period of the power source 10.
<60> Here, based on Equation 3 and Equation 4, the phase of the output signal vl of the amplifier 43 and the phase of the output signal v2 of the phase inverter 44 are opposite to each other, and integrated outputs Pl and P2, which are alternately output from the first half-wave integrator 46 and the second half-wave integrator 47, are obtained, as shown in (d) of FIG.4.
<6i> The integrated output Pl of the first half-wave integrator 46 can be expressed using the following Equation 5:
<62> [Equation 5]
Pl =Kl X vld(wt)=Kl XKXNXR XIgX 2y/2cosQ
<63>
<64> where Kl is the gain of the first half-wave integrator 45. <65> Further, the integrated output P2 of the second half-wave integrator 47 can be expressed using the following Equation 6:
<66> [Equat ion 6] XKXNXR XIgX
<68> where K2 is the gain of the second half-wave integrator 47, and Kl = K2.
<69> Therefore , i f Equat ion
. g real i zed by adjust ing the gain Kl of the f irst hal f-wave integrator 46 and the gain K2 of the second hal f-wave integrator 47, the integrated outputs Pl and P2 of the respect ive f irst and second hal f-wave integrators 46 and 47 are obtained using the fol lowing Equat ion 7 : <70> [Equat ion 7]
<71> Pl =P2=IgX cosθ-Ir
<72> That is, both the integrated output Pl of the first half-wave integrator 46 and the integrated output P2 of the second half-wave integrator 47 become the ground-resistive leakage current Ir.
<73> In the case of the instrument 40 for measuring ground-resistive leakage current according to the present invention, the ground-resistive leakage current Ir is measured for each half period of the power source 10, so that the occurrence of abnormality in the line 20 under test can be accurately and rapidly detected (by measuring the ground-resistive leakage current for each half period of the power), compared to the prior art instrument 30 for measuring ground-resistive leakage current.
<74> The sample/hold circuit 48 receives the synchronization signals Sl and S2 from the synchronization signal generator 45, alternately performs sampling on the integrated output Pl of the first half-wave integrator 46 and the integrated output P2 of the second half-wave integrator 47, and then holds each of the integrated outputs during a half period (refer to (e) of FIG.4).
<75> Therefore, the output signal Y of the sample/hold circuit 47 has a complete direct current waveform when the ground-resistive leakage current Ir is constant, but the waveform of the output signal Y of the sample/hold circuit 47 is changed into a staircase waveform when the ground-resistive leakage current Ir varies.
<76> It is apparent that the present invention is not limited to the above- described embodiment, and various modifications are possible without departing from the gist of the accompanying claims.
<77> For example, although, in the case of the present embodiment, the applied first and second half-wave integrators 46 and 47 and sample/hold circuit 48 are embodied in an analog manner, they can be embodied in a digital manner if necessary.
<78> Further, when abnormality occurs in the line 20 under test, the instrument 40 for measuring ground-resistive leakage current according to the present invention can rapidly detect the abnormality. Therefore, it is preferable that the instrument 40 for measuring ground-resistive leakage current be applied to an electric leakage breaker so that the electric leakage breaker can rapidly cut off the line 20 under test when leakage current occurs. However, the present invention is not limited thereto, and can be applied to and utilized in various fields.
Claims
[CLAIMS] [Claim 1]
An instrument for measuring ground-resistive leakage current, comprising a leakage current detection circuit for detecting composite leakage current from a line under test ; a current-to-voltage conversion circuit for converting the composite leakage current from the leakage current detection circuit into corresponding voltage, and then outputting the resulting voltage! an amplifier for amplifying an output signal from the current-to-voltage conversion circuit ; a phase inverter for inverting a phase of one of output signals from the amplifier by an angle of 180° ; a synchronization signal generator for detecting voltage from the line under test and then generating synchronization signals! a first half-wave integrator for receiving one of the synchronization signals from the synchronization signal generator , and integrating one of the output signal from the amplifier for each half period! a second half-wave integrator for receiving a remaining synchronization signal from the synchronization signal generator , and integrating an output signal from the phase inverter for each half period! and a sample/hold circuit for receiving the synchronization signals from the synchronization signal generator , alternately sampling outputs from the first and second half-wave integrators for each half period and then holding values corresponding to the outputs for a half period.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2008800111454A CN101663589B (en) | 2007-06-28 | 2008-06-27 | Measuring instrument for a resistive electric leakage current |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| KR1020070064664A KR100896091B1 (en) | 2007-06-28 | 2007-06-28 | Earth resistive leakage current measuring instrument |
| KR10-2007-0064664 | 2007-06-28 |
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| Publication Number | Publication Date |
|---|---|
| WO2009002120A2 true WO2009002120A2 (en) | 2008-12-31 |
| WO2009002120A3 WO2009002120A3 (en) | 2009-03-12 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| PCT/KR2008/003729 WO2009002120A2 (en) | 2007-06-28 | 2008-06-27 | Measuring instrument for a resistive electric leakage current |
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|---|---|
| KR (1) | KR100896091B1 (en) |
| CN (1) | CN101663589B (en) |
| WO (1) | WO2009002120A2 (en) |
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| JP5228128B1 (en) * | 2012-05-28 | 2013-07-03 | タナシン電機株式会社 | Signal generation device, measurement device, leakage detection device, and signal generation method |
| US8803569B1 (en) | 2013-06-27 | 2014-08-12 | International Business Machines Corporation | Ramp generator using operational amplifier based integration and switched capacitor techniques |
| JP2016057314A (en) * | 2016-01-12 | 2016-04-21 | パナソニックＩｐマネジメント株式会社 | Leak detection device |
| JP2018128270A (en) * | 2017-02-06 | 2018-08-16 | 株式会社日立産機システム | Insulation monitoring device and insulation monitoring system |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| KR200453295Y1 (en) * | 2009-10-22 | 2011-04-20 | 주식회사 에렐 | Earth Leakage Circuit Breaker for Large Charge Current Converter |
| CA2800584A1 (en) * | 2010-06-07 | 2011-12-15 | Ampcontrol Pty Ltd | Method for detection of leakage or fault currents from equipment in an electrical power system |
| KR101157125B1 (en) * | 2011-05-04 | 2012-06-22 | 주식회사 유컴테크놀러지 | Device for detecting resistive current and method thereof |
| KR101671638B1 (en) * | 2015-07-13 | 2016-11-01 | 김진학 | Apparatus for displaying and warning between ground and electric power lines |
| JP6460146B2 (en) * | 2017-04-21 | 2019-01-30 | オムロン株式会社 | Leakage current calculation device and leakage current calculation method |
| CN110794258B (en) * | 2019-10-28 | 2022-05-06 | 江苏能电科技有限公司 | Electric circuit sparking detection method, device, equipment and storage medium |
| CN111766497B (en) * | 2020-07-28 | 2023-01-17 | 哈尔滨工业大学 | A high-precision weak transient current testing system and method |
| CN112526437A (en) * | 2020-11-27 | 2021-03-19 | 国网湖北省电力有限公司营销服务中心(计量中心) | Real-time acquisition system for running state of high-voltage transformer group |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4558275A (en) * | 1981-04-21 | 1985-12-10 | The Superior Electric Company | Line voltage monitor system |
| US6556397B2 (en) * | 2000-05-12 | 2003-04-29 | Human El-Tech, Inc. | Device and method for detecting arc fault |
| KR200381335Y1 (en) * | 2005-01-18 | 2005-04-12 | 주식회사 텔코코리아 | Electronic earth leakage circuit braker |
| US20060109009A1 (en) * | 2004-11-19 | 2006-05-25 | Esw-Extel Systems Wedel Gesellschaft Fuer Ausruestung Mbh | Method and device for the detection of fault current arcing in electric circuits |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH08182180A (en) | 1994-12-22 | 1996-07-12 | Tempearl Ind Co Ltd | Integration judging circuit and resistance component leakage detecting circuit using it |
| CN2399735Y (en) * | 1999-08-18 | 2000-10-04 | 屠亚奇 | Computer controlled insulation monitor |
| CN2847308Y (en) * | 2005-07-08 | 2006-12-13 | 河海大学常州校区 | Circuit device of leakage current detector of lightning arrestor |
-
2007
- 2007-06-28 KR KR1020070064664A patent/KR100896091B1/en active Active
-
2008
- 2008-06-27 WO PCT/KR2008/003729 patent/WO2009002120A2/en active Application Filing
- 2008-06-27 CN CN2008800111454A patent/CN101663589B/en not_active Expired - Fee Related
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4558275A (en) * | 1981-04-21 | 1985-12-10 | The Superior Electric Company | Line voltage monitor system |
| US6556397B2 (en) * | 2000-05-12 | 2003-04-29 | Human El-Tech, Inc. | Device and method for detecting arc fault |
| US20060109009A1 (en) * | 2004-11-19 | 2006-05-25 | Esw-Extel Systems Wedel Gesellschaft Fuer Ausruestung Mbh | Method and device for the detection of fault current arcing in electric circuits |
| KR200381335Y1 (en) * | 2005-01-18 | 2005-04-12 | 주식회사 텔코코리아 | Electronic earth leakage circuit braker |
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP5228128B1 (en) * | 2012-05-28 | 2013-07-03 | タナシン電機株式会社 | Signal generation device, measurement device, leakage detection device, and signal generation method |
| DE102013008882A1 (en) | 2012-05-28 | 2013-11-28 | Tanashin Denki Co., Ltd. | Signal generation device and signal generation method |
| KR101346498B1 (en) * | 2012-05-28 | 2013-12-31 | 다나신덴기가부시키가이샤 | Signal generation device and signal generation method |
| US9013156B2 (en) | 2012-05-28 | 2015-04-21 | Tanashin Denki Co., Ltd. | Signal generation device and signal generation method |
| DE102013008882B4 (en) * | 2012-05-28 | 2017-04-20 | Tanashin Denki Co., Ltd. | Signal generation device and signal generation method |
| US8803569B1 (en) | 2013-06-27 | 2014-08-12 | International Business Machines Corporation | Ramp generator using operational amplifier based integration and switched capacitor techniques |
| JP2016057314A (en) * | 2016-01-12 | 2016-04-21 | パナソニックＩｐマネジメント株式会社 | Leak detection device |
| JP2018128270A (en) * | 2017-02-06 | 2018-08-16 | 株式会社日立産機システム | Insulation monitoring device and insulation monitoring system |
Also Published As
| Publication number | Publication date |
|---|---|
| KR100896091B1 (en) | 2009-05-14 |
| KR20090000530A (en) | 2009-01-07 |
| WO2009002120A3 (en) | 2009-03-12 |
| CN101663589B (en) | 2012-07-25 |
| CN101663589A (en) | 2010-03-03 |
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