WO2008016274A1 - Measuring instrument for an electric current leakage - Google Patents
Measuring instrument for an electric current leakage Download PDFInfo
- Publication number
- WO2008016274A1 WO2008016274A1 PCT/KR2007/003732 KR2007003732W WO2008016274A1 WO 2008016274 A1 WO2008016274 A1 WO 2008016274A1 KR 2007003732 W KR2007003732 W KR 2007003732W WO 2008016274 A1 WO2008016274 A1 WO 2008016274A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- output signal
- conversion circuit
- current
- leakage current
- voltage
- Prior art date
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Classifications
-
- 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
- G01R27/18—Measuring resistance to earth, i.e. line to ground
Definitions
- the present invention relates, in general, to an instrument for measuring leakage current, and, more particularly, to an instrument for measuring leakage current, which can satisfactorily measure ground resistive leakage current using a simple circuit construction.
- leakage current should be accurately measured so that electrical fires or electric shock accidents can be prevented.
- the insulation resistance between a measurement target electric line and ground is measured using a well-known leakage resistance tester in the state in which the supply of power into the measurement target electric line is interrupted.
- a method of measuring the leakage current of a measurement target electric line using a well-known clamp-type current tester in the state in which the supply of power into a measurement target electric line is not interrupted was proposed.
- the value of a leakage current measured using this method is a resultant leakage current, in which a ground resistive leakage current is added to a ground capacitive leakage current. Therefore, in the case in which the ground capacitive leakage current is large, the resultant leakage current is large even when the ground resistive leakage current is small, thereby causing a problem of determining electric leakage, even though electric leakage does not occur.
- Such a leakage current tester employs a method of directly multiplying the instantaneous value of a resultant leakage current, measured from a measurement target electric line, by the instantaneous value of voltage, measured from the measurement target electric line, using a multiplier, and then dividing the resulting value by the effective value of the voltage of the measurement target electric line, thereby detecting ground resistive leakage current.
- an object of the present invention is to provide an instrument for measuring leakage current, which can satisfactorily measure ground resistive leakage current using a simple circuit construction.
- the present invention provides an instrument for measuring a leakage current, including a voltage detection circuit for detecting line voltage from a measurement target electric line; a square wave conversion circuit for converting a sine wave, which is the output signal of the voltage detection circuit, into a square wave; a current detection circuit for detecting resultant leakage current from the measurement target electric line; a current-to-voltage conversion circuit for converting the resultant leakage current of the current detection circuit into voltage corresponding to the resultant leakage current; a polarity conversion circuit for converting the polarity of the output signal of the current-to-voltage conversion circuit and outputting the resulting signal; a selection unit for receiving the output signal of the square wave conversion circuit, the output signal of the current-to-voltage conversion circuit and the output signal of the polarity conversion circuit, and selectively outputting the output signal of the current-to-voltage conversion circuit or the output signals of the polarity conversion circuit according to the polarity of the output signal of the square wave conversion circuit; and a low
- FIG. 1 is a diagram showing an instrument for measuring leakage current according to the present invention
- FIG. 2 is a vector diagram showing the phase relationship between a resultant leakage current, a ground resistive leakage current, and a ground capacitive leakage current;
- FIG. 3 is a view showing the operational state of the instrument for measuring leakage current according to the present invention.
- An instrument for measuring a leakage current includes a voltage detection circuit 2 for detecting line voltage from a measurement target electric line 1, a square wave conversion circuit 3 for converting a sine wave, which is an output signal of the voltage detection circuit 2, into a square wave, a current detection circuit 4 for detecting the resultant leakage current of the measurement target electric line 1, a current-to-voltage conversion circuit 5 for converting the resultant leakage current, output from the current detection circuit 4, into corresponding voltage, a polarity conversion circuit 6 for changing the polarity of the output signal of the current-to- voltage conversion circuit 5 and outputting a resulting signal, a selection unit 7 for receiving an output signal of the square wave conversion circuit 3, an output signal of the current-to-voltage conversion circuit 5, and an output signal of the polarity conversion circuit 6, and selectively outputting the output signal of the current-to-voltage conversion circuit 5 or the output signal of the polarity conversion circuit 6 according to the polarity of the output signal of the square wave conversion circuit
- a well-known voltage detection circuit which is connected to the measurement target electric line 1, divides the line voltage of the measurement target electric line 1 and measures the resulting voltages, is used as the voltage detection circuit 2.
- a well-known current transformer which surrounds the measurement target electric line 1 and detects a resultant leakage current, is used as the current detection circuit 4.
- the square wave conversion circuit 3 Since the square wave conversion circuit 3, the current-to-voltage conversion circuit 5, the polarity conversion circuit 6, the selection unit 7, and the low pass filter 8 are widely known and utilized, detailed descriptions thereof are omitted here.
- the effective value Ir of a ground resistive leakage current has the same phase as the effective value v of a measurement target electric line voltage
- the effective value Ic of a ground capacitive leakage current has a phase advanced by 90° with respect to that of the effective value v of the line voltage
- the effective value *S of a resultant leakage current is the vector sum of the effective .
- the instantaneous value v of the measurement target electric line voltage and the output signal vl of the voltage detection circuit 2 can be expressed by the following Equations 1 and 2.
- the output signal vl is positive (+), that is, if 0 ⁇ ⁇ t ⁇ ⁇ , the output signal v2 of the square wave conversion circuit 3 is -+-- KZ - , If the polarity of the output signal vl is negative (-), that is, if ⁇ ⁇ ⁇ t ⁇ 2 ⁇ , the output signal v2 is ⁇ z .
- the resultant leakage current of the measurement target electric line 1 is a sine wave which does not contain harmonics
- Equations 3, 4, and 5 are expressed by the following Equations 3, 4, and 5.
- ⁇ is the effective value of a resultant leakage current
- ⁇ is the phase angle between the instantaneous value v of the measurement target electric line voltage and the instantaneous value ** of the resultant leakage current.
- K3 is the current ratio of the current detection circuit 4.
- ⁇ 4r is the gain of the current-to-voltage conversion circuit 3.
- the output signal P of the selection unit 7 can be expressed by the following Equation 6 when the polarity of the output signal v2 of the square wave conversion circuit 3 is positive (+), or by the following Equation 7 when the polarity of the output signal v2 of the square wave conversion circuit 3 is negative (-).
- Equation 6 when the polarity of the output signal v2 of the square wave conversion circuit 3 is positive (+)
- Equation 7 when the polarity of the output signal v2 of the square wave conversion circuit 3 is negative (-).
- the output signal s of the low pass filter 8 is a direct current signal corresponding to the average of the output signal P .
- the output signal s of the low pass filter 8 is expressed by the following Equation 8. ) X -J- ( [-cos( ⁇ /+ ⁇ )] 1+ [cos( ⁇ /+ ⁇ )] f )
- the output signal s of the low pass filter 8 is expressed by the following Equation 9.
- FIG. 3(a) shows the output signal vl of the voltage detection circuit 2 and the output signal v2 of the square wave conversion circuit 3
- FIG.3(b) shows the output signal v3 of the current-to-voltage conversion circuit 5
- FIG. 3(c) shows the output signal P of the selection unit 7 and the output signal s of the low pass filter 8.
- the operational state of the instrument for measuring leakage current can be visually observed with reference to the drawings.
- the output signal vl that is, a sine wave, of the voltage detection circuit 2 is converted into a square wave, shown in FIG. 3(a), by the square wave conversion circuit 3, and is then input to the selection unit 7.
- the output signal v3 that is, a sine wave, of the current-to-voltage conversion circuit 5 has a phase difference of ⁇ with respect to the output signal vl of the voltage detection circuit 2, and is input to the polarity conversion circuit 6 and the selection unit 7.
- the polarity conversion circuit 6 performs conversion on the polarity of the output signal v3 of the current-to-voltage conversion circuit 5, and outputs an output signal ⁇ v3 having a resulting polarity to the selection unit 7.
- the selection unit 7 outputs the output signal v3 of the current-to- voltage conversion circuit 5 when the polarity of the output signal v2 of the square wave conversion circuit 3 is positive (+), and outputs the output signal ⁇ v3 of the polarity conversion circuit 6 when the polarity of the output signal v2 is negative (-).
- the low pass filter 8 passes only low frequency components of the output signal P of the multiplication circuit 6 therethrough, and finally outputs the output signal s , as shown in FIG. 3(c).
- the output signal s of the low pass filter 8 is the ground resistive leakage current Ir . Therefore, unlike the prior art, a complicated process of detecting ground resistive leakage current by dividing the output value of the multiplication circuit by the effective value of the measurement target electric line voltage is not required to be executed, and the circuit configuration of the instrument for measuring a leakage current is considerably simplified.
- circuits subsequent to the low pass filter 8 may be constructed either in an analog manner or in a digital manner, without limitation.
- the instrument for measuring leakage current including a voltage detection circuit 2, a current detection circuit 4, a current-to-voltage conversion circuit 5, and a low pass filter 8, is reinforced with a square wave conversion circuit 3 for converting the output signal vl , that is, a sine wave, from the voltage detection circuit 2 into a square wave, a polarity conversion circuit 6 for converting the polarity of the output signal of the current-to-voltage conversion circuit 5 and outputting a resulting signal, and a selection unit 7 for selectively outputting the output signal of the current-to-voltage conversion circuit 5 or the output signal of the polarity conversion circuit 6 to the low pass filter 8 according to the polarity of the output signal of the square wave conversion circuit 3. Therefore, the output signal 1 ⁇ of the low pass filter 8 can be a ground resistive leakage current Ir , so that there are advantages in that the circuit configuration of the instrument for measuring leakage current is considerably simplified, and ground resistive leakage current can be accurately measured.
Abstract
The present invention discloses an instrument for measuring leakage current, including a voltage detection circuit, a current detection circuit, a current-to-voltage conversion circuit, and a low pass filter, is reinforced with a square wave conversion circuit for converting an output signal, that is, a sine wave, from the voltage detection circuit into a square wave, a polarity conversion circuit for converting a polarity of the output signal of the current-to-voltage conversion circuit and outputting a resulting signal, and a selection unit for selectively outputting the output signal of the current-to-voltage conversion circuit or the output signal of the polarity conversion circuit to the low pass filter according to the polarity of the output signal of the square wave conversion circuit. Therefore, the output signal of the low pass filter can be a ground resistive leakage current, so that there are advantages in that the circuit configuration of the instrument for measuring leakage current is considerably simplified, and ground resistive leakage current can be accurately measured.
Description
[DESCRIPTION] [Invention Title]
MEASURING INSTRUMENT FOR AN ELECTRIC CURRENT LEAKAGE [Technical Field]
The present invention relates, in general, to an instrument for measuring leakage current, and, more particularly, to an instrument for measuring leakage current, which can satisfactorily measure ground resistive leakage current using a simple circuit construction. [Background Art]
As the ground insulation resistance of an alternating current electric line or the ground insulation resistance of an apparatus connected electric line, is deteriorated, leakage current increases, and thus electrical fires or electric shock accidents may occur.
Therefore, in order to prevent these accidents from occurring, leakage current should be accurately measured so that electrical fires or electric shock accidents can be prevented.
Generally, in the measurement of a leakage current, the insulation resistance between a measurement target electric line and ground is measured using a well-known leakage resistance tester in the state in which the supply of power into the measurement target electric line is interrupted.
However, in order to measure leakage current using the leakage resistance tester described above, the supply of power into a measurement target electric line must be interrupted. Therefore, there are problems in that the work of measuring a leakage current is considerably burdensome and inconvenient, and the detection of leakage current cannot be performed in the absence of family members when an electric leakage test is conducted for each family.
In order to solve the above-described problems, a method of measuring the leakage current of a measurement target electric line using a well-known clamp-type current tester in the state in which the supply of power into a measurement target electric line is not interrupted was proposed. The value
of a leakage current measured using this method is a resultant leakage current, in which a ground resistive leakage current is added to a ground capacitive leakage current. Therefore, in the case in which the ground capacitive leakage current is large, the resultant leakage current is large even when the ground resistive leakage current is small, thereby causing a problem of determining electric leakage, even though electric leakage does not occur.
Recently, a method of measuring the resultant leakage current and voltage of a measurement target electric line, and then detecting a ground resistive leakage current using the measured resultant leakage current and voltage in the state in which the supply of power into a measurement target electric line is not interrupted has been proposed.
Such a leakage current tester employs a method of directly multiplying the instantaneous value of a resultant leakage current, measured from a measurement target electric line, by the instantaneous value of voltage, measured from the measurement target electric line, using a multiplier, and then dividing the resulting value by the effective value of the voltage of the measurement target electric line, thereby detecting ground resistive leakage current.
However, such a leakage current tester employs a method of dividing the value obtained through the multiplication of a multiplier by the effective value of the voltage of measurement target electric line, thereby detecting ground resistive leakage current. Therefore, there arises a problem in that the circuit construction of a leakage current tester is considerably complicated.
For reference, it is not difficult to directly multiply the instantaneous value of a resultant leakage current, measured from a measurement target electric line, by the instantaneous value of voltage measured from the measurement target electric line using a multiplier, but it is considerably difficult to perform a process of dividing a value obtained through the multiplication of a multiplier by the effective value of the
voltage of a measurement target electric line, thereby detecting a ground resistive leakage current, in an analog manner.
[Disclosure]
[Technical Problem]
Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and an object of the present invention is to provide an instrument for measuring leakage current, which can satisfactorily measure ground resistive leakage current using a simple circuit construction.
[Technical Solution]
In order to accomplish the above object, the present invention provides an instrument for measuring a leakage current, including a voltage detection circuit for detecting line voltage from a measurement target electric line; a square wave conversion circuit for converting a sine wave, which is the output signal of the voltage detection circuit, into a square wave; a current detection circuit for detecting resultant leakage current from the measurement target electric line; a current-to-voltage conversion circuit for converting the resultant leakage current of the current detection circuit into voltage corresponding to the resultant leakage current; a polarity conversion circuit for converting the polarity of the output signal of the current-to-voltage conversion circuit and outputting the resulting signal; a selection unit for receiving the output signal of the square wave conversion circuit, the output signal of the current-to-voltage conversion circuit and the output signal of the polarity conversion circuit, and selectively outputting the output signal of the current-to-voltage conversion circuit or the output signals of the polarity conversion circuit according to the polarity of the output signal of the square wave conversion circuit; and a low pass filter for passing the low frequency component of the output signal of the selection unit (7) therethrough.
[Description of Drawings]
FIG. 1 is a diagram showing an instrument for measuring leakage current according to the present invention;
FIG. 2 is a vector diagram showing the phase relationship between a resultant leakage current, a ground resistive leakage current, and a ground capacitive leakage current; and
FIG. 3 is a view showing the operational state of the instrument for measuring leakage current according to the present invention.
* Description of reference numerals of principal elements in the drawings *
1: measurement target electric line
2: voltage detection circuit
3: square wave conversion circuit
4: current detection circuit
5: current-to-voltage conversion circuit
6: polarity conversion circuit
T- selection unit
8: low pass filter [Mode for Invention]
Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings.
An instrument for measuring a leakage current according to the present invention, as shown in FIG. 1, includes a voltage detection circuit 2 for detecting line voltage from a measurement target electric line 1, a square wave conversion circuit 3 for converting a sine wave, which is an output signal of the voltage detection circuit 2, into a square wave, a current detection circuit 4 for detecting the resultant leakage current of the measurement target electric line 1, a current-to-voltage conversion circuit 5 for converting the resultant leakage current, output from the current detection circuit 4, into corresponding voltage, a polarity conversion
circuit 6 for changing the polarity of the output signal of the current-to- voltage conversion circuit 5 and outputting a resulting signal, a selection unit 7 for receiving an output signal of the square wave conversion circuit 3, an output signal of the current-to-voltage conversion circuit 5, and an output signal of the polarity conversion circuit 6, and selectively outputting the output signal of the current-to-voltage conversion circuit 5 or the output signal of the polarity conversion circuit 6 according to the polarity of the output signal of the square wave conversion circuit 3, and a low pass filter 8 for passing only the low frequency component of an output signal of the selection unit 7 therethrough.
In this embodiment, a well-known voltage detection circuit, which is connected to the measurement target electric line 1, divides the line voltage of the measurement target electric line 1 and measures the resulting voltages, is used as the voltage detection circuit 2.
A well-known current transformer, which surrounds the measurement target electric line 1 and detects a resultant leakage current, is used as the current detection circuit 4.
Since the square wave conversion circuit 3, the current-to-voltage conversion circuit 5, the polarity conversion circuit 6, the selection unit 7, and the low pass filter 8 are widely known and utilized, detailed descriptions thereof are omitted here.
With reference to FIGS. 2 and 3, the operational state of the instrument for measuring leakage current according to the present invention is described below.
Referring to FIG. 2, it can be seen that the effective value Ir of a ground resistive leakage current has the same phase as the effective value v of a measurement target electric line voltage, the effective value Ic of a ground capacitive leakage current has a phase advanced by 90° with respect to that of the effective value v of the line voltage, and the effective value *S of a resultant leakage current is the vector sum of the effective
.
value Ir of the ground resistive leakage current and the effective value Ic of the ground capacitive leakage current, and has a phase advanced by θ with respect to that of the effective value V of the measurement target electric line voltage.
If the voltage of the measurement target electric line 1 is a sine wave, which does not contain harmonics, the instantaneous value v of the measurement target electric line voltage and the output signal vl of the voltage detection circuit 2 can be expressed by the following Equations 1 and 2.
v=FXV2sin(α)/) (1) where ω=2πf, and J is the frequency of the measurement target electric line.
vl =K\ Xv=Kl X VX yfϊsanζpt) (2) where κι is the gain of the voltage detection circuit 2.
If the polarity of the output signal vl is positive (+), that is, if 0 < ωt < π, the output signal v2 of the square wave conversion circuit 3 is -+--KZ- , If the polarity of the output signal vl is negative (-), that is, if π < ωt < 2π , the output signal v2 is ~κz .
Meanwhile, if the resultant leakage current of the measurement target electric line 1 is a sine wave which does not contain harmonics, the
instantaneous value ** of the resultant leakage current of the measurement target electric line 1, the output signal ih of the current detection circuit
4, and the output signal v3 of the current-to-voltage conversion circuit 5 are expressed by the following Equations 3, 4, and 5.
where ^is the effective value of a resultant leakage current, and θ is the phase angle between the instantaneous value v of the measurement
target electric line voltage and the instantaneous value ** of the resultant leakage current.
where K3 is the current ratio of the current detection circuit 4.
where κ4r is the gain of the current-to-voltage conversion circuit 3. Since the selection unit 7 selects the output signal v3 of the current-to-voltage conversion circuit 5 or the output signal ~v3 of the polarity conversion circuit 6 according to the polarity of the output signal v2 of the square wave conversion circuit 3, the output signal P of the selection unit 7 can be expressed by the following Equation 6 when the polarity of the output signal v2 of the square wave conversion circuit 3 is positive (+), or by the following Equation 7 when the polarity of the output signal v2 of the square wave conversion circuit 3 is negative (-).
p=-K3 XK4 XIgx /2 sin(ωt+Q) (7)
Since the low pass filter 8 filters out all harmonic signals included in the output signal P of the selection unit 7, the output signal s of the low pass filter 8 is a direct current signal corresponding to the average of the output signal P .
Therefore, the output signal s of the low pass filter 8 is expressed by the following Equation 8. )
X -J- ( [-cos(ω/+θ)] 1+ [cos(ω/+θ)] f )
2π
If, in Equation 8, gains K3 and κ4 are adjusted such that
2\/2
, the output signal s of the low pass filter 8 is expressed by the following Equation 9.
S=IgX cosQ=Ir (9)
Therefore, when the voltage detection circuit 2 is connected to the measurement target electric line 1 and the current detection circuit 4 surrounds the measurement target electric line 1, the ground resistive leakage current Ir is output through the low pass filter 8.
FIG. 3(a) shows the output signal vl of the voltage detection circuit 2 and the output signal v2 of the square wave conversion circuit 3, FIG.3(b) shows the output signal v3 of the current-to-voltage conversion circuit 5, and FIG. 3(c) shows the output signal P of the selection unit 7 and the output signal s of the low pass filter 8. The operational state of the instrument for measuring leakage current can be visually observed with reference to the drawings.
First, as shown in FIG. 3(a), the output signal vl , that is, a sine wave, of the voltage detection circuit 2 is converted into a square wave, shown in FIG. 3(a), by the square wave conversion circuit 3, and is then input to the selection unit 7.
Meanwhile, as shown in FIG. 3(b), the output signal v3 , that is, a sine wave, of the current-to-voltage conversion circuit 5 has a phase difference of θ with respect to the output signal vl of the voltage detection circuit 2, and is input to the polarity conversion circuit 6 and the selection unit 7.
The polarity conversion circuit 6 performs conversion on the polarity
of the output signal v3 of the current-to-voltage conversion circuit 5, and outputs an output signal ~v3 having a resulting polarity to the selection unit 7.
The selection unit 7 outputs the output signal v3 of the current-to- voltage conversion circuit 5 when the polarity of the output signal v2 of the square wave conversion circuit 3 is positive (+), and outputs the output signal ~v3 of the polarity conversion circuit 6 when the polarity of the output signal v2 is negative (-).
The low pass filter 8 passes only low frequency components of the output signal P of the multiplication circuit 6 therethrough, and finally outputs the output signal s , as shown in FIG. 3(c).
As described above, the output signal s of the low pass filter 8 is the ground resistive leakage current Ir . Therefore, unlike the prior art, a complicated process of detecting ground resistive leakage current by dividing the output value of the multiplication circuit by the effective value of the measurement target electric line voltage is not required to be executed, and the circuit configuration of the instrument for measuring a leakage current is considerably simplified.
Since the output signal ^ of the low pass filter 8 is an analog signal, circuits subsequent to the low pass filter 8 may be constructed either in an analog manner or in a digital manner, without limitation.
As described above, the present invention is not limited to the configuration and operation illustrated and described in the preferred embodiment, but various modifications can be made without departing from the scope of the attached claims. [Industrial Applicability]
According to the above-described present invention, the instrument for measuring leakage current, including a voltage detection circuit 2, a current detection circuit 4, a current-to-voltage conversion circuit 5, and a low pass filter 8, is reinforced with a square wave conversion circuit 3 for
converting the output signal vl , that is, a sine wave, from the voltage detection circuit 2 into a square wave, a polarity conversion circuit 6 for converting the polarity of the output signal of the current-to-voltage conversion circuit 5 and outputting a resulting signal, and a selection unit 7 for selectively outputting the output signal of the current-to-voltage conversion circuit 5 or the output signal of the polarity conversion circuit 6 to the low pass filter 8 according to the polarity of the output signal of the square wave conversion circuit 3. Therefore, the output signal 1^ of the low pass filter 8 can be a ground resistive leakage current Ir , so that there are advantages in that the circuit configuration of the instrument for measuring leakage current is considerably simplified, and ground resistive leakage current can be accurately measured.
Claims
[Claim 1]
An instrument for measuring a leakage current, comprising: a voltage detection circuit for detecting electric line voltage from a measurement target electric line! a square wave conversion circuit for converting a sine wave, which is an output signal of the voltage detection circuit, into a square wave; a current detection circuit for detecting a. resultant leakage current from the measurement target electric line; a current-to-voltage conversion circuit for converting the resultant leakage current of the current detection circuit into voltage corresponding to the resultant leakage current; a polarity conversion circuit for converting a polarity of an output signal of the current-to-voltage conversion circuit and outputting a resulting signal; a selection unit for receiving an output signal of the square wave conversion circuit, an output signal of the current-to-voltage conversion circuit, and an output signal of the polarity conversion circuit, and selectively outputting the output signal of the current-to-voltage conversion circuit or the output signal of the polarity conversion circuit.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| KR1020060073443A KR100771939B1 (en) | 2006-08-03 | 2006-08-03 | Measuring instrument for an electric current leakage |
| KR10-2006-0073443 | 2006-08-03 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| WO2008016274A1 true WO2008016274A1 (en) | 2008-02-07 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| PCT/KR2007/003732 WO2008016274A1 (en) | 2006-08-03 | 2007-08-02 | Measuring instrument for an electric current leakage |
Country Status (2)
| Country | Link |
|---|---|
| KR (1) | KR100771939B1 (en) |
| WO (1) | WO2008016274A1 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| 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 |
| WO2019187817A1 (en) * | 2018-03-29 | 2019-10-03 | オムロン株式会社 | Insulation measurement device and insulation measurement method |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106226605B (en) * | 2016-07-20 | 2019-08-13 | 中国航空工业集团公司航空动力控制系统研究所 | A kind of PWM self-sensing method |
| KR101806848B1 (en) | 2017-10-30 | 2017-12-11 | 주식회사 티피티 | Electric leakage protecting apparatus for submerged pump of Non-Grounded type |
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| JPH07253444A (en) * | 1994-03-15 | 1995-10-03 | Mitsubishi Denki Bill Techno Service Kk | Insulation diagnostic apparatus for power cable |
| JPH07311230A (en) * | 1994-05-18 | 1995-11-28 | Sumitomo Electric Ind Ltd | Method and device for monitoring insulation, which monitor insulating state of power cable in hot-line state |
| JP2005227132A (en) * | 2004-02-13 | 2005-08-25 | Meidensha Corp | Insulation condition monitoring apparatus and insulation condition monitoring method |
| KR200401675Y1 (en) * | 2005-08-26 | 2005-11-21 | 김보경 | Low Voltage On-Line Insulation Monitoring System |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| KR19990085704A (en) * | 1998-05-21 | 1999-12-15 | 장정곤 | Digital relay measuring device |
| US6744268B2 (en) * | 1998-08-27 | 2004-06-01 | The Micromanipulator Company, Inc. | High resolution analytical probe station |
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- 2006-08-03 KR KR1020060073443A patent/KR100771939B1/en active IP Right Grant
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2007
- 2007-08-02 WO PCT/KR2007/003732 patent/WO2008016274A1/en active Application Filing
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| Publication number | Priority date | Publication date | Assignee | Title |
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| JPH07253444A (en) * | 1994-03-15 | 1995-10-03 | Mitsubishi Denki Bill Techno Service Kk | Insulation diagnostic apparatus for power cable |
| JPH07311230A (en) * | 1994-05-18 | 1995-11-28 | Sumitomo Electric Ind Ltd | Method and device for monitoring insulation, which monitor insulating state of power cable in hot-line state |
| JP2005227132A (en) * | 2004-02-13 | 2005-08-25 | Meidensha Corp | Insulation condition monitoring apparatus and insulation condition monitoring method |
| KR200401675Y1 (en) * | 2005-08-26 | 2005-11-21 | 김보경 | Low Voltage On-Line Insulation Monitoring System |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
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| 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 |
| WO2019187817A1 (en) * | 2018-03-29 | 2019-10-03 | オムロン株式会社 | Insulation measurement device and insulation measurement method |
| JP2019174385A (en) * | 2018-03-29 | 2019-10-10 | オムロン株式会社 | Insulation measuring device and insulation measuring method |
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| KR100771939B1 (en) | 2007-10-31 |
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