KR20110105963A - Apparatus for predicting defect location of cable and method thereof - Google Patents

Apparatus for predicting defect location of cable and method thereof Download PDF

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Publication number
KR20110105963A
KR20110105963A KR1020100025118A KR20100025118A KR20110105963A KR 20110105963 A KR20110105963 A KR 20110105963A KR 1020100025118 A KR1020100025118 A KR 1020100025118A KR 20100025118 A KR20100025118 A KR 20100025118A KR 20110105963 A KR20110105963 A KR 20110105963A
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South Korea
Prior art keywords
cable
defect
ultrasonic sensors
signal
metal foil
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KR1020100025118A
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Korean (ko)
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김영홍
김정년
이동근
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엘에스전선 주식회사
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Priority to KR1020100025118A priority Critical patent/KR20110105963A/en
Priority to PCT/KR2011/001551 priority patent/WO2011118923A2/en
Publication of KR20110105963A publication Critical patent/KR20110105963A/en

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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
    • G01R31/12—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing
    • G01R31/1209—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing using acoustic measurements
    • 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
    • G01R31/08—Locating faults in cables, transmission lines, or networks
    • G01R31/081—Locating faults in cables, transmission lines, or networks according to type of conductors
    • G01R31/083—Locating faults in cables, transmission lines, or networks according to type of conductors in cables, e.g. underground

Abstract

Disclosed are a defect location estimating apparatus for a cable, and a method thereof. The apparatus for estimating a defect location of a cable includes a sensor unit including a metal foil sensor measuring an electrical signal generated from a cable and ultrasonic sensors installed on the cable to measure ultrasonic signals generated from the cable; And a defect position estimating unit estimating a defect position of the cable by using the partial discharge signal measured by the metal foil sensor and the partial discharge signals measured by the ultrasonic sensors. A method of estimating a defect location of a cable includes measuring a partial discharge signal in the form of an electrical pulse with respect to the cable through a metal foil sensor, and measuring the partial discharge signals in the form of an ultrasonic pulse through ultrasonic sensors installed on a surface of the cable; And (b) estimating a defect position of the cable by using the signal measured by the metal foil sensor and the signals measured by the ultrasonic sensors. According to this structure, the exact position of a defect can be known by minimizing the error with respect to the estimated position of a defect.

Description

Device for estimating defect location of cable and its method {APPARATUS FOR PREDICTING DEFECT LOCATION OF CABLE AND METHOD THEREOF}

The present invention relates to a technique for estimating a defect location of a cable, and more particularly, to an apparatus and method for estimating a location of a defect on a cable by measuring a partial discharge signal.

In general, the detection of defects in the ultra-high voltage cable is to inspect the inside of the cable insulator for the presence of foreign matter or interface, etc., and it can be performed during manufacturing, quality inspection, testing for defect detection, or during operation after installation on site. have. The inspection process determines whether there is a problem with the cable and if there is a problem with the cable, the intermediate quality inspection is performed in parallel, and according to the result, the work is progressed and the quality of the product is judged. The basic method to check the cable for defects is to find the defects with the naked eye, and to observe the defects found through the microscope to determine the actual size, shape and type of the defects to determine the abnormality. . However, if only visual inspection is performed, subjective deviation due to operator's experience difference is severe, and accurate quality inspection is difficult.

In order to improve this, a position estimation method through electrical pulse measurement has been introduced. In the position estimation method using electrical pulse measurement, as shown in FIG. 1, after the sensors capable of measuring the electrical pulses are installed at the same positions C110 and C120 on both sides of the cable, the sensor in case of partial discharge due to defect C130 is installed. This method estimates the location of a defect by using the difference of arrival times (t 1 , t 2 ) of electrical pulses measured through the signals.

Equation 1 below is to find the distance between the defect and the sensor.

Figure pat00001

Here, ｘ 1 is the distance between the defect and the sensor installed on one side (C110), ｘ is the distance between the sensors installed on both sides (C110, C120), ν is the transmission speed of the electrical pulse, Δt is the time difference of arrival of the signals (│ t 1 -t 2 |

However, in the conventional position estimation method using electrical pulse measurement, since the transmission speed of the electrical pulse is close to the speed of light, a large error occurs in the distance between the defect and the sensor even with a small error in the time difference of arrival. There was a problem that it is difficult to determine the exact location.

The present invention has been proposed to solve the problems of the prior art as described above, the object of which is to determine the exact position of the defect by minimizing the error to the estimated position of the defect and its apparatus In providing a method.

The technical problem to be achieved by the present invention is not limited to the technical problem mentioned above, and other technical problems not mentioned above may be clearly understood by those skilled in the art from the following description. There will be.

The apparatus for estimating a defect position of a cable according to the present invention includes a sensor unit including a metal foil sensor measuring an electrical signal generated from a cable and ultrasonic sensors installed on the cable to measure ultrasonic signals generated from the cable; And a defect position estimating unit estimating a defect position of the cable by using the partial discharge signal measured by the metal foil sensor and the partial discharge signals measured by the ultrasonic sensors.

Meanwhile, the method for estimating a defect location of a cable according to the present invention measures a partial discharge signal in the form of an electrical pulse with respect to the cable through a metal foil sensor, and receives the partial discharge signals in the form of an ultrasonic pulse through ultrasonic sensors installed on the surface of the cable. Measuring (a); And (b) estimating a defect location of the cable by using the signal measured by the metal foil sensor and the signals measured by the ultrasonic sensors.

According to the present invention, it is possible to provide an apparatus and method for estimating a defect position of a cable so that the exact position of the defect can be known by minimizing an error with respect to the estimated position of the defect.

In addition, according to the present invention, the position of a defect can be known by a simple process of measuring a single discharge signal, and can be applied to various forms such as cylinders, spheres, cubes, etc., rather than the structure of a line having a very long length compared to the width. An apparatus and method for estimating a defect location of a cable can be provided.

1 is a view for explaining a defect detection method according to the prior art.
2 is a block diagram of an apparatus for estimating a defect location of a cable according to an embodiment of the present invention.
3 and 4 are views for explaining the operation of the defect position estimation apparatus shown in FIG.
5 is a flowchart illustrating a method for estimating a defect location of a cable according to an embodiment of the present invention.

Hereinafter, an apparatus and a method for estimating a defect position of a cable according to a preferred embodiment of the present invention will be described in detail with reference to FIGS. 2 to 5.

2 is a configuration diagram of a defect location estimating apparatus for a cable according to an embodiment of the present invention, and FIGS. 3 and 4 are diagrams for describing an operation of the defect position estimating apparatus shown in FIG. 2.

Referring to FIG. 2, the apparatus for estimating a defect location includes a sensor unit 200 having large sensors and measuring a distance between defects and sensors in pulses measured by the sensor unit 200. It is divided into a defect location estimation unit 300 that calculates the location of the defect in three dimensions by applying a measurement method.

The sensor unit 200 includes a metal foil sensor 201 and ultrasonic sensors 210, 220, and 230. The metal foil sensor 201 is installed to surround both positions of the cable separated by a predetermined distance in the form of a thin metal foil (foil-electrode), and measures an electrical signal generated from the cable and transmits it to the defect position estimator 300. The ultrasonic sensors 210, 220, and 230 are installed on the surface of the cable, and each of the ultrasonic sensors 210, 220, and 230 measures the ultrasonic signals generated from the cable and transmits the ultrasonic signals to the defect location estimator 300. . In the embodiment shown in FIG. 2, there are three ultrasonic sensors 210, 220, 230, and are respectively installed in spaced positions on the cable surface to be located on the same plane.

When the partial discharge signal due to the defect C210 occurs in the cable, the defect location estimator 300 may detect the partial discharge signal and the ultrasonic sensors 210, 220, and 230 in the form of an electrical pulse measured by the metal foil sensor 201. Partial discharge signals in the form of ultrasonic waves are measured and the defect location of the cable is estimated.

The defect position estimating unit 300 includes a power supply unit 310, a signal arrival time measuring unit 320, a distance converting unit 330, and a defect position calculating unit 340.

The power supply unit 310 applies a test voltage to the cable to be a sample in order to detect a defect. When the test voltage is applied to the cable, a partial discharge signal is generated at a portion having a defect (C210), and the partial discharge signal is transmitted through the metal foil sensor 201 and the ultrasonic sensors 210, 220, and 230 connected to the cable. Is measured.

The signal arrival time measuring unit 320 receives the partial discharge signal measured by the metal foil sensor 201 and the ultrasonic sensors 210, 220, and 230, and thus the ultrasonic sensor based on the signal arrival time t 0 of the metal foil sensor 201. The signal arrival times t 1 , t 2 and t 3 for each of these signals are measured. And, the time difference of arrival Δt 1 , Δt 2 between the signal measured by the metal foil sensor 201 using the signal arrival times t 1 , t 2 , t 3 and the signals measured by the ultrasonic sensors 210, 220, 230. , Δt 3 is calculated and output to the distance conversion unit 330.

FIG. 3 shows the partial discharge signals G210, G220, and the ultrasonic wave measured by the ultrasonic sensors 210, 220, and 230 after the partial discharge signal G200 of the electrical pulse type measured by the metal foil sensor 201 is received. When G230 arrives, the time difference difference Δt 1 , Δt 2 , Δt 3 between the signals G210, G220, and G230 measured by the ultrasonic sensors 210, 220, and 230 are illustrated.

The distance conversion unit 330 multiplies the signal transmission speed v of the cable by the time difference of arrival Δt 1 , Δt 2 , Δt 3 calculated by the signal arrival time measurement unit 320 and the defects and the ultrasonic sensors 210, 220, and 230. Calculate the distances r 1 , r 2 and r 3 . The signal transfer rate v is a value determined according to the type of medium (eg, whether the medium is water or rubber). For example, when the cable is a rubber molded (PMJ) connection member, the signal transmission speed v is a speed at which a signal is transmitted in a rubber material, which is about 1 km / s, and a signal of the ultrasonic sensors 210, 220, and 230. The distance r 1 , r 2 , and r 3 between the defects and the ultrasonic sensors 210, 220, and 230 are calculated by multiplying the difference of arrival times Δt 1 , Δt 2 , and Δt 3 by 1 km / s. r 1 , r 2 , and r 3 are concepts in which the time difference of arrival of the ultrasonic signals based on the arrival time of the electrical signal is converted into a distance.

Since the transmission speed of the electrical signal is considerably faster than the ultrasonic signal, a large error does not occur even if the distance between the defect C210 and the metal foil sensor 201 is ignored. The distance r obtained by multiplying the time difference of arrival Δt 1 , Δt 2 , Δt 3 of the signals measured by the ultrasonic sensors 210, 220, 230 and the propagation speed v of the ultrasonic signal in the material constituting the cable (for example, rubber). When three spheres are formed around each of the ultrasonic sensors 210, 220, and 230 as 1 , r 2 , and r 3 , defects C210 exist at the intersections of the spheres.

The defect location calculator 340 derives the three-dimensional coordinates (X, Y, Z) of the defect by applying the distances r 1 , r 2 , r 3 calculated by the distance converter 330 to the trilateral measurement method.

FIG. 4 calculates the distances r 1 , r 2 , r 3 between the defects and the sensors 210, 220, 230 as described above, and applies the three-side measurement method defined as Equations 2 and 3 to the defects. It illustrates the process of obtaining the three-dimensional position of.

Figure pat00002

Figure pat00003

Figure pat00004

Figure pat00005

Figure pat00006

Figure pat00007

Ultrasonic sensors (210, 220, 230) are installed on the surface of the cable so that they are on the same plane to obtain the position of the defect using trilateral measurement. The coordinates of the defect are calculated by calculating three-dimensional coordinates (X, Y, Z) is obtained in the form. In FIG. 4, the ultrasonic sensors 210, 220, 230 are located at the coordinates of P1 (0,0,0), P2 (2r, 0,0), P3 (2r, a, 0), and defects and sensors By calculating the distances r 1 , r 2 , and r 3 between the fields 210, 220, and 230, Fault (X, Y, Z), which is a three-dimensional coordinate of the defect, can be obtained.

The cable that is the target of defect detection has a thickness of a certain value or more than a general household cable, it is effective in the application of one embodiment that a cable that generates a signal size that can be estimated when the test voltage is applied. Ultra-high voltage cables, such as a rubber integrated connection material, fall into this object.

5 is a flowchart illustrating a method for estimating a defect location of a cable according to an embodiment of the present invention.

When a test voltage is applied to the cable to be a sample (S110), if a defect exists in the cable, a partial discharge signal is generated at the defective portion (S120).

As described in FIG. 2, in one embodiment, three ultrasonic sensors 210, 220, and 230 are installed on the same plane on the surface of the cable. As the test voltage is applied to the cable, the metal foil sensor 201 measures a partial discharge signal in the form of an electrical pulse generated by a defect in the cable, and the three ultrasonic sensors 210, 220, and 230 installed on the surface of the cable Measure the partial discharge signal in the form of ultrasonic pulses.

The defect location estimating apparatus estimates a defect location of a cable by using the signal measured by the metal foil sensor 201 and the signals measured by the ultrasonic sensors 210, 220, and 230. The defect location estimation process may be subdivided into S130 to S170.

If a defect is present in the cable and a partial discharge signal is generated, the defect location estimating apparatus measures the partial discharge signal through the metal foil sensor 201 and the ultrasonic sensors 210, 220, and 230, and then detects the signal of the metal foil sensor 201. The signal arrival times t 1 , t 2 , and t 3 of the ultrasonic sensors 210, 220, and 230 are measured based on the arrival times t 0 (S130 and S140). Then, the time difference of arrival Δt 1 , Δt 2 , Δt between the signal of the metal foil sensor 201 and the signals of the ultrasonic sensors 210, 220, 230 using the measured signal arrival times t 1 , t 2 , t 3 . Calculate 3 (S150).

After the difference in the signal arrival time between the metal foil sensor 201 and the ultrasonic sensors 210, 220, 230 is calculated (S150), the defect position estimating device calculates the difference of the cable to the calculated arrival time difference Δt 1 , Δt 2 , Δt 3 . The distance r 1 , r 2 , and r 3 between the defect and the ultrasonic sensors 210, 220, and 230 are calculated by multiplying the signal transmission speed v (S160).

Thereafter, the defect location estimating apparatus calculates the three-dimensional coordinates (X, Y, Z) of the defect by applying the calculated distances r 1 , r 2 , r 3 to the trilateral measurement method (S170). Once the location of the defect is calculated, the operator will be able to check the calculated location of the cable with the naked eye or with equipment such as a microscope to more accurately recognize the actual presence, location and type of the defect and take further action.

According to the above-described embodiment, since only one partial discharge pulse is needed to locate the defect, only one test can determine the exact position of the defect. In addition, since the transmission speed of the ultrasonic signals is considerably slower than in the case of electromagnetic waves, the errors generated in the calculation of the distance between the ultrasonic signals and the defects due to the time difference between the ultrasonic signals are considerably smaller, thereby ensuring high accuracy in estimating the defect position. Can be. In addition, there is an advantage that can be easily applied to all forms, such as cylindrical, sphere, hexahedron rather than the structure is significantly longer than the width.

Although the embodiments of the present invention have been described above with reference to the accompanying drawings, those skilled in the art to which the present invention pertains may implement the present invention in other specific forms without changing the technical spirit or essential features thereof. I can understand that.

Therefore, since the embodiments described above are provided to completely inform the scope of the invention to those skilled in the art, it should be understood that they are exemplary in all respects and not limited. The invention is only defined by the scope of the claims.

200: sensor unit 201: metal foil sensor
210, 220, 230: ultrasonic sensor 300: defect location estimation unit
310: power supply unit 320: signal arrival time measurement unit
330: distance conversion unit 340: defect location calculation unit

Claims (7)

A sensor unit including a metal foil sensor measuring electrical signals generated from a cable and ultrasonic sensors installed on the cable to measure ultrasonic signals generated from the cable; And
And a defect position estimator for estimating a defect position of the cable by using the partial discharge signal measured by the metal foil sensor and the partial discharge signals measured by the ultrasonic sensors. The method of claim 1,
The ultrasonic sensors are three, the defect position estimation device, characterized in that installed on the surface of the cable to be located on the same plane. The method of claim 2, wherein the defect position estimating unit,
As the test voltage is applied to the cable, a partial discharge signal is received from the metal foil sensor and the ultrasonic sensors and the signal arrival time t 1 , t of each of the ultrasonic sensors based on the signal arrival time t 0 of the metal foil sensor. 2, to measure t 3, and calculating the signal arrival time of t 1, t 2, is reached by using the t 3 between the signals of the signals and the ultrasonic sensor of the metal foil sensor time differences Δt 1, Δt 2, Δt 3 A signal arrival time measuring unit;
The distance between the defects and the ultrasonic sensors r 1 , r 2 , and r 3 is calculated by multiplying the signal propagation speed v of the cable by the arrival time differences Δt 1 , Δt 2 , Δt 3 calculated by the signal arrival time measuring unit. Conversion unit; And
The defect position of the cable including a defect position calculation unit for calculating the three-dimensional coordinates (X, Y, Z) of the defect by applying the distance r 1 , r 2 , r 3 calculated through the distance conversion unit to a three-side measurement method Estimation device. Measuring a partial discharge signal in the form of an electrical pulse with respect to the cable through a metal foil sensor, and measuring the partial discharge signals in the form of an ultrasonic pulse through ultrasonic sensors installed on the surface of the cable; And
Estimating a defect location of the cable by using the signal measured by the metal foil sensor and the signals measured by the ultrasonic sensors (b). The method of claim 4, wherein
3. The method of estimating a defect location of a cable according to claim 1, wherein three ultrasonic sensors are disposed on the same plane. The method of claim 5, wherein step (a) comprises:
As the test voltage is applied to the cable, the metal foil sensor measures a partial discharge signal in the form of an electrical pulse generated due to the defect of the cable; And
When the test voltage is applied to the cable, the three ultrasonic sensors comprising the step of measuring a partial discharge signal in the form of ultrasonic pulses. The method of claim 5, wherein step (b) comprises:
Receiving a partial discharge signal from the metal foil sensor and the ultrasonic sensors and measuring signal arrival times t 1 , t 2 , t 3 of each of the ultrasonic sensors based on the signal arrival time t 0 of the metal foil sensor;
Calculating a time difference Δt 1 , Δt 2 , Δt 3 between the signal of the metal foil sensor and the signals of the ultrasonic sensors using the measured signal arrival times t 1 , t 2 , t 3 ;
Calculating distances r 1 , r 2 , r 3 between the defects and the ultrasonic sensors by multiplying the calculated transmission time difference Δt 1 , Δt 2 , Δt 3 by the signal transmission speed v of the cable; And
Calculating the three-dimensional coordinates (X, Y, Z) of the defect by applying the calculated distances r 1 , r 2 , r 3 to a three-sided measurement method.
KR1020100025118A 2010-03-22 2010-03-22 Apparatus for predicting defect location of cable and method thereof KR20110105963A (en)

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KR101364114B1 (en) * 2012-10-09 2014-02-20 주식회사 효성 Method for detecting partial discharge point
CN106054045A (en) * 2016-08-16 2016-10-26 安徽众升电力科技有限公司 Partial discharge detection device
KR20190055639A (en) * 2017-11-15 2019-05-23 주식회사 다스코포레이션 Sensing apparatus for monitoring real-time fault diagnosis of self-generating high pressure transmission dc cable, monitoring system and method for the same

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DE102017207818B3 (en) 2017-05-09 2018-05-30 Siemens Aktiengesellschaft Method and device for locating an electrical discharge in an electrical system
FR3074583B1 (en) * 2017-12-01 2019-11-29 Commissariat A L'energie Atomique Et Aux Energies Alternatives METHOD FOR DETECTING A FAULT IN A CABLE
CN108828015B (en) * 2018-09-10 2021-04-13 西南石油大学 Method and device for positioning local weak physical damage of cable
EP3943957A1 (en) * 2020-07-20 2022-01-26 ABB Schweiz AG Method for detecting an electrical discharge in an electrical apparatus and system therefor

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JPH05328582A (en) * 1992-05-19 1993-12-10 Furukawa Electric Co Ltd:The Metallic pipe for connection of power cable
JP2978717B2 (en) * 1994-06-16 1999-11-15 株式会社フジクラ Attaching foil electrode for partial discharge measurement to insulated connection of power cable
JP3756473B2 (en) * 2002-07-30 2006-03-15 Ｊｆｅアドバンテック株式会社 Method and apparatus for detecting partial discharge in insulator of power equipment

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KR101364114B1 (en) * 2012-10-09 2014-02-20 주식회사 효성 Method for detecting partial discharge point
WO2014058173A1 (en) * 2012-10-09 2014-04-17 주식회사 효성 Method of detecting partial discharging location of power device
US9658273B2 (en) 2012-10-09 2017-05-23 Hyosung Corporation Method of detecting partial discharging location of power device
CN106054045A (en) * 2016-08-16 2016-10-26 安徽众升电力科技有限公司 Partial discharge detection device
KR20190055639A (en) * 2017-11-15 2019-05-23 주식회사 다스코포레이션 Sensing apparatus for monitoring real-time fault diagnosis of self-generating high pressure transmission dc cable, monitoring system and method for the same

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