JP3468012B2 - Detection method of insulation breakdown position of cable line - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for detecting a dielectric breakdown position of a cable line, and particularly to an insulation connection part (IJB).
A method for detecting the dielectric breakdown position of long-distance cable lines.

[0002]

2. Description of the Related Art As a conventional method for detecting a dielectric breakdown position of a cable line, there is, for example, a method disclosed in Japanese Utility Model Laid-Open No. 4-59483. This cable line insulation breakdown position detection method is one in which optical magnetic field sensors that detect surge currents by magnetic fields are provided at both ends of the cable line, and these optical magnetic field sensors are connected to a measuring instrument via an optical fiber cable. Is. This measuring device consists of a light source, photoelectric conversion element, A /
It is composed of a D converter, a memory circuit and a CPU. When insulation breakdown occurs in the cable line, the surge current generated at the location where the insulation breakdown occurs is detected by the optical magnetic field sensors at both ends, and the detected surge current waveform is sent to the measuring instrument via the optical fiber cable. The surge current waveform of the optical magnetic field sensor is input to the photoelectric conversion element of the measuring instrument, converted into digital data by the A / D converter, and stored in the memory circuit. The dielectric breakdown position is detected based on the surge current waveform of the digital data stored in the memory circuit.

[0003]

However, according to the conventional method for detecting the dielectric breakdown position of a cable line, optical magnetic field sensors for detecting a surge current are arranged at both ends of the cable line,
The output of the optical magnetic field sensor detects the dielectric breakdown position based on the surge current waveform after it is transmitted by the optical fiber cable, so the accurate dielectric breakdown position in the long-distance cable line with multiple connection parts can be determined. The problem is that it is difficult to detect. There is also a problem that it is necessary to keep the system in operation at all times. Further, when a dielectric breakdown accident occurs, electromagnetic energy is disturbed by its enormous energy, which makes normal operation of the measurement system difficult and often causes malfunction.

Therefore, the object of the present invention is to reduce malfunctions even in long-distance cable lines with a simple structure.
Another object of the present invention is to provide a method for detecting a dielectric breakdown position of a cable line that can detect the dielectric breakdown position with high accuracy.

[0005]

In order to achieve the above-mentioned object, the present invention provides a long-distance cable line connected by a plurality of insulating connections, wherein the sheaths on both sides of the insulating cylinder of the plurality of insulating connections are provided. detecting a salicylate over di of electrical energy generated from the metal foil electrodes provided outside during breakdown, before Symbol
It converted from surge resistance electrical energy by extracting the high-frequency surge of electrical energy to the unipolar pulsed current, the monopolar
Save capable d sexual pulse current for each of the plurality of insulating the connecting portion
Converted into energy and recorded, and for each of the multiple insulated connections
To read out the recorded energy, broken insulation in the insulated connection part based on the intensity of the energy <br/> Energy that the read
A method for detecting a dielectric breakdown position of a cable line for detecting whether or not breakage has occurred .

Further, in order to achieve the above object, the present invention is a metal foil which is connected by a plurality of insulating connecting portions and is provided outside the sheath on both sides of the insulating cylinder of the plurality of insulating connecting portions.
The partial discharge energy is detected from the electrode and the partial discharge energy is detected.
Converting the energy into a first light energy, the first light energy
Energy is centralized by a fiber optic cable
In the long-distance cable line that transmits to the sight, the metal
Lusa over di resistant electrical energy resulting from the foil electrode during breakdown
The Detects, before converting the hexa over di of electrical energy by extracting the high-frequency surge of electrical energy to the unipolar pulsed current, the unipolar pulsed current said plurality of insulating connecting portions each
Converted into energy that can be stored and recorded ,
Reading the recorded energy for each insulating connection portion into a <br/> second light energy, before Symbol second optical energy
Was transmitted by the optical fiber cable to said common central monitoring stations, the first in the common central monitoring stations
Partial discharge at the insulation connection based on light energy
Detected and based on the intensity of said second light energy
A method for detecting a dielectric breakdown position of a cable line is provided, which detects whether or not a dielectric breakdown occurs in the insulation connection portion .

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 1 shows a cable line of the present invention.
In the first embodiment to which the dielectric breakdown position detection method is applied,
2 shows an outline of a dielectric breakdown position detection system. This system
The length of the cable is the length of the long-distance cable line 1.
Number of insulated connections 2 (2₁, 2₂,… 2 _n), Dielectric breakdown
Detection circuit 3 (3₁, 3₂,… 3_n) Respectively,
Connect each insulation breakdown detection circuit 3 to the optical fiber cable 4 (4₁，
Four₂, ... 4_n) To the central monitoring station 5
It was

The insulating connecting portion 2 is provided with metal foil electrodes 2c, 2c outside the sheath 2b located on both sides of the insulating tube 2a,
The metal foil electrodes 2c, 2c are connected to the dielectric breakdown detection circuit 3 by the lead wires 2d, 2d.

The dielectric breakdown detection circuit 3 includes a bandpass filter (BPF) 30, a double wave detector (rectifier) 31, and
An integrating circuit 32 mainly composed of a capacitor, a magnetic hold unit 33, a degaussing circuit 34, and a magnetoresistive effect element 3
5, a light emitting diode 36, a magnetoresistive element 35, and a DC power source 3 connected in series with the light emitting diode 36.
7 and the surge electric energy generated between the metal foil electrodes 2c of the insulated connection portion 2 (hereinafter referred to as "surge energy").
Abbreviated. ) Is to be detected. In addition, the detection of surge energy is basically the same as the detection of a minute partial discharge pulse (Katsuda, Endo, et al .: 3) Development ”, Electron Theory, Vol. 111-B, No. 11, P1223.
Nov. , 1991).

FIG. 2 shows details of the dielectric breakdown detection circuit 3.

Bandpass filter (BPF) 30
Are capacitors 30a, 30a and high-frequency coil 30.
It consists of b. Capacitance between the sheath 2b and the metal foil electrode 2c, and B. P. F. A predetermined high frequency component in the surge energy, for example, a 30 MHz component is detected by 30. When a dielectric breakdown accident occurs, for example, surge energy propagates also to another insulating connection portion 2 adjacent to the insulation connection several hundred meters apart. However, by limiting the frequency component of the detected surge energy to only the high frequency component, the high frequency component is Since it abruptly attenuates, the amount of energy that reaches the adjacent insulating connection portion 2 becomes small, so that it becomes easy to distinguish between the insulating connection portion 2 that has caused the dielectric breakdown and the normal insulating connection portion 2 that has not caused the dielectric breakdown. , It is possible to detect the accurate insulation breakdown position.

The magnetic hold portion 33 includes a magnetic steel piece 33a,
A yoke 33b that makes the magnetic poles of the magnetic steel piece 33a a closed loop;
An exciting coil 33c for magnetizing the magnetic steel piece 33a is provided. The magnetic steel piece 33a can be magnetized in the same manner as the recording of the lightning current (The Institute of Electrical Engineers of Japan: "Handbook of Electrical Engineering", P1301, February 1985).

The degaussing circuit 34 is a magnetized steel piece 33 that has been magnetized once.
A degaussing coil 34a for degaussing a and a drive circuit 34b for driving the degaussing coil 34a by inputting a degaussing signal are provided.

The magnetoresistive effect element 35 is arranged on the circumference of the magnetic steel piece 33a or between the magnetic steel piece 33a and the yoke 33b, and has a characteristic that electric resistance increases due to a magnetic field.

The centralized monitoring station 5 has a photodiode 50 which receives an optical signal from the light emitting diode 36 via the optical fiber cable 4 and a surge energy intensity display section 51 which displays the surge energy intensity corresponding to the photocurrent of the photodiode 50. And a DC power supply 52 connected in series with the photodiode 50 and the surge energy intensity display section 51.
It has and.

Next, the operation of the system according to the first embodiment will be described. During operation, for example, when a dielectric breakdown accident occurs at the insulation connection portion 2 ₁ shown by X in FIG. 1, a strong low-frequency to high-frequency wide band is provided between the metal foil electrodes 2c and 2c of the insulation connection portion 2 _1. A surge voltage (surge energy) including the frequency component of is generated. The 30 MHz component in this surge energy is the sheath 2b and the metal foil electrode 2c.
And B. and B. P. F. It is detected based on the pass band defined by 30. The detected surge energy is detected (rectified) by the double-wave detector (rectifier) 31 and converted into a unipolar pulse current. The unipolar pulse current changes to a pulse current that is slow to some extent in the integrating circuit 32 and flows into the exciting coil 33c. Magnetic steel piece 33a
Is magnetized in accordance with the magnitude of the pulse current flowing through the exciting coil 33c. The magnetoresistive effect element 35 is a magnetic steel piece 33a.
The electric resistance increases due to the magnetic field according to the strength of magnetization of.
Due to this increase in resistance, the current of the light-emitting diode 36 which is supplied with a DC voltage from the DC power supply 37 and emits light decreases, and the light emission intensity of the light-emitting diode 36 decreases. The light emitting diode 36 transmits an optical signal having a light intensity proportional to the intensity of magnetization to the centralized monitoring station 5 via the optical fiber cable 4. The photodiode 50 of the centralized monitoring station 5 receives the optical signal from the light emitting diode 36, the direct current power is supplied, and the current of the surge energy intensity display section 51 which emits light with a predetermined brightness is lowered and the brightness is lowered. It gets dark.

On the other hand, the surge energy is propagated to the adjacent insulation connection portion 2 ₂ while being attenuated from the insulation connection portion 2 ₁ that has undergone insulation breakdown, and the brightness of the corresponding surge energy intensity display portion 51 is similarly reduced. . In addition, the surge energy hardly propagates to the insulation connection portion 2 _n sufficiently separated from the insulation connection portion 2 _{1 in} which the insulation breakdown has occurred, and the brightness of the corresponding surge energy intensity display portion 51 hardly changes.

On the side of the centralized monitoring station 5, by comparing the brightness of the surge energy intensity display parts 51 corresponding to the respective insulation connection parts 2, the insulation connection part 2 ₁ having the largest surge energy, that is, the position where the dielectric breakdown occurred. The close insulation connection portion 2 ₁ is specified and the dielectric breakdown occurrence position is detected.

After detecting the position where the dielectric breakdown occurs, the degaussing signal is input from the centralized monitoring station 5 to the drive circuit 34b of the degaussing circuit 34 corresponding to each insulating connection 2. Drive circuit 34b
Is a magnetic steel piece 33 that is magnetized by driving the degaussing coil 34a.
Degauss a.

The system according to the first embodiment has the following effects. (A) The generated surge energy is converted into magnetic energy and held in the magnetic steel piece 33a, so that the structure is simple, the reliability is high, and the dielectric breakdown position can be detected after receiving the dielectric breakdown accident without receiving electromagnetic interference. can do. (B) By comparing the signals from each insulation connection portion 2, it becomes possible to detect the insulation breakdown position with high accuracy even in the long distance cable line 1. (C) Since the surge energy generated in each insulation connection part 2 is detected and the detection signal is sent to the centralized monitoring station 5, the detection signals from each insulation connection part 2 can be collectively monitored. . (D) Degaussing circuit 34 for degaussing the magnetized steel piece 33a that has been magnetized
Therefore, even if the magnetic steel piece 33a is magnetized at the adjustment stage of the set or for some other reason, the intensity of each optical signal is recorded after a dielectric breakdown accident, and the offset is removed by resetting. Measurement accuracy can be improved. (E) Since the high frequency component with large propagation attenuation is used, the detection position accuracy can be improved.

In the first embodiment, the metal foil electrode 2 is used.
Although the method of taking surge energy from c has been described, other surge pulse detection methods used in the partial discharge detection technique can be applied. FIG. 3 schematically shows a dielectric breakdown position detection system according to the second embodiment to which this surge pulse detection method is applied. This system is obtained by adding a partial discharge detection circuit 7 to the system shown in FIG. This partial discharge detection circuit 7
Is to detect the partial discharge of the insulating connection portion 2 by inputting the potential difference between both ends of the partial discharge detection impedance 6.
The partial discharge detection impedance 6 is connected to the metal foil electrode 2c of the insulating connection portion 2 and is configured to detect the potential thereof.

The partial discharge detected by the partial discharge detection circuit 7 is converted into an optical signal by the light emitting diode 8 and transmitted to the centralized monitoring station 5 by the optical fiber cable 4 together with the optical signal output by the light emitting diode 36. Even if the centralized monitoring station 5 does not detect the dielectric breakdown position, it can detect the deterioration of the insulators of the plurality of insulating connection portions 2 ₁ , 2 ₂ , ... 2 _n and prevent the dielectric breakdown from occurring. Cost reduction can be achieved by using the signal transmission system of the partial discharge measurement system and the dielectric breakdown position detection system together.

The present invention is not limited to the above embodiment, and various embodiments are possible. For example, in the above-described embodiment, the case where the generated surge energy is converted into magnetic energy and held in the magnetic steel piece 33a and the held magnetism is detected by the magnetoresistive effect element 35 has been described. As a method of recording by some method and detecting the recording result later, for example, the following can be used. (1) Charging method A unipolar surge voltage is charged into an electrostatic capacitor, and the DC voltage is detected using the peak hold circuit, Pockels effect, or Kerr effect to determine the magnitude of surge energy. (2) Electrochemical action A unipolar surge voltage is applied to the electrolytic solution to cause electrolysis, and the amount of electrolysis is detected to determine the magnitude of surge energy. (3) Mechanical displacement A unipolar surge is energized to the coil and its electromagnetic force causes mechanical displacement, for example, elongation of a leaf spring, and the displacement is measured later as a mechanism to hold the maximum displacement and the magnitude of surge energy is increased. Ask for Also, the magnitude of the surge energy is obtained by the photoelastic effect. (4) The amount of magnetization recorded on magnetic steel strips or magnetic tapes is detected by the Hall effect element and Faraday effect element. (5) Change the surge energy into a thermal change and detect the amount of the thermal change later. In addition, there are two types of insulation connections, one that can detect surge energy and one that cannot detect surge energy as in the above-mentioned embodiment. , Positioning technology for measuring partial discharge (Totani, Endo, and 2 others: “Development of high-sensitivity detection technology for partial discharge of power cable lines”) The Institute of Electrical Engineers of Japan, Wire / Cable Research Group
It is effective to use EC-94-21).

[0024]

As described above, according to the present invention, the surge electric energy detected between the two sheaths of the insulated connection is held and then read out. Therefore, the structure is simple, the reliability is high, and the dielectric breakdown occurs. It is possible to detect the dielectric breakdown position after an accident occurs. Also, by using the high-frequency component with large propagation attenuation and comparing the surge electric energy from each insulation connection part, it becomes possible to detect the insulation breakdown position with high accuracy even in a long-distance cable line. .

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an outline of a system for detecting insulation breakdown position of a cable line according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram showing details of a dielectric breakdown detection circuit according to the first embodiment of the present invention.

FIG. 3 is a configuration diagram showing an outline of a dielectric breakdown position detecting system for a cable line according to a second embodiment of the present invention.

[Explanation of symbols]

1 long-distance cable track 2 insulated connection 2a insulation tube 2b sheath 2c Metal foil electrode 2d lead wire 3 Dielectric breakdown detection circuit 30 band pass filter (BPF) 30a capacitor 30b high frequency coil 31 Double-wave detector (rectifier) 32 integrating circuit 33 Magnetic hold part 33a Magnetic steel piece 33b York 33c Excitation coil 34 Degaussing circuit 34a Degaussing coil 34b drive circuit 35 Magnetoresistive effect element 36 light emitting diode 37 DC power supply 37 4 optical fiber cable 5 Central monitoring stations 50 photodiodes 51 Surge energy intensity display 52 DC power supply 6 Partial discharge detection impedance 7 Partial discharge detection circuit 8 light emitting diodes

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Kenichiro Soma, Inventor Kenichiro So, 5-1-1 Hidaka-cho, Hitachi, Ibaraki Prefecture, Power Systems Research Laboratories, Nitrate Electric Cable Co., Ltd. 5th-1st No. 1 in the Power System Laboratory, Nittsu Electric Cable Co., Ltd. (56) Reference JP-A-62-161078 (JP, A) JP-A-6-331691 (JP, A) JP-A-2-210277 (JP , A) Actual Kaihei 4-59483 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) G01R 31/08-31/14

Claims (12)

(57) [Claims] 1. A long-distance cable line connected by a plurality of insulating connecting portions, wherein the plurality of insulating connecting portions are provided outside the sheath on both sides of the insulating cylinder.
Provided was detected Rusa over di of electrical energy generated from the metal foil electrodes when the dielectric breakdown, converted from previous hexa over di of electrical energy by extracting the high-frequency surge of electrical energy to the unipolar pulsed current, the single save the polarity pulse current to each of the plurality of insulating the connecting portion
Recorded and converted into energy available, the plurality of insulating connecting portions each read the recorded energy <br/> and out, the insulating contact based on the intensity of the read energy
A method for detecting the position of insulation breakdown in a cable line that detects whether insulation breakdown has occurred at the connection . 2. A surge of electrical energy <br/> formic over the frequency for the extraction JP to be a frequency in the range of 1~50MHz
The method for detecting a dielectric breakdown position of a cable line according to claim 1, which is a characteristic of the method. Wherein the storable energy, the insulation breakdown position detection method of claim 1, wherein the cable line, which is a magnetic energy. 4. A before Ki磁 care energy, came to a hard ferromagnetic
Breakdown position detection method according to claim 3, wherein the cable line, characterized in that that will be recorded. 5. The magnetic energy is a magnetoresistive effect element.
The cable according to claim 3, which is recorded in
Detection method for dielectric breakdown position of line. 6. The magnetic energy is magnetized to a magnetic steel piece.
The method for detecting a dielectric breakdown position of a cable line according to claim 3 , wherein the method is followed by degaussing by a degaussing circuit . Wherein said storable energy, the capacitor
The method for detecting a dielectric breakdown position of a cable line according to claim 1 , characterized in that the electrostatic energy is recorded in ( 1). Wherein said storable energy is serial in the electrolyte
The method for detecting a dielectric breakdown position of a cable line according to claim 1 , characterized in that it is recorded electrochemical energy. Wherein said storable energy is mechanical displacement
And characterized in that the mechanical energy to be recorded in the form of
The method for detecting a dielectric breakdown position of a cable line according to claim 1. Wherein said storable energy is thermal change
Characterized by being thermal energy recorded in the form of quantity
The method for detecting a dielectric breakdown position of a cable line according to claim 1. 11. The aboveRecordedOf energyreading
Is the pluralRecorded for each insulated connectionEnergy
Convert to optical signal,The aboveOptical signal through fiber optic cable
do itAt a common central monitoring stationReceive lightStructureSuccessHaveClaim 1
A method for detecting the dielectric breakdown position of the cable line described. 12. A plurality of insulating connecting portions are connected to each other, and the plurality of insulating connecting portions are provided outside the sheath on both sides of the insulating cylinder.
The partial discharge energy is detected from the electrode of the metal foil,
Converting partial discharge energy into first light energy,
The first light energy is shared by the optical fiber cable.
In long-distance cable line for transmitting to the centralized monitoring stations through, the metal foil electrodes from detected a salicylate over di of electrical energy generated at the time of dielectric breakdown, the previous high-frequency surge of electrical energy from the hexa over di of electrical energy Extract and convert to unipolar pulse current, and store the unipolar pulse current for each of the plurality of insulation connections
Record the energy by converting it into a possible energy, and record the energy for each of the plurality of insulated connections.
Read and converted to a second optical energy, before Symbol a second optical energy transmitted by the optical fiber cable to said common central monitoring office, said first light energy at said common central monitoring stations
Detects partial discharge at the insulation connection based on
The insulation connection based on the intensity of the second light energy
A method for detecting the position of a cable dielectric breakdown characterized by detecting whether or not a dielectric breakdown has occurred at the section .