JP3317391B2 - Method and apparatus for diagnosing insulation deterioration of a live power cable - Google Patents
Method and apparatus for diagnosing insulation deterioration of a live power cableInfo
- Publication number
- JP3317391B2 JP3317391B2 JP03910197A JP3910197A JP3317391B2 JP 3317391 B2 JP3317391 B2 JP 3317391B2 JP 03910197 A JP03910197 A JP 03910197A JP 3910197 A JP3910197 A JP 3910197A JP 3317391 B2 JP3317391 B2 JP 3317391B2
- Authority
- JP
- Japan
- Prior art keywords
- current
- power cable
- voltage
- measured
- frequency
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 238000009413 insulation Methods 0.000 title claims description 92
- 230000006866 deterioration Effects 0.000 title claims description 80
- 238000000034 method Methods 0.000 title claims description 32
- 238000003745 diagnosis Methods 0.000 claims description 28
- 230000015556 catabolic process Effects 0.000 claims description 10
- 238000006731 degradation reaction Methods 0.000 claims description 8
- 238000005259 measurement Methods 0.000 claims description 5
- 241000287462 Phalacrocorax carbo Species 0.000 claims 1
- 240000005572 Syzygium cordatum Species 0.000 description 13
- 235000006650 Syzygium cordatum Nutrition 0.000 description 13
- 230000000694 effects Effects 0.000 description 8
- 239000011810 insulating material Substances 0.000 description 6
- 239000012212 insulator Substances 0.000 description 6
- 238000004804 winding Methods 0.000 description 5
- 238000012935 Averaging Methods 0.000 description 2
- 239000003990 capacitor Substances 0.000 description 2
- 229920003020 cross-linked polyethylene Polymers 0.000 description 2
- 239000004703 cross-linked polyethylene Substances 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- 230000007423 decrease Effects 0.000 description 1
- 230000020169 heat generation Effects 0.000 description 1
- 230000007935 neutral effect Effects 0.000 description 1
- 230000000737 periodic effect Effects 0.000 description 1
- 239000002861 polymer material Substances 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 238000007619 statistical method Methods 0.000 description 1
Landscapes
- Testing Of Short-Circuits, Discontinuities, Leakage, Or Incorrect Line Connections (AREA)
- Measurement Of Resistance Or Impedance (AREA)
Description
【０００１】[0001]
【発明の属する技術分野】本発明は活線電力ケーブルの
絶縁劣化診断方法及び装置に係り、より詳細には、運転
状態にある活線下の電力ケーブル、例えばＣＶケーブル
と称される架橋ポリエチレン絶縁電力ケーブルの絶縁劣
化を診断する方法及び装置に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for diagnosing insulation deterioration of a live power cable, and more particularly to a power cable under a live line in an operating state, for example, a cross-linked polyethylene insulation called CV cable. The present invention relates to a method and an apparatus for diagnosing insulation deterioration of a power cable.
【０００２】[0002]
【従来の技術】絶縁材料、特に高分子材料は、使用中に
種々の原因により、次第にその絶縁性能が低下する、所
謂絶縁劣化現象が生じる。絶縁材料の劣化は使用される
絶縁材料の種類、使用される場所によって劣化の状態が
異なる。この絶縁材料の劣化の状態を知ることは、電力
ケーブルの絶縁破壊事故を予防する上で極めて重要であ
る。2. Description of the Related Art Insulating materials, particularly polymer materials, have a so-called insulation deterioration phenomenon in which their insulating performance gradually decreases due to various causes during use. Deterioration of the insulating material differs depending on the type of the insulating material used and the place where the insulating material is used. It is extremely important to know the state of deterioration of the insulating material in order to prevent a power cable dielectric breakdown accident.
【０００３】架橋ポリエチレンを絶縁材料とするＣＶケ
ーブルの絶縁劣化は、主に水トリーによることが知られ
ている。従って、ＣＶケーブルの絶縁劣化による絶縁破
壊事故を未然に防ぐには、この水トリーの発生を知るこ
とが重要である。そこで、従来より、布設された電力ケ
ーブルの水トリーを活線下で直流電流成分を検出するこ
とによって検知する方法が開発されている。It is known that the insulation deterioration of CV cables using crosslinked polyethylene as an insulating material is mainly caused by water trees. Therefore, it is important to know the occurrence of this water tree in order to prevent an insulation breakdown accident due to insulation deterioration of the CV cable. Therefore, conventionally, a method of detecting a water tree of a laid power cable by detecting a direct current component under a live line has been developed.
【０００４】しかし、この方法では、大地からケーブル
のシース絶縁抵抗を介して流れる迷走電流の影響を受け
易く、精度のよい測定ができない。このため、直流電圧
を重畳し、劣化信号を大きくする方法が検討されてい
る。直流電圧を重畳する方法には２つの方法があり、そ
の１つは例えば特開昭５９−２０２０７８号公報に示さ
れているようにリアクトル或いは接地用変圧器（ＧＰ
Ｔ）の中性点から重畳する方法であり、他の１つは例え
ば特開昭６３−１３９２６１号公報に示されているよう
に電力ケーブルの遮へい層から重畳する方法である。However, this method is susceptible to stray current flowing from the ground via the sheath insulation resistance of the cable, and cannot perform accurate measurement. For this reason, a method of superimposing a DC voltage to increase the deterioration signal has been studied. There are two methods for superimposing a DC voltage, one of which is a reactor or a grounding transformer (GP) as disclosed in, for example, JP-A-59-202078.
T) A method of superimposing from a neutral point, and the other is a method of superimposing from a shielding layer of a power cable as shown in, for example, JP-A-63-139261.
【０００５】[0005]
【発明が解決しようとする課題】しかし、前者の方法で
は、リアクトルを接続するために高圧活線作業を行う必
要があったり、ＧＰＴが種々の理由によって使えない場
合もある。更に、並列に接続されているＧＰＴに直流電
流が環流し、磁気飽和や発熱の原因になる。一方、後者
の方法では、直流電圧の重畳によってシース絶縁抵抗を
介して流れる直流電流が水トリーからの劣化信号に重畳
してしまい、その分離は極めて困難な状況となってい
た。However, in the former method, there is a case where it is necessary to perform a high-voltage live-line operation for connecting the reactor, or the GPT cannot be used for various reasons. Furthermore, direct current circulates through the GPTs connected in parallel, causing magnetic saturation and heat generation. On the other hand, in the latter method, the direct current flowing through the sheath insulation resistor is superimposed on the deterioration signal from the water tree due to the superposition of the DC voltage, and the separation is extremely difficult.
【０００６】よって本発明は、上述した従来の問題点に
鑑み、水トリーによる真の劣化信号を検出し、精度の高
い診断を行うことのできる活線電力ケーブルの絶縁劣化
診断方法及び装置を提供することを課題としている。Accordingly, the present invention has been made in view of the above-described conventional problems, and provides a method and an apparatus for detecting insulation deterioration of a live power cable, which can detect a true deterioration signal caused by a water tree and perform a highly accurate diagnosis. The challenge is to do.
【０００７】[0007]
【課題を解決するための手段】上記課題を解決するため
本発明により成された請求項１記載の活線電力ケーブル
の絶縁劣化診断方法は、活線下で測定対象とする電力ケ
ーブルの遮へい層に交流電源によって商用周波数の整数
倍±ａＨｚ（０＜ａ≦１０）の周波数の交流電圧を印加
し、前記電力ケーブルから前記交流電源を介して接地に
流れる電流を電流測定手段により測定し、該電流測定手
段により測定した電流に基づいて前記電力ケーブルの絶
縁劣化の程度を活線状態で診断することを特徴としてい
る。According to the present invention, there is provided a method for diagnosing deterioration of insulation of a live power cable in accordance with the present invention. An AC voltage having a frequency of an integral multiple of the commercial frequency ± aHz (0 <a ≦ 10) is applied by an AC power supply to the AC power supply, and a current flowing from the power cable to the ground via the AC power supply is measured by current measuring means. Current measuring hand
The degree of insulation deterioration of the power cable is diagnosed in a live state based on the current measured by the step .
【０００８】上記方法において、電力ケーブルの遮へい
層に商用周波数の整数倍±ａＨｚ（０＜ａ≦１０）の周
波数の交流電圧を印加すると、略ａＨｚの電圧を重畳し
たり、略ａＨｚで印加電圧を変化させたと同じような効
果があり、電力ケーブルに絶縁劣化があれば、電力ケー
ブルから交流電源を介して接地に絶縁劣化の程度に応じ
た大きさの電流が流れるので、電流測定手段により測定
した電力ケーブルから交流電源を介して接地に流れる電
流に基づいて診断手段が電力ケーブルの絶縁劣化の程度
を活線状態で診断することができる。In the above method, when an AC voltage having a frequency of an integral multiple of the commercial frequency ± a Hz (0 <a ≦ 10) is applied to the shielding layer of the power cable, a voltage of approximately a Hz is superimposed or the applied voltage is approximately a Hz. has the same effect as changing the, if any insulation deterioration in power cables, since the magnitude of the current corresponding to the degree of insulation deterioration to ground via an AC power from the power cable, measured by the current measuring means The diagnostic means can diagnose the degree of insulation deterioration of the power cable in a live state based on the current flowing from the power cable to the ground via the AC power supply .
【０００９】請求項２記載の活線電力ケーブルの絶縁劣
化診断方法は、前記電流測定手段により測定する電流が
略ａＨｚの電流成分であり、前記診断手段が前記略ａＨ
ｚの電流成分の大きさにより前記診断を行うことを特徴
としている。[0009] insulation degradation diagnosis method of live-line electric power cable according to claim 2 is the current component of the current substantially aHz be measured by the current measuring means, said diagnosis means the generally aH
The diagnosis is performed based on the magnitude of the current component of z.
【００１０】上記方法において、電力ケーブルから交流
電源を介して接地に流れる絶縁劣化の程度に応じた大き
さの電流が略ａＨｚの周期で変化することに着目し、電
力ケーブルから交流電源を介して接地に流れる略ａＨｚ
の電流成分を電流測定手段により測定しているので、こ
の測定した略ａＨｚの電流成分の大きさにより診断手段
が電力ケーブルの絶縁劣化の程度を活線状態で診断する
ことができる。[0010] In the above method, the AC power is supplied from the power cable.
Through the power Noting that current having a magnitude corresponding to the degree of insulation deterioration which flows to the ground varies with a period of approximately a Hz, electrostatic
Approximately aHz flowing from power cable to ground via AC power supply
Since the current component is measured by the current measuring means, the diagnostic means according to the size of the current component of the measured substantially aHz
There can be diagnosed degree of insulation deterioration of a power cable in a hot line state.
【００１１】請求項３記載の活線電力ケーブルの絶縁劣
化診断方法は、前記電流測定手段により測定した電流が
直流電流成分であり、前記診断手段が前記交流電圧印加
時の前記直流電流成分の平均値と前記交流電圧印加前の
直流電流成分の平均値との差により前記診断を行うこと
を特徴としている。[0011] insulation degradation diagnosis method of live-line electric power cable according to claim 3 is the direct current component current is measured by the current measuring means, average the diagnostic means of the direct current component at the time of the AC voltage applied The diagnosis is performed based on a difference between the value and the average value of the DC current component before the AC voltage is applied.
【００１２】上記方法において、電力ケーブルの遮へい
層に商用周波数の奇数倍±ａＨｚ（０＜ａ≦１０）の周
波数の交流電圧を印加すると、電力ケーブルに絶縁劣化
があれば、電力ケーブルから交流電源を介して接地に絶
縁劣化の程度に応じた大きさの直流電流成分が流れ、電
流測定手段により測定した電力ケーブルから交流電源を
介して接地に流れる直流電流成分の平均値と交流電圧印
加前の平均値との差を診断手段がとっているので、この
差の大きさにより電力ケーブルの絶縁劣化の程度を活線
状態で診断することができる。In the above method, when an AC voltage having a frequency of an odd multiple of the commercial frequency ± aHz (0 <a ≦ 10) is applied to the shielding layer of the power cable, if the insulation of the power cable is deteriorated, the AC power is supplied from the power cable. a direct current component having a magnitude corresponding to the degree of insulation deterioration ground flows through, electrostatic
AC power from the power cable measured by the
Diagnosis means takes the difference between the average value of the DC current component flowing to the ground and the average value before the AC voltage is applied, and diagnoses the degree of insulation deterioration of the power cable in the live state based on the magnitude of this difference. can do.
【００１３】上記課題を解決するため本発明により成さ
れた請求項４記載の活線電力ケーブルの絶縁劣化診断方
法は、活線下で測定対象とする電力ケーブルの遮へい層
に交流電源によって商用周波数の整数（２以上）分の１
倍±ａＨｚ（０＜ａ≦１０）の周波数の交流電圧を印加
し、前記電力ケーブルから前記交流電源を介して接地に
流れる電流を電流測定手段により測定し、該電流測定手
段により測定した電流に基づいて前記診断手段が前記電
力ケーブルの絶縁劣化の程度を活線状態で診断し、前記
電流測定手段により測定する電流が、前記印加した交流
電圧の周波数及び前記整数の積と前記商用周波数との差
の絶対値に略等しい周波数の電流成分であり、前記診断
手段が該電流成分の大きさにより前記診断を行うことを
特徴としている。According to a fourth aspect of the present invention, there is provided a method for diagnosing deterioration of insulation of a live power cable in accordance with the present invention. 1 / integer (2 or more)
An AC voltage of a frequency doubler ± aHz (0 <a ≦ 10 ) is applied, as measured by the current measuring means a current flowing to ground through the AC power from the power cable, the current measurement hand
The diagnostic means diagnoses the degree of insulation deterioration of the power cable in a live state based on the current measured by the step ,
The current measured by the current measuring means is the applied AC
The difference between the product of the frequency of the voltage and the integer and the commercial frequency
Current component having a frequency substantially equal to the absolute value of
The means performs the diagnosis based on the magnitude of the current component .
【００１４】上記方法において、電力ケーブルの遮へい
層に商用周波数の整数（２以上）分の１倍±ａＨｚ（０
＜ａ≦１０）の周波数の交流電圧を印加すると、略整数
倍×ａＨｚで印加電圧を変化したり略整数倍×ａＨｚの
電圧を重畳したと同じようになり、電力ケーブルに絶縁
劣化があれば、電力ケーブルから交流電源を介して接地
に、印加した交流電圧の周波数及び整数の積と商用周波
数との差の絶対値に略等しい周波数の電流成分の大きさ
が絶縁劣化の程度に応じた大きさとなる電流が流れるの
で、電流測定手段により測定した電力ケーブルから交流
電源を介して接地に流れる電流に基づいて診断手段が電
力ケーブルの絶縁劣化の程度を活線状態で診断すること
ができる。[0014] In the above method, the shielding layer of the power cable may have an integral (2 or more) times the commercial frequency ± a Hz (0 Hz).
When an AC voltage having a frequency of <a ≦ 10) is applied, the applied voltage is changed at a substantially integer times × aHz, or the voltage is superimposed on a substantially integer times × aHz. And the commercial frequency with the product of the frequency and the integer of the applied AC voltage from the power cable to the ground via the AC power supply.
The magnitude of the current component at a frequency approximately equal to the absolute value of the difference from the number
There because current flows as a magnitude corresponding to the degree of insulation deterioration, AC from a power cable was measured by the current measuring means
Based on the current flowing to the ground via the power supply, the diagnosis means can diagnose the degree of insulation deterioration of the power cable in a live state.
【００１５】請求項５記載の活線電力ケーブルの絶縁劣
化診断装置は、活線下で測定対象とする電力ケーブルの
遮へい層と接地間に接続された接地線の途中に設けら
れ、前記遮へい層に商用周波数の整数倍±ａＨｚ（０＜
ａ≦１０）の周波数の交流電圧を印加する交流電源と、
前記電力ケーブルから前記交流電源及び前記接地線を介
して接地に流れる電流を測定する電流測定手段と、該電
流測定手段により測定した電流に基づいて前記電力ケー
ブルの絶縁劣化の程度を活線状態で診断する診断手段と
を備えることを特徴としている。According to a fifth aspect of the present invention, there is provided an apparatus for diagnosing deterioration of insulation of a live power cable, which is provided in the middle of a ground line connected between a shield layer and a ground of a power cable to be measured under the live line, and wherein the shield layer is provided. Is an integral multiple of the commercial frequency ± aHz (0 <
a ≦ 10) an AC power supply for applying an AC voltage having a frequency of
Current measuring means for measuring a current flowing from the power cable to the ground via the AC power supply and the ground wire, and a degree of insulation deterioration of the power cable in a live state based on the current measured by the current measuring means. Diagnostic means for diagnosing.
【００１６】上記構成において、活線下で測定対象とす
る電力ケーブルの遮へい層と接地間に接続された接地線
の途中に設けられた交流電源が、遮へい層に商用周波数
の整数倍±ａＨｚ（０＜ａ≦１０）の周波数の交流電圧
を印加すると、略ａＨｚで印加電圧を変化したり略ａＨ
ｚの電圧を重畳したと同じような効果がある。従って、
電力ケーブルに絶縁劣化があれば、電力ケーブルから接
地に絶縁劣化の程度に応じた大きさの電流が流れ、この
電流が電流測定手段により測定され、この測定した電流
に基づいて診断手段により電力ケーブルの絶縁劣化の程
度が活線状態で診断されるようになる。In the above configuration, an AC power supply provided in the middle of a ground line connected between the shield layer and the ground of the power cable to be measured under the live line is provided with an integral multiple of the commercial frequency ± aHz ( When an AC voltage having a frequency of 0 <a ≦ 10) is applied, the applied voltage changes at approximately aHz or approximately aH
The same effect as when the voltage of z is superimposed is obtained. Therefore,
If the power cable has insulation deterioration, a current of a magnitude corresponding to the degree of insulation deterioration flows from the power cable to the ground, and this current is measured by the current measuring means, and based on the measured current, the power cable is diagnosed by the diagnostic means. The degree of insulation deterioration is diagnosed in a live state.
【００１７】請求項６記載の活線電力ケーブルの絶縁劣
化診断装置は、前記電流測定手段が略ａＨｚの電流成分
を測定し、前記診断手段が前記略ａＨｚの電流成分の大
きさにより診断を行うことを特徴としている。According to a sixth aspect of the present invention, in the apparatus for diagnosing deterioration of insulation of a live power cable, the current measuring means measures a current component of about a Hz, and the diagnosis means makes a diagnosis based on the magnitude of the current component of about a Hz. It is characterized by:
【００１８】上記構成において、電力ケーブルから接地
に流れる絶縁劣化の程度に応じた大きさの電流が略ａＨ
ｚの周期で変化することに着目し、電流測定手段がこの
略ａＨｚの電流成分を測定しているので、診断手段がこ
の測定した略ａＨｚの電流成分の大きさにより電力ケー
ブルの絶縁劣化の程度を活線状態で診断することができ
る。In the above configuration, a current having a magnitude corresponding to the degree of insulation deterioration flowing from the power cable to the ground is substantially aH.
Paying attention to the fact that the current component changes with the cycle of z, the current measuring means measures the current component of approximately a Hz, so the diagnostic means determines the degree of insulation deterioration of the power cable according to the magnitude of the measured current component of approximately a Hz. Can be diagnosed in a live state.
【００１９】請求項７記載の活線電力ケーブルの絶縁劣
化診断装置は、前記電流測定手段が直流電流成分を測定
し、前記診断手段が前記交流電圧印加時の前記直流電流
成分の平均値と前記交流電圧印加前の直流電流成分の平
均値との差により診断を行うことを特徴としている。According to a seventh aspect of the present invention, in the apparatus for diagnosing insulation deterioration of a live power cable, the current measuring means measures a direct current component, and the diagnosing means measures an average value of the direct current component when the alternating voltage is applied and the average value of the direct current component. Diagnosis is performed based on a difference from the average value of the DC current component before the application of the AC voltage.
【００２０】上記構成において、交流電源が電力ケーブ
ルの遮へい層に商用周波数の整数倍±ａＨｚ（０＜ａ≦
１０）の周波数の交流電圧を印加すると、電力ケーブル
に絶縁劣化があれば、電力ケーブルから接地に略ａＨｚ
で変化する絶縁劣化の程度に応じた大きさの直流電流成
分が流れ、電流測定手段が測定した直流電流成分の平均
値と交流電圧印加前の平均値との差をとっているので、
この差の大きさにより電力ケーブルの絶縁劣化の程度を
活線状態で診断することができる。In the above configuration, the AC power supply is provided at the shielding layer of the power cable at an integral multiple of the commercial frequency ± a Hz (0 <a ≦
When an AC voltage having a frequency of 10) is applied, if there is insulation deterioration in the power cable, the power cable is connected to the ground at approximately aHz.
Since the DC current component having a magnitude corresponding to the degree of insulation deterioration that changes in the above flows, and the difference between the average value of the DC current component measured by the current measuring means and the average value before the AC voltage is applied,
From the magnitude of this difference, the degree of insulation deterioration of the power cable can be diagnosed in a live state.
【００２１】請求項８記載の活線電力ケーブルの絶縁劣
化診断装置は、活線下で測定対象とする電力ケーブルの
遮へい層と接地間に接続された接地線の途中に設けら
れ、前記遮へい層に商用周波数の整数（２以上）分の１
倍±ａＨｚ（０＜ａ≦１０）の周波数の交流電圧を印加
する交流電源と、前記電力ケーブルから前記交流電源及
び前記接地線を介して接地に流れる電流を測定する電流
測定手段と、該電流測定手段により測定した電流に基づ
いて前記電力ケーブルの絶縁劣化の程度を活線状態で診
断する診断手段とを備え、前記電流測定手段により測定
する電流が、前記印加した交流電圧の周波数及び前記整
数の積と前記商用周波数との差の絶対値に略等しい周波
数の電流成分であり、前記診断手段が該電流成分の大き
さにより前記診断を行うことを特徴としている。According to a eighth aspect of the present invention, there is provided an apparatus for diagnosing deterioration of insulation of a live power cable, which is provided in the middle of a ground line connected between a shield layer and a ground of a power cable to be measured under the live line, and wherein the shield layer is provided. To 1 / integer (2 or more) of commercial frequency
An AC power supply for applying an AC voltage having a frequency of ± aHz (0 <a ≦ 10); current measuring means for measuring a current flowing from the power cable to the ground via the AC power supply and the ground wire; Diagnosing means for diagnosing the degree of insulation deterioration of the power cable in a live state based on the current measured by the measuring means, and measuring by the current measuring means.
Current to be applied depends on the frequency of the applied AC voltage and the
A frequency substantially equal to the absolute value of the difference between the product of numbers and the commercial frequency
Number of current components, and the diagnostic means determines the magnitude of the current components.
Thus, the diagnosis is performed .
【００２２】上記構成において、活線下で測定対象とす
る電力ケーブルの遮へい層と接地間に接続された接地線
の途中に設けられた交流電源が、遮へい層に商用周波数
の整数（２以上）分の１倍±ａＨｚ（０＜ａ≦１０）の
周波数の交流電圧を印加すると、略整数倍×ａＨｚで印
加電圧を変化したり略整数倍×ａＨｚの電圧を重畳した
と同じようになる。従って、電流測定手段により測定す
る電流を、印加した交流電圧の周波数及び整数の積と商
用周波数との差の絶対値に略等しい周波数の電流成分と
することで、電力ケーブルに絶縁劣化があれば、電力ケ
ーブルから接地に絶縁劣化の程度に応じた大きさの電流
が流れ、この電流が電流測定手段により測定され、この
測定した電流に基づいて診断手段により電力ケーブルの
絶縁劣化の程度が活線状態で診断されるようになる。In the above configuration, the AC power supply provided in the middle of the ground wire connected between the shield layer and the ground of the power cable to be measured under the live line has an integer (2 or more) of the commercial frequency in the shield layer. When an AC voltage having a frequency of 1 / ± aHz (0 <a ≦ 10) is applied, the applied voltage is changed at substantially integer times × aHz, or the same as when a voltage of approximately integer times × aHz is superimposed. Therefore, measurement by the current measuring means
Current and the product of the frequency and the integer of the applied AC voltage
Current component at a frequency approximately equal to the absolute value of the difference from the
By doing so, if insulation deterioration occurs in the power cable, a current of a magnitude corresponding to the degree of insulation deterioration flows from the power cable to the ground, and this current is measured by current measuring means, and diagnosis is performed based on the measured current. By this means, the degree of insulation deterioration of the power cable is diagnosed in a live state.
【００２３】[0023]
【発明の実施の形態】以下、本発明の実施の形態を図面
に基づいて説明する。図１は本発明による活線電力ケー
ブルの絶縁劣化診断方法を実施するのに使用する装置の
概略構成を示す図である。同図において、高電圧母線１
にケーブル端末２を介して接続されていて活線下で測定
対象となっている電力ケーブル３には、通常その遮へい
層３ａと接地間に接地線４が接続されている。接地線４
の途中には、遮へい層３ａに商用周波数の整数倍±ａＨ
ｚ（０＜ａ≦１０）の周波数の交流電圧を印加するため
の交流電源５が設けられている。Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a schematic configuration of an apparatus used to carry out a method for diagnosing insulation deterioration of a live power cable according to the present invention. In the figure, high voltage bus 1
The power cable 3, which is connected to the power cable 3 via a cable terminal 2 and is to be measured under a live line, is usually connected with a ground wire 4 between its shielding layer 3a and ground. Ground wire 4
On the way, an integer multiple of the commercial frequency ± aH is applied to the shielding layer 3a.
An AC power supply 5 for applying an AC voltage having a frequency of z (0 <a ≦ 10) is provided.
【００２４】交流電源５は、所定の周波数の交流電圧を
発生する交流電圧発生回路５ａと、この交流電圧発生回
路５ａの出力が接続される一次巻線Ｌ１と接地線２の途
中に挿入された二次巻線Ｌ２とを有し、交流電圧発生回
路５ａが発生する交流電圧を昇圧して接地線４に供給す
る変圧器５ｂとを有する。変圧器５ｂの二次巻線Ｌ２の
一端と接地との間には、電力ケーブル３から変圧器５ｂ
の二次巻線Ｌ２及び接地線４を介して接地に流れる電流
を測定する電流測定装置６が接続されている。The AC power supply 5 is inserted in the middle of a grounding wire 2 and an AC voltage generating circuit 5a for generating an AC voltage of a predetermined frequency, and a primary winding L1 to which an output of the AC voltage generating circuit 5a is connected. And a transformer 5b having a secondary winding L2 and boosting the AC voltage generated by the AC voltage generating circuit 5a and supplying the boosted AC voltage to the ground line 4. Between one end of the secondary winding L2 of the transformer 5b and the ground, the power cable 3 connects the transformer 5b
A current measuring device 6 for measuring a current flowing to the ground via the secondary winding L2 and the ground wire 4 is connected.
【００２５】また、電流測定装置６には、この電流測定
装置によって測定した電流により電力ケーブルの絶縁劣
化の程度を診断する診断装置７が接続されている。更
に、変圧器５ｂの二次巻線Ｌ２と電流測定装置６とに並
列にこれらを保護するための保安装置８が接続されてい
る。Further, a diagnostic device 7 for diagnosing the degree of insulation deterioration of the power cable based on the current measured by the current measuring device 6 is connected to the current measuring device 6. Further, a security device 8 for protecting the secondary winding L2 of the transformer 5b and the current measuring device 6 is connected in parallel.
【００２６】今、一実施の形態として、交流電源５の交
流電圧発生回路５ａが商用周波数の２倍＋ａＨｚの例え
ば１２１.4Ｈｚの交流電圧を発生している場合について
説明する。Now, as an embodiment, a case will be described in which the AC voltage generating circuit 5a of the AC power supply 5 generates an AC voltage of twice the commercial frequency + aHz, for example, 121.4 Hz.
【００２７】図１に示した回路において、交流電圧発生
回路５ａの発生する交流電圧が変圧器５ｂによって、数
百Ｖ以下の例えば４００Ｖに昇圧されて遮へい層３ａに
印加されると、Ａ〜Ｂ間の電位差、すなわち、供試ケー
ブルである電力ケーブル３の絶縁体に加わっている電圧
Ｖは図２（ａ）及び（ｂ）に示すようになる。なお、
（ａ）においては縦軸の１目盛りは２ｋＶ、横軸の１目
盛りは５ｍｓであり、（ｂ）においては横軸の１目盛り
は0.５ｓである。In the circuit shown in FIG. 1, when the AC voltage generated by the AC voltage generating circuit 5a is boosted to several hundreds V or less, for example, 400V by the transformer 5b and applied to the shielding layer 3a, A to B The potential difference between them, that is, the voltage V applied to the insulator of the power cable 3 which is the test cable is as shown in FIGS. 2 (a) and 2 (b). In addition,
In (a), one scale on the vertical axis is 2 kV, and one scale on the horizontal axis is 5 ms. In (b), one scale on the horizontal axis is 0.5 s.
【００２８】電力ケーブル３の絶縁体に加わっている電
圧Ｖは、近似的には、下式で示される。 Ｖ＝Ｖ´sinω1ｔ−Ｖsinω2ｔ ただし、ω1＝２πｆ1、ω2＝２πｆ2、ｆ1は商用周波
数、ｆ2はａである。このため、電力ケーブル３には、
ａＨｚ程度と商用周波数の電圧の２つが加わることにな
り、ａＨｚ程度の電圧を重畳したのと同じ効果がある。
そこで、ａＨｚ程度の電流に着目した。The voltage V applied to the insulator of the power cable 3 is approximately expressed by the following equation. V = V'sin ω 1 t−Vsin ω 2 t where ω 1 = 2πf 1 , ω 2 = 2πf 2 , f 1 is the commercial frequency, and f 2 is a. For this reason, the power cable 3
Two voltages of about aHz and a commercial frequency are applied, and the same effect as when a voltage of about aHz is superimposed is obtained.
Therefore, attention was paid to a current of about a Hz.
【００２９】図３（ａ）及び（ｂ）は劣化ケーブル及び
新品ケーブルの何れも三相一括に１２１Ｈｚ、４００Ｖ
の電圧を重畳した結果をグラフでそれぞれ示し、下表１
（ａ）及び（ｂ）は結果を要約して示す。表１中、Ｉdc
は電力ケーブルからの直流成分の測定電流の平均値、Ｉ
dc max は電力ケーブルからの測定電流の最大値、Ｉdc
minは電力ケーブルからの測定電流の最小値、Ｒs は絶
縁体の絶縁抵抗、Ｅsは絶縁体と接地との間の電位差、
Ｉacは電力ケーブルからの充電電流値をそれぞれ示す。FIGS. 3 (a) and 3 (b) show that both the deteriorated cable and the new cable have three phases at a time of 121 Hz and 400V.
The results obtained by superimposing the voltages shown in FIGS.
(A) and (b) summarize the results. In Table 1, Idc
Is the average value of the measured current of the DC component from the power cable, I
dc max is the maximum value of the measured current from the power cable, Idc
min is the minimum value of the measured current from the power cable, Rs is the insulation resistance of the insulator, Es is the potential difference between the insulator and ground,
Iac indicates a charging current value from the power cable.
【００３０】[0030]
【表１】 [Table 1]
【００３１】図３（ａ）から明らかなように、劣化ケー
ブルではａＨｚ程度の周期が明確に現れる。これらのこ
とより、ａＨｚ程度の周期を示す電流の大きさ、特にピ
ーク・ピーク値、すなわち、Ｉdc max 及びＩdc min か
ら電力ケーブルの絶縁劣化の程度を評価できる。As is clear from FIG. 3A, a period of about aHz clearly appears in the deteriorated cable. From these facts, it is possible to evaluate the degree of insulation deterioration of the power cable from the magnitude of the current showing a cycle of about a Hz, particularly the peak-to-peak value, that is, Idc max and Idc min.
【００３２】単相ケーブルでも劣化ケーブルにおけるａ
Ｈｚ程度の電流値から劣化程度を評価できるが、この場
合は充電電流分を除いて考える必要がある。上述のよう
な三相一括では充電電流が相殺されるため、ほとんど考
慮する必要がない。Even in a single-phase cable, a
The degree of deterioration can be evaluated from a current value of about Hz, but in this case, it is necessary to remove the charge current. In the above-described three-phase collective operation, the charging current is canceled out, so that there is almost no need to consider it.
【００３３】また、迷走電流の変動などのノイズ電流分
についてはａＨｚ程度の電流のピーク・ピーク値を平均
化するなどの統計的手法によってこれらを除去すること
が可能になる。更に、本発明の方法では、重畳している
電圧が交流電圧であり、直流電圧のようにシース絶縁抵
抗を介して生じる迷走電流が増大せず、劣化信号だけが
増幅される。In addition, noise components such as fluctuations of stray currents can be removed by a statistical method such as averaging the peak-to-peak values of the current of about aHz. Furthermore, in the method of the present invention, the superimposed voltage is an AC voltage, and the stray current generated via the sheath insulation resistance does not increase unlike the DC voltage, and only the deteriorated signal is amplified.
【００３４】上述した実施の形態によれば、電力ケーブ
ルの遮へい層に商用周波数の２倍＋ａＨｚの交流電圧を
印加しているが、一般的には、商用周波数の偶数倍＋ａ
Ｈｚの交流電圧を印加した場合、ａＨｚ程度の電圧を重
畳したと同じような効果が得られ易く、ａＨｚ程度の電
流の大きさから電力ケーブルの絶縁劣化を診断できる。
また、この交流電圧を印加する前後の直流電流成分の平
均値の差からも電力ケーブルの絶縁劣化を診断できる。
さらに、コンデンサを挿入するなどの手段によって迷走
電流を除去できる他、迷走電流の変動などについては電
流のピーク−ピークの平均化などの統計定期な処理によ
って影響を小さくすることができる。勿論、交流電圧を
重畳しているので、シース絶縁抵抗を介して生じる迷走
電流は極めて小さくなっている。According to the above-described embodiment, an AC voltage of twice the commercial frequency + a Hz is applied to the shielding layer of the power cable. However, in general, an even multiple of the commercial frequency + a
When an AC voltage of Hz is applied, the same effect as when a voltage of about aHz is superimposed is easily obtained, and the insulation deterioration of the power cable can be diagnosed from the magnitude of the current of about aHz.
Also, the insulation deterioration of the power cable can be diagnosed from the difference between the average values of the DC current components before and after the application of the AC voltage.
Furthermore, in addition to removing the stray current by means such as inserting a capacitor, the influence of fluctuation of the stray current can be reduced by statistical periodic processing such as current-peak averaging. Of course, since the AC voltage is superimposed, the stray current generated via the sheath insulation resistance is extremely small.
【００３５】今、他の実施の形態として、交流電源５の
交流電圧発生回路５ａが商用周波数の１倍＋ａＨｚの例
えば６１.4Ｈｚの交流電圧を発生している場合について
説明する。Now, as another embodiment, a case where the AC voltage generating circuit 5a of the AC power supply 5 generates an AC voltage of 11.4 times the commercial frequency + aHz, for example, 61.4 Hz will be described.
【００３６】図１に示した回路において、交流電圧発生
回路５ａの発生する交流電圧が変圧器５ｂによって、数
百Ｖ以下の例えば４００Ｖに昇圧されて遮へい層３ａに
印加されると、Ａ〜Ｂ間の電位差、すなわち、供試ケー
ブルである電力ケーブル３の絶縁体に加わっている電圧
Ｖは図４に示すようになる。なお、同図においては縦軸
の１目盛りは２ｋＶ、横軸の１目盛りは0.５ｓである。In the circuit shown in FIG. 1, when the AC voltage generated by the AC voltage generating circuit 5a is boosted by the transformer 5b to, for example, 400V of several hundred V or less and applied to the shielding layer 3a, AB is applied. The potential difference between them, that is, the voltage V applied to the insulator of the power cable 3 as the test cable is as shown in FIG. In the figure, one scale on the vertical axis is 2 kV, and one scale on the horizontal axis is 0.5 s.
【００３７】電力ケーブル３の絶縁体に加わっている電
圧Ｖは、近似的には、下式で示される。 Ｖ＝（Ｖ´＋α・ω2）sinω1ｔ ただし、ω1＝２πｆ1、ω2＝２πｆ2、αは係数、ｆ1
は商用周波数、ｆ2はａである。このため、電力ケーブ
ル３に加わる電圧はａＨｚ程度で商用周波数の振幅が変
化し、ａＨｚ程度の印加電圧を変化させたと同じような
効果がある。この場合、ａＨｚ程度の電流成分はあまり
明確ではないが、この交流電圧を印加する前後の直流電
流成分の平均値の差からこの電力ケーブル３の絶縁劣化
の程度を評価できる。The voltage V applied to the insulator of the power cable 3 is approximately expressed by the following equation. V = (V ′ + α · ω 2 ) sin ω 1 t where ω 1 = 2πf 1 , ω 2 = 2πf 2 , α is a coefficient, f 1
A commercial frequency, f 2 is a. For this reason, the voltage applied to the power cable 3 changes at about a Hz, the amplitude of the commercial frequency changes, and there is the same effect as changing the applied voltage at about a Hz. In this case, the current component at about aHz is not so clear, but the degree of insulation deterioration of the power cable 3 can be evaluated from the difference between the average values of the DC current components before and after the application of the AC voltage.
【００３８】下表２は劣化ケーブルと新品ケーブルにお
ける交流電圧を印加する前後の直流成分電流値を示す。
同表から両者の判別が容易にできることがわかる。ただ
し、ａ＝1.４Ｈｚ、Ｖ＝８００Ｖである。Table 2 below shows the DC component current values of the deteriorated cable and the new cable before and after the application of the AC voltage.
It can be seen from the table that both can be easily determined. However, a = 1.4 Hz and V = 800 V.
【００３９】[0039]
【表２】 [Table 2]
【００４０】本実施の形態でも、重畳している電圧が交
流電圧であり、直流電圧のようにシース絶縁抵抗を介し
て生じる迷走電流が増大せず、劣化信号だけが増幅され
る。Also in the present embodiment, the superimposed voltage is an AC voltage, and the stray current generated via the sheath insulation resistance does not increase unlike the DC voltage, and only the deteriorated signal is amplified.
【００４１】上述した他の実施の形態によれば、電力ケ
ーブルの遮へい層に商用周波数の１倍＋ａＨｚの交流電
圧を印加しているが、一般的には、商用周波数の奇数倍
＋ａＨｚの交流電圧を印加した場合、ａＨｚ程度の電圧
を変動させたと同じような効果が得られ易く、この交流
電圧を印加する前後の直流成分電流（平均値）の差から
電力ケーブルの絶縁劣化を診断できる。さらに、コンデ
ンサを挿入するなどの手段によって迷走電流を除去でき
る他、交流電圧を重畳しているので、シース絶縁抵抗を
介して生じる迷走電流は極めて小さくなっている。According to the other embodiment described above, an AC voltage of 1 times the commercial frequency + aHz is applied to the shielding layer of the power cable. In general, an AC voltage of an odd multiple of the commercial frequency + aHz is applied. Is applied, the same effect as when a voltage of about a Hz is fluctuated is easily obtained, and the insulation deterioration of the power cable can be diagnosed from the difference of the DC component current (average value) before and after the application of the AC voltage. Furthermore, the stray current can be removed by inserting a capacitor or the like, and since the AC voltage is superimposed, the stray current generated via the sheath insulation resistance is extremely small.
【００４２】なお、上述した実施の形態では、ａの値を
1.4Ｈｚにしているが、この値は１０Ｈｚ以下の任意の
値としても上述したと同様の作用効果が得られる。In the above embodiment, the value of a is
Although the frequency is set to 1.4 Hz, the same effect as described above can be obtained even if the value is set to an arbitrary value of 10 Hz or less.
【００４３】上述した実施の形態によれば、電力ケーブ
ルの遮へい層に印加する交流電圧の周波数は、商用周波
数の整数倍＋ａＨｚとしているが、更に他の実施の形態
として、交流電源５の交流電圧発生回路５ａが商用周波
数の整数（２以上）分の１倍±ａＨｚ（０＜ａ≦１０）
の周波数の交流電圧を発生している場合について説明す
る。According to the above-described embodiment, the frequency of the AC voltage applied to the shielding layer of the power cable is set to an integer multiple of the commercial frequency + a Hz. The generation circuit 5a is an integer (2 or more) times the commercial frequency ± aHz (0 <a ≦ 10)
A case where an AC voltage having a frequency of?
【００４４】一般的には、下式を満足する周波数の交流
電圧を印加するようにしても、劣化信号を得ることがで
きる。 ｆ＝（Ｆ／ｎ）±ａ（０＜ａ≦１０） 式中、ｆは印加電圧の周波数（Ｈｚ）、Ｆは商用周波数
（Ｈｚ）、ｎは整数（ｎ≧２）である。このような交流
電圧を印加したとき得られる劣化信号の周波数ｆ′は、
下式のようになる。 ｆ′＝｜ｎｆ−Ｆ｜Generally, a deteriorated signal can be obtained even when an AC voltage having a frequency satisfying the following equation is applied. f = (F / n) ± a (0 <a ≦ 10) where f is the frequency (Hz) of the applied voltage, F is the commercial frequency (Hz), and n is an integer (n ≧ 2). The frequency f ′ of the degraded signal obtained when such an AC voltage is applied is
It becomes like the following formula. f '= | nf-F |
【００４５】図５は劣化ケーブルに３１Ｈｚ（Ｆ＝６０
Ｈｚ、ｎ＝２、ａ＝１）、５０Ｖの電圧を重畳した結果
をグラフでそれぞれ示し、下表３は結果を要約して示
す。図５から明らかなように、劣化ケーブルでは約２Ｈ
ｚ（ｆ′＝｜ｎｆ−Ｆ｜＝｜２×３１−６０｜）程度の
周波数の劣化信号が明確に現れる。これらのことより、
約２Ｈｚ程度の周波数を示す電流の大きさ、特にピーク
・ピーク値、すなわち、Ｉdc max 及びＩdc min から電
力ケーブルの絶縁劣化の程度を評価できる。FIG. 5 shows that 31 Hz (F = 60) is applied to the deteriorated cable.
Hz, n = 2, a = 1), and the results of superimposing a voltage of 50 V are shown in graphs, and Table 3 below summarizes the results. As is apparent from FIG. 5, the deteriorated cable has about 2H.
A deteriorated signal having a frequency of about z (f '= | nf-F | = | 2 × 31-60 |) appears clearly. Than these things,
The degree of insulation deterioration of the power cable can be evaluated from the magnitude of the current showing a frequency of about 2 Hz, particularly the peak-to-peak value, that is, Idcmax and Idcmin.
【００４６】[0046]
【表３】 [Table 3]
【００４７】[0047]
【発明の効果】以上説明したように請求項１記載の本発
明の方法によれば、電力ケーブルの遮へい層に交流電源
によって商用周波数の整数倍±ａＨｚ（０＜ａ≦１０）
の周波数の交流電圧を印加することにより、略ａＨｚの
電圧を重畳したり略ａＨｚで印加電圧を変化させたと同
じような効果が得られ、電力ケーブルに絶縁劣化があれ
ば、電力ケーブルから交流電源によって接地に絶縁劣化
の程度に応じた大きさの電流が流れるようになるので、
電流測定手段により測定した電力ケーブルから交流電源
を介して接地に流れる電流に基づいて診断手段が電力ケ
ーブルの水トリーによる真の絶縁劣化の程度を活線状態
で簡単にかつ高い精度で診断することができる。As described above, according to the method of the first aspect of the present invention, the AC power supply is provided on the shielding layer of the power cable.
The commercial frequency is an integral multiple ± aHz (0 <a ≦ 10 )
By applying an alternating voltage of a frequency, similar effects can be obtained with an applied voltage was varied in a substantially aHz or superimposing a voltage of approximately aHz, if any insulation deterioration in power cables, AC power from the power cables As a result, a current of a magnitude corresponding to the degree of insulation deterioration flows through the ground,
AC power from the power cable measured by the current measuring means
The diagnostic means can easily and accurately diagnose the degree of the real insulation deterioration due to the water tree of the power cable in the live state based on the current flowing to the ground via the power cable.
【００４８】請求項２記載の本発明の方法によれば、電
力ケーブルから接地に流れる絶縁劣化の程度に応じた大
きさの電流が略ａＨｚの周期で変化することに着目し、
電力ケーブルから交流電源を介して接地に流れる略ａＨ
ｚの電流成分を電流測定手段により測定し、測定した略
ａＨｚの電流成分の大きさにより診断手段が電力ケーブ
ルの絶縁劣化の程度を活線状態で診断しているので、他
の要因による電流を簡単に分離でき、水トリーによる真
の絶縁劣化の程度を活線状態で簡単にかつ高い精度で診
断することができる。According to the method of the present invention described in claim 2, attention is paid to the fact that a current having a magnitude corresponding to the degree of insulation deterioration flowing from the power cable to the ground changes at a cycle of approximately a Hz.
Approximately aH flowing from power cable to ground via AC power supply
The current component of z is measured by the current measuring unit , and the diagnostic unit diagnoses the degree of insulation deterioration of the power cable in a live state based on the measured magnitude of the current component of approximately a Hz. It can be easily separated, and the degree of true insulation deterioration due to the water tree can be diagnosed easily and with high accuracy in a live state.
【００４９】請求項３記載の本発明の方法によれば、電
力ケーブルの遮へい層に交流電源により商用周波数の奇
数倍±ａＨ（０＜ａ≦１０）の周波数の交流電圧を印加
することにより、略ａＨｚで印加電圧を変化したと同じ
ようになり、電力ケーブルに絶縁劣化があれば、電力ケ
ーブルから交流電源を介して接地に絶縁劣化の程度に応
じた大きさの直流電流成分が流れるので、電流測定手段
により測定した電力ケーブルから交流電源を介して接地
に流れる直流電流成分の平均値と交流電圧印加前の平均
値との差の大きさにより診断手段が電力ケーブルの水ト
リーによる真の絶縁劣化の程度を活線状態で簡単にかつ
高い精度で診断することができる。According to the method of the present invention, an AC voltage having a frequency of an odd multiple of the commercial frequency ± aH (0 <a ≦ 10) is applied to the shielding layer of the power cable by the AC power supply . This is the same as changing the applied voltage at approximately aHz, and if there is insulation deterioration in the power cable, a DC current component having a magnitude corresponding to the degree of insulation deterioration flows from the power cable to the ground via the AC power supply . Current measuring means
From power cable measured by AC power supply to ground
Diagnosis means diagnoses the degree of true insulation degradation due to water tree of power cable easily and with high accuracy in the live state based on the magnitude of the difference between the average value of the DC current component flowing through and the average value before applying the AC voltage can do.
【００５０】請求項４記載の方法によれば、電力ケーブ
ルの遮へい層に商用周波数の整数（２以上）分の１倍±
ａＨｚ（０＜ａ≦１０）の周波数の交流電圧を印加する
ことにより、略整数倍×ａＨｚで印加電圧を変化したり
略整数倍×ａＨｚの電圧を重畳したと同じようになり、
電力ケーブルに絶縁劣化があれば、電力ケーブルから交
流電源を介して接地に絶縁劣化の程度に応じた大きさの
電流が流れるので、電流測定手段により測定した電力ケ
ーブルから交流電源を介して接地に流れる電流に基づい
て診断手段が電力ケーブルの水トリーによる真の絶縁劣
化の程度を活線状態で簡単にかつ高い精度で診断するこ
とができる。According to the fourth aspect of the present invention, the shielding layer of the power cable has an integral (two or more) times ± 1 times the commercial frequency.
By applying an AC voltage having a frequency of 0 Hz (0 <a ≦ 10), it becomes the same as changing the applied voltage at approximately an integral multiple × aHz or superimposing a voltage of approximately an integral multiple × aHz,
If there is insulation deterioration in the power cable, exchange from the power cable
Since a current of a magnitude corresponding to the degree of insulation deterioration flows to the ground via the power supply, the power cable measured by the current measuring means
Based on the current flowing from the cable to the ground via the AC power supply, the diagnosis means can easily and accurately diagnose the degree of the actual insulation deterioration due to the water tree of the power cable in a live state.
【００５１】請求項５記載の本発明の装置によれば、活
線下で測定対象とする電力ケーブルの遮へい層と接地間
に接続された接地線の途中に設けられた交流電源が、遮
へい層に商用周波数の整数倍±ａＨｚ（０＜ａ≦１０）
の周波数の交流電圧を印加することにより、略ａＨｚで
印加電圧を変化したり略ａＨｚの電圧を重畳したと同じ
ようになり、電力ケーブルに絶縁劣化があれば、電力ケ
ーブルから接地に絶縁劣化の程度に応じた大きさの電流
が流れるので、この電流を測定電流測定手段により測定
することにより、この測定した電流に基づいて診断手段
により電力ケーブルの水トリーによる真の絶縁劣化の程
度が活線状態で簡単にかつ高精度で診断することができ
る。According to the device of the present invention, the AC power supply provided in the middle of the ground wire connected between the shield layer and the ground of the power cable to be measured under the live line is provided with the shield layer. Integer multiple of commercial frequency ± aHz (0 <a ≦ 10)
By applying an AC voltage having a frequency of the above, it becomes the same as changing the applied voltage at approximately aHz or superimposing a voltage of approximately aHz, and if there is insulation deterioration in the power cable, the insulation deterioration from the power cable to the ground may occur. Since a current of a magnitude corresponding to the degree flows, the current is measured by the measuring current measuring means, and based on the measured current, the degree of the real insulation deterioration due to the water tree of the power cable is determined by the diagnostic means based on the live current. Diagnosis can be made easily and with high accuracy in the state.
【００５２】請求項６記載の本発明の装置によれば、電
力ケーブルから接地に流れる絶縁劣化の程度に応じた大
きさの電流が略ａＨｚの周期で変化することに着目し、
電流測定手段がこの略ａＨｚの電流成分を測定し、測定
した略ａＨｚの電流成分の大きさにより電力ケーブルの
絶縁劣化の程度を活線状態で診断しているので、他の要
因による電流を簡単に分離でき、水トリーによる真の絶
縁劣化の程度を活線状態で簡単にかつ高い精度で診断す
ることができる。According to the apparatus of the present invention, attention is paid to the fact that a current having a magnitude corresponding to the degree of insulation deterioration flowing from the power cable to the ground changes at a cycle of approximately a Hz.
The current measuring means measures the current component of approximately a Hz, and diagnoses the degree of insulation deterioration of the power cable in a live state based on the magnitude of the measured current component of approximately a Hz. It is possible to easily and accurately diagnose the degree of insulation degradation due to the water tree in a live state.
【００５３】請求項７記載の本発明の装置によれば、交
流電源が電力ケーブルの遮へい層に商用周波数の奇数倍
±ａＨ（０＜ａ≦１０）の周波数の交流電圧を印加する
ことにより、略ａＨｚで印加電圧を変化したと同じよう
になり、電力ケーブルに絶縁劣化があれば、電力ケーブ
ルから接地に絶縁劣化の程度に応じた大きさの直流電流
成分が流れるので、電流測定手段が測定した直流電流成
分の平均値と交流電圧印加前の平均値との差の大きさに
より電力ケーブルの水トリーによる真の絶縁劣化の程度
を活線状態で簡単にかつ高い精度で診断することができ
る。According to the apparatus of the present invention, the AC power supply applies an AC voltage having a frequency of an odd multiple of the commercial frequency ± aH (0 <a ≦ 10) to the shielding layer of the power cable, This is the same as changing the applied voltage at approximately aHz. If insulation degradation occurs in the power cable, a direct current component having a magnitude corresponding to the degree of insulation degradation flows from the power cable to the ground. The magnitude of the difference between the average value of the DC current component and the average value before the AC voltage is applied makes it possible to easily and accurately diagnose the degree of true insulation deterioration due to water tree of the power cable in a live state. .
【００５４】請求項８記載の本発明の装置によれば、活
線下で測定対象とする電力ケーブルの遮へい層と接地間
に接続された接地線の途中に設けられた交流電源が、遮
へい層に商用周波数の整数（２以上）分の１倍±ａＨｚ
（０＜ａ≦１０）の周波数の交流電圧を印加することに
より、略整数倍×ａＨｚで印加電圧を変化したり略整数
倍×ａＨｚの電圧を重畳したと同じようになり、電流測
定手段により測定する電流を、印加した交流電圧の周波
数及び整数の積と商用周波数との差の絶対値に略等しい
周波数の電流成分とすることで、電力ケーブルに絶縁劣
化があれば、電力ケーブルから接地に絶縁劣化の程度に
応じた大きさの電流が流れるので、この電流を電流測定
手段により測定することにより、この測定した電流に基
づいて診断手段により電力ケーブルの水トリーによる真
の絶縁劣化の程度が活線状態で簡単にかつ高精度で診断
することができる。According to the apparatus of the present invention, the AC power supply provided in the middle of the ground wire connected between the shield layer and the ground of the power cable to be measured under the live line is provided with the shield layer. 1 times the commercial frequency (2 or more) ± aHz
By applying an alternating voltage of a frequency of (0 <a ≦ 10), just as would a superimposed voltage of substantially an integral multiple × substantially integer times × or change the applied voltage in a Hz a Hz, current measurement
The current measured by the
Almost equal to the absolute value of the difference between the product of numbers and integers and the commercial frequency
By setting the current component of the frequency, if there is insulation deterioration in the power cable, a current having a magnitude corresponding to the degree of insulation deterioration flows from the power cable to the ground, and this current is measured by the current measuring means. Based on the measured current, the diagnosis unit can easily and highly accurately diagnose the degree of the actual insulation deterioration due to the water tree of the power cable in a live state.
【図１】本発明による活線電力ケーブルの絶縁劣化診断
方法を実施するのに使用する装置の概略構成を示す図で
ある。FIG. 1 is a diagram showing a schematic configuration of an apparatus used for performing a method for diagnosing insulation deterioration of a live power cable according to the present invention.
【図２】図１の交流電源によって１２１.4Ｈｚの４００
Ｖの交流電圧を印加したときのＡ〜Ｂ間の電位差を示す
グラフである。FIG. 2 shows a 121.4 Hz 400 with the AC power supply of FIG.
6 is a graph showing a potential difference between A and B when a V AC voltage is applied.
【図３】図１の交流電源によって１２１.4Ｈｚの４００
Ｖの交流電圧を印加したとき電力ケーブルに流れる電流
を劣化ケーブル及び新品ケーブルの場合を対比して示す
グラフである。FIG. 3 shows a 121.4 Hz 400 with the AC power supply of FIG.
4 is a graph showing a current flowing through a power cable when an AC voltage of V is applied, in comparison with a case of a deteriorated cable and a case of a new cable.
【図４】図１の交流電源によって６１.4Ｈｚの４００Ｖ
の交流電圧を印加したときのＡ〜Ｂ間の電位差を示すグ
ラフである。4 is 400 V at 61.4 Hz by the AC power supply shown in FIG. 1.
4 is a graph showing a potential difference between A and B when the AC voltage of FIG.
【図５】図１の交流電源によって３１Ｈｚの５０Ｖの交
流電圧を印加したとき電力ケーブルに流れる電流測定結
果を示すグラフである。5 is a graph showing a result of measuring a current flowing through a power cable when an AC voltage of 31 Hz and 50 V is applied by the AC power supply of FIG. 1;
３ 電力ケーブル ３ａ 遮へい層 ４ 接地線 ５ 交流電源 ５ａ 交流電圧発生回路 ５ｂ 変圧器 ６ 電流測定装置（電流測定手段） ７ 診断装置（診断手段） Reference Signs List 3 power cable 3a shielding layer 4 ground wire 5 AC power supply 5a AC voltage generation circuit 5b transformer 6 current measuring device (current measuring means) 7 diagnostic device (diagnosing means)
───────────────────────────────────────────────────── フロントページの続き (72)発明者 堀田 昌弘 静岡県沼津市大岡2771 矢崎電線株式会 社内 審査官 尾崎 淳史 (56)参考文献 特開 平７−294588（ＪＰ，Ａ) 特開 平６−258363（ＪＰ，Ａ) 特開 平６−148255（ＪＰ，Ａ) 特開 昭61−251776（ＪＰ，Ａ) 特開 平８−285903（ＪＰ，Ａ) 特開 平９−5370（ＪＰ，Ａ) 特開 平10−160778（ＪＰ，Ａ) (58)調査した分野(Int.Cl.7，ＤＢ名) G01R 31/02,31/08,31/12 G01R 27/00 - 27/18 ──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Masahiro Hotta 2771 Ooka, Numazu-shi, Shizuoka Yazaki Electric Wire & Cable Co., Ltd. In-house examiner Atsushi Ozaki (56) References JP-A-7-294588 (JP, A) JP-A-6-294 258363 (JP, A) JP-A-6-148255 (JP, A) JP-A-61-251776 (JP, A) JP-A-8-285903 (JP, A) JP-A-9-5370 (JP, A) JP-A-10-160778 (JP, A) (58) Fields investigated (Int. Cl. 7 , DB name) G01R 31/02, 31/08, 31/12 G01R 27/00-27/18
Claims (8)
遮へい層に交流電源によって商用周波数の整数倍±ａＨ
ｚ（０＜ａ≦１０）の周波数の交流電圧を印加し、 前記電力ケーブルから前記交流電源を介して接地に流れ
る電流を電流測定手段により測定し、 該電流測定手段により測定した電流に基づいて診断手段
により前記電力ケーブルの絶縁劣化の程度を活線状態で
診断することを特徴とする活線電力ケーブルの絶縁劣化
診断方法。1. An AC power source forms an integral multiple of a commercial frequency ± aH on a shielding layer of a power cable to be measured under a live line.
z an AC voltage of a frequency of (0 <a ≦ 10) is applied, via the AC power from the power cable was measured by the current measuring means a current flowing to the ground, based on the current measured by said current measuring means Diagnostic means
A method of diagnosing the degree of insulation deterioration of the power cable in a live state by the method.
略ａＨｚの電流成分であり、前記診断手段が前記 略ａＨｚの電流成分の大きさにより
前記診断を行うことを特徴とする請求項１記載の活線電
力ケーブルの絶縁劣化診断方法。Wherein a current component substantially aHz current measured by said current measuring means, according to claim 1, wherein said diagnostic means and performs the diagnosis by the magnitude of the current component of the substantially aHz A method for diagnosing insulation deterioration of live power cables.
直流電流成分であり、前記診断手段が前記交流電圧印加
時の前記直流電流成分の平均値と前記交流電圧印加前の
直流電流成分の平均値との差により前記診断を行うこと
を特徴とする請求項１記載の活線電力ケーブルの絶縁劣
化診断方法。Wherein a current is direct current component measured by said current measuring means, said diagnosis means the average value of the DC current component before the AC voltage applied to the average value of the DC current component at said AC voltage is applied The method for diagnosing deterioration of insulation of a live power cable according to claim 1, wherein the diagnosis is performed based on a difference from the above.
遮へい層に交流電源によって商用周波数の整数（２以
上）分の１倍±ａＨｚ（０＜ａ≦１０）の周波数の交流
電圧を印加し、 前記電力ケーブルから前記交流電源を介して接地に流れ
る電流を電流測定手段により測定し、 該電流測定手段により測定した電流に基づいて前記診断
手段が前記電力ケーブルの絶縁劣化の程度を活線状態で
診断し、 前記電流測定手段により測定する電流が、前記印加した
交流電圧の周波数及び前記整数の積と前記商用周波数と
の差の絶対値に略等しい周波数の電流成分であり、 前記診断手段が該電流成分の大きさにより前記診断を行
う ことを特徴とする活線電力ケーブルの絶縁劣化診断方
法。4. An AC voltage having a frequency of 1 / aHz (0 <a ≦ 10) times an integral number (2 or more) of the commercial frequency is applied to a shielding layer of a power cable to be measured under a live line by an AC power supply. and, via the AC power from the power cable was measured by the current measuring means a current flowing to the ground, the diagnosis based on the current measured by said current measuring means
The means diagnoses the degree of insulation deterioration of the power cable in a live state, and the current measured by the current measuring means is applied to the power cable .
The product of the frequency of the AC voltage and the integer and the commercial frequency
Current component having a frequency substantially equal to the absolute value of the difference between the current components, and the diagnostic means performs the diagnosis based on the magnitude of the current component.
Insulation degradation diagnosis method of hot power cables, characterized in that the Hare.
遮へい層と接地間に接続された接地線の途中に設けら
れ、前記遮へい層に商用周波数の整数倍±ａＨｚ（０＜
ａ≦１０）の周波数の交流電圧を印加する交流電源と、 前記電力ケーブルから前記交流電源及び前記接地線を介
して接地に流れる電流を測定する電流測定手段と、 該電流測定手段により測定した電流に基づいて前記電力
ケーブルの絶縁劣化の程度を活線状態で診断する診断手
段とを備えることを特徴とする活線電力ケーブルの絶縁
劣化診断装置。5. An electric power cable to be measured under a live line, which is provided in the middle of a ground line connected between a shield layer and the ground, and the shield layer has an integral multiple of a commercial frequency ± a Hz (0 <
a ≦ 10) an AC power supply for applying an AC voltage having a frequency of: a current measuring means for measuring a current flowing from the power cable to the ground via the AC power supply and the ground wire, and a current measured by the current measuring means. Diagnostic means for diagnosing the degree of insulation deterioration of the power cable in a live state based on the condition.
を測定し、 前記診断手段が前記略ａＨｚの電流成分の大きさにより
診断を行うことを特徴とする請求項５記載の活線電力ケ
ーブルの絶縁劣化診断装置。6. The live-line power cable according to claim 5, wherein said current measuring means measures a current component of approximately a Hz, and said diagnostic means performs diagnosis based on a magnitude of said current component of approximately a Hz. Insulation deterioration diagnostic equipment.
記診断手段が前記交流電圧印加時の前記直流電流成分の
平均値と前記交流電圧印加前の直流電流成分の平均値と
の差により診断を行うことを特徴とする請求項５記載の
活線電力ケーブルの絶縁劣化診断装置。7. The method according to claim 6, wherein the measurement current is a DC current component, and the diagnosis unit diagnoses the difference between an average value of the DC current component when the AC voltage is applied and an average value of the DC current component before the AC voltage is applied. The apparatus for diagnosing deterioration of insulation of a live power cable according to claim 5, wherein
遮へい層と接地間に接続された接地線の途中に設けら
れ、前記遮へい層に商用周波数の整数（２以上）分の１
倍±ａＨｚ（０＜ａ≦１０）の周波数の交流電圧を印加
する交流電源と、 前記電力ケーブルから前記交流電源及び前記接地線を介
して接地に流れる電流を測定する電流測定手段と、 該電流測定手段により測定した電流に基づいて前記電力
ケーブルの絶縁劣化の程度を活線状態で診断する診断手
段とを備え、 前記電流測定手段により測定する電流が、前記印加した
交流電圧の周波数及び前記整数の積と前記商用周波数と
の差の絶対値に略等しい周波数の電流成分であり、 前記診断手段が該電流成分の大きさにより前記診断を行
う ことを特徴とする活線電力ケーブルの絶縁劣化診断装
置。8. A power cable, which is provided under a live line, is provided in the middle of a ground line connected between a shield layer and a ground of a power cable to be measured, and the shield layer has an integer (2 or more) of a commercial frequency.
An AC power supply for applying an AC voltage having a frequency of ± aHz (0 <a ≦ 10); current measuring means for measuring a current flowing from the power cable to the ground via the AC power supply and the ground wire; Diagnosing means for diagnosing the degree of insulation deterioration of the power cable in a live state based on the current measured by the measuring means , wherein the current measured by the current measuring means is applied.
The product of the frequency of the AC voltage and the integer and the commercial frequency
Current component having a frequency substantially equal to the absolute value of the difference between the current components, and the diagnostic means performs the diagnosis based on the magnitude of the current component.
Cormorant possible insulation degradation diagnosis apparatus hot power cable according to claim.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP03910197A JP3317391B2 (en) | 1996-02-23 | 1997-02-24 | Method and apparatus for diagnosing insulation deterioration of a live power cable |
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3638796 | 1996-02-23 | ||
| JP8-36387 | 1996-02-23 | ||
| JP03910197A JP3317391B2 (en) | 1996-02-23 | 1997-02-24 | Method and apparatus for diagnosing insulation deterioration of a live power cable |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH09318696A JPH09318696A (en) | 1997-12-12 |
| JP3317391B2 true JP3317391B2 (en) | 2002-08-26 |
Family
ID=26375429
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP03910197A Expired - Lifetime JP3317391B2 (en) | 1996-02-23 | 1997-02-24 | Method and apparatus for diagnosing insulation deterioration of a live power cable |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3317391B2 (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR101032778B1 (en) * | 2009-03-13 | 2011-05-06 | 주식회사 경신 | Wire harness energization inspection jig |
| KR101032780B1 (en) * | 2009-03-13 | 2011-05-06 | 주식회사 경신 | Shield Wire Inspection Jig |
| KR101032779B1 (en) * | 2009-03-13 | 2011-05-06 | 주식회사 경신 | Shield Wire Inspection Jig |
| KR101032781B1 (en) * | 2009-03-13 | 2011-05-06 | 주식회사 경신 | Shield Wire Inspection Jig |
| JP6974111B2 (en) * | 2016-11-17 | 2021-12-01 | 矢崎エナジーシステム株式会社 | Power cable insulation deterioration detection device and insulation deterioration detection method |
| WO2021107289A1 (en) | 2019-11-28 | 2021-06-03 | 엘에스일렉트릭㈜ | Insulation monitoring device and control method therefor |
-
1997
- 1997-02-24 JP JP03910197A patent/JP3317391B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH09318696A (en) | 1997-12-12 |
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