JPH01267469A - Method for diagnosing insulation of power cable - Google Patents
Method for diagnosing insulation of power cableInfo
- Publication number
- JPH01267469A JPH01267469A JP9443088A JP9443088A JPH01267469A JP H01267469 A JPH01267469 A JP H01267469A JP 9443088 A JP9443088 A JP 9443088A JP 9443088 A JP9443088 A JP 9443088A JP H01267469 A JPH01267469 A JP H01267469A
- Authority
- JP
- Japan
- Prior art keywords
- power cable
- measuring device
- conductor
- reactor
- current
- 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.)
- Granted
Links
- 238000000034 method Methods 0.000 title claims abstract description 27
- 238000009413 insulation Methods 0.000 title claims abstract description 13
- 239000004020 conductor Substances 0.000 claims abstract description 16
- 238000003745 diagnosis Methods 0.000 claims abstract description 5
- 230000006866 deterioration Effects 0.000 claims description 4
- 230000000694 effects Effects 0.000 abstract description 4
- 230000005674 electromagnetic induction Effects 0.000 abstract description 3
- 238000005259 measurement Methods 0.000 description 6
- 230000006698 induction Effects 0.000 description 3
- 230000007935 neutral effect Effects 0.000 description 3
- 239000003990 capacitor Substances 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 240000005572 Syzygium cordatum Species 0.000 description 1
- 235000006650 Syzygium cordatum Nutrition 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000003292 glue Substances 0.000 description 1
Landscapes
- Measurement Of Resistance Or Impedance (AREA)
Abstract
Description
【発明の詳細な説明】
〔産業上の利用分野〕
本発明は、電力ケーブルの導体と遮蔽層間に流れる電流
の直流成分を測定して、その大きさにより電力ケーブル
の絶縁劣化を診断する方法に関するものである。[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a method for diagnosing insulation deterioration of a power cable by measuring the direct current component of the current flowing between the conductor and the shielding layer of the power cable and based on the magnitude of the DC component. It is something.
活線状態にある電力ケーブルの導体と遮蔽層間に流れる
電流つまり絶縁層を通って流れる電流の直流成分の大き
さは、絶縁層の劣化と密接な関係があることが知られて
いる。従ってこの直流成分を測定すれば、例えばＣＶケ
ーブルの絶縁層が水トリーの発生等のために絶縁劣化が
どの程度進行しているかを診断することができる。It is known that the magnitude of the DC component of the current flowing between the conductor and the shielding layer of a live power cable, that is, the current flowing through the insulating layer, is closely related to the deterioration of the insulating layer. Therefore, by measuring this DC component, it is possible to diagnose, for example, the extent to which insulation deterioration has progressed in the insulation layer of a CV cable due to occurrence of water tree, etc.
従来、この直流成分の測定は図−３のようにして行われ
ている。電力ケーブル１１は導体１２の外周に絶縁層（
開示せず）を介して遮蔽層１３を設けた構造で、導体１
２は高圧母線１４に接続されて活線状態にある。また高
圧母線１４には電源変圧器（または接地変圧器）１５が
接続されている。通常の運転状態では遮蔽層１３の両端
は接地きれているが、直流成分を測定するときは、遮蔽
層１３の一端と大地の間に、交流接地用コンデンサ１６
を並列接続した電流測定器１７を接続し、他端の接地を
開放する。Conventionally, the measurement of this DC component has been carried out as shown in Figure 3. The power cable 11 has an insulating layer (
In this structure, a shielding layer 13 is provided through a conductor 1 (not disclosed).
2 is connected to the high voltage bus 14 and is in a live state. Further, a power transformer (or ground transformer) 15 is connected to the high voltage bus 14 . In normal operating conditions, both ends of the shielding layer 13 are grounded, but when measuring DC components, an AC grounding capacitor 16 is connected between one end of the shielding layer 13 and the ground.
Connect the current measuring device 17, which is connected in parallel, and open the ground at the other end.
これにより遮蔽層１３は、直流的には大地と絶縁され、
交流的には低インピーダンス接地された状態となる。As a result, the shielding layer 13 is insulated from the ground in terms of direct current,
In terms of AC, it is in a low impedance grounded state.
このようにすると直流成分は、高圧充電部から電力ケー
ブルの導体１２−同絶縁層一同遮蔽層１３−電流測定器
１７−大地−変圧器１５−高圧充電部という経路で実線
矢印のように流れる。したがって電流測定器１７の値を
読めば、電力ケーブルの絶縁層に流れる電流の直流成分
が測定できるわけである。In this way, the DC component flows from the high-voltage charging section to the conductor 12 of the power cable, the insulating layer and the shielding layer 13, the current measuring device 17, the ground, the transformer 15, and the high-voltage charging section as shown by the solid line arrow. Therefore, by reading the value of the current measuring device 17, the DC component of the current flowing through the insulation layer of the power cable can be measured.
しかし遮蔽層１３には電磁誘導や迷走電流による電位１
８が発生することがあり、このような電位１８が発生す
ると、それによって点線矢印のような電流が電流測定器
１７に流れるため、測定値に誤差が生じ、絶縁診断を誤
るおそれがある。However, the shielding layer 13 has a potential of 1 due to electromagnetic induction and stray current.
8 may occur, and when such a potential 18 occurs, a current as indicated by the dotted line arrow flows through the current measuring device 17, causing an error in the measured value, and there is a risk of erroneous insulation diagnosis.
このため図−４に示すように、電力ケーブルの遮蔽層１
３は接地したままとし、電源変圧器（または接地変圧器
）１５の中性点と大地の間に電流測定器１７を接続して
測定を行う方法も提案されている。Therefore, as shown in Figure 4, the shielding layer 1 of the power cable
3 remains grounded, and a method is proposed in which a current measuring device 17 is connected between the neutral point of the power transformer (or grounding transformer) 15 and the earth to perform measurements.
このようにすれば遮蔽層１３が接地されているので、！
磁誘導や迷走電流の影響を受けなくて済むことになる。In this way, the shielding layer 13 is grounded, so!
This means that there is no need to be affected by magnetic induction or stray current.
しかしこの方法の難点は、電源変圧器または接地変圧器
には一般に堅牢な配線がなされているため活線状態で電
流測定器を挿入する作業がきわめて困難であり、また安
全性にも問題があるということである。However, the disadvantage of this method is that power transformers or grounding transformers generally have robust wiring, making it extremely difficult to insert a current measuring device while the wires are live, and there are also safety issues. That's what it means.
本発明は、上記のような課題を解決し、精度よく、かつ
容易に絶縁診断を行える方法を提供するもので、その方
法は、電力ケーブルの導体と遮蔽層間に流れる電流の直
流成分を測定して、その大きさにより電力ケーブルの絶
縁劣化を診断する方法において、電力ケーブルの導体に
リアクトルの一端を接続し、そのリアクトルの他端と大
地の間に電流測定器を接続すると共に、電力ケーブルの
遮蔽層を接地し、その状態で電流測定器に流れる直流電
流を測定することを特徴とするものである。The present invention solves the above-mentioned problems and provides a method for easily and accurately diagnosing insulation. In this method, one end of a reactor is connected to the conductor of the power cable, a current measuring device is connected between the other end of the reactor and the ground, and the power cable is This method is characterized in that the shielding layer is grounded and the direct current flowing through the current measuring device is measured in that state.
この方法は、リアクトルを使用することにより活線状態
のケーブル導体に電流測定器を容易に接続できるように
し、また遮蔽層を接地することにより電磁誘導や迷走電
流の影響を排除して、直流成分の測定を容易にかつ正確
に行えるようにしたものである。This method uses a reactor to easily connect a current measuring device to a live cable conductor, and also eliminates the effects of electromagnetic induction and stray current by grounding the shielding layer. This makes it possible to measure easily and accurately.
また電力ケーブルに負荷が接続されていて、その負荷で
発生する直流成分が問題となる場合は、上記の方法にお
いて、電流測定器と大地の間に直流カット用フィルタを
接続すると共に、その電流測定器と直流カット用フィル
タとの間に電力ケーブルの遮蔽層を電気的に接続するこ
とが有効である。In addition, if a load is connected to the power cable and the DC component generated by the load is a problem, use the method described above to connect a DC cut filter between the current measuring device and the ground, and to measure the current. It is effective to electrically connect the shielding layer of the power cable between the device and the DC cut filter.
以下、本発明の実施例を図面を参照して詳細に説明する
。Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
図−１は本発明の一実施例を示すもので、先に説明した
図−３と同一部分には同一符号が付しである。この方法
の特徴は、電力ケーブル１１の導体１２に（高圧母線１
４を介して）交流遮断用のりアクドル２１の一端を接続
し、そのリアクトル２１の他端と大地の間に電流測定器
１７を接続すると共に、電力ケーブルの遮蔽層１３を接
地した状態で、電流測定を行うようにしたことである。FIG. 1 shows an embodiment of the present invention, and the same parts as in FIG. 3 described above are given the same reference numerals. The feature of this method is that the conductor 12 of the power cable 11 (high voltage bus 1
4) is connected to one end of the AC cutoff glue handle 21, and the current measuring device 17 is connected between the other end of the reactor 21 and the ground, and the shielding layer 13 of the power cable is grounded. The purpose of this measure is to carry out measurements.
このようにすれば電流測定器１７は変圧器の中性点に接
続したのと同じ状態となり、また遮蔽層１３が接地され
ているためｉｔＭ１誘導や迷走電流の影響を受けること
もなくなり、電流測定器１７では電力ケーブル１１の絶
縁層を通して流れる電流の直流成分を正確に測定できる
ことになる。なおリアクトル２１の一端は高圧母線１４
に着脱自在に接続できるようにしておくと便利である。In this way, the current measuring device 17 will be in the same state as if it were connected to the neutral point of the transformer, and since the shielding layer 13 is grounded, it will not be affected by itM1 induction or stray current, and the current measurement device 17 will be in the same state as if it were connected to the neutral point of the transformer. The device 17 can accurately measure the DC component of the current flowing through the insulating layer of the power cable 11. Note that one end of the reactor 21 is connected to the high voltage bus 14.
It is convenient to have a device that can be detachably connected to the device.
実験によると、２５０ｍの６．６ＫＶ ＣＶケーブルニ
ついて、図−１の方法と、図−３、図−４の方法で電流
測定を行った結果、図−１と図−４の方法では測定値が
同じ２５ｎ＾であったが、図−３の方法では３１ｎ八と
なった。これにより図−１の方法は図−４の方法と同程
度の精度を有していることが確認された。なお図−１の
方法では１．５Ｈのリアクトルを使用した。According to experiments, current measurements were performed on a 250m long 6.6KV CV cable using the method shown in Figure 1, and the methods shown in Figures 3 and 4. was the same 25n^, but with the method shown in Figure 3 it became 31n8. As a result, it was confirmed that the method shown in Figure 1 has the same level of accuracy as the method shown in Figure 4. In the method shown in Figure 1, a 1.5H reactor was used.
図−２は本発明の他の実施例を示す、電力ケーブル１１
にモーターなどの負荷２２が接続されている場合、その
負荷で発生する直流成分が測定値に影響することがある
ので、この方法は、電流測定器１７と大地の間に直流カ
ット用フィルタ２３を接続すると共に、その電流測定器
１７と直流カット用フィルタ２３との間に電力ケーブル
の遮蔽層１３を電気的に接続することにより、負荷２２
で発生する直流成分の影響を遮断したものである。それ
以外は図−１の実施例と同じである。なおこの方法は、
電力ケーブルに負荷が接続されていない場合にも適用可
能である。FIG. 2 shows another embodiment of the present invention, a power cable 11
When a load 22 such as a motor is connected to a motor, the DC component generated by the load may affect the measured value. Therefore, this method uses a DC cut filter 23 between the current measuring device 17 and the ground. At the same time, by electrically connecting the shielding layer 13 of the power cable between the current measuring device 17 and the DC cut filter 23, the load 22
This is to block the influence of the DC component generated in the The rest is the same as the embodiment shown in FIG. Note that this method is
It is also applicable when no load is connected to the power cable.
以上説明したように本発明によれば、電ｆ！１誘導や迷
走電流の影響を受けることなく直流成分の測定ができる
上、リアクトルを使用したことにより電源変圧器や接地
変圧器の配線を変更することなく電流測定器の接続がで
きるため、配線作業がきわめて簡単になる。またリアク
トルは電力ケーブルのどちらの端末へも接続できるから
、スペースなど都合のよい方の端末で測定作業が行え、
作業の自由度も高い。As explained above, according to the present invention, electric f! 1 DC components can be measured without being affected by induction or stray currents, and by using a reactor, a current measuring device can be connected without changing the wiring of the power transformer or grounding transformer, making wiring work easier. becomes extremely easy. In addition, the reactor can be connected to either terminal of the power cable, so you can perform measurements at the terminal that is most convenient for you, such as space.
There is also a high degree of freedom in work.
図−１および図−２はそれぞれ本発明に係る電力ケーブ
ルの絶縁診断方法の実施例を示す配線図、図−３および
図−４は従来の電力ケーブルの絶縁診断方法を示す配線
図である。
１１：電力ケーブル、１２：導体、１３：遮蔽層、１４
：高圧母線、１５：電源変圧器または接地変圧器、１６
二交流接地用コンデンサ、１７：電流測定器、２１：リ
アクトル、２２：負荷、２３：直流カット用フィルタ。
図−１
図−２
図−３
図−４1 and 2 are wiring diagrams showing an embodiment of the power cable insulation diagnosis method according to the present invention, and FIGS. 3 and 4 are wiring diagrams showing a conventional power cable insulation diagnosis method. 11: Power cable, 12: Conductor, 13: Shielding layer, 14
: High voltage busbar, 15: Power transformer or grounding transformer, 16
Two AC grounding capacitor, 17: Current measuring device, 21: Reactor, 22: Load, 23: DC cut filter. Figure-1 Figure-2 Figure-3 Figure-4
Claims (1)
成分を測定して、その大きさにより電力ケーブルの絶縁
劣化を診断する方法において、電力ケーブルの導体にリ
アクトルの一端を接続し、そのリアクトルの他端と大地
の間に電流測定器を接続すると共に、電力ケーブルの遮
蔽層を接地し、その状態で電流測定器に流れる直流電流
を測定することを特徴とする電力ケーブルの絶縁診断方
法。 ２、電力ケーブルの導体と遮蔽層間に流れる電流の直流
成分を測定して、その大きさにより電力ケーブルの絶縁
劣化を診断する方法において、電力ケーブルの導体にリ
アクトルの一端を接続し、そのリアクトルの他端と大地
の間に、電流測定器と直流カット用フィルタとを後者を
大地側にして直列接続すると共に、上記電流測定器と直
流カット用フィルタとの間に電力ケーブルの遮蔽層を電
気的に接続し、その状態で上記電流測定器に流れる直流
電流を測定することを特徴とする電力ケーブルの絶縁診
断方法。[Claims] 1. A method for diagnosing insulation deterioration of a power cable by measuring the DC component of a current flowing between a conductor of a power cable and a shielding layer based on the magnitude thereof, the method comprises: attaching one end of a reactor to the conductor of the power cable; A power cable is characterized in that a current measuring device is connected between the other end of the reactor and the ground, and a shielding layer of the power cable is grounded, and the direct current flowing through the current measuring device is measured in this state. insulation diagnosis method. 2. In this method, one end of a reactor is connected to the conductor of the power cable, and the reactor is A current measuring device and a DC cut filter are connected in series between the other end and the ground, with the latter facing the ground, and a shielding layer of the power cable is electrically connected between the current measuring device and the DC cutting filter. A method for diagnosing insulation of a power cable, the method comprising: connecting the power cable to the current measuring device, and measuring the direct current flowing through the current measuring device in that state.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP9443088A JP2575456B2 (en) | 1988-04-19 | 1988-04-19 | Power cable insulation diagnostic method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP9443088A JP2575456B2 (en) | 1988-04-19 | 1988-04-19 | Power cable insulation diagnostic method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH01267469A true JPH01267469A (en) | 1989-10-25 |
| JP2575456B2 JP2575456B2 (en) | 1997-01-22 |
Family
ID=14110019
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP9443088A Expired - Lifetime JP2575456B2 (en) | 1988-04-19 | 1988-04-19 | Power cable insulation diagnostic method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2575456B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2022118450A1 (en) * | 2020-12-03 | 2022-06-09 | 三菱電機株式会社 | Power conversion device, motor drive system, and disconnection detection method for signal transmission cable |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108051715B (en) * | 2018-01-08 | 2020-11-03 | 云南电网有限责任公司曲靖供电局 | Air-core reactor turn-to-turn insulation defect detection system and method |
-
1988
- 1988-04-19 JP JP9443088A patent/JP2575456B2/en not_active Expired - Lifetime
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2022118450A1 (en) * | 2020-12-03 | 2022-06-09 | 三菱電機株式会社 | Power conversion device, motor drive system, and disconnection detection method for signal transmission cable |
| US11894784B2 (en) | 2020-12-03 | 2024-02-06 | Mitsubishi Electric Corporation | Power conversion device, motor drive system, and disconnection detection method for signal transmission cable |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2575456B2 (en) | 1997-01-22 |
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