JPH06292325A - Power cable insulation deterioration detecting circuit - Google Patents
Power cable insulation deterioration detecting circuitInfo
- Publication number
- JPH06292325A JPH06292325A JP5076911A JP7691193A JPH06292325A JP H06292325 A JPH06292325 A JP H06292325A JP 5076911 A JP5076911 A JP 5076911A JP 7691193 A JP7691193 A JP 7691193A JP H06292325 A JPH06292325 A JP H06292325A
- Authority
- JP
- Japan
- Prior art keywords
- power cable
- conductor
- circuit
- insulator
- shield conductor
- 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
Landscapes
- Testing Of Short-Circuits, Discontinuities, Leakage, Or Incorrect Line Connections (AREA)
- Emergency Protection Circuit Devices (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、配線された送・配電の
電力用ケーブルの絶縁劣化を検知する検知回路に係り、
詳しくは電力用ケーブルが使用不能になる前に電力用ケ
ーブルの絶縁劣化を検知する絶縁劣化検知回路に関す
る。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a detection circuit for detecting insulation deterioration of a wired power cable for transmission / distribution.
More specifically, the present invention relates to an insulation deterioration detection circuit that detects insulation deterioration of a power cable before it becomes unusable.
【０００２】[0002]
【従来の技術】従来、送・配電用の電力用ケーブルは、
中心部導体の周りを絶縁体で囲み、その絶縁体の周りを
遮蔽導体で囲んだうえ、シ−スで保護するように形成さ
れた一重シ−ス型に形成されている。この従来の電力用
ケーブルは、配線の際、上記遮蔽導体をア−ス接続する
ことにより、上記絶縁体が絶縁破壊を起こしたときの電
流をア−スに通電できるように接続されている。そし
て、上記絶縁体が絶縁破壊を起こしたときは、地絡地点
において、その配電エリアの、即ち、変電所のトランス
単位の対地充電電流が流れ続けるため、変電所の遮断制
御により、当該配電エリアは停電状態になる。2. Description of the Related Art Conventionally, power cables for power transmission and distribution are
The central conductor is surrounded by an insulator, the insulator is surrounded by a shield conductor, and a single sheath type is formed so as to be protected by a sheath. This conventional power cable is connected so that the shield conductor is grounded at the time of wiring, so that a current can be applied to the ground when the insulation breakdown occurs. Then, when the insulator causes a dielectric breakdown, at the ground fault point, the charging current to ground in the distribution area of the substation, that is, in the transformer unit of the substation continues to flow. Goes into a power outage.
【０００３】[0003]
【発明が解決しようとする課題】上記従来の電力用ケー
ブルを用いて配電線路を構成した場合、電力用ケーブル
の絶縁体が絶縁破壊を起こせば、即、地絡し、地絡部分
は破壊して停電状態になる。この状態では電力用ケーブ
ルの交換が必要であり、電力用ケーブルの交換が完了し
た時点で当該配電エリアの復電が可能になる。しかしな
がら、従来は電力ケ−ブルの絶縁破壊を起こす前に、絶
縁体劣化を検知することができないことは勿論、仮に絶
縁劣化診断技術が進んでいるとしても何時、絶縁破壊を
起こすかを事前に判定することは不可能である。また、
突発的に電力ケ−ブルの絶縁破壊が起きた場合、電力ケ
−ブルの交換作業は比較的長時間を要し、その間は停電
状態が継続するため需要家に少なからず影響を与えると
いう問題がある。In the case where a distribution line is constructed by using the above-mentioned conventional power cable, if the insulator of the power cable causes dielectric breakdown, a ground fault occurs immediately, and a ground fault portion is destroyed. Power failure. In this state, the power cable needs to be replaced, and when the power cable has been replaced, the power distribution area can be restored. However, conventionally, it is not possible to detect the insulation deterioration before the insulation breakdown of the power cable, and even if the insulation deterioration diagnosis technology is advanced, it is necessary to know in advance when the insulation breakdown will occur. It is impossible to judge. Also,
When the insulation breakdown of the power cable occurs suddenly, the replacement work of the power cable requires a relatively long time, and during that period, the power outage state continues, so that there is a considerable impact on customers. is there.
【０００４】そこで本発明では、電力用ケーブル絶縁体
の絶縁劣化が進んでも、その絶縁が破壊する前に絶縁劣
化を検知し、事前に電力用ケーブルを交換する等の対策
がとれるようにするとともに、比較的接地抵抗値が高く
ても安全性が保てるようにすることを解決すべき技術的
課題とするものである。Therefore, in the present invention, even if the insulation deterioration of the power cable insulator progresses, the insulation deterioration is detected before the insulation is broken, and measures such as replacing the power cable in advance can be taken. The technical problem to be solved is to maintain the safety even if the ground resistance value is relatively high.
【０００５】[0005]
【課題を解決するための手段】そこで本発明では、上記
課題を解決するための電力用ケーブルの絶縁劣化検知回
路を、電力送電用の内部導体の外周に内部絶縁体と内部
遮蔽導体と外部絶縁体と外部遮蔽導体とシースとが同芯
状に形成され、前記内部導体が交流電源の各相に接続さ
れた電力用ケーブルにおいて、前記外部遮蔽導体それぞ
れをアース接続する一方、前記各電力用ケーブルの内部
遮蔽導体を常閉接点を介してＹ結線した状態で、電位測
定のため高抵抗を介してアースに接続するとともに、前
記内部遮蔽導体中性点とア−ス接続されている外部遮蔽
導体間の電位差を検出し、その電位差が所定値を越えた
ときに短絡故障を防ぐため前記常閉接点を遮断する遮断
回路と、その遮断回路により前記常閉接点が遮断された
とき、前記内部絶縁体の絶縁劣化が進行して前記電力用
ケ−ブルの交換をしなければならないことを示す警報信
号を所要の場所に伝送する制御用回路とを設けた構成に
することである。Therefore, in the present invention, an insulation deterioration detecting circuit for a power cable for solving the above problems is provided in the outer periphery of an inner conductor for power transmission, an inner insulator, an inner shield conductor, and an outer insulation. In a power cable in which a body, an outer shield conductor, and a sheath are formed concentrically, and the inner conductor is connected to each phase of an AC power source, each of the outer shield conductors is grounded, while each power cable is connected. In the state where the inner shield conductor of (1) is Y-connected through the normally closed contact, it is connected to the ground through a high resistance for potential measurement, and the outer shield conductor is grounded to the neutral point of the inner shield conductor. A potential difference between the two is detected, and when the potential difference exceeds a predetermined value, the normally-closed contact is interrupted to prevent a short-circuit failure, and when the normally-closed contact is interrupted by the interruption circuit, the internal disconnection is performed. For said power insulation deterioration progresses body Ke - is to structure provided with a control circuit for transmitting an alarm signal indicating that must be exchanged Bull to the required location.
【０００６】[0006]
【作用】このように構成された電力用ケーブルの絶縁劣
化検知回路において、まず、各電力用ケーブルの内部絶
縁体それぞれの絶縁特性が正常な場合、各内部遮蔽導体
から流れる充電電流はバランスが取れており、Ｙ結線中
性点における対地電圧はほぼゼロに等しいため、電位差
が所定値を越えないことから遮断回路は常閉接点を遮断
しない。従って、制御用回路からは電力用ケ−ブルの交
換をしなければならないことを示す警報信号は出力され
ない。一方、電界のかかっている電力用ケーブルの内部
絶縁体の絶縁が劣化し、内部遮蔽導体と外部遮蔽導体間
の電位差が所定値を越えると、遮断回路は常閉接点を遮
断し、別の各相との短絡故障を防ぐとともに外部絶縁体
により絶縁は維持され、制御用回路は電力用ケ−ブルの
交換を促すための警報信号を所要の場所、例えば変電所
等に伝送する。その結果、内部絶縁体の絶縁劣化情報は
制御用回路によって変電所等に伝えられるため、送電を
停止させることなく当該電力用ケーブルの交換を行うこ
とができる。In the insulation deterioration detecting circuit for a power cable constructed as described above, first, when the insulation characteristics of each inner insulator of each power cable are normal, the charging currents flowing from the respective inner shield conductors are balanced. Since the ground voltage at the neutral point of the Y connection is substantially equal to zero, the potential difference does not exceed the predetermined value, and therefore the breaking circuit does not break the normally closed contact. Therefore, the control circuit does not output an alarm signal indicating that the power cable must be replaced. On the other hand, when the insulation of the inner insulator of the power cable under the electric field deteriorates and the potential difference between the inner shield conductor and the outer shield conductor exceeds a predetermined value, the shutoff circuit shuts off the normally closed contact and Insulation is maintained by an external insulator while preventing short-circuit failure with the phase, and the control circuit transmits an alarm signal for prompting replacement of the power cable to a required place, for example, a substation. As a result, since the insulation deterioration information of the internal insulator is transmitted to the substation or the like by the control circuit, the power cable can be replaced without stopping the power transmission.
【０００７】[0007]
【発明の効果】以上のように本発明によれば、電力用ケ
ーブルの内部絶縁体の絶縁劣化が進行して完全に絶縁破
壊しても、外部絶縁体により絶縁は維持され、電力用ケ
ーブルの絶縁劣化を検知することができるため、送電を
停止させることなく電力用ケーブルの交換を行うことが
できるという効果がある。As described above, according to the present invention, even if the insulation deterioration of the inner insulator of the power cable progresses and the insulation is completely destroyed, the insulation is maintained by the outer insulator and the power cable Since insulation deterioration can be detected, there is an effect that the power cable can be replaced without stopping power transmission.
【０００８】[0008]
【実施例】次に、本発明の実施例について図面を参照し
ながら説明する。図１は、本発明の一実施例の全体的な
構成を示した電気回路図である。また、図２は実施例で
用いられる電力用ケ−ブルの断面図である。最初に、図
２を参照しながら実施例で用いられる電力用ケ−ブル７
の構成を説明する。図２に示すように、電力用ケ−ブル
７は、電力送電用の内部導体１と、その内部導体１の外
周部に同芯状に形成された内部絶縁体２と、内部遮蔽導
体３と、外部絶縁体４と、外部遮蔽導体５と、最外部の
シース６とで構成されている。Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 is an electric circuit diagram showing the overall configuration of an embodiment of the present invention. FIG. 2 is a sectional view of a power cable used in the embodiment. First, the power cable 7 used in the embodiment with reference to FIG.
The configuration of will be described. As shown in FIG. 2, the electric power cable 7 includes an internal conductor 1 for transmitting electric power, an internal insulator 2 which is concentrically formed on the outer peripheral portion of the internal conductor 1, and an internal shield conductor 3. , The outer insulator 4, the outer shield conductor 5, and the outermost sheath 6.
【０００９】上記電力用ケ−ブル７を電力送電用のケ−
ブルとして用いた図１の絶縁劣化検知回路１０に示すよ
うに、電力用ケーブル７の内部導体１は、３相交流電源
Ｐの各相に接続されており、各電力用ケーブル７の外部
遮蔽導体５はアース接続されている。一方、各電力用ケ
ーブル７の内部遮蔽導体３は、常閉の遮断接点８ｂ１、
８ｂ２、８ｂ３を介してＹ結線され、更に電圧検出用抵
抗Ｒを介してアースに接続されている。そして、その電
圧検出用抵抗Ｒには、各電力用ケーブル７の前記内部絶
縁体２の絶縁劣化に伴って内部遮蔽導体３と外部遮蔽導
体５間の電位差を検出する電圧検出器Ｖが接続されてい
る。尚、各電力用ケーブル７の前記内部絶縁体２が絶縁
劣化していない状態では、内部遮蔽導体３から流れ出る
充電電流がバランスしているため、内部遮蔽導体３のＹ
結線中性点と対地間の電位差はほとんどゼロに等しい。The electric power cable 7 is used for electric power transmission.
As shown in the insulation deterioration detection circuit 10 of FIG. 1 used as a cable, the inner conductor 1 of the power cable 7 is connected to each phase of the three-phase AC power supply P, and the outer shield conductor of each power cable 7 is connected. 5 is grounded. On the other hand, the inner shield conductor 3 of each power cable 7 has a normally closed breaking contact 8b1,
It is Y-connected via 8b2 and 8b3, and is further connected to ground via a voltage detecting resistor R. A voltage detector V for detecting a potential difference between the inner shield conductor 3 and the outer shield conductor 5 due to deterioration of insulation of the inner insulator 2 of each power cable 7 is connected to the voltage detection resistor R. ing. In the state where the insulation of the inner insulator 2 of each power cable 7 is not deteriorated, the charging currents flowing out from the inner shield conductor 3 are balanced, so that the Y of the inner shield conductor 3 is Y.
The potential difference between the neutral point and the ground is almost equal to zero.
【００１０】また、各電力用ケーブル７の内部遮蔽導体
３には、それぞれ常閉の遮断接点８ｂ１、８ｂ２、８ｂ
３と直列にＣＴ（変流器）９−１、９−２、９−３が接
続され、各ＣＴ９−１、９−２、９−３はダイオードＤ
−１、Ｄ−２、Ｄ−３を介して並列に接続された状態で
キャパシタＣに接続され、且つ、キャパシタＣは前記常
閉の遮断接点８ｂ１、８ｂ２、８ｂ３を遮断動作させる
作動保持機能付遮断器８の電源として制御用回路１２に
接続されている。Further, the normally-closed breaking contacts 8b1, 8b2, 8b are provided on the inner shield conductor 3 of each power cable 7, respectively.
CT (current transformer) 9-1, 9-2, 9-3 is connected in series with 3, and each CT 9-1, 9-2, 9-3 is a diode D.
-1, D-2, D-3 are connected in parallel and are connected to the capacitor C, and the capacitor C is provided with an operation holding function for breaking the normally closed breaking contacts 8b1, 8b2, 8b3. It is connected to the control circuit 12 as a power source of the circuit breaker 8.
【００１１】尚、各電力用ケーブル７の前記内部絶縁体
２の絶縁劣化に伴って内部遮蔽導体３の中性点とア−ス
線間の電位差が所定値を越え、上記作動保持機能付遮断
器８が作動したとき、制御用回路１２から変電所等に電
力用ケ−ブルの交換を促すための警報信号が信号線１１
を介して伝送される。Incidentally, the potential difference between the neutral point and the ground line of the inner shield conductor 3 exceeds a predetermined value due to the deterioration of the insulation of the inner insulator 2 of each power cable 7, and the cutoff with the operation holding function is performed. When the device 8 is activated, an alarm signal for urging the substation or the like to replace the power cable is sent from the control circuit 12 to the signal line 11.
Is transmitted through.
【００１２】次に、このように構成された電力用ケーブ
ル７の絶縁劣化検知回路１０の作用に説明する。まず、
各電力用ケーブル７の前記内部絶縁体２が絶縁劣化して
いない状態で、内部導体１と内部遮蔽導体３とは内部絶
縁体２により絶縁されているとともに、内部遮蔽導体３
がＹ結線されていることから、前記抵抗Ｒの両端の電圧
はほぼゼロであるため、作動保持機能付遮断器８は作動
しない。Next, the operation of the insulation deterioration detecting circuit 10 of the power cable 7 thus constructed will be described. First,
The inner conductor 2 and the inner shield conductor 3 are insulated from each other by the inner insulator 2 while the inner insulator 2 of each power cable 7 is not deteriorated in insulation.
, The voltage across the resistor R is substantially zero, so that the circuit breaker 8 with the operation holding function does not operate.
【００１３】次に、期間が経過して３本のうちのいずれ
かの電力用ケーブル７の内部絶縁体２の絶縁劣化が進ん
で、内部絶縁体２の絶縁が破壊されると、内部導体１と
内部遮蔽導体３とが導通状態になる。その結果、内部遮
蔽導体３の中性点とア−ス線との間の電位差が所定値を
越えるため、前記抵抗Ｒの両端の電圧は高くなり、電圧
検出器Ｖが所定値を越える電圧を示すとともに、キャパ
シタＣの電源が作動保持機能付遮断器８に放電され、同
遮断器８が作動して遮断接点８ｂ１、８ｂ２、８ｂ３が
開いて別の各相との短絡故障を防ぐとともに、外部絶縁
体４により絶縁は維持される。Next, when the insulation deterioration of the inner insulator 2 of any one of the three power cables 7 progresses due to the passage of time and the insulation of the inner insulator 2 is destroyed, the inner conductor 1 And the internal shield conductor 3 are brought into conduction. As a result, the potential difference between the neutral point of the inner shield conductor 3 and the ground line exceeds a predetermined value, so that the voltage across the resistor R becomes high and the voltage detector V exceeds a predetermined value. At the same time, the power supply of the capacitor C is discharged to the circuit breaker 8 with an operation holding function, the circuit breaker 8 is activated, and the breaking contacts 8b1, 8b2, 8b3 are opened to prevent a short-circuit failure with another phase, and Insulation is maintained by the insulator 4.
【００１４】上記作動保持機能付遮断器８の作動に伴っ
て、制御用回路１２から電力用ケ−ブルの交換を促すた
めの警報信号が信号線１１を介して変電所等に伝送され
る。そのため、一部絶縁破壊された電力用ケーブル７の
交換は、殆ど送電を停止させることなく行うことができ
る。尚、図３は、図１の電気回路の実体配線図を示した
ものである。Along with the operation of the circuit breaker 8 with the operation holding function, an alarm signal for prompting the replacement of the power cable is transmitted from the control circuit 12 to the substation or the like via the signal line 11. Therefore, the power cable 7, which has been partially dielectrically broken down, can be replaced with almost no interruption of power transmission. Note that FIG. 3 shows a substantive wiring diagram of the electric circuit of FIG.
【図１】本発明の一実施例の電気回路図である。FIG. 1 is an electric circuit diagram of an embodiment of the present invention.
【図２】本発明の一実施例における電力用ケーブルの断
面図である。FIG. 2 is a cross-sectional view of a power cable according to an embodiment of the present invention.
【図３】絶縁劣化検知回路の実体配線図である。FIG. 3 is a physical wiring diagram of an insulation deterioration detection circuit.
１ 電力送電用の内部導体 ２ 内部絶縁体 ３ 内部遮蔽導体 ４ 外部絶縁体 ５ 外部遮蔽導体 ６ シース ７ 電力用ケーブル ８ 作動保持機能付遮断器 ８ｂ１ 常閉接点 ８ｂ２ 常閉接点 ８ｂ３ 常閉接点 ９−１ ＣＴ ９−２ ＣＴ ９−３ ＣＴ １０ 絶縁劣化検知回路 １２ 制御用回路 1 inner conductor for power transmission 2 inner insulator 3 inner shield conductor 4 outer insulator 5 outer shield conductor 6 sheath 7 power cable 8 circuit breaker with operation retention function 8b1 normally closed contact 8b2 normally closed contact 8b3 normally closed contact 9- 1 CT 9-2 CT 9-3 CT 10 Insulation deterioration detection circuit 12 Control circuit
Claims (1)
体と内部遮蔽導体と外部絶縁体と外部遮蔽導体とシース
とが同芯状に形成され、前記内部導体が交流電源の各相
に接続された電力用ケーブルにおいて、前記外部遮蔽導
体それぞれをアース接続する一方、前記各電力用ケーブ
ルの内部遮蔽導体を常閉接点を介してＹ結線した状態
で、電位測定のため高抵抗を介してアース接続するとと
もに、前記内部遮蔽導体中性点とア−スに接続されてい
る外部遮蔽導体間の電位差を検出し、その電位差が所定
値を越えたとき短絡故障を防ぐため前記常閉接点を遮断
する遮断回路と、その遮断回路により前記常閉接点が遮
断されたとき前記内部絶縁体の絶縁劣化が進行して前記
電力用ケ−ブルの交換をしなければならないことを示す
警報信号を所要の場所に伝送する制御用回路とを設けた
ことを特徴とする電力用ケーブルの絶縁劣化検知回路。1. An inner insulator, an inner shield conductor, an outer insulator, an outer shield conductor, and a sheath are concentrically formed on the outer periphery of an inner conductor for power transmission, and the inner conductor is provided in each phase of an AC power source. In the connected power cables, while each of the outer shield conductors is grounded, the inner shield conductors of the respective power cables are Y-connected through the normally-closed contacts, and are connected via a high resistance for potential measurement. In addition to grounding, the potential difference between the neutral point of the inner shield conductor and the outer shield conductor connected to the ground is detected, and the normally closed contact is connected to prevent a short circuit failure when the potential difference exceeds a predetermined value. A shutoff circuit for shutting off and an alarm signal indicating that the insulation deterioration of the internal insulator progresses and the power cable must be replaced when the normally closed contact is shut off by the shutoff circuit are required. Location An insulation deterioration detection circuit for a power cable, characterized in that it is provided with a control circuit for transmitting to the power cable.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5076911A JP2569258B2 (en) | 1993-04-02 | 1993-04-02 | Power cable insulation deterioration detection circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5076911A JP2569258B2 (en) | 1993-04-02 | 1993-04-02 | Power cable insulation deterioration detection circuit |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH06292325A true JPH06292325A (en) | 1994-10-18 |
| JP2569258B2 JP2569258B2 (en) | 1997-01-08 |
Family
ID=13618872
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP5076911A Expired - Lifetime JP2569258B2 (en) | 1993-04-02 | 1993-04-02 | Power cable insulation deterioration detection circuit |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2569258B2 (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2003091743A1 (en) * | 2002-04-26 | 2003-11-06 | Kabushiki Kaisha Toshiba | Method for diagnosing deterioration of coil and system for diagnosing deterioration of coil |
| KR100745835B1 (en) * | 2006-02-10 | 2007-08-07 | 파워플러스콤 주식회사 | Leakage current sensor type power off device |
| WO2016137424A1 (en) * | 2015-02-23 | 2016-09-01 | Ge Aviation Systems Llc | Method and apparatus for an electrical fault detecting system for a cable |
| CN113419134A (en) * | 2021-05-18 | 2021-09-21 | 国家电网有限公司 | Method for evaluating safety of secondary cable during power frequency short circuit of grounding grid |
-
1993
- 1993-04-02 JP JP5076911A patent/JP2569258B2/en not_active Expired - Lifetime
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2003091743A1 (en) * | 2002-04-26 | 2003-11-06 | Kabushiki Kaisha Toshiba | Method for diagnosing deterioration of coil and system for diagnosing deterioration of coil |
| KR100745835B1 (en) * | 2006-02-10 | 2007-08-07 | 파워플러스콤 주식회사 | Leakage current sensor type power off device |
| WO2016137424A1 (en) * | 2015-02-23 | 2016-09-01 | Ge Aviation Systems Llc | Method and apparatus for an electrical fault detecting system for a cable |
| US11079425B2 (en) | 2015-02-23 | 2021-08-03 | Ge Aviation Systems Llc | Method and apparatus for an electrical fault detecting system for a circuit |
| CN113419134A (en) * | 2021-05-18 | 2021-09-21 | 国家电网有限公司 | Method for evaluating safety of secondary cable during power frequency short circuit of grounding grid |
| CN113419134B (en) * | 2021-05-18 | 2022-09-02 | 国家电网有限公司 | Method for evaluating safety of secondary cable during power frequency short circuit of grounding grid |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2569258B2 (en) | 1997-01-08 |
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