JPH0119105B2 - - Google Patents
Info
- Publication number
- JPH0119105B2 JPH0119105B2 JP56007916A JP791681A JPH0119105B2 JP H0119105 B2 JPH0119105 B2 JP H0119105B2 JP 56007916 A JP56007916 A JP 56007916A JP 791681 A JP791681 A JP 791681A JP H0119105 B2 JPH0119105 B2 JP H0119105B2
- Authority
- JP
- Japan
- Prior art keywords
- deterioration
- cable
- potential
- input impedance
- measuring
- 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
Links
- 230000006866 deterioration Effects 0.000 claims description 17
- 238000000034 method Methods 0.000 claims description 11
- 239000004020 conductor Substances 0.000 claims description 7
- 238000009413 insulation Methods 0.000 description 8
- 238000005259 measurement Methods 0.000 description 8
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 7
- 240000005572 Syzygium cordatum Species 0.000 description 3
- 235000006650 Syzygium cordatum Nutrition 0.000 description 3
- 238000010521 absorption reaction Methods 0.000 description 2
- 230000015556 catabolic process Effects 0.000 description 2
- 238000000691 measurement method Methods 0.000 description 2
- 230000035945 sensitivity Effects 0.000 description 2
- 229920003020 cross-linked polyethylene Polymers 0.000 description 1
- 239000004703 cross-linked polyethylene Substances 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 230000006698 induction Effects 0.000 description 1
- 239000012212 insulator Substances 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/50—Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections
- G01R31/58—Testing of lines, cables or conductors
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Testing Of Short-Circuits, Discontinuities, Leakage, Or Incorrect Line Connections (AREA)
Description
【発明の詳細な説明】
本発明は地中配電線路の劣化判定方法に関す
る。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for determining deterioration of underground power distribution lines.
ケーブル本体、ヘツド部、ジヨイント部等を含
む地中配電線路で発生する絶縁性能の低下による
破壊事故は、水の侵入に起因するものが多い。中
でも、線路のヘツド部あるいはジヨイント部から
水が侵入して、局部的な劣化を生ずるケースが非
常に多い。 Breakdown accidents caused by a decline in insulation performance that occur in underground power distribution lines, including cable bodies, heads, joints, etc., are often caused by water intrusion. In particular, there are many cases in which water enters from the head or joint of the track, causing localized deterioration.
一方、かかる地中配電線路の劣化を検出する方
法として、一般にメガーテスト、直流高圧洩れ電
流法、tanδ法が行われている。 On the other hand, the Megger test, the DC high voltage leakage current method, and the tanδ method are generally used as methods for detecting deterioration of such underground distribution lines.
しかし架橋ポリエチレンケーブルの場合、メガ
ーテスト、直流高圧洩れ電流法では、ケーブルの
絶縁劣化が極度に進行し、破壊事故に到る直前の
状態にならないと検出不可能な欠点があつた。 However, in the case of cross-linked polyethylene cables, the megger test and DC high voltage leakage current method have the disadvantage that the insulation of the cable has deteriorated to an extreme degree and cannot be detected until the cable is on the verge of breakdown.
またtanδ法は、劣化の程度を傾向として反映す
る測定法であるが、実布設線路の測定に際して
は、外部ノイズの影響を受け易く、装置も大がか
りで実用的な測定法とは云えない。 Furthermore, the tan δ method is a measurement method that reflects the degree of deterioration as a trend, but when measuring an actual installed line, it is easily affected by external noise and requires large-scale equipment, so it cannot be called a practical measurement method.
また、吸収電流を利用した吸収電流法も利用さ
れている。これによれば劣化が局部的に生じてい
る場合に、その劣化がかなり進行していないと検
出が困難であるという問題があつた。 Additionally, an absorption current method using absorption current is also used. According to this, there is a problem in that when deterioration occurs locally, it is difficult to detect unless the deterioration has progressed considerably.
本発明はかかる従来の諸問題に鑑みて成された
ものである。地中配電線路における実測の結果、
水に起因する劣化部があると、そこに水の局部電
池作用が生じて一定の直流電位（100mV〜
200mV）が発生していることを見いだした。本
発明はこの現象を利用して配電線路の導体と遮蔽
層との間の直流電位を測定するのみで、絶縁劣化
を容易に判定できる様にした地中配電線路の劣化
判定方法を提供することを目的とする。 The present invention has been made in view of these conventional problems. Results of actual measurements on underground power distribution lines,
If there is a degraded area caused by water, a local battery effect of water will occur there, resulting in a constant DC potential (100mV ~
200mV) was found to be generated. The present invention utilizes this phenomenon to provide a method for determining deterioration of underground power distribution lines, which allows insulation deterioration to be easily determined by simply measuring the DC potential between the conductor of the power distribution line and the shielding layer. With the goal.
以下に、本発明の実施例について具体的に説明
する。 Examples of the present invention will be specifically described below.
第１図は水トリー劣化ケーブルの発生電位を測
定する方法の１例を示したもので１は被測定ケー
ブル、２は導体、３は絶縁層、４は遮蔽層を示
す、５は直流電位測定用の測定器でこの接続リー
ドを導体２及び遮蔽層４に接続する。このように
すれば絶縁層３の劣化に伴なう直流発生電位を測
定することができる。ただしこの場合、測定器の
入力インピーダンスに注意をはらう必要がある。
すなわち第１図の劣化ケーブル１の等価回路を示
すと第２図に示したようになる。ここでRxは劣
化部を有するケーブルの絶縁抵抗、Cxはケーブ
ル静電容量、Ｅは発生電位である。ここに測定器
の入力インピーダンスRoが接続されるとRoが
Rxに比べて小さい場合は電流はこのRoを流れて
徐々に減衰し低く測定することになる。 Figure 1 shows an example of a method for measuring the potential generated in a water-tree deteriorated cable. 1 is the cable to be measured, 2 is the conductor, 3 is the insulating layer, 4 is the shielding layer, and 5 is DC potential measurement. This connection lead is connected to the conductor 2 and the shielding layer 4 using a suitable measuring device. In this way, it is possible to measure the potential generated by direct current as the insulating layer 3 deteriorates. However, in this case, it is necessary to pay attention to the input impedance of the measuring instrument.
That is, the equivalent circuit of the degraded cable 1 shown in FIG. 1 is shown in FIG. 2. Here, Rx is the insulation resistance of the cable having the deteriorated portion, Cx is the cable capacitance, and E is the generated potential. When the input impedance Ro of the measuring instrument is connected here, Ro becomes
If it is smaller than Rx, the current flows through Ro and gradually attenuates, resulting in a low measurement.
第３図は同一のケーブル試料を入力インピーダ
ンスの異なる測定器で測定した結果を示したもの
であるが入力インピーダンスが10MΩの場合はケ
ーブルの絶縁抵抗が大きいと実際電位が発生して
いても測定できないことも生ずる（なお、上記発
生電位Ｅはそのまま放置しておくと回復し、はじ
めのＥに回復する性質がある。）
これに対し、上記測定器の入力インピーダンス
Roを104MΩとすると第１図の曲線ｂに示す如く
なり、微小な発生電圧をも検出し微妙な劣化状態
をも判別できる。この様に測定器の入力インピー
ダンスRoを大きくすると、実線路に於ける測定
感度を向上することができる。しかし、かかる感
度向上が外部からの誘導障害を受け易くし、却つ
て測定精度を害する場合がある。したがつて実験
によれば、上記入力インピーダンスは104MΩを
限度とすることが望ましい。実用的には10MΩの
入力インピーダンスがあれば劣化部の検出は可能
である。 Figure 3 shows the results of measuring the same cable sample using measuring instruments with different input impedances.If the input impedance is 10MΩ, if the insulation resistance of the cable is large, it will not be possible to measure even if an actual potential is generated. (In addition, if the generated potential E is left as it is, it has the property of recovering to the initial E.) On the other hand, the input impedance of the measuring instrument mentioned above
When Ro is set to 10 4 MΩ, it becomes as shown in curve b in Fig. 1, and even minute generated voltages can be detected and subtle deterioration states can be determined. Increasing the input impedance Ro of the measuring device in this way can improve the measurement sensitivity on an actual line. However, such improvement in sensitivity may make it more susceptible to external induction interference, which may even impair measurement accuracy. Therefore, according to experiments, it is desirable that the input impedance is at most 10 4 MΩ. Practically speaking, it is possible to detect degraded parts with an input impedance of 10 MΩ.
また、上記実験結果から、水が存在する劣化部
に於いては、測定器の入力インピーダンスRoを
10kΩ〜104MΩまで可変すれば、測定される直流
電位Ｅの減少するRoの値から、測定対象の絶縁
抵抗Rxの大よその値が予測できる利点がある。
なお、この様にして検出される直流電位Ｅは水に
起因する劣化の場合にのみ発生するものであり、
他の要因に依る劣化例えばヘツド部の沿面放電に
よるトラツキング、絶縁体界面の部分放電による
電気的トリーイングの様な場合には発生しない。
したがつて、直流電位の測定に依る劣化判定は劣
化要因の判別に対しても有効である。 In addition, from the above experimental results, in the deteriorated part where water is present, the input impedance Ro of the measuring instrument is
If it is varied from 10 kΩ to 10 4 MΩ, there is an advantage that the approximate value of the insulation resistance Rx to be measured can be predicted from the decreasing value of Ro of the measured DC potential E.
Note that the DC potential E detected in this way occurs only in the case of deterioration caused by water.
This does not occur in cases where deterioration is caused by other factors, such as tracking due to creeping discharge in the head section or electrical treeing due to partial discharge at the insulator interface.
Therefore, deterioration determination based on measurement of DC potential is also effective for determining the cause of deterioration.
以上説明した様に、本発明に依れば、地中に埋
設された被測定ケーブルの導体およびこれを絶縁
層を介して被覆する遮蔽層との間の直流電位を、
入力インピーダンスの高い測定器により測定する
ことに依り、事故の大半を占める地中配電線路の
局部的な絶縁劣化を容易かつ確実に判定できると
ともに、劣化要因すなわちその劣化が水に起因す
るものであるかまたはそれ以外の原因によるもの
であるかをも判定できる。 As explained above, according to the present invention, the DC potential between the conductor of the cable to be measured buried underground and the shielding layer covering the conductor through the insulating layer is
By measuring with a measuring device with high input impedance, it is possible to easily and reliably determine the local insulation deterioration of underground power distribution lines, which accounts for the majority of accidents, and also to identify the cause of the deterioration, i.e., that the deterioration is caused by water. It can also be determined whether the problem is caused by other causes.
第１図は被測定ケーブルの直流電位を測定する
測定回路、第２図は本発明に於ける水トリー劣化
部を含む測定回路の等価回路図、第３図は水トリ
ー劣化ケーブルの直流発生電圧対絶縁抵抗特性グ
ラフである。
１…ケーブル、２…導体、３…絶縁層、４…遮
蔽層、５…測定器、Ro…入力インピーダンス。
Figure 1 is a measurement circuit that measures the DC potential of the cable under test, Figure 2 is an equivalent circuit diagram of the measurement circuit including the water tree deteriorated section in the present invention, and Figure 3 is the DC generated voltage of the water tree deteriorated cable. It is a graph of insulation resistance characteristics. 1... Cable, 2... Conductor, 3... Insulating layer, 4... Shielding layer, 5... Measuring device, Ro... Input impedance.
Claims (1)
これを絶縁層を介して覆う遮蔽層との間の直流電
位を、高入力インピーダンスの測定器により測定
することを特徴とする地中配電線路の劣化判定方
法。1. The conductor of the cable under test buried underground,
A method for determining deterioration of an underground power distribution line, the method comprising measuring the direct current potential between the line and a shielding layer covering the line via an insulating layer using a high input impedance measuring device.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP56007916A JPS57122367A (en) | 1981-01-23 | 1981-01-23 | Discriminating method for deterioration of underground distribution line |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP56007916A JPS57122367A (en) | 1981-01-23 | 1981-01-23 | Discriminating method for deterioration of underground distribution line |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS57122367A JPS57122367A (en) | 1982-07-30 |
| JPH0119105B2 true JPH0119105B2 (en) | 1989-04-10 |
Family
ID=11678854
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP56007916A Granted JPS57122367A (en) | 1981-01-23 | 1981-01-23 | Discriminating method for deterioration of underground distribution line |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS57122367A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS58216968A (en) * | 1982-06-11 | 1983-12-16 | Nippon Boshoku Kogyo Kk | Method for detecting quality of insulation coating of reference electrode cable in electrolyte |
-
1981
- 1981-01-23 JP JP56007916A patent/JPS57122367A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS57122367A (en) | 1982-07-30 |
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