JPH0525074B2 - - Google Patents
Info
- Publication number
- JPH0525074B2 JPH0525074B2 JP11910085A JP11910085A JPH0525074B2 JP H0525074 B2 JPH0525074 B2 JP H0525074B2 JP 11910085 A JP11910085 A JP 11910085A JP 11910085 A JP11910085 A JP 11910085A JP H0525074 B2 JPH0525074 B2 JP H0525074B2
- Authority
- JP
- Japan
- Prior art keywords
- cable
- conductor
- shielding layer
- lead
- voltage
- 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
- 239000004020 conductor Substances 0.000 claims description 40
- 238000000691 measurement method Methods 0.000 claims description 6
- 238000011084 recovery Methods 0.000 claims description 2
- 238000000034 method Methods 0.000 description 5
- 238000009413 insulation Methods 0.000 description 3
- 239000012212 insulator Substances 0.000 description 3
- 238000005259 measurement Methods 0.000 description 3
- 239000004033 plastic Substances 0.000 description 3
- 230000010287 polarization Effects 0.000 description 3
- 230000006866 deterioration Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 230000005684 electric field Effects 0.000 description 2
- 239000011888 foil Substances 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
Landscapes
- Testing Relating To Insulation (AREA)
Description
【発明の詳細な説明】
［産業上の利用分野］
本発明はケーブルの絶縁劣化診断に使用する残
留電圧の測定方法の改良に関するものである。DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an improvement in a method for measuring residual voltage used for diagnosing insulation deterioration of cables.
［先行技術と問題点］
近来、ケーブルの絶縁劣化診断法の１つとして
残留電圧を測定する方法が提案されている。この
残留電圧法は、遮蔽層が接地された被測定ケーブ
ルの導体に直流高電圧を所定時間前課電し、次い
で、ケーブル導体を所定時間接地し、然る後、ケ
ーブル導体の接地を開放し、この開放後にケーブ
ル導体に回復してくる残留電圧を測定するもので
ある。[Prior Art and Problems] Recently, a method of measuring residual voltage has been proposed as one of the methods for diagnosing cable insulation deterioration. This residual voltage method involves applying a DC high voltage to the conductor of the cable under test whose shielding layer is grounded for a predetermined period of time, then grounding the cable conductor for a predetermined period of time, and then ungrounding the cable conductor. , to measure the residual voltage that recovers in the cable conductor after this release.
この残留電圧の発生メカニズムは、直流課電に
より絶縁体内部に空間電荷または分極が発生し、
その後にケーブルの導体を接地したときに、上記
の空間電荷、分極に対応してケーブル導体及びケ
ーブル外部遮蔽層に誘導電荷が発生してケーブル
導体と遮蔽層の間の電圧を零となるように平衡さ
せ、この誘導電荷発生後にケーブル導体の接地を
開放すれば、その後の絶縁体内部の空間電荷また
は分極の移動または消滅に伴い、上記の空間電荷
と上記の誘導電荷とのバランスが崩れてケーブル
導体とケーブル遮蔽層間に電圧が現われることに
ある。 The mechanism of this residual voltage is that space charge or polarization is generated inside the insulator due to direct current application.
When the cable conductor is then grounded, an induced charge is generated in the cable conductor and the cable outer shielding layer in response to the above space charge and polarization, so that the voltage between the cable conductor and the shielding layer becomes zero. If the cable conductor is grounded after this induced charge is generated, the balance between the above space charge and the above induced charge will be disrupted as the space charge or polarization inside the insulator moves or disappears, causing the cable to It consists in the appearance of a voltage between the conductor and the cable shielding layer.
ところで、残留電圧測定法において、上記した
直流高電圧の前課電並びに接地開放後の残留電圧
の測定には、共通のリードゲーブルを用いてお
り、直流電圧の前課電時にリードゲーブルの絶縁
層にも空間電荷が発生し、これが上記残留電圧の
測定に影響を与え誤差を生じる場合がある。 By the way, in the residual voltage measurement method, a common lead cable is used for pre-charging the above-mentioned DC high voltage and measuring the residual voltage after the ground is disconnected. Space charges are also generated, which may affect the measurement of the residual voltage and cause errors.
［発明の目的］
本発明の目的は、リードケーブルに生じる空間
電荷に起因する測定誤差を排除して被測定ケーブ
ルの残留電圧を正確に測定できる改良された方法
を提供することにある。[Object of the Invention] An object of the present invention is to provide an improved method that can accurately measure the residual voltage of the cable under test by eliminating measurement errors caused by space charges generated in the lead cable.
［発明の構成］
上記目的を達成する本発明のケーブルの残留電
圧測定法は、上記のケーブルの残留電圧測定法に
おいて、リードケーブルとして中心導体の外側に
それぞれ絶縁層を介して中間遮蔽層と外部遮蔽層
とを設けた二重遮蔽ケーブルを用い、ケーブルの
導体と接続されたリードケーブルの中心導体を介
してケーブルの導体に直流電圧を前課電するとき
にはリードケーブルの中間遮蔽層を中心導体と同
電位になるように中心導体に接続し、前課電後の
ケーブル導体の接地時並びに接地開放後の回復電
圧の測定時には上記中間遮蔽層を接地し、リード
ケーブルの外部遮蔽層は常時接地しておくことを
特徴とするものである。[Structure of the Invention] The cable residual voltage measurement method of the present invention that achieves the above object is based on the cable residual voltage measurement method described above, in which an intermediate shielding layer and an external cable are connected to the outside of the center conductor as a lead cable via an insulating layer. When using a double-shielded cable with a shielding layer and pre-charging a DC voltage to the cable conductor via the center conductor of the lead cable connected to the cable conductor, the intermediate shielding layer of the lead cable should be used as the center conductor. Connect to the center conductor so that they have the same potential. When grounding the cable conductor after pre-charging and when measuring the recovery voltage after disconnecting the ground, the intermediate shielding layer is grounded, and the external shielding layer of the lead cable is always grounded. It is characterized by being kept.
［実施例及び作用の説明］
以下、実施例の図面により本発明の詳細を説明
する。[Description of Examples and Effects] The details of the present invention will be described below with reference to drawings of examples.
第１図において、１は被測定用ケーブルであ
る。Ａはケーブル導体１１に接続したリードケー
ブルであり、第２図に示すように、ケーブル導体
１１に接続された中心導体２１上に内部絶縁層２
１０（ゴムまたはプラスチツク）を介して中間遮
蔽層２２を設け、該中間遮蔽層２２上に外部絶縁
層２２０（ゴム又はプラスチツク）を介して外部
遮蔽層２３を設けてある。２３０はゴムまたはプ
ラスチツクのシースである。このリードケーブル
Ａの外部遮蔽層２３は常時接地されている。 In FIG. 1, 1 is a cable to be measured. A is a lead cable connected to the cable conductor 11, and as shown in FIG.
10 (rubber or plastic), and an outer shielding layer 23 is provided on the intermediate shielding layer 22 with an outer insulating layer 220 (rubber or plastic) interposed therebetween. 230 is a rubber or plastic sheath. The external shielding layer 23 of this lead cable A is always grounded.
DCは直流高圧電源であり、R1は充電抵抗、R2
は放電抵抗である。SW1、SW2、SW3並びにSW4
はスイツチである。Ｖは電位計である。リードケ
ーブルＡの中心導体２１と中間遮蔽層２２とはス
イツチSW1を介して接続しうるように結線されて
いる。ａ並びにｂは接点である。 DC is a direct current high voltage power supply, R 1 is a charging resistor, R 2
is the discharge resistance. SW 1 , SW 2 , SW 3 and SW 4
is a switch. V is an electrometer. The center conductor 21 of the lead cable A and the intermediate shielding layer 22 are connected to each other via a switch SW1 . a and b are contact points.
本発明を実施するには、まず、スイツチSW2を
開放した状態においてスイツチSW1をａ接点側に
接触させ、被測定ケーブル１のケーブル絶縁体に
直流高電圧DCを所定時間例えば10分間課電し、
ケーブル絶縁体内部に空間電荷を発生させる。こ
の場合、リードケーブルＡにおいては、中間遮蔽
層２２と中心導体２１とは互いに接続され同電位
であるから、これらの間の内部絶縁層２１０には
電界が作用せず、従つて、第３図に示すように内
部絶縁層２１０には空間電荷の発生はない。然
し、中間遮蔽層２２と外部遮蔽層２３との間には
電界が作用するので、外部絶縁層２２０には空間
電荷が発生する（第３図参照）。 To carry out the present invention, first, with switch SW 2 open, switch SW 1 is brought into contact with the a contact side, and high voltage DC is applied to the cable insulator of cable under test 1 for a predetermined period of time, for example, 10 minutes. death,
Generates a space charge inside the cable insulation. In this case, in the lead cable A, the intermediate shielding layer 22 and the center conductor 21 are connected to each other and have the same potential, so no electric field acts on the internal insulating layer 210 between them, and therefore, as shown in FIG. As shown in FIG. 2, no space charge is generated in the internal insulating layer 210. However, since an electric field acts between the intermediate shielding layer 22 and the outer shielding layer 23, space charges are generated in the outer insulating layer 220 (see FIG. 3).
このようにしてケーブル導体１１に直流高電圧
を前課電した後に、スイツチSW2を閉にし、放電
抵抗R2を介して接地し、更にその後SW3を閉に
し、ケーブル導体１１およびリードケーブルＡの
中心導体２１、中間遮蔽層２２を完全接地する。
この中間遮蔽層２２の接地後は、リードケーブル
の中間遮蔽層２２と外部遮蔽層２３とが共に接地
電位となるから、第３図に示すようにリードケー
ブルＡの外部絶縁層２２０に発生した上記の空間
電荷を完全に遮蔽できる。 After pre-charging the cable conductor 11 with a DC high voltage in this way, switch SW 2 is closed and grounded via the discharge resistor R 2 , and then SW 3 is closed and the cable conductor 11 and lead cable A The center conductor 21 and intermediate shielding layer 22 are completely grounded.
After the intermediate shielding layer 22 is grounded, both the intermediate shielding layer 22 and the outer shielding layer 23 of the lead cable are at ground potential, so that the above space charge can be completely shielded.
上記のように被測定ケーブル１のケーブル導体
１１を接地した後、所定時間例えば10秒経過後ス
イツチSW1をｂ接点側にし、更にSW4を開にして
ケーブル導体に徐々に回復してくる残留電圧を電
位計Ｖによつて測定する。この場合、前記リード
ケーブルの外部絶縁層の空間電荷は、中間遮蔽層
と外部遮蔽層との間にシールドしてあるから、上
記残留電圧の測定に影響を及ぼすことはない。 After grounding the cable conductor 11 of the cable under test 1 as described above, after a predetermined period of time, e.g. 10 seconds, switch SW 1 is set to the B contact side, and SW 4 is further opened to allow the residual residue to gradually recover on the cable conductor. The voltage is measured by an electrometer V. In this case, the space charge on the outer insulating layer of the lead cable is shielded between the intermediate shielding layer and the outer shielding layer, so it does not affect the measurement of the residual voltage.
なお、ケーブル終端部において空間電荷の発生
を防止するために、第１図において、点線で示す
ように、テーブル終端函にガード電極３，３を設
ける場合（例えば、半導電性テープまたは金属箔
の巻付けにより構成）、ガード電極３，３をリー
ドケーブルＡの中間遮蔽層２２に接続しておけ
ば、ガード電極３，３も上記スイツチSW1〜SW4
の操作によつて、リードケーブルの中間遮蔽層２
２と同様に中心導体２１との接続或は接地が行わ
れるので、作業上有利である。 In order to prevent the generation of space charges at the cable end, as shown by the dotted line in Fig. 1, guard electrodes 3, 3 are provided on the table end box (for example, using semiconductive tape or metal foil). If the guard electrodes 3, 3 are connected to the intermediate shielding layer 22 of the lead cable A, the guard electrodes 3, 3 can also be connected to the switches SW 1 to SW 4
The intermediate shielding layer 2 of the lead cable is
Since connection with the center conductor 21 or grounding is performed in the same way as in 2, it is advantageous in terms of work.
［発明の効果］
本発明に係るケーブルの残留電圧測定法によれ
ば、上述した通り、被測定ケーブルの導体への前
課電時にリードケーブルに発生した空間電荷をケ
ーブル導体の残留電圧に対して遮蔽でき、ケーブ
ル導体の残留電圧を正確に測定できる。[Effects of the Invention] According to the cable residual voltage measurement method according to the present invention, as described above, the space charge generated in the lead cable during pre-charging to the conductor of the cable to be measured is reduced to the residual voltage of the cable conductor. It can be shielded and the residual voltage in the cable conductor can be accurately measured.
第１図は本発明によるケーブルの残留電圧測定
の系統図であり、第２図は本発明において使用す
るリードケーブルを示す説明図、第３図は本発明
におけるリードケーブルの空間電荷の発生状態を
示す説明図である。
図において、１は被測定ケーブル、Ａはリード
ケーブル、２１は中心導体、２２は中間遮蔽層、
２３は外部遮蔽層、DCは直流高圧電源、Ｖは電
位計であり、SW1、SW2、SW3及びSW4はスイツ
チである。
Fig. 1 is a system diagram for measuring the residual voltage of a cable according to the present invention, Fig. 2 is an explanatory diagram showing a lead cable used in the present invention, and Fig. 3 shows the state of space charge generation in the lead cable according to the present invention. FIG. In the figure, 1 is the cable to be measured, A is the lead cable, 21 is the center conductor, 22 is the intermediate shielding layer,
23 is an external shielding layer, DC is a DC high voltage power supply, V is an electrometer, and SW 1 , SW 2 , SW 3 and SW 4 are switches.
Claims (1)
ードケーブルを介して直流電圧を前課電した後、
該導体を接地し、次いで該接地の開放後にケーブ
ルの導体に回復してくる電圧を上記リードケーブ
ルを介して測定するケーブルの残留電圧測定法に
おいて、上記リードケーブルとして中心導体の外
側にそれぞれ絶縁層を介して中間遮蔽層と外部遮
蔽層とを設けた二重遮蔽ケーブルを用い、ケーブ
ルの導体と接続されたリードケーブルの中心導体
を介してケーブルの導体に直流電圧を前課電する
ときにはリードケーブルの中間遮蔽層を中心導体
と同電位になるように中心導体に接続し、前課電
後のケーブル導体の接地時並びに接地開放後の回
復電圧の測定時には上記中間遮蔽層を接地し、リ
ードケーブルの外部遮蔽層は常時接地しておくこ
とを特徴とするケーブルの残留電圧測定法。1 After pre-applying a DC voltage to the conductor of the cable under test with the shielding layer grounded via the lead cable,
In a cable residual voltage measurement method in which the conductor is grounded and then the voltage restored to the conductor of the cable after the grounding is released is measured via the lead cable, an insulating layer is provided on the outside of the center conductor as the lead cable. When using a double-shielded cable with an intermediate shielding layer and an external shielding layer provided through the lead cable, the conductor of the cable is pre-charged with a DC voltage through the center conductor of the lead cable connected to the conductor of the cable. Connect the intermediate shielding layer to the center conductor so that it has the same potential as the center conductor, and connect the intermediate shielding layer to the center conductor when grounding the cable conductor after pre-charging and when measuring the recovery voltage after disconnecting the ground. A cable residual voltage measurement method characterized by keeping the external shielding layer grounded at all times.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP11910085A JPS61292074A (en) | 1985-05-31 | 1985-05-31 | Method for measuring residual voltage of cable |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP11910085A JPS61292074A (en) | 1985-05-31 | 1985-05-31 | Method for measuring residual voltage of cable |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS61292074A JPS61292074A (en) | 1986-12-22 |
| JPH0525074B2 true JPH0525074B2 (en) | 1993-04-09 |
Family
ID=14752905
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP11910085A Granted JPS61292074A (en) | 1985-05-31 | 1985-05-31 | Method for measuring residual voltage of cable |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS61292074A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP6230367B2 (en) * | 2013-10-17 | 2017-11-15 | 古河電気工業株式会社 | Calibration sample for space charge measurement and calibration method using the same |
-
1985
- 1985-05-31 JP JP11910085A patent/JPS61292074A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS61292074A (en) | 1986-12-22 |
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