JP2001116789A - Method for measuring residual charge of insulator and method for diagnosing insulation deterioration of power cable using it - Google Patents
Method for measuring residual charge of insulator and method for diagnosing insulation deterioration of power cable using itInfo
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- JP2001116789A JP2001116789A JP29906199A JP29906199A JP2001116789A JP 2001116789 A JP2001116789 A JP 2001116789A JP 29906199 A JP29906199 A JP 29906199A JP 29906199 A JP29906199 A JP 29906199A JP 2001116789 A JP2001116789 A JP 2001116789A
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Abstract
Description
【０００１】[0001]
【発明が属する技術分野】本発明は、各種絶縁体に蓄積
した空間電荷を検出する測定方法に関し、特に電力ケー
ブルの絶縁劣化診断等に好適に供用できる空間電荷の測
定方法に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a measuring method for detecting space charges accumulated in various insulators, and more particularly to a method for measuring space charges which can be suitably used for diagnosis of insulation deterioration of a power cable.
【０００２】[0002]
【発明の背景】架橋ポリエチレン絶縁電力ケーブル（Ｃ
Ｖケーブル）などのゴム・プラスチック絶縁ケーブルの
長期寿命を決定する重要な劣化要因として、水トリー劣
化が知られている。この水トリー劣化を検出する手法の
一つに残留電荷を検出する方法がある。この方法は、絶
縁体試料に直流高電圧を印加し、その後接地して直流印
加電圧を除去し、接地期間中に回復してくる直流電荷
（残留電荷）を測定する方法である。BACKGROUND OF THE INVENTION Crosslinked polyethylene insulated power cables (C
Water tree deterioration is known as an important deterioration factor that determines the long-term life of a rubber / plastic insulated cable such as a V cable. One of the methods of detecting the water tree deterioration is a method of detecting a residual charge. This method is a method in which a high DC voltage is applied to an insulator sample, which is then grounded to remove the DC applied voltage, and the DC charge (residual charge) recovered during the grounding period is measured.
【０００３】従来の残留電荷検出方法としては、図１
(ａ)、(ｂ)に示す方法が知られている。図１(ａ)は電流
測定による方法であり、直流高圧課電装置２０による直
流課電後の接地時の瞬時放電電流（絶縁体の静電容量を
充電していた電極上電荷の放電による電流）が消滅後
に、接地回路に１〜１０ｋΩ程度の電流検出抵抗６ａを
挿入して、試料１の放電吸収電流（絶縁体中の空間電荷
の移動・消滅過程によって生じる電流成分）Ｉｄ(ｔ)＝
Ｖｄ(ｔ)／Ｒｄを検出(実際は直流電圧計５ａで検出)
し、その時間積分値を残留電荷Ｑ(ｔ)として求める。[0003] As a conventional residual charge detection method, FIG.
The methods shown in (a) and (b) are known. FIG. 1A shows a method based on current measurement, in which an instantaneous discharge current at the time of grounding after DC power is applied by the DC high-voltage power applying device 20 (current due to discharge of electric charge on the electrode that has charged the capacitance of the insulator). ) Disappears, a current detection resistor 6a of about 1 to 10 kΩ is inserted into the ground circuit, and the discharge absorption current of the sample 1 (current component generated by the process of moving and eliminating space charge in the insulator) Id (t) =
Vd (t) / Rd detected (actually detected by DC voltmeter 5a)
Then, the time integration value is obtained as a residual charge Q (t).
【０００４】また図１(ｂ)は電圧測定による方法であ
り、直流課電後に一旦接地して瞬時放電電流消滅後に、
入力抵抗の高い直流電圧計５ｂと電荷測定用のコンデン
サ６ｂを絶縁体電極間に並列接続して、試料電極間に回
復してくる直流電圧Ｖｄ(ｔ)を検出する。残留電荷はＱ
(ｔ)≡(Ｃｄ＋Ｃｘ)Ｖｄ(ｔ)として求める。なお、図１
(ａ)、(ｂ)において、ＣｘとＣｄは各々試料１とコンデ
ンサ６ｂの静電容量、３０は放電抵抗、４０は切り替え
スイッチ、７ｂは測定回路短絡スイッチをそれぞれ示し
ている。FIG. 1 (b) shows a method based on voltage measurement.
A DC voltmeter 5b having a high input resistance and a capacitor 6b for charge measurement are connected in parallel between the insulator electrodes, and the DC voltage Vd (t) recovered between the sample electrodes is detected. The residual charge is Q
(t) ≡ (Cd + Cx) Vd (t). FIG.
3A and 3B, Cx and Cd denote capacitances of the sample 1 and the capacitor 6b, 30 denotes a discharge resistor, 40 denotes a changeover switch, and 7b denotes a measurement circuit short-circuit switch.
【０００５】これら従来の図１(ａ)、(ｂ)に示した方法
で検出される残留電荷の発生源は、直流課電によって絶
縁体中に蓄積していた空間電荷λであるが、全ての空間
電荷が残留電荷として検出されるものではない。例え
ば、図１(ａ)の電流測定回路において、絶縁体中に空間
電荷λが蓄積されていたとしても、この電荷が静止して
いる限り測定回路には電流Iｄ(ｔ)が流れない。また同
様に、図１(ｂ)の電圧測定回路においても、空間電荷λ
が電極方向に変位しなければ直流電圧Ｖｄ(ｔ)は測定開
始時の初期値Ｖｄ(０)＝０から変化しない。すなわち、
従来の方法で検出される残留電荷は、直流印加電圧除去
後の測定期間中に、試料絶縁体内部で空間的または時間
的に変化する空間電荷成分を検出していることになる。The source of the residual charge detected by the conventional method shown in FIGS. 1 (a) and 1 (b) is the space charge λ accumulated in the insulator due to the DC application. Are not detected as residual charges. For example, in the current measuring circuit shown in FIG. 1A, even if the space charge λ is accumulated in the insulator, the current Id (t) does not flow through the measuring circuit as long as the charge is stationary. Similarly, in the voltage measuring circuit of FIG.
Is not displaced in the electrode direction, the DC voltage Vd (t) does not change from the initial value Vd (0) = 0 at the start of measurement. That is,
The residual charge detected by the conventional method means that a space charge component that changes spatially or temporally inside the sample insulator is detected during the measurement period after the removal of the DC applied voltage.
【０００６】直流高電界印加によって絶縁体中に蓄積す
る空間電荷としては、導電率と誘電率の不均質な界面に
蓄積する界面電荷や電極から注入される電荷などがあ
る。これら空間電荷が直流印加電圧除去後（すなわち接
地後）に絶縁体中に残留すると、印加電圧を取り去った
後にも空間電荷自身が絶縁体内部に電界を形成する。こ
の空間電荷電界の作用によって、空間電荷は接地時に直
流印加前の状態に戻るように移動・減衰する。従来手法
による測定では、この空間電荷消滅時点で残留電荷が最
大値に飽和する。すなわち、残留電荷Ｑ(ｔ)は、測定開
始後のＱ(０)＝０からある飽和値Ｑ(tmax)＝Ｑmaxに回
復する時間特性を有する。[0006] Space charges accumulated in an insulator by application of a DC high electric field include interface charges accumulated at an interface having non-uniform conductivity and dielectric constant, and charges injected from an electrode. If these space charges remain in the insulator after removing the applied DC voltage (that is, after grounding), the space charges themselves form an electric field inside the insulator even after removing the applied voltage. By the action of the space charge electric field, the space charge moves and attenuates so as to return to the state before DC application at the time of grounding. In the measurement by the conventional method, the residual charge saturates to the maximum value when the space charge disappears. That is, the residual charge Q (t) has a time characteristic of recovering from Q (0) = 0 after the start of measurement to a certain saturation value Q (tmax) = Qmax.
【０００７】本発明者らの研究によれば、高電圧印加に
よる絶縁体中での空間電荷の発生過程と印加電圧除去後
の空間電荷の消滅過程は一般的に非可逆な傾向があり、
多くの場合、発生よりも消滅に要する時間が長い。例え
ば、本発明者らの水トリー劣化ＣＶケーブルを用いた実
験結果では、１分未満の直流課電で空間電荷を形成させ
た場合でも、直流印加電圧除去後に観測される残留電荷
は２４時間以上経過しても飽和に達しない。このよう
に、従来の図１(ａ)、(ｂ)の測定方法では残留電荷が飽
和値に達するまでの時間が長いことと、実用的な短時間
の測定では大きな残留電荷が得られないことなどから、
類似の誤差信号、例えば、直流課電によって電極間の絶
縁体表面に帯電した電荷による残留電荷との区別が難し
いという問題などがあった。従って、この従来法をＣＶ
ケーブル絶縁体の水トリー劣化診断に適用しても、信頼
性の高い診断結果は得られなかった。According to the study of the present inventors, the process of generating space charge in an insulator by applying a high voltage and the process of eliminating space charge after removing an applied voltage generally tend to be irreversible.
In many cases, it takes longer to annihilate than to occur. For example, according to the experimental results of the present inventors using a water tree-degraded CV cable, even when a space charge is formed by applying a DC voltage of less than 1 minute, the residual charge observed after removing the DC voltage is more than 24 hours. It does not reach saturation even after passing. As described above, in the conventional measurement method of FIGS. 1A and 1B, the time until the residual charge reaches the saturation value is long, and a large residual charge cannot be obtained in a practical short-time measurement. From
There has been a problem that it is difficult to distinguish a similar error signal, for example, from a residual charge due to a charge on the insulator surface between the electrodes due to DC application. Therefore, this conventional method is referred to as CV
Even when applied to water tree deterioration diagnosis of cable insulation, highly reliable diagnosis results were not obtained.
【０００８】この問題を解決する方法として、接地後の
残留電荷測定時に交流電圧を印加する方法が提案され
た。つまり、接地時の空間電荷電界だけでは電荷の移動
が遅いので、交流電界を外部から印加して試料内部の空
間電荷電界に重畳させて、電荷の移動と減衰時間を速め
る方法である。この交流電圧を印加する測定方法におい
ても、残留電荷の検出方法としては電流測定と電圧測定
による方法がある。図１(ｃ)は、本発明者らが先に提案
した交流課電下で残留電荷を測定する回路例である。こ
のような測定回路において、直流課電・接地後に試料１
を交流高電圧発生装置８ｃに接続し、交流課電開始の直
前に直流電荷検出用コンデンサ６ｃの電極間短絡用スイ
ッチ７ｃを開放し、交流課電下でコンデンサ電極間に現
れる直流電圧成分Ｖｄ(ｔ)を検出して、コンデンサ６ｃ
と試料１の合計の静電容量(Ｃｄ＋Ｃｘ)とＶｄ(ｔ)の積
から残留電荷Ｑ(ｔ)≡(Ｃｄ＋Ｃｘ）Ｖｄを算出するも
のである。As a method for solving this problem, there has been proposed a method of applying an AC voltage when measuring the residual charge after grounding. That is, since the movement of charges is slow only by the space charge electric field at the time of grounding, an AC electric field is applied from the outside and superimposed on the space charge electric field inside the sample to speed up the movement and decay time of the charges. In the measurement method of applying the AC voltage, the method of detecting the residual charge includes a method of measuring current and a method of measuring voltage. FIG. 1 (c) is an example of a circuit for measuring the residual charge under the AC application proposed by the present inventors. In such a measurement circuit, the sample 1
Is connected to an AC high voltage generator 8c, the switch 7c for short-circuiting between the electrodes of the DC charge detection capacitor 6c is opened immediately before the start of AC power application, and the DC voltage component Vd ( t) is detected and the capacitor 6c is detected.
The residual charge Q (t) ≡ (Cd + Cx) Vd is calculated from the product of the total capacitance (Cd + Cx) of the sample 1 and Vd (t).
【０００９】従来の残留電荷法で交流電圧を使用する理
由は、印加電圧として直流成分を含まない点にある。す
なわち、もしも印加電圧中に直流成分が含まれている
と、試料の静電容量を充電する直流電荷が電極上に発生
して残留電荷と区別できなくなる問題が生じてしまうか
らである。また、正または負の単極性電圧を印加する
と、その印加電圧が直流課電によって生じた電荷とは別
の空間電荷を形成させる可能性があり、直流課電によっ
て形成されていた空間電荷を検出する目的から見ると好
ましくないと考えられていた。そこで、直流課電後の残
留電荷測定時に印加する電圧としては正負に振動する交
流電圧を必要とし、また、交流電圧の印加方法として
も、直流成分の発生を抑えるために、電圧の突印（又は
遮断）を避けて、電圧を零から所定の大きさまで連続的
に昇圧又は降圧する方法が採用された。The reason for using the AC voltage in the conventional residual charge method is that the applied voltage does not include a DC component. That is, if a DC component is contained in the applied voltage, a DC charge for charging the capacitance of the sample is generated on the electrode, which causes a problem that the DC charge cannot be distinguished from the residual charge. In addition, when a positive or negative unipolar voltage is applied, the applied voltage may form a space charge different from the charge generated by the DC charge, and the space charge formed by the DC charge is detected. It was considered unfavorable for the purpose of doing. Therefore, an AC voltage that oscillates positively and negatively is required as a voltage to be applied at the time of measuring the residual charge after the DC application, and a method of applying the AC voltage is to suppress the generation of the DC component by using a voltage stamp ( In other words, a method of continuously raising or lowering the voltage from zero to a predetermined value while avoiding the interruption is adopted.
【００１０】図２は、交流課電を行わない図１(ａ)、
(ｂ)による残留電荷測定と、交流課電下で残留電荷測定
を行う図１(ｃ)による残留電荷法の測定結果を模式的に
比較したものである。図に示すように、直流課電・接地
後の残留電荷測定時に交流課電を行うと、水トリー劣化
ケーブルの残留電荷の緩和時間が著しく速くなる。例え
ば、交流印加電圧の波高値を零から直流印加電圧値以上
程度までに昇圧すると、この昇圧の短時間中に残留電荷
は最大値までに飽和する。また、図２の例では、交流電
圧の印加方法として、電圧を短時間で最高値までに昇圧
後に、最高値に保持することなく、直ちに零まで降下さ
せる課電方法を示している。この短時間の交流昇降法を
採用すると、交流印加中に静電容量を充電する直流誤差
電荷が現れてもこれを無視して、交流電圧印加前後での
残留電荷の変化分を読み取れば良い。従って、図１(ｃ)
に示す交流印加を併用する測定回路と、図２の交流短時
間課電方法を採用することで、図１(ａ)、(ｂ)に示す方
法に比べて測定の信頼性が著しく改善されるのである。FIG. 2 is a circuit diagram of FIG.
FIG. 1B is a schematic comparison of the measurement results of the residual charge measurement shown in FIG. 1B and the measurement results of the residual charge method shown in FIG. As shown in the figure, when the AC charging is performed at the time of measuring the residual charge after the DC charging and grounding, the relaxation time of the residual charge of the water tree deteriorated cable is significantly shortened. For example, when the peak value of the AC applied voltage is raised from zero to about the DC applied voltage value or more, the residual charge is saturated to the maximum value in a short time of this boosting. Further, in the example of FIG. 2, as an application method of the AC voltage, a power application method in which the voltage is boosted to the maximum value in a short time and then immediately dropped to zero without holding at the maximum value is shown. When this short-time AC raising / lowering method is adopted, even if a DC error charge for charging the capacitance during the AC application appears, the DC error charge may be ignored and the change in the residual charge before and after the AC voltage application may be read. Therefore, FIG.
2 and the short-time AC application method shown in FIG. 2 significantly improve the reliability of the measurement as compared with the method shown in FIGS. 1 (a) and 1 (b). It is.
【００１１】しかしながら、この残留電荷法による劣化
診断を実際のケーブル線路に適用するためには、線路の
静電容量を充電可能な大容量の交流課電装置が必要にな
る。この場合、測定装置が大型化して重量も重くなり、
狭隘な場所での測定に問題が生じる。装置の大型化・重
量化を軽減する方法としては、図１(ｃ)の交流電圧の印
加時間を可能な限り短くして小型の交流課電装置で電流
容量を確保する方法が考えられる。また、その極限とし
ては、交流に代替できる電圧波形として、両極性に振動
する減衰振動波電圧などの利用が考えられる。しかし、
いずれの場合も印加電圧波形の制御が複雑になる問題が
ある。However, in order to apply the deterioration diagnosis by the residual charge method to an actual cable line, a large-capacity AC charging device capable of charging the capacitance of the line is required. In this case, the measuring device becomes large and heavy,
Problems arise in measurements in tight spaces. As a method of reducing the size and weight of the device, a method of shortening the AC voltage application time as shown in FIG. 1C as much as possible and securing the current capacity with a small AC power supply device is considered. As the limit, use of an attenuated oscillating wave voltage that oscillates in both polarities can be considered as a voltage waveform that can be substituted for AC. But,
In either case, there is a problem that the control of the applied voltage waveform becomes complicated.
【００１２】[0012]
【発明の目的】従って本発明は、測定のための装置の重
量化と大型化の原因になる交流電圧や、波形調整が複雑
な減衰振動波電圧を用いずに、信頼性のある残留電荷測
定を可能にする方法を提供することを目的とする。前述
のように、従来の残留電荷測定手法は、電圧印加による
空間電荷の蓄積過程と印加電圧除去後の消滅過程の非可
逆性が十分に考慮されていない。従って、直流電圧印加
の短時間で形成された空間電荷が接地状態下で消滅する
には長時間を要するにもかかわらず、この移動・消滅過
程に基づく信号を検出しようとしている点が問題の所在
である。SUMMARY OF THE INVENTION Accordingly, the present invention provides a reliable residual charge measurement without using an AC voltage that causes the measurement apparatus to be heavy and large, and an attenuated oscillating wave voltage that requires complicated waveform adjustment. The purpose is to provide a method that enables As described above, the conventional residual charge measurement method does not sufficiently consider the irreversibility of the space charge accumulation process due to voltage application and the disappearance process after removal of the applied voltage. Therefore, despite the fact that it takes a long time for space charges formed in a short period of time when a DC voltage is applied to disappear under a grounded state, it is trying to detect a signal based on this movement / elimination process. is there.
【００１３】本発明では、従来の残留電荷測定の概念を
基本的に転換し、印加電圧除去状態下では容易に移動・
消滅しない空間電荷成分を残留電荷として検出する。つ
まり、印加電圧除去後も空間電荷が容易に消滅しないの
であれば、試料内部で空間電荷が測定期間中に近似的に
静止している状態を残留電荷として検出すれば良しとの
観点に立脚している。かかる観点によれば、静止した電
荷による信号を検出するゆえに、わざわざ交流印加を行
って電荷の移動・消滅を速める必要が無くなるのであ
る。According to the present invention, the concept of the conventional residual charge measurement is basically changed, and the movable charge can be easily moved / removed when the applied voltage is removed.
Space charge components that do not disappear are detected as residual charges. In other words, if the space charge does not disappear easily even after the applied voltage is removed, it is better to detect the state in which the space charge is approximately stationary during the measurement period as the residual charge inside the sample. ing. According to this viewpoint, since the signal based on the stationary charge is detected, it is not necessary to perform the AC application to accelerate the movement and disappearance of the charge.
【００１４】[0014]
【課題を解決するための手段】本発明の絶縁体の残留電
荷測定方法は、試料絶縁体とコンデンサの直列接続体に
正又は負の単極性高電圧Ｖｏを印加し、このときのコン
デンサ分担電圧を直流電圧計で観測し、パルス電圧印加
後に残留するコンデンサ分担電圧に基づいて試料絶縁体
中に蓄積した電荷を検出することを特徴とするものであ
る。According to the present invention, there is provided a method for measuring the residual electric charge of an insulator, comprising applying a positive or negative unipolar high voltage Vo to a series connection of a sample insulator and a capacitor, Is observed with a DC voltmeter, and the electric charge accumulated in the sample insulator is detected based on the capacitor shared voltage remaining after application of the pulse voltage.
【００１５】また本発明の他の測定方法は、上記した測
定をなした後に、一旦コンデンサの電極間を短絡し、そ
の後短絡を開放した状態で、最初に印加した上記単極性
高電圧Vｏと逆極性の電圧−Vｏをさらに印加し、次いで
このときのコンデンサ分担電圧を直流電圧計で観測し、
パルス電圧印加後に残留するコンデンサ分担電圧に基づ
いて試料絶縁体中に蓄積した電荷を検出することを特徴
とするものである。In another measurement method of the present invention, after performing the above-described measurement, the electrodes of the capacitor are short-circuited once, and then the short-circuit is opened, and the reverse is applied to the unipolar high voltage Vo applied first. Polarity voltage -Vo is further applied, and then the capacitor sharing voltage at this time is observed with a DC voltmeter,
It is characterized in that charges accumulated in the sample insulator are detected based on a capacitor sharing voltage remaining after application of the pulse voltage.
【００１６】さらに、本発明は電力ケーブルの絶縁劣化
診断に好適に適用でき、該診断方法は、上記した残留電
荷測定方法において、試料絶縁体を電力ケーブルの絶縁
層とし、当該測定により得られた残留電荷に基づいて前
記絶縁層の絶縁劣化度合いを診断することを特徴とする
ものである。Further, the present invention can be suitably applied to insulation deterioration diagnosis of a power cable, and the diagnosis method is obtained by the above-described residual charge measurement method, wherein a sample insulator is used as an insulation layer of a power cable and the measurement is performed. The degree of insulation deterioration of the insulating layer is diagnosed based on the residual charge.
【００１７】[0017]
【作用】以下、本発明の測定原理について説明する。な
お以後の説明では、簡単のために、高電圧印加によって
平行平板電極内の絶縁体中に空間電荷が発生した場合を
例に挙げて説明する。図３(ａ)において、１は平行平板
電極に挟まれた試料絶縁体、２は単極性の高電圧発生装
置、３は電荷測定用のコンデンサである。試料絶縁体１
と高電圧発生装置２を直列に接続した図中点ＡＢ間に単
極性電圧Ｖｏを印加したときに、試料１のＡ側電極から
絶縁体中に電荷が注入された場合を考える。ここに、Ｃ
ｘ＝εＳ／ｄは試料１の静電容量、εは絶縁体の誘電
率、ｄとＳはＣｘの絶縁体厚さと電極面積、Ｃｄは電荷
検出用コンデンサ３の静電容量とし、またＶｘとＶｄ
は、試料絶縁体１とコンデンサ３との電極間電圧であ
る。４はコンデンサ１の電極間を開閉するスイッチであ
り、該スイッチ４は電圧Ｖｏを印加している期間中は常
に開放されている。また、簡単のために高電圧発生装置
２の内部抵抗は零と扱うものとする。The principle of measurement according to the present invention will be described below. In the following description, for the sake of simplicity, a case where a space charge is generated in an insulator in a parallel plate electrode by application of a high voltage will be described as an example. In FIG. 3A, reference numeral 1 denotes a sample insulator sandwiched between parallel plate electrodes, 2 denotes a unipolar high voltage generator, and 3 denotes a capacitor for measuring electric charge. Sample insulator 1
A case is considered in which, when a unipolar voltage Vo is applied between points AB in the figure where the high voltage generator 2 and the high voltage generator 2 are connected in series, charges are injected into the insulator from the A-side electrode of the sample 1. Where C
x = εS / d is the capacitance of the sample 1, ε is the dielectric constant of the insulator, d and S are the insulator thickness and electrode area of Cx, Cd is the capacitance of the charge detection capacitor 3, and Vx and Vd
Is the voltage between the electrodes of the sample insulator 1 and the capacitor 3. Reference numeral 4 denotes a switch for opening and closing the electrodes of the capacitor 1, and the switch 4 is always open during a period in which the voltage Vo is applied. For simplicity, the internal resistance of the high voltage generator 2 is assumed to be zero.
【００１８】さて、図３(ａ)に示した回路図において、
ＡＢ間に電圧Ｖｏを印加すると、試料１とコンデンサ３
の電極上には電荷が誘導される。いま、試料のＡ側電極
から深さｄ１面に電荷が注入して空間電荷λが形成され
た状態で、コンデンサ３の電極間に発生する電圧Ｖｄを
考える。試料１の点Ｍ側電極に電荷ｑが誘導された場合
には、コンデンサ３のＭ側電極の内部表面には逆符号の
電荷−ｑが誘導される。また、試料１の電極外部を囲む
閉曲面とコンデンサ３の電極外部を囲む閉曲面には外向
きの電束が現れない。つまり、これら電極内部に存在す
る電荷の合計は零である。また、ＡＢ間の印加電圧Ｖｏ
は、試料１の電極間電圧Ｖｘと電荷検出用コンデンサ３
の電極間電圧Ｖｄの和に等しい。Now, in the circuit diagram shown in FIG.
When a voltage Vo is applied between AB, the sample 1 and the capacitor 3
An electric charge is induced on the electrodes. Now, consider a voltage Vd generated between the electrodes of the capacitor 3 in a state in which charges are injected from the A-side electrode of the sample to the surface at the depth d1 to form space charges λ. When the electric charge q is induced to the point M-side electrode of the sample 1, the electric charge -q having the opposite sign is induced to the inner surface of the M-side electrode of the capacitor 3. Further, no outward electric flux appears on the closed curved surface surrounding the outside of the electrode of the sample 1 and the closed curved surface surrounding the outside of the electrode of the capacitor 3. That is, the sum of the charges existing inside these electrodes is zero. Further, the applied voltage Vo between A and B is
Are the voltage Vx between the electrodes of the sample 1 and the capacitor 3 for charge detection.
Is equal to the sum of the inter-electrode voltages Vd.
【００１９】以上の知見に基づいてＶｄを求める、 Ｖｄ＝（ＣｘＶｏ＋λｄ１／ｄ）／(Ｃｘ＋Ｃｄ) … (１) となる。これがＶｏが印加された状態下で電荷検出用コ
ンデンサ３の電極間に観測される電圧である。Vd is obtained based on the above knowledge. Vd = (CxVo + λd1 / d) / (Cx + Cd) (1) This is the voltage observed between the electrodes of the charge detection capacitor 3 when Vo is applied.
【００２０】上記(１)式においてＶｏ＝０とすると、印
加電圧Ｖｏが零までに消滅した後の状態でコンデンサ１
の電極間に観測される電圧が得られる。本発明の請求項
１に記載の方法では、この印加電圧消滅後のＶｄを検出
して静電容量(Ｃｘ＋Ｃｄ)を掛け合せた値を残留電荷と
している。すなわち、単極性電圧Ｖｏの印加によって絶
縁体中に空間電荷λが蓄積し、Ｖｏが零に消滅後も絶縁
体中で移動・消滅しなかった場合には、次の(２)式で表
される残留電荷Ｑが検出される。 Ｑ≡(Ｃｘ＋Ｃｄ)Ｖｄ＝λｄ１／ｄ （Ｖｏが零に消滅後の場合） … (２) つまり、空間電荷λが試料１の絶縁体中のｄ１面に残留
していた場合には、印加電圧Ｖｏが零に消滅後も直流電
荷検出用コンデンサ３の電極間電圧Ｖｄは零にならな
い。このＶｄに静電容量(Ｃｘ＋Ｃｄ)を掛け合わせて得
た残留電荷Ｑは、試料内部に残留している空間電荷の大
きさλと、その存在しているポイントの深さｄ１に比例
する。Assuming that Vo = 0 in the above equation (1), the state of the capacitor 1 after the applied voltage Vo has disappeared to zero is obtained.
The voltage observed between the electrodes is obtained. In the method according to the first aspect of the present invention, the value obtained by detecting Vd after the disappearance of the applied voltage and multiplying the detected value by the capacitance (Cx + Cd) is defined as the residual charge. That is, when the space charge λ accumulates in the insulator due to the application of the unipolar voltage Vo and does not move or disappear in the insulator even after Vo disappears to zero, it is expressed by the following equation (2). Residual charge Q is detected. Q≡ (Cx + Cd) Vd = λd1 / d (after Vo has disappeared to zero) (2) That is, when the space charge λ remains on the d1 surface in the insulator of the sample 1, the applied voltage Even after Vo disappears to zero, the voltage Vd between the electrodes of the DC charge detection capacitor 3 does not become zero. The residual charge Q obtained by multiplying this Vd by the capacitance (Cx + Cd) is proportional to the size λ of the space charge remaining inside the sample and the depth d1 of the existing point.
【００２１】次に、本発明と従来法の違いを説明する。
本発明が検出しようとする残留電荷は、従来の電流測定
手法では検出できない。なぜならば、本発明は、印加電
圧消滅後も測定期間中で近似的に静止状態に近い電荷を
検出しようとしており、電荷が静止していれば電流が流
れないからである。Next, the difference between the present invention and the conventional method will be described.
The residual charge that is to be detected by the present invention cannot be detected by the conventional current measurement technique. The reason for this is that the present invention attempts to detect a charge that is approximately in a stationary state during the measurement period even after the applied voltage has disappeared, and no current flows if the charge is stationary.
【００２２】また、本発明の方法を従来の電圧測定によ
る手法に比較すると、本発明の方法では、印加電圧Ｖｏ
が消滅後に電荷検出用コンデンサ３の電極間をスイッチ
４で短絡しない点が従来の方法と異なっている。従来法
では印加電圧を除去するために一旦試料１の電極間を接
地してから残留電荷測定を開始する。従来法の操作を図
３(ａ)に当てはめると、測定開始時の初期条件として
は、試料１の電極上にはＶｘ＝０となるように、またコ
ンデンサ３の電極上にはＶｄ＝０となるように電荷が誘
導されている。試料中に空間電荷λが深さｄ１面に蓄積
している場合には、試料１の電極上には電荷が誘導され
ているが、コンデンサ３には空間電荷が存在していない
ので、その電極上には電荷が誘導されない。これが、従
来法による残留電荷測定時の初期条件であり、外部に電
位差が現れない状態Ｖｘ＝−Ｖｄ＝０を形成している。
従って、従来法では空間電荷λが空間的に移動するか、
あるいは時間的に大きさが変化するなどして電極上の誘
導電荷との平衡条件が崩れて初めてＶｘ＝−Ｖｄ≠０な
る信号が検出されることになる。以上にて本発明の請求
項１記載の発明と従来法の差異を説明した。In addition, comparing the method of the present invention with the conventional voltage measurement method, the method of the present invention shows that the applied voltage Vo
Is different from the conventional method in that the electrodes of the charge detection capacitor 3 are not short-circuited by the switch 4 after the disappearance of. In the conventional method, the residual charge measurement is started after the electrodes of the sample 1 are once grounded in order to remove the applied voltage. When the operation of the conventional method is applied to FIG. 3A, the initial conditions at the start of the measurement are such that Vx = 0 on the electrode of the sample 1 and Vd = 0 on the electrode of the capacitor 3. The charge is induced to be When the space charge λ accumulates on the surface of the sample at the depth d1 in the sample, the charge is induced on the electrode of the sample 1, but there is no space charge in the capacitor 3; No charge is induced on top. This is the initial condition at the time of the residual charge measurement according to the conventional method, and forms the state Vx = −Vd = 0 where no potential difference appears outside.
Therefore, in the conventional method, the space charge λ moves spatially,
Alternatively, a signal of Vx = −Vd ≠ 0 is detected only when the condition of equilibrium with the induced charge on the electrode is broken due to a change in size with time or the like. The difference between the first aspect of the present invention and the conventional method has been described above.
【００２３】請求項２発明の方法は、従来法と請求項１
の組み合わせによる方法であり、以下に説明する。図３
(ａ)において、まず最初に、従来法と同様にして、単極
性の電圧＋Ｖｏを試料１に印加後にスイッチ４を閉じて
試料１と電荷測定用コンデンサ３の電極間を短絡する。
前述のように、電圧Ｖｏの印加によって試料のＡ側電極
から絶縁体の深さｄ１に空間電荷＋λが注入して蓄積さ
れると、スイッチ４の短絡によって試料１の電極上には
電荷が誘導される。次に、スイッチ４を開放して＋Ｖｏ
と逆極性の単極性電圧−ＶｏをＡＢ間に印加すると、こ
の−Ｖｏによる試料内部の電界は先の＋Ｖｏ印加による
空間電荷＋λを試料のＡ側電極に戻して空間電荷＋λを
消滅させるように作用する。The method of the present invention is the same as the conventional method.
, And will be described below. FIG.
In (a), first, a unipolar voltage + Vo is applied to the sample 1 and the switch 4 is closed to short-circuit the electrodes of the sample 1 and the capacitor 3 for charge measurement in the same manner as in the conventional method.
As described above, when the space charge + λ is injected from the A-side electrode of the sample to the depth d1 of the insulator and accumulated by application of the voltage Vo, a charge is induced on the electrode of the sample 1 due to the short circuit of the switch 4. Is done. Next, switch 4 is opened and + Vo
When a unipolar voltage -Vo of the opposite polarity to-is applied across AB, the electric field inside the sample due to -Vo returns the space charge + [lambda] due to the previous + Vo application to the A-side electrode of the sample so that the space charge + [lambda] disappears. Works.
【００２４】いま、簡単のために、逆極性電圧−Ｖｏの
印加によって新たな空間電荷が形成されずに最初の＋Ｖ
ｏ印加によって形成されていた空間電荷＋λがＡ側電極
側にΔｄだけ戻った場合を考えると、−Ｖｏが零に減衰
後には、空間電荷の移動によって、試料１およびコンデ
ンサ３の電極上には電荷が誘導されている。この結果、
電荷検出用コンデンサ３の電極間には、 Ｖｄ＝−△ｑ／Ｃｄ＝−λｄ１／ｄ×１／(Ｃｘ＋Ｃｄ) なる電圧が発生し、 残留電荷Ｑ＝(Ｃｘ＋Ｃｄ)Ｖｄ＝−λｄ１／ｄ が検出される。For the sake of simplicity, a new space charge is not formed by application of the reverse polarity voltage -Vo, and the first + V
Considering the case where the space charge + λ formed by the application of o returns to the A-side electrode side by Δd, after −Vo has decayed to zero, the space charge moves to the electrodes of the sample 1 and the capacitor 3 due to the movement of the space charge. A charge has been induced. As a result,
A voltage of Vd = − △ q / Cd = −λd1 / d × 1 / (Cx + Cd) is generated between the electrodes of the charge detection capacitor 3, and the residual charge Q = (Cx + Cd) Vd = −λd1 / d is detected. Is done.
【００２５】次に、逆極性電圧−Ｖｏ'の印加によっ
て、最初の＋Ｖｏ印加による空間電荷＋λが試料のＡ側
電極まで戻って消滅すると同時に、新たに逆極性の空間
電荷−λ'が試料のＡ側電極からｄ１面に注入され、こ
れが−Ｖｏが零に減衰後も残留した場合を考えると、逆
極性の印加電圧−Ｖｏが減衰後には、電荷検出用コンデ
ンサ３の電極間電圧は Ｖｄ＝−(λｄ１／ｄ＋λ'ｄ１／ｄ）／(Ｃｘ＋Ｃｄ) となり、残留電荷は Ｑ＝(Ｃｘ＋Ｃｄ)Ｖｄ＝−(λｄ１／ｄ＋λ'ｄ１／ｄ） として検出される。すなわち、後から印加する逆極性電
圧−Ｖｏ'が先に形成されていた空間電荷＋λの消滅と
新たな空間電荷−λ'の形成に十分な時間幅を有すれば
これら単極性電圧を個々に印加した場合に得られる残留
電荷の和が検出されることになる。Next, by the application of the reverse polarity voltage -Vo ', the space charge + λ due to the first + Vo application returns to the A-side electrode of the sample and disappears, and at the same time, the space charge -λ' of the opposite polarity is newly applied to the sample. Considering the case where the voltage is injected from the A-side electrode to the d1 surface and this remains after -Vo has been attenuated to zero, the voltage between the electrodes of the charge detection capacitor 3 is Vd = − (Λd1 / d + λ′d1 / d) / (Cx + Cd), and the residual charge is detected as Q = (Cx + Cd) Vd = − (λd1 / d + λ′d1 / d). That is, if the reverse polarity voltage -Vo 'applied later has a sufficient time width for the disappearance of the previously formed space charge + λ and the formation of a new space charge -λ', these unipolar voltages are individually applied. The sum of the residual charges obtained when the voltage is applied is detected.
【００２６】[0026]
【発明の実施の形態】図３(ｂ)は本発明による残留電荷
の測定回路例である。図にて、１は試料絶縁体、２は単
極性の高電圧発生装置であり、この例ではインパルス電
圧Ｖｏを発生する。２ａはコンデンサであり、別の直流
高電圧発生装置から所定の電圧まで充電しておく。２ｄ
は放電ギャップであり、放電ギャップ２ｄの放電によっ
てコンデンサ２ａから試料１に単極性のインパルス電圧
を印加する。２ｂはインパルス電圧の充電時定数を決定
する抵抗、２ｃはインパルス電圧の放電時定数を決定す
る抵抗である。３は直流電荷検出用のコンデンサであ
り、その静電容量Ｃｄは試料１の静電容量Ｃｘに比べて
遥かに大きな値とする。４はコンデンサ３の電極間を短
絡するスイッチ、５はコンデンサの電極間電圧Vdを測定
する直流電圧計である。直流電圧計５の入力抵抗は、測
定期間中の電荷の漏洩を防ぐために、例えば１００ＭΩ
以上程度の高い値とする。なお、図３(ｂ)では印加電圧
としてインパルス波形を用いているが、単極性電圧であ
れば、方形波、三角波、sin半波形などのいずれでも良
い。また、図３(ｂ)では試料１の低圧電極と電荷検出用
コンデンサ３の接続点を接地に接続しているが、放電抵
抗２ｃと電荷検出用コンデンサ３の高圧側の接続点を接
地に接続する構成でも良い（接地点の変更によって電荷
検出用コンデンサ３の検出電圧Ｖｄの極性が反転す
る）。FIG. 3B is an example of a circuit for measuring residual charges according to the present invention. In the drawing, reference numeral 1 denotes a sample insulator, and 2 denotes a unipolar high voltage generator, which generates an impulse voltage Vo in this example. 2a is a capacitor which is charged to a predetermined voltage from another DC high voltage generator. 2d
Is a discharge gap, and a unipolar impulse voltage is applied to the sample 1 from the capacitor 2a by discharging in the discharge gap 2d. 2b is a resistor for determining a charging time constant of the impulse voltage, and 2c is a resistor for determining a discharging time constant of the impulse voltage. Reference numeral 3 denotes a DC charge detection capacitor whose capacitance Cd is set to a value much larger than the capacitance Cx of the sample 1. Reference numeral 4 denotes a switch for short-circuiting the electrodes of the capacitor 3, and reference numeral 5 denotes a DC voltmeter for measuring a voltage Vd between the electrodes of the capacitor. The input resistance of the DC voltmeter 5 is, for example, 100 MΩ in order to prevent leakage of electric charge during the measurement period.
It is a high value of about the above. In FIG. 3B, an impulse waveform is used as the applied voltage, but any unipolar voltage such as a square wave, a triangular wave, and a sin half waveform may be used. In FIG. 3B, the connection point between the low-voltage electrode of the sample 1 and the charge detection capacitor 3 is connected to ground, but the connection point between the discharge resistor 2c and the charge detection capacitor 3 on the high voltage side is connected to ground. (The polarity of the detection voltage Vd of the charge detection capacitor 3 is inverted by changing the ground point).
【００２７】いま、スイッチ４が開放された状態下で高
電圧発生装置のギャップ２ｄを放電すると、試料１と電
荷検出用コンデンサにはインパルス電圧Ｖｏが印加され
る。このとき、電荷検出用コンデンサ３の電極間電圧Ｖ
ｄを直流電圧計５で測定する。図４は、上記電極間電圧
Ｖｄの観測波形の模式図である。インパルス電圧−Ｖｏ
を印加した場合、−Ｖｏによって試料１の絶縁体中に空
間電荷が形成しないか、あるいは−Ｖｏによって空間電
荷が形成されても−Ｖｏの消滅と同時に空間電荷が消滅
する場合には、−Ｖｏの消滅とともに、Ｖｄは零に消滅
する。一方、−Ｖｏによって空間電荷が形成されて、−
Ｖｏ消滅後も絶縁体中に空間電荷が残存して静止してい
れば、Ｖｄは一定値＋△Ｖｄを保持して零にならない。
この＋△Ｖｄに試料と電荷検出用コンデンサの静電容量
の和（Ｃｘ+Ｃｄ）を掛け合わせた値がインパルス電圧
−Ｖｏ印加によって形成された残留電荷Ｑになる。When the gap 2d of the high voltage generator is discharged while the switch 4 is open, an impulse voltage Vo is applied to the sample 1 and the charge detection capacitor. At this time, the voltage V between the electrodes of the charge detection capacitor 3
d is measured by the DC voltmeter 5. FIG. 4 is a schematic diagram of an observed waveform of the inter-electrode voltage Vd. Impulse voltage-Vo
Is applied, no space charge is formed in the insulator of the sample 1 due to -Vo, or if space charge disappears at the same time as -Vo disappears even if space charge is formed due to -Vo, -Vo With the disappearance of Vd, Vd disappears to zero. On the other hand, a space charge is formed by -Vo, and-
If space charge remains in the insulator and remains stationary after Vo disappears, Vd maintains a constant value + ΔVd and does not become zero.
The value obtained by multiplying + △ Vd by the sum of the capacitance of the sample and the charge detection capacitor (Cx + Cd) is the residual charge Q formed by the application of the impulse voltage −Vo.
【００２８】次に、スイッチ４を短絡すると、電荷検出
用コンデンサ３の電極間電圧Ｖｄは零になる。また、こ
の時に、試料絶縁体中の空間電荷が消滅することなく静
止していれば、この空間電荷によって試料の両電極上に
は空間電荷と逆符号の電荷が誘導される。この状態でス
イッチ３の短絡を開放しても、試料絶縁体中の空間電荷
が静止していれば、コンデンサの電極間には電圧が現れ
ず零を保持している。このスイッチ３の短絡期間中にコ
ンデンサ２ａに最初の印加電圧とは逆極性の直流電圧を
印加しておき、最後に、一旦短絡したスイッチ３を再び
開放して、その後、逆極性のインパルス電圧＋Ｖｏを印
加する。この＋Ｖｏ印加時に、最初の−Ｖｏ印加時に形
成されていた空間電荷が消滅すると同時に、新たに逆極
性の空間電荷が形成され、かつ、＋Ｖｏが消滅後にも空
間電荷が絶縁体中に残留していると、電荷検出用コンデ
ンサの電極間には−２△Ｖｄなる電圧が検出される。こ
の電圧に試料と電荷検出用コンデンサの静電容量の和
（Ｃｘ+Ｃｄ）を掛け合わせた値がインパルス電圧−Ｖ
ｏ印加後逆極性の電圧＋Ｖｏを印加した場合の残留電荷
である。Next, when the switch 4 is short-circuited, the voltage Vd between the electrodes of the charge detection capacitor 3 becomes zero. At this time, if the space charge in the sample insulator is stationary without disappearing, a charge having a sign opposite to that of the space charge is induced on both electrodes of the sample by the space charge. Even if the short circuit of the switch 3 is opened in this state, if the space charge in the sample insulator is stationary, no voltage appears between the electrodes of the capacitor and the capacitor is kept at zero. During the short-circuit period of the switch 3, a DC voltage having a polarity opposite to the first applied voltage is applied to the capacitor 2a. Finally, the switch 3 which has been short-circuited is opened again, and thereafter, the impulse voltage + Vo having the opposite polarity is applied. Is applied. At the time of this + Vo application, the space charge formed at the time of the first -Vo application disappears, and at the same time, a space charge of the opposite polarity is newly formed, and after the + Vo disappears, the space charge remains in the insulator. Then, a voltage of -2 Vd is detected between the electrodes of the charge detection capacitor. The value obtained by multiplying this voltage by the sum of the capacitance of the sample and the charge detection capacitor (Cx + Cd) is the impulse voltage −V
This is the residual charge when a voltage + Vo of the opposite polarity is applied after o is applied.
【００２９】本発明にかかる残留電荷測定方法は、電力
ケーブルの絶縁劣化診断に好適に適用できる。この場
合、上述の絶縁体試料を診断すべき電力ケーブルの絶縁
層に置き換え、ケーブル導体を用いて単極性高電圧を印
加すれば良い。表１は、本発明の方法を用いて水トリー
劣化ＣＶケーブル試料の残留電荷を測定した結果を従来
法の結果に比較した例である。Ａは未劣化の２２ｋＶ・
ＣＶケーブルであり、Ｂは長大な内導水トリーが多発し
た１１ｋＶ・ＣＶケーブルである。インパルス電圧波形
としては波頭長が約５０μｓｅｃ、波尾長が約５０ｍｓ
とし、印加電圧の大きさを−１０ｋＶとした。従来法は
直流−３０ｋＶ印加後に交流１２．７ｋＶｒｍｓ印加し
た状態下で残留電荷を測定した。表から明らかなよう
に、本発明による残留電荷測定手法は、従来法に比較し
て全く遜色無くケーブルの劣化状況の差を検出してい
る。The method for measuring residual charge according to the present invention can be suitably applied to a diagnosis of insulation deterioration of a power cable. In this case, the above-mentioned insulator sample may be replaced with an insulating layer of a power cable to be diagnosed, and a unipolar high voltage may be applied using a cable conductor. Table 1 is an example in which the result of measuring the residual charge of a water tree deteriorated CV cable sample using the method of the present invention is compared with the result of the conventional method. A is undegraded 22kV
B is an 11 kV CV cable in which long and long internal water trees frequently occur. The impulse voltage waveform has a crest length of about 50 μsec and a crest length of about 50 ms
And the magnitude of the applied voltage was -10 kV. In the conventional method, the residual charge was measured in a state in which an alternating current of 12.7 kVrms was applied after applying a direct current of -30 kV. As is clear from the table, the residual charge measuring method according to the present invention detects the difference in the deterioration state of the cable with no difference as compared with the conventional method.
【００３０】[0030]
【表１】 [Table 1]
【００３１】[0031]
【発明の効果】以上説明した通りの本発明の絶縁体の残
留電荷測定方法によれば、印加した直流電圧を除去した
後においても消滅・移動しない空間電荷成分を残留電荷
として検出する方式を採用しているので、測定装置の大
型化を招来しがちな交流電圧印加設備が不要になると共
に、極めて信頼性の高い残留電荷測定を行うことができ
る。従って、本発明にかかる残留電荷測定方法を例えば
電力ケーブルの絶縁劣化診断に適用した場合、残留電荷
に基づく絶縁劣化診断を、高精度に且つ測定装置の大型
化を要すること無く実施することができるという優れた
効果を奏するものである。According to the method for measuring the residual charge of an insulator of the present invention as described above, a method is employed in which a space charge component which does not disappear or move even after the applied DC voltage is removed is detected as a residual charge. This eliminates the need for an AC voltage application facility that tends to increase the size of the measuring device, and enables highly reliable measurement of the residual charge. Therefore, when the residual charge measurement method according to the present invention is applied to, for example, insulation deterioration diagnosis of a power cable, insulation deterioration diagnosis based on the residual charge can be performed with high accuracy and without requiring an increase in the size of the measurement device. This is an excellent effect.
【図１】従来の残留電荷測定方法を示す回路図であっ
て、(ａ)は電流測定法、(ｂ)は電圧測定法、(ｃ)交流電
圧印加法をそれぞれ示す。FIG. 1 is a circuit diagram showing a conventional method for measuring residual charges, wherein (a) shows a current measuring method, (b) shows a voltage measuring method, and (c) shows an AC voltage applying method.
【図２】従来の残留電荷測定方法により検出される残留
電荷の時間特性を示すグラフ図である。FIG. 2 is a graph showing a time characteristic of a residual charge detected by a conventional residual charge measuring method.
【図３】本発明の残留電荷測定方法を示す回路図であっ
て、(ａ)はその原理を示す回路図、(ｂ)は実施態様の一
例を示す回路図である。3A and 3B are circuit diagrams showing a method for measuring residual charges according to the present invention, wherein FIG. 3A is a circuit diagram showing the principle thereof, and FIG. 3B is a circuit diagram showing an example of the embodiment.
【図４】本発明の測定を行うための模式図である。FIG. 4 is a schematic diagram for performing the measurement of the present invention.
１ 試料絶縁体 ２ 単極性の高電圧発生装置 ３ 電荷測定用コンデンサ ４ 開閉スイッチ DESCRIPTION OF SYMBOLS 1 Sample insulator 2 Unipolar high voltage generator 3 Capacitor for charge measurement 4 On / off switch
─────────────────────────────────────────────────────
────────────────────────────────────────────────── ───
【手続補正書】[Procedure amendment]
【提出日】平成１１年１２月２１日（１９９９．１２．
２１）[Submission date] December 21, 1999 (1999.12.
21)
【手続補正１】[Procedure amendment 1]
【補正対象書類名】明細書[Document name to be amended] Statement
【補正対象項目名】特許請求の範囲[Correction target item name] Claims
【補正方法】変更[Correction method] Change
【補正内容】[Correction contents]
【特許請求の範囲】[Claims]
【手続補正２】[Procedure amendment 2]
【補正対象書類名】明細書[Document name to be amended] Statement
【補正対象項目名】００１４[Correction target item name] 0014
【補正方法】変更[Correction method] Change
【補正内容】[Correction contents]
【００１４】[0014]
【課題を解決するための手段】本発明の絶縁体の残留電
荷測定方法は、試料絶縁体とコンデンサの直列接続体に
正又は負の単極性高電圧Ｖｏを印加し、このときのコン
デンサ分担電圧を直流電圧計で観測し、単極性電圧印加
後に残留するコンデンサ分担電圧に基づいて試料絶縁体
中に蓄積した電荷を検出することを特徴とするものであ
る。According to the present invention, there is provided a method for measuring the residual electric charge of an insulator, comprising applying a positive or negative unipolar high voltage Vo to a series connection of a sample insulator and a capacitor, Is observed with a DC voltmeter, and the electric charge accumulated in the sample insulator is detected based on the capacitor shared voltage remaining after the application of the unipolar voltage.
【手続補正３】[Procedure amendment 3]
【補正対象書類名】明細書[Document name to be amended] Statement
【補正対象項目名】００１５[Correction target item name] 0015
【補正方法】変更[Correction method] Change
【補正内容】[Correction contents]
【００１５】また本発明の他の測定方法は、上記した測
定をなした後に、一旦コンデンサの電極間を短絡し、そ
の後短絡を開放した状態で、最初に印加した上記単極性
高電圧Vｏと逆極性の電圧−Vｏをさらに印加し、次いで
このときのコンデンサ分担電圧を直流電圧計で観測し、
単極性電圧印加後に残留するコンデンサ分担電圧に基づ
いて試料絶縁体中に蓄積した電荷を検出することを特徴
とするものである。In another measurement method of the present invention, after performing the above-described measurement, the electrodes of the capacitor are short-circuited once, and then the short-circuit is opened, and the reverse is applied to the unipolar high voltage Vo applied first. Polarity voltage -Vo is further applied, and then the capacitor sharing voltage at this time is observed with a DC voltmeter,
The electric charge accumulated in the sample insulator is detected on the basis of the capacitor shared voltage remaining after the application of the unipolar voltage.
Claims (3)
正又は負の単極性高電圧Ｖｏを印加し、このときのコン
デンサ分担電圧を直流電圧計で観測し、パルス電圧印加
後に残留するコンデンサ分担電圧に基づいて試料絶縁体
中に蓄積した電荷を検出することを特徴とする絶縁体の
残留電荷測定方法。1. A positive or negative unipolar high voltage Vo is applied to a series connection of a sample insulator and a capacitor, the capacitor sharing voltage at this time is observed with a DC voltmeter, and the capacitor sharing voltage remaining after the pulse voltage is applied. A method for measuring the residual charge of an insulator, comprising detecting a charge accumulated in a sample insulator based on the method.
デンサの電極間を短絡し、その後短絡を開放した状態
で、最初に印加した上記単極性高電圧Vｏと逆極性の電
圧−Vｏをさらに印加し、次いでこのときのコンデンサ
分担電圧を直流電圧計で観測し、パルス電圧印加後に残
留するコンデンサ分担電圧に基づいて試料絶縁体中に蓄
積した電荷を検出することを特徴とする絶縁体の残留電
荷測定方法。2. After the measurement of claim 1, the capacitor is short-circuited once and the short-circuit is released, and then the voltage -Vo of the opposite polarity to the unipolar high voltage Vo applied first is applied. Further applying the voltage, then observing the capacitor sharing voltage at this time with a DC voltmeter, and detecting the charge accumulated in the sample insulator based on the capacitor sharing voltage remaining after the pulse voltage is applied. Charge measurement method.
において、試料絶縁体を電力ケーブルの絶縁層とし、当
該測定により得られた残留電荷に基づいて前記絶縁層の
絶縁劣化度合いを診断することを特徴とする電力ケーブ
ルの絶縁劣化診断方法。3. The residual charge measuring method according to claim 1, wherein the sample insulator is used as an insulating layer of a power cable, and a degree of insulation deterioration of the insulating layer is diagnosed based on the residual charge obtained by the measurement. A method for diagnosing power cable insulation deterioration.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP29906199A JP2001116789A (en) | 1999-10-21 | 1999-10-21 | Method for measuring residual charge of insulator and method for diagnosing insulation deterioration of power cable using it |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP29906199A JP2001116789A (en) | 1999-10-21 | 1999-10-21 | Method for measuring residual charge of insulator and method for diagnosing insulation deterioration of power cable using it |
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| Publication Number | Publication Date |
|---|---|
| JP2001116789A true JP2001116789A (en) | 2001-04-27 |
Family
ID=17867707
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP29906199A Ceased JP2001116789A (en) | 1999-10-21 | 1999-10-21 | Method for measuring residual charge of insulator and method for diagnosing insulation deterioration of power cable using it |
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| Country | Link |
|---|---|
| JP (1) | JP2001116789A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007271542A (en) * | 2006-03-31 | 2007-10-18 | Exsym Corp | Insulation deterioration diagnosis method and insulation deterioration diagnosis device of power cable |
| JP2009186334A (en) * | 2008-02-06 | 2009-08-20 | Chubu Electric Power Co Inc | Power cable deterioration position locating method and its device |
| CN106093611A (en) * | 2016-06-20 | 2016-11-09 | 南方电网科学研究院有限责任公司 | converter transformer paper oil insulation surface charge measuring device |
| CN106154063A (en) * | 2016-06-20 | 2016-11-23 | 南方电网科学研究院有限责任公司 | converter transformer paper oil insulation surface charge measuring device and measuring method thereof |
-
1999
- 1999-10-21 JP JP29906199A patent/JP2001116789A/en not_active Ceased
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007271542A (en) * | 2006-03-31 | 2007-10-18 | Exsym Corp | Insulation deterioration diagnosis method and insulation deterioration diagnosis device of power cable |
| JP2009186334A (en) * | 2008-02-06 | 2009-08-20 | Chubu Electric Power Co Inc | Power cable deterioration position locating method and its device |
| CN106093611A (en) * | 2016-06-20 | 2016-11-09 | 南方电网科学研究院有限责任公司 | converter transformer paper oil insulation surface charge measuring device |
| CN106154063A (en) * | 2016-06-20 | 2016-11-23 | 南方电网科学研究院有限责任公司 | converter transformer paper oil insulation surface charge measuring device and measuring method thereof |
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