JP2985154B2 - Power cable conductor current measurement method - Google Patents
Power cable conductor current measurement methodInfo
- Publication number
- JP2985154B2 JP2985154B2 JP2048826A JP4882690A JP2985154B2 JP 2985154 B2 JP2985154 B2 JP 2985154B2 JP 2048826 A JP2048826 A JP 2048826A JP 4882690 A JP4882690 A JP 4882690A JP 2985154 B2 JP2985154 B2 JP 2985154B2
- Authority
- JP
- Japan
- Prior art keywords
- signal
- magnetic field
- field sensor
- power cable
- cable
- 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
Landscapes
- Measuring Instrument Details And Bridges, And Automatic Balancing Devices (AREA)
- Measurement Of Current Or Voltage (AREA)
Description
【発明の詳細な説明】 ［産業上の利用分野］ 本発明は、洞道内布設電力ケーブルの胴体に流れる導
体電流を遠隔測定するための電力ケーブルの導体電流測
定方法に関するものである。Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for measuring a conductor current of a power cable for remotely measuring a conductor current flowing through a body of a power cable laid in a sinus.
［従来の技術］ 高圧の電力ケーブルを保守監視する上で、ケーブル導
体を流れる導体電流を正確に測定することが重要であ
る。このため、従来から電力ケーブルに流れる交流電流
によってケーブル周囲に発生する交流磁界を二次コイル
で検出し、電流測定を行う所謂CT（Current Transforme
r）と称する磁界センサが用いられることが多い。2. Description of the Related Art It is important to accurately measure a conductor current flowing through a cable conductor in maintaining and monitoring a high-voltage power cable. For this reason, a so-called CT (Current Transforme) that conventionally measures an AC magnetic field generated around a cable by an AC current flowing through a power cable with a secondary coil and measures the current.
Magnetic field sensors referred to as r) are often used.
［発明が解決しようとする課題］ しかしながら、従来用いられている磁界センサでは、
検出コイルを電力ケーブルの最外周に配置しているの
で、測定すべき導体電流だけでなく、例えばケーブルシ
ースを流れるシース電流の影響をも受けて正確な導体電
流測定ができないという問題がある。[Problems to be Solved by the Invention] However, in the magnetic field sensor conventionally used,
Since the detection coil is arranged at the outermost periphery of the power cable, there is a problem that accurate conductor current measurement cannot be performed due to the influence of not only the conductor current to be measured but also, for example, the sheath current flowing through the cable sheath.
本発明の目的は、シース電流等の影響を除去して、導
体電流のみを正確に測定できる電力ケーブルの導体電流
測定方法を提供することにある。An object of the present invention is to provide a method for measuring a conductor current of a power cable, which can accurately measure only a conductor current by removing the influence of a sheath current or the like.
［課題を解決するための手段］ 上述の目的を達成するために、本発明に係る電力ケー
ブルの導体電流測定方法においては、電力ケーブルの周
囲に発生する磁界を検出して前記電力ケーブルの導体を
流れる電流を測定する電流測定方法において、絶縁接続
部を介して接続される洞道内布設電力ケーブルの周囲に
ケーブル用磁界センサと電源用磁界センサを周設すると
共に、前記電力ケーブルのシース線に接続される接地線
の周囲に接地線用磁界センサを周設し、前記ケーブル用
磁界センサから得られる出力信号と前記接地線用磁界セ
ンサから得られる出力信号との差動信号を、前記電源用
磁界センサから得られる電流を電源とした測定回路に入
力し、ここで半波整流器で半波整流すると共に基準信号
生成回路からの所定の基準信号を重畳して送出信号を生
成しさらにこの送出信号を電圧一光変換器により光信号
に変換し、この変換された光信号を光ファイバを介して
光受信器に送出し、光一電圧変換器により電気信号に変
換すると共にA/D変換器によりデジタル信号に変換し、
このデジタル信号をインターフェイスを介してコンピュ
ータに接続することにより、前記電力ケーブルの導体電
流を遠隔的に自動測定できるように構成したことを特徴
とする。Means for Solving the Problems In order to achieve the above-mentioned object, in the conductor current measuring method for a power cable according to the present invention, a conductor of the power cable is detected by detecting a magnetic field generated around the power cable. In a current measuring method for measuring a flowing current, a magnetic field sensor for a cable and a magnetic field sensor for a power supply are provided around a power cable laid in a sinus which is connected through an insulated connecting portion, and connected to a sheath wire of the power cable. A magnetic field sensor for the ground line is provided around the ground line to be connected, and a differential signal between an output signal obtained from the magnetic field sensor for the cable and an output signal obtained from the magnetic field sensor for the ground line is supplied to the magnetic field for the power supply. The current obtained from the sensor is input to a measurement circuit using the power as a power source. An outgoing signal is generated, and this outgoing signal is converted into an optical signal by a voltage-to-optical converter. The converted optical signal is transmitted to an optical receiver via an optical fiber, and is converted into an electric signal by the optical-to-voltage converter And at the same time convert to digital signal by A / D converter,
The digital signal is connected to a computer via an interface so that the conductor current of the power cable can be remotely and automatically measured.
［作用］ 上述の構成を有する電力ケーブルの導体電流測定方法
によれば、絶縁接続部を介して接続される洞道内布設電
力ケーブルの周囲で導体電流とシース電流の和の値を、
電源用磁界センサを介して電力ケーブルから得られた電
源により作動する測定回路により測定すると共に、接地
線の周囲でシース電流を測定し、これらの差動出力を光
信号により遠隔送信して導体電流を求める。[Operation] According to the method for measuring the conductor current of the power cable having the above-described configuration, the value of the sum of the conductor current and the sheath current around the power cable laid in the sinus which is connected via the insulated connection portion is calculated by:
The measurement is performed by a measurement circuit operated by the power supply obtained from the power cable via the power supply magnetic field sensor, and the sheath current is measured around the ground wire. Ask for.
［実施例］ 本発明に係る方法を図示の実施例に基づいて詳細に説
明する。[Example] The method according to the present invention will be described in detail based on the illustrated example.
第１図は本発明の方法を実施するための結線図であ
る。絶縁接続部Ｊで電力ケーブルの導体Ｃ同志が接続さ
れ、ケーブルシースＳ同志は絶縁されており、右側のケ
ーブルシースＳは接地線Ｇを介して地緒されている。こ
のような絶縁接続部Ｊにおいて、右側の電力ケーブルに
はケーブル用磁界センサ１、接地線Ｇには接地線用磁界
センサ２を取り付け、ケーブル用磁界センサ１の出力と
接地線用磁界センサ２の出力とを測定回路３に差動的に
接続する。また、測定回路３の電源はケーブル用磁界セ
ンサと共に電力ケーブルに取り付けた電源用磁界センサ
５を介して、測定すべき電力ケーブルから供給されてい
る。測定回路３の出力は光ファイバ４を介して光受信機
６に接続され、光受信機６の出力はコンピュータ７、オ
シロスコープ等の出力装置８に接続されている。なお、
磁界センサ１、２、５は装着前は分割型となっていて、
装着後に円環状としてケーブルＣ、接地線Ｇをそれぞれ
周回する。FIG. 1 is a connection diagram for carrying out the method of the present invention. The conductors C of the power cable are connected at the insulated connection portion J, the cable sheaths S are insulated, and the right cable sheath S is grounded via the ground wire G. In such an insulated connection portion J, a cable magnetic field sensor 1 is attached to the right power cable, a ground wire magnetic field sensor 2 is attached to the ground wire G, and the output of the cable magnetic field sensor 1 and the ground wire magnetic sensor 2 are connected. The output is differentially connected to the measurement circuit 3. The power of the measuring circuit 3 is supplied from the power cable to be measured via the power magnetic field sensor 5 attached to the power cable together with the cable magnetic field sensor. The output of the measuring circuit 3 is connected to an optical receiver 6 via an optical fiber 4, and the output of the optical receiver 6 is connected to an output device 8 such as a computer 7 or an oscilloscope. In addition,
The magnetic field sensors 1, 2, and 5 are divided before mounting,
After the attachment, the cable C and the ground wire G are respectively circulated in an annular shape.
ケーブル用磁界センサ１によって得られる導体電流Ic
と接地線用磁界センサ２によって得られるシース電流Is
の和を与える測定値を、シース電流Isのみの測定値との
差動信号をとることによって、正確な導体電流Icを求め
ることができる。即ち、電源用磁界センサ５からの電流
の供与により作動する第２図に示す測定回路３では、ケ
ーブル用磁界センサ１と接地線用磁界センサ２との差動
信号を半波整流器31で半波整流すると共に、基準信号生
成回路32ではこの差動信号が負相に転じた時点の例えば
2ms後から、2ms間の基準値が連続する基準信号を重畳し
て、第３図に示すような送出信号を生成する。Conductor current Ic obtained by cable magnetic field sensor 1
And the sheath current Is obtained by the ground wire magnetic field sensor 2
By taking a differential signal from a measured value that gives the sum of the measured values of the sheath current Is alone, an accurate conductor current Ic can be obtained. That is, in the measuring circuit 3 shown in FIG. 2 which operates by supplying a current from the power supply magnetic field sensor 5, the differential signal between the cable magnetic field sensor 1 and the ground wire magnetic field sensor 2 is converted into a half-wave Along with the rectification, the reference signal generating circuit 32, for example, at the time when the differential signal turns
After 2 ms, a reference signal having a continuous reference value for 2 ms is superimposed to generate a transmission signal as shown in FIG.
次いで、この送出信号をバッファ33を介してパルス幅
変調回路34に入力し、このパルス幅変調回路34では三角
波発振器35で発振する基準三角波との比較により、ゲー
トを開閉する等の方法によって送出信号のパルス幅変調
を行う。更に、この変調信号を発光素子等の電圧一光変
換器36により光変換して、光ファイバ４に送信する。Next, the transmission signal is input to a pulse width modulation circuit 34 via a buffer 33, and the pulse width modulation circuit 34 compares the transmission signal with a reference triangular wave oscillated by a triangular wave oscillator 35 to open and close the gate, for example. Is performed. Further, the modulated signal is optically converted by a voltage-to-optical converter 36 such as a light emitting element and transmitted to the optical fiber 4.
このようにして、光ファイバ４に送出された光信号
を、第４図のブロック回路図に示す構成の光受信機６で
受信し、コンピュータ７や出力装置８で測定する。即
ち、光受信機６では光ファイバ４からの光信号を受光素
子等の光電圧変換器61で電気信号に変換する。このパル
ス幅変調波形はA/D変換器62で適当なデジタル信号に変
換してCPU63で処理し、例えばRS232C規格等のインタフ
ェース64を介してコンピュータ７と接続することによ
り、自動測定、自動制御等を行うことも可能である。こ
の際に、測定装置３で半波整流波形に重畳した基準信号
は、波高値や時間の基準として用いることができる．ま
た、パルス幅復調回路65で変調波形を復調し、適当なバ
ッファ66を介して出力し、出力装置８等に接続して波形
の観察、監視を行ってもよい。Thus, the optical signal transmitted to the optical fiber 4 is received by the optical receiver 6 having the configuration shown in the block circuit diagram of FIG. 4, and measured by the computer 7 and the output device 8. That is, in the optical receiver 6, an optical signal from the optical fiber 4 is converted into an electric signal by an optical voltage converter 61 such as a light receiving element. This pulse width modulated waveform is converted into an appropriate digital signal by the A / D converter 62, processed by the CPU 63, and connected to the computer 7 via an interface 64 such as the RS232C standard, for example, for automatic measurement and automatic control. It is also possible to do. At this time, the reference signal superimposed on the half-wave rectified waveform by the measuring device 3 can be used as a reference for the peak value or time. Alternatively, the modulated waveform may be demodulated by the pulse width demodulation circuit 65, output via an appropriate buffer 66, and connected to the output device 8 or the like to observe and monitor the waveform.
［発明の効果］ 以上説明したように本発明に係る電力ケーブルの導体
電流測定方法は、接地線の周囲でシース電流を測定し、
この値を電力ケーブルから得られた電流から差動的に除
去しているので正確な導体電流が測定でき、しかも光フ
アイバを用いて光信号で測定波形を送受しているので高
電圧ケーブルの測定でも不要な誘導が防止でき、洞道内
布設された高電圧の電力ケーブルの遠隔的保守監視が正
しく実施できる。[Effect of the Invention] As described above, the conductor current measuring method for a power cable according to the present invention measures a sheath current around a ground wire,
Since this value is differentially removed from the current obtained from the power cable, accurate conductor current can be measured.Moreover, since the measurement waveform is transmitted and received using an optical signal using an optical fiber, measurement of a high voltage cable is performed. However, unnecessary guidance can be prevented, and remote maintenance and monitoring of the high-voltage power cable laid in the tunnel can be performed correctly.
また、測定回路における半波整流器で半波整流すると
共に基準信号生成回路からの所定の基準信号を重畳して
送出信号を生成しているため、この信号から波高値や時
間の基準として用いることができ、より高精度なケーブ
ル導体電流測定が可能となる。In addition, since the transmission signal is generated by half-wave rectification by the half-wave rectifier in the measurement circuit and by superimposing a predetermined reference signal from the reference signal generation circuit, the signal can be used as a reference for the peak value or time. This makes it possible to measure the cable conductor current with higher accuracy.
さらには、測定回路の電源を電源用磁界センサにより
供給するので、別途に電源線等を布設する必要もなく、
測定用電源が入手困難な洞道内布設の電力ケーブルに対
して本測定方法は特に好適である。Furthermore, since the power of the measurement circuit is supplied by the power supply magnetic field sensor, there is no need to separately lay a power supply line or the like,
This measurement method is particularly suitable for a power cable laid in a sinus where it is difficult to obtain a measurement power source.
図面は本発明に係る電力ケーブルの導体電流測定方法の
実施例を示し、第１図は本発明の方法を実施するための
結線図、第２図は測定回路のブロック回路図、第３図は
送出波形の説明図、第４図は光受信機のブロック回縮図
である。 符号Ｊは絶縁接続部、Ｃはケーブル導体、Ｓはケーブル
シース、Ｇは接地線、１はケーブル円磁界センサ、２は
接地線用磁界センサ、３は測定回路、４は光ファイバ、
５は電源用磁界センサ、６は光受信機、７はコンピュー
タ、８は出力装置である。The drawings show an embodiment of the method for measuring the conductor current of a power cable according to the present invention, FIG. 1 is a connection diagram for implementing the method of the present invention, FIG. 2 is a block circuit diagram of a measuring circuit, and FIG. FIG. 4 is an explanatory diagram of a transmission waveform, and FIG. 4 is a block diagram of the optical receiver. Symbol J is an insulated connecting portion, C is a cable conductor, S is a cable sheath, G is a ground wire, 1 is a cable circular magnetic field sensor, 2 is a ground wire magnetic field sensor, 3 is a measurement circuit, 4 is an optical fiber,
5 is a magnetic field sensor for power supply, 6 is an optical receiver, 7 is a computer, and 8 is an output device.
───────────────────────────────────────────────────── フロントページの続き (58)調査した分野(Int.Cl.6，ＤＢ名) G01R 15/18 G01R 19/00 G01R 31/02 ──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. 6 , DB name) G01R 15/18 G01R 19/00 G01R 31/02
Claims (1)
して前記電力ケーブルの導体を流れる電流を測定する電
流測定方法において、絶縁接続部を介して接続される洞
道内布設電力ケーブルの周囲にケーブル用磁界センサと
電源用磁界センサを周設すると共に、前記電力ケーブル
のシース線に接続される接地線の周囲に接地線用磁界セ
ンサを周設し、前記ケーブル用磁界センサから得られる
出力信号と前記接地線用磁界センサから得られる出力信
号との差動信号を、前記電源用磁界センサから得られる
電流を電源とした測定回路に入力し、ここで半波整流器
で半波整流すると共に基準信号生成回路からの所定の基
準信号を重畳して送出信号を生成しさらにこの送出信号
を電圧一光変換器により光信号に変換し、この変換され
た光信号を光ファイバを介して光受信機に送出し、光一
電圧変換器により電気信号に変換すると共にA/D変換器
によりデジタル信号に変換し、このデジタル信号をイン
ターフェイスを介してコンピュータに接続することによ
り、前記電力ケーブルの導体電流を遠隔的に自動測定で
きるように構成したことを特徴とする電力ケーブルの導
体電流測定方法。In a current measuring method for detecting a magnetic field generated around a power cable and measuring a current flowing through a conductor of the power cable, the current measuring method includes the steps of: A magnetic field sensor for a cable and a magnetic field sensor for a power supply are provided around the magnetic field sensor for a ground wire around a ground wire connected to a sheath wire of the power cable, and an output signal obtained from the magnetic field sensor for the cable is provided. And a differential signal between the output signal obtained from the ground line magnetic field sensor and a measurement circuit using a current obtained from the power supply magnetic field sensor as a power supply. A transmission signal is generated by superimposing a predetermined reference signal from the signal generation circuit, the transmission signal is converted into an optical signal by a voltage-to-optical converter, and the converted optical signal is converted into an optical signal. By sending the signal to an optical receiver via an optical-to-voltage converter, converting the signal into a digital signal with an A / D converter, and connecting the digital signal to a computer via an interface, A method for measuring the conductor current of a power cable, characterized in that the conductor current of the power cable can be automatically measured remotely.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2048826A JP2985154B2 (en) | 1990-02-28 | 1990-02-28 | Power cable conductor current measurement method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2048826A JP2985154B2 (en) | 1990-02-28 | 1990-02-28 | Power cable conductor current measurement method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH03251771A JPH03251771A (en) | 1991-11-11 |
| JP2985154B2 true JP2985154B2 (en) | 1999-11-29 |
Family
ID=12814035
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2048826A Expired - Lifetime JP2985154B2 (en) | 1990-02-28 | 1990-02-28 | Power cable conductor current measurement method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2985154B2 (en) |
-
1990
- 1990-02-28 JP JP2048826A patent/JP2985154B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH03251771A (en) | 1991-11-11 |
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