JPH04131768A - Output circuit of current transformer - Google Patents

Output circuit of current transformer

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Publication number
JPH04131768A
JPH04131768A JP2251963A JP25196390A JPH04131768A JP H04131768 A JPH04131768 A JP H04131768A JP 2251963 A JP2251963 A JP 2251963A JP 25196390 A JP25196390 A JP 25196390A JP H04131768 A JPH04131768 A JP H04131768A
Authority
JP
Japan
Prior art keywords
current transformer
resistor
detector
resistance value
current
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
Application number
JP2251963A
Other languages
Japanese (ja)
Other versions
JP2701524B2 (en
Inventor
Matsukichi Kato
松吉 加藤
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Takaoka Toko Co Ltd
Original Assignee
Takaoka Electric Mfg Co Ltd
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Filing date
Publication date
Application filed by Takaoka Electric Mfg Co Ltd filed Critical Takaoka Electric Mfg Co Ltd
Priority to JP2251963A priority Critical patent/JP2701524B2/en
Publication of JPH04131768A publication Critical patent/JPH04131768A/en
Application granted granted Critical
Publication of JP2701524B2 publication Critical patent/JP2701524B2/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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  • Measurement Of Current Or Voltage (AREA)
  • Transformers For Measuring Instruments (AREA)
  • Measuring Instrument Details And Bridges, And Automatic Balancing Devices (AREA)

Abstract

PURPOSE:To provide precise measurability for the secondary current of a current transformer by connecting a bunch of serially connected resistors to the output side of the current transformer, and equipping each resistor with a sensor to sense the output from the ends of the resistor. CONSTITUTION:Each voltage Vi generated at the ends of each resistor 21, 22, 23..., 2n in series connection is expressed as Vi=I2XR2iXR3i/(R2i+R3i), where I2 is secondary current of a current transformer 1, R2I is each resistance value of resistor 21, 22, 23..., 2n, and R3i is input resistance value of each sensor 31, 32, 33..., 3n, wherein (i) takes 1 thru n. Accordingly the sensors 31, 32, 33..., 3n will measure the secondary current of the current transformer 1 through sensing of the voltages Vi, and eventually removed sensor does not affect the other sensors, which permits precise measurement of the transformer secondary current.

Description

【発明の詳細な説明】 「産業上の利用分野」 本発明は１台の変流器から複数の出力を得る変流器出力
回路に関する。DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a current transformer output circuit that obtains a plurality of outputs from one current transformer.

「従来の技術」 変流器の出力は保護リレーや計測などの用途に使用され
る。また、保護リレー装置や計測を行う装置は、それぞ
れ独立した装置で構成し、さらに保護リレー装置などに
おいては、信頼性の向上の観点から二系列化、二重化な
どを行い、複数の装置で構成される。これらの装置では
１台の変流器から出力を受取り、それぞれの機能を果た
している。このため、１台の変流器から複数の出力を得
る変流器出力回路が必要であった。``Conventional technology'' The output of current transformers is used for purposes such as protection relays and measurements. In addition, protective relay devices and measurement devices are each made up of independent devices, and in order to improve reliability, protection relay devices are configured with multiple devices, such as dual series or duplication. Ru. These devices receive output from a single current transformer and perform their respective functions. Therefore, a current transformer output circuit that obtains multiple outputs from one current transformer is required.

第２図に１台の変流器から複数の出力を得る場合の従来
の変流器出力回路を示す。この回路は変流器（１）の出
力に１つの抵抗器（４１）を接続し、その抵抗器（４１
）に複数の検出器（５１，５２，５３、・・・　５ｎ）
を並列接続した出力回路としている。FIG. 2 shows a conventional current transformer output circuit for obtaining a plurality of outputs from one current transformer. This circuit connects one resistor (41) to the output of the current transformer (1), and the resistor (41)
) with multiple detectors (51, 52, 53,... 5n)
The output circuit is connected in parallel.

この回路の検出原理は次の通りである。The detection principle of this circuit is as follows.

各検出器（５１，５２，５３、・・・、５ｎ）の入力抵
抗の抵抗値をＲ５１、Ｒ５２、Ｒ５３、・・Ｒ５ｎ、抵
抗器（４１）の抵抗値をＲ４１とすると、変流器（１）
の出力側に接続される負荷抵抗の抵抗値Ｒｏは、抵抗器
（４１）に各検出器（５１，５２，５３、・・・、５ｎ
）の入力抵抗がそれぞれ並列接続されるため、１　／　
Ｒｏ　−１／　Ｒ４１＋１／Ｒ５１＋１／Ｒ５２＋１／
Ｒ５３＋・・・＋　１　／　Ｒ５ｎとなる。したかって
、抵抗器（４１）の両端に生しる電圧Ｖｏは、変流器（
１）の二次電流を■２とすると、Ｖｏ＝　Ｉ　２ＸＲｏ
となり、各検出器（５１，５２，５３、・・・　５ｎ）
はこの抵抗器（４１）の両端に生じる電圧ＶＯを検出し
、変流器（１）の二次電流を測定することになる。If the resistance value of the input resistance of each detector (51, 52, 53, ..., 5n) is R51, R52, R53, ... R5n, and the resistance value of the resistor (41) is R41, then the current transformer ( 1)
The resistance value Ro of the load resistor connected to the output side of the resistor (41) and each detector (51, 52, 53, ..., 5n
) are connected in parallel, so 1/
Ro -1/ R41+1/R51+1/R52+1/
R53+...+1/R5n. Therefore, the voltage Vo generated across the resistor (41) is equal to the current transformer (
If the secondary current of 1) is 2, then Vo= I 2XRo
and each detector (51, 52, 53,... 5n)
detects the voltage VO generated across this resistor (41) and measures the secondary current of the current transformer (1).

「発明か解決しようとする問題点」 上記従来技術においては、各検出器（５１，５２，５３
、・・・　５ｎ）が抵抗器（４１）にそれぞれ並列接続
されるため、各検出器（５１，５２，５３、・・・、５
ｎ）の入力抵抗の並列合成抵抗値が抵抗器（４１）の抵
抗値Ｒ４１に比べ十分に高い必要があり、このため、各
検出器（５１，５２，５３、・・・、５ｎ）の入力抵抗
の抵抗値Ｒ５１、Ｒ５２、Ｒ５３、・・・、Ｒ５ｎをさ
らに高くする必要があった。"Problem to be solved by invention" In the above conventional technology, each detector (51, 52, 53
,...5n) are connected in parallel to the resistor (41), so each detector (51, 52, 53,..., 5n) is connected in parallel to the resistor (41).
It is necessary that the parallel combined resistance value of the input resistances (n) is sufficiently higher than the resistance value R41 of the resistor (41). It was necessary to further increase the resistance values R51, R52, R53, . . . , R5n of the resistors.

しかし、耐ノイズ性能の向上のため、各検出器（５１，
５２，５３、・・・、５ｎ）の入力抵抗の抵抗値Ｒ５１
、Ｒ５２、Ｒ５３、・・・、Ｒ５ｎを高くできない場合
がある。この場合には、保守などの理由から、例えば検
出器（５１）を取外した状態で、他の検出器（５２，５
３、・・・　５ｎ）て変流器（１）の二次電流の計測を
継続する場合、検出器（５１）を取外す前と後では変流
器（１）の出力側に接続される負荷抵抗の抵抗値Ｒｏの
値か変化し、抵抗器（４１）の両端に生じる電圧■０か
変化する。このため、測定を継続している検出器（５２
，５３、・・・、５ｎ）は誤った変流器（１）の二次電
流を測定する問題があった。However, in order to improve noise resistance performance, each detector (51,
52, 53, ..., 5n) resistance value R51 of the input resistance
, R52, R53, . . . , R5n may not be made high. In this case, for reasons such as maintenance, for example, with the detector (51) removed, other detectors (52, 5
3,...5n) to continue measuring the secondary current of the current transformer (1), the load connected to the output side of the current transformer (1) before and after removing the detector (51). The resistance value Ro of the resistor changes, and the voltage generated across the resistor (41) changes to zero. For this reason, the detector (52
, 53, . . . , 5n) had the problem of incorrectly measuring the secondary current of the current transformer (1).

また、検出器の入力抵抗の抵抗値が高い場合であっても
、どれかの検出器の故障などにより検出器の入力抵抗が
変化する場合があり、この場合にも変流器（１）の出力
側に接続される負荷抵抗の抵抗値Ｒｏの値が変化し、抵
抗器（４１）の両端に生じる電圧Ｖｏが変化し、正常な
検出器において誤った変流器（１）の二次電流を測定す
る問題があった。例えば、検出器（５１）が故障し、入
力抵抗の抵抗値が零となった場合、抵抗器（４１）の両
端に生じる電圧Ｖｏは■０＝０となり、他の正常な検出
器（５２，５３、・・、５ｎ）においても雰を検出し、
誤った変流器（１）の二次電流を測定する問題かあった
。In addition, even if the resistance value of the input resistance of the detector is high, the input resistance of the detector may change due to a failure of one of the detectors, and in this case, the current transformer (1) The resistance value Ro of the load resistor connected to the output side changes, and the voltage Vo generated across the resistor (41) changes, causing an incorrect secondary current of the current transformer (1) in a normal detector. There was a problem in measuring. For example, if the detector (51) fails and the resistance value of the input resistor becomes zero, the voltage Vo generated across the resistor (41) becomes 0=0, and the other normal detectors (52, 53,..., 5n) also detect atmosphere,
There was a problem of measuring the secondary current of the wrong current transformer (1).

「問題点を解決するための手段」 上記問題点を解決するため、本発明では、変流器（１）
の出力側に複数の抵抗器（２１，２２，２３、・・・、
２ｎ）を直列接続した抵抗器群を接続し、その各抵抗器
（２１，２２，２３、・・・、２ｎ）の両端の出力を検
出する検出器（３１，３２，３３、・・、３ｎ）を各抵
抗器（２１，２２，２３、・・・、２ｎ）に対してそれ
ぞれ設ける。"Means for Solving the Problems" In order to solve the above problems, the present invention provides a current transformer (1).
Multiple resistors (21, 22, 23, ...,
A detector (31, 32, 33,..., 3n) connects a group of resistors (2n) connected in series and detects the output from both ends of each resistor (21, 22, 23,..., 2n). ) are provided for each resistor (21, 22, 23, . . . , 2n).

「作用」 本発明は上記の如く構成することにより、検出器の入力
抵抗の抵抗値が抵抗器の抵抗値に対して十分に高くでき
ない場合においである検出器を取外しても、また、故障
などによりある検出器の入力抵抗の抵抗値が変化した場
合であっても、それ以外の検出器はそれらの影響を受け
ず、正確に変流器二次電流を測定することができる。"Function" By configuring the present invention as described above, even if the detector is removed when the resistance value of the input resistance of the detector cannot be sufficiently high compared to the resistance value of the resistor, it will not cause malfunctions. Even if the resistance value of the input resistance of a certain detector changes, the other detectors are not affected by the change and can accurately measure the current transformer secondary current.

「実施例」 以下、本発明の実施例を第１図に基づいて詳細に説明す
る。"Example" Hereinafter, an example of the present invention will be described in detail based on FIG.

第１図において、変流器（１）の出力側に複数の抵抗器
（２１，２２，２３、・・・、２ｎ）を直列接続した抵
抗器群を接続する。また、前記各抵抗器（２１，２２，
２３、・・・、２ｎ）両端の出力を検出する差動増幅器
や絶縁形増幅器などの検出器（３１，３２，３３、・・
・、３ｎ）を各抵抗器（２１，２２，２３、・・・、２
ｎ）に対してそれぞれ設けている。In FIG. 1, a resistor group in which a plurality of resistors (21, 22, 23, . . . , 2n) are connected in series is connected to the output side of a current transformer (1). In addition, each of the resistors (21, 22,
23,..., 2n) A detector such as a differential amplifier or an isolated amplifier that detects the output at both ends (31, 32, 33,...
・, 3n) for each resistor (21, 22, 23, . . . , 2
n) respectively.

変流器二次電流は、出力側に接続される負荷抵抗の抵抗
値がその変流器の許容値以下であり、変流器−次電流が
一定であれば、出力側に接続される負荷抵抗の抵抗値に
関係なく一定である。このため、直列接続された抵抗器
（２１，２２，２３、・・・、２ｎ）の抵抗器群の合成
抵抗値を変流器（１）の許容値以下に選ぶことにより、
直列接続された各抵抗器（２１，２２，２３、・・・　
２ｎ）の両端に生じる電圧Ｖｉは、変流器（１）の二次
電流を１２、各抵抗器（２１，２２，２３、・・・、２
ｎ）の抵抗値をＲ２ｒ−、その抵抗器（２１，２２，２
３、・・・　２ｎ）に対してそれぞれ設けた各検出器（
３１，３２，３３、・・　３ｎ）の入力抵抗の抵抗値を
Ｒ３ｉとすると、Ｖｉ−１２ｘＲ２ｉｘＲ３ｉ／　（Ｒ
２ｉ　＋Ｒ３ｉ）か成立する。ただし、１＝１．２、・
・・、ｎである。したがって、各検出器（３１，３２，
３３、・・、３ｎ）は、この各抵抗器（２１，２２，２
３、・・・、２ｎ）の両端に生じる電圧Ｖ１を検出し、
変流器（１）の二次電流を測定することになる。The current transformer secondary current is the load connected to the output side if the resistance value of the load resistor connected to the output side is less than the allowable value of the current transformer and the current transformer secondary current is constant. It is constant regardless of the resistance value of the resistor. Therefore, by selecting the combined resistance value of the resistor group of series-connected resistors (21, 22, 23, ..., 2n) to be less than the allowable value of the current transformer (1),
Each resistor connected in series (21, 22, 23,...
2n), the secondary current of the current transformer (1) is 12, and each resistor (21, 22, 23, . . . , 2
n) resistance value R2r-, its resistor (21, 22, 2
3,...2n) respectively installed for each detector (
31, 32, 33, ... 3n)), if the resistance value of the input resistance is R3i, then Vi-12xR2ixR3i/(R
2i +R3i) holds true. However, 1=1.2,・
..., n. Therefore, each detector (31, 32,
33,..., 3n) are the resistors (21, 22, 2
3, ..., 2n) is detected across the voltage V1,
The secondary current of the current transformer (1) will be measured.

以上から、ある検出器を取外した場合、検出器を取外し
た抵抗器の両端に生じる電圧は変化するが、それ以外の
検出器においては、その影響を受けず、正確に変流器二
次電流を測定することができる。例えば、検出器（３１
）を取外した場合、抵抗器（２１）以外の各抵抗器（２
２，２３、・・・２ｎ）の両端に生じる電圧Ｖｊは変わ
らず、Ｖｊ＝Ｉ２ｘＲ２ｊｘＲ３ｊ／（Ｒ２ｊ＋Ｒ３ｊ
）の関係が成立する。したがって、検出器（３１）以外
の検出器（３２，３３、・・・、３ｎ）では、検出器（
３１）を取外したことによる影響を受けず、正確に変流
器（１）の二次電流を測定することかできる。ただし、
」＝２．３、・・　ｎである。From the above, when a certain detector is removed, the voltage generated across the resistor from which the detector was removed changes, but other detectors are not affected by this and the current transformer secondary current can be measured. For example, the detector (31
) is removed, each resistor (2) except resistor (21)
2, 23, ... 2n) remains unchanged, and Vj=I2xR2jxR3j/(R2j+R3j
) holds true. Therefore, in the detectors (32, 33, ..., 3n) other than the detector (31), the detector (
31) The secondary current of the current transformer (1) can be accurately measured without being affected by the removal of the current transformer (1). however,
”=2.3,...n.

また、ある検出器の故障などによりその検出器の入力抵
抗の抵抗値が変化した場合においても、それ以外の検出
器においては、その影響を受けず、正確に変流器二次電
流を測定することかできる。In addition, even if the resistance value of the input resistance of a certain detector changes due to a failure of that detector, other detectors will not be affected and will accurately measure the current transformer secondary current. I can do it.

例えば、検出器（３１）が故障し、その入力抵抗の抵抗
値が零になった場合、抵抗器（２１）の両端に生じる電
圧ｖ１はＶ１＝０となるか、抵抗器（２１）以外の各抵
抗器（２２，２３、・・・　２ｎ）の両端に生−じる電
圧Ｖ」は変わらず、Ｖ　ｊ　＝　Ｔ　２ｘＲ２ｊｘＲ３
ｊ／　（Ｒ２ｊ十Ｒ３ｊ）の関係か成立する。したがっ
て、検出器（３１）以外の正常な検出器（３２，３３、
・・・　３ｎ）では、検出器（３１）の入力抵抗の抵抗
値の変化による影響を受けず、正確に変流器（１）の二
次電流を測定することができる。For example, if the detector (31) fails and the resistance value of its input resistance becomes zero, the voltage v1 generated across the resistor (21) will be V1 = 0, or The voltage V" generated across each resistor (22, 23, ... 2n) remains unchanged, and V j = T 2 x R 2 j x R 3
The relationship j/ (R2j + R3j) holds true. Therefore, normal detectors (32, 33,
... 3n), it is possible to accurately measure the secondary current of the current transformer (1) without being affected by changes in the resistance value of the input resistance of the detector (31).

「発明の効果」 本発明は、以上説明したように構成されているので、以
下に記載されるような効果を奏する。"Effects of the Invention" Since the present invention is configured as described above, it produces the effects described below.

（イ）検出器の入力抵抗の抵抗値が抵抗器の抵抗値に対
して十分に高くできない場合においても、ある検出器を
取外しても、それ以外の検出器はその影響を受けず、正
確に変流器二次電流を測定することかできる。(b) Even if the resistance value of the input resistance of the detector cannot be sufficiently high compared to the resistance value of the resistor, even if one detector is removed, other detectors will not be affected and the accuracy will be improved. Can measure current transformer secondary current.

（ロ）ある検出器が故障などによりその入力抵抗の抵抗
値が変化した場合であっても、それ以外の正常な検出器
はその影響を受けず、正確に変流器二次電流を測定する
ことができる。(b) Even if the resistance value of the input resistance of a certain detector changes due to a malfunction, other normal detectors will not be affected and will accurately measure the current transformer secondary current. be able to.

（ハ）入力抵抗が低い検出器の使用ができるため、耐ノ
イズ性能の向上が図れる。(c) Since a detector with low input resistance can be used, noise resistance performance can be improved.

【図面の簡単な説明】[Brief explanation of drawings]

第１図は本発明の変流器出力回路を、第２図は従来の変
流器出力回路を示した図である。 図において、（１）は変流器、（２１，２２，２３、・
・・　２ｎ）は抵抗器、（３１，３２，３３、・・・　
３ｎ）は検出器である。 第１図 第２図 特許出願人　株式会社　高岳製作所FIG. 1 shows a current transformer output circuit according to the present invention, and FIG. 2 shows a conventional current transformer output circuit. In the figure, (1) is a current transformer, (21, 22, 23,
2n) is a resistor, (31, 32, 33,...
3n) is a detector. Figure 1 Figure 2 Patent applicant Takatake Seisakusho Co., Ltd.

Claims (1)

【特許請求の範囲】[Claims] 変流器（１）の出力側に複数の抵抗器（２１、２２、２
３、・・・、２ｎ）を直列接続した抵抗器群を接続し、
前記各抵抗器（２１、２２、２３、・・・、２ｎ）両端
の出力を検出する検出器（３１、３２、３３、・・・、
３ｎ）を各抵抗器（２１、２２、２３、・・・、２ｎ）
に対してそれぞれ設けたことを特徴とする変流器出力回
路。A plurality of resistors (21, 22, 2) are connected to the output side of the current transformer (1).
3, ..., 2n) connected in series,
Detectors (31, 32, 33, . . . ,
3n) to each resistor (21, 22, 23,..., 2n)
A current transformer output circuit characterized by being provided for each of the current transformer output circuits.
JP2251963A 1990-09-25 1990-09-25 Current transformer output circuit Expired - Lifetime JP2701524B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2251963A JP2701524B2 (en) 1990-09-25 1990-09-25 Current transformer output circuit

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP2251963A JP2701524B2 (en) 1990-09-25 1990-09-25 Current transformer output circuit

Publications (2)

Publication Number Publication Date
JPH04131768A true JPH04131768A (en) 1992-05-06
JP2701524B2 JP2701524B2 (en) 1998-01-21

Family

ID=17230594

Family Applications (1)

Application Number Title Priority Date Filing Date
JP2251963A Expired - Lifetime JP2701524B2 (en) 1990-09-25 1990-09-25 Current transformer output circuit

Country Status (1)

Country Link
JP (1) JP2701524B2 (en)

Also Published As

Publication number Publication date
JP2701524B2 (en) 1998-01-21

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