JPH0379934B2 - - Google Patents
Info
- Publication number
- JPH0379934B2 JPH0379934B2 JP61281796A JP28179686A JPH0379934B2 JP H0379934 B2 JPH0379934 B2 JP H0379934B2 JP 61281796 A JP61281796 A JP 61281796A JP 28179686 A JP28179686 A JP 28179686A JP H0379934 B2 JPH0379934 B2 JP H0379934B2
- Authority
- JP
- Japan
- Prior art keywords
- circuit
- detection
- phase
- voltage
- resistor
- 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
- 238000001514 detection method Methods 0.000 claims description 35
- 230000005284 excitation Effects 0.000 claims description 24
- 230000008878 coupling Effects 0.000 claims description 18
- 238000010168 coupling process Methods 0.000 claims description 18
- 238000005859 coupling reaction Methods 0.000 claims description 18
- 239000003990 capacitor Substances 0.000 claims description 13
- 230000007935 neutral effect Effects 0.000 claims description 4
- 238000005259 measurement Methods 0.000 description 12
- 230000001681 protective effect Effects 0.000 description 4
- 230000000694 effects Effects 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 238000009413 insulation Methods 0.000 description 2
- 230000035945 sensitivity Effects 0.000 description 2
- 230000002159 abnormal effect Effects 0.000 description 1
- 230000005856 abnormality Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000004804 winding Methods 0.000 description 1
Landscapes
- Protection Of Generators And Motors (AREA)
- Testing Of Short-Circuits, Discontinuities, Leakage, Or Incorrect Line Connections (AREA)
- Emergency Protection Circuit Devices (AREA)
Description
【発明の詳細な説明】
〔産業上の利用分野〕
本発明は三相交流励磁回路の地絡検出装置に関
する。DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a ground fault detection device for a three-phase AC excitation circuit.
従来の励磁回路の地絡検出装置として、特開昭
56−82458号で提案されている直流励磁回路の地
絡検出装置があり、保護リレー番号64Eとして多
く用いられている。これは地絡被検出回路の負極
性側と大地間に、保護抵抗Ｒ１、直流電源Ｅおよ
び検出抵抗ｒを結合し、地絡被検出回路の負極性
側で例えば等価抵抗Reで地絡を生じた時に、こ
の検出回路に、Ｅ／（R1＋ｒ＋Re）なる直流電
流ｉが流れ、その結果、検出抵抗ｒの両端にｉ×
ｒ＝Ｅ・ｒ／（R1＋ｒ＋Re）なる電圧ｖが生ず
るので、ある値以下の抵抗Reに対して電圧ｖで
作動する保護リレーを検出抵抗ｒの両端に結合し
ておくことにより、Re以下の抵抗となる地絡が
検出可能であつた。
As a conventional excitation circuit ground fault detection device,
There is a ground fault detection device for a DC excitation circuit proposed in No. 56-82458, which is often used as a protective relay number 64E. This connects a protective resistor R1, a DC power supply E, and a detection resistor r between the negative polarity side of the circuit to be detected for a ground fault and the ground, and generates a ground fault with an equivalent resistance Re on the negative polarity side of the circuit to be detected for a ground fault. At this time, a DC current i of E/(R1+r+Re) flows through this detection circuit, and as a result, i×
Since a voltage v of r=E・r/(R1+r+Re) is generated, by connecting a protective relay that operates with voltage v to both ends of the detection resistor r for a resistance Re below a certain value, the resistance below Re It was possible to detect a ground fault.
また直流励磁回路の負極と正極の途中、または
正極側で同じ抵抗値Reで地絡を生じたときは、
上記検出用電圧Ｅに更に直列に同方向の直流電圧
が加わることになるので、その場合にも同様に設
定電圧を超える電圧降下が検出抵抗の両端に生
じ、結局Re以下の抵抗値でのいかなる位置での
地絡も検出が可能である。 Also, if a ground fault occurs between the negative and positive poles of the DC excitation circuit or on the positive pole side with the same resistance value Re,
Since a DC voltage in the same direction is further applied in series to the detection voltage E, in that case as well, a voltage drop exceeding the set voltage will occur across the detection resistor. It is also possible to detect ground faults at certain locations.
しかし、上記の地絡検出装置は、直流励磁回路
に限定され、三相交流回路では励磁回路の電圧極
性が時間的に変化し、検出電圧Ｅを打消す方向の
ときも生ずるため、一様な検出レベルの整定が不
可能である。
However, the above ground fault detection device is limited to DC excitation circuits, and in three-phase AC circuits, the voltage polarity of the excitation circuit changes over time, and this occurs even when the voltage polarity in the excitation circuit cancels out the detected voltage E. It is impossible to set the detection level.
本発明の目的は、三相交流励磁回路の地絡検出
を可能とし、安全で高精度の検出感度を得ること
のできる三相交流励磁回路の地絡検出回路を提供
するにある。 An object of the present invention is to provide a ground fault detection circuit for a three-phase AC excitation circuit that can detect a ground fault in a three-phase AC excitation circuit and can provide safe and highly accurate detection sensitivity.
本発明は、三相交流回路の中性点と大地間に、
結合用コンデンサ、高周波電源および検出用抵抗
を直列に結合し、上記三相交流回路の中性点と大
地間の電気的定数と等価な測定用ブリツヂ回路を
設け、この測定用ブリツヂ回路に上記高周波電源
によつて検出用電圧を与えるようにしたことを特
徴としている。
The present invention provides a connection between the neutral point of a three-phase AC circuit and the ground.
A coupling capacitor, a high-frequency power source, and a detection resistor are coupled in series to provide a measurement bridge circuit equivalent to the electrical constant between the neutral point of the three-phase AC circuit and the ground, and this measurement bridge circuit is connected to the high-frequency It is characterized in that the detection voltage is supplied by the power supply.
上述の如き構成によれば、三相交流回路と検出
回路間に高耐圧の結合用コンデンサを用いている
ため、常時あるいは異常時の電圧に対しても十分
絶縁でき、一方、地絡検出のための高周波電流に
対しては低インピーダンスとなつて十分な交流結
合を行なうことができ、また高周波電源は三相交
流の基本周波数と、それを供給するサイリスタコ
ンバータ等の一次側電源周波数のいずれよりも十
分高く、かつコンバータから発生する高周波電源
の主な周波数を避けたものとすることにより、検
出用高周波電流のみで選択測定が可能となる。ま
た測定用ブリツヂ回路によつて三相交流励磁回路
と大地間の迷路静電容量を流れる電流による測定
誤差の発生を防止して高精度の検出感度を得るこ
とができる。
According to the above-mentioned configuration, since a high-voltage coupling capacitor is used between the three-phase AC circuit and the detection circuit, it can be sufficiently insulated against constant or abnormal voltage. It has a low impedance for the high-frequency current of By setting the frequency to be sufficiently high and avoiding the main frequency of the high-frequency power source generated from the converter, selective measurement can be performed using only the high-frequency detection current. Furthermore, the measurement bridge circuit prevents measurement errors caused by current flowing through the labyrinth capacitance between the three-phase AC excitation circuit and the ground, thereby providing highly accurate detection sensitivity.
以下本発明の実施例を図面によつて説明する。 Embodiments of the present invention will be described below with reference to the drawings.
三相交流励磁回路１は地絡検出の対象であり、
サイリスタコンバータ２および三相交流電源３が
励磁装置および電源となつている。結合コンデン
サ４は三相交流励磁回路１と検出回路７を交流結
合すると共に絶縁を兼ねた高耐電圧コンデンサで
ある。高周波電源５および結合トランス６は、検
出回路７と測定用ブリツヂ回路８の両方に検出用
電圧を印加する電源である。この高周波電源６と
大地間の検出抵抗９は三相交流励磁回路１に地絡
を生じて検出回路７に高周波電流ｉが流れたとき
両端に電圧降下の変化を生じさせるための抵抗で
ある。ブリツヂ用結合コンデンサ１０は、結合コ
ンデンサ４と同じ静電容量で低耐電圧用である。
三相交流励磁回路１のコンデンサ１１と抵抗１２
は、それぞれ三相交流励磁回路１の迷路静電容量
と絶縁抵抗を表わし、測定用ブリツヂ回路８のコ
ンデンサ１３と可変抵抗１４は、交流ブリツヂの
平衡をとるためのもので、可変抵抗１４はブリツ
ヂの平衡をとることができるよう微調整可能であ
る。また抵抗１５は検出用抵抗９と同じ抵抗値で
あり、三相交流励磁回路１と大地間の電気的定数
は、測定用ブリツヂ回路８のそれと同じに成され
ている。 The three-phase AC excitation circuit 1 is subject to ground fault detection,
Thyristor converter 2 and three-phase AC power supply 3 serve as an excitation device and power supply. The coupling capacitor 4 is a high withstand voltage capacitor that AC couples the three-phase AC excitation circuit 1 and the detection circuit 7 and also serves as insulation. The high frequency power supply 5 and the coupling transformer 6 are power supplies that apply a detection voltage to both the detection circuit 7 and the measurement bridge circuit 8. The detection resistor 9 between the high frequency power supply 6 and the ground is a resistor for causing a change in voltage drop across both ends when a ground fault occurs in the three-phase AC excitation circuit 1 and high frequency current i flows through the detection circuit 7. The bridge coupling capacitor 10 has the same capacitance as the coupling capacitor 4 and is for low withstand voltage.
Capacitor 11 and resistor 12 of three-phase AC excitation circuit 1
represent the maze capacitance and insulation resistance of the three-phase AC excitation circuit 1, respectively. The capacitor 13 and variable resistor 14 of the measurement bridge circuit 8 are for balancing the AC bridge; can be finely adjusted to achieve a balance. The resistor 15 has the same resistance value as the detection resistor 9, and the electrical constant between the three-phase AC excitation circuit 1 and the ground is the same as that of the measurement bridge circuit 8.
整流器１６は抵抗９，１５間の高周波電位差を
直流に変化する。電圧計１７とリレー１８は地絡
によつて生ずる交流ブリツヂの不平衡電圧を測定
検出するものであり、抵抗１９とコンデンサ２０
は、地絡検出用の高周波電流の周波数に対して電
圧計１７とフオトカプラー２１の動作に必要な直
流電圧を得るよう時定数C1×R1を定める。フオ
トカプラー２１は更に検出回路７と保護リレー回
路２２を絶縁し、三相交流励磁回路１から保護リ
レー回路２２を二重に絶縁して安全性と信頼性を
高めている。尚、フオトカプラー２１以降の保護
リレー回路は周知の技術であり説明を省略する。
結合トランス２３は、整流器１６と測定用ブリツ
ヂ回路８を電磁的に結合しており、その二次側つ
まり整流器１６側は結合トランス２３の二次巻線
のインダクタンスとコンデンサ２４とにより、検
出用高周波電流に対してのみ並列共振を生じて高
い電圧を発生する。 The rectifier 16 changes the high frequency potential difference between the resistors 9 and 15 into direct current. The voltmeter 17 and relay 18 measure and detect the unbalanced voltage of the AC bridge caused by a ground fault, and the resistor 19 and capacitor 20
The time constant C 1 ×R 1 is determined so as to obtain the DC voltage necessary for the operation of the voltmeter 17 and the photocoupler 21 with respect to the frequency of the high-frequency current for ground fault detection. The photocoupler 21 further insulates the detection circuit 7 and the protection relay circuit 22, and double-insulates the protection relay circuit 22 from the three-phase AC excitation circuit 1 to improve safety and reliability. Note that the protective relay circuit after the photocoupler 21 is a well-known technology, and its explanation will be omitted.
The coupling transformer 23 electromagnetically couples the rectifier 16 and the bridge circuit 8 for measurement, and the secondary side thereof, that is, the rectifier 16 side, receives high frequency signals for detection by the inductance of the secondary winding of the coupling transformer 23 and the capacitor 24. Generates high voltage by creating parallel resonance only with respect to current.
使用時においては、可変抵抗１４を調整して測
定用ブリツヂ回路８の交流ブリツヂの平衡をと
る。これによつて結合トランス２３の一次側は同
電位となり、二次側には電圧を発生せず、従つて
電圧計１７も振れず、また保護リレー１８も動作
しない。 In use, the variable resistor 14 is adjusted to balance the AC bridge of the measurement bridge circuit 8. As a result, the primary side of the coupling transformer 23 has the same potential, and no voltage is generated on the secondary side, so the voltmeter 17 does not swing and the protection relay 18 does not operate.
異常時においては、三相交流励磁回路１のいず
れかの位置で地絡が生ずると、測定用ブリツヂ回
路８の不平衡電圧を生じ、そのうち検出用高周波
電流の成分だけが結合トランス２３の二次側に発
生し、電圧計１７と保護リレー１８が作動して地
絡を検出する。 In the event of an abnormality, if a ground fault occurs at any position in the three-phase AC excitation circuit 1, an unbalanced voltage will be generated in the measurement bridge circuit 8, of which only the detection high-frequency current component will be transferred to the secondary of the coupling transformer 23. The voltmeter 17 and protection relay 18 operate to detect a ground fault.
前述したように、結合トランス２３の二次側は
図示の構成に限らず周知の構成によつて電圧計１
７やリレー１８等の検知部を得ることができる。 As mentioned above, the secondary side of the coupling transformer 23 is not limited to the configuration shown in the drawings, but can be configured to
7, relay 18, etc. can be obtained.
以上説明したように本発明によれば、高耐電圧
の結合コンデンサを用いているため、検出回路を
三相交流励磁回路に対して絶縁が十分でき安全で
あり、また三相交流励磁回路のいかなる位置にお
ける地絡も三相交流電圧の状態の関係なく一定の
精度で検出測定できる。
As explained above, according to the present invention, since a high withstand voltage coupling capacitor is used, the detection circuit can be sufficiently insulated from the three-phase AC excitation circuit, making it safe. Ground faults at any location can also be detected and measured with constant accuracy regardless of the state of the three-phase AC voltage.
図面は本発明の一実施例による三相交流励磁回
路の地絡検出装置を示す回路図である。
１……三相交流励磁回路、４……結合コンデン
サ、５……高周波電源、６……結合トランス、８
……測定用ブリツヂ回路、９……検出抵抗、２３
……結合トランス。
The drawing is a circuit diagram showing a ground fault detection device for a three-phase AC excitation circuit according to an embodiment of the present invention. 1...Three-phase AC excitation circuit, 4...Coupling capacitor, 5...High frequency power supply, 6...Coupling transformer, 8
...Measurement bridge circuit, 9...Detection resistor, 23
...Coupling transformer.
Claims (1)
電圧の結合コンデンサ、高周波電源および検出用
抵抗を直列に接続し、上記中性点と大地間の電気
的定数と等価で、しかも上記高周波電源によつて
検出用電圧を得る測定用ブリツヂ回路を設け、こ
の測定用ブリツヂ回路における上記検出用抵抗と
等しい抵抗値の抵抗と上記検出用抵抗との間に結
合トランスを接続し、この結合トランスの二次側
に検知部を構成したことを特徴とする三相交流励
磁回路の地絡検出装置。1. A high-withstand voltage coupling capacitor, a high-frequency power source, and a detection resistor are connected in series between the neutral point of the three-phase AC excitation circuit and the ground, and the electric constant between the neutral point and the ground is equivalent to the above, and A measuring bridge circuit that obtains a detection voltage from the high frequency power supply is provided, a coupling transformer is connected between the detecting resistor and a resistor having a resistance equal to that of the detecting resistor in the measuring bridge circuit, and the detecting resistor is connected to the measuring bridge circuit. A ground fault detection device for a three-phase AC excitation circuit, characterized in that a detection section is configured on the secondary side of a coupling transformer.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61281796A JPS63136922A (en) | 1986-11-28 | 1986-11-28 | Grounding detector of three-phase ac exciting circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61281796A JPS63136922A (en) | 1986-11-28 | 1986-11-28 | Grounding detector of three-phase ac exciting circuit |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS63136922A JPS63136922A (en) | 1988-06-09 |
| JPH0379934B2 true JPH0379934B2 (en) | 1991-12-20 |
Family
ID=17644098
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP61281796A Granted JPS63136922A (en) | 1986-11-28 | 1986-11-28 | Grounding detector of three-phase ac exciting circuit |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS63136922A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP6438729B2 (en) * | 2014-10-17 | 2018-12-19 | 新日本無線株式会社 | Insulation performance diagnostic device and method of setting capacitance value of pseudo capacitor |
-
1986
- 1986-11-28 JP JP61281796A patent/JPS63136922A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS63136922A (en) | 1988-06-09 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EXPY | Cancellation because of completion of term |