JPH0619406B2 - Ground fault detection method - Google Patents
Ground fault detection methodInfo
- Publication number
- JPH0619406B2 JPH0619406B2 JP63224028A JP22402888A JPH0619406B2 JP H0619406 B2 JPH0619406 B2 JP H0619406B2 JP 63224028 A JP63224028 A JP 63224028A JP 22402888 A JP22402888 A JP 22402888A JP H0619406 B2 JPH0619406 B2 JP H0619406B2
- Authority
- JP
- Japan
- Prior art keywords
- ground fault
- current
- supply line
- signal
- load
- 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
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- Emergency Protection Circuit Devices (AREA)
- Testing Of Short-Circuits, Discontinuities, Leakage, Or Incorrect Line Connections (AREA)
- Locating Faults (AREA)
Description
【発明の詳細な説明】 （産業上の利用分野） この発明は、直流電源と、負荷と、前記直流電源と負荷
を結ぶ供給線とから構成される直流回路の地絡を検出す
る地絡検出方法に関するものである。Description: TECHNICAL FIELD The present invention relates to a ground fault detection for detecting a ground fault of a DC circuit composed of a DC power source, a load, and a supply line connecting the DC power source and the load. It is about the method.
（従来の技術） 従来から、直流回路を使用している発電所，変電所，プ
ラントでは、設置されている例えば直流モータ等の負荷
の地絡を検出して、漏洩電流の防止を図っている。この
地絡の検出方法として第５図に示すブリッジ回路を用い
る方法が知られている。図において、１は直流電源、２
は地絡検出回路、３は直流電源１のプラス線、４は直流
電源１のマイナス線、５は負荷である。地絡検出回路２
は、抵抗Ｒ１，Ｒ２，Ｒ３、リレーＲyによるブリッジ
回路からなっており、抵抗Ｒ１，Ｒ２はプラス供給線３
とマイナス供給線４との間で直列回路を構成しており、
抵抗Ｒ３の一側は抵抗Ｒ１，Ｒ２の接続点に接続され、
リレーＲyの他側は接地されている。Ｒxは地絡抵抗であ
る。(Prior Art) Conventionally, in a power plant, a substation, or a plant that uses a DC circuit, a ground fault of a load such as a DC motor installed is detected to prevent a leakage current. . As a method of detecting this ground fault, a method using a bridge circuit shown in FIG. 5 is known. In the figure, 1 is a DC power source, 2
Is a ground fault detection circuit, 3 is a plus line of the DC power supply 1, 4 is a minus line of the DC power supply 1, and 5 is a load. Ground fault detection circuit 2
Is a bridge circuit including resistors R 1 , R 2 and R 3 and a relay Ry. The resistors R 1 and R 2 are positive supply lines 3
And a negative supply line 4 form a series circuit,
One side of the resistor R 3 is connected to the connection point of the resistors R 1 and R 2 ,
The other side of the relay Ry is grounded. Rx is a ground resistance.
負荷５に地絡が生じていないときはＲxは漏洩抵抗に相
当し、大きい値となるためリレーＲyに流れる電流はほ
ぼゼロである。When there is no ground fault in the load 5, Rx corresponds to a leakage resistance and has a large value, so that the current flowing through the relay Ry is almost zero.
負荷５の中性点近傍以外に地絡が生じると、ブリッジの
平衡がくずれてリレーＲyに電流が流れる。これにより
リレーＲyが作動して地絡が検出される。これは、供給
線で地絡が生じても同様に検出することができる。When a ground fault occurs other than near the neutral point of the load 5, the bridge is out of balance and a current flows through the relay Ry. As a result, the relay Ry operates and a ground fault is detected. This can be similarly detected even if a ground fault occurs in the supply line.
（発明が解決しようとする課題） しかしながら、上記の地絡検出方法にあっては、負荷５
の中性点近傍で地絡が発生した場合、ブリッジの平衡の
くずれは小さいので、リレーＲyに流れる電流は微弱で
あり、第６図に示すように、負荷５の中性点近傍でリレ
ーＲyの不動作域が生じ、中性点近傍の地絡を検出する
ことができないという問題があった。また、直流電源内
部で地絡が生じた場合も同様な問題があった。(Problems to be Solved by the Invention) However, in the above ground fault detection method, the load 5
When a ground fault occurs in the vicinity of the neutral point of, the current in the relay Ry is weak because the collapse of the balance of the bridge is small, and as shown in FIG. There was a problem that the ground fault near the neutral point could not be detected due to the non-operation area. Further, there is a similar problem when a ground fault occurs inside the DC power supply.
（発明の目的） そこで、この発明は、上記の事情に鑑みてなされたもの
で、その目的とするところは、直流回路の地絡点位置に
拘りなくその地絡を検出することのできる地絡検出方法
を提供することにある。(Object of the invention) Therefore, the present invention has been made in view of the above circumstances, and an object thereof is to detect a ground fault regardless of the position of the ground fault of the DC circuit. It is to provide a detection method.
（課題を解決するための手段） この発明は、上記目的を達成するために、直流電源と、
負荷と、前記直流電源と負荷を結ぶ供給線とから構成さ
れる直流回路の地絡を検出する地絡検出方法であって、 前記供給線と大地間に交流信号を注入して、該供給線に
流れる交流電流を検出するとともに、大地に対する供給
線の交流電圧を検出し、これら検出した交流電流および
交流電圧から直流回路の地絡を検出するようにしたもの
である。(Means for Solving the Problems) In order to achieve the above object, the present invention provides a DC power supply,
A ground fault detection method for detecting a ground fault of a DC circuit composed of a load and a supply line connecting the DC power supply and the load, wherein an AC signal is injected between the supply line and the ground, In addition to detecting the AC current flowing in the ground, the AC voltage of the supply line to the ground is detected, and the ground fault of the DC circuit is detected from the detected AC current and AC voltage.
（作 用） この発明に係る地絡検出方法によれば、直流回路の地絡
点位置に拘らず、供給線に流れる交流信号の信号電流お
よび信号電圧を検出することができ、この信号電流およ
び信号電圧から地絡が検出される。(Operation) According to the ground fault detection method of the present invention, it is possible to detect the signal current and the signal voltage of the AC signal flowing in the supply line regardless of the position of the ground fault point of the DC circuit. A ground fault is detected from the signal voltage.
（実施例） 以下に、この発明に拘る地絡検出方法を直流モータに適
用した実施例について図面を参照しつつ説明する。(Embodiment) An embodiment in which the ground fault detection method according to the present invention is applied to a DC motor will be described below with reference to the drawings.
第１図において、１１は直流電源で、Ｐはその陽極、Ｎ
はその陰極である。１２は直流電源１１の陽極Ｐに接続
されたプラス供給線、１３は直流電源１１の陰極Ｎに接
続されたマイナス供給線、１４は供給線１２，１３に接
続された直流モータ(負荷)で、ここでは等価回路として
示してある。In FIG. 1, 11 is a DC power source, P is its anode, N
Is its cathode. 12 is a positive supply line connected to the anode P of the DC power supply 11, 13 is a negative supply line connected to the cathode N of the DC power supply 11, 14 is a DC motor (load) connected to the supply lines 12 and 13, Here, it is shown as an equivalent circuit.
１５は信号注入部で、これは、コンデンサ１６，１７と
交流信号を出力する交流電源１８とからなっており、コ
ンデンサ１６，１７はプラス供給線１２とマイナス供給
線１３との間で直列回路を構成しており、交流電源１８
の一方の出力端子がコンデンサ１６，１７の接続点に接
続され、交流電源１８の他方の出力端子が接地されて、
交流電源１８による交流信号がプラス供給線１２とマイ
ナス供給線１３とに注入されるようになっている。Reference numeral 15 is a signal injection unit, which comprises capacitors 16 and 17 and an AC power supply 18 that outputs an AC signal. The capacitors 16 and 17 form a series circuit between the positive supply line 12 and the negative supply line 13. AC power source 18
One output terminal is connected to the connection point of the capacitors 16 and 17, and the other output terminal of the AC power supply 18 is grounded,
An AC signal from the AC power supply 18 is injected into the plus supply line 12 and the minus supply line 13.
２０は信号検出部で、これは、変流器２１とコンデンサ
２２とからなっており、変流器２１にはプラス供給線１
２とマイナス供給線１３とを重ねて設置し、負荷１４に
流れる直流成分を相殺して交流信号の信号電流だけが検
出されるようになっている。コンデンサ２２はマイナス
供給線１３に接続され、直流電圧をカットしてマイナス
供給線１３に流れる交流信号の信号電圧を検出するため
のものである。なお、このコンデンサ２２はプラス供給
線１２に接続してプラス供給線１２の信号電圧を検出す
るようにしてもよい。Reference numeral 20 denotes a signal detection unit, which includes a current transformer 21 and a capacitor 22, and the current transformer 21 has a positive supply line 1
2 and the minus supply line 13 are arranged in an overlapping manner so that the DC component flowing in the load 14 is canceled and only the signal current of the AC signal is detected. The capacitor 22 is connected to the minus supply line 13 and cuts the DC voltage to detect the signal voltage of the AC signal flowing through the minus supply line 13. The capacitor 22 may be connected to the positive supply line 12 to detect the signal voltage of the positive supply line 12.
２３はコンデンサ２２を介して検出される信号電圧と、
変流器２１が検出する信号電流との位相差を求め、この
位相差や信号電流および信号電圧等から地絡を判定する
判定装置である。２４は漏洩抵抗、２５は対地静電容量
である。23 is a signal voltage detected via the capacitor 22,
This is a determination device that determines a phase difference from the signal current detected by the current transformer 21 and determines a ground fault from the phase difference, the signal current, the signal voltage, and the like. Reference numeral 24 is a leakage resistance, and 25 is a ground capacitance.
いま、直流電源１１から直流電流が負荷１４に供給さ
れ、交流電源１８によって交流信号がプラス供給線１２
とマイナス供給線１３とに注入されると、変流器２１が
プラス供給線１２とマイナス供給線１３とに流れる交流
信号の信号電流を検出し、コンデンサ２２がマイナス供
給線１３に流れる交流信号の信号電圧を検出する。Now, a DC current is supplied from the DC power supply 11 to the load 14, and an AC signal is supplied to the load 14 by the AC power supply 18.
And the negative supply line 13, the current transformer 21 detects the signal current of the alternating current signal flowing through the positive supply line 12 and the negative supply line 13, and the capacitor 22 detects the alternating current signal flowing through the negative supply line 13. Detect the signal voltage.
ところで、交流電源１８から流れでる電流は、地絡抵抗
Ｒxと対地静電容量２５を流れる電流とを合わせたもの
であり、負荷１４に地絡が生じていないときは、地絡抵
抗Ｒxは対地漏洩抵抗２４だけとなり大きな値となる。
このため、交流電源１８から流れる信号電流Ｉ１は大部
分が対地静電容量２５に流れる電流となり、第２図の
(Ａ)に示すように、交流電源電圧Ｅに対し９０゜近く位
相が進んだ値となる。By the way, the current flowing from the AC power supply 18 is a combination of the ground fault resistance Rx and the current flowing through the ground capacitance 25. When the load 14 is not grounded, the ground fault resistance Rx is grounded. Only the leakage resistance 24 becomes a large value.
Therefore, most of the signal current I 1 flowing from the AC power supply 18 is a current flowing to the ground capacitance 25, and the signal current I 1 shown in FIG.
As shown in (A), the phase advances by about 90 ° with respect to the AC power supply voltage E.
一方、値絡が生じると、対地静電容量２５に流れる電流
Ｉ１に地絡抵抗Ｒxに流れる電流Ｉ２が重畳することに
なる。この電流Ｉ２は交流電源電圧Ｅと同相なので、地
絡が生じた場合の信号電流Ｉ３（＝Ｉ１＋Ｉ２）は第２
図の(Ａ)に示すように、交流電源電圧Ｅとの位相差が小
さくなる。On the other hand, when the value fault occurs, so that the current I 2 flowing in the current I 1 flowing through the earth capacitance 25 to ground fault resistor Rx is superimposed. Since this current I 2 is in phase with the AC power supply voltage E, the signal current I 3 (= I 1 + I 2 ) when a ground fault occurs is the second
As shown in (A) of the figure, the phase difference from the AC power supply voltage E becomes small.
判定装置２３は、求めた位相差と予め設定した設定位相
差とを比較し、その求めた位相差が設定位相差に達した
とき地絡と判定する。The determination device 23 compares the obtained phase difference with a preset phase difference, and when the obtained phase difference reaches the set phase difference, determines that there is a ground fault.
ところで、地絡が発生すると等価回路は第２図の(Ｂ)に
示すようになる。By the way, when a ground fault occurs, the equivalent circuit becomes as shown in FIG.
ここで、交流電源１８からみたコンデンサ２５と地絡抵
抗Ｒxのインピーダンスをとすると、交流電源１８の
電流および電圧と、検出地点における検出電流および検
出電圧とが同じ値とみなすことができることにより、 ＝|／|(cosθ＋jsinθ) となる。ただし、θは交流電圧と交流電流との位相
差である。Here, when the impedance of the capacitor 25 and the ground fault resistance Rx viewed from the AC power supply 18 is set, the current and voltage of the AC power supply 18 can be regarded as the same value as the detection current and the detection voltage at the detection point. | / | (Cos θ + j sin θ) However, θ is the phase difference between the AC voltage and the AC current.
したがって、Ｒx＝|／|cosθである。Therefore, Rx = | / | cos θ.
そして、はコンデンサ２２により交流信号の信号電圧
として検出することができ、は変流器２１によって交
流信号の交流電流として検出するこたができる。またco
sθは位相計にて測定可能である。したがって、Ｒxを算
出することは可能であり、このＲxから地絡を検出する
ことができる。The capacitor 22 can be detected as a signal voltage of an AC signal, and the current transformer 21 can be detected as an AC current of an AC signal. Also co
sθ can be measured with a phase meter. Therefore, it is possible to calculate Rx, and the ground fault can be detected from this Rx.
第３図は第１図の簡略化した等価回路を示したものであ
る。負荷１４のインピーダンスは一般にＲxに比べて十
分に小さいため、第３図に示すように、地絡抵抗Ｒxが
小さなものである限り、負荷１４の地絡点１４ｐの位置
に拘らず、交流電源１８から見たインピーダンスは小さ
く、交流電源１８によって、供給線１２，１３に大きな
交流信号を流すことができる。したがって、負荷１４の
中性地点近傍が地絡しても、各供給線１２，１３に大き
な交流信号が流れるので、その地絡を確実に検出するこ
ができる。FIG. 3 shows a simplified equivalent circuit of FIG. Since the impedance of the load 14 is generally sufficiently smaller than Rx, as shown in FIG. 3, as long as the ground fault resistance Rx is small, the AC power supply 18 is irrespective of the position of the ground fault point 14p of the load 14. The impedance seen from the above is small, and a large AC signal can be supplied to the supply lines 12 and 13 by the AC power supply 18. Therefore, even if the load 14 has a ground fault near the neutral point, a large AC signal flows through each of the supply lines 12 and 13, so that the ground fault can be reliably detected.
第４図は、負荷１４の地絡地点１４ｐと検出領域の関係
を示したものであり、この図から明らかなように、地絡
抵抗Ｒxが所定以下であれば、負荷１４の地絡地点に拘
りなく地絡を検出するこができることを示している。な
お、地絡抵抗Ｒxが所定以上のとき、地絡を検出するこ
とはできないが、この場合の漏洩電流は微弱であるから
差支えない。FIG. 4 shows the relationship between the ground fault point 14p of the load 14 and the detection area. As is clear from this figure, if the ground fault resistance Rx is less than or equal to a predetermined value, the ground fault point of the load 14 is detected. It shows that the ground fault can be detected without concern. When the ground fault resistance Rx is equal to or more than a predetermined value, the ground fault cannot be detected, but the leakage current in this case is weak, which is acceptable.
なお、上記実施例は、負荷の地絡を検出する場合につい
て説明したが、信号電流を検出するための変流器２１を
信号電圧を注入する注入点より直流電源側に設置すれ
ば、一般の直流電源や太陽電池などの直流発電設備の地
絡を検出することも可能である。Although the above embodiment has described the case of detecting the ground fault of the load, if the current transformer 21 for detecting the signal current is installed on the DC power supply side from the injection point for injecting the signal voltage, it is common. It is also possible to detect a ground fault in a DC power generation facility such as a DC power source or a solar cell.
また、上記実施例では、一つの変流器２１を使用してい
るが、複数個の変流器を何箇所かに設置すれば地絡点の
場所を判定することができる。Further, in the above embodiment, one current transformer 21 is used, but the location of the ground fault can be determined by installing a plurality of current transformers at some places.
（発明の効果） この発明によれば、負荷の地絡点位置に拘りなくその地
絡を確実に検出することができ、負荷の漏洩電流の防止
を図ることができる。(Effect of the Invention) According to the present invention, the ground fault can be reliably detected regardless of the position of the ground fault point of the load, and the leakage current of the load can be prevented.
第１図はこの発明に係る地絡検出方法を直流モータを駆
動させる直流回路に適用した実施例の回路図、 第２図の(Ａ)は信号電流と信号電圧との位相関係を示し
た説明図、 第２図の(Ｂ)は地絡が発生した際の等価回路を示した回
路図、 第３図は第１図に示す回路図の簡略化した等価回路図、 第４図は地絡地点と検出領域の関係を示した説明図、 第５図は従来の地絡検出方法を示した説明図、 第６図は従来の地絡検出方法の問題点を示した説明図で
ある。 １１……直流電源 １２……プラス供給線 １３……マイナス供給線 １８……交流電源 ２１……変流器 ２２……コンデンサ ２３……判定装置FIG. 1 is a circuit diagram of an embodiment in which the ground fault detection method according to the present invention is applied to a direct current circuit for driving a direct current motor, and FIG. 2 (A) is an explanation showing a phase relationship between a signal current and a signal voltage. Fig. 2 (B) is a circuit diagram showing an equivalent circuit when a ground fault occurs, Fig. 3 is a simplified equivalent circuit diagram of the circuit diagram shown in Fig. 1, and Fig. 4 is a ground fault. FIG. 5 is an explanatory diagram showing the relationship between points and detection areas, FIG. 5 is an explanatory diagram showing a conventional ground fault detection method, and FIG. 6 is an explanatory diagram showing problems with the conventional ground fault detection method. 11 ... DC power supply 12 ... Positive supply line 13 ... Negative supply line 18 ... AC power supply 21 ... Current transformer 22 ... Capacitor 23 ... Judgment device
Claims (1)
を結ぶ供給線とから構成される直流回路の地絡を検出す
る地絡検出方法であって、 前記供給線と大地間に交流信号を注入して、該供給線に
流れる交流電流を検出するとともに、大地に対する供給
線の交流電圧を検出し、 この検出した交流電流と交流電圧の位相差を求め、この
求めた位相差と予め設定した値とを比較して地絡を検出
することを特徴とする地絡検出方法。1. A ground fault detection method for detecting a ground fault of a direct current circuit comprising a direct current power source, a load, and a supply line connecting the direct current power source and the load, wherein an alternating current between the supply line and the ground. A signal is injected to detect the AC current flowing in the supply line, the AC voltage of the supply line with respect to the ground is detected, and the phase difference between the detected AC current and the AC voltage is calculated. A ground fault detection method comprising detecting a ground fault by comparing with a set value.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63224028A JPH0619406B2 (en) | 1988-09-07 | 1988-09-07 | Ground fault detection method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63224028A JPH0619406B2 (en) | 1988-09-07 | 1988-09-07 | Ground fault detection method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0271168A JPH0271168A (en) | 1990-03-09 |
| JPH0619406B2 true JPH0619406B2 (en) | 1994-03-16 |
Family
ID=16807458
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP63224028A Expired - Lifetime JPH0619406B2 (en) | 1988-09-07 | 1988-09-07 | Ground fault detection method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0619406B2 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5326078A (en) * | 1993-07-08 | 1994-07-05 | Benkan Corporation | Metal diaphragm valve |
| US9297862B2 (en) * | 2011-07-28 | 2016-03-29 | Eaton Corporation | Systems and apparatus for fault detection in DC power sources using AC residual current detection |
| JP7158260B2 (en) * | 2018-11-27 | 2022-10-21 | 株式会社京三製作所 | Track circuit monitoring device |
-
1988
- 1988-09-07 JP JP63224028A patent/JPH0619406B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0271168A (en) | 1990-03-09 |
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