JPH0428065Y2 - - Google Patents
Info
- Publication number
- JPH0428065Y2 JPH0428065Y2 JP1982076977U JP7697782U JPH0428065Y2 JP H0428065 Y2 JPH0428065 Y2 JP H0428065Y2 JP 1982076977 U JP1982076977 U JP 1982076977U JP 7697782 U JP7697782 U JP 7697782U JP H0428065 Y2 JPH0428065 Y2 JP H0428065Y2
- Authority
- JP
- Japan
- Prior art keywords
- current
- transformer
- ground
- wire
- phase
- 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
Links
- 239000003990 capacitor Substances 0.000 claims description 15
- 238000001514 detection method Methods 0.000 claims description 5
- 238000010586 diagram Methods 0.000 description 11
- 238000000034 method Methods 0.000 description 8
- 238000009413 insulation Methods 0.000 description 6
- 230000007935 neutral effect Effects 0.000 description 5
- 239000002131 composite material Substances 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 238000013459 approach Methods 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- WABPQHHGFIMREM-UHFFFAOYSA-N lead(0) Chemical compound [Pb] WABPQHHGFIMREM-UHFFFAOYSA-N 0.000 description 1
- 238000000691 measurement method Methods 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
Landscapes
- Measurement Of Resistance Or Impedance (AREA)
Description
【考案の詳細な説明】
低圧電路の絶縁抵抗は、電気設備技術基準によ
つて定められた値に常に保持されなければならな
いとともに、電気工作物施設の責任者は、定期的
にその抵抗値を測定し記録しておかなければなら
ない。[Detailed description of the invention] The insulation resistance of low-voltage electrical circuits must always be maintained at the value specified by the electrical equipment technical standards, and the person in charge of electrical facility facilities must regularly check the resistance value. Must be measured and recorded.
近年この絶縁抵抗値を自動的に測定する方法が
考案されているが、その一つの方法として、第１
図示のように高圧より低圧に変成する変圧器１の
中性点または一端子に施す接地線２に変流器３を
取り付け、変圧器１の低圧側より引き出す電路の
電圧側よりの地絡電流は必ず接地線へ還流するこ
とを利用し、変流器３に接続した検出器３′に検
出される二次出力の大きさによつて低圧電路の絶
縁の劣化度を判定しようとするものである。 In recent years, methods have been devised to automatically measure this insulation resistance value, and one method is the first one.
As shown in the figure, a current transformer 3 is attached to the grounding wire 2 connected to the neutral point or one terminal of the transformer 1, which transforms from high voltage to low voltage, and the ground fault current from the voltage side of the electrical line drawn from the low voltage side of the transformer 1. This method utilizes the fact that the current always returns to the ground wire, and attempts to judge the degree of deterioration of the insulation of the low-voltage circuit based on the magnitude of the secondary output detected by the detector 3' connected to the current transformer 3. be.
しかしながら、この方法には、次のような問題
点がある。 However, this method has the following problems.
すなわち、１組の変圧器１の低圧側の電路４の
総亘長が非常に長い場合、さらに電線管、ダクト
などに長く入つている場合などにおいては、相当
な大きさの対地静電容量があるため、単相２戦式
電路の一端接地の場合、あるいは三相３線式電路
の一端接地の場合には、対地静電容量のベクトル
和が０とならず、充電々流が変圧器１の接地線２
に流れている。また電路４につながる負荷機器５
もそれぞれ接地した金属製外箱などを通して対地
静電容量をもつている。 In other words, if the total length of the low-voltage side electrical circuit 4 of a pair of transformers 1 is very long, or if it is inserted into a conduit or duct for a long time, a considerable amount of ground capacitance will be generated. Therefore, when one end of a single-phase, two-wire system is grounded, or when one end of a three-phase, three-wire system is grounded, the vector sum of the ground capacitances does not become 0, and the charging current flows through the transformer 1. Ground wire 2
It is flowing to. Also, the load equipment 5 connected to the electric line 4
Each has a ground capacitance through a grounded metal outer box.
さらに、中性点接地式電路においても、電圧側
の一線に地絡が生ずると、各線の対地静電容量の
バランスがくづれ、充電々流が流れることにな
る。 Furthermore, even in a neutral point grounding type electrical circuit, if a ground fault occurs in one wire on the voltage side, the balance of the ground capacitance of each wire will be disrupted, and a current of charge will flow.
電路４が、がいし引き配線や架空線路であつ
て、対地静電容量が微小のときは問題にならない
が、対地静電容量によるインピーダンスが、電路
４の対地間漏洩抵抗の値に近くなつてくると、前
記変流器３による漏れ電流測定法は充電々流分が
多くなり、正しい絶縁抵抗を判定することができ
なくなる。 If the electric line 4 is an insulated wiring or an overhead line and the ground capacitance is small, this will not be a problem, but as the impedance due to the ground capacitance becomes close to the value of the earth leakage resistance of the electric line 4. In this case, the leakage current measurement method using the current transformer 3 has a large charging current, making it impossible to determine the correct insulation resistance.
この静電容量分を除去する方策の一例として、
特開昭50−2142号公報に記載されているような漏
れ電流の測定方法があるが、この方法では、変流
器又は零相変流器により検出された漏れ電流と、
電流位相整定器で作られた基準相電流を同相電流
除去器に同時に与えるように構成するため、製品
化において構造が複雑化し、価格が割高になると
いう欠点があり、その他の方策でも、同様の欠点
があつた。 As an example of a measure to remove this capacitance,
There is a method for measuring leakage current as described in JP-A No. 50-2142, but in this method, the leakage current detected by a current transformer or zero-phase current transformer,
Since the reference phase current created by the current phase setter is configured to be simultaneously applied to the common-mode current eliminator, the structure becomes complicated and the price becomes relatively high. There were flaws.
本考案は、低圧電路に接続した変圧器の第二種
接地線を貫通させた変流器に他の電線を貫通さ
せ、この電線に接続した可変容量コンデンサで静
電容量分を除去するように構成することにより、
上記従来例に比し、構造が単純で、価格を安価に
しうる対地静電容量補償装置を提供しようとする
ものである。 In this invention, the type 2 grounding wire of the transformer connected to the low-voltage line is passed through the current transformer, and another wire is passed through it, and the capacitance is removed by a variable capacitor connected to this wire. By configuring
It is an object of the present invention to provide a ground capacitance compensator that has a simpler structure and can be lower in price than the conventional example described above.
以下図面第２図ないし第８図にもとずいて本考
案の実施例を説明すると、変圧器６の二次側に接
続した低圧電路７の対地静電容量をCg、対地絶
縁抵抗をRg、これらCg，Rgを通つて対地へ流れ
る電流をそれぞれi〓C，i〓Rとし、変圧器６の第２種
接地線８に戻る電流をi〓Zとすれば、i〓Z＝i〓C−i〓R
それ
ぞれの正方向を第２図のようにとり、ベクトルで
表わすと第３図のようになる。 An embodiment of the present invention will be described below based on FIGS. 2 to 8 of the drawings. The ground capacitance of the low voltage line 7 connected to the secondary side of the transformer 6 is Cg, the ground insulation resistance is Rg, If the currents flowing to the ground through these Cg and Rg are respectively i〓 C and i〓 R , and the current returning to the second type grounding wire 8 of the transformer 6 is i〓 Z , then i〓 Z = i〓 C −i〓 R
If each positive direction is taken as shown in Figure 2 and expressed as a vector, it will be as shown in Figure 3.
ここで、iCの大きさがわかれば、i〓Zは第二種接
地線８を貫通させた変流器９の二次出力であるか
ら、i〓Z−i〓Cを計算すればiR分を求められるが、通
常では、iCは分布電流であり、その大きさはわか
らない。 Here, if the magnitude of i C is known, i〓 Z is the secondary output of the current transformer 9 that passes through the second type grounding wire 8, so if i〓 Z −i〓 C is calculated, i R Normally, i C is a distributed current, and its magnitude is unknown.
本考案は、このiC分を補償する、すなわち打ち
消すことを考え、第２図示のような変流器９へ他
の電線１０を貫通させ、この電線１０の一端１１
は変圧器６の二次側の一端子に接続し、他端１２
は補償用コンデンサ１３の一端に接続し、補償用
コンデンサ１３の他端と変圧器６の二次側の残り
の一端子を別の電線１４で接続し、補償用コンデ
ンサ１３の可変静電容量C′を通って流れる電流
iC′が変流器９の二次側においてiZ（含まれるiC）
による二次側電流と逆方向に流れるようにする。 In the present invention, in consideration of compensating for, or canceling out, this i C component, another electric wire 10 is passed through the current transformer 9 as shown in the second figure, and one end 11 of this electric wire 10 is
is connected to one terminal on the secondary side of the transformer 6, and the other end 12
is connected to one end of the compensation capacitor 13, and the other end of the compensation capacitor 13 and the remaining terminal on the secondary side of the transformer 6 are connected with another electric wire 14, and the variable capacitance C of the compensation capacitor 13 is current flowing through ′
i C ′ is i Z (included i C ) on the secondary side of current transformer 9
so that the secondary current flows in the opposite direction.
上記の回路において、補償用コンデンサ１３の
可変静電容量C′を加減すると、iC′はiCとちようど
逆方向になるため、第５図のベクトル図に示すよ
うにiZも変化する。このiZを変流器９の出力端子
に接続したベクトル和検出用電流測定器１５で読
みながら最小値になるように可変静電容量C′を加
減すればiR分のみとすることができる。 In the above circuit, when the variable capacitance C' of the compensation capacitor 13 is adjusted, i C ' becomes exactly opposite to i C , so i Z also changes as shown in the vector diagram in Figure 5. do. By reading this i Z with a vector sum detection current measuring device 15 connected to the output terminal of the current transformer 9 and adjusting the variable capacitance C' so that it becomes the minimum value, only i R can be obtained. .
なお、上記回路における補償用コンデンサ１３
には、例えば第４図示のように入力端子１６、可
変容量コンデンサ群１７と、容量可変用タツプ１
８と、切換器１９とを備え、容量を大幅に可変で
きるコンデンサを使用し、またベクトル和検出用
電流測定器１５には、例えば第４図示のように入
力端子２０と、増巾器２１と、増巾器用電源２２
と、電流計２３とを備えたものを使用する。これ
ら補償用コンデンサ１３、ベクトル和検出用電流
測定器１５は、必要に応じて片方のみでも使用で
きるように分けて構成することもある。 Note that the compensation capacitor 13 in the above circuit
For example, as shown in FIG.
8 and a switch 19, and a capacitor whose capacitance can be greatly varied is used.The vector sum detection current measuring device 15 has an input terminal 20, an amplifier 21, and an amplifier 21, for example, as shown in the fourth figure. , amplifier power supply 22
and an ammeter 23 are used. The compensation capacitor 13 and the vector sum detection current measuring device 15 may be configured separately so that only one of them can be used, if necessary.
第５図の位相角φが０に近くなれば、iZの変化
はほとんどなくなるので、C′の値が多少変化して
も実用的には差支えない。 When the phase angle φ in FIG. 5 approaches 0, there is almost no change in i Z , so there is no practical problem even if the value of C' changes somewhat.
ただし、例えば対地間100Vとし、絶縁抵抗
0.1MΩとすれば、対地漏洩電流は1mAであり、
これを検出する変流器ならびに電流測定器は特に
高感度、高性能のものが必要である。 However, for example, if the voltage is 100V to ground, the insulation resistance
If it is 0.1MΩ, the earth leakage current is 1mA,
The current transformer and current measuring device that detect this need to be particularly sensitive and high performance.
三相３線式の一端接地式の場合は、例えば第６
図のようにＢ相が接地してあると、Ａ相、Ｃ相の
対地間静電容量は、線間電圧に対する進み電流と
なり、第６図ｂのようなベクトル図となる。なお
簡単のため、Ａ，Ｃ相とも常時漏れ抵抗による電
流は省いてある。 In the case of a three-phase three-wire one-end grounded type, for example, the sixth
When the B phase is grounded as shown in the figure, the ground capacitance of the A and C phases becomes a leading current with respect to the line voltage, resulting in a vector diagram as shown in FIG. 6b. For simplicity, the current due to constant leakage resistance in both A and C phases is omitted.
いま、第７図のようにＣ相に地絡事故があり大
地漏れ電流が流れると、対地間充電々流iCは２相
分であるから、第二種接地線８に流れるiZは第６
図ｂのようにiR2より小さくなり、前述の単相の
方法は適用できなくなる。 Now, as shown in Figure 7, if there is a ground fault in the C phase and a ground leakage current flows, the ground-to-ground charging current i 6
As shown in Figure b, i becomes smaller than R2 , and the single-phase method described above cannot be applied.
また三相の場合は、位相関係が複雑であり、
iC1とiC2の合成iCを打ち消すべきiC′は（VCAに対
する進み電流で）作れるが、特別な条件の場合を
のぞき、ベクトル的にもiCを分離するのは無理で
ある。 In addition, in the case of three-phase, the phase relationship is complicated,
Although i C ′ , which should cancel the composite i C of i C1 and i C2 , can be created (using the lead current for VCA), it is impossible to separate i C vectorwise, except under special conditions.
このことは、第８図のように、中性点接地方式
の電路の場合などで、各線路の対地静電容量が等
しい場合（合計iCは０となる）、異なる場合（ど
の相の電流かわからない）なども同様のことが言
え、合成iZから補償分を見出すのは無理である。 As shown in Figure 8, in the case of a neutral point grounded type electric line, this is true when the ground capacitance of each line is equal (the total i C is 0), and when it is different (which phase's current The same thing can be said for cases such as "I don't know", and it is impossible to find the compensation amount from the composite i Z.
また電路の対地静電容量によるiCは、地絡事故
抵抗の大きさによつて多少は変化するが、漏れ電
流を測定する場合程度であればまず一定とみてよ
い。 In addition, i C due to the ground capacitance of the electrical circuit changes somewhat depending on the magnitude of the ground fault fault resistance, but it can be considered to be constant when measuring leakage current.
以上から一端接地の三相電路、ならびに中性点
接地電路では、測定すべき電路を第７図示のよう
にスイツチ２４で一旦開放し、１相づつ電源側と
負荷側をわたり用リード線２５で結び、単相回路
として測定するようにする。すなわち補償用コン
デンサ１３に切換スイツチ２６をもうけ、わたり
線２５でＡ相のみを充電した場合は切換スイツチ
をの側に倒し測定、Ｃ相のみを充電した場合は
切換スイツチをの側に倒し別々に測定する。 From the above, in the case of a three-phase circuit with one end grounded and a neutral point grounded circuit, the circuit to be measured is first opened with the switch 24 as shown in Figure 7, and the lead wire 25 is used to cross the power supply side and the load side one phase at a time. and measure it as a single-phase circuit. In other words, a changeover switch 26 is provided in the compensation capacitor 13, and when only the A phase is charged with the crossover wire 25, the changeover switch is turned to the side for measurement, and when only the C phase is charged, the changeover switch is turned to the side and measured separately. Measure.
この値を負荷の停電可能の時測定記録してお
き、それ以後の常時測定時は、測定器の静電容量
のレンジ及び目盛付きダイヤルで前もつて設定し
ておくようにすれば、停電しないで測定できる。
ただしこの場合は補償用コンデンサは２個必要で
ある。 If you measure and record this value when a load power outage is possible, and then set it in advance using the capacitance range and scaled dial of the measuring instrument during regular measurements thereafter, you can avoid power outages. It can be measured by
However, in this case, two compensation capacitors are required.
本考案は、叙上のように構成したから、製品化
において、従来の静電容量分を除去する装置に比
し、構造が単純で、価格が安価な対地静電容量補
償装置を提供することができる。 Since the present invention is configured as described above, it is possible to provide a ground capacitance compensating device that has a simpler structure and is cheaper in commercialization than conventional devices that remove capacitance. I can do it.
第１図は変圧器の二次側一端子の第二種接地及
びこの接地線を流れる電流より対地漏洩電流を検
出する方法の説明図、第２図は単相電路において
補償用コンデンサを使用して対地静電容量による
地絡電流分を変流器の二次出力側において打ち消
す回路図、第３図は対地漏れ抵抗と、対地漏れ静
電容量による合成電流のベクトル図、第４図は第
２図の検出器の構成を概略的に示す図、第５図は
補償用コンデンサを使用した場合の電流地の変化
の説明図、第６図ａは三相一端接地の電圧関係ベ
クトル図、第６図ｂは三相一端接地の電圧相の一
相に地絡が発生した場合のベクトル図、第７図は
三相一端接地の場合に１相ごとに測定する場合の
回路図、第８図は中性点接地方式の電路において
各線の対地静電容量が平衡している場合は静電容
量による地絡電流の総和が０になる説明図であ
る。
８……第２種接地線、９……変流器、１０……
他の電線、１３……補償用コンデンサ、１４……
別の電線、１５……ベクトル和検出用電流測定
器。
Figure 1 is an explanatory diagram of the type 2 grounding of one terminal on the secondary side of a transformer and a method for detecting earth leakage current from the current flowing through this grounding wire. Figure 3 is a vector diagram of the combined current due to earth leakage resistance and earth leakage capacitance, and Figure 4 is a circuit diagram for canceling the earth fault current due to earth capacitance on the secondary output side of the current transformer. Figure 2 is a diagram schematically showing the configuration of the detector, Figure 5 is an explanatory diagram of changes in current ground when a compensation capacitor is used, Figure 6a is a voltage relationship vector diagram of three phases with one end grounded, Figure 6b is a vector diagram when a ground fault occurs in one voltage phase of a three-phase one-end grounding system, Figure 7 is a circuit diagram when measuring each phase in a three-phase one-end earthing system, and Figure 8 is an explanatory diagram in which the sum of ground fault currents due to capacitance becomes 0 when the ground capacitance of each wire is balanced in a neutral point grounding type electrical circuit. 8...Class 2 grounding wire, 9...Current transformer, 10...
Other wires, 13... Compensation capacitor, 14...
Another electric wire, 15... current measuring device for vector sum detection.
Claims (1)
貫通させて電路の漏れ電流を測定する変流器に
他の電線を貫通させ、この電線の一端は上記変
圧器の二次側の一端子に接続し、他端は可変容
量コンデンサの一端に接続し、この可変容量コ
ンデンサの他端と上記変圧器の二次側の残りの
一端子を別の電線で接続し、上記変流器の出力
端子にベクトル和検出用電流測定器を接続して
成る低圧電路対地静電容量補償装置。 (2) 可変容量コンデンサボツクスとベクトル和検
出用電流測定器とを区分し、必要に応じ片方の
みでも使用可能にした実用新案登録請求の範囲
第１項記載の低圧電路対地静電容量補償装置。[Scope of Claim for Utility Model Registration] (1) A second-class grounding wire of a transformer connected to a low-voltage electric line is passed through the current transformer to measure the leakage current of the electric line, and another electric wire is passed through the current transformer, and one end of this electric wire is passed through. is connected to one terminal on the secondary side of the transformer, the other end is connected to one end of the variable capacitor, and the other end of the variable capacitor and the remaining terminal on the secondary side of the transformer are connected to another terminal. A low-voltage line-to-ground capacitance compensator comprising a current measuring device for detecting a vector sum connected to the output terminal of the current transformer by an electric wire. (2) The low-voltage line-to-ground capacitance compensator according to claim 1, which separates the variable capacitor box and the current measuring device for vector sum detection so that only one can be used as needed.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7697782U JPS58180478U (en) | 1982-05-27 | 1982-05-27 | Low-voltage line-to-ground capacitance compensator |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7697782U JPS58180478U (en) | 1982-05-27 | 1982-05-27 | Low-voltage line-to-ground capacitance compensator |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS58180478U JPS58180478U (en) | 1983-12-02 |
| JPH0428065Y2 true JPH0428065Y2 (en) | 1992-07-07 |
Family
ID=30086257
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP7697782U Granted JPS58180478U (en) | 1982-05-27 | 1982-05-27 | Low-voltage line-to-ground capacitance compensator |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS58180478U (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2006226879A (en) * | 2005-02-18 | 2006-08-31 | Chugoku Electric Power Co Inc:The | Leakage current measuring instrument |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS502142A (en) * | 1973-05-15 | 1975-01-10 |
-
1982
- 1982-05-27 JP JP7697782U patent/JPS58180478U/en active Granted
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS502142A (en) * | 1973-05-15 | 1975-01-10 |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS58180478U (en) | 1983-12-02 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US5933012A (en) | Device for sensing of electric discharges in a test object | |
| CN111095000A (en) | High fidelity voltage measurement using capacitively coupled voltage transformers | |
| JPH0428065Y2 (en) | ||
| Nikander et al. | Methods for earth fault identification and distance estimation in a compensated medium voltage distribution network | |
| JP3586266B2 (en) | Fault location method for transmission line and fault location system using the same | |
| US7142403B2 (en) | Method for detection of a ground fault, which occurs in the vicinity of a neutral point in an electrical device, as well as an apparatus for carrying out the method | |
| CN212111734U (en) | Grounding fault phase detection system of ITN power supply system | |
| Lian et al. | An overview of the digital fault location algorithms for the power transmission line protection based on the steady-state phasor approaches | |
| Moore et al. | Measurement of short circuit load losses in large three phase power transformers using an alternating current comparator bridge | |
| JP3206945B2 (en) | Ground fault detection method and apparatus for electric circuit | |
| LV13922B (en) | Method for determination of distance to fault place by phase-to-earth fault in distribution networks | |
| JPH04220573A (en) | Low-voltage system line wire insulation monitoring method | |
| KR102220329B1 (en) | Apparatus for measuring leakage current in low voltage electric power lines and method thereof | |
| Rahmatian | Design and application of optical voltage and current sensors for relaying | |
| JP3341651B2 (en) | Three-wire circuit voltage detector | |
| JPH0425659Y2 (en) | ||
| SU1224750A1 (en) | Apparatus for determining range to single-phase earth in electrical mains with grounded neutral | |
| Paramzin et al. | Selecting the Alternating Current Waveform Measurement Channel for Detecting a Feeder With a Single-Phase Ground Fault | |
| Castelli | The potential transformer bridge with current comparator for measuring the voltage dependence of compressed-gas capacitors | |
| JP2750713B2 (en) | Simple insulation resistance measurement method for low voltage wiring etc. | |
| JPH028529B2 (en) | ||
| Brazier | Dielectric loss-angle measurement of multi-core high-tension cables, with special reference to the schering bridge | |
| Roberts et al. | New Directional Ground-Fault Elements Improve Sensitivity in Ungrounded and Compensated Networks | |
| Arri et al. | Status assessment of transformer windings via on-line stray inductance measurement | |
| SU1594445A1 (en) | Method of determining active and reactive components of insulation resistance of three-phase four-wire mains with grounded neutral |