JP2010062419A

JP2010062419A - Zero-phase current transformer

Info

Publication number: JP2010062419A
Application number: JP2008228037A
Authority: JP
Inventors: Sadaji Okane; 貞治大金
Original assignee: Tokyo Electric Power Co Inc
Current assignee: Tokyo Electric Power Company Holdings Inc
Priority date: 2008-09-05
Filing date: 2008-09-05
Publication date: 2010-03-18

Abstract

<P>PROBLEM TO BE SOLVED: To provide a zero-phase current transformer easily installable on an existing power distribution line, and capable of minimizing a residual current. <P>SOLUTION: An iron core 11 is formed annularly by jointing a plurality of circular-arc-like iron core members 13 to one another, a plurality of divided secondary coils 12 are mounted by moving arrangement positions to the iron core 11, and the divided secondary coils 12 are serially connected to one another to output currents generated in the divided secondary coils 12 from output terminals 19. The divided secondary coils 12 are moved along the iron core 11 to identify positions of the divided secondary coils 12 for minimizing residual currents generated in the secondary coils 12, and the divided secondary coils 12 are arranged at the identified positions. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

本発明は、零相電流を検出する零相変流器に関する。 The present invention relates to a zero-phase current transformer that detects a zero-phase current.

例えば、三相の６ｋＶ配電線の地絡電流は三相の零相変流器（ＺＣＴ）で検出される。すなわち、零相変流器は、配電線に地絡事故が発生した場合に発生する零相電流を検出し地絡方向継電器に入力する。地絡方向継電器は、零相変流器で検出された零相電流に基づいて配電線の地絡事故判定を行う。 For example, the ground fault current of a three-phase 6 kV distribution line is detected by a three-phase zero-phase current transformer (ZCT). That is, the zero-phase current transformer detects a zero-phase current that is generated when a ground fault occurs in the distribution line, and inputs it to the ground fault direction relay. The ground fault direction relay determines a ground fault in the distribution line based on the zero phase current detected by the zero phase current transformer.

図６は配電用変電所における配電系統の一例を示す系統図である。配電用変圧器２１は、一次側の送電線の電圧を降圧して２次側の配電線に電力を供給するものであり、通常、２次側の母線２２には複数の配電線が接続されている。図６では３系統の配電線２３ａ〜２３ｃが接続された場合を示している。各々の配電線２３ａ〜２３ｃは遮断器２４ａ〜２４ｃを介して負荷に電力を供給する。各々の配電線２３ａ〜２３ｃには零相変流器２５ａ〜２５ｃが配置され、零相変流器２５ａ〜２５ｃで検出された零相電流は、それぞれ地絡方向継電器２６ａ〜２６ｃに入力される。地絡方向継電器２６ａ〜２６ｃは零相変流器２５ａ〜２５ｃで検出された零相電流に基づいて配電線２３ａ〜２３ｃの地絡事故判定を行い、地絡事故と判定した場合には、地絡事故と判定した配電線２３ａ〜２３ｃの遮断器２４ａ〜２４ｃを開放する。 FIG. 6 is a system diagram showing an example of a distribution system in a distribution substation. The distribution transformer 21 steps down the voltage of the primary transmission line and supplies power to the secondary distribution line. Usually, a plurality of distribution lines are connected to the secondary bus 22. ing. FIG. 6 shows a case where three distribution lines 23a to 23c are connected. Each distribution line 23a-23c supplies electric power to a load via the circuit breakers 24a-24c. Zero-phase current transformers 25a to 25c are arranged in the respective distribution lines 23a to 23c, and zero-phase currents detected by the zero-phase current transformers 25a to 25c are respectively input to the ground fault direction relays 26a to 26c. . The ground fault direction relays 26a to 26c determine the ground fault of the distribution lines 23a to 23c based on the zero phase current detected by the zero phase current transformers 25a to 25c. The circuit breakers 24a to 24c of the distribution lines 23a to 23c that have been determined to have a tie-up accident are opened.

三相の零相変流器は、環状鉄心に２次側コイルを巻回し、１次側は環状鉄心で囲まれた空間に３相の導体を貫通して構成される。そして、１次側の３相の導体を流れる電流のベクトル和に対応した２次電流を零相電流として２次側コイルから取り出す。 A three-phase zero-phase current transformer is configured by winding a secondary coil around an annular iron core and penetrating a three-phase conductor in a space surrounded by the annular iron core on the primary side. Then, the secondary current corresponding to the vector sum of the currents flowing through the primary-side three-phase conductor is taken out from the secondary-side coil as a zero-phase current.

このような零相変流器では、鉄心材料の透磁率、１次側導体の位置及び２次側コイルの巻き方や配置、鉄心の磁気飽和などの影響で、地絡電流（漏れ電流）がない場合であっても２次側コイルに残留電流が出力されることがある。残留電流は負荷電流に比例して変化する特性を有し、配電線には多くの高調波成分を含んだ電流が流れているため残留電流にも高調波成分が含まれる。また、残留電流は、鉄心を傾けたり、鉄心と導体との距離の変化により変化する。これは、鉄心と１次側導体との位置関係を変化させることにより磁路が変化し、その磁路の変化により残留電流が変化するためである。 In such a zero-phase current transformer, the ground fault current (leakage current) is influenced by the magnetic permeability of the iron core material, the position of the primary side conductor and the winding and arrangement of the secondary side coil, the magnetic saturation of the iron core, etc. Even if it is not, a residual current may be output to the secondary coil. The residual current has a characteristic that changes in proportion to the load current, and since a current containing many harmonic components flows through the distribution line, the residual current also contains harmonic components. Further, the residual current changes depending on the tilt of the iron core or the change in the distance between the iron core and the conductor. This is because the magnetic path is changed by changing the positional relationship between the iron core and the primary conductor, and the residual current is changed by the change of the magnetic path.

零相変流器で検出された信号は、前述したように、地絡方向継電器に入力されて地絡事故の判定に使用されるので、零相変流器から残留電流が出力された場合には地絡方向継電器が誤動作する虞がある。地絡方向継電器は高感度に設定されているので、小さい残留電流であっても地絡方向継電器が誤動作する虞がある。誤動作防止のためには地絡方向継電器の感度を鈍くすることになるが、そうすると、微地絡事故を検出することができなくなる。 As described above, the signal detected by the zero-phase current transformer is input to the ground fault relay and used to determine the ground fault, so when the residual current is output from the zero-phase current transformer May cause the ground fault direction relay to malfunction. Since the ground fault direction relay is set with high sensitivity, the ground fault direction relay may malfunction even with a small residual current. In order to prevent malfunction, the sensitivity of the ground fault direction relay is made dull, but in this case, it becomes impossible to detect a micro ground fault.

そこで、鉄心にパーマロイ等の高磁性体を使用し、負荷電流の流れる導体の間隔を所定寸法に保持して２次側コイルを分布巻きしたりして、残留電流が発生しないように零相変流器を製作している。 Therefore, a high-magnetic material such as permalloy is used for the iron core, and the secondary coil is distributedly wound while maintaining the distance between the conductors through which the load current flows at a predetermined size, so that the zero phase change is prevented. I'm making a fluency.

また、貫通形の零相変流器は鉄心が環状となっており、環状鉄心に導体を貫通させなければならないので、既設の配電線路に後から設置することが困難である。そこで、鉄心を分割して構成し、既設の導体を挟むように分割鉄心を接合するようにした分割形の零相変流器がある。このような分割形の零相変流器としては、２次側コイルを、巻き数及び長さを同じくした６個のコイルに分割し、その２個を半円状の各鉄心の中央に、他の４個を分割した鉄心の両端で噛合部にかからない位置に近設し、製作に熟練を要せず工数が低減され、しかも残留電流も少なくしたものがある（例えば、特許文献１参照）。
特開平１−２１４００３号公報 In addition, the through-type zero-phase current transformer has an annular iron core, and a conductor must be penetrated through the annular iron core, so that it is difficult to install it later in an existing distribution line. Therefore, there is a split-type zero-phase current transformer that is configured by dividing the iron core and joining the split iron core so as to sandwich an existing conductor. As such a split-type zero-phase current transformer, the secondary coil is divided into six coils having the same number of turns and the same length, and two of them are arranged at the center of each semicircular iron core, There are those in which the other four cores are located close to the positions that do not reach the meshing portion, the skill is not required for production, the man-hours are reduced, and the residual current is also reduced (for example, see Patent Document 1) .
JP-A-1-214003

しかし、特許文献１のものでは、分割した６個のコイルの配置位置は、予め決められた位置であるので、必ずしも残留電流が最小になるとは限らない。残留電流は、前述したように、鉄心材料の透磁率、１次側導体の位置及び２次側コイルの巻き方や配置、鉄心の磁気飽和などの影響を受けるので、分割したコイルを予め決められた位置に配置しただけでは残留電流は最小にならない。 However, in the thing of patent document 1, since the arrangement | positioning position of six divided coils is a predetermined position, a residual current is not necessarily the minimum. As described above, the residual current is affected by the magnetic permeability of the iron core material, the position of the primary side conductor, the winding and arrangement of the secondary side coil, the magnetic saturation of the iron core, etc. Residual current is not minimized just by placing it at a different position.

本発明の目的は、既設の配電線路に容易に設置することができ、しかも残留電流を最も小さくできる零相変流器を提供することである。 An object of the present invention is to provide a zero-phase current transformer that can be easily installed in an existing distribution line and that can minimize the residual current.

本発明の零相変流器は、複数個の円弧状の鉄心部材を接合させて環状に形成された鉄心と、前記鉄心への配置位置が移動可能に装着される複数個の分割２次側コイルと、前記分割２次側コイルを直列接続して前記分割２次側コイルに発生した電流を出力する出力端子とを備え、前記分割２次側コイルを前記鉄心に沿って移動させ、前記２次側コイルに発生する残留電流が最も小さくなる前記分割２次側コイルの位置を特定し、その特定された位置に前記分割２次側コイルを配置することを特徴とする。 The zero-phase current transformer of the present invention includes a core formed in an annular shape by joining a plurality of arc-shaped core members, and a plurality of divided secondary sides on which the arrangement position on the core is movably mounted. A coil and an output terminal for outputting the current generated in the divided secondary coil by connecting the divided secondary coil in series, and moving the divided secondary coil along the iron core; The position of the divided secondary coil that minimizes the residual current generated in the secondary coil is specified, and the divided secondary coil is arranged at the specified position.

本発明によれば、複数個の円弧状の鉄心部材を接合させて環状に鉄心を形成しているので、既設の配電線路に容易に設置することができる。また、鉄心に装着する２次側コイルは、複数個に分割して移動可能に鉄心に配置され、分割された分割２次側コイルを鉄心に沿って移動させて２次側コイルに発生する残留電流が最も小さくなる位置を特定し、その特定された位置に分割２次側コイルを配置するので、残留電流が小さい零相変流器を提供できる。従って、零相変流器の出力を入力として動作する地絡方向継電器の誤動作を防止でき、微地絡事故も高感度に検出できる。 According to the present invention, since a plurality of arc-shaped iron core members are joined to form an annular iron core, it can be easily installed on an existing distribution line. Further, the secondary coil to be mounted on the iron core is divided into a plurality of pieces and arranged on the iron core so as to be movable, and the divided secondary coil is moved along the iron core to generate a residual in the secondary coil. Since the position where the current becomes the smallest is specified and the divided secondary coil is arranged at the specified position, a zero-phase current transformer with a small residual current can be provided. Therefore, it is possible to prevent malfunction of the ground fault direction relay that operates using the output of the zero phase current transformer as an input, and it is possible to detect a micro ground fault with high sensitivity.

図１は本発明の実施の形態に係わる零相変流器の構成図である。図１に示すように、零相変流器は、鉄心１１に複数個の分割２次側コイル１２ａ〜１２ｄが装着されて構成される。図１では４個の分割２次側コイル１２ａ〜１２ｄが装着された場合を示している。鉄心１１は、複数個の鉄心部材１３ａ、１３ｂと、複数個の鉄心部材１３ａ、１３ｂを環状に固定する固定具１４とから構成される。図１では２個の鉄心部材１３ａ、１３ｂである場合を示している。固定具１４は、分割された２個の鉄心部材１３ａ、１３ｂの外周面の１周を巻回して配置され、固定具１４の端部には留め部１５ａ、１５ｂが形成されている。そして、留め部１５ａ、１５ｂの間をボルト１６及びナット１７で固定することにより、固定具１４で分割された２個の鉄心部材１３ａ、１３ｂを固定し鉄心１１を形成する。 FIG. 1 is a configuration diagram of a zero-phase current transformer according to an embodiment of the present invention. As shown in FIG. 1, the zero-phase current transformer is configured by mounting a plurality of divided secondary coils 12 a to 12 d on an iron core 11. FIG. 1 shows a case where four divided secondary coils 12a to 12d are mounted. The iron core 11 includes a plurality of iron core members 13a and 13b and a fixture 14 that fixes the plurality of iron core members 13a and 13b in a ring shape. In FIG. 1, the case where it is the two iron core members 13a and 13b is shown. The fixture 14 is arranged by winding one circumference of the outer peripheral surfaces of the two divided iron core members 13 a and 13 b, and fastening portions 15 a and 15 b are formed at the ends of the fixture 14. And by fixing between the fastening parts 15a and 15b with the volt | bolt 16 and the nut 17, the two iron core members 13a and 13b divided | segmented with the fixing tool 14 are fixed, and the iron core 11 is formed.

このように形成された鉄心１１には、鉄心１１への配置位置が移動可能に装着される４個の分割２次側コイル１２ａ〜１２ｄが装着されている。４個の分割２次側コイル１２ａ〜１２ｄは配線１８にて直列接続され、分割２次側コイル１２ａ〜１２ｄに発生した電流を出力する出力端子１９から外部に出力される。 On the iron core 11 formed in this way, four divided secondary coils 12a to 12d to which the arrangement position on the iron core 11 is movably mounted are mounted. The four divided secondary coils 12a to 12d are connected in series by the wiring 18, and are output to the outside from an output terminal 19 that outputs a current generated in the divided secondary coils 12a to 12d.

図２は本発明の実施の形態に係わる零相変流器の鉄心部材の斜視図である。複数個の鉄心部材は環状の鉄心部材を複数個に分割して形成される。図２では、２個の鉄心部材１３ａ、１２ｂに分割された場合を示しており、これら２個の鉄心部材１３ａ、１３ｂは環状の鉄心部材を２分割して形成されることから、各々の鉄心部材１３ａ、１３ｂは円弧状に形成されることになる。そして、分割された部分を接合させて環状の鉄心部材とする。 FIG. 2 is a perspective view of the iron core member of the zero-phase current transformer according to the embodiment of the present invention. The plurality of iron core members are formed by dividing an annular iron core member into a plurality of pieces. FIG. 2 shows a case where the core member is divided into two iron core members 13a and 12b. Since these two iron core members 13a and 13b are formed by dividing an annular iron core member into two, each iron core is formed. The members 13a and 13b are formed in an arc shape. And the divided | segmented part is joined and it is set as a cyclic | annular iron core member.

図３は本発明の実施の形態に係わる零相変流器の鉄心の斜視図である。図３に示すように、分割された２個の鉄心部材１３ａ、１３ｂを接合して環状の鉄心部材とし、その環状の鉄心部材を固定具１４で結合することにより環状の鉄心１１を形成する。固定具１４は、分割された２個の鉄心部材１３ａ、１３ｂの外周面の１周を巻回して配置され、留め部１５ａ、１５ｂでボルト１６及びナット１７で固定される。 FIG. 3 is a perspective view of the iron core of the zero-phase current transformer according to the embodiment of the present invention. As shown in FIG. 3, the two divided core members 13 a and 13 b are joined to form an annular core member, and the annular core member is joined by a fixture 14 to form the annular core 11. The fixture 14 is arranged by winding one circumference of the outer peripheral surfaces of the two divided iron core members 13a and 13b, and is fixed by bolts 16 and nuts 17 by fastening portions 15a and 15b.

次に、鉄心１１への分割２次側コイル１２の装着の仕方について説明する。図４は本発明の実施の形態に係わる零相変流器の鉄心の形成過程の斜視図、図５は分割２次コイル１２の斜視図である。 Next, how to install the divided secondary coil 12 on the iron core 11 will be described. FIG. 4 is a perspective view of the process of forming the iron core of the zero-phase current transformer according to the embodiment of the present invention, and FIG. 5 is a perspective view of the divided secondary coil 12.

図４に示すように、１個の鉄心部材１３ａの外周面に固定具１４を接触させた状態の鉄心１１の形成過程において、固定具１４の留め部１５ａ、１５ｂ部分の開口部から図５に示す分割２次側コイル１２を挿入する。 As shown in FIG. 4, in the process of forming the iron core 11 with the fixture 14 in contact with the outer peripheral surface of one iron core member 13a, the openings of the fastening portions 15a and 15b of the fixture 14 are shown in FIG. The split secondary coil 12 shown is inserted.

分割２次側コイル１２は、図５に示すように四角筒状に形成され、筒体の表面には絶縁被覆された導体２７が巻回されている。分割２次側コイル１２の筒体の貫通孔２０は、鉄心部材１３ａ及び固定具１４の断面積より大きく形成され、鉄心部材１３ａ及び固定具１４を通すことができる大きさとなっている。そこで、分割２次側コイル１２の貫通孔１８を鉄心部材１３ａ及び固定具１４に通して、順次、４個の分割２次側コイル１２を鉄心部材１３ａ及び固定具１４に挿入する。その後に、もう１個の鉄心部材１３ｂを固定具１４の内側に配置し、４個の分割２次側コイル１２を鉄心部材１３ａ、１３ｂ及び固定具１４に挿入した状態で、留め部１５ａ、１５ｂをボルト１６及びナット１７で固定する。これにより、図１に示した零相変流器が得られる。 As shown in FIG. 5, the divided secondary coil 12 is formed in a square cylinder shape, and a conductor 27 with an insulation coating is wound around the surface of the cylinder body. The through-hole 20 of the cylindrical body of the divided secondary coil 12 is formed larger than the cross-sectional area of the iron core member 13a and the fixture 14, and has a size through which the iron core member 13a and the fixture 14 can pass. Therefore, the through-hole 18 of the divided secondary coil 12 is passed through the iron core member 13a and the fixture 14, and the four divided secondary coils 12 are sequentially inserted into the iron core member 13a and the fixture 14. Thereafter, the other core member 13b is disposed inside the fixture 14, and the four divided secondary coils 12 are inserted into the core members 13a, 13b and the fixture 14, and the fastening portions 15a, 15b. Are fixed with bolts 16 and nuts 17. Thereby, the zero phase current transformer shown in FIG. 1 is obtained.

図１に示した零相変流器では、４個の分割２次側コイル１２ａ〜１２ｄは鉄心１１上で摺動可能となっており、鉄心１１上で配置位置が移動可能となっている。分割２次側コイル１２ａ〜１２ｄの配置位置は、直列接続された２次側コイル１２ａ〜１２ｄに発生する残留電流が最も小さくなる位置とする。 In the zero-phase current transformer shown in FIG. 1, the four divided secondary coils 12 a to 12 d are slidable on the iron core 11, and the arrangement position is movable on the iron core 11. The arrangement positions of the divided secondary coils 12a to 12d are positions where the residual current generated in the secondary coils 12a to 12d connected in series is the smallest.

２次側コイル１２ａ〜１２ｄに発生する残留電流が最も小さくなる位置の特定は、以下のようにして行う。図１に示した零相変流器の環状の鉄心１１で囲まれた空間に３相の導体を貫通し、その３相の導体に電流を流す。この状態で出力端子１９にシンクロスコープを接続して、２次側コイル１２ａ〜１２ｄに発生する残留電流を測定する。４個の分割２次側コイル１２ａ〜１２ｄを鉄心に沿って移動させ、測定される残留電流が最も小さくなる位置を特定する。例えば、４個の分割２次側コイル１２ａ〜１２ｄのうちの２個の分割２次側コイルを固定しておき、別の２個の分割２次側コイルを動かして、測定される残留電流が最も小さくなる位置を特定する。その後に、最初に固定しておいた２個の分割２次側コイルを動かして、さらに測定される残留電流が最も小さくなる位置があるかどうかを確認して、さらに小さくなる位置があるときは、後で動かした２個の分割２次側コイルをその位置に固定する。 The position where the residual current generated in the secondary side coils 12a to 12d becomes the smallest is specified as follows. A three-phase conductor is passed through the space surrounded by the annular core 11 of the zero-phase current transformer shown in FIG. 1, and a current is passed through the three-phase conductor. In this state, a synchroscope is connected to the output terminal 19, and the residual current generated in the secondary coils 12a to 12d is measured. The four divided secondary coils 12a to 12d are moved along the iron core, and the position where the measured residual current is minimized is specified. For example, of the four divided secondary coils 12a to 12d, two divided secondary coils are fixed, and another two divided secondary coils are moved so that the measured residual current is Specify the smallest position. After that, move the two divided secondary coils that were fixed first and check if there is a position where the measured residual current is the smallest. Then, the two divided secondary coils moved later are fixed at the positions.

以上の説明では、４個の分割２次側コイル１２ａ〜１２ｄの場合について説明したが、５個以上の分割２次側コイル１２としてもよいし、２個または３個の分割２次側コイル１２としてもよい。また、鉄心１１は、２個の鉄心部材１３ａ、１３ｂの場合について説明したが、３個以上に分割してもよい。さらに、分割２次側コイル１２の配置位置を特定する際に、測定する残留電流に含まれる高調波成分が無視できない場合には、フィルタを用いて残留電流を測定するようにしてもよい。 In the above description, the case of the four divided secondary coils 12a to 12d has been described. However, five or more divided secondary coils 12 may be used, or two or three divided secondary coils 12 may be used. It is good. Moreover, although the iron core 11 demonstrated the case of the two iron core members 13a and 13b, you may divide | segment into three or more. Furthermore, when the arrangement position of the divided secondary coil 12 is specified, if the harmonic component included in the residual current to be measured cannot be ignored, the residual current may be measured using a filter.

本発明の実施の形態によれば、複数個の円弧状の鉄心部材１３を接合させて環状に鉄心１１を形成しているので、既設の配電線路に容易に設置することができる。また、鉄心１１に装着する２次側コイル１２は、複数個に分割して移動可能に鉄心１１に配置し、分割された分割２次側コイル１２を鉄心１１に沿って移動させて２次側コイル１２に発生する残留電流が最も小さくなる位置を特定し、その特定された位置に分割２次側コイル１２を配置するので、残留電流が小さい零相変流器を提供できる。 According to the embodiment of the present invention, since a plurality of arc-shaped iron core members 13 are joined to form the iron core 11 in an annular shape, it can be easily installed on an existing distribution line. Further, the secondary coil 12 to be mounted on the iron core 11 is divided into a plurality of pieces and arranged on the iron core 11 so as to be movable. The divided secondary coil 12 is moved along the iron core 11 to move to the secondary side. Since the position where the residual current generated in the coil 12 becomes the smallest is specified and the divided secondary coil 12 is arranged at the specified position, a zero-phase current transformer with a small residual current can be provided.

その際に、配電線路の３相の導体が環状の鉄心１１で囲まれた空間を貫通する位置は、環状の鉄心１１で囲まれた空間のいずれの位置であってもよい。これは、３相の導体を環状の鉄心１１で囲まれた空間に貫通させた後に、分割２次側コイル１２を鉄心１１に沿って移動させて２次側コイル１２に発生する残留電流が最も小さくなる位置を特定するからである。 At that time, the position where the three-phase conductors of the distribution line pass through the space surrounded by the annular core 11 may be any position in the space surrounded by the annular core 11. This is because the residual current generated in the secondary coil 12 is the largest when the divided secondary coil 12 is moved along the iron core 11 after the three-phase conductor is passed through the space surrounded by the annular iron core 11. This is because the position to be reduced is specified.

いま、配電線路の導体の負荷電流が２３０Ａ、巻き数が４００回の２次側コイルで２次電流が１０ｍＡ（１次換算値４Ａ）の残留電流が発生する零相変流器に対して、巻き数１２５回の４個の分割２次側コイルを用いて本発明の実施の形態を適用したところ、２次電流が０．０２８ｍＡ（１次換算値１４．０ｍＡの残留電流とすることができ、０．３５％程度に残留電流を低減させることができた。この状況下においては、零相電流成分を５０ｍＡ通電した場合に、確実にその電流値（波形）を確認できる。従って、零相変流器の出力を入力として動作する地絡方向継電器の誤動作も防止でき、微地絡事故も高感度に検出できる。 For a zero-phase current transformer in which a residual current of a secondary current of 10 mA (primary conversion value 4 A) is generated by a secondary coil having a load current of 230 A and a winding number of 400 turns in a conductor of a distribution line, When the embodiment of the present invention is applied using four divided secondary coils having 125 windings, the secondary current can be set to 0.028 mA (residual current having a primary conversion value of 14.0 mA). In this situation, when the zero-phase current component is energized with 50 mA, the current value (waveform) can be confirmed with certainty. It is possible to prevent malfunction of the ground fault direction relay that operates using the output of the current transformer as input, and to detect a micro ground fault with high sensitivity.

本発明の実施の形態に係わる零相変流器の構成図。The block diagram of the zero phase current transformer concerning embodiment of this invention. 本発明の実施の形態に係わる零相変流器の鉄心部材の斜視図。The perspective view of the iron core member of the zero phase current transformer concerning an embodiment of the invention. 本発明の実施の形態に係わる零相変流器の鉄心の斜視図。The perspective view of the iron core of the zero phase current transformer concerning an embodiment of the invention. 本発明の実施の形態に係わる零相変流器の鉄心の形成過程の斜視図。The perspective view of the formation process of the iron core of the zero phase current transformer concerning embodiment of this invention. 本発明の実施の形態に係わる零相変流器の分割２次コイルの斜視図。The perspective view of the division | segmentation secondary coil of the zero phase current transformer concerning embodiment of this invention. 配電用変電所における配電系統の一例を示す系統図。The system diagram which shows an example of the power distribution system in the substation for power distribution.

符号の説明Explanation of symbols

１１…鉄心、１２…分割２次側コイル、１３…鉄心部材、１４…固定具、１５…留め部、１６…ボルト、１７…ナット、１８…配線、１９…出力端子、２０…貫通孔、２１…配電用変圧器、２２…母線、２３…配電線、２４…遮断器、２５…零相変流器、２６…地絡方向継電器、２７…導体 DESCRIPTION OF SYMBOLS 11 ... Iron core, 12 ... Split secondary coil, 13 ... Iron core member, 14 ... Fixing tool, 15 ... Fastening part, 16 ... Bolt, 17 ... Nut, 18 ... Wiring, 19 ... Output terminal, 20 ... Through-hole, 21 ... Distribution transformer, 22 ... Busbar, 23 ... Distribution line, 24 ... Circuit breaker, 25 ... Zero phase current transformer, 26 ... Ground fault relay, 27 ... Conductor

Claims

複数個の円弧状の鉄心部材を接合させて環状に形成された鉄心と、前記鉄心への配置位置が移動可能に装着される複数個の分割２次側コイルと、前記分割２次側コイルを直列接続して前記分割２次側コイルに発生した電流を出力する出力端子とを備え、前記分割２次側コイルを前記鉄心に沿って移動させ、前記２次側コイルに発生する残留電流が最も小さくなる前記分割２次側コイルの位置を特定し、その特定された位置に前記分割２次側コイルを配置することを特徴とする零相変流器。 An iron core formed in an annular shape by joining a plurality of arc-shaped iron core members, a plurality of divided secondary coils that are movably mounted on the iron core, and the divided secondary coils An output terminal for outputting a current generated in the split secondary coil by connecting in series, and moving the split secondary coil along the iron core so that the residual current generated in the secondary coil is the highest. A zero-phase current transformer characterized in that a position of the divided secondary side coil that becomes smaller is specified, and the divided secondary side coil is arranged at the specified position.