JP5449222B2 - DC leakage detection device - Google Patents
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Description
本発明は、電路の漏洩電流及び過度な漏電を非接触で検出できる直流漏電検出装置に関する。 The present invention relates to a DC leakage detection device that can detect a leakage current and excessive leakage in an electric circuit in a contactless manner.
電気機器や配線ケーブルは十分絶縁対策が施されているものの、経年劣化、ケーブルへの応力、機器の異なる取扱いなどにより絶縁劣化が生じ、絶縁劣化箇所を介して漏洩電流が流れ、人体への感電や発熱による火災事故が発生する要因となる。こうした漏電事故は、漏電検出センサである零相変流器（ＺＣＴ: Zero-phase Current Transformer）が内蔵された漏電遮断器や漏電リレーを電路に備えることで抑止することができる。ただし、零相変流器の動作原理上、交流の漏洩電流しか検出することができず、例えば太陽光発電システムや電気自動車システムといった直流電路系統においては、零相変流器が使用できない。 Although electrical equipment and wiring cables are adequately insulated, insulation deterioration occurs due to deterioration over time, stress on the cable, different handling of the equipment, etc., and leakage current flows through the insulation deterioration location, causing electric shock to the human body. Or cause a fire accident due to heat generation. Such a leakage accident can be suppressed by providing a circuit breaker or a leakage relay with a built-in zero-phase current transformer (ZCT) as a leakage detection sensor in the electric circuit. However, because of the operating principle of the zero-phase current transformer, only an AC leakage current can be detected. For example, a zero-phase current transformer cannot be used in a DC circuit system such as a photovoltaic power generation system or an electric vehicle system.
従来、直流電流センサとして、一部空隙部を設けた環状の磁性体コアに計測対象電流線を貫通させ、空隙部における磁界を、ホール素子や磁気抵抗素子（ＭＲ素子）等の磁気センサで検出し、センサ出力値から電流値を演算する手法が知られている。ただし、ホール素子や磁気抵抗素子（ＭＲ素子）は微小な磁界量を検出できないため、往路復路の差分電流や三相電流の和分電流といった零相電流、すなわち漏電を検出することは難しいのが現状である。 Conventionally, as a direct current sensor, a measurement target current line is passed through an annular magnetic core having a part of a gap, and a magnetic field in the gap is detected by a magnetic sensor such as a Hall element or a magnetoresistive element (MR element). A technique for calculating a current value from a sensor output value is known. However, since a Hall element or magnetoresistive element (MR element) cannot detect a minute magnetic field amount, it is difficult to detect a zero-phase current, that is, a leakage current, such as a differential current in the forward path or a sum of three-phase currents. Currently.
一方、ホール素子や磁気抵抗素子に比べて、磁界検出感度や温度依存性に優れる磁気センサとしてフラックスゲート磁気センサが知られている。例えば、特許文献１の第１図に示されているように、電流センサとして応用した形態であれば、漏電といった微小電流を検出するのにも適しており、動作原理上、直流および交流の電流が検出できる。 On the other hand, a fluxgate magnetic sensor is known as a magnetic sensor that is superior in magnetic field detection sensitivity and temperature dependency as compared with a Hall element and a magnetoresistive element. For example, as shown in FIG. 1 of Patent Document 1, the form applied as a current sensor is also suitable for detecting a minute current such as a leakage current. Can be detected.
従来のフラックスゲート電流センサは、閉磁路を形成した高透磁率を有する環状の磁性体コアに励磁巻線及び検出巻線を巻回し、被測定電流が流れる電流線を閉磁路内に貫通させた構造を有する。 In the conventional fluxgate current sensor, an excitation winding and a detection winding are wound around an annular magnetic core having a high magnetic permeability that forms a closed magnetic circuit, and a current line through which a current to be measured flows penetrates the closed magnetic circuit. It has a structure.
その動作原理について説明する。励磁巻線に交流励磁電流を通電し、磁性体コアを周期的に磁気飽和させる。被測定電流値が零である場合、励磁電流により発生する磁界変化は、磁性体コア材のＢ−Ｈ曲線の原点に関して対称となる。検出巻線にはファラデーの電磁誘導則に従い、検出巻線を巻回した磁性体コア内の磁束量の変化に伴い出力電圧が発生するため、磁性体コアが磁気飽和した磁界領域において出力電圧は零となる。すなわち、出力電圧は周期的に零電圧を有した波形となり、零電圧となる時間間隔は常に一定で、周期はＢ−Ｈ曲線の原点対称性から励磁周波数の２倍となる。 The operation principle will be described. An AC excitation current is passed through the excitation winding to periodically magnetically saturate the magnetic core. When the measured current value is zero, the magnetic field change generated by the excitation current is symmetric with respect to the origin of the BH curve of the magnetic core material. In accordance with Faraday's electromagnetic induction law, an output voltage is generated in the detection winding along with the change in the amount of magnetic flux in the magnetic core around which the detection winding is wound. It becomes zero. That is, the output voltage has a waveform having a zero voltage periodically, the time interval for the zero voltage is always constant, and the period is twice the excitation frequency due to the symmetry of the origin of the BH curve.
一方、被測定電流値が零でない場合、励磁電流により発生する励磁磁界に、被測定電流線から発生する磁界が重畳し、その磁界変化は、磁性体コア材のＢ−Ｈ曲線の原点に関して対称ではない。そのため、ある一定周期の励磁磁界で磁性体コアを励磁したとしても、出力電圧が零である時間間隔は一定とならず、磁界変化の挙動が正側および負側に変化した場合で異なるようになる。従って、出力電圧が零である時間間隔の差分から被測定電流値を演算することができ、被測定電流線での電流値を非接触で計測することができる。 On the other hand, when the measured current value is not zero, the magnetic field generated from the measured current line is superimposed on the exciting magnetic field generated by the exciting current, and the magnetic field change is symmetric with respect to the origin of the BH curve of the magnetic core material. is not. Therefore, even if the magnetic core is excited with an excitation magnetic field with a certain period, the time interval when the output voltage is zero is not constant, and the behavior of the magnetic field change differs depending on whether it changes to the positive side or the negative side. Become. Therefore, the measured current value can be calculated from the difference between the time intervals when the output voltage is zero, and the current value on the measured current line can be measured without contact.
さらに、フラックスゲート電流センサの検出精度を向上させるために、例えば特許文献２の図１に示されているような励磁磁界方向と検出磁界方向を直交させた構造や特許文献３の図２に示されているような２つの磁性体コアにそれぞれ逆向きの励磁磁界を印加し、検出巻線を一体巻回し差動化させた構造など、励磁磁界が検出磁界に与える影響を除去もしくは相殺させた構造が提案されている。 Further, in order to improve the detection accuracy of the fluxgate current sensor, for example, a structure in which the excitation magnetic field direction and the detection magnetic field direction are orthogonal to each other as shown in FIG. The effect of the excitation magnetic field on the detection magnetic field is eliminated or offset, such as a structure in which the opposite excitation magnetic field is applied to each of the two magnetic cores as described above, and the detection winding is integrally wound and differentiated. A structure has been proposed.
なお、特許文献４〜１１は、直流電流の非接触検出に関するものであるが、動作原理や演算手法の点で本発明と相違する。 Patent Documents 4 to 11 relate to non-contact detection of direct current, but are different from the present invention in terms of operation principle and calculation method.
フラックスゲート電流センサを漏電検出用の電流センサとして使用する場合、単相交流では往路復路の電流線をそれぞれ環状の磁性体コアに貫通させ、往路復路の電流線からそれぞれ生じる磁界の差分、もしくは３相交流では各電流線からそれぞれ生じる磁界の差分、すなわち比較的微弱な磁界をセンサで検出することになる。 When the fluxgate current sensor is used as a current sensor for detecting leakage, in a single-phase alternating current, the current wire of the forward return path is passed through the annular magnetic core, and the difference between the magnetic fields respectively generated from the current lines of the forward return path, or 3 In the phase alternating current, a difference in magnetic field generated from each current line, that is, a relatively weak magnetic field is detected by the sensor.
一方、復路電流がアースを介して流れた場合や、３相中１相ないしは２相の電流がアースを介して流れた場合など、地絡事故が生じて過漏電が発生している状況下では、往路電流線から生じる磁界や３相バランスがくずれた磁界は比較的強くなる。この場合でも、強磁界を検出して、事故発生から瞬時に対象電路の給電を遮断する必要がある。 On the other hand, when the return current flows through the ground or when the current of one or two phases out of the three phases flows through the ground, a ground fault has occurred and the over-leakage has occurred. The magnetic field generated from the outward current line and the magnetic field out of balance of the three phases become relatively strong. Even in this case, it is necessary to detect a strong magnetic field and to immediately cut off the power supply of the target circuit from the occurrence of the accident.
しかしながら、フラックスゲート電流センサの動作原理上、強磁界の印加によって磁性体コアが完全に磁気飽和してしまう環境下では、センサ出力電圧は零となってしまい、漏電有無の識別ができないという課題がある。 However, due to the operating principle of the fluxgate current sensor, in an environment where the magnetic core is completely magnetically saturated by the application of a strong magnetic field, the sensor output voltage becomes zero, and there is a problem that it is impossible to identify the presence or absence of a leakage. is there.
本発明の目的は、定格範囲内の漏洩電流を高感度に検出でき、定格範囲を超える地絡事故時が生じた場合でも地絡事故を確実に判定できる直流漏電検出装置を提供することである。 An object of the present invention is to provide a DC leakage detection device that can detect a leakage current within a rated range with high sensitivity and can reliably determine a ground fault even when a ground fault that exceeds the rated range occurs. .
上記目的を達成するために、本発明に係る直流漏電検出装置は、
閉磁路を形成する環状の磁性体コア、該磁性体コアに巻回された励磁巻線、および該磁性体コアに巻回された検出巻線を有し、少なくとも２本の被測定電流線が磁性体コアを貫通しているフラックスゲート電流センサと、
励磁巻線のインピーダンス変化に依存せずに所望の電流波形を励磁巻線に通電するための電流制御回路と、
励磁巻線に印加される電圧を検出する電圧検出回路と、
検出巻線の出力電圧から特定の周波数成分のみを抽出するフィルタ回路と、
電圧検出回路の出力およびフィルタ回路の出力に基づいて、過漏電の発生有無を判定する漏電判定回路とを備えたことを特徴とする。
In order to achieve the above object, a DC leakage detection apparatus according to the present invention includes:
An annular magnetic core forming a closed magnetic path, an excitation winding wound around the magnetic core, and a detection winding wound around the magnetic core, and at least two current lines to be measured are A fluxgate current sensor penetrating the magnetic core;
A current control circuit for energizing the excitation winding with a desired current waveform without depending on the impedance change of the excitation winding;
A voltage detection circuit for detecting a voltage applied to the excitation winding;
A filter circuit that extracts only a specific frequency component from the output voltage of the detection winding;
A leakage detecting circuit for determining whether or not excessive leakage has occurred is provided based on the output of the voltage detection circuit and the output of the filter circuit.
また本発明に係る直流漏電検出装置は、
空隙部を有する環状の磁性体コア、該磁性体コアに巻回された励磁巻線、および空隙部近傍に設置された磁気センサを有し、少なくとも２本の被測定電流線が磁性体コアを貫通している電流センサと、
励磁巻線のインピーダンス変化に依存せずに所望の電流波形を励磁巻線に通電するための電流制御回路と、
励磁巻線に印加される電圧を検出する電圧検出回路と、
磁気センサの出力電圧から励磁成分を除去する励磁成分除去回路と、
電圧検出回路の出力および励磁成分除去回路の出力に基づいて、過漏電の発生有無を判定する漏電判定回路とを備えたことを特徴とする。
The DC leakage detection device according to the present invention is
An annular magnetic core having a gap, an excitation winding wound around the magnetic core, and a magnetic sensor installed in the vicinity of the gap, and at least two current lines to be measured have a magnetic core A penetrating current sensor;
A current control circuit for energizing the excitation winding with a desired current waveform without depending on the impedance change of the excitation winding;
A voltage detection circuit for detecting a voltage applied to the excitation winding;
An excitation component removal circuit for removing the excitation component from the output voltage of the magnetic sensor;
A leakage detecting circuit for determining whether or not excessive leakage has occurred is provided based on the output of the voltage detection circuit and the output of the excitation component removal circuit.
また本発明に係る直流漏電検出装置は、
閉磁路を形成する環状の磁性体コア、該磁性体コアに巻回された励磁巻線、および該磁性体コアに巻回された検出巻線を有し、少なくとも２本の被測定電流線が磁性体コアを貫通しているフラックスゲート電流センサと、
励磁巻線のインピーダンス変化に依存せずに所望の電圧波形を励磁巻線に印加するための電圧制御回路と、
励磁巻線に通電される電流値を検出する電流検出回路と、
検出巻線の出力電圧から特定の周波数成分のみを抽出するフィルタ回路と、
電流検出回路の出力およびフィルタ回路の出力に基づいて、過漏電の発生有無を判定する漏電判定回路とを備えたことを特徴とする。
The DC leakage detection device according to the present invention is
An annular magnetic core forming a closed magnetic path, an excitation winding wound around the magnetic core, and a detection winding wound around the magnetic core, and at least two current lines to be measured are A fluxgate current sensor penetrating the magnetic core;
A voltage control circuit for applying a desired voltage waveform to the excitation winding without depending on the impedance change of the excitation winding;
A current detection circuit for detecting a current value energized in the excitation winding;
A filter circuit that extracts only a specific frequency component from the output voltage of the detection winding;
A leakage determining circuit for determining whether or not excessive leakage has occurred is provided based on the output of the current detection circuit and the output of the filter circuit.
また本発明に係る直流漏電検出装置は、
空隙部を有する環状の磁性体コア、該磁性体コアに巻回された励磁巻線、および空隙部近傍に設置された磁気センサを有し、少なくとも２本の被測定電流線が磁性体コアを貫通している電流センサと、
励磁巻線のインピーダンス変化に依存せずに所望の電圧波形を励磁巻線に印加するための電圧制御回路と、
励磁巻線に通電される電流値を検出する電流検出回路と、
磁気センサの出力電圧から励磁成分を除去する励磁成分除去回路と、
電流検出回路の出力および励磁成分除去回路の出力に基づいて、過漏電の発生有無を判定する漏電判定回路とを備えたことを特徴とする。
The DC leakage detection device according to the present invention is
An annular magnetic core having a gap, an excitation winding wound around the magnetic core, and a magnetic sensor installed in the vicinity of the gap, and at least two current lines to be measured have a magnetic core A penetrating current sensor;
A voltage control circuit for applying a desired voltage waveform to the excitation winding without depending on the impedance change of the excitation winding;
A current detection circuit for detecting a current value energized in the excitation winding;
An excitation component removal circuit for removing the excitation component from the output voltage of the magnetic sensor;
A leakage detecting circuit for determining whether or not excessive leakage has occurred is provided based on the output of the current detection circuit and the output of the excitation component removal circuit.
本発明によれば、磁性体コアが磁気飽和した場合、磁性体コアの比透磁率は空気の比透磁率とほぼ同等となるため、励磁巻線のインダクタンスが急激に低下し、結果的に励磁巻線のインピーダンスは急激に低下する。そこで、励磁巻線に印加される電圧または電流を検出することによって、磁性体コアの磁気飽和の有無を判定でき、その結果、差分電流または零相電流が大きい地絡事故、すなわち過漏電の発生有無を判定することができる。 According to the present invention, when the magnetic core is magnetically saturated, the relative permeability of the magnetic core is almost equal to the relative permeability of air, so that the inductance of the excitation winding decreases rapidly, resulting in excitation. The impedance of the winding decreases rapidly. Therefore, the presence or absence of magnetic saturation of the magnetic core can be determined by detecting the voltage or current applied to the excitation winding. As a result, a ground fault with a large differential current or zero-phase current, that is, occurrence of excessive leakage Presence / absence can be determined.
実施の形態１．
図１は、本発明の実施の形態１を示す構成図である。直流漏電検出装置１０１は、センサ駆動回路５１と、フラックスゲート電流センサ５２と、検出回路５３などを備える。
Embodiment 1 FIG.
FIG. 1 is a configuration diagram showing Embodiment 1 of the present invention. The DC leakage detection device 101 includes a sensor drive circuit 51, a flux gate current sensor 52, a detection circuit 53, and the like.
フラックスゲート電流センサ５２は、閉磁路を形成する環状の磁性体コア３と、磁性体コア３に巻回された励磁巻線１と、磁性体コア３に巻回された検出巻線２などを備える。磁性体コア３のほぼ中心を貫通するように、少なくとも２本の被測定電流線４が配置される。直流電路または単相交流電路の場合、往路と復路で計２本の被測定電流線４が配置され、３相交流電路の場合、Ｕ相、Ｖ相、Ｗ相の計３本の被測定電流線４が配置される。 The fluxgate current sensor 52 includes an annular magnetic core 3 that forms a closed magnetic circuit, an excitation winding 1 wound around the magnetic core 3, a detection winding 2 wound around the magnetic core 3, and the like. Prepare. At least two current lines 4 to be measured are arranged so as to penetrate substantially the center of the magnetic core 3. In the case of a DC circuit or a single-phase AC circuit, a total of two measured current lines 4 are arranged in the forward path and the return path, and in the case of a three-phase AC circuit, a total of three measured currents of U phase, V phase, and W phase Line 4 is placed.
センサ駆動回路５１は、所定の周波数ｆの基準交流波形を発生する交流電源５と、基準交流波形に比例した電流を励磁巻線１に通電するための電流制御回路６などを備える。 The sensor drive circuit 51 includes an AC power supply 5 that generates a reference AC waveform having a predetermined frequency f, a current control circuit 6 that supplies a current proportional to the reference AC waveform to the excitation winding 1, and the like.
検出回路５３は、励磁巻線１に印加される電圧を検出する電圧検出回路７と、検出巻線２の出力電圧から、特定の周波数成分、即ち、基準交流波形の周波数ｆの２倍に相当する周波数成分２ｆのみを抽出するフィルタ回路８と、電圧検出回路７の出力およびフィルタ回路８の出力に基づいて、被測定電流線４において過漏電の発生有無を判定する漏電判定回路９などを備える。 The detection circuit 53 corresponds to a voltage detection circuit 7 that detects a voltage applied to the excitation winding 1 and an output voltage of the detection winding 2 that corresponds to a specific frequency component, that is, twice the frequency f of the reference AC waveform. A filter circuit 8 for extracting only the frequency component 2f to be detected, a leakage determination circuit 9 for determining whether or not excessive leakage has occurred in the measured current line 4 based on the output of the voltage detection circuit 7 and the output of the filter circuit 8, and the like. .
図２は、フラックスゲート電流センサ５２の動作原理を示す説明図である。直流電源２１と負荷機器２２とが往路復路の電流線４を経由して電気接続されている。漏電を検出する場合、図２（ａ）に示すように、往路復路の電流線４が磁性体コア３の穴を貫通するように配置される。往路電流値と復路電流値が同一である場合、両方の電流線４に流れる電流の向きが逆であるため、電流線近傍に生じる磁界は相殺され、結果的に電流線近傍の磁界は零となる。一方、負荷機器２２で漏洩電流（漏電）２３が生じた場合、復路の電流線４に流れる電流値が往路の電流値に比べて小さくなるため、結果的に、往路電流値と復路電流値の差分に相当する磁界が電流線近傍に発生することになる。 FIG. 2 is an explanatory diagram showing the operating principle of the fluxgate current sensor 52. The DC power source 21 and the load device 22 are electrically connected via the current line 4 in the outward path. When detecting a leakage, the current line 4 in the forward return path is disposed so as to penetrate the hole of the magnetic core 3 as shown in FIG. When the forward current value and the return current value are the same, the directions of the currents flowing through both current lines 4 are opposite, so that the magnetic field generated near the current line is canceled out. As a result, the magnetic field near the current line is zero. Become. On the other hand, when a leakage current (leakage) 23 occurs in the load device 22, the current value flowing through the current line 4 on the return path is smaller than the current value on the return path. A magnetic field corresponding to the difference is generated in the vicinity of the current line.
本実施形態では、電流線近傍に生じる磁界を非接触で検出するセンサとして、フラックスゲート磁気センサの技術を応用している。フラックスゲート磁気センサは、ホール素子や磁気抵抗素子（ＭＲ素子やＧＭＲ素子）といった磁気センサに比べてより微小な磁界を検出することができ、温度依存性も良いことが知られている。 In the present embodiment, the technology of a fluxgate magnetic sensor is applied as a sensor that detects a magnetic field generated near the current line in a non-contact manner. It is known that the fluxgate magnetic sensor can detect a smaller magnetic field and has better temperature dependency than a magnetic sensor such as a Hall element or a magnetoresistive element (MR element or GMR element).
図２（ｂ）は、動作説明のために、１本の電流線４が磁性体コア３を貫通する場合を示している。フラックスゲート電流センサ５２は、例えば、珪素鋼板やＰＣパーマロイといった高透磁率材料からなる環状の磁性体コア３に、励磁巻線１及び検出巻線２を巻回した構造である。励磁巻線１には交流電流を通電し、磁性体コア３が周期的に磁気飽和するように励磁する。 FIG. 2B shows a case where one current line 4 penetrates the magnetic core 3 for explaining the operation. The fluxgate current sensor 52 has a structure in which an excitation winding 1 and a detection winding 2 are wound around an annular magnetic core 3 made of a high magnetic permeability material such as a silicon steel plate or PC permalloy. An alternating current is applied to the excitation winding 1 to excite the magnetic core 3 so as to be periodically magnetically saturated.
図３は、励磁磁界と磁性体コア３の磁束密度との関係を示す説明図であり、図３（ａ）は被測定電流値が零である場合、図３（ｂ）は被測定電流値が零でない場合を示す。図４は、検出巻線２の出力電圧波形を示すグラフである。 FIG. 3 is an explanatory diagram showing the relationship between the excitation magnetic field and the magnetic flux density of the magnetic core 3. FIG. 3 (a) shows a case where the measured current value is zero, and FIG. 3 (b) shows the measured current value. Indicates that is not zero. FIG. 4 is a graph showing an output voltage waveform of the detection winding 2.
電流制御回路６が基準交流波形に対応した電流を励磁巻線１に通電した状態で、被測定電流値が零の場合、図３（ａ）に示すように、正負対称の励磁磁界３１が磁性体コア３に印加される。磁性体コア３は、ある一定以上の磁界に対して磁束密度が増加しない磁気特性（Ｂ−Ｈ特性）３２を有するため、励磁磁界３１が一定レベルを超えた時点で磁束密度が飽和した波形を示す磁束変化３３が得られる。検出巻線２は、ファラデーの電磁誘導則に従って、磁性体コア内の磁束変化３３に応じた電圧を出力する。 When the current control circuit 6 supplies a current corresponding to the reference AC waveform to the excitation winding 1 and the current value to be measured is zero, as shown in FIG. Applied to the body core 3. Since the magnetic core 3 has a magnetic characteristic (BH characteristic) 32 in which the magnetic flux density does not increase with respect to a certain or higher magnetic field, a waveform in which the magnetic flux density is saturated when the exciting magnetic field 31 exceeds a certain level. The magnetic flux change 33 shown is obtained. The detection winding 2 outputs a voltage corresponding to the magnetic flux change 33 in the magnetic core according to Faraday's electromagnetic induction law.
図４（ａ）に示すように、磁性体コア３の磁束密度が飽和した期間では検出巻線２の出力電圧は零になり、磁束変化３３の正および負の傾斜に対応するように正および負の電圧値が交互に現れる。磁性体コア３の磁気特性が原点に関して対称であるため、検出巻線２の出力電圧は、励磁磁界周波数ｆの２倍に相当する周波数成分２ｆが発生することが判る。そこで、フィルタ回路８において、例えば、バンドパスフィルタなどを用いて、出力電圧波形から周波数成分２ｆを抽出することによって、被測定電流値を演算することができる。 As shown in FIG. 4A, during the period when the magnetic flux density of the magnetic core 3 is saturated, the output voltage of the detection winding 2 becomes zero, and positive and negative so as to correspond to the positive and negative gradients of the magnetic flux change 33. Negative voltage values appear alternately. Since the magnetic characteristics of the magnetic core 3 are symmetrical with respect to the origin, it can be seen that the output voltage of the detection winding 2 generates a frequency component 2f corresponding to twice the excitation magnetic field frequency f. Therefore, the filter circuit 8 can calculate the measured current value by extracting the frequency component 2f from the output voltage waveform using, for example, a bandpass filter.
一方、被測定電流値が零でない場合、電流線近傍では相殺されず残った磁界が生じることになる。そのため、電流線４から生じる磁界が励磁磁界に重畳され、図３（ｂ）に示すように、バイアス磁界を有した交流磁界３４が磁性体コア３に印加される。このとき磁束密度の飽和期間が正側および負側で相違するようになり、検出巻線２の出力電圧は、図４（ｂ）に示すように、零電圧の時間間隔が一定ではなく、バイアス磁界の極性に応じて異なる波形になる。こうした変化は、フィルタ回路８において出力電圧波形から周波数成分２ｆを抽出することによって、被測定電流値を演算することができる。 On the other hand, when the measured current value is not zero, a magnetic field that remains without being canceled in the vicinity of the current line is generated. Therefore, the magnetic field generated from the current line 4 is superimposed on the exciting magnetic field, and an alternating magnetic field 34 having a bias magnetic field is applied to the magnetic core 3 as shown in FIG. At this time, the saturation period of the magnetic flux density is different between the positive side and the negative side, and the output voltage of the detection winding 2 is not constant as shown in FIG. The waveform varies depending on the polarity of the magnetic field. For such a change, the current value to be measured can be calculated by extracting the frequency component 2 f from the output voltage waveform in the filter circuit 8.
図５は、フラックスゲート電流センサ５２の入出力特性の一例を示すグラフである。縦軸はフィルタ回路８の出力電圧波形の実効値、横軸は被測定電流線４の漏洩電流の値であり、両者は比例関係にあることが判る。 FIG. 5 is a graph showing an example of input / output characteristics of the fluxgate current sensor 52. The vertical axis represents the effective value of the output voltage waveform of the filter circuit 8, and the horizontal axis represents the value of the leakage current of the current line 4 to be measured. It can be seen that the two are in a proportional relationship.
以上の説明では、磁性体コア３には歪みのない正弦波磁界を印加した場合を例示したが、磁性体コア３に印加する励磁磁界は、励磁巻線１に通電する電流値、励磁巻線数、磁性体コアの平均磁路長が既知であれば計算することが可能である。ただし、励磁巻線１は環状の磁性体コア３に巻いており、磁性体の比透磁率は、例えば、図６に示すように、印加する磁界強度に対して一定の値にはならない。すなわち、励磁巻線１に通電する電流値に応じて磁性体コアの比透磁率は変化するため、励磁電流は、図７（ａ）に示すように、歪んだ波形となる。 In the above description, the case where a sinusoidal magnetic field without distortion is applied to the magnetic core 3 is exemplified. However, the excitation magnetic field applied to the magnetic core 3 is the current value for energizing the excitation winding 1 and the excitation winding. The number can be calculated if the average magnetic path length of the magnetic core is known. However, the exciting winding 1 is wound around the annular magnetic core 3, and the relative magnetic permeability of the magnetic material does not become a constant value with respect to the applied magnetic field strength, as shown in FIG. 6, for example. That is, since the relative permeability of the magnetic core changes according to the current value supplied to the excitation winding 1, the excitation current has a distorted waveform as shown in FIG.
そこで、電流制御回路６として、励磁巻線３のインダクタンス、すなわちインピーダンス変化に依存しない励磁電流波形を供給できる回路、例えば、バイラテラル型電圧−電流変換回路で構成することが好ましい。この場合、例えば、基準交流波形として正弦波の電圧波形を電流制御回路６に入力した場合、励磁巻線１には歪みのない正弦波電流波形を通電することができる。 Therefore, the current control circuit 6 is preferably configured by a circuit that can supply an excitation current waveform that does not depend on the inductance of the excitation winding 3, that is, an impedance change, for example, a bilateral voltage-current conversion circuit. In this case, for example, when a sinusoidal voltage waveform is input to the current control circuit 6 as the reference AC waveform, the excitation winding 1 can be energized with a distortion-free sinusoidal current waveform.
上述のように、フラックスゲート電流センサ５２の動作原理上、計測できる電流範囲は、バイアス磁界が重畳した場合でも正負必ず磁気飽和が得られる磁界領域であるため、図８に示した範囲±αとなる。従って、範囲±αを超えるような大きなバイアス磁界が磁性体コア３に印加されると、漏洩電流を高精度に計測することができない。 As described above, because of the operating principle of the fluxgate current sensor 52, the current range that can be measured is a magnetic field region in which positive and negative magnetic saturation is always obtained even when a bias magnetic field is superimposed, and therefore the range ± α shown in FIG. Become. Therefore, when a large bias magnetic field exceeding the range ± α is applied to the magnetic core 3, the leakage current cannot be measured with high accuracy.
さて、電流センサとして運用する場合は、定格範囲外の計測精度を補償する必要は無く、仮に定格範囲外の電流を通電した場合にセンサが壊れないということが製品仕様に盛り込まれることが想定される。しかしながら、漏電センサとして運用する場合、電流センサとして運用する場合とは少し事情が異なり、往路復路の電流線４から生じる磁界の差分を検出する必要がある。 When operating as a current sensor, it is not necessary to compensate for measurement accuracy outside the rated range, and it is assumed that the product specification will include that the sensor will not break if current outside the rated range is energized. The However, when operating as a leakage sensor, the situation is slightly different from when operating as a current sensor, and it is necessary to detect the difference in the magnetic field generated from the current line 4 on the forward return path.
例えば、図２（ａ）で示すように、負荷機器２２からアースを介して漏電２３が生じ、復路電流値に比べて漏洩電流が大きい地絡事故、いわゆる過漏電が発生することも考えられる。この場合、復路電流による相殺が小さくなり、往路電流線から生じる磁界の大部分が磁性体コア３に印加されるため、磁性体コア３は完全に磁気飽和し、検出巻線２の出力電圧は常に零になる現象が生じることが予測できる。磁性体コア３が磁気飽和した場合、磁性体コア３の比透磁率は空気の比透磁率とほぼ同等となるため、励磁巻線１のインダクタンスが急激に低下し、結果的に励磁巻線１のインピーダンスは急激に低下する。このとき、電流制御回路６により励磁巻線１のインピーダンス変化に関わらず一定振幅の電流を励磁巻線１に通電しているため、オーム則に従い、励磁巻線１に印加する電圧が急激に低下する。 For example, as shown in FIG. 2A, it is conceivable that a leakage current 23 occurs from the load device 22 through the ground, and a ground fault, that is, a so-called overleakage current that has a larger leakage current than the return current value. In this case, the cancellation due to the return current is reduced, and most of the magnetic field generated from the forward current line is applied to the magnetic core 3, so that the magnetic core 3 is completely magnetically saturated and the output voltage of the detection winding 2 is It can be predicted that a phenomenon that is always zero occurs. When the magnetic core 3 is magnetically saturated, the relative permeability of the magnetic core 3 is substantially equal to the relative permeability of air, so that the inductance of the excitation winding 1 decreases rapidly, and as a result, the excitation winding 1 The impedance of the current drops rapidly. At this time, since a current having a constant amplitude is applied to the excitation winding 1 regardless of the impedance change of the excitation winding 1 by the current control circuit 6, the voltage applied to the excitation winding 1 rapidly decreases according to the Ohm law. To do.
そこで、電圧検出回路７が励磁巻線１に印加される電圧、例えば、励磁電圧波形のピーク値を検出し、漏電判定回路９は、検出されたピーク値の変化を判定することによって過漏電の発生有無を判定することができる。こうしたピーク検出回路は、例えば全波整流回路や平滑回路などから構成できる。 Therefore, the voltage detection circuit 7 detects the voltage applied to the excitation winding 1, for example, the peak value of the excitation voltage waveform, and the leakage detection circuit 9 determines the change in the detected peak value, thereby The presence or absence of occurrence can be determined. Such a peak detection circuit can be composed of, for example, a full-wave rectifier circuit or a smoothing circuit.
漏電判定回路９は、例えば、Ａ／Ｄコンバータ、マイクロプロセッサ、メモリなどで構成され、フィルタ回路８の出力信号および電圧検出回路７の出力信号をいずれもＡ／Ｄコンバータを介してデジタル信号としてメモリに取り込むことができる。電圧検出回路７の出力信号レベルが所定の定格範囲内（例えば、図８の±αに相当する範囲内）であれば、フィルタ回路８の出力信号から漏電量を演算できる。一方、電圧検出回路７の出力信号が所定の定格範囲外（例えば、図８の±αを超える範囲）であれば、地絡事故等による過漏電が発生したと考えられ、電圧検出回路７の出力信号から過漏電の発生有無を判定することができる。 The leakage determination circuit 9 includes, for example, an A / D converter, a microprocessor, a memory, and the like, and both the output signal of the filter circuit 8 and the output signal of the voltage detection circuit 7 are stored as digital signals via the A / D converter. Can be imported. If the output signal level of the voltage detection circuit 7 is within a predetermined rated range (for example, within a range corresponding to ± α in FIG. 8), the amount of leakage can be calculated from the output signal of the filter circuit 8. On the other hand, if the output signal of the voltage detection circuit 7 is out of a predetermined rated range (for example, a range exceeding ± α in FIG. 8), it is considered that an excessive leakage due to a ground fault or the like has occurred. It is possible to determine the occurrence of excessive leakage from the output signal.
過漏電の発生有りと判定した場合、図示はしていないが、演算した漏電量や過漏電の発生有無に応じて漏電遮断器や漏電リレーなどを用いて電路を遮断したり、リレー信号を接続機器に発令したりすることが可能である。代替として、漏電量を演算する必要がない場合は、コンパレータ等を用いて漏電量の２値判定を行って、地絡事故の有り無し判定を実施することも可能である。 If it is determined that there is overcurrent leakage, not shown, but the circuit is interrupted or a relay signal is connected using a leakage breaker or leakage relay depending on the amount of leakage calculated or the occurrence of excess leakage. It is possible to issue a command to the device. As an alternative, when it is not necessary to calculate the amount of leakage, it is possible to perform a binary determination of the amount of leakage using a comparator or the like to determine the presence or absence of a ground fault.
さらに、本実施形態では、電圧検出回路７が励磁巻線１に印加される電圧波形のピーク値を検出し、漏電判定回路９がこのピーク値の変化を判定する場合を例として説明したが、代替として、電圧検出回路７が励磁巻線１に印加される電圧波形の実効値を検出し、漏電判定回路９がこの実効値の変化を判定することによって、過漏電の発生有無を判定することも可能である。 Furthermore, in the present embodiment, the case where the voltage detection circuit 7 detects the peak value of the voltage waveform applied to the excitation winding 1 and the leakage determination circuit 9 determines the change in the peak value has been described as an example. As an alternative, the voltage detection circuit 7 detects the effective value of the voltage waveform applied to the excitation winding 1, and the leakage determination circuit 9 determines the change in the effective value, thereby determining the occurrence of overcurrent leakage. Is also possible.
実施の形態２．
図９は、本発明の実施の形態２を示す構成図である。直流漏電検出装置１０２は、センサ駆動回路５１と、電流センサ６２と、検出回路６３などを備える。
Embodiment 2. FIG.
FIG. 9 is a block diagram showing Embodiment 2 of the present invention. The DC leakage detection device 102 includes a sensor drive circuit 51, a current sensor 62, a detection circuit 63, and the like.
電流センサ６２は、図１０に示すように、空隙部を有する環状の磁性体コア１２と、磁性体コア１２に巻回された励磁巻線１１と、空隙部近傍に設置された磁気センサ１３などを備える。磁気センサ１３は、ホール素子や磁気抵抗素子（ＭＲ素子）などで構成される。磁性体コア１２のほぼ中心を貫通するように、少なくとも２本の被測定電流線４が配置される。直流電路または単相交流電路の場合、往路と復路で計２本の被測定電流線４が配置され、３相交流電路の場合、Ｕ相、Ｖ相、Ｗ相の計３本の被測定電流線４が配置される。 As shown in FIG. 10, the current sensor 62 includes an annular magnetic core 12 having a gap, an excitation winding 11 wound around the magnetic core 12, a magnetic sensor 13 installed in the vicinity of the gap, and the like. Is provided. The magnetic sensor 13 is composed of a Hall element, a magnetoresistive element (MR element), or the like. At least two current lines 4 to be measured are arranged so as to penetrate substantially the center of the magnetic core 12. In the case of a DC circuit or a single-phase AC circuit, a total of two measured current lines 4 are arranged in the forward path and the return path, and in the case of a three-phase AC circuit, a total of three measured currents of U phase, V phase, and W phase Line 4 is placed.
センサ駆動回路５１は、図１と同様に、所定の周波数ｆの基準交流波形を発生する交流電源５と、基準交流波形に比例した電流を励磁巻線１に通電するための電流制御回路６などを備える。 As in FIG. 1, the sensor drive circuit 51 includes an AC power source 5 that generates a reference AC waveform having a predetermined frequency f, a current control circuit 6 that supplies a current proportional to the reference AC waveform to the excitation winding 1, and the like. Is provided.
検出回路６３は、励磁巻線１に印加される電圧を検出する電圧検出回路７と、磁気センサ１３の出力電圧から励磁成分を除去する励磁成分除去回路１４と、電圧検出回路７の出力および励磁成分除去回路１４の出力に基づいて、被測定電流線４において過漏電の発生有無を判定する漏電判定回路９などを備える。 The detection circuit 63 includes a voltage detection circuit 7 that detects a voltage applied to the excitation winding 1, an excitation component removal circuit 14 that removes an excitation component from the output voltage of the magnetic sensor 13, and the output and excitation of the voltage detection circuit 7. Based on the output of the component removal circuit 14, a leakage determination circuit 9 for determining whether or not excessive leakage has occurred in the measured current line 4 is provided.
本実施形態では、磁気センサ１３を利用した電流センサ６２を使用しており、地絡事故等により過漏電が発生した場合、磁性体コア１２は磁気飽和する。ただし、ホール素子やＭＲ素子は出力信号が飽和するだけであり、零にはならない。 In the present embodiment, the current sensor 62 using the magnetic sensor 13 is used, and the magnetic core 12 is magnetically saturated when excessive leakage occurs due to a ground fault or the like. However, the Hall element and the MR element only saturate the output signal and do not become zero.
磁気センサ１３は、検出対象磁界だけでなく励磁磁界成分も検出してしまうため、検出回路６３に励磁成分除去回路１４を設けている。励磁成分除去回路１４として、例えば、励磁磁界の周波数成分ｆを除去するローパスフィルタが使用できる。 Since the magnetic sensor 13 detects not only the detection target magnetic field but also the excitation magnetic field component, the excitation circuit removing circuit 14 is provided in the detection circuit 63. As the excitation component removal circuit 14, for example, a low-pass filter that removes the frequency component f of the excitation magnetic field can be used.
また、磁性体コア１２の比透磁率が磁界強度に対して変化する場合、電流制御回路６として、励磁巻線３のインダクタンス、すなわちインピーダンス変化に依存しない励磁電流波形を供給できる回路、例えば、バイラテラル型電圧−電流変換回路で構成することが好ましい。この場合、例えば、基準交流波形として正弦波の電圧波形を電流制御回路６に入力した場合、励磁巻線１には歪みのない正弦波電流波形を通電することができる。 Further, when the relative permeability of the magnetic core 12 changes with respect to the magnetic field strength, the current control circuit 6 can supply an excitation current waveform independent of the inductance of the excitation winding 3, that is, impedance change, for example, It is preferable to use a lateral voltage-current conversion circuit. In this case, for example, when a sinusoidal voltage waveform is input to the current control circuit 6 as the reference AC waveform, the excitation winding 1 can be energized with a distortion-free sinusoidal current waveform.
電圧検出回路７は、励磁巻線１に印加される電圧波形のピーク値を検出し、漏電判定回路９がこのピーク値の変化を判定するように構成してもよく、あるいは、励磁巻線１に印加される電圧波形の実効値を検出し、漏電判定回路９がこの実効値の変化を判定するように構成してもよい。 The voltage detection circuit 7 may be configured to detect a peak value of a voltage waveform applied to the excitation winding 1 and the leakage determination circuit 9 to determine a change in the peak value, or the excitation winding 1 It is also possible to detect the effective value of the voltage waveform applied to, and the leakage determination circuit 9 determines the change in the effective value.
漏電判定回路９は、図１と同様に、例えば、Ａ／Ｄコンバータ、マイクロプロセッサ、メモリなどで構成され、フィルタ回路８の出力信号および電圧検出回路７の出力信号をいずれもＡ／Ｄコンバータを介してデジタル信号としてメモリに取り込むことができる。電圧検出回路７の出力信号レベルが所定の定格範囲内（例えば、図８の±αに相当する範囲内）であれば、フィルタ回路８の出力信号から漏電量を演算できる。一方、電圧検出回路７の出力信号が所定の定格範囲外（例えば、図８の±αを超える範囲）であれば、地絡事故等による過漏電が発生したと考えられ、電圧検出回路７の出力信号から過漏電の発生有無を判定することができる。 As in FIG. 1, the leakage determination circuit 9 is composed of, for example, an A / D converter, a microprocessor, a memory, and the like, and both the output signal of the filter circuit 8 and the output signal of the voltage detection circuit 7 Via a digital signal. If the output signal level of the voltage detection circuit 7 is within a predetermined rated range (for example, within a range corresponding to ± α in FIG. 8), the amount of leakage can be calculated from the output signal of the filter circuit 8. On the other hand, if the output signal of the voltage detection circuit 7 is out of a predetermined rated range (for example, a range exceeding ± α in FIG. 8), it is considered that an excessive leakage due to a ground fault or the like has occurred. It is possible to determine the occurrence of excessive leakage from the output signal.
過漏電の発生有りと判定した場合、図示はしていないが、演算した漏電量や過漏電の発生有無に応じて漏電遮断器や漏電リレーなどを用いて電路を遮断したり、リレー信号を接続機器に発令したりすることが可能である。代替として、漏電量を演算する必要がない場合は、コンパレータ等を用いて漏電量の２値判定を行って、地絡事故の有り無し判定を実施することも可能である。 If it is determined that there is overcurrent leakage, not shown, but the circuit is interrupted or a relay signal is connected using a leakage breaker or leakage relay depending on the amount of leakage calculated or the occurrence of excess leakage. It is possible to issue a command to the device. As an alternative, when it is not necessary to calculate the amount of leakage, it is possible to perform a binary determination of the amount of leakage using a comparator or the like to determine the presence or absence of a ground fault.
なお、上述の実施の形態１，２において、磁性体コアに対して励磁巻線や検出巻線を局所的に巻回した場合を例示したが、磁性体コアの全周に渡って均等に分布するように巻回してもよく、さらに、磁性体コアへの巻線応力を緩和させるために、樹脂製のケースを介在させてケースの上から巻線を巻回する形態でも構わない。 In the first and second embodiments described above, the case where the excitation winding and the detection winding are locally wound around the magnetic core is exemplified, but the magnetic core is evenly distributed over the entire circumference. Further, the winding may be wound from above the case with a resin case interposed in order to relieve the winding stress to the magnetic core.
また、実施の形態１，２において、直流漏電の場合を例示したが、交流漏電の場合でもＡ／Ｄコンバータのサンプリング条件を満足すれば問題なく適用可能であり、サンプリング条件は基準交流波形の周波数に基づいて決定できる。 Further, in the first and second embodiments, the case of DC leakage is illustrated, but even in the case of AC leakage, it can be applied without any problem as long as the sampling condition of the A / D converter is satisfied. The sampling condition is the frequency of the reference AC waveform. Can be determined based on
実施の形態３．
図１１は、本発明の実施の形態３を示す構成図である。直流漏電検出装置１０３は、センサ駆動回路５１と、フラックスゲート電流センサ５２と、検出回路６４などを備える。本実施形態は、実施の形態１と同様な構成を有するが、検出回路６４において位相シフト検出回路１０を追加している点で相違する。
Embodiment 3 FIG.
FIG. 11 is a block diagram showing Embodiment 3 of the present invention. The DC leakage detection device 103 includes a sensor drive circuit 51, a flux gate current sensor 52, a detection circuit 64, and the like. The present embodiment has the same configuration as that of the first embodiment, but is different in that a phase shift detection circuit 10 is added in the detection circuit 64.
検出回路６４は、励磁巻線１に印加される電圧を検出する電圧検出回路７と、電圧検出回路７で検出された電圧波形と交流電源５からの基準交流波形との間の位相シフト量を検出する位相シフト検出回路１０と、検出巻線２の出力電圧から、特定の周波数成分、即ち、基準交流波形の周波数ｆの２倍に相当する周波数成分２ｆのみを抽出するフィルタ回路８と、位相シフト検出回路１０の出力およびフィルタ回路８の出力に基づいて、被測定電流線４において過漏電の発生有無を判定する漏電判定回路９などを備える。 The detection circuit 64 detects the voltage applied to the excitation winding 1 and the phase shift amount between the voltage waveform detected by the voltage detection circuit 7 and the reference AC waveform from the AC power supply 5. A phase shift detection circuit 10 to detect, a filter circuit 8 that extracts only a specific frequency component, that is, a frequency component 2f corresponding to twice the frequency f of the reference AC waveform, from the output voltage of the detection winding 2, and a phase Based on the output of the shift detection circuit 10 and the output of the filter circuit 8, a leakage determination circuit 9 for determining whether or not excessive leakage occurs in the current line 4 to be measured is provided.
地絡事故等により過漏電が発生して磁性体コア３が磁気飽和した場合、実施の形態１で説明したように、励磁巻線１のインピーダンス低下によって励磁巻線１への印加電圧も低下する。このとき励磁巻線１への印加電圧波形の位相も変化する。本実施形態では、基準交流波形に対する印加電圧波形の位相変化を検出するための位相シフト検出回路１０を設けることによって、漏電判定回路９は過漏電の発生有無を判定することができる。 When excessive leakage occurs due to a ground fault or the like and the magnetic core 3 is magnetically saturated, as described in the first embodiment, the voltage applied to the excitation winding 1 also decreases due to the impedance decrease of the excitation winding 1. . At this time, the phase of the voltage waveform applied to the excitation winding 1 also changes. In the present embodiment, by providing the phase shift detection circuit 10 for detecting the phase change of the applied voltage waveform with respect to the reference AC waveform, the leakage determination circuit 9 can determine whether or not excessive leakage has occurred.
なお本実施形態では、フラックスゲート電流センサ５２を用いた場合を例示したが、代替として、実施の形態２と同様に、空隙部を有する環状の磁性体コア１２と、磁性体コア１２に巻回された励磁巻線１１と、空隙部近傍に設置された磁気センサ１３を備えた電流センサ６２を用いても構わない。 In the present embodiment, the case where the fluxgate current sensor 52 is used is illustrated, but as an alternative, as in the second embodiment, the annular magnetic core 12 having a gap portion and the magnetic core 12 are wound. A current sensor 62 including the excited winding 11 and the magnetic sensor 13 installed near the gap may be used.
実施の形態４．
図１２は、本発明の実施の形態４を示す構成図である。直流漏電検出装置１０４は、センサ駆動回路６１と、フラックスゲート電流センサ５２と、検出回路６５などを備える。本実施形態は、実施の形態１と同様な構成を有するが、電流制御回路６の代わりに、励磁巻線１のインピーダンス変化に依存せずに所望の電圧波形を励磁巻線１に印加するための電圧制御回路１５を備え、さらに、電圧検出回路７の代わりに、励磁巻線１に通電される電流値を検出する電流検出回路１６を備えている点で相違する。
Embodiment 4 FIG.
FIG. 12 is a block diagram showing Embodiment 4 of the present invention. The DC leakage detection device 104 includes a sensor drive circuit 61, a flux gate current sensor 52, a detection circuit 65, and the like. The present embodiment has the same configuration as that of the first embodiment, but applies a desired voltage waveform to the excitation winding 1 without depending on the impedance change of the excitation winding 1 instead of the current control circuit 6. The voltage control circuit 15 is further provided, and a current detection circuit 16 for detecting a current value supplied to the excitation winding 1 is provided instead of the voltage detection circuit 7.
センサ駆動回路６１において、交流電源５は、所定の周波数ｆの基準交流波形を発生する。電流制御回路６は、基準交流波形に比例した電圧を励磁巻線１に印加する機能を有し、例えば、低い出力インピーダンスの増幅器などで構成でき、印加電圧は負荷のインピーダンス変化に依存しなくなる。 In the sensor drive circuit 61, the AC power supply 5 generates a reference AC waveform having a predetermined frequency f. The current control circuit 6 has a function of applying a voltage proportional to the reference AC waveform to the excitation winding 1, and can be constituted by, for example, an amplifier having a low output impedance, and the applied voltage does not depend on the impedance change of the load.
地絡事故等により過漏電が発生して磁性体コア３が磁気飽和した場合、実施の形態１で説明したように、励磁巻線１のインピーダンスが急激に低下する。このとき励磁巻線１への印加電圧が固定されているため、オーム則に従い、励磁巻線１に通電される電流値が急激に増加する。ただし、電流値の上限は、電圧制御回路１５の供給電源能力で決定される。 When excessive leakage occurs due to a ground fault or the like and the magnetic core 3 is magnetically saturated, as described in the first embodiment, the impedance of the excitation winding 1 rapidly decreases. At this time, since the voltage applied to the excitation winding 1 is fixed, the value of the current supplied to the excitation winding 1 rapidly increases according to the Ohm law. However, the upper limit of the current value is determined by the power supply capability of the voltage control circuit 15.
そこで、電流検出回路１６が励磁巻線１に通電される電流値、例えば、励磁電流波形のピーク値または実効値を検出し、漏電判定回路９は、検出されたピーク値または実効値の変化を判定することによって過漏電の発生有無を判定することができる。 Therefore, the current detection circuit 16 detects the current value energized in the excitation winding 1, for example, the peak value or effective value of the excitation current waveform, and the leakage determination circuit 9 detects the change in the detected peak value or effective value. By determining, it is possible to determine whether or not excessive leakage has occurred.
なお本実施形態では、フラックスゲート電流センサ５２を用いた場合を例示したが、代替として、実施の形態２と同様に、空隙部を有する環状の磁性体コア１２と、磁性体コア１２に巻回された励磁巻線１１と、空隙部近傍に設置された磁気センサ１３を備えた電流センサ６２を用いても構わない。 In the present embodiment, the case where the fluxgate current sensor 52 is used is illustrated, but as an alternative, as in the second embodiment, the annular magnetic core 12 having a gap portion and the magnetic core 12 are wound. A current sensor 62 including the excited winding 11 and the magnetic sensor 13 installed near the gap may be used.
実施の形態５．
図１３は、本発明の実施の形態５を示す構成図である。直流漏電検出装置１０５は、センサ駆動回路６１と、フラックスゲート電流センサ５２と、検出回路６６などを備える。本実施形態は、実施の形態４と同様な構成を有するが、検出回路６６において位相シフト検出回路１７を追加している点で相違する。
Embodiment 5 FIG.
FIG. 13 is a block diagram showing Embodiment 5 of the present invention. The DC leakage detection device 105 includes a sensor drive circuit 61, a fluxgate current sensor 52, a detection circuit 66, and the like. This embodiment has the same configuration as that of the fourth embodiment, but is different in that a phase shift detection circuit 17 is added to the detection circuit 66.
検出回路６６は、励磁巻線１に通電される電流値を検出する電流検出回路１６と、電流検出回路１６で検出された電流波形と交流電源５からの基準交流波形との間の位相シフト量を検出する位相シフト検出回路１７と、検出巻線２の出力電圧から、特定の周波数成分、即ち、基準交流波形の周波数ｆの２倍に相当する周波数成分２ｆのみを抽出するフィルタ回路８と、位相シフト検出回路１７の出力およびフィルタ回路８の出力に基づいて、被測定電流線４において過漏電の発生有無を判定する漏電判定回路９などを備える。 The detection circuit 66 detects a current value supplied to the excitation winding 1, and a phase shift amount between the current waveform detected by the current detection circuit 16 and the reference AC waveform from the AC power supply 5. A phase shift detection circuit 17 that detects a specific frequency component, that is, a filter circuit 8 that extracts only a frequency component 2f corresponding to twice the frequency f of the reference AC waveform, from the output voltage of the detection winding 2; Based on the output of the phase shift detection circuit 17 and the output of the filter circuit 8, a leakage determination circuit 9 that determines whether or not excessive leakage has occurred in the measured current line 4 is provided.
地絡事故等により過漏電が発生して磁性体コア３が磁気飽和した場合、実施の形態４で説明したように、励磁巻線１のインピーダンス低下によって、励磁巻線１に通電される電流値が増加する。このとき励磁巻線１の励磁電流波形の位相も変化する。本実施形態では、基準交流波形に対する励磁電流波形の位相変化を検出するための位相シフト検出回路１１７を設けることによって、漏電判定回路９は過漏電の発生有無を判定することができる。 When over-leakage occurs due to a ground fault or the like and the magnetic core 3 is magnetically saturated, as described in the fourth embodiment, the value of the current supplied to the excitation winding 1 due to the impedance reduction of the excitation winding 1 Will increase. At this time, the phase of the excitation current waveform of the excitation winding 1 also changes. In this embodiment, by providing the phase shift detection circuit 117 for detecting the phase change of the excitation current waveform with respect to the reference AC waveform, the leakage determination circuit 9 can determine whether or not excessive leakage has occurred.
なお本実施形態では、フラックスゲート電流センサ５２を用いた場合を例示したが、代替として、実施の形態２と同様に、空隙部を有する環状の磁性体コア１２と、磁性体コア１２に巻回された励磁巻線１１と、空隙部近傍に設置された磁気センサ１３を備えた電流センサ６２を用いても構わない。 In the present embodiment, the case where the fluxgate current sensor 52 is used is illustrated, but as an alternative, as in the second embodiment, the annular magnetic core 12 having a gap portion and the magnetic core 12 are wound. A current sensor 62 including the excited winding 11 and the magnetic sensor 13 installed near the gap may be used.
１，１１ 励磁巻線、 ２ 検出巻線、 ３，１２ 磁性体コア、
４ 被測定電流線、 ５ 交流電源、 ６ 電流制御回路、 ７ 電圧検出回路、
８ フィルタ回路、 ９ 漏電判定回路、 １０，１７ 位相シフト回路、
１３ 磁気センサ、 １４ 励磁成分除去回路、 １５ 電圧制御回路、
１６ 電流検出回路、 ２１ 直流電源、 ２２ 負荷機器、
２３ 漏洩電流（漏電）、 ３１ 励磁磁界、 ３２ 磁気特性（Ｂ−Ｈ特性）、
３３ 磁束変化、 ３４ バイアス磁界が重畳した励磁磁界、 ３５ 磁束変化、
５１，６１ センサ駆動回路、 ５２ フラックスゲート電流センサ、
５３，６３，６４，６５，６６ 検出回路、 １０１〜１０５ 直流漏電検出装置。
1,11 excitation winding, 2 detection winding, 3,12 magnetic core,
4 current line to be measured, 5 AC power supply, 6 current control circuit, 7 voltage detection circuit,
8 Filter circuit, 9 Leakage determination circuit, 10, 17 Phase shift circuit,
13 Magnetic sensor, 14 Excitation component removal circuit, 15 Voltage control circuit,
16 Current detection circuit, 21 DC power supply, 22 Load equipment,
23 Leakage current (leakage), 31 Exciting magnetic field, 32 Magnetic characteristics (BH characteristics),
33 Magnetic flux change, 34 Excitation magnetic field superimposed with bias magnetic field, 35 Magnetic flux change,
51, 61 sensor drive circuit, 52 fluxgate current sensor,
53, 63, 64, 65, 66 detection circuit, 101-105 DC leakage detection device.
Claims (10)
励磁巻線のインピーダンス変化に依存せずに所望の電流波形を励磁巻線に通電するための電流制御回路と、
励磁巻線に印加される電圧を検出する電圧検出回路と、
検出巻線の出力電圧から特定の周波数成分のみを抽出するフィルタ回路と、
電圧検出回路の出力およびフィルタ回路の出力に基づいて、過漏電の発生有無を判定する漏電判定回路とを備えたことを特徴とする直流漏電検出装置。 An annular magnetic core forming a closed magnetic path, an excitation winding wound around the magnetic core, and a detection winding wound around the magnetic core, and at least two current lines to be measured are A fluxgate current sensor penetrating the magnetic core;
A current control circuit for energizing the excitation winding with a desired current waveform without depending on the impedance change of the excitation winding;
A voltage detection circuit for detecting a voltage applied to the excitation winding;
A filter circuit that extracts only a specific frequency component from the output voltage of the detection winding;
A DC leakage detection apparatus comprising: a leakage determination circuit that determines whether or not excessive leakage occurs based on an output of a voltage detection circuit and an output of a filter circuit.
励磁巻線のインピーダンス変化に依存せずに所望の電流波形を励磁巻線に通電するための電流制御回路と、
励磁巻線に印加される電圧を検出する電圧検出回路と、
磁気センサの出力電圧から励磁成分を除去する励磁成分除去回路と、
電圧検出回路の出力および励磁成分除去回路の出力に基づいて、過漏電の発生有無を判定する漏電判定回路とを備えたことを特徴とする直流漏電検出装置。 An annular magnetic core having a gap, an excitation winding wound around the magnetic core, and a magnetic sensor installed in the vicinity of the gap, and at least two current lines to be measured have a magnetic core A penetrating current sensor;
A current control circuit for energizing the excitation winding with a desired current waveform without depending on the impedance change of the excitation winding;
A voltage detection circuit for detecting a voltage applied to the excitation winding;
An excitation component removal circuit for removing the excitation component from the output voltage of the magnetic sensor;
A DC leakage detection device comprising: a leakage determination circuit that determines whether or not excessive leakage has occurred based on an output of a voltage detection circuit and an output of an excitation component removal circuit.
漏電判定回路は、検出されたピーク値の変化を判定することによって、過漏電の発生有無を判定することを特徴とする請求項１または２記載の直流漏電検出装置。 The voltage detection circuit detects the peak value of the voltage waveform applied to the excitation winding,
3. The DC leakage detection device according to claim 1, wherein the leakage detection circuit determines whether or not excessive leakage has occurred by determining a change in the detected peak value.
漏電判定回路は、検出された実効値の変化を判定することによって、過漏電の発生有無を判定することを特徴とする請求項１または２記載の直流漏電検出装置。 The voltage detection circuit detects the effective value of the voltage waveform applied to the excitation winding,
3. The DC leakage detection device according to claim 1, wherein the leakage detection circuit determines whether or not excessive leakage has occurred by determining a change in the detected effective value.
電圧検出回路で検出された電圧波形と基準交流波形との間の位相シフト量を検出する位相シフト検出回路とをさらに備え、
漏電判定回路は、検出された位相シフト量の変化を判定することによって、過漏電の発生有無を判定することを特徴とする請求項１または２記載の直流漏電検出装置。 An AC power supply for supplying a reference AC waveform to the current control circuit;
A phase shift detection circuit for detecting a phase shift amount between the voltage waveform detected by the voltage detection circuit and the reference AC waveform;
3. The DC leakage detection device according to claim 1, wherein the leakage detection circuit determines whether or not excessive leakage has occurred by determining a change in the detected phase shift amount.
励磁巻線のインピーダンス変化に依存せずに所望の電圧波形を励磁巻線に印加するための電圧制御回路と、
励磁巻線に通電される電流値を検出する電流検出回路と、
検出巻線の出力電圧から特定の周波数成分のみを抽出するフィルタ回路と、
電流検出回路の出力およびフィルタ回路の出力に基づいて、過漏電の発生有無を判定する漏電判定回路とを備えたことを特徴とする直流漏電検出装置。 An annular magnetic core forming a closed magnetic path, an excitation winding wound around the magnetic core, and a detection winding wound around the magnetic core, and at least two current lines to be measured are A fluxgate current sensor penetrating the magnetic core;
A voltage control circuit for applying a desired voltage waveform to the excitation winding without depending on the impedance change of the excitation winding;
A current detection circuit for detecting a current value energized in the excitation winding;
A filter circuit that extracts only a specific frequency component from the output voltage of the detection winding;
A DC leakage detection apparatus comprising: a leakage determination circuit that determines whether or not excessive leakage has occurred based on an output of a current detection circuit and an output of a filter circuit.
励磁巻線のインピーダンス変化に依存せずに所望の電圧波形を励磁巻線に印加するための電圧制御回路と、
励磁巻線に通電される電流値を検出する電流検出回路と、
磁気センサの出力電圧から励磁成分を除去する励磁成分除去回路と、
電流検出回路の出力および励磁成分除去回路の出力に基づいて、過漏電の発生有無を判定する漏電判定回路とを備えたことを特徴とする直流漏電検出装置。 An annular magnetic core having a gap, an excitation winding wound around the magnetic core, and a magnetic sensor installed in the vicinity of the gap, and at least two current lines to be measured have a magnetic core A penetrating current sensor;
A voltage control circuit for applying a desired voltage waveform to the excitation winding without depending on the impedance change of the excitation winding;
A current detection circuit for detecting a current value energized in the excitation winding;
An excitation component removal circuit for removing the excitation component from the output voltage of the magnetic sensor;
A DC leakage detection device comprising: a leakage determination circuit that determines whether or not excessive leakage occurs based on an output of a current detection circuit and an output of an excitation component removal circuit.
漏電判定回路は、検出されたピーク値の変化を判定することによって、過漏電の発生有無を判定することを特徴とする請求項６または７記載の直流漏電検出装置。 The current detection circuit detects the peak value of the current waveform that is passed through the excitation winding,
8. The DC leakage detection device according to claim 6, wherein the leakage determination circuit determines whether or not excessive leakage has occurred by determining a change in the detected peak value.
漏電判定回路は、検出された実効値の変化を判定することによって、過漏電の発生有無を判定することを特徴とする請求項６または７記載の直流漏電検出装置。 The current detection circuit detects the effective value of the current waveform passed through the excitation winding,
8. The DC leakage detection device according to claim 6, wherein the leakage determination circuit determines whether or not excessive leakage has occurred by determining a change in the detected effective value.
電流検出回路で検出された電流波形と基準交流波形との間の位相シフト量を検出する位相シフト検出回路とをさらに備え、
漏電判定回路は、検出された位相シフト量の変化を判定することによって、過漏電の発生有無を判定することを特徴とする請求項６または７記載の直流漏電検出装置。 An AC power supply for supplying a reference AC waveform to the voltage control circuit;
A phase shift detection circuit for detecting a phase shift amount between the current waveform detected by the current detection circuit and the reference AC waveform;
8. The DC leakage detection device according to claim 6, wherein the leakage detection circuit determines whether or not excessive leakage has occurred by determining a change in the detected phase shift amount.
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