JP6749535B2 - Insulation monitoring device and test current generator and test device used therefor - Google Patents

Insulation monitoring device and test current generator and test device used therefor Download PDF

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JP6749535B2
JP6749535B2 JP2015213168A JP2015213168A JP6749535B2 JP 6749535 B2 JP6749535 B2 JP 6749535B2 JP 2015213168 A JP2015213168 A JP 2015213168A JP 2015213168 A JP2015213168 A JP 2015213168A JP 6749535 B2 JP6749535 B2 JP 6749535B2
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文典 阿部
文典 阿部
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Description

本発明は、絶縁監視装置に関し、特に、絶縁抵抗の測定精度を確認するための自己診断機能に関するものである。また本発明は、そのような絶縁監視装置の精度試験に用いられる試験電流発生装置ならびに試験装置に関するものである。 The present invention relates to an insulation monitoring device, and more particularly to a self-diagnosis function for confirming measurement accuracy of insulation resistance. The present invention also relates to a test current generator and a test device used for the accuracy test of such an insulation monitoring device.

電路の漏洩電流を監視するための絶縁監視装置が知られている。漏洩電流には対地静電容量に起因する地絡電流と絶縁抵抗に起因する地絡電流が含まれるが、漏電火災等を引き起こす原因は絶縁抵抗の低下であるため、絶縁抵抗に起因する漏洩電流を正確に検出できれば電路の絶縁状態を正確に把握でき、漏電火災等の大参事を未然に防止することが可能である。 Insulation monitoring devices are known for monitoring leakage currents in electrical circuits. The leakage current includes the ground fault current caused by the capacitance to ground and the ground fault current caused by the insulation resistance.However, the cause of a leakage fire is a decrease in the insulation resistance, so the leakage current caused by the insulation resistance If it can be accurately detected, it is possible to accurately grasp the insulation state of the electric circuit, and prevent major accidents such as an electric leakage fire.

絶縁監視装置には、絶縁監視が十分な精度で実施できているかどうかをチェックする自己診断機能が設けられており、この機能を用いた動作確認試験（精度試験）が定期的に行われている。精度試験は定期的な実施が義務化されており、使用頻度が少ない場合には一年や半年に１回、製造工場のように頻繁に使用される場所の装置では一カ月に１回やそれよりも短い期間で実施される。 The insulation monitoring device has a self-diagnosis function that checks whether insulation monitoring is performed with sufficient accuracy, and an operation confirmation test (accuracy test) using this function is performed regularly. .. Accuracy tests are required to be carried out on a regular basis. Once a year or half a year when the frequency of use is low, once a month or so for devices in places where they are frequently used, such as manufacturing plants. It will be carried out in a shorter period.

絶縁監視装置の精度試験に関し、例えば特許文献１には、被測定電路に流れる零相電流の影響を除去するために、通常の絶縁監視動作で被測定電路の接地線に接続されたトランスに印加される絶縁抵抗測定用の低周波電圧信号を変流器に直接印加する方法が記載されている。精度試験を実施する際に作業者が低周波電圧信号の供給先をトランスから変流器側に切り替えてから低周波電圧信号を印加し、低周波電圧信号の周波数を通過帯域とするフィルタを介して得られた電流の実効値により精度試験を実施する。 Regarding the accuracy test of the insulation monitoring device, for example, in Patent Document 1, in order to remove the influence of a zero-phase current flowing in the measured electric path, a voltage is applied to a transformer connected to the ground wire of the measured electric path by a normal insulation monitoring operation. A method of directly applying a low frequency voltage signal for insulation resistance measurement to a current transformer is described. When carrying out the accuracy test, the operator switches the supply destination of the low-frequency voltage signal from the transformer to the current transformer side, then applies the low-frequency voltage signal, and through the filter whose pass band is the frequency of the low-frequency voltage signal. An accuracy test is performed using the effective value of the current obtained as described above.

また特許文献２には、被測定電路に流れる零相電流の影響を除去するために、零相電流の抵抗性地絡電流成分を測定し、当該電流成分が予め重畳された試験電流を被測定電路に印加して精度試験を実施することが記載されている。 Further, in Patent Document 2, in order to remove the influence of the zero-phase current flowing in the measured circuit, a resistive ground fault current component of the zero-phase current is measured, and a test current in which the current component is preliminarily superimposed is measured. It is described that the accuracy test is performed by applying it to an electric circuit.

特許第４２８４６６８号公報Japanese Patent No. 4284668 特許第４７９６４２９号公報Japanese Patent No. 4796429

しかしながら、特許文献１に記載の方法では、被測定電路に流れる零相電流の影響は除去できるが、被測定電路に絶縁抵抗測定用の低周波電圧信号を印加するために必要なトランスが高価であり、低周波電圧信号の供給先をトランスから変流器側に切り替えるための作業も発生するという問題がある。 However, according to the method described in Patent Document 1, the effect of the zero-phase current flowing in the measured circuit can be removed, but the transformer required for applying the low-frequency voltage signal for measuring the insulation resistance to the measured circuit is expensive. Therefore, there is a problem that work for switching the supply destination of the low-frequency voltage signal from the transformer to the current transformer side also occurs.

特許文献２に記載の方法は、被測定電路の接地線に低周波電圧印加手段としてのトランスを設ける必要ないため設備コストの面で非常に有利である。しかしながら、被側定電路に流れる零相電流に応じて試験電流の大きさを変えるため、零相電流が大きい場合には試験電流も大きくなり、試験電流を増幅するアンプの消費電力が大きくなる。またアンプおよび電源回路の定格も上がるため、それらの部品価格も上がってしまう。さらに試験電流の大きさを内部的に一定（例えば５０ｍＡ）とする場合でも、実際に被測定電路に供給する試験電流の大きさが零相電流の大きさに応じて変わるため、試験電流が正しく供給されているかどうかをクランプメータ等で確認することができないという問題がある。 The method described in Patent Document 2 is very advantageous in terms of equipment cost because it is not necessary to provide a transformer as a low frequency voltage applying means on the ground wire of the measured electric path. However, since the magnitude of the test current is changed according to the zero-phase current flowing through the constant current path on the side to be tested, when the zero-phase current is large, the test current is also large and the power consumption of the amplifier for amplifying the test current is large. Moreover, since the ratings of the amplifier and the power supply circuit also increase, the price of those components also increases. Furthermore, even when the magnitude of the test current is internally constant (for example, 50 mA), the magnitude of the test current actually supplied to the measured circuit changes depending on the magnitude of the zero-phase current, so the test current is correct. There is a problem that it cannot be confirmed with a clamp meter or the like whether or not it is supplied.

本発明は上記課題を解決するためになされたものであり、精度試験実施時に零相電流の影響を除去し、試験電流をクランプメータでも測定可能で、小規模化かつ安価で作業効率の良い絶縁監視装置を提供することを目的とする。また本発明は、そのような絶縁監視装置の精度試験に用いられる試験電流発生装置ならびに試験装置を提供することを目的とする。 The present invention has been made in order to solve the above-mentioned problems, and eliminates the influence of zero-phase current during accuracy test execution, and the test current can be measured with a clamp meter as well. An object is to provide a monitoring device. Another object of the present invention is to provide a test current generator and a test device used for the accuracy test of such an insulation monitoring device.

上記課題を解決するため、本発明による絶縁監視装置は、被測定電路の接地線に磁気結合された零相電流センサと、前記被測定電路の商用電圧に同期した基準信号を出力する商用電圧同期手段と、前記零相電流センサによって検出された電流を取り込む電流取込手段と、前記電流取込手段が取り込んだ電流と前記基準信号とに基づいて抵抗性地絡電流成分を抽出する零相電流抽出手段と、前記基準信号と同一の周波数且つ一定の振幅を有し、Ｎ周期（ただしＮ≧２）ごとに位相変調された試験電流を生成する試験電流制御手段と、前記試験電流を前記零相電流センサに印加する試験電流印加手段と、前記試験電流が前記零相電流センサに印加されたとき前記零相電流センサによって検出された前記試験電流に起因する電流と前記零相電流に起因する電流とを含む合成電流を前記電流取込手段を介して入力し所定の演算処理を行ない前記試験電流の実効値を求める試験電流抽出手段とを備えることを特徴とする。 In order to solve the above problems, the insulation monitoring apparatus according to the present invention is a commercial voltage synchronization that outputs a zero-phase current sensor magnetically coupled to the ground wire of the measured circuit and a reference signal that is synchronized with the commercial voltage of the measured circuit. Means, a current fetching means for fetching the current detected by the zero phase current sensor, and a zero phase current for extracting a resistive ground fault current component based on the current fetched by the current fetching means and the reference signal. Extraction means, test current control means for generating a test current having the same frequency and a constant amplitude as the reference signal and phase-modulated every N cycles (where N≧2), and the test current to the zero. A test current applying means for applying to the phase current sensor, and a current due to the test current and the zero phase current detected by the zero phase current sensor when the test current is applied to the zero phase current sensor And a test current extracting unit for inputting a combined current including a current through the current fetching unit and performing a predetermined calculation process to obtain an effective value of the test current.

本発明によれば、被測定電路に流れる零相電流の影響を除去して精度試験を実施することが可能な絶縁監視装置を提供することができる。また、位相変調された試験電流を用いて精度試験を行うので、試験電流の振幅変動を抑えてクランプメータによる試験電流の確認を行うことができる。さらに、試験電流の振幅変動によるアンプの消費電力の増加を抑えることで小規模化かつ安価な絶縁監視装置を提供することができる。 According to the present invention, it is possible to provide an insulation monitoring device capable of performing the accuracy test by removing the influence of the zero-phase current flowing in the measured circuit. Further, since the accuracy test is performed using the phase-modulated test current, it is possible to suppress the amplitude variation of the test current and confirm the test current by the clamp meter. Further, it is possible to provide a small-scale and inexpensive insulation monitoring device by suppressing an increase in the power consumption of the amplifier due to the amplitude fluctuation of the test current.

本発明において、前記試験電流は、前記基準信号の位相に対して第１の位相β（β＝０を含む）を持つ第１の試験電流成分Ｉｔ１と、前記基準信号の位相に対して前記第１の位相βと異なる第２の位相β＋γ（ただしγ≠０）を持つ第２の試験電流成分Ｉｔ２とが、前記基準信号の周期のＮ倍（ただしＮ≧２）に相当する時間で交互に出力されたものであることが好ましい。これによれば、零相電流に影響されない位相変調された試験電流を用いることでその測定精度を高めることができる。 In the present invention, the test current has a first test current component It1 having a first phase β (including β=0) with respect to the phase of the reference signal, and the test current with respect to the phase of the reference signal. The second test current component I t2 having a second phase β+γ (where γ≠0) different from the first phase β is equal to N times the period of the reference signal (where N≧2). It is preferable that the signals are alternately output. According to this, the measurement accuracy can be improved by using the phase-modulated test current that is not affected by the zero-phase current.

本発明において、前記試験電流抽出手段は、前記電流取込手段が取り込んだ１周期分の前記合成電流を理想正弦波および理想余弦波とそれぞれ乗算し、前記第１の試験電流成分Ｉｔ１を含む前記合成電流ｉ１に前記理想正弦波および前記理想余弦波を乗算した結果をそれぞれＩｃ１、Ｉｓ１とし、前記第２の試験電流成分Ｉｔ２を含む前記合成電流ｉ２に前記理想正弦波および前記理想余弦波を乗算した結果をそれぞれＩｃ２、Ｉｓ２とし、前記基準信号の周期をＴとするとき、前記試験電流の実効値Ｉｔ／√２を
より求めることが好ましい。これによれば、被測定電路に流れる零相電流の影響を確実に除去し、小規模化かつ安価で作業効率の良い絶縁監視装置を提供することができる。 In the present invention, the test current extracting means multiplies the one cycle of the combined current captured by the current capturing means by an ideal sine wave and an ideal cosine wave, respectively, and includes the first test current component It1 . the combined current i 1 to the ideal sine wave and the results of the ideal cosine wave by multiplying the I c1, I s1 respectively, the ideal sine wave and the synthesized current i 2 including the second test current component I t2 When the results obtained by multiplying the ideal cosine wave are I c2 and I s2 , respectively, and the period of the reference signal is T, the effective value I t /√2 of the test current is
It is preferable to obtain more. According to this, it is possible to reliably remove the influence of the zero-phase current flowing in the measured electric circuit, and to provide an insulation monitoring device that is small in size, inexpensive, and has good work efficiency.

本発明において、前記Ｉｃ１、Ｉｓ１は、前記Ｉｃ２、Ｉｓ２よりもＮ周期前の前記合成電流の演算値であることが好ましい。またこの場合、前記Ｎは５以上２０以下であることが好ましい。同一位相による繰返し周期Ｎの値がこの範囲内であれば試験電流抽出手段による演算処理に必要なメモリ容量を抑えつつ試験電流の測定値の安定性を高めることができる。 In the present invention, the I c1 and I s1 are preferably calculated values of the combined current N cycles before the I c2 and I s2 . Further, in this case, the N is preferably 5 or more and 20 or less. If the value of the repetition period N with the same phase is within this range, the stability of the measured value of the test current can be improved while suppressing the memory capacity required for the calculation processing by the test current extraction means.

本発明において、前記第１の位相と前記第２の位相との位相差γは１８０度であることが好ましく、２０度以上４０度以下であることもまた好ましい。位相γが１８０度である場合には試験電流の測定精度を理論上最も高くすることができる。また、位相γが２０度以上４０度以下である場合には、試験電流の測定精度を確保しつつ、クランプメータ等で試験電流を測定する際の測定値のふらつきを防止することができる。 In the present invention, the phase difference γ between the first phase and the second phase is preferably 180 degrees, and more preferably 20 degrees or more and 40 degrees or less. When the phase γ is 180 degrees, the measurement accuracy of the test current can theoretically be the highest. Further, when the phase γ is 20 degrees or more and 40 degrees or less, it is possible to prevent the fluctuation of the measured value when measuring the test current with a clamp meter or the like while ensuring the measurement accuracy of the test current.

本発明において、前記抵抗性地絡電流成分の実効値または前記試験電流の実効値が前記所定の閾値以上のときにその旨を報知する報知手段をさらに備えることが好ましい。これによれば、零相電流の影響を受けない試験電流を用いて報知手段が正常に動作するか否かの精度試験を実施することができる。 In the present invention, it is preferable to further include an informing means for informing that when the effective value of the resistive ground fault current component or the effective value of the test current is equal to or more than the predetermined threshold value. According to this, it is possible to carry out an accuracy test of whether or not the notification means normally operates by using a test current that is not affected by the zero-phase current.

また、本発明による絶縁監視装置の試験電流発生装置は、被測定電路の接地線に磁気結合された零相電流センサによって検出された零相電流から抵抗性地絡電流成分を抽出して前記被測定電路の絶縁監視を行う絶縁監視装置の動作確認試験を活線状態で行うために前記零相電流センサに試験電流を供給する試験電流発生装置であって、前記被測定電路の商用電圧に同期した基準信号を生成する商用電圧同期手段と、前記基準信号と同一の周波数且つ一定の振幅を有し、Ｎ周期（ただしＮ≧２）ごとに位相変調された試験電流を生成する試験電流制御手段と、前記試験電流を前記零相電流センサに印加する前記試験電流印加手段とを備えることを特徴とする。 Further, the test current generator of the insulation monitoring apparatus according to the present invention extracts the resistive ground fault current component from the zero-phase current detected by the zero-phase current sensor magnetically coupled to the ground wire of the measured circuit, and extracts the resistive ground fault current component. A test current generator that supplies a test current to the zero-phase current sensor in order to perform an operation confirmation test of the insulation monitoring device that monitors the insulation of the measurement circuit in a live state, and is synchronized with the commercial voltage of the circuit to be measured. Commercial voltage synchronizing means for generating the reference signal, and test current control means for generating the test current having the same frequency and constant amplitude as the reference signal and phase-modulated every N cycles (where N≧2). And the test current applying means for applying the test current to the zero-phase current sensor.

さらにまた、本発明による絶縁監視装置の試験装置は、被測定電路の接地線に磁気結合された零相電流センサによって検出された零相電流から抵抗性地絡電流成分を抽出して前記被測定電路の絶縁監視を行う絶縁監視装置の動作確認試験を活線状態で行う試験装置であって、前記被測定電路の商用電圧に同期した基準信号を生成する商用電圧同期手段と、前記基準信号と同一の周波数且つ一定の振幅を有し、Ｎ周期（ただしＮ≧２）ごとに位相変調された試験電流を生成する試験電流制御手段と、前記試験電流を前記零相電流センサに印加する前記試験電流印加手段と、前記零相電流センサによって検出された前記試験電流に起因する電流と前記零相電流に起因する電流との合成電流を取り込む電流取込手段と、前記合成電流に対する所定の演算処理により前記試験電流の実効値を求める試験電流抽出手段と、前記抵抗性地絡電流成分の実効値または前記試験電流の実効値が所定の閾値以上のときにその旨を報知する報知手段とを備えることを特徴とする。 Furthermore, the test apparatus for the insulation monitoring apparatus according to the present invention extracts the resistive ground fault current component from the zero-phase current detected by the zero-phase current sensor magnetically coupled to the ground wire of the measured electric circuit, and measures the measured value. A test device for performing an operation confirmation test of an insulation monitoring device for monitoring insulation of a circuit in a live line state, wherein a commercial voltage synchronizing means for generating a reference signal synchronized with a commercial voltage of the circuit under measurement, and the reference signal Test current control means for generating a test current having the same frequency and a constant amplitude and phase-modulated every N cycles (where N≧2), and the test for applying the test current to the zero-phase current sensor. Current applying means, current taking-in means for taking in a combined current of the current resulting from the test current detected by the zero-phase current sensor and the current resulting from the zero-phase current, and a predetermined calculation process for the combined current A test current extracting means for obtaining an effective value of the test current, and an informing means for informing that when the effective value of the resistive ground fault current component or the effective value of the test current is a predetermined threshold value or more. It is characterized by

本発明によれば、精度試験実施時に零相電流の影響を除去し、試験電流をクランプメータでも測定可能で、小規模化かつ安価で作業効率の良い絶縁監視装置を提供することができる。また本発明によれば、そのような絶縁監視装置の精度試験に用いられる試験電流発生装置ならびに試験装置を提供することができる。 According to the present invention, it is possible to provide an insulation monitoring apparatus that eliminates the influence of zero-phase current when performing an accuracy test and can measure the test current with a clamp meter, and that is small in size, inexpensive, and has good work efficiency. Further, according to the present invention, it is possible to provide a test current generating device and a test device used for an accuracy test of such an insulation monitoring device.

本発明の実施の形態による絶縁監視装置の構成を示すブロック図である。It is a block diagram which shows the structure of the insulation monitoring apparatus by embodiment of this invention. 基準信号に対する試験電流、零相電流および合成電流の波形図である。It is a wave form diagram of a test current, a zero-phase current, and a synthetic current with respect to a reference signal. 試験電流抽出手段１５による試験電流の抽出方法を説明するためのブロック図である。5 is a block diagram for explaining a method of extracting a test current by the test current extracting means 15. FIG. 試験電流抽出手段１５による処理を合成電流の波形と共に示す説明図である。It is explanatory drawing which shows the process by the test current extraction means 15 with the waveform of a synthetic current.

以下、添付図面を参照しながら、本発明の実施の形態について詳細に説明する。 Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

図１は、本発明の実施の形態による絶縁監視装置の構成を示すブロック図である。 FIG. 1 is a block diagram showing a configuration of an insulation monitoring device according to an embodiment of the present invention.

図１に示すように、絶縁監視装置１は例えば単相二線式の低圧配電線を監視対象とするものであり、被測定電路２の接地線３に磁気結合された零相電流センサＺＣＴと、商用電圧に同期した基準信号を出力する商用電圧同期手段１１と、試験電流の位相を制御する試験電流制御手段１２と、試験電流制御手段１２が生成した電流波形を増幅して零相電流センサＺＣＴに印加する試験電流印加手段１３と、商用周波数を通過帯域として零相電流センサＺＣＴによって検出された電流を取り込む電流取込手段１４と、電流取込手段１４が取り込んだ接地線３に流れる零相電流Ｉｏに起因する電流と試験電流Ｉｔに起因する電流との合成電流ＩＸから試験電流Ｉｔの実効値を抽出する試験電流抽出手段１５と、試験電流Ｉｔの実効値や警報状態を知らせる報知手段１６とを備えている。 As shown in FIG. 1, the insulation monitoring device 1 is for monitoring, for example, a single-phase two-wire low-voltage distribution line, and includes a zero-phase current sensor ZCT magnetically coupled to the ground wire 3 of the measured circuit 2. , A commercial voltage synchronizing means 11 for outputting a reference signal synchronized with a commercial voltage, a test current controlling means 12 for controlling a phase of a test current, and a zero-phase current sensor by amplifying a current waveform generated by the test current controlling means 12. The test current applying means 13 applied to the ZCT, the current taking means 14 for taking in the current detected by the zero-phase current sensor ZCT with the commercial frequency as the pass band, and the zero flowing in the ground wire 3 taken in by the current taking means 14. a test current extracting means 15 for extracting the effective value of the test current I t from the combined current I X of the current resulting from the current caused by the phase current I o the test current I t, the effective value or alarm test current I t An informing means 16 for informing the state is provided.

商用電圧同期手段１１は、被測定電路２の商用電圧をＡ／Ｄ変換して取り込んだ波形の位相またはコンパレータなどで取り込んだ位相を出力する。商用電圧を取り込むことが困難な場合は、水晶発振器などでタイミングを内部生成して位相を出力してもよい。商用電圧同期手段１１が取り込んだ位相は装置内部の基準信号の位相となる。 The commercial voltage synchronizing means 11 outputs the phase of the waveform acquired by A/D converting the commercial voltage of the measured electric circuit 2 or the phase acquired by a comparator or the like. If it is difficult to take in the commercial voltage, the timing may be internally generated by a crystal oscillator or the like to output the phase. The phase taken in by the commercial voltage synchronizing means 11 becomes the phase of the reference signal inside the device.

試験電流制御手段１２は、商用電圧と同じ周波数且つ振幅が一定の試験電流Ｉｔを生成する。試験電流ＩｔはＮ周期ごとに位相変調されており、Ｎ周期分の位相βの電流波形とＮ周期分の位相β＋γの電流波形とが交互に繰り返されたものである。 Test current control means 12, the same frequency and amplitude as the utility voltage to generate a test current I t. Test current I t is phase modulated for each N period, in which the current waveform of phase beta + gamma current waveform and N cycles of N periods of the phase beta was repeated alternately.

試験電流印加手段１３は、例えば反転増幅回路などのアナログ回路であり、試験電流制御手段１２が生成した試験電流Ｉｔを例えば５０ｍＡ（実効値）に増幅して零相電流センサＺＣＴに供給する。 Test current applying means 13 is, for example, an analog circuit such as an inverting amplifier circuit, for supplying a test current I t to the test current control means 12 has generated for example 50mA to amplify and zero-phase current sensor ZCT in rms.

電流取込手段１４は、例えば多重帰還型ＬＰＦなどのアナログ回路であり、零相電流センサＺＣＴを介して入力された電流をフィルタリングして商用周波数（５０Ｈｚまたは６０Ｈｚ）の電流を取り込む。特に、電流取込手段１４は、接地線３に流れる零相電流Ｉｏに起因する電流と試験電流Ｉｔに起因する電流との合成電流ＩＸを取り込む。 The current fetching means 14 is, for example, an analog circuit such as a multiple feedback type LPF, and filters the current inputted through the zero-phase current sensor ZCT to fetch the current of the commercial frequency (50 Hz or 60 Hz). In particular, the current capturing means 14 captures the combined current I X of the current due to the current and the test current I t due to the zero-phase current I o flowing through the ground line 3.

試験電流抽出手段１５は、電流取込手段１４から入力された接地線３に流れる零相電流Ｉｏに起因する電流と零相電流センサＺＣＴに供給された試験電流Ｉｔに起因する電流との合成電流ＩＸから試験電流Ｉｔの成分を抽出し、試験電流Ｉｔの実効値を算出する。なお試験電流抽出手段１５は、零相電流センサＺＣＴや電流取込手段１４に起因する試験電流Ｉｔの損失を考慮して試験電流Ｉｔの実効値を算出する。あるいは電流取込手段１４が零相電流センサＺＣＴ等に起因する試験電流Ｉｔの損失を補正してもよい。報知手段１６は、試験電流Ｉｔの実効値を適宜通知すると共に、試験電流Ｉｔの実効値が所定の閾値以上である場合にランプ表示などで報知する。 Test current extracting means 15, the current due to the test current I t which is supplied to the current and the zero-phase current sensor ZCT due to zero-phase current I o flowing through the ground line 3 input from the current capturing means 14 components of the test current I t from the combined current I X to extract, to calculate the effective value of the test current I t. Incidentally test current extracting means 15 calculates the effective value of considering test current I t loss test current I t due to the zero-phase current sensor ZCT and current capturing means 14. Or loss of the test current I t current capturing means 14 is caused by the zero-phase current sensor ZCT like may be corrected. Notifying means 16 notifies the effective value of the test current I t appropriately, the effective value of the test current I t is broadcast like lamp display if more than a predetermined threshold value.

絶縁監視装置１は、被測定電路２の接地線３に磁気結合された零相電流センサＺＣＴによって検出された零相電流から抵抗性地絡電流成分を抽出して被測定電路の絶縁監視を行う。被測定電路２の漏洩電流には対地静電容量Ｃ０に起因する地絡電流と絶縁抵抗Ｒ０に起因する地絡電流が含まれるが、漏電火災等を引き起こす原因は絶縁抵抗Ｒ０の低下であるため、絶縁監視装置１は絶縁抵抗Ｒ０に起因する地絡電流を監視する。絶縁監視装置１による通常の絶縁監視動作では、零相電流センサＺＣＴによって検出された電流から商用電圧と同位相の電流成分（抵抗性地絡電流成分）を零相電流抽出手段１７がベクトル演算よって抽出し、抵抗性地絡電流成分が所定の閾値以上である場合には報知手段１６によるその旨の報知が行われる。 The insulation monitoring device 1 extracts a resistive ground fault current component from the zero-phase current detected by the zero-phase current sensor ZCT magnetically coupled to the ground wire 3 of the measured circuit 2 and monitors the measured circuit for insulation. .. The leakage current of the measured circuit 2 includes a ground fault current caused by the capacitance C 0 to the ground and a ground fault current caused by the insulation resistance R 0 , but the cause of the earth leakage fire is a decrease in the insulation resistance R 0 . Therefore, the insulation monitoring device 1 monitors the ground fault current caused by the insulation resistance R 0 . In a normal insulation monitoring operation by the insulation monitoring device 1, the zero-phase current extraction means 17 performs vector calculation of a current component (resistive ground fault current component) having the same phase as the commercial voltage from the current detected by the zero-phase current sensor ZCT. When the resistive ground fault current component is extracted and is equal to or more than a predetermined threshold value, the notification means 16 notifies that effect.

本実施形態において、商用電圧同期手段１１、試験電流制御手段１２、試験電流印加手段１３、電流取込手段１４、試験電流抽出手段１５および報知手段１６は、絶縁監視装置の動作確認試験を活線状態で行う試験装置を構成している。このうち、商用電圧同期手段１１、試験電流制御手段１２および試験電流印加手段１３は、絶縁監視装置１の動作確認試験を活線状態で行うために零相電流センサＺＣＴに試験電流を供給する試験電流発生装置を構成している。絶縁監視装置１の精度試験では、零相電流センサＺＣＴに試験電流を供給すると共に、零相電流センサＺＣＴによって検出された電流から試験電流Ｉｔに起因する電流を抽出し、所定の演算処理によって試験電流Ｉｔの実効値が求められる。その後、報知手段１６によりランプ表示やサーバ通信などで試験電流の実効値や警報状態を知らせる。 In the present embodiment, the commercial voltage synchronizing means 11, the test current control means 12, the test current applying means 13, the current fetching means 14, the test current extracting means 15 and the notifying means 16 perform the live check of the operation of the insulation monitoring device. It constitutes a test device to be used in the state. Of these, the commercial voltage synchronization means 11, the test current control means 12, and the test current application means 13 are tests for supplying a test current to the zero-phase current sensor ZCT in order to perform an operation confirmation test of the insulation monitoring device 1 in a live state. It constitutes a current generator. The precision test of insulation monitoring device 1 supplies the test current to the zero-phase current sensor ZCT, it extracts the current due to the test current I t from the detected current by the zero-phase current sensor ZCT, the predetermined calculation process the effective value of the test current I t is obtained. After that, the notification means 16 notifies the effective value of the test current and the alarm state by lamp display or server communication.

図２は、基準信号に対する試験電流、零相電流および合成電流の波形図であって、（ａ）は基準信号（商用電圧）、（ｂ）は試験電流、（ｃ）は零相電流、（ｄ）は合成電流をそれぞれ示している。 FIG. 2 is a waveform diagram of a test current, a zero-phase current, and a combined current with respect to a reference signal. (a) is a reference signal (commercial voltage), (b) is a test current, (c) is a zero-phase current, ( Each of d) shows a combined current.

図２（ａ）および（ｂ）に示すように、試験電流制御手段１２は、商用電圧同期手段１１が取り込んだ基準信号に対して位相βを持つＮ周期分の試験電流成分（第１の試験電流成分）と、基準信号に対して位相β＋γを持つＮ周期分の試験電流成分（第２の試験電流成分）とを交互に繰り返し出力する。すなわち、試験電流制御手段１２は、基準点Ｐから最初のＮ周期は位相βの電流波形を出力し、次のＮ周期は位相β＋γの電流波形を出力し、また次のＮ周期は位相βの電流波形を出力し、さらに次のＮ周期は位相β＋γの波形を出力する。なお試験電流の波形は正弦波に限定されず、矩形波であってもよく、離散波形であってもよい。 As shown in FIGS. 2A and 2B, the test current control unit 12 includes the test current component for the N cycles having the phase β with respect to the reference signal captured by the commercial voltage synchronization unit 11 (first test). Current component) and a test current component (second test current component) for N cycles having a phase β+γ with respect to the reference signal are alternately and repeatedly output. That is, the test current control means 12 outputs the current waveform of the phase β in the first N cycle from the reference point P, outputs the current waveform of the phase β+γ in the next N cycle, and outputs the current waveform of the phase β in the next N cycle. The current waveform is output, and the waveform of phase β+γ is output for the next N cycles. The waveform of the test current is not limited to a sine wave, and may be a rectangular wave or a discrete waveform.

試験電流の位相の切り替え周期Ｎの値は２以上（Ｎ≧２）であれば特に限定されないが、Ｎが小さい場合には試験電流の位相が頻繁に切り替わるため不連続点が多くなり、試験電流をクランプメータ等で測定したときの測定値が安定しない。また、Ｎが大きい場合には試験電流の位相が頻繁に切り替わらないので測定値が安定するが、合成電流の演算値をＮ周期分保持する大容量のバッファメモリを使用しなければならない。以上を考慮すると、Ｎは５以上２０以下であることが好ましい。 The value of the cycle N for switching the phase of the test current is not particularly limited as long as it is 2 or more (N≧2). However, when N is small, the phase of the test current is frequently switched, so that the number of discontinuities increases and the test current increases. The measured value is not stable when measured with a clamp meter. Further, when N is large, the phase of the test current is not frequently switched, so the measured value is stable, but a large-capacity buffer memory that holds the calculated value of the combined current for N cycles must be used. Considering the above, N is preferably 5 or more and 20 or less.

位相βの値は特に限定されず、例えばβ＝０であってもよい。また位相γは第１の試験電流成分と第２の試験電流成分との位相差であって、その値は０度以外であれば特に限定されないが、位相γが０度に近いほど試験電流の測定誤差が大きくなり、位相γが１８０度のときに測定精度が理論上最も高くなることから、位相γは１８０度であることが好ましい。しかしながら、図１に示すようにクランプメータ１９を用いて試験電流の測定を行う場合、位相γを１８０度付近とした場合には試験電流の位相がダイナミックに変化することによってクランプメータ１９の表示値のふらつきが大きくなる。そのため、クランプメータ１９による試験電流の測定を考慮すると、実用面では位相γは５度以上４５度以下であることが好ましく、２０度以上４０度以下であることが特に好ましい。 The value of the phase β is not particularly limited, and may be β=0, for example. Further, the phase γ is a phase difference between the first test current component and the second test current component, and its value is not particularly limited as long as it is other than 0 degree. The phase γ is preferably 180 degrees because the measurement error becomes large and the measurement accuracy theoretically becomes highest when the phase γ is 180 degrees. However, when the test current is measured using the clamp meter 19 as shown in FIG. 1, when the phase γ is set to around 180 degrees, the phase of the test current dynamically changes, and thus the display value of the clamp meter 19 is changed. The fluctuation of the image becomes large. Therefore, in consideration of the measurement of the test current by the clamp meter 19, the phase γ is preferably 5 degrees or more and 45 degrees or less, and particularly preferably 20 degrees or more and 40 degrees or less in practical use.

零相電流が被測定電路２に流れている場合において、零相電流センサＺＣＴから試験電流を供給すると、零相電流センサＺＣＴを介して電流取込手段１４に取り込まれる電流は、図２（ｂ）に示す試験電流と図２（ｃ）に示す零相電流との合成電流となる。図２（ｄ）に示すように、合成電流の波形はＮ周期ごとに位相および振幅が変化した波形となり、振幅差は位相γが１８０度に近いほど大きくなる。試験電流抽出手段１５はこのような合成電流から試験電流を抽出する。 When a test current is supplied from the zero-phase current sensor ZCT in the case where the zero-phase current is flowing in the measured circuit 2, the current taken into the current drawing means 14 via the zero-phase current sensor ZCT is as shown in FIG. 2) and the zero-phase current shown in FIG. 2C. As shown in FIG. 2D, the waveform of the combined current is a waveform in which the phase and the amplitude change every N cycles, and the amplitude difference increases as the phase γ approaches 180 degrees. The test current extraction means 15 extracts a test current from such a combined current.

図３は、試験電流抽出手段１５による試験電流の抽出方法を説明するためのブロック図である。以下は、零相電流センサＺＣＴ及び電流取込手段１４が損失無く理想的に動作するものと仮定して、その原理を解説するものである。 FIG. 3 is a block diagram for explaining a method of extracting a test current by the test current extracting means 15. Below, the principle is explained assuming that the zero-phase current sensor ZCT and the current drawing means 14 operate ideally without loss.

図３に示すように、試験電流抽出手段１５は、電流取込手段１４が入力した零相電流Ｉｏと試験電流Ｉｔとの合成電流を理想正弦波と理想余弦波でそれぞれ積和演算する。位相βで得られた理想正弦波および理想余弦波による積和演算結果をそれぞれＩｃ１、Ｉｓ１とし、位相β＋γで得られた理想正弦波および理想余弦波による積和演算結果をそれぞれＩｃ２、Ｉｓ２とする。試験電流抽出手段１５は、Ｉｃ１、Ｉｓ１、Ｉｃ２、Ｉｓ２から試験電流の実効値Ｉｔ／√２を算出する。試験電流抽出手段１５による演算処理の詳細は下記のようになる。 As shown in FIG. 3, the test current extracting means 15, respectively product-sum operation at the ideal sine wave and an ideal cosine wave combined current of the zero-phase current I o of the current capturing means 14 inputs the test current I t .. Let I c1 and I s1 be the product-sum operation results of the ideal sine wave and the ideal cosine wave obtained in phase β, respectively, and let the product-sum operation results of the ideal sine wave and ideal cosine wave obtained in phase β+γ be I c2 and I c2 , respectively. I s2 . The test current extraction means 15 calculates the effective value I t /√2 of the test current from I c1 , I s1 , I c2 , and I s2 . The details of the arithmetic processing by the test current extraction means 15 are as follows.

まず、被測定電路に流れる零相電流ｉｏを（数２）とし、試験電流制御手段１２により位相βで波形制御され、試験電流印加手段１３により印加される試験電流ｉｔ１を（数３）とすると、零相電流センサＺＣＴで（数２）と（数３）が合成されて電流ｉ１（数４）が生成される。なおαは基準信号に対する零相電流ｉｏの位相差である。
First, the zero-phase current i o flowing through the circuit to be measured (the number 2), is a waveform controlled by the phase β by the test current control means 12, the test current i t1 (number 3) applied by the test current applying means 13 Then, the zero-phase current sensor ZCT combines (Equation 2) and (Equation 3) to generate the current i 1 (Equation 4). Note that α is the phase difference of the zero-phase current i o with respect to the reference signal.

この電流ｉ１（第１の合成電流成分）を電流取込手段１４により取得し、試験電流抽出手段１５により理想正弦波と掛け合わせた結果を（数５）、理想余弦波と掛け合わせた結果を（数６）とする。なおＴは基準信号の周期である。
This current i 1 (first combined current component) is acquired by the current capturing means 14 and is multiplied by the ideal sine wave by the test current extracting means 15 (Equation 5), and the result is multiplied by the ideal cosine wave. Is defined as (Equation 6). Note that T is the cycle of the reference signal.

次に、試験電流制御手段１２により位相β＋γで波形制御され、試験電流印加手段１３により印加される試験電流ｉｔ２を（数７）とすると、零相電流センサＺＣＴで（数２）と（数７）が合成されて電流ｉ２（数８）が生成される。
Then, the waveform control by the phase beta + gamma by the test current control means 12, when the test current i t2 applied by the test current applying means 13 and (7), zero-phase current sensor ZCT (number 2) and (Number 7) is combined to generate a current i 2 (Equation 8).

この電流ｉ２（第２の合成電流成分）を電流取込手段１４により取得し、試験電流抽出手段１５により理想正弦波と掛け合わせた結果を（数９）、理想余弦波と掛け合わせた結果を（数１０）とする。
This current i 2 (second combined current component) is acquired by the current capturing means 14 and is multiplied by the ideal sine wave by the test current extracting means 15 (Equation 9), and the result is multiplied by the ideal cosine wave. Is set to (Equation 10).

（数５）と（数９）の差分を（数１１）とし、（数６）と（数１０）の差分を（数１２）とする。
Let the difference between (Equation 5) and (Equation 9) be (Equation 11), and the difference between (Equation 6) and (Equation 10) be (Equation 12).

（数１１）と（数１２）の２乗和は（数１３）となるから、試験電流の実効値Ｉｔ／√２は（数１４）のように算出できる。
Since the sum of squares of (Equation 11) and (Equation 12) is (Equation 13), the effective value I t /√2 of the test current can be calculated as in (Equation 14).

図４は、試験電流抽出手段１５による処理を合成電流の波形と共に示す説明図である。 FIG. 4 is an explanatory diagram showing the processing by the test current extracting means 15 together with the waveform of the combined current.

図４に示すように、合成電流から試験電流の実効値Ｉｔ／√２を求める演算処理は、合成電流の１周期ごとに行われ、合成電流ＩＸに理想正弦波および理想余弦波をそれぞれ乗じた値は合成電流ＩＸの１周期ごとに算出され、バッファメモリに保持される。 As shown in FIG. 4, the calculation process for obtaining the effective value I t /√2 of the test current from the combined current is performed for each cycle of the combined current, and the ideal sine wave and the ideal cosine wave are respectively added to the combined current I X. The multiplied value is calculated for each cycle of the combined current I X and is stored in the buffer memory.

例えば図示のように、最初のＮ周期は位相βの試験電流の区間（図２参照）であるため"Ｉｃ１"および"Ｉｓ１"が１周期ごとに生成され、次のＮ周期は位相β＋γの試験電流の区間であるため"Ｉｃ２"および"Ｉｓ２"が１周期ごとに生成される。そして１周期目のときの２つの値（Ｉｃ１，Ｉｓ１）とＮ＋１周期目のときの２つの値（Ｉｃ２，Ｉｓ２）をそれぞれ使って（式１３）の演算をすることで、試験電流の１周期分の実効値を算出することができる。すなわち、（Ｉｃ１，Ｉｓ１）の検出位置ではＮ周期前の（Ｉｃ２，Ｉｓ２）を用いて演算が行われ、（Ｉｃ２，Ｉｓ２）の検出位置ではＮ周期前の（Ｉｃ１，Ｉｓ１）を用いて演算が行われる。そして、このようなＮ周期前の値を参照した演算を１周期ごとに行うことで、各周期で同じように試験電流の実効値を求めることができる。 For example, as shown in the figure, since the first N cycle is the section of the test current of the phase β (see FIG. 2), “I c1 ”and “I s1 ” are generated for each cycle, and the next N cycle is the phase β+γ. "I c2 "and "I s2 "are generated for each cycle because it is the test current section. Then, by using the two values (I c1 , I s1 ) in the first cycle and the two values (I c2 , I s2 ) in the N+1 cycle, respectively, the calculation of (Equation 13) is performed, and the test is performed. The effective value for one cycle of current can be calculated. That, (I c1, I s1) The detected position of the operation using the previous N periods (I c2, I s2) performed, (I c2, I s2) before N cycles at the detected position of (I c1 , I s1 ) is used to perform the calculation. Then, the effective value of the test current can be similarly obtained in each cycle by performing such calculation with reference to the value N cycles before in each cycle.

以上説明したように、本実施形態による絶縁監視装置１は、絶縁監視の精度をチェックする自己診断機能を有し、零相電流に影響されない試験電流を零相電流センサＺＣＴに供給して動作確認試験を行うので、試験電流の測定精度を高めることができる。また位相変調された試験電流を用いるとともに、試験電流と零相電流との合成電流に理想正弦波および理想余弦波で積和演算した結果から試験電流の実効値を算出しているので、試験電流の振幅変動を抑えてクランプメータによる試験電流の確認を容易に行うことができる。 As described above, the insulation monitoring apparatus 1 according to the present embodiment has the self-diagnosis function of checking the accuracy of insulation monitoring, and supplies the test current that is not affected by the zero-phase current to the zero-phase current sensor ZCT to confirm the operation. Since the test is performed, the measurement accuracy of the test current can be improved. In addition to using the phase-modulated test current, the effective value of the test current is calculated from the result of product-sum calculation of the combined current of the test current and zero-phase current with the ideal sine wave and ideal cosine wave. It is possible to easily confirm the test current with the clamp meter while suppressing the amplitude fluctuation of the.

以上、本発明の好ましい実施形態について説明したが、本発明は、上記の実施形態に限定されることなく、本発明の主旨を逸脱しない範囲で種々の変更が可能であり、それらも本発明の範囲内に包含されるものであることはいうまでもない。 Although the preferred embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications can be made without departing from the gist of the present invention. It goes without saying that it is included in the range.

例えば、上記実施形態においては、単相二線式の低圧配電線を被測定電路としたが、本発明はこれに限定されず、単相三線式または三相三線式の電路を監視対象としてもよい。 For example, in the above embodiment, the low-voltage distribution line of the single-phase two-wire system was used as the measured electric circuit, but the present invention is not limited to this, and the single-phase three-wire system or the three-phase three-wire circuit can also be monitored. Good.

１ 絶縁監視装置
２ 被測定電路
３ 接地線
１１ 商用電圧同期手段
１２ 試験電流制御手段
１３ 試験電流印加手段
１４ 電流取込手段
１５ 試験電流抽出手段
１６ 報知手段
１７ 零相電流抽出手段
１９ クランプメータ
Ｃ０ 対地静電容量
Ｉ１，ｉ１ 合成電流（第１の合成電流成分）
Ｉ２，ｉ２ 合成電流（第２の合成電流成分）
Ｉｏ，ｉｏ 零相電流
Ｉｔ 試験電流
Ｉｔ１，ｉｔ１ 第１の試験電流成分
Ｉｔ２，ｉｔ２ 第２の試験電流成分
ＩＸ 合成電流
Ｒ０ 絶縁抵抗
ＺＣＴ 零相電流センサ
α 基準信号に対する零相電流の位相差
β 試験電流の第１の位相
γ 試験電流の第１の位相と第２の位相との位相差 DESCRIPTION OF SYMBOLS 1 Insulation monitoring device 2 Measured electric circuit 3 Ground wire 11 Commercial voltage synchronizing means 12 Test voltage control means 13 Test current applying means 14 Current taking means 15 Test current extracting means 16 Notification means 17 Zero phase current extracting means 19 Clamp meter C 0 Ground capacitance I 1 , i 1 combined current (first combined current component)
I 2 , i 2 combined current (second combined current component)
I o, i o zero-phase current I t test current I t1, i t1 first test current component I t2, i t2 second test current component I X composite current R 0 Insulation Resistance ZCT zero-phase current sensor α reference signal Phase difference of zero-phase current with respect to β First phase of test current γ Phase difference between first phase and second phase of test current

Claims (8)

被測定電路の接地線に磁気結合された零相電流センサと、
前記被測定電路の商用電圧に同期した基準信号を出力する商用電圧同期手段と、
前記零相電流センサによって検出された電流を取り込む電流取込手段と、
前記電流取込手段が取り込んだ電流と前記基準信号とに基づいて抵抗性地絡電流成分を抽出する零相電流抽出手段と、
前記基準信号と同一の周波数且つ一定の振幅を有し、Ｎ周期（ただしＮ≧２）ごとに位相変調された試験電流を生成する試験電流制御手段と、
前記試験電流を前記零相電流センサに印加する試験電流印加手段と、
前記試験電流が前記零相電流センサに印加されたとき前記零相電流センサによって検出された前記試験電流に起因する電流と零相電流に起因する電流とを含む合成電流を前記電流取込手段を介して入力し所定の演算処理を行ない前記試験電流の実効値を求める試験電流抽出手段とを備え、
前記試験電流は、前記基準信号の位相に対して第１の位相β（β＝０を含む）を持つ第１の試験電流成分Ｉ ｔ１ と、前記基準信号の位相に対して前記第１の位相βと異なる第２の位相β＋γ（ただしγ≠０）を持つ第２の試験電流成分Ｉ ｔ２ とが、前記基準信号の周期のＮ倍（ただしＮ≧２）に相当する時間で交互に出力されたものであり、
前記試験電流抽出手段は、前記電流取込手段が取り込んだ１周期分の前記合成電流を理想正弦波および理想余弦波とそれぞれ乗算し、
前記第１の試験電流成分Ｉｔ１を含む前記合成電流ｉ１に前記理想正弦波および前記理想余弦波を乗算した結果をそれぞれＩｃ１、Ｉｓ１とし、
前記第２の試験電流成分Ｉｔ２を含む前記合成電流ｉ２に前記理想正弦波および前記理想余弦波を乗算した結果をそれぞれＩｃ２、Ｉｓ２とし、
前記基準信号の周期をＴとするとき、
前記試験電流の実効値Ｉｔ／√２を
により求めることを特徴とする絶縁監視装置。 A zero-phase current sensor magnetically coupled to the ground wire of the measured circuit,
A commercial voltage synchronizing means for outputting a reference signal synchronized with the commercial voltage of the circuit under test,
A current capturing means for capturing the current detected by the zero-phase current sensor,
Zero-phase current extraction means for extracting a resistive ground fault current component based on the current captured by the current capturing means and the reference signal;
A test current control unit that has the same frequency and a constant amplitude as the reference signal and that generates a test current that is phase-modulated every N cycles (where N≧2) ;
Test current applying means for applying the test current to the zero-phase current sensor,
When the test current is applied to the zero-phase current sensor, a combined current including a current caused by the test current detected by the zero-phase current sensor and a current caused by the zero-phase current is generated by the current capturing means. And a test current extracting means for determining an effective value of the test current by performing a predetermined arithmetic processing input through
The test current, a first test current component I t1 with (including beta = 0) a first phase beta with respect to the phase of the reference signal, the first phase relative to said reference signal phase a second test current component I t2 with beta different from the second phase beta + gamma (where gamma ≠ 0) is output alternately in a time corresponding to N times the period of the reference signal (where N ≧ 2) It was
The test current extracting means multiplies the combined current for one cycle captured by the current capturing means by an ideal sine wave and an ideal cosine wave, respectively,
The result of multiplying the ideal sine wave and the ideal cosine wave to the combined current i 1 including the first test current component I t1 and I c1, I s1 respectively,
The result of multiplying the ideal sine wave and the ideal cosine wave to the composite current i 2 including the second test current component I t2 and I c2, I s2 respectively,
When the cycle of the reference signal is T,
The effective value I t /√2 of the test current is
Insulation monitoring device and obtaining by. 前記Ｉｃ１、Ｉｓ１は、前記Ｉｃ２、Ｉｓ２よりもＮ周期前の前記合成電流の演算値である、請求項１に記載の絶縁監視装置。 The insulation monitoring device according to claim 1 , wherein the I c1 and I s1 are calculated values of the combined current N cycles before the I c2 and I s2 . 前記Ｎは５以上２０以下である、請求項１または２に記載の絶縁監視装置。 The insulation monitoring device according to claim 1 , wherein the N is 5 or more and 20 or less. 前記第１の位相と前記第２の位相との位相差γは１８０度である、請求項１ないし３のいずれか一項に記載の絶縁監視装置。 4. The insulation monitoring device according to claim 1 , wherein a phase difference γ between the first phase and the second phase is 180 degrees. 前記第１の位相と前記第２の位相との位相差γは２０度以上４０度以下である、請求項１ないし３のいずれか一項に記載の絶縁監視装置。 The insulation monitoring device according to claim 1 , wherein a phase difference γ between the first phase and the second phase is 20 degrees or more and 40 degrees or less. 前記抵抗性地絡電流成分の実効値または前記試験電流の実効値が所定の閾値以上のときにその旨を報知する報知手段をさらに備える、請求項１ないし５のいずれか一項に記載の絶縁監視装置。 The insulation according to any one of claims 1 to 5 , further comprising an informing means for informing that when the effective value of the resistive ground fault current component or the effective value of the test current is equal to or greater than a predetermined threshold value. Monitoring equipment. 被測定電路の接地線に磁気結合された零相電流センサによって検出された零相電流から抵抗性地絡電流成分を抽出して前記被測定電路の絶縁監視を行う絶縁監視装置の動作確認試験を活線状態で行うために前記零相電流センサに試験電流を供給する試験電流発生装置であって、
前記被測定電路の商用電圧に同期した基準信号を生成する商用電圧同期手段と、
前記基準信号と同一の周波数且つ一定の振幅を有し、Ｎ周期（ただしＮ≧２）ごとに位相変調された試験電流を生成する試験電流制御手段と、
前記試験電流を前記零相電流センサに印加する試験電流印加手段とを備え、
前記試験電流は、前記基準信号の位相に対して第１の位相β（β＝０を含む）を持つ第１の試験電流成分Ｉ ｔ１ と、前記基準信号の位相に対して前記第１の位相βと異なる第２の位相β＋γ（ただしγ≠０）を持つ第２の試験電流成分Ｉ ｔ２ とが、前記基準信号の周期のＮ倍（ただしＮ≧２）に相当する時間で交互に出力されたものであることを特徴とする絶縁監視装置の試験電流発生装置。 An operation confirmation test of an insulation monitoring device that extracts a resistance ground fault current component from the zero-phase current detected by a zero-phase current sensor magnetically coupled to the ground wire of the measured circuit and monitors the insulation of the measured circuit. A test current generator for supplying a test current to the zero-phase current sensor to perform in a live state,
A commercial voltage synchronizing means for generating a reference signal synchronized with the commercial voltage of the circuit under test,
A test current control unit that has the same frequency and a constant amplitude as the reference signal and that generates a test current that is phase-modulated every N cycles (where N≧2) ;
A test current applying means for applying the test current to the zero-phase current sensor ,
The test current, a first test current component I t1 with (including beta = 0) a first phase beta with respect to the phase of the reference signal, the first phase relative to said reference signal phase a second test current component I t2 with beta different from the second phase beta + gamma (where gamma ≠ 0) is output alternately in a time corresponding to N times the period of the reference signal (where N ≧ 2) A test current generator for an insulation monitoring device, which is characterized in that 被測定電路の接地線に磁気結合された零相電流センサによって検出された零相電流から抵抗性地絡電流成分を抽出して前記被測定電路の絶縁監視を行う絶縁監視装置の動作確認試験を活線状態で行う試験装置であって、
前記被測定電路の商用電圧に同期した基準信号を生成する商用電圧同期手段と、
前記基準信号と同一の周波数且つ一定の振幅を有し、Ｎ周期（ただしＮ≧２）ごとに位相変調された試験電流を生成する試験電流制御手段と、
前記試験電流を前記零相電流センサに印加する試験電流印加手段と、
前記零相電流センサによって検出された前記試験電流に起因する電流と前記零相電流に起因する電流との合成電流を取り込む電流取込手段と、
前記合成電流に対する所定の演算処理により前記試験電流の実効値を求める試験電流抽出手段と、
前記抵抗性地絡電流成分の実効値または前記試験電流の実効値が所定の閾値以上のときにその旨を報知する報知手段とを備え、
前記試験電流は、前記基準信号の位相に対して第１の位相β（β＝０を含む）を持つ第１の試験電流成分Ｉ ｔ１ と、前記基準信号の位相に対して前記第１の位相βと異なる第２の位相β＋γ（ただしγ≠０）を持つ第２の試験電流成分Ｉ ｔ２ とが、前記基準信号の周期のＮ倍（ただしＮ≧２）に相当する時間で交互に出力されたものであり、
前記試験電流抽出手段は、前記電流取込手段が取り込んだ１周期分の前記合成電流を理想正弦波および理想余弦波とそれぞれ乗算し、
前記第１の試験電流成分Ｉ ｔ１ を含む前記合成電流ｉ １ に前記理想正弦波および前記理想余弦波を乗算した結果をそれぞれＩ ｃ１ 、Ｉ ｓ１ とし、
前記第２の試験電流成分Ｉ ｔ２ を含む前記合成電流ｉ ２ に前記理想正弦波および前記理想余弦波を乗算した結果をそれぞれＩ ｃ２ 、Ｉ ｓ２ とし、
前記基準信号の周期をＴとするとき、
前記試験電流の実効値Ｉ ｔ ／√２を
により求めることを特徴とする絶縁監視装置の試験装置。 Perform an operation confirmation test of an insulation monitoring device that extracts a resistance ground fault current component from the zero-phase current detected by a zero-phase current sensor magnetically coupled to the ground wire of the measured circuit and monitors the insulation of the measured circuit. It is a test device that is performed in a live state,
A commercial voltage synchronizing means for generating a reference signal synchronized with the commercial voltage of the circuit under test,
A test current control unit that has the same frequency and a constant amplitude as the reference signal and that generates a test current that is phase-modulated every N cycles (where N≧2) ;
Test current applying means for applying the test current to the zero-phase current sensor,
Current capturing means for capturing a combined current of the current caused by the test current and the current caused by the zero-phase current detected by the zero-phase current sensor,
Test current extraction means for obtaining an effective value of the test current by a predetermined calculation process for the combined current,
An effective value of the resistive ground fault current component or an effective value of the test current is provided when not less than a predetermined threshold, and informing means for informing that ,
The test current, a first test current component I t1 with (including beta = 0) a first phase beta with respect to the phase of the reference signal, the first phase relative to said reference signal phase a second test current component I t2 with beta different from the second phase beta + gamma (where gamma ≠ 0) is output alternately in a time corresponding to N times the period of the reference signal (where N ≧ 2) It was
The test current extracting means multiplies the combined current for one cycle captured by the current capturing means by an ideal sine wave and an ideal cosine wave, respectively.
The result of multiplying the ideal sine wave and the ideal cosine wave to the combined current i 1 including the first test current component I t1 and I c1, I s1 respectively,
The result of multiplying the ideal sine wave and the ideal cosine wave to the composite current i 2 including the second test current component I t2 and I c2, I s2 respectively,
When the cycle of the reference signal is T,
The effective value I t /√2 of the test current is
Insulation monitoring device testing equipment characterized by the following .
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