JP2008241668A - Ground fault detector - Google Patents

Ground fault detector Download PDF

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JP2008241668A
JP2008241668A JP2007086845A JP2007086845A JP2008241668A JP 2008241668 A JP2008241668 A JP 2008241668A JP 2007086845 A JP2007086845 A JP 2007086845A JP 2007086845 A JP2007086845 A JP 2007086845A JP 2008241668 A JP2008241668 A JP 2008241668A
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Shinichi Morikawa
真一 森川
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Daihen Corp
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Abstract

<P>PROBLEM TO BE SOLVED: To provide a ground fault detector preventing precision for detecting a ground fault direction from decreasing. <P>SOLUTION: A current detector 5 for detecting each line current and a voltage detector 3 for detecting a reference voltage are provided at appropriate locations in a three-phase distribution line 2. An A/D converter 8 with a reference voltage as input and an A/D converter 10 with a zero-phase current as input are provided. The ground fault detector comprises a ground fault direction determination means 20 comprising: a reference voltage zero-cross point detection processing section 20a1 with a point in time when the output of the A/D converter 8 exceeds a setting value as a reference voltage zero-cross point; a zero-phase current zero-cross point detection processing section 20a3 with a point in time when the output of the A/D converter 10 exceeds a setting value as a zero-phase current zero-cross point; and a phase difference detection determination processing section 20a4 for determining whether a ground fault accident is at a power supply side or a load side to the detection point by obtaining a phase difference from a reference voltage zero-cross point outputted from the reference voltage zero-cross point detection processing section and a zero-phase current zero-cross point outputted from the zero-phase current zero-cross point detection processing section. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

本発明は、３相配電線での地絡事故の方向を検出する地絡検出装置に関するものである。   The present invention relates to a ground fault detection device that detects the direction of a ground fault in a three-phase distribution line.

変電所から引き出される３相配電線の適宜の箇所に各線電流を検出する電流検出器をそれぞれ設けると共に、配電線の線間電圧を検出する電圧検出器を設け、電圧検出器により検出される線間電圧と、電流検出器により検出された線電流から算出された零相電流との位相差を求めることにより、地絡事故が上記検出点に対し、電源側であるか負荷側であるかを判定するようにした地絡検出装置は、例えば、特許文献１に示されている。   A current detector for detecting each line current is provided at an appropriate location of the three-phase distribution line drawn from the substation, and a voltage detector for detecting the line voltage of the distribution line is provided. By determining the phase difference between the voltage and the zero-phase current calculated from the line current detected by the current detector, it is determined whether the ground fault is on the power supply side or the load side with respect to the detection point. A ground fault detection apparatus configured to do so is disclosed in Patent Document 1, for example.

また、共に算出された零相電圧と零相電流との位相差を求めることにより、上記地絡事故の方向判定が行われるものもある。   In some cases, the direction of the ground fault is determined by obtaining the phase difference between the zero-phase voltage and the zero-phase current calculated together.

図３は検出情報をアナログ処理する従来の地絡検出装置を示すブロック図である。この地絡検出装置は、本発明者が従来から実施していたものである。   FIG. 3 is a block diagram showing a conventional ground fault detection apparatus that performs analog processing of detection information. This ground fault detection apparatus has been conventionally implemented by the present inventors.

地絡検出装置４０は図示するように、変電所１から引き出されるＵ相，Ｖ相，Ｗ相の３相配電線２（２ｕ，２ｖ，２ｗ）の適宜の箇所に設けられており、３相配電線２の所定の線間、例えば配電線２ｕ，２ｗの線間電圧を基準電圧Ｖｗｕとして検出する電圧検出器３と、３相配電線の各線電流を検出する電流検出器５（５ｕ，５ｖ，５ｗ）と、零相電流演算回路７と、地絡方向判定手段４０ａと、地絡表示器１１とから構成されている。   As shown in the figure, the ground fault detection device 40 is provided at an appropriate location of the U-phase, V-phase, and W-phase three-phase distribution lines 2 (2u, 2v, 2w) drawn from the substation 1, and the three-phase distribution lines. A voltage detector 3 that detects a line voltage between two predetermined lines, for example, the distribution lines 2u and 2w as a reference voltage Vwu, and a current detector 5 (5u, 5v, and 5w) that detects each line current of the three-phase distribution lines And a zero-phase current calculation circuit 7, a ground fault direction determination means 40 a, and a ground fault indicator 11.

地絡方向判定手段４０ａは、基準電圧方形波生成回路４０a7と、零相電流方形波生成回路４０a8と、位相差検出判定回路４０a9とから構成されている。   The ground fault direction determination means 40a includes a reference voltage square wave generation circuit 40a7, a zero-phase current square wave generation circuit 40a8, and a phase difference detection determination circuit 40a9.

零相電流演算回路７は、電流検出器５により検出される各線電流に基づいて零相電流を算出する。   The zero phase current calculation circuit 7 calculates a zero phase current based on each line current detected by the current detector 5.

基準電圧方形波生成回路４０a7は比較回路からなり、基準電圧が電圧設定値を超えている期間を「Ｈ」レベルとする電圧方形波を生成する。零相電流方形波生成回路４０a8は比較回路からなり、零相電流が電流設定値を超えている期間を「Ｈ」レベルとする電流方形波を生成する。   The reference voltage square wave generation circuit 40a7 is composed of a comparison circuit, and generates a voltage square wave having an “H” level during a period in which the reference voltage exceeds the voltage setting value. The zero-phase current square wave generation circuit 40a8 is composed of a comparison circuit, and generates a current square wave having an “H” level during a period in which the zero-phase current exceeds the current set value.

位相差検出判定回路４０a9は、電圧検出器３により検出される基準電圧と、零相電流演算回路７により算出される零相電流との位相を比較し、零相電流が進み位相または遅れ位相であるかを判定すると共に、その位相差を算出する。この位相差は、電圧方形波の立ち上がり時点と電流方形波の立ち上がり時点との差としている。   The phase difference detection determination circuit 40a9 compares the phase of the reference voltage detected by the voltage detector 3 with the phase of the zero-phase current calculated by the zero-phase current calculation circuit 7, and the zero-phase current is advanced or delayed. It is determined whether it exists, and the phase difference is calculated. This phase difference is the difference between the rising time of the voltage square wave and the rising time of the current square wave.

地絡表示器１１は、判定された進み位相または遅れ位相と、算出された位相差とから、地絡事故が上記検出点に対し、電源側であるか負荷側であるかを表示する。
特開平５−８０１０９号公報 The ground fault indicator 11 displays whether the ground fault is on the power source side or the load side with respect to the detection point from the determined leading phase or lagging phase and the calculated phase difference.
Japanese Patent Laid-Open No. 5-80109

位相差は本来、基準電圧の瞬時値が零レベルをクロスした時点と零相電流の瞬時値が零レベルをクロスした時点との差（真の位相差）であるので、この真の位相差を求めるには、基準電圧方形波生成回路及び零相電流方形波生成回路の各設定値を極力低くすればよい。しかしながら、図３に示す従来の地絡検出装置では、零相電流の電流方形波を生成するための設定値は、零相電流に重畳するノイズ等の影響を避けるために、比較的高くしている。したがって、電流方形波の立ち上がり時点が基準電圧の瞬時値が零レベルをクロスした時点から遅れることになる。この遅れは、零相電流の振幅が大きい地絡事故と、振幅が小さい地絡事故とでは、零相電流の振幅が小さくなる程、その度合いが大きくなる。この遅れが真の位相差に誤差を発生させることになり、地絡方向検出の精度が低下するという問題が生じる。   The phase difference is essentially the difference (true phase difference) between the moment when the instantaneous value of the reference voltage crosses the zero level and the moment when the instantaneous value of the zero-phase current crosses the zero level. In order to obtain it, each set value of the reference voltage square wave generation circuit and the zero-phase current square wave generation circuit may be made as low as possible. However, in the conventional ground fault detection apparatus shown in FIG. 3, the setting value for generating the current square wave of the zero phase current is set to be relatively high in order to avoid the influence of noise or the like superimposed on the zero phase current. Yes. Therefore, the rising time of the current square wave is delayed from the time when the instantaneous value of the reference voltage crosses the zero level. The degree of this delay increases with a decrease in the zero-phase current amplitude in a ground fault with a large zero-phase current amplitude and a ground fault with a small amplitude. This delay causes an error in the true phase difference, resulting in a problem that the accuracy of detecting the ground fault direction is lowered.

一方、零相電圧と零相電流との位相差を求めることによる地絡検出装置では、零相電圧の電圧波形を生成するための設定値は、零相電圧に重畳するノイズ等の影響を避けるために、零相電流の場合と同様に比較的高くしている。したがって、電圧方形波の立ち上がり時点が零相電圧の瞬時値が零レベルをクロスした時点から遅れることになる。この遅れは、零相電圧の振幅が大きい地絡事故と、振幅が小さい地絡事故とでは、零相電圧の振幅が小さくなる程、その度合いが大きくなる。この零相電圧の遅れと零相電流の遅れとが加算されて真の位相差にさらに大きな誤差を発生させることになり、地絡方向検出の精度がさらに低下するという問題が生じる。   On the other hand, in the ground fault detection device by obtaining the phase difference between the zero-phase voltage and the zero-phase current, the setting value for generating the voltage waveform of the zero-phase voltage avoids the influence of noise or the like superimposed on the zero-phase voltage. Therefore, it is made relatively high as in the case of the zero-phase current. Therefore, the rising time of the voltage square wave is delayed from the time when the instantaneous value of the zero-phase voltage crosses the zero level. The degree of this delay increases with a decrease in the amplitude of the zero phase voltage in a ground fault with a large amplitude of the zero phase voltage and a ground fault with a small amplitude. The delay of the zero-phase voltage and the delay of the zero-phase current are added to generate a larger error in the true phase difference, resulting in a problem that the accuracy in detecting the ground fault direction is further lowered.

本発明の目的は、地絡方向検出の精度の低下を防止した地絡検出装置を提供することにある。   The objective of this invention is providing the ground fault detection apparatus which prevented the fall of the precision of ground fault direction detection.

第１の発明は、変電所から引き出される３相配電線の適宜の箇所に、各線電流を検出する電流検出器を設けると共に、配電線の所定の線間電圧を基準電圧として検出する電圧検出器を設け、電圧検出器により検出される基準電圧と、電流検出器により検出された線電流から算出される零相電流との位相差を求めることにより、地絡事故が検出点に対し、電源側であるか負荷側であるかを判定するようにした地絡検出装置を対象とし、基準電圧を入力としてデジタル値を出力する基準電圧用Ａ／Ｄ変換器と、零相電流を入力としてデジタル値を出力する零相電流用Ａ／Ｄ変換器と、基準電圧用Ａ／Ｄ変換器から出力されるデジタル値が設定値を越えた時点を基準電圧零クロス点とする基準電圧零クロス点検出処理部と、零相電流用Ａ／Ｄ変換器から出力されるデジタル値が設定値を越えた時点を零相電流零クロス点とする零相電流零クロス点検出処理部と、基準電圧零クロス点検出処理部から出力される基準電圧零クロス点と、零相電流零クロス点検出処理部から出力される零相電流零クロス点とから位相差を求めることにより、地絡事故が検出点に対し、電源側であるか負荷側であるかを判定する位相差検出判定処理部とからなる地絡方向判定手段を備えたものである。   The first invention is provided with a current detector for detecting each line current at an appropriate position of the three-phase distribution line drawn from the substation, and a voltage detector for detecting a predetermined line voltage of the distribution line as a reference voltage. By providing the phase difference between the reference voltage detected by the voltage detector and the zero-phase current calculated from the line current detected by the current detector, a ground fault can occur on the power source side with respect to the detection point. Targeting a ground fault detection device that determines whether it is on the load side, a reference voltage A / D converter that outputs a digital value with a reference voltage as an input, and a digital value with a zero-phase current as an input A zero-phase current A / D converter for output and a reference voltage zero-cross point detection processing unit in which a time when a digital value output from the reference voltage A / D converter exceeds a set value is set as a reference voltage zero-cross point A / D converter for zero-phase current Zero-phase current zero-crossing point detection processing unit that sets the zero-phase current zero-crossing point when the digital value output from the controller exceeds the set value, and the reference voltage zero-crossing point output from the reference voltage zero-crossing point detection processing unit And the phase difference from the zero-phase current zero-cross point output from the zero-phase current zero-cross point detection processing unit to determine whether the ground fault is on the power supply side or the load side with respect to the detection point. A ground fault direction determination unit including a phase difference detection determination processing unit for determination is provided.

第２の発明は、変電所から引き出される３相配電線の適宜の箇所に、各線電流を検出する電流検出器を設けると共に、配電線の各相電圧を検出する電圧検出器を設け、電圧検出器により検出される相電圧から算出される零相電圧と、電流検出器により検出された線電流から算出される零相電流との位相差を求めることにより、地絡事故が検出点に対し、電源側であるか負荷側であるかを判定するようにした地絡検出装置を対象とし、零相電圧を入力としてデジタル値を出力する零相電圧用Ａ／Ｄ変換器と、零相電圧用Ａ／Ｄ変換器から出力されるデジタル値が設定値を越えた時点を零相電圧零クロス点とする零相電圧零クロス点検出回路と、零相電流を入力としてデジタル値を出力する零相電流用Ａ／Ｄ変換器と、零相電流用Ａ／Ｄ変換器から出力されるデジタル値が設定値を越えた時点を零相電流零クロス点とする零相電流零クロス点検出回路と、零相電圧零クロス点検出回路から出力される零相電圧位相検出点と、零相電流零クロス点検出回路から出力される零相電流零クロス点とから位相差を求めることにより、地絡事故が上記検出点に対し、電源側であるか負荷側であるかを判定する位相差検出判定回路とを備えたものである。   According to a second aspect of the present invention, a current detector for detecting each line current is provided at an appropriate location of the three-phase distribution line drawn from the substation, and a voltage detector for detecting each phase voltage of the distribution line is provided. By calculating the phase difference between the zero-phase voltage calculated from the phase voltage detected by the current detector and the zero-phase current calculated from the line current detected by the current detector, A zero-phase voltage A / D converter that outputs a digital value with a zero-phase voltage as an input, and a zero-phase voltage A Zero-phase voltage zero-crossing point detection circuit that sets the zero-phase voltage zero-crossing point when the digital value output from the D / D converter exceeds the set value, and zero-phase current that outputs the digital value with the zero-phase current input A / D converter and zero-phase current A / D converter A zero-phase current zero-cross point detection circuit that sets the zero-phase current zero-cross point when the output digital value exceeds the set value, and a zero-phase voltage phase detection point that is output from the zero-phase voltage zero-cross point detection circuit, By determining the phase difference from the zero-phase current zero-cross point output from the zero-phase current zero-cross point detection circuit, it is determined whether the ground fault is on the power supply side or the load side with respect to the detection point And a phase difference detection determination circuit.

以上のように、第１の発明によれば、配電線の所定の線間電圧と零相電流との位相差を求めることにより、地絡事故の方向判定する地絡検出装置に対し、基準電圧のデジタル値が設定値を越えた時点は、基準電圧の瞬時値が零レベルをクロスした時点と同じになり、また、零相電流のデジタル値が設定値を越えた時点は、零相電流の瞬時値が零レベルをクロスした時点と同じになる。したがって、零相電流零クロス点は、零相電流の振幅の大小に関係なくなるので、常に真の位相差が求められ、地絡方向検出精度の向上を図ることができる。   As described above, according to the first invention, the ground voltage detection device for determining the direction of the ground fault is obtained by obtaining the phase difference between the predetermined line voltage of the distribution line and the zero-phase current. When the digital value exceeds the set value, it is the same as when the instantaneous value of the reference voltage crosses the zero level, and when the digital value of the zero-phase current exceeds the set value, the zero-phase current It is the same as when the instantaneous value crosses the zero level. Therefore, the zero-phase current zero cross point is not related to the magnitude of the amplitude of the zero-phase current, so that a true phase difference is always obtained, and the ground fault direction detection accuracy can be improved.

第２の発明によれば、配電線の零相電圧と零相電流との位相差を求めることにより、地絡事故の方向判定する地絡検出装置に対し、零相電圧のデジタル値が設定値を越えた時点は、零相電圧の瞬時値が零レベルをクロスした時点と同じになり、また、零相電流のデジタル値が設定値を越えた時点は、零相電流の瞬時値が零レベルをクロスした時点と同じになる。したがって、零相電圧零クロス点及び零相電流零クロス点は、零相電圧及び零相電流のそれぞれ振幅の大小に関係なくなるので、常に真の位相差が求められ、地絡方向検出精度の向上を図ることができる。   According to the second invention, the digital value of the zero-phase voltage is set to the set value for the ground fault detection device for determining the direction of the ground fault by calculating the phase difference between the zero-phase voltage and the zero-phase current of the distribution line. The moment when the instantaneous value of the zero-phase voltage crosses the zero level is the same as the moment when the zero-phase voltage exceeds the set value. It will be the same as when crossed. Therefore, the zero-phase voltage zero-cross point and the zero-phase current zero-cross point are irrelevant to the magnitudes of the amplitudes of the zero-phase voltage and the zero-phase current. Therefore, a true phase difference is always obtained, and the ground fault direction detection accuracy is improved. Can be achieved.

図１は本発明に係る地絡検出装置の第１の実施形態を示すブロック図である。地絡検出装置２０は図３と同様に、変電所１から引き出される３相配電線２に設けられており、図示するように、例えば配電線２ｕ，２ｗの線間電圧を基準電圧Ｖｗｕとして検出する線間電圧検出器３と、各線電流を検出する電流検出器５（５ｕ，５ｖ，５ｗ）と、零相電流演算回路７と、基準電圧用Ａ／Ｄ変換器８、零相電流用Ａ／Ｄ変換器１０と、地絡方向判定手段２０ａと、地絡表示器１１とから構成されている。   FIG. 1 is a block diagram showing a first embodiment of a ground fault detection apparatus according to the present invention. Similarly to FIG. 3, the ground fault detection device 20 is provided in the three-phase distribution line 2 drawn from the substation 1, and detects, for example, the line voltage of the distribution lines 2u and 2w as the reference voltage Vwu as shown in the figure. Line voltage detector 3, current detector 5 (5u, 5v, 5w) for detecting each line current, zero phase current calculation circuit 7, A / D converter for reference voltage 8, A / D for zero phase current It comprises a D converter 10, a ground fault direction determination means 20 a, and a ground fault indicator 11.

地絡方向判定手段２０ａは、基準電圧零クロス点検出処理部２０a1と、零相電流零クロス点検出処理部２０a3と、位相差検出判定処理部２０a4との各機能を有するＣＰＵ等から構成されている。   The ground fault direction determination means 20a is composed of a CPU having functions of a reference voltage zero cross point detection processing unit 20a1, a zero phase current zero cross point detection processing unit 20a3, and a phase difference detection determination processing unit 20a4. Yes.

零相電流演算回路７は、電流検出器５により検出される各線電流に基づいて零相電流を算出するが、零相電流は電圧に変換されて出力される。   The zero-phase current calculation circuit 7 calculates a zero-phase current based on each line current detected by the current detector 5, and the zero-phase current is converted into a voltage and output.

基準電圧用Ａ／Ｄ変換器８は、電圧検出器３から出力される基準電圧を入力としてデジタル値を出力する。零相電流用Ａ／Ｄ変換器１０は、零相電流演算回路７から出力される零相電流を入力としてデジタル値を出力する。 The reference voltage A / D converter 8 receives the reference voltage output from the voltage detector 3 and outputs a digital value. The zero-phase current A / D converter 10 receives the zero-phase current output from the zero-phase current calculation circuit 7 and outputs a digital value.

基準電圧零クロス点検出処理部２０a1は、基準電圧用Ａ／Ｄ変換器８から出力される基準電圧のデジタル値が基準電圧設定値を越えた時点を基準電圧零クロス点検出情報として出力する。零相電流零クロス点検出処理部２０a3は、零相電流用Ａ／Ｄ変換器１０から出力される零相電流のデジタル値が零相電流設定値を越えた時点を零相電流零クロス点検出情報として出力する。基準電圧用Ａ／Ｄ変換器８及び零相電流用Ａ／Ｄ変換器１０が、例えば１２ビット、バイナリコード変換するものであれば、入力範囲を１／４０９６（２の１２乗分の１）刻みでＡＤ変換される。すなわち、変換値０〜４０９５に変換されるので、上記の各設定値を０〜４０９５の中間値２０４８とすれば、基準電圧のデジタル値が設定値を越えた時点は、基準電圧の瞬時値が零レベルをクロスした時点と同じになり、この時点を基準電圧零クロス点検出情報とし、また、零相電流のデジタル値が設定値を越えた時点は、零相電流の瞬時値が零レベルをクロスした時点と同じになり、この時点を零相電流零クロス点検出情報とする。したがって、零相電流零クロス点は、零相電流の振幅の大小に関係なくなるので、常に真の位相差が求められる。   The reference voltage zero cross point detection processing unit 20a1 outputs the time when the digital value of the reference voltage output from the reference voltage A / D converter 8 exceeds the reference voltage set value as reference voltage zero cross point detection information. The zero-phase current zero-cross point detection processing unit 20a3 detects the zero-phase current zero-cross point when the digital value of the zero-phase current output from the zero-phase current A / D converter 10 exceeds the zero-phase current set value. Output as information. If the reference voltage A / D converter 8 and the zero-phase current A / D converter 10 are, for example, 12-bit binary code converters, the input range is 1/44096 (one-twelfth power of 12). AD conversion is performed in increments. That is, since the converted values are converted to 0 to 4095, if each of the set values is set to an intermediate value 2048 of 0 to 4095, the instantaneous value of the reference voltage is obtained when the digital value of the reference voltage exceeds the set value. This is the same as when the zero level is crossed, and this point is used as reference voltage zero-crossing point detection information.When the digital value of the zero-phase current exceeds the set value, the instantaneous value of the zero-phase current is zero. It becomes the same as the time of crossing, and this time is set as zero phase current zero cross point detection information. Therefore, the zero phase current zero cross point is not related to the magnitude of the amplitude of the zero phase current, so that a true phase difference is always obtained.

位相差検出判定処理部２０a4は、基準電圧零クロス点検出情報が入力された時点でリセットされると共にカウントを開始し、零相電流零クロス点検出情報が入力された時点でカウントを終了する。このときのカウント値が基準電圧と零相電流との位相差となる。   The phase difference detection determination processing unit 20a4 is reset when the reference voltage zero cross point detection information is input and starts counting, and ends the count when the zero phase current zero cross point detection information is input. The count value at this time is the phase difference between the reference voltage and the zero-phase current.

図２は本発明に係る地絡検出装置の第２の実施形態を示すブロック図である。地絡検出装置３０は図３と同様に、変電所１から引き出される３相配電線２に設けられており、図示するように配電線２（２ｕ，２ｖ，２ｗ）の相電圧をそれぞれ検出する相電圧検出器４と、各線電流を検出する電流検出器５（５ｕ，５ｖ，５ｗ）と、零相電圧演算回路６と、零相電流演算回路７と、零相電圧用Ａ／Ｄ変換器９、零相電流用Ａ／Ｄ変換器１０と、地絡方向判定手段３０ａと、地絡表示器１１とから構成されている。   FIG. 2 is a block diagram showing a second embodiment of the ground fault detection apparatus according to the present invention. Similarly to FIG. 3, the ground fault detection device 30 is provided in the three-phase distribution line 2 drawn from the substation 1, and as shown in the figure, the phase voltage of the distribution line 2 (2u, 2v, 2w) is detected. Voltage detector 4, current detector 5 (5u, 5v, 5w) for detecting each line current, zero phase voltage calculation circuit 6, zero phase current calculation circuit 7, and zero phase voltage A / D converter 9 The zero-phase current A / D converter 10, the ground fault direction determining means 30 a, and the ground fault indicator 11 are configured.

地絡方向判定手段３０ａは、零相電圧零クロス点検出処理部３０a2と、零相電流零クロス点検出処理部３０a3と、位相差検出判定処理部３０a4との各機能をを有するＣＰＵ等から構成されている。   The ground fault direction determination means 30a includes a CPU having functions of a zero phase voltage zero cross point detection processing unit 30a2, a zero phase current zero cross point detection processing unit 30a3, and a phase difference detection determination processing unit 30a4. Has been.

零相電圧演算回路６は、電圧検出器４により検出される各相電圧に基づいて零相電圧を算出する。零相電流演算回路７は、電流検出器５により検出される各線電流に基づいて零相電流を算出するが、零相電流は電圧に変換されて出力される。   The zero phase voltage calculation circuit 6 calculates a zero phase voltage based on each phase voltage detected by the voltage detector 4. The zero-phase current calculation circuit 7 calculates a zero-phase current based on each line current detected by the current detector 5, and the zero-phase current is converted into a voltage and output.

零相電圧用Ａ／Ｄ変換器９は、零相電圧演算回路６から出力される零相電圧を入力としてデジタル値を出力する。零相電流用Ａ／Ｄ変換器１０は、零相電流演算回路７から出力される零相電流を入力としてデジタル値を出力する。 The zero-phase voltage A / D converter 9 receives the zero-phase voltage output from the zero-phase voltage calculation circuit 6 and outputs a digital value. The zero-phase current A / D converter 10 receives the zero-phase current output from the zero-phase current calculation circuit 7 and outputs a digital value.

零相電圧零クロス点検出処理部３０a2は、零相電圧用Ａ／Ｄ変換器９から出力される零相電圧のデジタル値が零相電圧設定値を越えた時点を零相電圧零クロス点検出情報として出力する。零相電流零クロス点検出処理部３０a3は、零相電流用Ａ／Ｄ変換器１０から出力される零相電流のデジタル値が零相電流設定値を越えた時点を零相電流零クロス点検出情報として出力する。零相電圧用Ａ／Ｄ変換器９及び零相電流用Ａ／Ｄ変換器１０が、例えば１２ビット、バイナリコード変換するものであれば、入力範囲を１／４０９６（２の１２乗分の１）刻みでＡＤ変換される。すなわち、変換値０〜４０９５に変換されるので、上記の各設定値を０〜４０９５の中間値２０４８とすれば、零相電圧のデジタル値が設定値を越えた時点は、零相電圧の瞬時値が零レベルをクロスした時点と同じになり、この時点を零相電圧零クロス点検出情報とし、また、零相電流のデジタル値が設定値を越えた時点は、零相電流の瞬時値が零レベルをクロスした時点と同じになり、この時点を零相電流零クロス点検出情報とする。したがって、零相電圧零クロス点及び零相電流零クロス点は、零相電圧及び零相電流のそれぞれ振幅の大小に関係なくなるので、常に真の位相差が求められる。   The zero phase voltage zero cross point detection processing unit 30a2 detects the zero phase voltage zero cross point when the digital value of the zero phase voltage output from the zero phase voltage A / D converter 9 exceeds the zero phase voltage set value. Output as information. The zero phase current zero cross point detection processing unit 30a3 detects the zero phase current zero cross point when the digital value of the zero phase current output from the zero phase current A / D converter 10 exceeds the zero phase current set value. Output as information. If the zero-phase voltage A / D converter 9 and the zero-phase current A / D converter 10 perform, for example, 12-bit binary code conversion, the input range is 1/4096 (one-twelfth power of 12). ) AD conversion in steps. That is, since the converted values are converted to 0 to 4095, if each of the above set values is set to an intermediate value 2048 of 0 to 4095, the moment when the digital value of the zero phase voltage exceeds the set value is the instantaneous value of the zero phase voltage. The value is the same as when the zero level is crossed, and this point is used as zero-phase voltage zero-cross point detection information, and when the digital value of the zero-phase current exceeds the set value, the instantaneous value of the zero-phase current is This is the same as the time when the zero level is crossed, and this time is used as the zero-phase current zero-cross point detection information. Therefore, the zero-phase voltage zero-cross point and the zero-phase current zero-cross point are irrelevant to the magnitudes of the amplitudes of the zero-phase voltage and the zero-phase current, so that a true phase difference is always obtained.

位相差検出判定処理部３０a4は、零相電圧零クロス点検出情報が入力された時点でリセットされると共にカウントを開始し、零相電流零クロス点検出情報が入力された時点でカウントを終了する。このときのカウント値が零相電圧と零相電流との位相差となる。   The phase difference detection determination processing unit 30a4 is reset when the zero phase voltage zero cross point detection information is input and starts counting, and ends the count when the zero phase current zero cross point detection information is input. . The count value at this time is the phase difference between the zero-phase voltage and the zero-phase current.

本発明に係る地絡検出装置の第１の実施形態を示すブロック図である。It is a block diagram which shows 1st Embodiment of the ground fault detection apparatus which concerns on this invention. 本発明に係る地絡検出装置の第２の実施形態を示すブロック図である。It is a block diagram which shows 2nd Embodiment of the ground fault detection apparatus which concerns on this invention. 従来の地絡検出装置を示すブロック図である。It is a block diagram which shows the conventional ground fault detection apparatus.

符号の説明Explanation of symbols

１ 変電所
２ ３相配電線
３ 線間電圧検出器
４ 相電圧検出器
５ 電流検出器
８ 基準電圧用Ａ／Ｄ変換器
９ 零相電圧用Ａ／Ｄ変換器
１０ 零相電流用Ａ／Ｄ変換器
２０ 地絡検出装置
２０a1 基準電圧零クロス点検出処理部
２０a3 零相電流零クロス点検出処理部
２０a4 位相差検出判定処理部
２０ａ 地絡方向判定手段
３０ 地絡検出装置
３０a2 零相電圧零クロス点検出処理部
３０a3 零相電流零クロス点検出処理部
３０a4 位相差検出判定処理部 DESCRIPTION OF SYMBOLS 1 Substation 2 3 phase distribution line 3 Line voltage detector 4 Phase voltage detector 5 Current detector 8 A / D converter for reference voltage 9 A / D converter for zero phase voltage 10 A / D conversion for zero phase current 20 Ground fault detection device 20a1 Reference voltage zero cross point detection processing unit 20a3 Zero phase current zero cross point detection processing unit 20a4 Phase difference detection determination processing unit 20a Ground fault direction determination means 30 Ground fault detection device 30a2 Zero phase voltage zero cross inspection Out processing unit 30a3 Zero phase current zero cross point detection processing unit 30a4 Phase difference detection judgment processing unit

Claims (2)

変電所から引き出される３相配電線の適宜の箇所に、各線電流を検出する電流検出器を設けると共に、前記配電線の所定の線間電圧を基準電圧として検出する電圧検出器を設け、前記電圧検出器により検出される前記基準電圧と、前記電流検出器により検出された線電流から算出される零相電流との位相差を求めることにより、地絡事故が検出点に対し、電源側であるか負荷側であるかを判定するようにした地絡検出装置であって、
前記基準電圧を入力としてデジタル値を出力する基準電圧用Ａ／Ｄ変換器と、
前記零相電流を入力としてデジタル値を出力する零相電流用Ａ／Ｄ変換器と、
前記基準電圧用Ａ／Ｄ変換器から出力されるデジタル値が設定値を越えた時点を基準電圧零クロス点とする基準電圧零クロス点検出処理部と、
前記零相電流用Ａ／Ｄ変換器から出力されるデジタル値が設定値を越えた時点を零相電流零クロス点とする零相電流零クロス点検出処理部と、
前記基準電圧零クロス点検出処理部から出力される基準電圧零クロス点と、前記零相電流零クロス点検出処理部から出力される零相電流零クロス点とから位相差を求めることにより、地絡事故が検出点に対し、電源側であるか負荷側であるかを判定する位相差検出判定処理部とからなる地絡方向判定手段を備えた地絡検出装置。 A current detector for detecting each line current is provided at an appropriate location of the three-phase distribution line drawn from the substation, and a voltage detector for detecting a predetermined line voltage of the distribution line as a reference voltage is provided to detect the voltage. Whether the ground fault is on the power supply side with respect to the detection point by determining the phase difference between the reference voltage detected by the detector and the zero-phase current calculated from the line current detected by the current detector A ground fault detection device for determining whether it is on the load side,
A reference voltage A / D converter that outputs a digital value with the reference voltage as an input;
A zero-phase current A / D converter that outputs the digital value with the zero-phase current as an input;
A reference voltage zero cross point detection processing unit which sets a time when a digital value output from the reference voltage A / D converter exceeds a set value as a reference voltage zero cross point;
A zero-phase current zero-cross point detection processing unit in which a time point when a digital value output from the zero-phase current A / D converter exceeds a set value is a zero-phase current zero-cross point;
By calculating the phase difference from the reference voltage zero cross point output from the reference voltage zero cross point detection processing unit and the zero phase current zero cross point output from the zero phase current zero cross point detection processing unit, A ground fault detection device comprising a ground fault direction determination means comprising a phase difference detection determination processing unit that determines whether a fault is on the power supply side or the load side with respect to a detection point. 変電所から引き出される３相配電線の適宜の箇所に、各線電流を検出する電流検出器を設けると共に、前記配電線の各相電圧を検出する電圧検出器を設け、前記電圧検出器により検出される相電圧から算出される零相電圧と、前記電流検出器により検出された線電流から算出される零相電流との位相差を求めることにより、地絡事故が検出点に対し、電源側であるか負荷側であるかを判定するようにした地絡検出装置であって、
前記零相電圧を入力としてデジタル値を出力する零相電圧用Ａ／Ｄ変換器と、
前記零相電圧用Ａ／Ｄ変換器から出力されるデジタル値が設定値を越えた時点を零相電圧零クロス点とする零相電圧零クロス点検出回路と、
前記零相電流を入力としてデジタル値を出力する零相電流用Ａ／Ｄ変換器と、
前記零相電流用Ａ／Ｄ変換器から出力されるデジタル値が設定値を越えた時点を零相電流零クロス点とする零相電流零クロス点検出回路と、
前記零相電圧零クロス点検出回路から出力される零相電圧位相検出点と、前記零相電流零クロス点検出回路から出力される零相電流零クロス点とから位相差を求めることにより、地絡事故が上記検出点に対し、電源側であるか負荷側であるかを判定する位相差検出判定回路とを備えた地絡検出装置。 A current detector for detecting each line current is provided at an appropriate position of the three-phase distribution line drawn from the substation, and a voltage detector for detecting each phase voltage of the distribution line is provided and detected by the voltage detector. By determining the phase difference between the zero-phase voltage calculated from the phase voltage and the zero-phase current calculated from the line current detected by the current detector, the ground fault is on the power supply side with respect to the detection point. A ground fault detection device for determining whether the load is on the load side,
A zero-phase voltage A / D converter that outputs a digital value with the zero-phase voltage as an input;
A zero-phase voltage zero-crossing point detection circuit having a zero-phase voltage zero-crossing point when the digital value output from the zero-phase voltage A / D converter exceeds a set value;
A zero-phase current A / D converter that outputs the digital value with the zero-phase current as an input;
A zero-phase current zero-crossing point detection circuit in which a time point when the digital value output from the zero-phase current A / D converter exceeds a set value is a zero-phase current zero-crossing point;
By calculating the phase difference from the zero phase voltage phase detection point output from the zero phase voltage zero cross point detection circuit and the zero phase current zero cross point output from the zero phase current zero cross point detection circuit, A ground fault detection apparatus comprising: a phase difference detection determination circuit that determines whether a fault is on the power supply side or the load side with respect to the detection point.
JP2007086845A 2007-03-29 2007-03-29 Ground fault detector Pending JP2008241668A (en)

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Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR101008416B1 (en) 2008-10-28 2011-01-14 한국전력공사 Over current relay protection device for preventing mal-operation by reverse power and the driving method thereof
CN103135034A (en) * 2013-02-04 2013-06-05 清华大学 Extract method of high-impedance-grounded fault waveform distortion features
CN103257302A (en) * 2013-05-13 2013-08-21 清华大学 Method for detecting high impedance grounding fault based on fault resistance nonlinear identification
CN104076249A (en) * 2014-07-15 2014-10-01 国家电网公司 Three-phase three-winding transformer one-phase ground fault coverage diagnostic method
CN104569729A (en) * 2015-01-29 2015-04-29 深圳市科陆电子科技股份有限公司 Fault indicator based power distribution network single-phase earth fault detection method and fault indicator based power distribution network single-phase earth fault detection system
CN107680367A (en) * 2017-09-28 2018-02-09 南京新联能源技术有限责任公司 A kind of bandwidth carrier communication module with taiwan area fault diagnosis functions
CN112924815A (en) * 2021-01-29 2021-06-08 西南交通大学 Fault distance measurement calculation method for AT power supply electrified railway

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6466566A (en) * 1987-09-07 1989-03-13 Hioki Electric Works Phase difference measurement
JPH09212340A (en) * 1996-02-01 1997-08-15 Toyo Commun Equip Co Ltd Trigonometric function calculating circuit
JPH11308758A (en) * 1998-04-21 1999-11-05 Toko Electric Co Ltd Grounding detector

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6466566A (en) * 1987-09-07 1989-03-13 Hioki Electric Works Phase difference measurement
JPH09212340A (en) * 1996-02-01 1997-08-15 Toyo Commun Equip Co Ltd Trigonometric function calculating circuit
JPH11308758A (en) * 1998-04-21 1999-11-05 Toko Electric Co Ltd Grounding detector

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR101008416B1 (en) 2008-10-28 2011-01-14 한국전력공사 Over current relay protection device for preventing mal-operation by reverse power and the driving method thereof
CN103135034A (en) * 2013-02-04 2013-06-05 清华大学 Extract method of high-impedance-grounded fault waveform distortion features
CN103257302A (en) * 2013-05-13 2013-08-21 清华大学 Method for detecting high impedance grounding fault based on fault resistance nonlinear identification
CN104076249A (en) * 2014-07-15 2014-10-01 国家电网公司 Three-phase three-winding transformer one-phase ground fault coverage diagnostic method
CN104569729A (en) * 2015-01-29 2015-04-29 深圳市科陆电子科技股份有限公司 Fault indicator based power distribution network single-phase earth fault detection method and fault indicator based power distribution network single-phase earth fault detection system
CN107680367A (en) * 2017-09-28 2018-02-09 南京新联能源技术有限责任公司 A kind of bandwidth carrier communication module with taiwan area fault diagnosis functions
CN107680367B (en) * 2017-09-28 2020-04-21 南京新联能源技术有限责任公司 Broadband carrier communication module with transformer area fault diagnosis function
CN112924815A (en) * 2021-01-29 2021-06-08 西南交通大学 Fault distance measurement calculation method for AT power supply electrified railway
CN112924815B (en) * 2021-01-29 2022-02-08 西南交通大学 Fault distance measurement calculation method for AT power supply electrified railway

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