JP2004132937A

JP2004132937A - Abnormality detecting method for voltage detector

Info

Publication number: JP2004132937A
Application number: JP2002300361A
Authority: JP
Inventors: Hiroaki Tamura; 田村　浩明
Original assignee: Fuji Electric Systems Co Ltd
Current assignee: Fuji Electric Co Ltd
Priority date: 2002-10-15
Filing date: 2002-10-15
Publication date: 2004-04-30

Abstract

<P>PROBLEM TO BE SOLVED: To quickly detect a voltage detector indicating an abnormal voltage from a logical operation of a plurality of the voltage detectors equipped in an electric system. <P>SOLUTION: A discrimination value which is a value exceeding the differential value between any two voltages of correct voltage detectors equipped in the electric system is established for all combination of detectors . For the all combination of two voltage detectors selected from among all detectors, the absolute value of the differential voltage is compared with the discrimination voltage. If the absolute value of the differential voltage is greater than the discrimination value, a logical signal H is output, if it is smaller, a logical sign L is output from a difference comparison circuit. A logical product for all of the combination of two voltage detectors including a specific voltage detector is calculated. From the result of the calculation of the logical product, the abnormality of the specific voltage detector is determined. <P>COPYRIGHT: (C)2004,JPO

Description

【０００１】
【発明の属する技術分野】
この発明は、共通の電気回路に設置している複数の電圧検出器の相互比較から異常を検出する電圧検出器の異常検出方法に関する。
【０００２】
【従来の技術】
電気系統の各部の電圧を監視するために、それぞれの地点に電圧検出器を設置することは、一般的に行われている。
【０００３】
図３は電気系統に複数の電圧検出器を備えている場合を示した回路図である。この図３において、商用電源７からの交流電力は、整流器８で直流電力に変換される。高速度遮断器４を経たこの直流電力は、接触器７１を介してインバータ１０１へ供給されるが、接触器７２を介してインバータ１０２へも供給される構成であるが、インバータ１０１の電源側にはリアクトル８１とコンデンサ９１が設置されており、インバータ１０２の電源側にもリアクトル８２とコンデンサ９２が設置されていて、これら両コンデンサ９１，９２を充電するための充電抵抗６と、充電抵抗６を短絡する短絡スイッチ５を備えている。また整流器８の直流出力側にには電圧検出器１が、コンデンサ９１には電圧検出器２が、コンデンサ９２には電圧検出器３がそれぞれ並列に接続されていて、それぞれの箇所の電圧を検出している。
【０００４】
インバータ１０１と１０２を始動するにあたっては、先ず電圧検出器１で整流器８が直流電力を供給できる状態であることを検出する。そこで短絡スイッチ５が開の状態のときに高速度遮断器４を閉路し、次いで接触器７１と接触器７２を閉路し、充電抵抗６を介してコンデンサ９１と９２の充電を開始するが、適切な時間が経過すれば短絡スイッチ５を閉路し、コンデンサ９１と９２の充電を完了させる。コンデンサ９１と９２の充電が完了すれば、インバータ１０１と１０２の入力電圧が確立するから運転を開始できる。
【０００５】
図３に図示の回路で、高速度遮断器４と短絡スイッチ５と接触器７１と接触器７２のすべてが閉路している状態では、３つの電圧検出器１，２，３はほぼ同じ値を示すはずであるが、もしもその中の１つが低い電圧値を出力すると、従来ならば直流回路電圧が低下する異常が発生したと判断して、回路を停止にする。
【０００６】
【発明が解決しようとする課題】
電圧検出器が過電圧や不足電圧などの異常電圧を出力して回路を停止させる故障として電圧検出器の故障がある。これは電圧検出器への入力電圧が正常であるにもかかわらず検出器が異常電圧を出力して回路をトリップさせるのであるが、このように回路を停止させるような検出器の故障は、停止の原因を調査する過程で発見できるし、その不具合は除去できる。また、回路電圧が過電圧になった場合は、勿論電圧検出器がこの異常電圧を検出して回路をトリップさせるし、停電は商用電源が復電したことで回路のリセット、あるいは自動再起動により復旧できる。
【０００７】
しかしながら、電圧検出器が故障しているにもかかわらず、その検出する異常値があまり大きな値でない場合は、例えば回路がトリップするような故障に至ることも無いので、当該電圧検出器が故障であることが認識できない。すなわち、検出器が異常であるとの認識がないから、実際は正しくないのに、この検出値は正しいと考えている。この正しくない検出値を使って回路やシステムを制御することになるので、制御が不安定になるなどの不具合を生じる恐れがある。
【０００８】
そこでこの発明の目的は、電気系統に設置している複数の電圧検出器の検出値を基にして論理演算することにより、異常値を呈する電圧検出器を素早く検出できるようにすることにある。
【０００９】
【課題を解決するための手段】
前記の目的を達成するために、この発明の電圧検出器の異常検出方法は、
電気系統に設置している各電圧検出器が健全なときの任意の２つの電圧検出器間に現れる検出電圧の差を越える値を判別値とし、前記各電圧検出器から２つの電圧検出器を選択する組み合わせをすべての場合について定め、２つの電圧検出器の検出電圧の差の絶対値と前記判別値との大小関係の比較を２つの電圧検出器を選択するすべての組み合わせについて行い、差電圧絶対値が前記判別値よりも大となる２つの電圧検出器の組み合わせのすべてに共通している電圧検出器を異常と判定する。
【００１０】
または、電気系統に設置している各電圧検出器が健全なときの任意の２つの電圧検出器間に現れる検出電圧の差を越える値を判別値とし、前記各電圧検出器から２つの電圧検出器を選択する組み合わせをすべての場合について定め、２つの電圧検出器を選択するすべての組み合わせについて、両電圧検出器の検出電圧の差の絶対値と前記判別値との大小関係の比較を行い、この大小関係の比較して差電圧絶対値が前記判別値よりも大のときは論理Ｈ信号を出力させ、小のときは論理Ｌ信号を出力させ、特定の電圧検出器が含まれている２つの電圧検出器の組み合わせのすべてについての前記論理信号の論理積を求め、この論理積演算結果から当該特定電圧検出器の異常の有無を判定する。
【００１１】
【発明の実施の形態】
既述の図３に図示のように、１つの電気系統に３つの電圧検出器１〜３が設置されている場合を例にして、請求項１の発明を説明する。
【００１２】
高速度遮断器４と短絡スイッチ５と接触器７１と接触器７２がすべて閉路していて電気系統が全部つながっている状態で、電圧検出器１の検出値をＶ_ａ，電圧検出器２の検出値をＶ_ｂ，電圧検出器３の検出値をＶ_ｃとする。これら３つの電圧検出器のうちの２つを選ぶ組み合わせは３通りであり、この３通りについて、一方の電圧検出器の検出値と他方の電圧検出器の検出値との差の絶対値を演算しすると、下記の数式１，数式２，数式３が得られる。
【００１３】
【数１】

【００１４】
【数２】

【００１５】
【数３】

電圧検出器を設置している地点間には線路の電圧降下があるから、各電圧検出器の検出値には差異がある。そこで各検出値の差異の最大値を上回る判定値Ｖ_ＲＥを設定し、この判定値Ｖ_ＲＥと差電圧絶対値（数式１乃至数式３の演算）とを比較し、差電圧絶対値のほうが小さければ正常であるが、差電圧絶対値のほうが大きければ、そのときの２つの電圧検出器のどちらか一方が異常である。よって差電圧絶対値のほうが大きい組み合わせのすべてに共通の電圧検出器を異常と判定する。
【００１６】
例えば電圧検出器１が故障してその検出値がＶ_ａ＝０になったとすると、数式１からは、Ｘの絶対値＞Ｖ_ＲＥとなって異常の判定を得る。数式２からは、Ｙの絶対値＜Ｖ_ＲＥとなって正常と判定されるが、数式３からは、Ｚの絶対値＞Ｖ_ＲＥとなって異常の判定を得る。このとき異常判定の基となる計算は、Ｖ_ａ−Ｖ_ｂとＶ_ｃ−Ｖ_ａの２つであり、この両者に共通するのはＶ_ａである。すなわちＶ_ａが異常値を呈するのが原因で、これは電圧検出器１が故障したためと判定できる。
【００１７】
図１は電圧検出器が３つのときの本発明の実施例を表した論理回路図であって、請求項２の発明に対応する。この図１において、論理積素子１０は高速度遮断器４と短絡スイッチ５と接触器７１と接触器７２の開閉状態を入力しており、これらのすべてが閉路のときに論理積素子１０は論理Ｈ信号を出力する。一方で差分比較回路１１は前述したように、Ｖ_ａ−Ｖ_ｂ＝Ｘなる差分演算と、これで得られたＸの絶対値＞Ｖ_ＲＥなる比較演算とを行い、比較の結果がイエスのときは論理Ｈ信号を出力し、ノーのときは論理Ｌ信号を出力する。差分比較回路１２と差分比較回路１３も同様の演算を行って同様の論理信号を出力する。
【００１８】
論理積素子１４は論理積素子１０と差分比較回路１１と差分比較回路１３からの論理信号を入力し、これらのすべてが論理Ｈ信号ならば、オンディレータイマ１７を介して電圧検出器１の故障を表示する。なおオンディレータイマ１７は、過渡現象による誤検出を防ぐためのものである。同様に論理積素子１５は論理積素子１０と差分比較回路１２と差分比較回路１１からの論理信号を入力し、これらのすべてが論理Ｈ信号ならば、オンディレータイマ１８を介して電圧検出器２の故障を表示し、論理積素子１６は論理積素子１０と差分比較回路１３と差分比較回路１２からの論理信号を入力し、これらのすべてが論理Ｈ信号ならば、オンディレータイマ１９を介して電圧検出器３の故障を表示する。
【００１９】
図２は電圧検出器が４つのときの本発明の実施例を表した論理回路図である。４台の電圧検出器２１，２２，２３，２４の検出値をそれぞれＶ_ｄ，Ｖ_ｅ，Ｖ_ｆ，Ｖ_ｇとし、各検出値の差異の最大値を上回る値を判定値Ｖ_ＥＦとすると、４つの電圧検出器２１〜２４の検出値から２つを選ぶ組み合わせは６通りであり、それぞれについて差分の絶対値と判定値との大小関係の比較は、下記の数式４乃至数式９で表される。
【００２０】
【数４】

【００２１】
【数５】

【００２２】
【数６】

【００２３】
【数７】

【００２４】
【数８】

【００２５】
【数９】

図２において、６つの差分比較回路３１〜３６のそれぞれは数式４乃至数式９の比較を行って、その結果がイエスならば論理Ｈ信号を出力し、ノーならば論理Ｌ信号を出力する。４つの論理積素子４１〜４４は、これら差分比較回路３１〜３６の出力信号と検出条件成立信号（例えば各遮断器，接触器の閉路）を入力し、論理演算の結果を４つのオンディレータイマ４６〜４９を介して出力することで、４つの電圧検出器２１〜２４のいずれに故障が発生したかを知ることができる。
【００２６】
例えば電圧検出器２３が故障してその検出値Ｖ_ｆが零になったとすると、差分比較回路３２，３４，３６の出力は論理Ｈ信号となり、残りの差分比較回路３１，３３，３５の出力は論理Ｌ信号となる。その結果、論理積素子４３のみはその入力信号のすべてが論理Ｈ信号となるから、当該論理積素子４３のみが論理Ｈ信号を出力し、電圧検出器２３が故障したことが分かる。
【００２７】
【発明の効果】
電気系統には電圧検出器を設置する。この電圧検出器が故障した場合でも、故障器の検出値が正常値からあまり大きく外れていない場合は、回路がトリップするなどの故障が発生しないから、電圧検出器の故障を認識できなかった。従って当該故障電圧検出器が検出する値を正常値と判断し、これを制御に使用することで制御が不安定になるなどの不具合を生じる恐れがある。
【００２８】
これに対して本発明では、複数の電圧検出器が電気系統に設置されている場合に、各検出値の相互比較で得られる差電圧と判別値とを比較することで、異常値を呈する電圧検出器を素早く検出できるから、故障検出器が出力する非正常検出値を使用することによる各種の不具合（例えば制御の不安定など）を未然に回避できる効果が得られる。
【図面の簡単な説明】
【図１】電圧検出器が３つのときの本発明の実施例を表した論理回路図
【図２】電圧検出器が４つのときの本発明の実施例を表した論理回路図
【図３】電気系統に複数の電圧検出器を備えている場合を示した回路図
【符号の説明】
１〜３　　　　　　　　　　　電圧検出器
４　　　　　　　　　　　　　高速度遮断器
５　　　　　　　　　　　　　短絡スイッチ
６　　　　　　　　　　　　　充電抵抗
８　　　　　　　　　　　　　整流器
１０，１４〜１６，４１〜４４　論理積素子
１１〜１３，３１〜３６　　　　差分比較回路
１７〜１９，４６〜４９　　　　オンディレータイマ
７１，７２　　　　　　　　　　接触器
８１，８２　　　　　　　　　　リアクトル
９１，９２　　　　　　　　　　コンデンサ
１０１，１０２　　　　　　　　　インバータ[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a voltage detector abnormality detection method for detecting an abnormality based on an intercomparison of a plurality of voltage detectors installed in a common electric circuit.
[0002]
[Prior art]
It is common practice to install a voltage detector at each point in order to monitor the voltage of each part of the electrical system.
[0003]
FIG. 3 is a circuit diagram showing a case where a plurality of voltage detectors are provided in the electric system. In FIG. 3, AC power from commercial power supply 7 is converted to DC power by rectifier 8. The DC power that has passed through the high-speed circuit breaker 4 is supplied to the inverter 101 through the contactor 71, but is also supplied to the inverter 102 through the contactor 72. Is provided with a reactor 81 and a capacitor 91, and a reactor 82 and a capacitor 92 are also provided on the power supply side of the inverter 102. The charging resistor 6 for charging the

capacitors

91 and 92 and the charging resistor 6 are connected to each other. A short-circuit switch 5 for short-circuiting is provided. The voltage detector 1 is connected to the DC output side of the rectifier 8, the voltage detector 2 is connected to the capacitor 91, and the voltage detector 3 is connected to the capacitor 92 in parallel. are doing.
[0004]
When starting the

inverters

101 and 102, first, the voltage detector 1 detects that the rectifier 8 can supply DC power. Therefore, when the short-circuit switch 5 is open, the high-speed circuit breaker 4 is closed, then the

contactors

71 and 72 are closed, and charging of the

capacitors

91 and 92 via the charging resistor 6 is started. After an elapse of an appropriate time, the short-circuit switch 5 is closed, and the charging of the

capacitors

91 and 92 is completed. When the charging of the

capacitors

91 and 92 is completed, the operation can be started because the input voltages of the

inverters

101 and 102 are established.
[0005]
In the circuit shown in FIG. 3, when all of the high-speed circuit breaker 4, the short-circuit switch 5, the contactor 71, and the contactor 72 are closed, the three

voltage detectors

1, 2, and 3 have substantially the same value. As shown in the figure, if one of them outputs a low voltage value, it is determined that an abnormality in which the DC circuit voltage is reduced has occurred conventionally, and the circuit is stopped.
[0006]
[Problems to be solved by the invention]
As a failure that causes the voltage detector to output an abnormal voltage such as an overvoltage or an undervoltage and stop the circuit, there is a failure of the voltage detector. This is because the detector outputs abnormal voltage and trips the circuit even though the input voltage to the voltage detector is normal, but such a failure of the detector that stops the circuit stops. Can be discovered in the process of investigating the cause of the problem, and the defect can be eliminated. Also, if the circuit voltage becomes overvoltage, the voltage detector detects this abnormal voltage and trips the circuit, and the power failure is restored by resetting the circuit when the commercial power is restored or by automatic restart. it can.
[0007]
However, if the abnormal value to be detected is not a very large value even though the voltage detector has failed, for example, a failure such as tripping of the circuit does not occur. I do not recognize that there is. That is, since there is no recognition that the detector is abnormal, it is considered that this detection value is correct even though it is not actually correct. Since the circuit or system is controlled using the incorrect detection value, there is a possibility that a problem such as unstable control may occur.
[0008]
SUMMARY OF THE INVENTION It is an object of the present invention to quickly detect a voltage detector exhibiting an abnormal value by performing a logical operation based on detection values of a plurality of voltage detectors installed in an electric system.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, an abnormality detection method for a voltage detector according to the present invention includes:
When each voltage detector installed in the electric system is healthy, a value exceeding a difference between detection voltages appearing between any two voltage detectors is set as a discrimination value, and two voltage detectors are separated from each voltage detector. The combination to be selected is determined for all cases, and the magnitude relationship between the absolute value of the difference between the detection voltages of the two voltage detectors and the discrimination value is compared for all the combinations for selecting the two voltage detectors. A voltage detector common to all combinations of two voltage detectors whose absolute value is larger than the determination value is determined to be abnormal.
[0010]
Alternatively, a value exceeding a difference between detection voltages appearing between any two voltage detectors when each of the voltage detectors installed in the electric system is sound is determined as a determination value, and two voltage detections are performed from each of the voltage detectors. For all combinations of selecting two voltage detectors, the magnitude of the difference between the detected voltages of the two voltage detectors and the magnitude relationship between the discrimination value are compared with each other. When the magnitude relation is compared, if the absolute value of the difference voltage is larger than the discrimination value, a logic H signal is output, and if the absolute value is smaller, a logic L signal is output, and a specific voltage detector is included. The logical product of the logical signals for all the combinations of the two voltage detectors is obtained, and it is determined from the result of the logical product operation whether the specific voltage detector is abnormal.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
The invention of claim 1 will be described by taking as an example a case where three voltage detectors 1 to 3 are installed in one electric system as shown in FIG.
[0012]
Speed breaker 4 and the short-circuit switch 5 and the contactor 71 and the contactor 72 is all are closed in a state in which the electrical system are connected all the detection value V _a of the voltage detector _1, the detection of the voltage detector 2 the value _{V b,} the detection value of the voltage detector 3 and _{V c.} There are three combinations for selecting two of these three voltage detectors, and for these three types, the absolute value of the difference between the detection value of one voltage detector and the detection value of the other voltage detector is calculated. Then, the following Expression 1, Expression 2, and Expression 3 are obtained.
[0013]
(Equation 1)

[0014]
(Equation 2)

[0015]
[Equation 3]

Since there is a voltage drop in the line between the points where the voltage detectors are installed, there are differences in the detection values of the respective voltage detectors. Therefore, a determination value V _RE that exceeds the maximum value of the difference between the respective detection values is set, and this determination value V _RE is compared with the absolute value of the differential voltage (calculation of Expressions 1 to 3). Is normal, but if the absolute value of the difference voltage is larger, one of the two voltage detectors at that time is abnormal. Therefore, it is determined that the voltage detector common to all the combinations having the larger difference voltage absolute value is abnormal.
[0016]
For example, when the voltage detector 1 the detected value by failure to become V _{a =} 0, from equation 1, to obtain a determination of abnormality is the absolute value> V _RE of X. From Expression 2, it is determined that the absolute value of Y < _VRE, and it is determined to be normal. However, from Expression 3, it is determined that the absolute value of Z> _VRE, and the determination of abnormality is obtained. This time calculation underlying the abnormality determination _is two of V a -V _b and _V c -V _a, is _{V a} Common to both. That because the exhibits V _a abnormal value, this can be determined for the voltage detector 1 has failed.
[0017]
FIG. 1 is a logic circuit diagram showing an embodiment of the present invention when there are three voltage detectors, and corresponds to the second aspect of the present invention. In FIG. 1, the AND element 10 inputs the open / close states of the high-speed circuit breaker 4, the short-circuit switch 5, the contactor 71, and the contactor 72. When all of them are closed, the AND element 10 is activated. Outputs H signal. On the other hand the differential comparator circuit 11, as described above, performs a differential operation consisting V a _-V b = _X, and a comparison operation consisting absolute value> V _RE obtained X Now, when the result of the comparison is yes Outputs a logic H signal, and outputs a logic L signal when no. The difference comparison circuit 12 and the difference comparison circuit 13 perform similar operations and output similar logic signals.
[0018]
The logical product element 14 receives the logical signals from the logical product element 10, the difference comparison circuit 11 and the difference comparison circuit 13, and if all of them are logic H signals, the failure of the voltage detector 1 via the on-delay timer 17 Is displayed. The on-delay timer 17 is for preventing erroneous detection due to a transient phenomenon. Similarly, the AND element 15 receives the logic signals from the AND element 10, the difference comparison circuit 12, and the difference comparison circuit 11, and if all of them are logic H signals, the voltage detector 2 is output via the on-delay timer 18. And the AND element 16 receives the logical signals from the AND element 10, the difference comparison circuit 13 and the difference comparison circuit 12, and if all of them are logic H signals, the on-delay timer 19 The failure of the voltage detector 3 is displayed.
[0019]
FIG. 2 is a logic circuit diagram showing an embodiment of the present invention when there are four voltage detectors. Four detection values of the voltage detector 21, 22, respectively _{_{_{V d, V e, V f}}} , and _{V g,} when a value exceeding the maximum value of the difference of the detection value and the determination value _{V EF,} There are six combinations for selecting two from the detection values of the four voltage detectors 21 to 24, and the comparison of the magnitude relationship between the absolute value of the difference and the determination value is expressed by the following Expressions 4 to 9. You.
[0020]
(Equation 4)

[0021]
(Equation 5)

[0022]
(Equation 6)

[0023]
(Equation 7)

[0024]
(Equation 8)

[0025]
(Equation 9)

In FIG. 2, each of the six difference comparison circuits 31 to 36 compares Expressions 4 to 9, and outputs a logic H signal if the result is yes and outputs a logic L signal if no. The four AND elements 41 to 44 receive the output signals of the difference comparison circuits 31 to 36 and the detection condition satisfaction signal (for example, the closing of each circuit breaker and contactor), and output the result of the logical operation to four on-delay timers. By outputting the signals through 46 to 49, it is possible to know which of the four voltage detectors 21 to 24 has failed.
[0026]
For example, if the voltage detector 23 fails and the detection value _Vf becomes zero, the outputs of the

difference comparison circuits

32, 34, and 36 become logical H signals, and the outputs of the remaining difference comparison circuits 31, 33, and 35 become It becomes a logical L signal. As a result, since only the input signal of the AND element 43 becomes a logical H signal, it can be understood that only the logical AND element 43 outputs the logical H signal and the voltage detector 23 has failed.
[0027]
【The invention's effect】
A voltage detector will be installed in the electrical system. Even if the voltage detector fails, if the detected value of the failed device does not deviate significantly from the normal value, no failure such as tripping of the circuit occurs, and the failure of the voltage detector cannot be recognized. Therefore, the value detected by the fault voltage detector is determined to be a normal value, and using the value for control may cause a problem such as unstable control.
[0028]
On the other hand, according to the present invention, when a plurality of voltage detectors are installed in an electric system, a voltage exhibiting an abnormal value is obtained by comparing a difference voltage obtained by mutual comparison of detection values with a discrimination value. Since the detector can be detected quickly, various problems (for example, unstable control) caused by using the abnormal detection value output from the failure detector can be avoided.
[Brief description of the drawings]
FIG. 1 is a logic circuit diagram showing an embodiment of the present invention when there are three voltage detectors. FIG. 2 is a logic circuit diagram showing an embodiment of the present invention when there are four voltage detectors. Circuit diagram showing a case where a plurality of voltage detectors are provided in the electric system [Explanation of reference numerals]
1 to 3 Voltage detector 4 High-speed circuit breaker 5 Short-circuit switch 6 Charging resistor 8 Rectifier 10, 14 to 16, 41 to 44 AND elements 11 to 13, 31 to 36 Difference comparison circuit 17 to 19, 46 to 49 On

delay Timer

71, 72

Contactor

81, 82

Reactor

91, 92

Capacitor

101, 102 Inverter

Claims

From the comparison of the voltage values detected by the voltage detectors separately installed at each of the plurality of points of the electric circuit, in the abnormality detection method of the voltage detector to detect the abnormal voltage detector,
A value exceeding a difference between detection voltages appearing between any two voltage detectors when each of the voltage detectors is sound is determined as a discrimination value,
A combination for selecting two voltage detectors from each of the voltage detectors is determined for all cases,
Comparison of the magnitude relationship between the absolute value of the difference between the detection voltages of the two voltage detectors and the discrimination value is performed for all combinations for selecting the two voltage detectors,
An abnormality detection method for a voltage detector, wherein a voltage detector common to all combinations of two voltage detectors having a difference voltage absolute value larger than the determination value is determined to be abnormal.

From the comparison of the voltage values detected by the voltage detectors separately installed at each of the plurality of points of the electric circuit, in the abnormality detection method of the voltage detector to detect the abnormal voltage detector,
A value exceeding a difference between detection voltages appearing between any two voltage detectors when each of the voltage detectors is sound is determined as a discrimination value,
A combination for selecting two voltage detectors from each of the voltage detectors is determined for all cases,
For all combinations that select two voltage detectors, compare the magnitude relationship between the absolute value of the difference between the detection voltages of the two voltage detectors and the discrimination value,
When the magnitude relation is compared and the difference voltage absolute value is larger than the discrimination value, a logic H signal is output, and when the difference voltage absolute value is smaller, a logic L signal is output.
ANDing the logic signals for all combinations of two voltage detectors including a particular voltage detector;
A method for detecting an abnormality in the voltage detector, comprising determining whether or not the specific voltage detector is abnormal based on a result of the logical product operation.

The method for detecting an abnormality of a voltage detector according to claim 1 or 2,
An abnormality detection method for a voltage detector, wherein the presence or absence of an abnormality in the voltage detector is determined through a time delay element.