JP2005207928A - Earth detector - Google Patents
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変電所,発電所や大規模プラントにおいては制御のために直流回路が用いられる。通常直流回路にはJEM1090(日本電機工業会規格1090)で定められた直流地絡過電圧継電器64D(直流地絡継電器という)が接続されている。本発明の同期整流のタイミングを自動的に設定する同期整流回路を有する地絡検出装置は,直流地絡が発生したときに,直流地絡継電器64Dに代わって直流回路に接続され,直流回路のN極とアース間に交流信号を生成させ,その交流信号から地絡抵抗に流れる漏れ電流を,変流器ZCTによって検出する直流電路地絡検出装置における,位相調整を自動で行う技術に関する。 In substations, power plants and large-scale plants, DC circuits are used for control. A normal DC circuit is connected to a DC ground fault overvoltage relay 64D (referred to as a DC ground fault relay) defined by JEM1090 (Japan Electrical Manufacturers Association Standard 1090). The ground fault detection device having a synchronous rectification circuit that automatically sets the timing of synchronous rectification of the present invention is connected to a DC circuit instead of the DC ground fault relay 64D when a DC ground fault occurs, The present invention relates to a technology for automatically performing phase adjustment in a DC circuit ground fault detection device that generates an AC signal between an N pole and ground and detects a leakage current flowing from the AC signal to a ground fault resistance by a current transformer ZCT.
従来の地絡検出装置は,図2に示したように信号の経路に参照経路と測定経路があり、参照経路はコンデンサの漏れ電流を検出する零相変流器を入力とするバンドパスフィルタの出力に波形成形回路を設けて参照矩形波を得,測定経路は測定用の零相変流器を入力とするバンドパスフィルタの出力を抵抗成分漏れ電流を測定するためのX軸同期整流回路に接続し,X軸同期整流の同期整流用矩形波として参照矩形波を接続し、理想的なコンデンサの漏れ電流を測定したとき,X軸同期整流の値が0になるように手動で位相調整しておく。該位相調整は図1に示した回路に設けられた半固定抵抗を用いて行う。動作モードには容量補正モードと地絡検出モードがあり,容量補正モードは地絡の無いときに動作させることができ,抵抗成分漏れ電流の値を記憶しておき,地絡検出モードは抵抗成分漏れ電流の測定値から、記憶しておいた抵抗成分漏れ電流を使って,不要な抵抗成分漏れ電流を取り除いて得た抵抗成分漏れ電流により地絡検出を行なうようにした地絡検出装置であった。また,他の例として特許文献1に示した抵抗値測定装置があった。これは電流検出信号と,位相調整手段によって、測定抵抗を介した電流検出信号の位相に一致させた参照信号とを乗算する乗算手段とを備え、この乗算手段の出力に基づき被測定抵抗の純抵抗分を測定する抵抗値測定装置であった。 As shown in FIG. 2, the conventional ground fault detection device has a reference path and a measurement path in the signal path, and the reference path is a band-pass filter input with a zero-phase current transformer that detects the leakage current of the capacitor. A waveform shaping circuit is provided at the output to obtain a reference rectangular wave, and the measurement path is an X-axis synchronous rectifier circuit for measuring the resistance component leakage current using the output of the band-pass filter with a zero-phase current transformer for measurement as input. Connect the reference rectangular wave as the synchronous rectification rectangular wave of X-axis synchronous rectification, and manually adjust the phase so that the X-axis synchronous rectification value becomes 0 when measuring the ideal capacitor leakage current Keep it. The phase adjustment is performed using a semi-fixed resistor provided in the circuit shown in FIG. The operation mode includes a capacitance correction mode and a ground fault detection mode. The capacity correction mode can be operated when there is no ground fault. The resistance component leakage current value is stored, and the ground fault detection mode is a resistance component mode. A ground fault detection device that detects ground faults using resistance component leakage currents obtained by removing unnecessary resistance component leakage currents from the measured leakage current values using the stored resistance component leakage currents. It was. As another example, there is a resistance value measuring apparatus shown in Patent Document 1. This includes a current detection signal and a multiplication means for multiplying the reference signal matched with the phase of the current detection signal via the measuring resistor by the phase adjustment means, and based on the output of this multiplication means, It was a resistance value measuring device for measuring the resistance.
しかしながら,図2に示す従来の直流電路地絡検出装置は製造時に,人手により測定抵抗を介した電流検出信号と参照信号との位相を一致させる調整,即ち同期整流のタイミングの調整作業が必要で,人件費等がかさみ,コストアップするという問題があった。また使用部品の経年変化や温度特性に伴い,容量値が徐々に変化し位相が経時的にずれるため,一定期間後における装置の検査確認の際には,製造時と同じく測定抵抗を介した電流検出信号と参照信号との位相を一致させる必要が生じ,人手により装置を設置する現地での調整も必要になり,調整時間や手間に伴うコストが発生するという問題があった。 However, the conventional DC circuit ground fault detection device shown in FIG. 2 requires manual adjustment of the phase of the current detection signal and the reference signal via the measurement resistor, that is, adjustment of the timing of the synchronous rectification. There was a problem that labor costs increased and costs increased. In addition, the capacitance value gradually changes and the phase shifts with time due to the aging and temperature characteristics of the parts used, so when checking the equipment after a certain period of time, the current through the measuring resistor is the same as during manufacturing. The phase of the detection signal and the reference signal must be matched, and it is necessary to make adjustments at the site where the device is manually installed, resulting in a problem of adjustment time and cost.
地絡がないときには本来地絡の抵抗分(R分)はゼロであるが,現地では回路条件の違いから参照経路と測定経路における入力信号の位相に差が生じ,位相差があるとコンデンサ成分の漏れ電流に加え抵抗成分の漏れ電流が観測される。また対地静電容量は理想的なコンデンサではなく,抵抗成分を直列に含んだ等価回路で表されるため,通常,抵抗成分の漏れ電流が観測される。このような抵抗成分漏れ電流は,地絡による漏れ電流ではないので,地絡検出の点では不要出力といえる。図3に位相ずれによる不要出力の例を示す。ICAがコンデンサ成分の漏れ電流であり,IRAがそれに伴う抵抗成分の漏れ電流,即ち不要出力である。 When there is no ground fault, the resistance of the ground fault (R) is essentially zero, but there is a difference in the phase of the input signal in the reference path and the measurement path due to the difference in circuit conditions. In addition to the leakage current, a resistance component leakage current is observed. In addition, since the capacitance to ground is not an ideal capacitor, it is represented by an equivalent circuit that includes a resistance component in series. Therefore, leakage current of the resistance component is usually observed. Since such a resistance component leakage current is not a leakage current due to a ground fault, it can be said to be an unnecessary output in terms of ground fault detection. FIG. 3 shows an example of unnecessary output due to phase shift. ICA is a leakage current of a capacitor component, and IRA is a leakage current of a resistance component accompanying it, that is, an unnecessary output.
先の容量補正を行なえば,不要出力はキャンセルされるが,経時変化により,地絡発生時の不要出力が大きいと,地絡検出時において誤検出する可能性がある。例えば図3において,対地静電容量が倍になったとすると図3のIRAが倍になり,容量補正で予め記憶した値を差し引いても,IRAの抵抗成分漏れ電流を測定してしまい地絡があると判定する可能性がある。 If the previous capacity correction is performed, the unnecessary output is canceled. However, if the unnecessary output at the time of occurrence of the ground fault is large due to the change over time, there is a possibility of erroneous detection when the ground fault is detected. For example, if the ground capacitance in FIG. 3 is doubled, the IRA in FIG. 3 is doubled, and even if the value stored in advance in the capacitance correction is subtracted, the resistance component leakage current of the IRA is measured and the ground fault occurs. There is a possibility of determining that there is.
また特開平7−72192の抵抗値測定装置の場合,位相調整は不要になるが,乗算器を必要とし,正弦波の作成が複雑であり,増幅器・位相調整手段,乗算手段などの出力電圧の零点の調整を必要とした。したがって回路構成が複雑で高価であり,なおかつ人手による調整が必要があった。 In the case of the resistance value measuring apparatus disclosed in Japanese Patent Application Laid-Open No. 7-72192, phase adjustment is not necessary, but a multiplier is required and the creation of a sine wave is complicated. Needed zero adjustment. Therefore, the circuit configuration is complicated and expensive, and manual adjustment is required.
そこで本件の発明の目的とするところは,測定抵抗を介した電流検出信号と参照信号との位相差を自動的に調整するようにしながらも,安価な回路構成とし,しかも経時変化に伴う部品の容量値変化をも吸収して正確な地絡の抵抗成分の電流を測定できることを可能とした,自動的に同期整流のタイミングを調整する地絡検出装置を提供することを目的としている。 Therefore, the object of the present invention is to automatically adjust the phase difference between the current detection signal via the measuring resistor and the reference signal, but also to provide an inexpensive circuit configuration and to prevent the component with time change. An object of the present invention is to provide a ground fault detection device that automatically adjusts the timing of synchronous rectification, which can accurately measure the current of the resistance component of the ground fault by absorbing the capacitance value change.
上述の目的を達成するために,本発明の請求項1においては,参照経路と測定経路とを有し、
前記参照経路は,コンデンサの漏れ電流を検出する零相変流器と,
該零相変流器の出力信号を入力とする参照用バンドパスフィルタと,
該参照用バンドパスフィルタに接続される参照用波形成形回路とからなり,該参照用波形成形回路の出力により参照矩形波を得、
前記測定経路は,測定用の零相変流器と,
該零相変流器の出力信号を入力とする測定用バンドパスフィルタと,
該測定用のバンドパスフィルタの出力を,測定用矩形波を作成するための測定用波形成形回路と、
抵抗成分漏れ電流を測定するためのX軸同期整流回路と、
コンデンサ成分漏れ電流を測定するためのY軸同期整流回路とに入力し,
これら参照用及び測定用波形成形回路と,X軸同期整流回路と,Y軸同期整流回路と接続されて演算を行う制御回路と,
該制御回路により前記参照矩形波から,該Y軸同期整流回路の同期整流のタイミングと,それから90度遅れたX軸同期整流回路の同期整流のタイミングを自動的に設定することを特徴として地絡検出装置を提供したものである。
In order to achieve the above object, in claim 1 of the present invention, a reference path and a measurement path are provided,
The reference path includes a zero-phase current transformer for detecting a leakage current of the capacitor;
A reference band-pass filter that receives the output signal of the zero-phase current transformer;
A reference waveform shaping circuit connected to the reference bandpass filter, obtaining a reference rectangular wave from the output of the reference waveform shaping circuit,
The measurement path includes a zero-phase current transformer for measurement,
A measurement band-pass filter that receives the output signal of the zero-phase current transformer;
A measurement waveform shaping circuit for producing a measurement rectangular wave from the output of the measurement bandpass filter;
An X-axis synchronous rectifier circuit for measuring resistance component leakage current;
Input to Y-axis synchronous rectifier circuit for measuring capacitor component leakage current,
These reference and measurement waveform shaping circuits, an X-axis synchronous rectifier circuit, a control circuit connected to the Y-axis synchronous rectifier circuit and performing calculations,
The control circuit automatically sets the synchronous rectification timing of the Y-axis synchronous rectifier circuit and the synchronous rectification timing of the X-axis synchronous rectifier circuit delayed by 90 degrees from the reference rectangular wave. A detection device is provided.
また請求項2においては,地絡検出装置の動作モードには,地絡がない場合の待機モードと,装置の設置時もしくは電路における構成変更があった場合に行う容量補正モードと,地絡検出モードがあり,
待機モードの時は,参照用バンドパスフィルタと測定用バンドパスフィルタに校正信号発生装置から同一の校正信号を入力し,参照経路及び測定経路で得られる矩形波差,即ち参照矩形波の変化点から測定矩形波の変化点までの時間を測定し制御回路に記憶し,
容量補正モードの時は,初回のタイミング設定は,Y軸同期整流のタイミングを、参照矩形波の変化点に前記矩形波差を加えたタイミングとして設定し、
2回目以降,タイミング設定を変えて補正を行う条件として、抵抗成分漏れ電流のレベルが一定以上の場合,かつタイミング設定を変える回数が所定の回数以内の場合,かつタイミングとして設定する角度が抵抗成分漏れ電流の測定に支障のない角度である場合,の条件を設け,
これらの条件を満たさない場合には容量補正モードを終了するとともに,そのときの設定タイミングから初回のタイミング設定を引いたタイミング差の値と,抵抗成分漏れ電流の値を制御回路に記憶し,
地絡検出モードの時は,参照矩形波の変化点と矩形波差に,予め記憶しておいたタイミング差の値を加えて同期整流のタイミングとして測定を実施し,
得られた測定値から、記憶しておいた抵抗成分漏れ電流を減算し,不要な抵抗成分漏れ電流を取り除いて抵抗成分漏れ電流を得るよう地絡検出を行なうことを特徴として請求項1記載の地絡検出装置を提供したものである。
Further, according to claim 2, the operation mode of the ground fault detection device includes a standby mode when there is no ground fault, a capacity correction mode performed when the device is installed or when there is a configuration change in the electric circuit, and ground fault detection. There is a mode,
In the standby mode, the same calibration signal is input from the calibration signal generator to the reference bandpass filter and the measurement bandpass filter, and the rectangular wave difference obtained by the reference path and the measurement path, that is, the change point of the reference rectangular wave. To measure the time from the measured square wave to the change point and store it in the control circuit.
In the capacity correction mode, the initial timing is set by setting the Y-axis synchronous rectification timing as the timing obtained by adding the rectangular wave difference to the change point of the reference rectangular wave,
From the second time on, as conditions for correcting by changing the timing setting, if the resistance component leakage current level is above a certain level, if the number of times the timing setting is changed is within a predetermined number, and the angle set as the timing is the resistance component If the angle does not hinder the measurement of leakage current,
When these conditions are not satisfied, the capacity correction mode is terminated, and the timing difference value obtained by subtracting the initial timing setting from the setting timing at that time and the resistance component leakage current value are stored in the control circuit.
In the ground fault detection mode, add the timing difference value stored in advance to the change point of the reference rectangular wave and the rectangular wave difference, and measure the synchronous rectification timing.
The ground fault detection is performed so as to obtain a resistance component leakage current by subtracting the stored resistance component leakage current from the obtained measured value and removing unnecessary resistance component leakage current. A ground fault detection device is provided.
請求項3においては,容量補正モードにおいて同期整流のタイミングを設定する際には,
抵抗成分の漏れ電流をIR,コンデンサ成分の漏れ電流をICとした場合に,
直近の設定タイミングに,ATAN(IR/IC)に相当する時間を加えて,演算することを特徴として請求項2記載の地絡検出装置を提供したものである。
In claim 3, when setting the timing of synchronous rectification in the capacity correction mode,
When the leakage current of the resistance component is IR and the leakage current of the capacitor component is IC,
The ground fault detection apparatus according to claim 2, wherein the calculation is performed by adding a time corresponding to Atan (IR / IC) to the latest set timing.
以上のように本発明によれば,測定抵抗を介した電流検出信号と参照信号との位相差を自動的に調整するようにしながらも,安価な回路構成とし,しかも経時変化に伴う部品の容量値変化をも吸収して正確な地絡の抵抗成分の電流を測定できることを可能とした,自動的に同期整流のタイミングを調整する地絡検出装置を提供することができる。また,本発明により同期整流のタイミング調整,即ち位相調整が人手によらず自動的に行われ,装置を設置する現地での,経時的な位相ずれに伴う調整も不要で,正確に地絡抵抗を検出できる地絡検出装置が実現できる。 As described above, according to the present invention, the phase difference between the current detection signal and the reference signal via the measurement resistor is automatically adjusted, but the circuit configuration is low, and the capacity of the component with time change is also improved. It is possible to provide a ground fault detection device that automatically adjusts the timing of synchronous rectification, which can accurately measure the current of the resistance component of the ground fault by absorbing the value change. In addition, according to the present invention, the timing adjustment of synchronous rectification, that is, the phase adjustment is automatically performed without manual operation, and the adjustment accompanying the phase shift with time is not required at the site where the apparatus is installed, and the ground fault resistance is accurately set. A ground fault detection device capable of detecting
以下,本発明の実施の形態について,図面を用いて詳細に説明する。 Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
図4は本件発明における自動的に同期整流のタイミングを調整する同期整流回路を有する地絡検出装置の実施例を示したものである。同期整流については特開平8−182179号を参照されたい。「同期整流のタイミング」とは,同期整流用矩形波の変化点を意味し,測定波形を,ゼロ電圧を軸にしてプラスマイナス逆に折り返すタイミングである。このタイミングを地絡電流の抵抗成分の波形におけるゼロクロス点になるよう設けると,時間積分した場合に,抵抗成分の値が得られ,コンデンサ成分は抵抗成分から位相が90度進んでいるために積分した場合に出力がキャンセルされ,地絡電流における抵抗成分だけを抽出することが可能である。即ち,後述するが,参照経路と,測定経路を経て得られるそれぞれの矩形波の位相差を予め求めておけば,その位相差を測定に加味して同期整流のタイミングを設けることで,装置部品に係る誤差を測定値からキャンセルすることができる。 FIG. 4 shows an embodiment of a ground fault detection apparatus having a synchronous rectification circuit that automatically adjusts the timing of synchronous rectification in the present invention. For synchronous rectification, refer to JP-A-8-182179. The “synchronous rectification timing” means a change point of the synchronous rectification rectangular wave, and is a timing at which the measured waveform is turned upside down with respect to zero voltage as an axis. If this timing is set so as to be the zero cross point in the waveform of the resistance component of the ground fault current, the value of the resistance component is obtained when time integration is performed, and the capacitor component is integrated because the phase is advanced 90 degrees from the resistance component. In this case, the output is canceled and only the resistance component in the ground fault current can be extracted. That is, as will be described later, if the phase difference between each of the rectangular wave obtained through the reference path and the measurement path is obtained in advance, the timing of the synchronous rectification is set by taking the phase difference into the measurement, thereby providing a device component. Can be canceled from the measured value.
1は電路における直流電源である。Pは直流回路の正極,Nは直流回路の負極である。ZCT(1)〜ZCT(n)は各々の電路に設けられた零相変流器である。2次側の部品は省略してある。REは地絡抵抗で,P極に地絡が発生した場合を示している。RP1,CP1はP極側の,RN1,CN1はN極側の対地静電容量であり,抵抗とコンデンサとの直列回路として等価される。 Reference numeral 1 denotes a DC power source in the electric circuit. P is a positive electrode of the DC circuit, and N is a negative electrode of the DC circuit. ZCT (1) to ZCT (n) are zero-phase current transformers provided in the respective electric circuits. Secondary parts are omitted. RE is a ground fault resistance, and shows a case where a ground fault occurs in the P pole. RP1 and CP1 are on the P pole side, and RN1 and CN1 are ground capacitances on the N pole side, and are equivalent as a series circuit of a resistor and a capacitor.
18は本発明の自動的に同期整流のタイミングを調整する同期整流回路を設けた直流電路地絡検出装置の例である。2は交流信号の生成回路である。アースとN極間に交流信号を生成する。17は低インピーダンスである。 18 is an example of a DC circuit ground fault detection device provided with a synchronous rectification circuit that automatically adjusts the timing of synchronous rectification according to the present invention. Reference numeral 2 denotes an AC signal generation circuit. An AC signal is generated between the ground and the N pole. 17 is a low impedance.
CinP,CinNはそれぞれP極側およびN極側に接続されたコンデンサであり,参照経路に接続された零相変流器ZCTinにコンデンサ成分の漏れ電流を流す。零相変流器の2次側の部品は省略してある。 CinP and CinN are capacitors connected to the P-pole side and the N-pole side, respectively, and flow the leakage current of the capacitor component to the zero-phase current transformer ZCTin connected to the reference path. Parts on the secondary side of the zero-phase current transformer are omitted.
3はバンドパスフィルタであり,ZCTinからの出力が入力され正弦波を出力する。11はバンドパスフィルタに入力される信号の入力選択スイッチである。後述する待機モードにおいて利用する。4は参照経路の波形成形回路である。バンドパスフィルタ3から出力された正弦波が入力され,正弦波のゼロクロス点を変化点とする参照矩形波を発生させる。 Reference numeral 3 denotes a band-pass filter, which receives an output from ZCTin and outputs a sine wave. Reference numeral 11 denotes an input selection switch for a signal input to the band pass filter. Used in a standby mode to be described later. Reference numeral 4 denotes a waveform shaping circuit for the reference path. A sine wave output from the bandpass filter 3 is input, and a reference rectangular wave having a change point at the zero cross point of the sine wave is generated.
15は該Qin1,Qin2,Qout1,Qout2等を含んで構成された制御回路であり,マイコンなどで実現できる。Qin2は参照矩形波の入力部である。5は測定経路のバンドパスフィルタであり,ZCT(1)・・ZCT(n)からの出力が入力され正弦波を出力する。この出力は後述する波形成形回路,X軸同期整流回路,Y軸同期整流回路に入力される。 A control circuit 15 includes the Qin1, Qin2, Qout1, Qout2, etc., and can be realized by a microcomputer or the like. Qin2 is a reference rectangular wave input unit. Reference numeral 5 denotes a bandpass filter of the measurement path, which outputs an output from ZCT (1)... ZCT (n) and outputs a sine wave. This output is input to a waveform shaping circuit, an X-axis synchronous rectifier circuit, and a Y-axis synchronous rectifier circuit described later.
12はバンドパスフィルタの入力選択スイッチであり,後述する待機モードにて利用する。6は測定経路の波形成形回路である。バンドパスフィルタ5から出力された正弦波が入力され,正弦波のゼロクロス点を変化点とする測定矩形波を発生させる。Qin1は測定矩形波の入力部である。 Reference numeral 12 denotes an input selection switch of a bandpass filter, which is used in a standby mode to be described later. Reference numeral 6 denotes a waveform shaping circuit for the measurement path. The sine wave output from the bandpass filter 5 is input, and a measurement rectangular wave having a change point at the zero cross point of the sine wave is generated. Qin1 is an input unit for a measurement rectangular wave.
13はX軸同期整流回路であり,抵抗成分(R成分)漏れ電流IRを出力する。Qout1はX軸同期整流回路に入力される同期整流用矩形波の出力部である。14はY軸同期整流回路であり,コンデンサ成分(C成分)漏れ電流ICを出力する。Qout2はY軸同期整流回路に入力される同期整流用矩形波の出力部である。 An X-axis synchronous rectifier circuit 13 outputs a resistance component (R component) leakage current IR. Qout1 is an output portion of a synchronous rectification rectangular wave input to the X-axis synchronous rectification circuit. A Y-axis synchronous rectifier circuit 14 outputs a capacitor component (C component) leakage current IC. Qout2 is an output unit of a synchronous rectification rectangular wave input to the Y-axis synchronous rectification circuit.
16は校正信号発生部であり,待機モードのときに校正信号を出力し,入力選択スイッチを経て,参照経路と,測定経路のバンドパスフィルタに入力される。 A calibration signal generator 16 outputs a calibration signal in the standby mode, and is input to the reference path and the bandpass filter of the measurement path via the input selection switch.
バンドパスフィルタ3,5は,生成したアースN極間の交流信号のノイズ成分を取り除くために用いている。測定経路と参照経路それぞれに用いられるバンドパスフィルタの部品のバラツキにより,測定経路を経た入力信号の位相と参照経路を経た入力信号の位相とは異なる。 The bandpass filters 3 and 5 are used to remove noise components of the generated AC signal between the grounded N poles. The phase of the input signal that has passed through the measurement path differs from the phase of the input signal that has passed through the reference path due to variations in the components of the bandpass filter used for each of the measurement path and the reference path.
従来は,図1に例示するような位相調整回路で人手により位相がずれないよう合わせていたが,経年変化により,ずれが生じることは先に説明した通りである。 Conventionally, the phase adjustment circuit illustrated in FIG. 1 is adjusted so that the phase is not shifted manually. However, as described above, the shift occurs due to the secular change.
待機モードにおいては入力選択スイッチにより,測定経路及び参照経路のバンドパスフィルタ5,3に校正信号発生回路16が接続され,校正信号発生回路16から同一の校正信号を測定経路のバンドパスフィルタ5と参照経路のバンドパスフィルタ3に入力し,矩形波差すなわち参照矩形波から測定矩形波の変化点の差の時間を測定しておく。この矩形波差が,参照経路と測定経路における位相差となる。この位相差を制御回路に記憶しておく。 In the standby mode, the calibration signal generation circuit 16 is connected to the bandpass filters 5 and 3 of the measurement path and the reference path by the input selection switch, and the same calibration signal is sent from the calibration signal generation circuit 16 to the bandpass filter 5 of the measurement path. Input to the bandpass filter 3 of the reference path, and measure the rectangular wave difference, that is, the time of the difference between the change point of the measurement rectangular wave from the reference rectangular wave. This rectangular wave difference becomes a phase difference between the reference path and the measurement path. This phase difference is stored in the control circuit.
本装置においては直流地絡継電器64Dからの起動信号が入力されない場合,即ち通常時には常に待機モードで動作し,一定時間毎に前記位相差を測定し,その時々の最新の位相差を得ておく。 In this apparatus, when the start signal from the DC ground fault relay 64D is not input, that is, normally, it always operates in the standby mode, and the phase difference is measured at regular intervals to obtain the latest phase difference at that time. .
容量補正モードと地絡検出モードにおいては,入力選択スイッチ12,11により測定経路のバンドパスフィルタ5に測定用の零相変流器を接続し,参照経路のバンドパスフィルタ3には参照用の零相変流器ZCTinを接続する。 In the capacity correction mode and the ground fault detection mode, a zero-phase current transformer for measurement is connected to the bandpass filter 5 of the measurement path by the input selection switches 12 and 11, and the reference path bandpass filter 3 is used for reference. Connect the zero-phase current transformer ZCTin.
制御回路15では,待機モードにおいて予め測定して記憶しておいた最新の位相差即ち矩形波差を参照矩形波に加え,その変化点を,測定経路における電流を検出した変流器から出力される出力信号をバンドパスフィルタ5に入力して得られる正弦波を同期整流する際の同期整流のタイミングとして用いる。すなわち,参照経路の入力を測定経路の入力とした場合の測定経路の正弦波のゼロクロス点を変化点とする同期整流用矩形波が得られる。 The control circuit 15 adds the latest phase difference, that is, the rectangular wave difference measured and stored in advance in the standby mode, to the reference rectangular wave, and outputs the change point from the current transformer that has detected the current in the measurement path. This is used as the timing of synchronous rectification when the sine wave obtained by inputting the output signal to the band pass filter 5 is synchronously rectified. That is, a synchronous rectification rectangular wave having a change point at the zero-cross point of the sine wave of the measurement path when the input of the reference path is used as the input of the measurement path is obtained.
そのため,位相差を加味して同期整流を行うことができるため,X軸同期整流回路13においては,コンデンサ成分をキャンセルすることができ,地絡電流における抵抗成分の地絡電流を得ることができる。したがって人手で位相を調整しなくとも正しい地絡電流の測定が行える。 Therefore, since synchronous rectification can be performed in consideration of the phase difference, the capacitor component can be canceled in the X-axis synchronous rectification circuit 13, and the ground fault current of the resistance component in the ground fault current can be obtained. . Therefore, the correct ground fault current can be measured without manually adjusting the phase.
対地静電容量は図4のRP1,CP1,RN1,CN1に例示するように,抵抗とコンデンサの直列接続である。本発明では容量補正モードのときに対地静電容量即ちコンデンサ成分の電流に位相を合せ,抵抗成分漏れ電流の値を極力小さくすることができる。そのため,対地静電容量の大きさが変化しても抵抗成分漏れ電流としては出力されなくなり,誤検出をなくすことができる。 The ground capacitance is a series connection of a resistor and a capacitor as illustrated in RP1, CP1, RN1, and CN1 in FIG. In the present invention, the value of the resistance leakage current can be made as small as possible by matching the phase with the ground capacitance, that is, the current of the capacitor component in the capacitance correction mode. For this reason, even if the magnitude of the ground capacitance changes, no resistance component leakage current is output, and erroneous detection can be eliminated.
なお,容量補正モードにおいては,初回に測定する同期整流のタイミングとして,参照矩形波の変化点に前記矩形波差を加えたタイミングを用いて演算し,
2回目以降,タイミング設定を変えて補正処理を行う条件として、まず,抵抗成分漏れ電流のレベルが一定以上の場合,即ちゼロから離れていて,ある一定の値以上の抵抗成分漏れ電流が得られる場合に処理を行い,かつタイミング設定を変える回数が所定の回数以内の場合に処理を行い,かつタイミングとして設定する角度が抵抗成分漏れ電流の測定に支障のない角度である場合に処理を行うという条件を設けており,これらの条件を満たさない場合には容量補正モードを終了するとともに,そのときの設定タイミングから初回のタイミング設定を引いたタイミング差の値と,そのときの抵抗成分漏れ電流の値を制御回路に記憶し,待機モードに入る。
In the capacity correction mode, the timing of the first synchronous rectification is calculated using the timing obtained by adding the rectangular wave difference to the change point of the reference rectangular wave,
From the second time, as a condition for performing the correction process by changing the timing setting, first, when the resistance component leakage current level is above a certain level, that is, away from zero, a resistance component leakage current exceeding a certain value is obtained. The processing is performed when the timing setting is changed within the predetermined number of times, and the processing is performed when the angle set as the timing is an angle that does not hinder the measurement of the resistance component leakage current. If these conditions are not met, the capacity correction mode is terminated and the timing difference value obtained by subtracting the initial timing setting from the set timing at that time and the resistance component leakage current at that time The value is stored in the control circuit and the standby mode is entered.
図4のRP1,CP1,RN1,CN1に例示する対地静電容量はほとんどの場合コンデサ成分が主であるが,まれに抵抗成分に相当する負荷がある。そのような場合に位相を合せてしまうと,図5に示したように,位相差θがある場合には,IR成分がIR’で示すように,地絡が生じたときの本来測定すべき抵抗成分漏れ電流の値が小さくなり,その大きさによっては地絡検出ができなくなる場合がある。本発明においては同期整流のタイミング設定を変えて測定する条件の一つにタイミングとして設定する角度が抵抗成分漏れ電流の測定に支障のない角度であることを条件としているので,確実に抵抗成分漏れ電流を測定する事ができる。 In most cases, the capacitances to the ground illustrated in RP1, CP1, RN1, and CN1 in FIG. 4 mainly include a capacitor component, but rarely have a load corresponding to a resistance component. If the phase is adjusted in such a case, as shown in FIG. 5, when there is a phase difference θ, the IR component should be measured originally when a ground fault occurs as indicated by IR ′. The value of the resistance component leakage current becomes small, and depending on the magnitude, the ground fault may not be detected. In the present invention, one of the conditions for measuring by changing the timing setting of the synchronous rectification is that the angle set as the timing is an angle that does not hinder the measurement of the resistance component leakage current. Current can be measured.
次に,抵抗成分漏れ電流の測定に支障のない角度の例を述べる。抵抗成分漏れ電流IRの流れている零相変流器が,容量補正モードにおいて,理想的なコンデンサからδラジアンずれた対地静電容量のキャンセルがしてあるとすると,抵抗成分の漏れ電流の測定値はIR×cosδになる。δが90度に近い場合,抵抗成分漏れ電流の測定値は0に近くなり測定限界に達する程小さい場合には地絡検出ができなくなる。ここで,δの角度が30度までなら位相設定を行うというように角度に制限を設ければ,抵抗成分漏れ電流の値は一番小さくなる場合でも0.866×IRとなり,本来の抵抗成分漏れ電流の約85%の大きさが確保でき,支障なく地絡検出を行うことができる。 Next, examples of angles that do not hinder measurement of resistance component leakage current are described. If the zero-phase current transformer in which the resistance component leakage current IR flows is canceled in the capacitance correction mode, the capacitance of the ground is shifted by δ radians from the ideal capacitor. The value is IR × cos δ. When δ is close to 90 degrees, the measured value of the resistance component leakage current is close to 0, and when it is small enough to reach the measurement limit, the ground fault cannot be detected. Here, if the angle is limited so that the phase is set when the angle of δ is up to 30 degrees, the resistance component leakage current value becomes 0.866 × IR even when the value becomes the smallest, and the original resistance component About 85% of the leakage current can be secured, and ground fault detection can be performed without hindrance.
容量補正モードにおいて,交流信号の生成回路2によって生成する交流信号が,装置を設置する設備に固有のひずみを持つなどの影響で,X軸同期整流の出力の抵抗成分漏れ電流が0にならない場合があるが,その抵抗成分漏れ電流の値を制御回路に記憶しておき,地絡検出モードにおいて反映させるため,地絡検出モードのときに不要出力のキャンセルができる。また同期整流を行う際のタイミング設定を変えて測定する条件の一つに、抵抗成分漏れ電流の値がゼロから離れていることを入力に加味しているのでノイズに位相を合わせることがない。 In the capacity correction mode, when the AC signal generated by the AC signal generating circuit 2 has distortion inherent to the equipment where the equipment is installed, the resistance component leakage current of the output of the X-axis synchronous rectification does not become zero However, since the value of the resistance component leakage current is stored in the control circuit and reflected in the ground fault detection mode, unnecessary output can be canceled in the ground fault detection mode. In addition, as one of the conditions for measurement by changing the timing setting when performing synchronous rectification, the fact that the value of the resistance leakage current is away from zero is taken into account, so that the phase is not matched to noise.
電線の混蝕や電気的な回り込みがある場合,また電源分割がはっきりしていない場合などすなわち,ある経路のP極と,他の経路のN極の間に負荷があるような場合,さらにある経路のP極と他の経路のP極とを接続してしまう場合があり迷走電流が生じるため漏れ電流が大きく変動する。また,負荷電流が流れ地絡抵抗がゼロに近い状態(デッドアースという)場合,漏れ電流が大きく変動する。 There are even cases where there is cable contamination or electrical wraparound, or when the power supply division is not clear, that is, when there is a load between the P pole of one path and the N pole of another path. The P pole of the path may be connected to the P pole of another path, and a stray current is generated, so that the leakage current varies greatly. In addition, when the load current flows and the ground fault resistance is near zero (called dead earth), the leakage current fluctuates greatly.
しかしながら本発明では,タイミング設定を変えて測定する条件として、位相調整を行う回数すなわちタイミング設定を変える回数が所定の回数(最大繰り返し数)以内であることを入れているので,際限なくタイミング設定を行なうことがなくなる。 However, in the present invention, since the number of times of phase adjustment, that is, the number of times of changing the timing setting is within a predetermined number (maximum number of repetitions) as a condition for measuring by changing the timing setting, the timing setting is unlimited. No more to do.
次に,容量補正モードにおいてタイミング設定する場合,どのようなタイミングを設定するかについて説明する。本発明では,直近の設定タイミングにATAN(IR/IC)に相当する時間を加えるようにしてある。そのときのIRとICのずれの大きさはATAN(IR/IC)で計算されるため,減衰曲線的にタイミングをプラス側マイナス側に加減しながら設定して計算を行う方法と比べて真の値に早く収束させられ,位相差を的確に求めることができ,次回のタイミング設定に的確に反映させることができる。 Next, what timing is set when timing is set in the capacity correction mode will be described. In the present invention, a time corresponding to Atan (IR / IC) is added to the latest set timing. Since the magnitude of the difference between IR and IC at that time is calculated by ATRAN (IR / IC), it is more true than the method of calculating by setting the timing to the plus or minus side in the attenuation curve. The phase is quickly converged, and the phase difference can be obtained accurately, which can be accurately reflected in the next timing setting.
以上のように,本発明における地絡検出装置では乗算器を用いておらず,簡単な回路で構成でき,なおかつ調整を不要とすることができる。電子部品そのものは経年変化などにより,特性が変わり位相のずれが生じても,待機モードにおいて常にキャンセルすべき位相差を求めておくことで,正確な測定を行うことができる。即ち,経年変化における位相のずれと,温度変化における位相のずれといった2つの位相ずれの要因を吸収して測定を行うことができる。 As described above, the ground fault detection apparatus according to the present invention does not use a multiplier, can be configured with a simple circuit, and can eliminate the need for adjustment. Even if the characteristics of electronic components themselves change due to aging, etc. and phase shifts occur, accurate measurement can be performed by obtaining the phase difference that should always be canceled in the standby mode. That is, measurement can be performed by absorbing two causes of phase shift, such as phase shift due to secular change and phase shift due to temperature change.
なお,校正信号発生回路16から発生される校正信号は,矩形波でも,正弦波でも三角波でもよい。結果として波形成形回路の出力矩形波の変化点が明確に得られる波形であれば校正信号として利用することができる。低インピーダンス17はヒューズや配線抵抗やノイズ吸収部品などの低インピーダンス部品や必要な場合に追加する低抵抗の合計のインピーダンスであり,地絡抵抗REが0のときにも参照矩形波を発生させることができる。 The calibration signal generated from the calibration signal generation circuit 16 may be a rectangular wave, a sine wave, or a triangular wave. As a result, any waveform that can clearly obtain the changing point of the output rectangular wave of the waveform shaping circuit can be used as a calibration signal. Low impedance 17 is the total impedance of low impedance components such as fuses, wiring resistance, noise absorbing components, and low resistance added when necessary, and generates a reference rectangular wave even when the ground fault resistance RE is zero. Can do.
なお,地絡検出装置においてはマイコンに入力する矩形波は精密に測定するとHigh−Lowのレベルの割合が,Highが50%,Lowが50%ではない場合がほとんどであるが,マイコンから制御出力する矩形波はマイコン内部で処理してHighが50%,Lowが50%のタイミングの設定をすることができるため,同期整流をうまく機能させることができることを書き添えておく。 In the ground fault detection device, when the square wave input to the microcomputer is measured precisely, the ratio of the High-Low level is almost 50% and Low is not 50%. It should be noted that since the rectangular wave to be processed can be set in the microcomputer so that the timing of High is 50% and Low is 50%, the synchronous rectification can function well.
本発明を用いることで回路の位相を自動的に調整することができるため,測定時に位相を調整する必要がある絶縁状態監視装置への応用も可能である。また,直流電路のみならず交流電路においての絶縁状態監視装置での応用も可能である。また,本発明における抵抗成分漏れ電流の出力を得るために同期整流の出力を用いているが,該同期整流の出力として,折り返した波形を生成信号の周期の整数倍時間積分した値を用いて測定を行い,出力値を増大させることでより正確な測定が行えるようになるという可能性がある。 Since the phase of the circuit can be automatically adjusted by using the present invention, it can be applied to an insulation state monitoring device that needs to adjust the phase during measurement. In addition, the present invention can be applied to an insulation state monitoring device in an AC circuit as well as a DC circuit. In addition, the output of the synchronous rectification is used to obtain the output of the resistance component leakage current in the present invention. As the output of the synchronous rectification, a value obtained by integrating the folded waveform with an integral multiple of the period of the generated signal is used. There is a possibility that more accurate measurement can be performed by measuring and increasing the output value.
1 直流電源
2 交流信号の生成回路
3 参照用バンドパスフィルタ
4 参照用波形成形回路
5 測定用バンドパスフィルタ
6 測定用波形成形回路
7 従来の直流電路地絡検出装置
11 参照経路のバンドパスフィルタの入力選択スイッチ
12 測定経路のバンドパスフィルタの入力選択スイッチ
13 X軸同期整流回路
14 Y軸同期整流回路
15 制御回路
16 校正信号発生装置
17 低インピーダンス
18 直流電路地絡検出装置
DESCRIPTION OF SYMBOLS 1 DC power supply 2 AC signal generation circuit 3 Reference band pass filter 4 Reference waveform shaping circuit 5 Measurement band pass filter 6 Measurement waveform shaping circuit 7 Conventional DC circuit ground fault detection device 11 Reference path band pass filter input Selection switch 12 Bandpass filter input selection switch 13 for measurement path X-axis synchronous rectifier circuit 14 Y-axis synchronous rectifier circuit 15 Control circuit 16 Calibration signal generator 17 Low impedance 18 DC circuit ground fault detector
Claims (3)
前記参照経路は,コンデンサの漏れ電流を検出する零相変流器と,
該零相変流器の出力信号を入力とする参照用バンドパスフィルタと,
該参照用バンドパスフィルタに接続される参照用波形成形回路とからなり,該参照用波形成形回路の出力により参照矩形波を得、
前記測定経路は,測定用の零相変流器と,
該零相変流器の出力信号を入力とする測定用バンドパスフィルタと,
該測定用のバンドパスフィルタの出力を,測定用矩形波を作成するための測定用波形成形回路と、
抵抗成分漏れ電流を測定するためのX軸同期整流回路と、
コンデンサ成分漏れ電流を測定するためのY軸同期整流回路とに入力し,
これら参照用及び測定用波形成形回路と,X軸同期整流回路と,Y軸同期整流回路と接続されて演算を行う制御回路と,
該制御回路により前記参照矩形波から,該Y軸同期整流回路の同期整流のタイミングと,それから90度遅れたX軸同期整流回路の同期整流のタイミングを自動的に設定することを特徴とした地絡検出装置。 A reference path and a measurement path,
The reference path includes a zero-phase current transformer for detecting a leakage current of the capacitor;
A reference band-pass filter that receives the output signal of the zero-phase current transformer;
A reference waveform shaping circuit connected to the reference bandpass filter, obtaining a reference rectangular wave from the output of the reference waveform shaping circuit,
The measurement path includes a zero-phase current transformer for measurement,
A measurement band-pass filter that receives the output signal of the zero-phase current transformer;
A measurement waveform shaping circuit for producing a measurement rectangular wave from the output of the measurement bandpass filter;
An X-axis synchronous rectifier circuit for measuring resistance component leakage current;
Input to Y-axis synchronous rectifier circuit for measuring capacitor component leakage current,
These reference and measurement waveform shaping circuits, an X-axis synchronous rectifier circuit, a control circuit connected to the Y-axis synchronous rectifier circuit and performing calculations,
The control circuit automatically sets the synchronous rectification timing of the Y-axis synchronous rectification circuit and the synchronous rectification timing of the X-axis synchronous rectification circuit delayed by 90 degrees from the reference rectangular wave. Fault detector.
待機モードの時は,参照用バンドパスフィルタと測定用バンドパスフィルタに校正信号発生装置から同一の校正信号を入力し,参照経路及び測定経路で得られる矩形波差,即ち参照矩形波の変化点から測定矩形波の変化点までの時間を測定し制御回路に記憶し,
容量補正モードの時は,初回のタイミング設定は,Y軸同期整流のタイミングを、参照矩形波の変化点に前記矩形波差を加えたタイミングとして設定し、
2回目以降,タイミング設定を変えて補正を行う条件として、抵抗成分漏れ電流のレベルが一定以上の場合,かつタイミング設定を変える回数が所定の回数以内の場合,かつタイミングとして設定する角度が抵抗成分漏れ電流の測定に支障のない角度である場合,の条件を設け,
これらの条件を満たさない場合には容量補正モードを終了するとともに,そのときの設定タイミングから初回のタイミング設定を引いたタイミング差の値と,抵抗成分漏れ電流の値を制御回路に記憶し,
地絡検出モードの時は,参照矩形波の変化点と矩形波差に,予め記憶しておいたタイミング差の値を加えて同期整流のタイミングとして測定を実施し,
得られた測定値から、記憶しておいた抵抗成分漏れ電流を減算し,不要な抵抗成分漏れ電流を取り除いて抵抗成分漏れ電流を得るよう地絡検出を行なうことを特徴とする請求項1記載の地絡検出装置。 The operation modes include standby mode when there is no ground fault, capacity correction mode when equipment is installed or when there is a configuration change in the circuit, and ground fault detection mode.
In the standby mode, the same calibration signal is input from the calibration signal generator to the reference bandpass filter and the measurement bandpass filter, and the rectangular wave difference obtained by the reference path and the measurement path, that is, the change point of the reference rectangular wave. To measure the time from the measured square wave to the change point and store it in the control circuit.
In the capacity correction mode, the initial timing is set by setting the Y-axis synchronous rectification timing as the timing obtained by adding the rectangular wave difference to the change point of the reference rectangular wave,
From the second time on, as conditions for correcting by changing the timing setting, if the resistance component leakage current level is above a certain level, if the number of times the timing setting is changed is within a predetermined number, and the angle set as the timing is the resistance component If the angle does not hinder the measurement of leakage current,
When these conditions are not satisfied, the capacity correction mode is terminated, and the timing difference value obtained by subtracting the initial timing setting from the setting timing at that time and the resistance component leakage current value are stored in the control circuit.
In the ground fault detection mode, add the timing difference value stored in advance to the change point of the reference rectangular wave and the rectangular wave difference, and measure the synchronous rectification timing.
2. The ground fault detection is performed so as to obtain a resistance component leakage current by subtracting a stored resistance component leakage current from the obtained measured value and removing an unnecessary resistance component leakage current. Ground fault detection device.
抵抗成分の漏れ電流をIR,コンデンサ成分の漏れ電流をICとした場合に,
直近の設定タイミングに,ATAN(IR/IC)に相当する時間を加えて,演算することを特徴とした請求項2記載の地絡検出装置。
When setting the synchronous rectification timing in the capacity correction mode,
When the leakage current of the resistance component is IR and the leakage current of the capacitor component is IC,
3. The ground fault detection device according to claim 2, wherein the calculation is performed by adding a time corresponding to Atan (IR / IC) to the latest set timing.
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Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
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JP2011155736A (en) * | 2010-01-26 | 2011-08-11 | Sharp Corp | Inverter device and power supply system |
JP2011180053A (en) * | 2010-03-03 | 2011-09-15 | Tokyo Electric Power Co Inc:The | Dc accident point inspection device |
JP2014228519A (en) * | 2013-05-27 | 2014-12-08 | タナシン電機株式会社 | Leak current calculation device and leak current calculation method |
CN104280641A (en) * | 2014-10-23 | 2015-01-14 | 国家电网公司 | Synchronous detection system for intelligent transformer substation device |
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Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
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JP2011155736A (en) * | 2010-01-26 | 2011-08-11 | Sharp Corp | Inverter device and power supply system |
JP2011180053A (en) * | 2010-03-03 | 2011-09-15 | Tokyo Electric Power Co Inc:The | Dc accident point inspection device |
JP2014228519A (en) * | 2013-05-27 | 2014-12-08 | タナシン電機株式会社 | Leak current calculation device and leak current calculation method |
US9465065B2 (en) | 2013-05-27 | 2016-10-11 | Tanashin Denki Co., Ltd. | Leakage current calculation device and method for calculating leakage current |
CN104280641A (en) * | 2014-10-23 | 2015-01-14 | 国家电网公司 | Synchronous detection system for intelligent transformer substation device |
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