JP7013770B2 - Forced grounding device and ground fault search device - Google Patents

Forced grounding device and ground fault search device Download PDF

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JP7013770B2
JP7013770B2 JP2017185544A JP2017185544A JP7013770B2 JP 7013770 B2 JP7013770 B2 JP 7013770B2 JP 2017185544 A JP2017185544 A JP 2017185544A JP 2017185544 A JP2017185544 A JP 2017185544A JP 7013770 B2 JP7013770 B2 JP 7013770B2
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明久 武井
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Tokyo Electric Power Co Inc
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Description

本発明は、電気所の電気機器を操作するシーケンス回路に直流電源を供給する直流電源供給回路の地絡故障を探査するための探査電流を発生させる強制接地装置及び地絡故障探査装置に関する。 The present invention relates to a forced grounding device and a ground fault exploration device that generate an exploration current for exploring a ground fault of a DC power supply circuit that supplies DC power to a sequence circuit that operates an electric device of an electric station.

発変電所や開閉所等の電気所では、遮断器や断路器等の電気機器を操作するシーケンス回路に直流電源を供給する直流電源供給回路が設けられている。この直流電源供給回路は、直流電源装置が接続された直流母線から複数引き出され、さらに、直流電源供給回路から分岐して多数の直流負荷であるシーケンス回路に直流電源を供給する。 Electric stations such as substations and switch stations are provided with a DC power supply circuit that supplies DC power to a sequence circuit that operates electrical equipment such as circuit breakers and disconnectors. A plurality of DC power supply circuits are drawn from the DC bus to which the DC power supply device is connected, and further branch off from the DC power supply circuit to supply DC power to a sequence circuit which is a large number of DC loads.

このような直流電源供給回路においては、直流電源供給回路の地絡故障を検出するための直流地絡継電器（６４Ｄ）が設置されている。直流地絡継電器は、直流電源供給回路の直流母線の正極と負極を抵抗分圧した分圧回路に設けられ、分圧回路の分圧中点は抵抗を介して接地されている。 In such a DC power supply circuit, a DC ground relay (64D) for detecting a ground fault in the DC power supply circuit is installed. The DC ground relay is provided in a voltage dividing circuit in which the positive and negative electrodes of the DC bus of the DC power supply circuit are divided by resistance, and the voltage dividing middle point of the voltage dividing circuit is grounded via a resistor.

このような直流電源供給回路のいずれかで絶縁低下が発生し地絡故障が発生した場合は、直流地絡継電器が動作するので地絡故障が発生したことは検知できるが、地絡故障の箇所を特定することまではできない。そこで、地絡故障が発生したことが検知されると、地絡故障の箇所を探査することになる。地絡故障の箇所を探査する手法として、フリッカ法や低周波重畳法がある。 If insulation deteriorates in any of these DC power supply circuits and a ground fault occurs, the DC ground relay operates so that it can be detected that a ground fault has occurred, but the location of the ground fault failure. Cannot be specified. Therefore, when it is detected that a ground fault has occurred, the location of the ground fault will be searched. There are flicker method and low frequency superimposition method as a method for exploring the location of a ground fault.

図１２は、電気所のシーケンス回路に直流電源を供給する直流電源供給回路の直流回路の回路図である。電気所の直流回路は、直流電源装置１１が接続された直流母線１２から直流電源盤１３の開閉器１４を介して複数の直流電源供給回路１５ａ～１５ｎにそれぞれ直流電源が供給されシーケンス回路１６ａ～１６ｎに直流電源を供給する。図１２中のＣは直流電源供給回路１５ａ～１５ｎの電線の対地静電容量を示している。 FIG. 12 is a circuit diagram of a DC circuit of a DC power supply circuit that supplies DC power to a sequence circuit of an electric station. In the DC circuit of the electric station, DC power is supplied from the DC bus 12 to which the DC power supply device 11 is connected to the plurality of DC power supply circuits 15a to 15n via the switch 14 of the DC power supply panel 13, respectively, and the sequence circuits 16a to A DC power supply is supplied to 16n. C in FIG. 12 shows the ground capacitance of the electric wires of the DC power supply circuits 15a to 15n.

また、各々の直流電源供給回路１５ａ～１５ｎは複数の分岐回路１７を有する。図１２では、直流電源供給回路１５ａは１個の分岐回路１７を有し、直流電源供給回路１５ｂ、１５ｎは２個の分岐回路１７を有したものを示している。図示は省略するが分岐回路１７にも分岐回路を有し、各々の分岐回路にはシーケンス回路が接続され電線の対地静電容量も有している。一方、直流回路の母線１２の正極と負極との間には、正極と負極とを抵抗分圧し分圧中点を抵抗接地した分圧回路１８が設置され、この分圧回路１８は直流回路の地絡故障を検出する直流地絡継電器１９の要素を構成し、直流地絡継電器１９は分圧回路１８の電圧のバランスが崩れたときに動作する。 Further, each DC power supply circuit 15a to 15n has a plurality of branch circuits 17. In FIG. 12, the DC power supply circuit 15a has one branch circuit 17, and the DC power supply circuits 15b and 15n have two branch circuits 17. Although not shown, the branch circuit 17 also has a branch circuit, and a sequence circuit is connected to each branch circuit to have a capacitance to ground of the electric wire. On the other hand, between the positive and negative sides of the bus 12 of the DC circuit, a voltage dividing circuit 18 is installed in which the positive and negative voltages are divided by resistance and the middle point of the voltage dividing is resistance-grounded. It constitutes an element of the DC ground fault relay 19 for detecting a ground fault, and the DC ground fault relay 19 operates when the voltage of the voltage dividing circuit 18 is out of balance.

このような電気所の直流回路に地絡が発生すると直流の地絡電流が流れる。例えば、直流電源供給回路１５ｂのＦ点で地絡抵抗Ｒｆの地絡故障が発生したとすると、図１２の点線矢印で示すように、直流電源装置１１の正極から直流電源盤１３の開閉器１４、地絡故障点Ｆ、分圧回路１８の接地点（中性線）、直流電源装置１１の負極に至る回路が形成され直流の地絡電流が流れる。これにより、分圧回路１８の電圧のバランスが崩れ直流地絡継電器１９が動作するので、直流電源供給回路１５ａ～１５ｎのいずれかに地絡故障が発生したことが分かる。さらに、地絡故障点Ｆを探査するには、各々の直流電源供給回路１５ａ～１５ｎについて、直流の地絡電流が流れているか否かを調査し、地絡故障が発生している直流電源供給回路１５ａ～１５ｎを特定し、地絡故障箇所を特定することになる。この場合、交流の地絡電流の場合には交流電流クランプメータにより容易に検出できるが、直流の地絡電流を検出することが難しい。 When a ground fault occurs in the DC circuit of such an electric place, a DC ground fault current flows. For example, assuming that a ground fault of the ground fault resistance Rf occurs at point F of the DC power supply circuit 15b, as shown by the dotted arrow in FIG. 12, the switch 14 of the DC power supply panel 13 is connected to the positive electrode of the DC power supply device 11. A circuit is formed to reach the ground fault failure point F, the grounding point (neutral wire) of the voltage dividing circuit 18, and the negative electrode of the DC power supply device 11, and a DC ground fault current flows. As a result, the voltage balance of the voltage dividing circuit 18 is lost and the DC ground relay relay 19 operates, so that it can be seen that a ground fault has occurred in any of the DC power supply circuits 15a to 15n. Further, in order to search for the ground fault point F, it is investigated whether or not a DC ground fault current is flowing in each of the DC power supply circuits 15a to 15n, and the DC power supply in which the ground fault has occurred is supplied. The circuits 15a to 15n are specified, and the location of the ground fault failure is specified. In this case, the AC ground fault current can be easily detected by the AC current clamp meter, but it is difficult to detect the DC ground fault current.

そこで、直流地絡継電器１９が動作し地絡故障が発生したことが検出されると、低周波重畳法あるいはフリッカ法により、交流電流クランプメータを用いて地絡故障点Ｆを探査できるようにしている。低周波重畳法は、各々の直流電源供給回路１５ａ～１５ｎに低周波交流電流を強制的に流し、交流電流クランプメータにより、その流した交流電流の探査電流の有無や変化状態で地絡故障点Ｆを探査する方式であり、フリッカ法は、分圧回路１８の接地点にフリッカ装置を接続し、フリッカ装置のフリッカ接点を間欠でオンオフさせ直流電源装置１１から探査電流を発生させ、交流電流クランプメータにより、その流した探査電流を測定して地絡故障点Ｆを探査する方式である。 Therefore, when it is detected that the DC ground relay relay 19 operates and a ground fault has occurred, the ground fault point F can be searched for using an AC current clamp meter by the low frequency superimposition method or the flicker method. There is. In the low-frequency superimposition method, a low-frequency AC current is forcibly passed through each of the DC power supply circuits 15a to 15n, and a ground fault failure point is determined by the presence or absence of the probe current of the passed AC current and the change state by the AC current clamp meter. In the flicker method, a flicker device is connected to the grounding point of the voltage dividing circuit 18, the flicker contacts of the flicker device are intermittently turned on and off to generate an exploration current from the DC power supply device 11, and an AC current clamp is used. This is a method of exploring the ground fault point F by measuring the flowed exploration current with a meter.

図１３は直流電源供給回路の地絡故障点を低周波重畳法で探査する場合の説明図である。図１２と同様に直流電源供給回路１５ｂのＦ点で地絡抵抗Ｒｆの地絡故障が発生したとすると、直流地絡継電器１９が動作し、直流電源供給回路１５ａ～１５ｎのいずれかに地絡故障が発生したことが分かる。低周波重畳法で地絡故障点Ｆを探査するにあたっては、分圧回路１８の接地点（中性線）に低周波交流電源装置２０を接続し、この低周波交流電源装置２０から低周波の交流の探査電流を直流電源供給回路１５ａ～１５ｎに供給する。そうすると、図１３の点線矢印で示すように、低周波交流電源装置２０から分圧回路１８の接地抵抗、分圧回路１８の正極側の分圧抵抗、直流電源盤１３の開閉器１４ｂｐ、地絡故障点Ｆ、低周波交流電源装置２０の接地点に至る回路が形成され、地絡抵抗Ｒｆに探査電流Ｉｐｆが流れる。 FIG. 13 is an explanatory diagram in the case of searching for a ground fault point of a DC power supply circuit by a low frequency superimposition method. As in FIG. 12, if a ground fault of the ground fault resistance Rf occurs at point F of the DC power supply circuit 15b, the DC ground relay relay 19 operates and a ground fault occurs in any of the DC power supply circuits 15a to 15n. It can be seen that a failure has occurred. When searching for the ground fault point F by the low frequency superimposition method, a low frequency AC power supply device 20 is connected to the grounding point (neutral line) of the voltage dividing circuit 18, and the low frequency AC power supply device 20 is used to connect the low frequency AC power supply device 20. The AC exploration current is supplied to the DC power supply circuits 15a to 15n. Then, as shown by the dotted arrow in FIG. 13, the ground resistance of the voltage divider circuit 18 from the low frequency AC power supply device 20, the voltage divider resistance on the positive side of the voltage divider circuit 18, the switch 14bp of the DC power supply panel 13, and the ground fault. A circuit is formed to reach the failure point F and the grounding point of the low-frequency AC power supply device 20, and the exploration current Ipf flows through the ground fault resistance Rf.

また、探査電流は交流電流であることから、低周波交流電源装置２０から分圧回路１８の接地抵抗、分圧回路１８の正極側の分圧抵抗、直流電源盤１３の開閉器１４ｂｐ、直流電源供給回路１５ｂの電線の対地静電容量Ｃｂｐ、低周波交流電源装置２０の接地点に至る回路が形成され、対地静電容量Ｃｂｐに探査電流Ｉｐｃが流れる。さらに、低周波交流電源装置２０から分圧回路１８の接地抵抗、分圧回路１８の負極側の分圧抵抗、直流電源盤１３の開閉器１４ｂｎ、直流電源供給回路１５ｂの電線の対地静電容量Ｃｂｎ、低周波交流電源装置２０の接地点に至る回路が形成され、対地静電容量Ｃｂｎに探査電流Ｉｎｃが流れる。 Further, since the exploration current is an alternating current, the low frequency alternating current power supply device 20 to the ground resistance of the voltage dividing circuit 18, the voltage dividing resistance on the positive side of the voltage dividing circuit 18, the switch 14bp of the DC power supply panel 13, and the DC power supply. A circuit is formed up to the ground capacitance Cbp of the electric wire of the supply circuit 15b and the grounding point of the low-frequency AC power supply device 20, and the exploration current Ipc flows through the ground capacitance Cbp. Further, from the low frequency AC power supply device 20, the ground resistance of the voltage dividing circuit 18, the voltage dividing resistance on the negative side of the voltage dividing circuit 18, the switch 14bn of the DC power supply panel 13, and the ground capacitance of the electric wire of the DC power supply circuit 15b. A circuit is formed to reach the grounding point of the low frequency AC power supply device 20 at Cbn, and the exploration current Inc flows through the ground capacitance Cbn.

地絡故障点Ｆを探査するには、各々の直流電源供給回路１５ａ～１５ｎについて、直流電源盤１３に近い箇所（直流母線１２の近傍）から直流電源供給回路１５の下流の分岐回路１７の分岐点に順次交流電流クランプメータ２１を移動させ直流電源供給回路１５の電線に挟んでクランプし探査電流を測定する。いま、地絡故障点Ｆが発生している直流電源供給回路１５ｂには、交流の探査電流Ｉ１として、地絡抵抗Ｒｆに流れる探査電流Ｉｐｆ、対地静電容量Ｃｂｐに流れる探査電流Ｉｐｃ、対地静電容量Ｃｂｎに流れる探査電流Ｉｎｃを合計した探査電流Ｉ１（＝Ｉｐｆ＋Ｉｐｃ＋Ｉｎｃ）が流れるので、直流電源供給回路１５ｂの直流母線１２の近傍の電線に交流電流クランプメータ２１をクランプした場合には、交流電流クランプメータ２１はこの探査電流Ｉ１を測定することになる。 To search for the ground fault point F, for each of the DC power supply circuits 15a to 15n, the branch circuit 17 downstream of the DC power supply circuit 15 is branched from the location near the DC power supply board 13 (near the DC bus 12). The AC current clamp meter 21 is sequentially moved to the points, sandwiched between the electric wires of the DC power supply circuit 15, and clamped to measure the exploration current. In the DC power supply circuit 15b where the ground fault point F is generated, the AC exploration current I1 is the exploration current Ipf flowing through the ground fault resistance Rf, the exploration current Ipc flowing through the ground capacitance Cbp, and the ground static. Since the exploration current I1 (= Ipf + Ipc + Inc), which is the sum of the exploration currents Inc flowing in the electric capacity Cbn, flows, when the AC current clamp meter 21 is clamped to the electric wire near the DC bus 12 of the DC power supply circuit 15b, the AC current The clamp meter 21 will measure this exploration current I1.

次に、直流電源供給回路１５ｂの分岐回路１７ｂの分岐点の手前の電線に交流電流クランプメータ２１をクランプした場合には、地絡故障点Ｆを通りすぎた箇所であるので、その箇所には、交流の探査電流Ｉ２として、対地静電容量Ｃｂｐに流れる探査電流Ｉｐｃ、対地静電容量Ｃｂｎに流れる探査電流Ｉｎｃを合計した探査電流Ｉ２（＝Ｉｐｃ＋Ｉｎｃ）が流れる。 Next, when the AC current clamp meter 21 is clamped to the electric wire in front of the branch point of the branch circuit 17b of the DC power supply circuit 15b, it is a location that has passed the ground fault failure point F. As the AC exploration current I2, the exploration current I2 (= Ipc + Inc), which is the sum of the exploration current Ipc flowing through the ground capacitance Cbp and the exploration current Inc flowing through the ground capacitance Cbn, flows.

このように、探査電流Ｉ１は地絡抵抗Ｒｆに流れる探査電流Ｉｐｆを含んでいるが、探査電流Ｉ２は地絡抵抗Ｒｆに流れる探査電流Ｉｐｆを含んでいない。このことから、探査電流Ｉ１及び探査電流Ｉ２の電流ベクトルから地絡抵抗Ｒｆを含む成分の有無を判定し、地絡故障点Ｆの箇所を特定できる。つまり、直流母線１２の近傍の電線の下流に地絡故障点Ｆがあり、直流電源供給回路１５ｂの分岐回路１７ｂの分岐点の手前の電線の下流には地絡故障点Ｆがないことが分かるので、この間に地絡故障点Ｆがあると判定
する。 As described above, the exploration current I1 includes the exploration current Ipf flowing through the ground fault resistance Rf, but the exploration current I2 does not include the exploration current Ipf flowing through the ground fault resistance Rf. From this, the presence or absence of the component including the ground fault resistance Rf can be determined from the current vectors of the exploration current I1 and the exploration current I2, and the location of the ground fault failure point F can be specified. That is, it can be seen that there is a ground fault point F downstream of the electric wire in the vicinity of the DC bus 12, and there is no ground fault point F downstream of the electric wire before the branch point of the branch circuit 17b of the DC power supply circuit 15b. Therefore, it is determined that there is a ground fault point F during this period.

しかし、低周波重畳法での地絡故障点の探査は、地絡故障点の地絡抵抗Ｒｆが大きい場合や、直流電源供給回路１５の電線の対地静電容量が大きい場合には、探査電流の検出精度が低下する。地絡故障点の地絡抵抗Ｒｆが大きい場合には探査電流が小さくなり、対地静電容量が大きい場合には相対的に探査電流が小さくなり、検出誤差の範囲に入ってしまうからである。すなわち、対地静電容量の影響を低減するために交流の探査電流は低周波とせざるを得ず、探査電流の周波数と検出精度とが比例する交流電流クランプメータの感度は自ずと低くなるため、地絡故障の検出感度も低いものであった。 However, the search for the ground fault point by the low frequency superimposition method is performed when the ground fault resistance Rf at the ground fault point is large or when the ground capacitance of the electric wire of the DC power supply circuit 15 is large. Detection accuracy is reduced. This is because when the ground fault resistance Rf at the ground fault point is large, the exploration current becomes small, and when the capacitance to ground is large, the exploration current becomes relatively small and falls within the range of the detection error. That is, in order to reduce the influence of the capacitance to ground, the AC exploration current must be set to a low frequency, and the sensitivity of the AC current clamp meter, which is proportional to the frequency of the exploration current and the detection accuracy, is naturally low. The detection sensitivity of the entanglement failure was also low.

図１４は直流電源供給回路の地絡故障点をフリッカ法で探査する場合の説明図である。図１２と同様に直流電源供給回路１５ｂのＦ点で地絡抵抗Ｒｆの地絡故障が発生したとすると、直流地絡継電器１９が動作し、直流電源供給回路１５ａ～１５ｎのいずれかに地絡故障が発生したことが分かる。フリッカ法で地絡故障点Ｆを探査するにあたっては、分圧回路１８の接地点（中性線）にフリッカ装置２２を接続し、フリッカ装置２２のフリッカ接点を間欠でオンオフさせ直流電源装置１１から矩形波脈流の探査電流を発生させ、矩形波脈流の探査電流を直流電源供給回路１５ａ～１５ｎに供給する。 FIG. 14 is an explanatory diagram when searching for a ground fault point of a DC power supply circuit by the flicker method. As in FIG. 12, if a ground fault of the ground fault resistance Rf occurs at point F of the DC power supply circuit 15b, the DC ground relay relay 19 operates and a ground fault occurs in any of the DC power supply circuits 15a to 15n. It can be seen that a failure has occurred. When searching for the ground fault point F by the flicker method, the flicker device 22 is connected to the grounding point (neutral wire) of the voltage dividing circuit 18, and the flicker contact of the flicker device 22 is intermittently turned on and off from the DC power supply device 11. The exploration current of the rectangular wave pulsating current is generated, and the exploration current of the rectangular wave pulsating current is supplied to the DC power supply circuits 15a to 15n.

そうすると、フリッカ装置２２のフリッカ接点がオンのときは分圧回路１８の接地点（中性線）が接地された状態となるので、図１４の点線矢印で示すように、直流電源供給回路１１の正極から直流電源盤１３の開閉器１４ｂｐ、地絡故障点Ｆ、フリッカ装置２２のフリッカ接点（接地点）、分圧回路の分圧抵抗、直流電源供給回路１１の負極に至る回路が形成され、地絡抵抗Ｒｆに探査電流Ｉｐｆが流れる。 Then, when the flicker contact of the flicker device 22 is on, the grounding point (neutral wire) of the voltage dividing circuit 18 is in a grounded state. Therefore, as shown by the dotted arrow in FIG. 14, the DC power supply circuit 11 A circuit is formed from the positive electrode to the switch 14bp of the DC power supply panel 13, the ground fault failure point F, the flicker contact (grounding point) of the flicker device 22, the voltage dividing resistance of the voltage dividing circuit, and the negative electrode of the DC power supply circuit 11. The exploration current Ipf flows through the ground fault resistance Rf.

また、図示は省略するが、探査電流は矩形波脈流の探査電流であることから、矩形波の立ち上がり部分や立ち下がり部分において、対地静電容量Ｃｂｐに探査電流Ｉｐｃが流れ、対地静電容量Ｃｂｎに探査電流Ｉｎｃが流れる。 Although not shown, since the exploration current is the exploration current of the square wave pulsating current, the exploration current Ipc flows through the ground capacitance Cbp at the rising and falling portions of the square wave, and the ground capacitance Exploration current Inc flows through Cbn.

地絡故障点Ｆを探査するには、前述したように、各々の直流電源供給回路１５ａ～１５ｎについて、直流母線１２の近傍から直流電源供給回路１５の下流の分岐回路１７の分岐点に順次交流電流クランプメータ２１を移動させ直流電源供給回路１５の電線にクランプして探査電流を測定する。ここで、地絡故障点Ｆが発生している直流電源供給回路１５ｂには、矩形波脈流の探査電流Ｉ１として、地絡抵抗Ｒｆに流れる探査電流Ｉｐｆ、対地静電容量Ｃｂｐに流れる探査電流Ｉｐｃ、対地静電容量Ｃｂｎに流れる探査電流Ｉｎｃを合計した探査電流Ｉ１（＝Ｉｐｆ＋Ｉｐｃ＋Ｉｎｃ）が流れるが、対地静電容量Ｃｂｐに流れる探査電流Ｉｐｃ、対地静電容量Ｃｂｎに流れる探査電流Ｉｎｃは、矩形波脈流の立ち上がり部分や立ち下がり部分において流れる電流であり、対地静電容量Ｃｂｐに流れる探査電流Ｉｐｃと対地静電容量Ｃｂｎに流れる探査電流Ｉｎｃとは正負の極性が反対であることから足し算したときは相殺される。 In order to search for the ground fault point F, as described above, for each of the DC power supply circuits 15a to 15n, alternating current is sequentially applied from the vicinity of the DC bus 12 to the branch point of the branch circuit 17 downstream of the DC power supply circuit 15. The current clamp meter 21 is moved and clamped to the electric wire of the DC power supply circuit 15 to measure the exploration current. Here, in the DC power supply circuit 15b where the ground fault point F is generated, the exploration current Ipf flowing through the ground fault resistance Rf and the exploration current flowing through the ground capacitance Cbp are used as the exploration current I1 of the rectangular wave pulse flow. The exploration current I1 (= Ipf + Ipc + Inc), which is the sum of the exploration currents Inc flowing in the Ipc and the ground capacitance Cbn, flows, but the exploration current Ipc flowing in the ground capacitance Cbp and the exploration current Inc flowing in the ground capacitance Cbn are rectangular. It is the current that flows in the rising and falling parts of the wave pulse flow, and it is added because the positive and negative polarities of the exploration current Ipc flowing in the ground capacitance Cbp and the exploration current Inc flowing in the ground capacitance Cbn are opposite. Sometimes it is offset.

従って、交流電流クランプメータ２１で測定される探査電流Ｉ１は地絡抵抗Ｒｆに流れる探査電流Ｉｐｆである。直流電源供給回路１５ｂの直流母線１２の近傍の電線に交流電流クランプメータ２１をクランプした場合には、交流電流クランプメータ２１はこの探査電流Ｉ１を測定することになる。なお、探査電流Ｉ１は地絡抵抗Ｒｆに流れる探査電流Ｉｐｆであり、矩形波脈流の探査電流であるので、交流電流クランプメータ２１は矩形波脈流の立ち上がり部分または立ち下がり部分の大きさで探査電流の有無を判定する。 Therefore, the exploration current I1 measured by the AC current clamp meter 21 is the exploration current Ipf flowing through the ground fault resistance Rf. When the AC current clamp meter 21 is clamped to the electric wire in the vicinity of the DC bus 12 of the DC power supply circuit 15b, the AC current clamp meter 21 measures the exploration current I1. Since the exploration current I1 is the exploration current Ipf flowing through the ground fault resistance Rf and is the exploration current of the square wave pulsating current, the AC current clamp meter 21 has the size of the rising portion or the falling portion of the rectangular wave pulsating current. Determine the presence or absence of exploration current.

次に、直流電源供給回路１５ｂの分岐回路１７ｂの分岐点の手前の電線に交流電流クランプメータ２１をクランプした場合には、地絡故障点Ｆを通りすぎた箇所であるので、その箇所には、地絡抵抗Ｒｆに流れる探査電流Ｉｐｆは存在しない。このことから、探査電流Ｉ１及び探査電流Ｉ２に地絡抵抗Ｒｆに流れる探査電流Ｉｐｆの成分を判定することで、地絡故障点Ｆの箇所を特定できる。つまり、探査電流Ｉ１には地絡抵抗Ｒｆに流れる探査電流Ｉｐｆの成分が含まれるので、直流母線１２の近傍の電線の下流に地絡故障点Ｆがあり、直流電源供給回路１５ｂの分岐回路１７ｂの分岐点の手前の電線の下流には地絡抵抗Ｒｆに流れる探査電流Ｉｐｆの成分がないので、地絡故障点Ｆがないことが分かる。従って、この間に地絡故障点Ｆがあると判定する。 Next, when the AC current clamp meter 21 is clamped to the electric wire in front of the branch point of the branch circuit 17b of the DC power supply circuit 15b, it is a location that has passed the ground fault failure point F. , There is no exploration current Ipf flowing through the ground fault resistance Rf. From this, the location of the ground fault point F can be specified by determining the components of the exploration current Ipf flowing through the ground fault resistance Rf in the exploration current I1 and the exploration current I2. That is, since the exploration current I1 contains the component of the exploration current Ipf flowing through the ground fault resistance Rf, there is a ground fault failure point F downstream of the electric wire in the vicinity of the DC bus 12, and the branch circuit 17b of the DC power supply circuit 15b. Since there is no component of the exploration current Ipf flowing through the ground fault resistance Rf downstream of the electric wire in front of the branch point, it can be seen that there is no ground fault failure point F. Therefore, it is determined that there is a ground fault point F during this period.

また、フリッカ法での地絡故障点の探査は、探査電流が矩形波脈流の探査電流であるので、交流電流クランプメータは矩形波脈流の立ち上がり部分または立ち下がり部分の大きさで探査電流の有無を判定することになるので、探査電流をある程度大きくしないと検出精度を向上させることができない。 In addition, since the exploration current is the exploration current of the square wave pulsating current in the search for the ground fault point by the flicker method, the AC current clamp meter uses the size of the rising or falling part of the square wave pulsating current as the exploration current. Since it is determined whether or not the current is present, the detection accuracy cannot be improved unless the exploration current is increased to some extent.

ここで、複数の負荷回路が並列に接続されている直流電回路の地絡検出用直流地絡継電器が地絡電流を検出したとき、フリッカ継電器にてリレー接点を開閉させることにより地絡電流を矩形波脈流に変換して出力し、その矩形波脈流を検出器で検出することで直流接地点を探索するにあたり、矩形波脈流の検出器の回路に交流波形電流の帰還部を接続し、矩形波脈流の検出精度を向上させたものがある（例えば、特許文献１参照）。 Here, when the DC ground fault relay for ground fault detection of a DC electric circuit in which a plurality of load circuits are connected in parallel detects a ground fault current, the ground fault current is rectangularized by opening and closing the relay contact with the flicker relay. When searching for a DC grounding point by converting to a wave pulsating current and outputting it and detecting the rectangular pulsating current with a detector, an AC waveform current feedback unit is connected to the circuit of the rectangular pulsating current detector. , There is one with improved detection accuracy of rectangular wave pulsating current (see, for example, Patent Document 1).

また、特許文献１のものでは、矩形波脈流の検出器（交流電流クランプメータ）の回路に交流波形電流の帰還部を接続し、矩形波脈流の検出精度を向上させているが、フリッカ法での地絡故障点の探査は、矩形波脈流の立ち上がり部分または立ち下がり部分の大きさで探査電流の有無を判定することになるので検出精度の向上には限界がある。 Further, in Patent Document 1, the feedback portion of the AC waveform current is connected to the circuit of the rectangular wave pulsating current detector (AC current clamp meter) to improve the detection accuracy of the rectangular wave pulsating current. In the exploration of the ground fault point by the method, the presence or absence of the exploration current is determined by the size of the rising portion or the falling portion of the rectangular wave pulsating current, so that there is a limit to the improvement of the detection accuracy.

そこで、特許出願人は、直流電源供給回路の地絡故障を安全に精度よく探査できる探査電流を発生させることができる強制接地装置及び地絡故障探査装置を開発し、特願２０１６－１６８２５５号として出願した。 Therefore, the patent applicant has developed a forced grounding device and a ground fault search device that can generate an exploration current that can safely and accurately search for a ground fault in the DC power supply circuit, and as Japanese Patent Application No. 2016-168255. I applied for it.

この強制接地装置は、直流地絡継電器が接続された直流電源供給回路の直流母線の正極と負極との間の分圧回路の分圧中点を非接地とした状態で、地絡故障が発生した直流電源供給回路の直流母線への接続点における健全極の作業用端子に接続され、制限抵抗により探査電流の大きさをシーケンス回路が誤動作しない程度の大きさに制限するとともに、強制接地スイッチにより高感度直流電流クランプメータのゼロ点調整のときはオフして制限抵抗を非接地とし、高感度直流電流クランプメータが地絡故障点を探査するときはオンして制限抵抗を接地し、直流電源装置から直流の探査電流を直流電源供給回路に供給するものである。 In this forced grounding device, a ground fault occurs when the midpoint of the voltage dividing circuit between the positive and negative sides of the DC bus of the DC power supply circuit to which the DC ground fault relay is connected is not grounded. It is connected to the working terminal of the healthy pole at the connection point of the DC power supply circuit to the DC bus, and the size of the exploration current is limited by the limiting resistance to the extent that the sequence circuit does not malfunction, and the forced ground switch is used. When adjusting the zero point of the high-sensitivity DC current clamp meter, turn it off to make the limiting resistor ungrounded. The DC exploration current is supplied from the device to the DC power supply circuit.

また、地絡故障探査装置は、この強制接地装置と、直流電源供給回路の電線にクランプされゼロ点調整を行ってから直流電源装置から供給される直流の探査電流を検出する高感度直流電流クランプメータとを組み合わせたものである。これにより、作業員が、複数の探索対象の分岐回路に高感度直流電流クランプメータを順次設置していき、強制接地装置にて強制接地を行ったときに探査電流が高感度直流電流クランプメータにて検出されると、当該分岐回路に地絡故障事故点があることを特定できる。 In addition, the ground fault detection device is a high-sensitivity DC current clamp that detects the DC exploration current supplied from the DC power supply device after being clamped to the forced grounding device and the electric wire of the DC power supply circuit and adjusting the zero point. It is a combination with a meter. As a result, when a worker sequentially installs high-sensitivity DC current clamp meters in multiple branch circuits to be searched and forcibly grounds them with a forced grounding device, the search current becomes a high-sensitivity DC current clamp meter. When it is detected, it is possible to identify that the branch circuit has a ground fault failure point.

特公平５－３５３８４号公報Tokuhei 5-35384 Gazette

しかし、特願２０１６－１６８２５５号の強制接地装置では、制限抵抗により探査電流の大きさをシーケンス回路が誤動作しない程度の大きさに制限しているので、地絡故障点Ｆの地絡抵抗Ｒｆが大きいと探査電流Ｉｐｆが小さくなり検出し難くなる。特に、地絡抵抗Ｒｆが不安定な場合、探査電流Ｉｐｆが変動するので電流が読み難く探査電流Ｉｐｆの検出が難くなる。 However, in the forced grounding device of Japanese Patent Application No. 2016-168255, the magnitude of the exploration current is limited to a magnitude that does not cause the sequence circuit to malfunction due to the limiting resistance, so that the ground fault resistance Rf at the ground fault failure point F is high. If it is large, the exploration current Ipf becomes small and difficult to detect. In particular, when the ground fault resistance Rf is unstable, the exploration current Ipf fluctuates, so that the current is difficult to read and the exploration current Ipf is difficult to detect.

また、強制接地装置は、直流地絡継電器（６４Ｄ）近傍の作業用端子に接続することになるので、強制接地するための接地操作をする作業員と高感度直流電流クランプメータで探査電流Ｉｐｆの読み取りをするための作業員とが必要となる。地絡故障点Ｆでの地絡状態の把握のために、強制接地装置に電流計を設置して地絡電流を計測表示する場合があるが、強制接地装置の電流計で計測した地絡電流の情報を作業員同士で連絡を取り合わないと、高感度直流電流クランプメータの作業員に報告することができない。 In addition, since the forced grounding device will be connected to the work terminal near the DC ground relay (64D), the exploration current Ipf will be measured by the worker performing the grounding operation for forced grounding and the high-sensitivity DC current clamp meter. A worker is required to read. In order to grasp the ground fault state at the ground fault point F, an ammeter may be installed in the forced grounding device to measure and display the ground fault current, but the ground fault current measured by the current meter of the forced grounding device Unless the workers keep in touch with each other, it is not possible to report the above information to the workers of the high-sensitivity DC ammeter.

強制接地装置の接地箇所で検出される電流は地絡電流であり、高感度直流電流クランプメータで検出される電流は探査電流Ｉｐｆであり、複数の箇所で地絡故障が発生している場合は、地絡電流が複数の地絡故障点を分流することになるので、地絡電流が探査電流Ｉｐｆより大きくなるが、地絡電流と探査電流Ｉｐｆとの突き合わせは作業員同士で連絡を取り合わないと判別することができない。従って、複数の箇所で地絡故障が発生しているか否かの判定が容易でない。 The current detected at the grounding point of the forced grounding device is the ground fault current, and the current detected by the high-sensitivity DC current clamp meter is the exploration current Ipf. , Since the ground fault current divides multiple ground fault points, the ground fault current becomes larger than the exploration current Ipf, but the matching between the ground fault current and the exploration current Ipf does not communicate with each other. Cannot be determined. Therefore, it is not easy to determine whether or not a ground fault has occurred at a plurality of locations.

さらには、地絡故障点Ｆの探査のきっかけとなるのは直流地絡継電器（６４Ｄ）の動作であり、その場合、強制接地装置に設置された電流計で地絡電流を直読できるが、地絡抵抗を直読することができない。地絡故障点Ｆの地絡不具合の度合い（程度）は地絡抵抗により推定できるが、地絡抵抗を把握するには制限抵抗の値を把握して地絡電流及び直流電源電圧から計算しなければならない。 Furthermore, the trigger for exploration of the ground fault point F is the operation of the DC ground relay (64D). In that case, the ammeter installed in the forced grounding device can directly read the ground fault current, but the ground The entanglement resistance cannot be read directly. The degree (degree) of ground fault failure at the ground fault point F can be estimated from the ground fault resistance, but in order to grasp the ground fault resistance, the value of the limiting resistance must be grasped and calculated from the ground fault current and the DC power supply voltage. Must be.

また、大きな変電所などでは、数Ｈｚ程度の長周期の電圧変動が直流電源供給回路に重畳し地絡電流が脈動し変動するので、高感度直流電流クランプ電流計の読みが変動し容易に読みとれないことがある。 Also, in a large substation, a long-period voltage fluctuation of about several Hz is superimposed on the DC power supply circuit and the ground fault current pulsates and fluctuates, so the reading of the high-sensitivity DC current clamp ammeter fluctuates and can be easily read. Sometimes not.

本発明の目的は、電気所の電気機器を操作するシーケンス回路に直流電源を供給する直流電源供給回路の地絡故障点の地絡抵抗の影響を受けずに安定した探査電流を供給できる強制接地装置及び地絡故障探査装置を提供することである。 An object of the present invention is forced grounding that can supply a stable exploration current without being affected by the ground fault resistance of the ground fault failure point of the DC power supply circuit that supplies DC power to the sequence circuit that operates the electrical equipment of the electric station. It is to provide the device and the ground fault search device.

請求項１の発明に係る強制接地装置は、 電気所の電気機器を操作するシーケンス回路に直流電源装置から直流電源を供給する複数の直流電源供給回路のいずれかに地絡故障が発生したとき、前記直流電源供給回路の電線にクランプされゼロ点調整を行ってから前記直流電源装置から供給される直流の探査電流を高感度直流電流クランプメータにより検出して前記地絡故障点を探査する際に、前記地絡故障を検出する直流地絡継電器が接続された前記直流電源供給回路の直流母線の正極と負極との間の分圧回路の分圧中点を非接地とした状態で用いられる強制接地装置であり、
前記地絡故障が発生した前記直流電源供給回路の前記直流母線への接続点における作業用の正極及び負極の作業用端子のうち健全極の作業用端子に接続され、前記直流電源装置から供給される直流の探査電流の大きさを調整して出力する探査電流調整部と、
前記探査電流調整部に直列に接続され前記高感度直流電流クランプメータのゼロ点調整のときはオフして前記直流電源装置から供給される直流の探査電流の大きさを前記シーケンス回路が誤動作しない程度の大きさに制限する制限抵抗を非接地とし、前記高感度直流電流クランプメータが前記地絡故障点を探査するときはオンして前記探査電流調整部を接地し前記直流電源装置から直流の探査電流を前記直流電源供給回路に供給するための強制接地スイッチと、
前記強制接地スイッチに直列接続され前記強制接地スイッチに流れる電流を測定する電流計を備え、
前記探査電流調整部は、前記制限抵抗と、前記制限抵抗に並列に接続され前記探査電流の大きさが予め定めた一定値になるように調整する電流制限回路と、前記制限抵抗と前記電流制限回路とを切り替える切替スイッチとを有したことを特徴とする。
The forced grounding device according to the invention of claim 1 is when a ground fault occurs in any of a plurality of DC power supply circuits that supply DC power from a DC power supply device to a sequence circuit that operates an electric device of an electric place. When searching for the ground fault point by detecting the DC exploration current supplied from the DC power supply device with a high-sensitivity DC current clamp meter after being clamped to the electric wire of the DC power supply circuit and adjusting the zero point. , Forced to be used with the voltage division midpoint of the voltage division circuit between the positive and negative sides of the DC bus of the DC power supply circuit to which the DC ground fault relay for detecting the ground fault failure is ungrounded. It is a grounding device
It is connected to the work terminal of the sound electrode among the work terminals of the positive electrode and the negative electrode for work at the connection point of the DC power supply circuit to the DC bus where the ground fault has occurred, and is supplied from the DC power supply device. The exploration current adjustment unit that adjusts and outputs the magnitude of the DC exploration current to be output,
When the zero point adjustment of the high-sensitivity DC current clamp meter is connected in series with the exploration current adjustment unit, it is turned off to the extent that the sequence circuit does not malfunction the magnitude of the DC exploration current supplied from the DC power supply device. The limiting resistance that limits the size of the current is not grounded, and when the high-sensitivity DC current clamp meter searches for the ground fault point, it is turned on to ground the search current adjustment unit and search for DC from the DC power supply. A forced grounding switch for supplying current to the DC power supply circuit ,
It is equipped with an ammeter that is connected in series to the forced ground switch and measures the current flowing through the forced ground switch.
The exploration current adjusting unit includes the limiting resistor , a current limiting circuit connected in parallel to the limiting resistor and adjusting the magnitude of the exploration current to a predetermined constant value, and the limiting resistor and the current limiting. It is characterized by having a changeover switch for switching between the circuit and the circuit.

請求項２の発明に係る強制接地装置は、請求項１の発明において、前記電流計の近傍に地絡電流に対応する地絡抵抗を表記した目盛り表記部を備えたことを特徴とする。 The forced grounding device according to the second aspect of the present invention is characterized in that, in the first aspect of the present invention, a scale notation portion indicating the ground fault resistance corresponding to the ground fault current is provided in the vicinity of the ammeter.

請求項３の発明の発明に係る地絡故障探査装置は、請求項１または請求項２に記載のいずれかの強制接地装置と、前記直流電源供給回路の電線にクランプされゼロ点調整を行ってから前記直流電源装置から供給される直流の探査電流を検出する高感度直流電流クランプメータとを備えたことを特徴とする。 The ground fault search device according to the invention of claim 3 is clamped to the forced grounding device according to claim 1 or claim 2 and the electric current of the DC power supply circuit to adjust the zero point. It is characterized by being provided with a high-sensitivity DC current clamp meter that detects a DC exploration current supplied from the DC power supply device.

請求項４の発明に係る地絡故障探査装置は、請求項３の発明において、前記強制接地装置の前記強制接地スイッチのオンオフを遠隔操作する接地リモートスイッチと、前記強制接地装置における前記探査電流調整部の前記切替スイッチの切替操作を遠隔操作する切替リモートスイッチと、前記強制接地装置の前記電流計で測定された地絡電流を前記強制接地装置の前記電流計と同等に表示する地絡電流表示器とを有し、前記高感度直流電流クランプメータとともに持ち運ばれる遠隔操作器を備えたことを特徴とする。 In the invention of claim 3, the ground fault search device according to the fourth aspect of the present invention includes a grounding remote switch that remotely controls the on / off of the forced grounding switch of the forced grounding device, and the exploration current adjustment in the forced grounding device. A ground fault current display that displays the ground fault current measured by the changeover remote switch that remotely controls the changeover operation of the changeover switch and the current meter of the forced grounding device in the same manner as the current meter of the forced grounding device. It is characterized by having a device and a remote controller that can be carried together with the high-sensitivity DC current clamp meter.

請求項５の発明に係る地絡故障探査装置は、請求項３または請求項４の発明において、前記高感度直流電流クランプメータに接続され前記高感度直流電流クランプメータで検出された所定期間の探査電流の移動平均電流値を演算する移動平均演算部と、前記移動平均演算部で演算する移動平均電流値の所定期間を設定する所定期間設定部と、前記移動平均演算部の演算のセットまたはリセットを選択する移動平均演算選択スイッチと、前記移動平均演算部で演算された移動平均電流値または前記高感度直流電流クランプメータで検出された電流値を表示出力する探査電流表示器とを有したクランプメータアダプタを備えたことを特徴とする。 In the invention of claim 3 or 4, the ground fault exploration apparatus according to the invention of claim 5 is connected to the high-sensitivity direct current current clamp meter and the exploration for a predetermined period detected by the high-sensitivity direct current clamp meter. A moving average calculation unit that calculates the moving average current value of the current, a predetermined period setting unit that sets a predetermined period of the moving average current value calculated by the moving average calculation unit, and a set or reset of the calculation of the moving average calculation unit. A clamp having a moving average calculation selection switch for selecting, and an exploration current indicator that displays and outputs the moving average current value calculated by the moving average calculation unit or the current value detected by the high-sensitivity DC current clamp meter. It is characterized by being equipped with a meter adapter.

請求項１の発明によれば、直流電源供給回路の地絡故障を探査する際に、直流地絡継電器が接続された直流電源供給回路の直流母線の正極と負極との間の分圧回路の分圧中点を非接地とした状態で強制接地装置を強制接地し、探査電流調整部の電流制限回路から大きさが予め定めた一定値の探査電流を供給できるので、探査電流の検出を容易に行える。 According to the invention of claim 1, when searching for a ground fault of the DC power supply circuit, a voltage dividing circuit between the positive and negative sides of the DC bus of the DC power supply circuit to which the DC ground fault successor is connected The forced grounding device is forcibly grounded with the voltage dividing midpoint ungrounded, and the exploration current of a predetermined value can be supplied from the current limiting circuit of the exploration current adjustment unit, making it easy to detect the exploration current. Can be done.

請求項２の発明によれば、請求項１の発明の効果に加え、電流計の近傍に地絡電流に対応する地絡抵抗を表記した目盛り表記部を備えたので、概略の地絡抵抗を容易に把握でき地絡故障点Ｆの地絡不具合の度合い（程度）を概略で把握できる。 According to the invention of claim 2, in addition to the effect of the invention of claim 1, a scale notation portion indicating the ground fault resistance corresponding to the ground fault current is provided in the vicinity of the ammeter, so that the approximate ground fault resistance can be obtained. It can be easily grasped and the degree (degree) of the ground fault failure at the ground fault failure point F can be roughly grasped.

請求項３の発明によれば、請求項１または請求項２の強制接地装置に、直流電源供給回路の電線にクランプされゼロ点調整を行ってから直流電源から供給される直流の探査電流を検出する高感度直流電流クランプメータを組み合わせて地絡故障探査装置を構成したので、請求項１または請求項２の発明の効果を有した地絡故障探査装置を提供できる。 According to the invention of claim 3, the forced grounding device of claim 1 or 2 detects the DC exploration current supplied from the DC power supply after being clamped to the electric wire of the DC power supply circuit and adjusting the zero point. Since the ground fault search device is configured by combining the high-sensitivity direct current clamp meters, it is possible to provide the ground fault search device having the effect of the invention of claim 1 or 2.

請求項４の発明によれば、請求項３の発明の効果に加え、高感度直流電流クランプメータとともに持ち運ばれる遠隔操作器にて、強制接地装置を強制接地や探査電流調整部の電流制限器と制限抵抗との切り替えを行えるので、強制接地装置を操作をする作業員が不要となる。また、遠隔操作器にて、強制接地装置の電流計で検出した地絡電流の読み取ることができるので、地絡電流と探査電流との突き合わせが容易に行え、複数の箇所で地絡故障が発生していることを容易に判定できる。 According to the invention of claim 4, in addition to the effect of the invention of claim 3, the forced grounding device is forced grounded or the current limiter of the exploration current adjusting unit is a remote controller carried together with the high-sensitivity DC current clamp meter. And the limiting resistance can be switched, eliminating the need for a worker to operate the forced grounding device. In addition, since the ground fault current detected by the ammeter of the forced grounding device can be read by the remote controller, the ground fault current and the exploration current can be easily matched, and ground faults occur at multiple points. You can easily determine what you are doing.

請求項５の発明によれば、請求項３または請求項４の発明の効果に加え、高感度直流電流クランプメータに接続されるクランプメータアダプタにて、高感度直流電流クランプメータで検出された所定期間の探査電流の移動平均演算のセットまたはリセットの選択を可能としているので、数Ｈｚ程度の長周期の電圧変動が直流電源供給回路に重畳し地絡電流が脈動し変動した場合であっても、移動平均値を探査電流表示器に表示させることによって、容易に安定して探査電流を読み取れる。 According to the invention of claim 5, in addition to the effect of the invention of claim 3 or 4, a predetermined value detected by the high-sensitivity direct current clamp meter by the clamp meter adapter connected to the high-sensitivity direct current clamp meter. Since it is possible to select the set or reset of the moving average calculation of the exploration current during the period, even if a long-period voltage fluctuation of about several Hz is superimposed on the DC power supply circuit and the ground fault current pulsates and fluctuates. By displaying the moving average value on the exploration current indicator, the exploration current can be read easily and stably.

本発明の第１実施形態に係る強制接地装置を高感度直流電流クランプメータとを組み合わせることによって地絡故障探査装置を構成し１段目の直流電源回路に高感度直流電流クランプメータをクランプしてゼロ点調整を行っている状態を示す回路図。A ground fault search device is configured by combining the forced grounding device according to the first embodiment of the present invention with a high-sensitivity DC current clamp meter, and the high-sensitivity DC current clamp meter is clamped to the first-stage DC power supply circuit. A circuit diagram showing a state in which zero point adjustment is being performed. 本発明の第１実施形態における強制接地装置の電流計の近傍に設けられる目盛り表記部の説明図。The explanatory view of the scale notation part provided in the vicinity of the ammeter of the forced grounding apparatus in 1st Embodiment of this invention. 本発明の第１実施形態における強制接地装置の電流制限回路の一例を示す回路図。The circuit diagram which shows an example of the current limiting circuit of the forced grounding apparatus in 1st Embodiment of this invention. 図１の状態で高感度直流電流クランプメータのゼロ点調整を行った後に強制接地装置の強制接地スイッチをオンした状態を示す回路図。FIG. 3 is a circuit diagram showing a state in which the forced grounding switch of the forced grounding device is turned on after adjusting the zero point of the high-sensitivity DC current clamp meter in the state of FIG. 図４の状態から次段の２段目の直流電源回路に高感度直流電流クランプメータをクランプしてゼロ点調整を行っている状態を示す回路図。FIG. 6 is a circuit diagram showing a state in which a high-sensitivity DC current clamp meter is clamped to a DC power supply circuit in the second stage of the next stage from the state of FIG. 4 to perform zero point adjustment. 図５の状態で高感度直流電流クランプメータのゼロ点調整を行った後に強制接地装置の強制接地スイッチをオンして探査電流を供給している状態を示す回路図。FIG. 5 is a circuit diagram showing a state in which the forced grounding switch of the forced grounding device is turned on and the exploration current is supplied after the zero point adjustment of the high-sensitivity DC current clamp meter is performed in the state of FIG. 図６の状態で高感度直流電流クランプメータを直流電源供給回路の分岐点の手前の電線に移動させゼロ点調整を行っている状態を示す回路図。FIG. 6 is a circuit diagram showing a state in which a high-sensitivity DC current clamp meter is moved to an electric wire in front of a branch point of a DC power supply circuit to perform zero point adjustment in the state of FIG. 図７の状態で高感度直流電流クランプメータのゼロ点調整を行った後に強制接地装置の強制接地スイッチをオンして探査電流を供給している状態を示す回路図。FIG. 7 is a circuit diagram showing a state in which the exploration current is supplied by turning on the forced grounding switch of the forced grounding device after adjusting the zero point of the high-sensitivity DC current clamp meter in the state of FIG. 7. 本発明の第１実施形態に係る地絡故障探査装置の強制接地装置での地絡電流Ｉｆと地絡抵抗Ｒｆとのグラフである。It is a graph of the ground fault current If and the ground fault resistance Rf in the forced grounding apparatus of the ground fault investigation apparatus which concerns on 1st Embodiment of this invention. 本発明の第２実施形態に係る地絡故障探査装置を構成する強制接地装置及び遠隔操作器の構成図。FIG. 3 is a configuration diagram of a forced grounding device and a remote controller constituting the ground fault detection device according to the second embodiment of the present invention. 本発明の第３実施形態に係る地絡故障探査装置を構成するクランプメータアダプタの構成図。The block diagram of the clamp meter adapter which constitutes the ground fault investigation apparatus which concerns on 3rd Embodiment of this invention. 電気所のシーケンス回路に直流電源を供給する直流電源供給回路の直流回路の回路図。The circuit diagram of the DC circuit of the DC power supply circuit that supplies DC power to the sequence circuit of the electric place. 直流電源供給回路の地絡故障点を低周波重畳法で探査する場合の説明図。Explanatory drawing when searching the ground fault point of the DC power supply circuit by the low frequency superimposition method. 直流電源供給回路の地絡故障点をフリッカ法で探査する場合の説明図。Explanatory drawing when searching for a ground fault point of a DC power supply circuit by the flicker method.

以下、本発明の実施形態を説明する。図１は、本発明の第１実施形態に係る強制接地装置を高感度直流電流クランプメータ２４とを組み合わせることによって地絡故障探査装置を構成し１段目の直流電源回路１５ａに高感度直流電流クランプメータをクランプしてゼロ点調整を行っている状態を示す回路図である。図１では直流電源供給回路１５ｂの正極の電線のＦ点で地絡抵抗Ｒｆの地絡故障が発生し、強制接地装置２３は、地絡故障が発生した直流電源供給回路１５の健全極に接続された場合を示している。すなわち、地絡故障が発生した直流電源供給回路１５の健全極への接続は直流母線１２への接続点における作業用の正極及び負極の作業用端子２５ｐ、２５ｎのうちの健全極（負極）の作業用端子２５ｎに接続された場合を示している。また、高感度直流電流クランプメータ２４は直流電源供給回路１５ａにクランプして高感度直流電流クランプメータ２４のゼロ点調整を行う状態を示している。図１２と同一要素には同一符号を付し重複する説明は省略する。 Hereinafter, embodiments of the present invention will be described. FIG. 1 shows a ground fault exploration device configured by combining the forced grounding device according to the first embodiment of the present invention with a high-sensitivity DC current clamp meter 24, and a high-sensitivity DC current in the first-stage DC power supply circuit 15a. It is a circuit diagram which shows the state which clamps a clamp meter and performs zero point adjustment. In FIG. 1, a ground fault of the ground fault resistance Rf occurs at point F of the positive electrode wire of the DC power supply circuit 15b, and the forced grounding device 23 is connected to the sound pole of the DC power supply circuit 15 in which the ground fault has occurred. It shows the case where it was done. That is, the connection to the healthy electrode of the DC power supply circuit 15 in which the ground fault has occurred is the healthy electrode (negative electrode) of the working terminals 25p and 25n of the working positive electrode and the negative electrode at the connection point to the DC bus 12. The case where it is connected to the work terminal 25n is shown. Further, the high-sensitivity DC current clamp meter 24 shows a state in which the high-sensitivity DC current clamp meter 24 is clamped to the DC power supply circuit 15a to adjust the zero point. The same elements as those in FIG. 12 are designated by the same reference numerals, and duplicate description will be omitted.

ここで、本発明の実施形態で使用する高感度直流電流クランプメータは、例えば、市販の高感度直流電流クランプメータ（マルチ計測器株式会社製、高感度ＤＣクランプメータ、Ｍ－７３０、ＤＣ ０～１００ｍＡ、分解能０．０１ｍＡ）を採用する。これにより、直流地絡継電器が一旦動作するが継続して動作しない程度の地絡故障あるいは直流地絡継電器が動作しない程度の地絡故障であってもその地絡電流を検出できるので故障点を特定することができる。高感度直流電流クランプメータには測定した電流を表示する電流表示器を有している。 Here, the high-sensitivity direct current clamp meter used in the embodiment of the present invention is, for example, a commercially available high-sensitivity direct current clamp meter (manufactured by Multi-Measuring Instrument Co., Ltd., high-sensitivity DC clamp meter, M-730, DC 0 to 100mA, resolution 0.01mA) is adopted. As a result, even if the DC ground relay operates once but does not continue to operate, or even if the DC ground relay does not operate, the ground fault current can be detected. Can be identified. The high-sensitivity DC current clamp meter has a current indicator that displays the measured current.

電気所の直流電源供給回路１５における地絡故障が一旦発生すると、直流地絡継電器１９の動作より検出される。直流地絡継電器１９は故障極を検出し表示するため、直流電源供給回路１５の正極あるいは負極のどちらに故障が発生したかは、直流地絡継電器１９の故障極表示を確認することで把握する。 Once a ground fault in the DC power supply circuit 15 of an electric station occurs, it is detected by the operation of the DC ground relay relay 19. Since the DC ground relay 19 detects and displays a faulty electrode, it is possible to determine whether a failure has occurred in the positive electrode or the negative electrode of the DC power supply circuit 15 by checking the faulty pole display of the DC ground relay. ..

直流地絡継電器１９が動作しない程度の地絡故障の発生把握及び故障極の特定は、直流電源供給回路１５の電圧バランスを定期的に測定することにより確認する。直流電源供給回路１５の正負極の電圧バランス測定は作業用端子２５ｐ、２５ｎにおける正極及び負極の対地電圧の測定により行う。また、作業用端子２５が各々の直流電源供給回路１５ａ～１５ｎの正極及び負極に個別に設けられる場合には、個別の作業用端子２５につき正極及び負極の電圧バランスを測定することにより、健全極を特定できる。 The occurrence of a ground fault failure to the extent that the DC ground relay relay 19 does not operate and the identification of the failure pole are confirmed by periodically measuring the voltage balance of the DC power supply circuit 15. The voltage balance of the positive and negative electrodes of the DC power supply circuit 15 is measured by measuring the voltage to ground of the positive and negative electrodes at the working terminals 25p and 25n. When the working terminals 25 are individually provided on the positive and negative electrodes of the DC power supply circuits 15a to 15n, the voltage balance between the positive and negative electrodes is measured for each working terminal 25 to obtain a healthy electrode. Can be identified.

以下の説明では、直流地絡継電器１９の動作により、電気所の直流電源供給回路１５ａ～１５ｎのいずれかに地絡故障が発生したことが検出された場合について説明する。直流電源供給回路１５における地絡故障の発生把握及び故障極の特定は直流地絡継電器１９の故障極表示を確認して行う。 In the following description, a case where it is detected that a ground fault has occurred in any of the DC power supply circuits 15a to 15n of the electric station due to the operation of the DC ground relay relay 19 will be described. The occurrence of a ground fault in the DC power supply circuit 15 and the identification of the faulty pole are confirmed by checking the faulty pole display of the DC ground relay relay 19.

直流地絡継電器１９の動作により、電気所の直流電源供給回路１５ａ～１５ｎのいずれかに地絡故障が発生したことが検出されると、強制接地装置２３は、地絡故障を検出する直流地絡継電器１９の分圧回路１８の分圧中点を非接地とした状態で用いられる。これは、強制接地装置２３は、直流電源装置１１から直流の探査電流を直流電源供給回路１５に供給するものであり、地絡故障点以外の接地点である分圧回路１８の分圧中点に探査電流が流れるのを阻止するためである。分圧回路１８の分圧中点を非接地とすることで探査電流の検出精度を高めることができる。 When it is detected that a ground fault has occurred in any of the DC power supply circuits 15a to 15n of the electric station due to the operation of the DC ground relay, the forced grounding device 23 detects the ground fault. It is used in a state where the voltage dividing midpoint of the voltage dividing circuit 18 of the relay electric device 19 is not grounded. This is because the forced grounding device 23 supplies a DC exploration current from the DC power supply device 11 to the DC power supply circuit 15, and is a voltage dividing middle point of the voltage dividing circuit 18 which is a grounding point other than the ground fault failure point. This is to prevent the exploration current from flowing in. By making the voltage dividing midpoint of the voltage dividing circuit 18 ungrounded, the detection accuracy of the exploration current can be improved.

ここで、作業用端子２５は各々の直流電源供給回路１５ａ～１５ｎの正極及び負極に個別に設けられる場合、各々の直流電源供給回路１５ａ～１５ｎの正極及び負極に共通に設けられる場合があるが、図１では共通に設けられた作業用端子２５ｐ、２５ｎを示している。すなわち、各々の直流電源供給回路１５ａ～１５ｎに対し、正極には共通の作業用端子２５ｐが設けられ、負極には作業用端子２５ｎが共通に設けられている場合を示している。 Here, when the working terminal 25 is individually provided on the positive electrode and the negative electrode of each DC power supply circuit 15a to 15n, it may be commonly provided on the positive electrode and the negative electrode of each DC power supply circuit 15a to 15n. , FIG. 1 shows working terminals 25p and 25n which are commonly provided. That is, for each of the DC power supply circuits 15a to 15n, a common working terminal 25p is provided on the positive electrode, and a working terminal 25n is commonly provided on the negative electrode.

以下の説明では、作業用端子２５は各々の直流電源供給回路１５ａ～１５ｎの正極及び負極に共通に設けられている場合について説明する。すなわち、図１では、強制接地装置２３を、地絡故障が発生した直流電源供給回路１５の直流母線１２への接続点における作業用の正極及び負極の作業用端子２５のうち健全極の共通の作業用端子２５ｎに接続した場合を示している。 In the following description, a case where the working terminal 25 is provided in common to the positive electrode and the negative electrode of the respective DC power supply circuits 15a to 15n will be described. That is, in FIG. 1, the forced grounding device 23 is common to the healthy electrodes of the working positive electrode and the working terminal 25 of the working positive electrode and the negative electrode at the connection point of the DC power supply circuit 15 where the ground fault has occurred to the DC bus 12. The case where it is connected to the work terminal 25n is shown.

強制接地装置２３は、探査電流調整部２６、強制接地スイッチ２７及び電流計２８を直列に接続して構成されている。電流計２８の近傍には目盛り表記部２９が設けられている。目盛り表記部２９は地絡電流に対応する地絡抵抗を表記したものである。 The forced grounding device 23 is configured by connecting the exploration current adjusting unit 26, the forced grounding switch 27, and the ammeter 28 in series. A scale notation unit 29 is provided in the vicinity of the ammeter 28. The scale notation unit 29 indicates the ground fault resistance corresponding to the ground fault current.

探査電流調整部２６は、直流電源装置から供給される直流の探査電流の大きさを調整して出力するものであり、制限抵抗３０に並列に電流制限回路３１が接続されて構成され、さらに、制限抵抗３０と電流制限回路３１とを切り替える切替スイッチ３２を有している。なお、電流制限回路３１に直列に接続された抵抗３３は、電流制限回路３１が短絡故障した場合に過大電流が流れるのを防止するための保護抵抗である。制限抵抗３０は、直流電源装置１１から供給される直流の探査電流の大きさをシーケンス回路１６が誤動作しない程度の大きさに制限する抵抗である。また、電流制限回路３１は、地絡抵抗Ｒｆの大きさに関係なく探査電流の大きさが予め定めた一定値でシーケンス回路１６が誤動作しない程度の大きさになるように調整するものである。 The exploration current adjusting unit 26 adjusts and outputs the magnitude of the DC exploration current supplied from the DC power supply device, and is configured by connecting the current limiting circuit 31 in parallel to the limiting resistance 30 and further. It has a changeover switch 32 for switching between the limiting resistance 30 and the current limiting circuit 31. The resistance 33 connected in series with the current limiting circuit 31 is a protection resistance for preventing an excessive current from flowing when the current limiting circuit 31 has a short-circuit failure. The limiting resistor 30 is a resistor that limits the magnitude of the DC exploration current supplied from the DC power supply device 11 to such a magnitude that the sequence circuit 16 does not malfunction. Further, the current limiting circuit 31 is adjusted so that the magnitude of the exploration current is a predetermined constant value regardless of the magnitude of the ground fault resistance Rf so that the sequence circuit 16 does not malfunction.

強制接地スイッチ２７はオンのときに直流電源装置１１から直流の探査電流を直流電源供給回路１５に供給するためのスイッチである。図１では強制接地スイッチ２７はオフの状態であり、この状態では直流電源装置１１から直流の探査電流は直流電源供給回路１５に供給されない。また、電流計２８は強制接地スイッチ２７に直列接続され、強制接地スイッチ２７に流れる電流を測定し表示出力する。前述したように、電流計２８の近傍には目盛り表記部２９が設けられている。 The forced grounding switch 27 is a switch for supplying a DC exploration current from the DC power supply device 11 to the DC power supply circuit 15 when it is on. In FIG. 1, the forced grounding switch 27 is in the off state, and in this state, the DC exploration current is not supplied from the DC power supply device 11 to the DC power supply circuit 15. Further, the ammeter 28 is connected in series to the forced grounding switch 27, measures the current flowing through the forced grounding switch 27, and outputs a display. As described above, a scale notation unit 29 is provided in the vicinity of the ammeter 28.

図２は目盛り表記部２９の説明図である。目盛り表記部２９の上段には地絡電流Ｉｆの地絡電流目盛り部２９Ａが表記され、目盛り表記部２９の下段には地絡電流Ｉｆに対応して地絡抵抗Ｒｆの地絡抵抗目盛り部２９Ｂが表記されている。
目盛り表記部２９は、地絡電流目盛り部２９Ａと地絡抵抗目盛り部２９Ｂとで、探査電流調整部２６の選択スイッチ３２で制限抵抗３０を選択した際の地絡電流Ｉｆと地絡抵抗Ｒｆとの関係を示している。 FIG. 2 is an explanatory diagram of the scale notation unit 29. The ground fault current scale part 29A of the ground fault current If is written in the upper part of the scale notation part 29, and the ground fault resistance scale part 29B of the ground fault resistance Rf corresponds to the ground fault current If in the lower part of the scale notation part 29. Is written.
The scale notation unit 29 is a ground fault current scale unit 29A and a ground fault resistance scale unit 29B, and the ground fault current If and the ground fault resistance Rf when the limiting resistor 30 is selected by the selection switch 32 of the exploration current adjusting unit 26. Shows the relationship.

直流電源装置１１の直流電圧がＥであるとすると、地絡電流Ｉｆは（１）式で示され、地絡抵抗Ｒｆは（２）式で示される。 Assuming that the DC voltage of the DC power supply device 11 is E, the ground fault current If is expressed by the equation (1), and the ground fault resistance Rf is expressed by the equation (2).

Ｉｆ＝Ｅ／（Ｒｆ＋制限抵抗） …（１）
Ｒｆ＝Ｅ／Ｉｆ－制限抵抗 …（２）
いま、直流電源装置１１の直流電圧Ｅが１１０Ｖ、制限抵抗３０が１００ｋΩであるとすると、Ｒｆ＝１１０／Ｉｆ－１００となる。この場合、地絡電流Ｉｆが１．１ｍＡであるときは地絡抵抗Ｒｆは０、地絡電流Ｉｆが１．０ｍＡであるときは地絡抵抗Ｒｆは１０ｋΩ、地絡電流Ｉｆが０．５ｍＡであるときは地絡抵抗Ｒｆは１２０ｋΩとなる。このように、電流計２８で計測された地絡電流を目盛り表記部２９により地絡抵抗Ｒｆに容易に換算できるので、概略の地絡抵抗Ｒｆを容易に把握でき地絡故障点Ｆの地絡不具合の度合い（程度）を概略で把握できる。 If = E / (Rf + limiting resistance) ... (1)
Rf = E / If-Limited resistance ... (2)
Assuming that the DC voltage E of the DC power supply device 11 is 110 V and the limiting resistance 30 is 100 kΩ, Rf = 110 / If-100. In this case, when the ground fault current If is 1.1 mA, the ground fault resistance Rf is 0, and when the ground fault current If is 1.0 mA, the ground fault resistance Rf is 10 kΩ and the ground fault current If is 0.5 mA. At one time, the ground fault resistance Rf becomes 120 kΩ. In this way, since the ground fault current measured by the ammeter 28 can be easily converted into the ground fault resistance Rf by the scale notation unit 29, the approximate ground fault resistance Rf can be easily grasped and the ground fault at the ground fault failure point F. The degree (degree) of the defect can be roughly grasped.

図３は電流制限回路３１の一例を示す回路図である。電流制限回路３１は定電流ダイオード３４とダイオードブリッジ回路３５とで構成され、定電流ダイオード３４は０［Ｖ］～Ｖk［Ｖ］の領域では印加電圧に比例して電流値が増減するがＶk［Ｖ］を超えると一定の電流（ピンチオフ電流）を流す素子である。電流制限回路３１は双方向特性を持たせるためにダイオードブリッジ回路３５を設けている。図３では定電流ダイオード３４を用いて構成した電流制限回路３１を示しているが、電流制限回路３１はトランジスタを用いて一定の電流を流す回路を構成するようにしてもよい。 FIG. 3 is a circuit diagram showing an example of the current limiting circuit 31. The current limiting circuit 31 is composed of a constant current diode 34 and a diode bridge circuit 35. The constant current diode 34 increases or decreases in proportion to the applied voltage in the range of 0 [V] to Vk [V], but Vk [ V] is an element that allows a constant current (pinch-off current) to flow. The current limiting circuit 31 is provided with a diode bridge circuit 35 in order to have bidirectional characteristics. Although FIG. 3 shows a current limiting circuit 31 configured by using a constant current diode 34, the current limiting circuit 31 may be configured to flow a constant current by using a transistor.

次に、直流電源供給回路１５の地絡故障点Ｆを探査するには、探査電流調整部２６の選択スイッチ３２で制限抵抗３０を選択し、強制接地スイッチ２７を閉じて制限抵抗３０（例えば１００ｋΩ）で接地する。そして、電流計２８の電流（地絡電流）を読み取り、電流の変動や大きさを確認することで故障点の様相を判別する。その際に前述したように目盛り表記部２９を参照して地絡抵抗を推定する。この後、強制接地スイッチ２７を開いて探査電流調整部２６の選択スイッチ３２で電流制限回路３１を選択し、電流制限回路３１による定電流（例えば１ｍＡ）で地絡探査を行うことになる。 Next, in order to search for the ground fault point F of the DC power supply circuit 15, the limiting resistance 30 is selected by the selection switch 32 of the exploration current adjusting unit 26, the forced grounding switch 27 is closed, and the limiting resistance 30 (for example, 100 kΩ) is closed. ) To ground. Then, the aspect of the failure point is determined by reading the current (ground fault current) of the ammeter 28 and confirming the fluctuation and magnitude of the current. At that time, as described above, the ground fault resistance is estimated with reference to the scale notation unit 29. After that, the forced grounding switch 27 is opened, the current limiting circuit 31 is selected by the selection switch 32 of the exploration current adjusting unit 26, and the ground fault exploration is performed with the constant current (for example, 1 mA) by the current limiting circuit 31.

電流制限回路３１を選択した後、強制接地装置２３の強制接地スイッチ２７がオフの状態で、各々の直流電源供給回路１５ａ～１５ｎについて、直流母線１２の近傍から直流電源供給回路１５の下流の分岐回路１７の分岐点に向けて順次高感度直流電流クランプメータ２４を移動させ、移動の度にゼロ点調整を行い強制接地装置２３の強制接地スイッチ２７を閉じて探査電流を測定して地絡故障点を特定することになる。前述したように高感度直流電流クランプメータ２４には測定した電流を表示する電流表示を有しているので、作業員は測定した電流を容易に把握できる。 After selecting the current limiting circuit 31, with the forced grounding switch 27 of the forced grounding device 23 turned off, each DC power supply circuit 15a to 15n is branched downstream from the vicinity of the DC bus 12 to the downstream of the DC power supply circuit 15. The high-sensitivity DC current clamp meter 24 is sequentially moved toward the branch point of the circuit 17, the zero point is adjusted each time the meter is moved, the forced grounding switch 27 of the forced grounding device 23 is closed, and the exploration current is measured to cause a ground fault. You will identify the point. As described above, since the high-sensitivity DC current clamp meter 24 has a current display for displaying the measured current, the operator can easily grasp the measured current.

高感度直流電流クランプメータ２４のゼロ点調整を行うのは、高感度直流電流クランプメータ２４は２次側に交流バイアスを流して直流の電流を検出するものであることから、ゼロ点オフセットを補正するために測定の度にゼロ点調整を必要とするからである。 The zero point adjustment of the high-sensitivity DC current clamp meter 24 is performed because the high-sensitivity DC current clamp meter 24 detects the direct current by passing an AC bias to the secondary side, so that the zero point offset is corrected. This is because the zero point adjustment is required for each measurement.

まず、強制接地装置２３の強制接地スイッチ２７を開いた状態で、直流電源供給回路の１段目の直流電源回路１５ａの電線に高感度直流電流クランプメータをクランプしてゼロ点調整を行う。そして、高感度直流電流クランプメータ２４のゼロ点調整を行った後に、図４に示すように、強制接地装置２３の強制接地スイッチ２７をオンにする。切替スイッチ３２により電流制限回路３１が選択されているので、強制接地装置２３の強制接地スイッチ２７のオンにより、直流電源供給回路１５ａに地絡故障が発生している場合には、直流電源装置１１から直流の探査電流を直流電源供給回路１５ａに供給できる状態となるが、直流電源供給回路１５ａには地絡故障が発生していないので、強制接地装置２３の強制接地スイッチ２７をオンしても探査電流は流れない。従って、高感度直流電流クランプメータ２４は探査電流を検出しないので、直流電源供給回路１５ａには地絡故障が発生していないことが分かる。 First, with the forced grounding switch 27 of the forced grounding device 23 open, a high-sensitivity DC current clamp meter is clamped to the electric wire of the first-stage DC power supply circuit 15a of the DC power supply circuit to adjust the zero point. Then, after adjusting the zero point of the high-sensitivity DC current clamp meter 24, the forced grounding switch 27 of the forced grounding device 23 is turned on as shown in FIG. Since the current limiting circuit 31 is selected by the changeover switch 32, if a ground fault has occurred in the DC power supply circuit 15a due to the forced grounding switch 27 of the forced grounding device 23 being turned on, the DC power supply device 11 However, since no ground fault has occurred in the DC power supply circuit 15a, even if the forced grounding switch 27 of the forced grounding device 23 is turned on, the DC exploration current can be supplied to the DC power supply circuit 15a. No exploration current flows. Therefore, since the high-sensitivity DC current clamp meter 24 does not detect the exploration current, it can be seen that no ground fault has occurred in the DC power supply circuit 15a.

次に、１段目の直流電源回路１５ａには地絡故障は発生していないので、図５に示すように、次段の２段目の直流電源回路１５ｂの電線に高感度直流電流クランプメータをクランプしてゼロ点調整を行う。そして、高感度直流電流クランプメータ２４のゼロ点調整を行った後に、図６に示すように、強制接地装置２３の強制接地スイッチ２７をオンにする。 Next, since no ground fault has occurred in the first-stage DC power supply circuit 15a, as shown in FIG. 5, a high-sensitivity DC current clamp meter is attached to the electric wire of the second-stage DC power supply circuit 15b in the next stage. Clamp to adjust the zero point. Then, after adjusting the zero point of the high-sensitivity DC current clamp meter 24, the forced grounding switch 27 of the forced grounding device 23 is turned on as shown in FIG.

図６に示すように、２段目の直流電源回路１５ｂには地絡故障が発生しているので、強制接地装置２３の強制接地スイッチ２７をオンすると、直流電源装置１１の正極から直流電源盤１３の開閉器１４ｂｐ、地絡故障点Ｆ、強制接地装置２３の電流制限回路３１及び保護抵抗３３、健全極の作業用端子２５ｎ、直流電源装置１１の負極に至る回路が形成され直流の探査電流が流れる。探査電流は直流の定電流であることから直流電源供給回路１５ｂの電線の対地静電容量Ｃｂｐには流れない。 As shown in FIG. 6, since a ground fault has occurred in the second-stage DC power supply circuit 15b, when the forced grounding switch 27 of the forced grounding device 23 is turned on, the DC power supply panel is connected to the positive electrode of the DC power supply device 11. A circuit is formed to reach the switch 14bp of the switch 13, the ground fault failure point F, the current limiting circuit 31 and the protection resistor 33 of the forced grounding device 23, the working terminal 25n of the sound pole, and the negative electrode of the DC power supply device 11, and the DC exploration current. Flows. Since the exploration current is a DC constant current, it does not flow in the ground capacitance Cbp of the electric wire of the DC power supply circuit 15b.

この状態で、高感度直流電流クランプメータ２４は、探査電流検出スイッチを操作にして、クランプした直流電源供給回路１５ｂの電線に流れる直流の探査電流を検出する。前述したように、強制接地スイッチ２７に直列接続された電流制限回路３１は、地絡抵抗Ｒｆの大きさに関係なく予め定めた一定値の探査電流を出力するものであるので、高感度直流電流クランプメータ２４は探査電流を容易に検出できる。また、電流制限回路３１から出力される探査電流の大きさはシーケンス回路１６が誤動作しない程度の大きさであるので、シーケンス回路１６を誤操作させることはない。 In this state, the high-sensitivity DC current clamp meter 24 operates the exploration current detection switch to detect the DC exploration current flowing through the electric wire of the clamped DC power supply circuit 15b. As described above, the current limiting circuit 31 connected in series to the forced grounding switch 27 outputs a predetermined constant value exploration current regardless of the magnitude of the ground fault resistance Rf, and therefore has a high-sensitivity direct current. The clamp meter 24 can easily detect the exploration current. Further, since the magnitude of the exploration current output from the current limiting circuit 31 is such that the sequence circuit 16 does not malfunction, the sequence circuit 16 will not be erroneously operated.

図６の状態では、高感度直流電流クランプメータ２４は探査電流を検出するので、直流電源供給回路１５ｂの直流電源盤１３より下流に地絡故障が発生していることが分かる。次に、直流電源供給回路１５ｂの分岐回路１７ｂの分岐点の手前の電線に交流電流クランプメータ２１をクランプして高感度直流電流クランプメータ２４により探査電流を検出することになるが、前述したように、高感度直流電流クランプメータ２４は測定の度にゼロ点調整を必要とするから、強制接地装置２３の強制接地スイッチ２７をオフにして高感度直流電流クランプメータ２４のゼロ点調整を行う。 In the state of FIG. 6, since the high-sensitivity DC current clamp meter 24 detects the exploration current, it can be seen that a ground fault has occurred downstream of the DC power supply panel 13 of the DC power supply circuit 15b. Next, the AC current clamp meter 21 is clamped to the electric wire in front of the branch point of the branch circuit 17b of the DC power supply circuit 15b, and the exploration current is detected by the high-sensitivity DC current clamp meter 24. In addition, since the high-sensitivity DC current clamp meter 24 requires zero-point adjustment for each measurement, the forced grounding switch 27 of the forced grounding device 23 is turned off to adjust the zero-point of the high-sensitivity DC current clamp meter 24.

図７は、図６の状態で高感度直流電流クランプメータを直流電源供給回路の分岐点の手前の電線に移動させゼロ点調整を行っている状態を示す回路図である。図７に示すように、高感度直流電流クランプメータ２４を次の測定箇所である直流電源供給回路１５ｂの分岐回路１７ｂの分岐点の手前の電線に移動させ、強制接地装置２３の強制接地スイッチ２７をオフにする。この状態で、高感度直流電流クランプメータ２４のゼロ点調整を行う。 FIG. 7 is a circuit diagram showing a state in which the high-sensitivity DC current clamp meter is moved to the electric wire in front of the branch point of the DC power supply circuit to adjust the zero point in the state of FIG. As shown in FIG. 7, the high-sensitivity DC current clamp meter 24 is moved to the electric wire in front of the branch point of the branch circuit 17b of the DC power supply circuit 15b, which is the next measurement point, and the forced grounding switch 27 of the forced grounding device 23 is moved. Turn off. In this state, the zero point of the high-sensitivity DC current clamp meter 24 is adjusted.

そして、図７の状態で、高感度直流電流クランプメータ２４のゼロ点調整を行った後に、強制接地装置２３の強制接地スイッチ２７をオンにして、直流電源装置１１から直流の探査電流を直流電源供給回路１５ｂに供給する。 Then, in the state of FIG. 7, after adjusting the zero point of the high-sensitivity DC current clamp meter 24, the forced grounding switch 27 of the forced grounding device 23 is turned on, and the DC exploration current from the DC power supply device 11 is supplied to the DC power supply. It is supplied to the supply circuit 15b.

図８は、図７の状態で高感度直流電流クランプメータのゼロ点調整を行った後に強制接地装置の強制接地スイッチをオンして探査電流を供給している状態を示す回路図である。図８に示すように、強制接地装置２３の強制接地スイッチ２７をオンすると、図６の場合と同じように、直流電源装置１１の正極から直流電源盤１３の開閉器１４ｂｐ、地絡故障点Ｆ、強制接地装置２３の強制接地スイッチ２７、強制接地装置２３の電流制限回路３１及び保護抵抗３３、健全極の作業用端子２５ｎ、直流電源装置１１の負極に至る回路が形成され直流の探査電流が流れる。探査電流は直流であることから直流電源供給回路１５ｂの電線の対地静電容量Ｃｂｐには流れない。 FIG. 8 is a circuit diagram showing a state in which the forced grounding switch of the forced grounding device is turned on and the exploration current is supplied after the zero point adjustment of the high-sensitivity DC current clamp meter is performed in the state of FIG. As shown in FIG. 8, when the forced grounding switch 27 of the forced grounding device 23 is turned on, as in the case of FIG. A circuit is formed to reach the forced grounding switch 27 of the forced grounding device 23, the current limiting circuit 31 and the protection resistor 33 of the forced grounding device 23, the working terminal 25n of the sound pole, and the negative electrode of the DC power supply device 11, and the DC exploration current is generated. It flows. Since the exploration current is direct current, it does not flow in the ground capacitance Cbp of the electric wire of the direct current power supply circuit 15b.

この状態で、高感度直流電流クランプメータ２４は、探査電流検出スイッチを操作にして、クランプした直流電源供給回路１５ｂの電線に流れる直流の探査電流を検出する。高感度直流電流クランプメータ２４をクランプした箇所は、直流電源供給回路１５ｂの分岐回路１７ｂの分岐点の手前であり地絡故障点Ｆを通りすぎた箇所であるので、図８の状態では、高感度直流電流クランプメータ２４は探査電流を検出しない。このことから、直流母線１２の近傍の電線の下流に地絡故障点Ｆがあり、直流電源供給回路１５ｂの分岐回路１７ｂの分岐点の手前の電線の下流には地絡故障点Ｆがないことが分かる。従って、この間に地絡故障点Ｆがあると判定できる。 In this state, the high-sensitivity DC current clamp meter 24 operates the exploration current detection switch to detect the DC exploration current flowing through the electric wire of the clamped DC power supply circuit 15b. The location where the high-sensitivity DC current clamp meter 24 is clamped is before the branch point of the branch circuit 17b of the DC power supply circuit 15b and has passed the ground fault failure point F. Sensitivity DC current clamp meter 24 does not detect exploration current. From this, there is a ground fault point F downstream of the electric wire near the DC bus 12, and there is no ground fault point F downstream of the electric wire before the branch point of the branch circuit 17b of the DC power supply circuit 15b. I understand. Therefore, it can be determined that there is a ground fault point F during this period.

図９は、地絡電流Ｉｆと地絡抵抗Ｒｆとのグラフである。図９では、直流電源装置１１の直流電圧Ｅが１１０Ｖであり、探査電流調整部２６の制限抵抗３０が１００ｋΩ、探査電流調整部２６の電流制限回路３１の制限電流が１．０ｍＡ及び保護抵抗３３が３３ｋΩである場合を示している。 FIG. 9 is a graph of the ground fault current If and the ground fault resistance Rf. In FIG. 9, the DC voltage E of the DC power supply device 11 is 110 V, the limiting resistance 30 of the exploration current adjusting unit 26 is 100 kΩ, the limiting current of the current limiting circuit 31 of the exploration current adjusting unit 26 is 1.0 mA, and the protection resistance 33. Is 33 kΩ.

曲線Ｃ１ａは直流電源供給回路１５の正極に地絡故障点Ｆが発生した場合、曲線Ｃ１ｂは直流電源供給回路１５の負極に地絡故障点Ｆが発生した場合に、探査電流調整部２６の制限抵抗３０を選択した際のそれぞれの地絡電流Ｉｆと地絡抵抗Ｒｆとの関係を示す曲線である。同様に、曲線Ｃ２ａは直流電源供給回路１５の正極に地絡故障点Ｆが発生した場合、曲線Ｃ２ｂは直流電源供給回路１５の負極に地絡故障点Ｆが発生した場合に、探査電流調整部２６の電流制限回路３１を選択した際の地絡電流Ｉｆと地絡抵抗Ｒｆとの関係を示す曲線である。 The curve C1a is a limitation of the exploration current adjusting unit 26 when a ground fault failure point F occurs in the positive electrode of the DC power supply circuit 15, and the curve C1b shows a ground fault failure point F in the negative electrode of the DC power supply circuit 15. It is a curve which shows the relationship between each ground fault current If and ground fault resistance Rf when resistance 30 is selected. Similarly, the curve C2a shows a ground fault failure point F in the positive electrode of the DC power supply circuit 15, and the curve C2b shows a ground fault failure point F in the negative electrode of the DC power supply circuit 15. It is a curve which shows the relationship between the ground fault current If and the ground fault resistance Rf when the current limiting circuit 31 of 26 is selected.

以下の説明では、直流電源供給回路１５の正極に地絡故障点Ｆが発生した場合の曲線Ｃ１ａ、Ｃ２ａの場合について説明する。探査電流調整部２６の制限抵抗３０を選択した場合には、曲線Ｃ１ａに示すように、地絡抵抗Ｒｆが０のときは地絡電流Ｉｆは１．１ｍＡである。これは、前述の（１）式のＥに１１０Ｖ、Ｒｆ＝０、制限抵抗＝１００ｋΩを代入して求められる。地絡抵抗Ｒｆが１５０ｋΩのときは地絡電流Ｉｆは０．４４ｍＡとなり、地絡抵抗Ｒｆが大きくなればなるほど地絡電流Ｉｆは小さくなる。 In the following description, the case of the curves C1a and C2a when the ground fault point F occurs in the positive electrode of the DC power supply circuit 15 will be described. When the limiting resistance 30 of the exploration current adjusting unit 26 is selected, as shown in the curve C1a, when the ground fault resistance Rf is 0, the ground fault current If is 1.1 mA. This is obtained by substituting 110V, Rf = 0, and limiting resistance = 100kΩ for E in the above equation (1). When the ground fault resistance Rf is 150 kΩ, the ground fault current If is 0.44 mA, and the larger the ground fault resistance Rf, the smaller the ground fault current If.

一方、探査電流調整部２６の電流制限回路３１を選択した場合には、曲線Ｃ２ａに示すように、地絡抵抗Ｒｆが０のときは地絡電流Ｉｆは１．０ｍＡである。これは、電流制限回路３１により地絡電流Ｉｆが制限電流１．０ｍＡに制限されるからである。ここで、電流制限回路３１には直列に保護抵抗３３が接続されていることから、地絡抵抗Ｒｆが７７ｋΩより大きくなると地絡電流Ｉｆは制限電流１．０ｍＡより小さくなる。 On the other hand, when the current limiting circuit 31 of the exploration current adjusting unit 26 is selected, the ground fault current If is 1.0 mA when the ground fault resistance Rf is 0, as shown in the curve C2a. This is because the ground fault current If is limited to the limiting current of 1.0 mA by the current limiting circuit 31. Here, since the protection resistor 33 is connected in series to the current limiting circuit 31, when the ground fault resistance Rf becomes larger than 77 kΩ, the ground fault current If becomes smaller than the limit current 1.0 mA.

例えば、地絡抵抗Ｒｆが５０ｋΩであるとすると、前述の（１）式のＥに１１０Ｖ、Ｒｆ＝５０、制限抵抗＝３３ｋΩを代入すると、地絡電流Ｉｆは１．３２５ｍＡとなるが、電流制限回路３１により地絡電流Ｉｆは制限電流１．０ｍＡに制限される。地絡抵抗Ｒｆが１００ｋΩであるとすると、前述の（１）式のＥに１１０Ｖ、Ｒｆ＝１００、制限抵抗＝３３ｋΩを代入すると、地絡電流Ｉｆは０．８２７ｍＡとなり、電流制限回路３１の制限電流１．０ｍＡより小さいので、地絡電流Ｉｆは０．８２７ｍＡとなる。 For example, assuming that the ground fault resistance Rf is 50 kΩ, if 110 V, Rf = 50 and the limiting resistance = 33 kΩ are substituted for E in the above equation (1), the ground fault current If is 1.325 mA, but the current limit is reached. The ground fault current If is limited by the circuit 31 to a limiting current of 1.0 mA. Assuming that the ground fault resistance Rf is 100 kΩ, if 110 V, Rf = 100, and the limiting resistance = 33 kΩ are substituted for E in the above equation (1), the ground fault current If becomes 0.827 mA, which is the limitation of the current limiting circuit 31. Since the current is smaller than 1.0 mA, the ground fault current If is 0.827 mA.

このように、探査電流調整部２６の制限抵抗３０を選択した場合には、地絡抵抗Ｒｆが大きくなればなるほど地絡電流Ｉｆは小さくなるので、直流電源供給回路１５の地絡故障点Ｆを探査する際には、探査電流調整部２６の電流制限回路３１を選択して地絡探査を行う。なお、探査電流調整部２６の電流制限回路３１を選択した際には、地絡抵抗Ｒｆが０～７７ｋΩの領域では地絡電流Ｉｆが制限電流１．０ｍＡに制限されるので、地絡電流Ｉｆから地絡抵抗Ｒｆを知ることができない。そこで、直流電源供給回路１５の地絡故障点Ｆの探査に先立ち、探査電流調整部２６の選択スイッチ３２で制限抵抗３０を選択し、強制接地装置２３の電流計２８の電流（地絡電流）を読み取り、電流の変動や大きさを確認することで故障点の様相を判別するとともに、前述したように目盛り表記部２９を参照して地絡抵抗を推定する。 In this way, when the limiting resistance 30 of the exploration current adjusting unit 26 is selected, the ground fault current If becomes smaller as the ground fault resistance Rf becomes larger, so that the ground fault failure point F of the DC power supply circuit 15 is set. When exploring, the current limiting circuit 31 of the exploration current adjusting unit 26 is selected to perform ground fault exploration. When the current limiting circuit 31 of the exploration current adjusting unit 26 is selected, the ground fault current If is limited to the limiting current of 1.0 mA in the region where the ground fault resistance Rf is 0 to 77 kΩ, so that the ground fault current If. The ground fault resistance Rf cannot be known from. Therefore, prior to the search for the ground fault point F of the DC power supply circuit 15, the limiting resistor 30 is selected by the selection switch 32 of the search current adjustment unit 26, and the current (ground fault current) of the ammeter 28 of the forced grounding device 23. By reading the above and confirming the fluctuation and magnitude of the current, the aspect of the failure point is discriminated, and as described above, the ground fault resistance is estimated with reference to the scale notation unit 29.

本発明の第１実施形態によれば、直流電源装置１１から供給される直流の探査電流の大きさを調整して出力する強制接地装置２３の探査電流調整部２６は、直流電源装置１１から供給される直流の探査電流の大きさをシーケンス回路１６が誤動作しない程度の大きさに制限する制限抵抗３０と、探査電流の大きさが予め定めた一定値になるように調整する電流制限回路３１を有するので、地絡電流の変動や大きさなど故障点の様相を判別するときは探査電流調整部２６の制限抵抗３０を選択でき、直流電源供給回路１５の地絡故障点Ｆを探査するときは探査電流調整部２６の電流制限回路３１を選択できる。 According to the first embodiment of the present invention, the exploration current adjusting unit 26 of the forced grounding device 23 that adjusts and outputs the magnitude of the exploration current of the DC supplied from the DC power supply device 11 is supplied from the DC power supply device 11. A limiting resistor 30 that limits the magnitude of the DC exploration current to the extent that the sequence circuit 16 does not malfunction, and a current limiting circuit 31 that adjusts the magnitude of the exploration current to a predetermined constant value. Therefore, the limiting resistance 30 of the exploration current adjusting unit 26 can be selected when determining the aspect of the failure point such as the fluctuation and magnitude of the ground fault current, and when searching for the ground fault point F of the DC power supply circuit 15. The current limiting circuit 31 of the exploration current adjusting unit 26 can be selected.

探査電流調整部２６の制限抵抗３０を選択したとき、地絡電流を計測する電流計２８の近傍に地絡電流に対応する地絡抵抗を表記した目盛り表記部２９を備えているので、電流計２８で測定された地絡電流から容易に地絡抵抗を推定できる。探査電流調整部２６の電流制限回路３１を選択したとき、探査電流調整部２６の電流制限回路３１から大きさが予め定めた一定値の探査電流を供給できるので、高感度直流電流クランプメータ２４により探査電流の検出を容易に行える。すなわち、高感度直流電流クランプメータ２４を用いてゼロ点調整を行いながら探査電流を検出していくので、安全にしかも高感度に地絡故障点を特定することができる。 When the limiting resistance 30 of the exploration current adjusting unit 26 is selected, the ammeter is provided with a scale notation unit 29 indicating the ground fault resistance corresponding to the ground fault current in the vicinity of the ammeter 28 for measuring the ground fault current. The ground fault resistance can be easily estimated from the ground fault current measured in No. 28. When the current limiting circuit 31 of the exploration current adjusting unit 26 is selected, the exploration current of a predetermined value can be supplied from the current limiting circuit 31 of the exploration current adjusting unit 26. The exploration current can be easily detected. That is, since the exploration current is detected while adjusting the zero point using the high-sensitivity DC current clamp meter 24, it is possible to safely and highly sensitively identify the ground fault point.

次に、本発明の第２実施形態を説明する。図１０は、本発明の第２実施形態に係る地絡故障探査装置を構成する強制接地装置及び遠隔操作器の構成図であり、図１０（ａ）は強制接地装置の構成図、図１０（ｂ）は遠隔操作器の構成図である。この第２の実施形態は、第１実施形態の地絡故障探査装置に対し、強制接地装置２３を遠隔操作する遠隔操作器３７を設けたものである。遠隔操作器３７は高感度直流電流クランプメータ２４とともに持ち運ばれる。図１と同一要素には同一符号を付し重複する説明は省略する。 Next, a second embodiment of the present invention will be described. FIG. 10 is a block diagram of a forced grounding device and a remote controller constituting the ground fault search device according to the second embodiment of the present invention, and FIG. 10A is a block diagram of the forced grounding device, FIG. 10 (a). b) is a block diagram of the remote controller. In this second embodiment, the ground fault search device of the first embodiment is provided with a remote controller 37 for remotely controlling the forced grounding device 23. The remote controller 37 is carried with the high-sensitivity DC current clamp meter 24. The same elements as those in FIG. 1 are designated by the same reference numerals, and duplicate description will be omitted.

図１０（ａ）において、図１に示した強制接地装置２３に無線通信を行う通信部３６Ａが追加して設けられ、また、図１０（ｂ）において、遠隔操作器３７に無線通信を行う通信部３６Ｂが設けられている。強制接地装置２３の通信部３６Ａと遠隔操作器３７の通信部３６Ｂとで相互にデータの送受信を行う。 In FIG. 10A, a communication unit 36A for wireless communication is additionally provided in the forced grounding device 23 shown in FIG. 1, and in FIG. 10B, communication for wireless communication is performed with the remote controller 37. A portion 36B is provided. The communication unit 36A of the forced grounding device 23 and the communication unit 36B of the remote controller 37 mutually transmit and receive data.

図１０（ｂ）に示すように、遠隔操作器３７は接地リモートスイッチ３８と切替リモートスイッチ３９と地絡電流表示器４０とを有する。遠隔操作器３７は高感度直流電流クランプメータ２４とともに持ち運ばれ、高感度直流電流クランプメータ２４で探査電流Ｉｐｆの読み取りをするための作業員により強制接地装置２３が遠隔操作される。 As shown in FIG. 10B, the remote controller 37 has a grounding remote switch 38, a switching remote switch 39, and a ground fault current indicator 40. The remote controller 37 is carried together with the high-sensitivity DC current clamp meter 24, and the forced grounding device 23 is remotely controlled by a worker for reading the exploration current Ipf with the high-sensitivity DC current clamp meter 24.

接地リモートスイッチ３８は、強制接地装置２３の強制接地スイッチ２７のオンオフを遠隔操作するスイッチであり、接地リモートスイッチ３８のオンオフ信号は遠隔操作装置３７の通信部３６Ｂを経由して強制接地装置２３の通信部３６Ａに伝達され、強制接地装置２３の強制接地スイッチ２７がオンオフ操作される。強制接地装置２３の強制接地スイッチ２７のオンオフ状態は強制接地装置２３の通信部３６Ａを経由して遠隔操作装置３７の通信部３６Ｂに伝達され状態表示器４１ａに表示出力される。これにより、高感度直流電流クランプメータ２４の作業員は遠隔操作装置３７により強制接地装置２３の強制接地スイッチ２７のオンオフをその状態を確認しながら遠隔操作し、強制接地装置２３の強制接地及びその解除を行う。 The grounding remote switch 38 is a switch that remotely controls the on / off of the forced grounding switch 27 of the forced grounding device 23, and the on / off signal of the grounding remote switch 38 is the on / off signal of the forced grounding device 23 via the communication unit 36B of the remote control device 37. It is transmitted to the communication unit 36A, and the forced grounding switch 27 of the forced grounding device 23 is turned on and off. The on / off state of the forced grounding switch 27 of the forced grounding device 23 is transmitted to the communication unit 36B of the remote control device 37 via the communication unit 36A of the forced grounding device 23, and is displayed and output to the status indicator 41a. As a result, the worker of the high-sensitivity DC current clamp meter 24 remotely controls the on / off of the forced grounding switch 27 of the forced grounding device 23 by the remote control device 37 while checking the state, and the forced grounding of the forced grounding device 23 and the forced grounding thereof. Release it.

切替リモートスイッチ３９は、強制接地装置２３の切替スイッチ３２のオンオフを遠隔操作するスイッチであり、切替リモートスイッチ３９のオンオフ信号は遠隔操作装置３７の通信部３６Ｂを経由して強制接地装置２３の通信部３６Ａに伝達され、強制接地装置２３の切替スイッチ３２がオンオフ操作される。強制接地装置２３の切替スイッチ３２のオンオフ状態は強制接地装置２３の通信部３６Ａを経由して遠隔操作装置３７の通信部３６Ｂに伝達され状態表示器４１ｂに表示出力される。これにより、高感度直流電流クランプメータ２４の作業員は遠隔操作装置３７により強制接地装置２３の切替スイッチ３２のオンオフをその状態を確認しながら遠隔操作し、制限抵抗３０と電流制限回路３１との切替を遠隔操作で行う。 The changeover remote switch 39 is a switch for remotely controlling the on / off of the changeover switch 32 of the forced grounding device 23, and the on / off signal of the changeover remote switch 39 is the communication of the forced grounding device 23 via the communication unit 36B of the remote control device 37. It is transmitted to the unit 36A, and the changeover switch 32 of the forced grounding device 23 is turned on and off. The on / off state of the changeover switch 32 of the forced grounding device 23 is transmitted to the communication unit 36B of the remote control device 37 via the communication unit 36A of the forced grounding device 23, and is displayed and output to the status indicator 41b. As a result, the worker of the high-sensitivity DC current clamp meter 24 remotely controls the on / off of the changeover switch 32 of the forced grounding device 23 by the remote control device 37 while checking the state, and the limiting resistance 30 and the current limiting circuit 31 are combined. Switching is performed by remote control.

地絡電流表示器４０は、強制接地装置２３の電流計２８で測定された地絡電流を表示するもので強制接地装置２３の電流計２８と同等の機能を持つ。強制接地装置２３の電流計２８で測定された地絡電流は、強制接地装置２３の通信部３６Ａを経由して遠隔操作装置３７の通信部３６Ｂに伝達され地絡電流表示器４０に表示出力される。地絡電流表示器４０は、強制接地装置２３の電流計２８で測定された地絡電流及び地絡抵抗値をアナログ表示してもよいしディジタル表示をしてもよい。 The ground fault current indicator 40 displays the ground fault current measured by the ammeter 28 of the forced grounding device 23, and has the same function as the ammeter 28 of the forced grounding device 23. The ground fault current measured by the ammeter 28 of the forced grounding device 23 is transmitted to the communication unit 36B of the remote control device 37 via the communication unit 36A of the forced grounding device 23, and is displayed and output to the ground fault current indicator 40. To. The ground fault current indicator 40 may display the ground fault current and the ground fault resistance value measured by the ammeter 28 of the forced grounding device 23 in analog or digital display.

本発明の第２実施形態によれば、第１実施形態の効果に加え、高感度直流電流クランプメータ２４とともに持ち運ばれる遠隔操作器３７にて、強制接地装置２３の強制接地スイッチ２７をオンにして強制接地したり、強制接地装置２３の切替スイッチ３２のオンオフにより探査電流調整部２６の制限抵抗３０と電流制限器３１との切り替えを遠隔操作で行えるので、強制接地装置２３を操作する作業員が不要となる。また、遠隔操作器３７にて、強制接地装置２３の電流計２８で検出した地絡電流を読み取ることができるので、地絡電流と探査電流との突き合わせが容易に行え、複数の箇所で地絡故障が発生していることを容易に判定できる。すなわち、高感度直流電流クランプメータ２４で検出した探査電流と強制接地装置２３の電流計２８で検出した地絡電流とが等しいときは地絡故障点は１箇所であるが、地絡電流が探査電流より大きいときは複数箇所で地絡していることが分かる。 According to the second embodiment of the present invention, in addition to the effect of the first embodiment, the forced grounding switch 27 of the forced grounding device 23 is turned on by the remote controller 37 carried together with the high-sensitivity DC current clamp meter 24. The worker who operates the forced grounding device 23 can remotely switch between the limiting resistance 30 of the exploration current adjusting unit 26 and the current limiting device 31 by turning the changeover switch 32 of the forced grounding device 23 on and off. Is unnecessary. Further, since the remote controller 37 can read the ground fault current detected by the ammeter 28 of the forced grounding device 23, the ground fault current and the exploration current can be easily matched with each other, and the ground fault can be easily matched at a plurality of points. It can be easily determined that a failure has occurred. That is, when the exploration current detected by the high-sensitivity DC current clamp meter 24 and the ground fault current detected by the ammeter 28 of the forced grounding device 23 are equal, there is one ground fault failure point, but the ground fault current is searched. When it is larger than the current, it can be seen that there are ground faults at multiple points.

次に、本発明の第３実施形態を説明する。図１１は、本発明の第３実施形態に係る地絡故障探査装置を構成するクランプメータアダプタ４２の構成図である。本発明の第３実施形態は、第２実施形態に対しクランプメータアダプタ４２を追加して設けたものであり、高感度直流電流クランプメータ２４を操作する作業員により持ち運ばれ、高感度直流電流クランプメータ２４に接続して使用される。 Next, a third embodiment of the present invention will be described. FIG. 11 is a configuration diagram of a clamp meter adapter 42 constituting the ground fault search device according to the third embodiment of the present invention. The third embodiment of the present invention is provided by adding the clamp meter adapter 42 to the second embodiment, and is carried by a worker who operates the high-sensitivity direct current clamp meter 24, and has a high-sensitivity direct current. It is used by connecting to the clamp meter 24.

クランプメータアダプタ４２は、高感度直流電流クランプメータ２４で検出された探査電流の電流値を表示出力するものであり、探査電流が変動する場合であっても安定して探査電流を読み取れるように電流値を表示出力するものである。これは、前述したように高感度直流電流クランプメータ２４には測定した電流を表示する電流表示を有しているが、数Ｈｚ程度の長周期の電圧変動が直流電源供給回路１５に重畳して地絡電流が脈動した場合には、高感度直流電流クランプメータ２４で検出される探査電流も変動し、探査電流を安定して読み取ることが難しくなるからである。そこで、クランプメータアダプタ４２は、高感度直流電流クランプメータ２４で検出された所定期間の探査電流の移動平均電流値を演算する移動平均演算部４３を有している。 The clamp meter adapter 42 displays and outputs the current value of the exploration current detected by the high-sensitivity DC current clamp meter 24, and is a current so that the exploration current can be read stably even when the exploration current fluctuates. The value is displayed and output. As described above, the high-sensitivity DC current clamp meter 24 has a current display that displays the measured current, but a long-period voltage fluctuation of about several Hz is superimposed on the DC power supply circuit 15. This is because when the ground fault current pulsates, the exploration current detected by the high-sensitivity DC current clamp meter 24 also fluctuates, making it difficult to read the exploration current in a stable manner. Therefore, the clamp meter adapter 42 has a moving average calculation unit 43 that calculates a moving average current value of the exploration current detected by the high-sensitivity DC current clamp meter 24 for a predetermined period.

図１１において、高感度直流電流クランプメータ２４で検出された探査電流は入力処理部４４に入力され、入力処理部４４で移動平均演算部４３及び表示処理演算部４５で処理できる信号に変換されて記憶部４６に記憶される。 In FIG. 11, the exploration current detected by the high-sensitivity DC current clamp meter 24 is input to the input processing unit 44, and is converted into a signal that can be processed by the moving average calculation unit 43 and the display processing calculation unit 45 by the input processing unit 44. It is stored in the storage unit 46.

移動平均演算部４３は、移動平均演算選択スイッチ４７により移動平均演算のセットまたはリセットが選択される。移動平均演算選択スイッチ４７により移動平均演算のセットが選択されたときは、移動平均演算部４３は、所定期間設定部４８に設定された所定期間の探査電流の移動平均電流値を演算する。所定期間設定部４８には入力装置４９から所定期間が設定される。所定期間は、例えば１ｓ、１０ｓ、６０ｓなどであり、長周期の電圧変動に合わせて設定される。移動平均演算部４３で演算された探査電流の移動平均値は、表示処理演算部４５を介して探査電流表示器５０に出力される。表示処理演算部４５は探査電流の移動平均値をアナログ表示またはディジタル表示に変換して探査電流表示器５０に出力する。 In the moving average calculation unit 43, the set or reset of the moving average calculation is selected by the moving average calculation selection switch 47. When the set of moving average calculation is selected by the moving average calculation selection switch 47, the moving average calculation unit 43 calculates the moving average current value of the exploration current for the predetermined period set in the predetermined period setting unit 48. A predetermined period is set in the predetermined period setting unit 48 from the input device 49. The predetermined period is, for example, 1s, 10s, 60s, etc., and is set according to the voltage fluctuation in a long period. The moving average value of the exploration current calculated by the moving average calculation unit 43 is output to the exploration current display 50 via the display processing calculation unit 45. The display processing calculation unit 45 converts the moving average value of the exploration current into an analog display or a digital display and outputs it to the exploration current display 50.

一方、移動平均演算選択スイッチ４７により移動平均演算のリセットが選択されたときは、表示処理演算部４５は記憶部４６に記憶された探査電流を読み込み、探査電流の値をアナログ表示またはディジタル表示に変換して探査電流表示器５０に出力する。 On the other hand, when the reset of the moving average calculation is selected by the moving average calculation selection switch 47, the display processing calculation unit 45 reads the exploration current stored in the storage unit 46 and displays the value of the exploration current in analog display or digital display. It is converted and output to the exploration current indicator 50.

発明の第３実施形態によれば、第１実施形態及び第２実施形態の効果に加え、高感度直流電流クランプメータ２４に接続されるクランプメータアダプタ４２にて、所定期間の探査電流の移動平均演算のセットまたはリセットの選択を可能としているので、数Ｈｚ程度の長周期の電圧変動が直流電源供給回路１５に重畳し地絡電流が脈動した場合であっても、探査電流の移動平均値を探査電流表示器５０に表示させることによって、容易に安定して探査電流を読み取れる。 According to the third embodiment of the present invention, in addition to the effects of the first embodiment and the second embodiment, the moving average of the exploration current for a predetermined period by the clamp meter adapter 42 connected to the high-sensitivity DC current clamp meter 24. Since it is possible to select the set or reset of the calculation, even if a long-period voltage fluctuation of about several Hz is superimposed on the DC power supply circuit 15 and the ground fault current pulsates, the moving average value of the exploration current can be obtained. By displaying the exploration current on the exploration current indicator 50, the exploration current can be easily and stably read.

以上、本発明のいくつかの実施形態を説明したが、これらの実施形態は、例として提示したものであり、発明の範囲を限定することは意図していない。これら新規な実施形態は、その他の様々な形態で実施されることが可能であり、発明の要旨を逸脱しない範囲で、種々の省略、置き換え、変更を行うことができる。これら実施形態やその変形は、発明の範囲や要旨に含まれるとともに、特許請求の範囲に記載された発明とその均等の範囲に含まれる。 Although some embodiments of the present invention have been described above, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other embodiments, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments and variations thereof are included in the scope and gist of the invention, and are also included in the scope of the invention described in the claims and the equivalent scope thereof.

１１…直流電源装置
１２…直流母線
１３…直流電源盤
１４…開閉器
１５…直流電源供給回路
１６…シーケンス回路
１７…分岐回路
１８…分圧回路
１９…直流地絡継電器
２０…低周波交流電源装置
２１…交流電流クランプメータ
２２…フリッカ装置
２３…強制接地装置
２４…高感度直流電流クランプメータ
２５…作業用端子
２６…探査電流調整部
２７…強制接地スイッチ
２８…電流計
２９…目盛り表記部
２９Ａ…地絡電流目盛り部
２９Ｂ…地絡抵抗目盛り部
３０…制限抵抗
３１…電流制限回路
３２…切替スイッチ
３３…保護抵抗
３４…定電流ダイオード
３５…ダイオードブリッジ回路
３６…通信部
３７…遠隔操作器
３８…接地リモートスイッチ
３９…切替リモートスイッチ
４０…地絡電流表示器
４１…状態表示器
４２…クランプアダプタ
４３…移動平均演算部
４４…入力処理部
４５…表示処理演算部
４６…記憶部
４７…移動平均演算選択スイッチ
４８…所定期間設定部
４９…入力装置
５０…探査電流表示器 11 ... DC power supply device 12 ... DC bus 13 ... DC power supply panel 14 ... Switch 15 ... DC power supply circuit 16 ... Sequence circuit 17 ... Branch circuit 18 ... Voltage division circuit 19 ... DC ground fault relay 20 ... Low frequency AC power supply device 21 ... AC current clamp meter 22 ... Flicker device 23 ... Forced grounding device 24 ... High-sensitivity DC current clamp meter 25 ... Working terminal 26 ... Exploration current adjustment unit 27 ... Forced grounding switch 28 ... Current meter 29 ... Scale notation unit 29A ... Ground fault current scale 29B ... Ground fault resistance scale 30 ... Limiting resistance 31 ... Current limiting circuit 32 ... Changeover switch 33 ... Protection resistance 34 ... Constant current diode 35 ... Diode bridge circuit 36 ... Communication unit 37 ... Remote controller 38 ... Grounding remote switch 39 ... Switching remote switch 40 ... Ground fault current indicator 41 ... Status indicator 42 ... Clamp adapter 43 ... Moving average calculation unit 44 ... Input processing unit 45 ... Display processing calculation unit 46 ... Storage unit 47 ... Moving average calculation Selection switch 48 ... Predetermined period setting unit 49 ... Input device 50 ... Exploration current indicator

Claims (5)

電気所の電気機器を操作するシーケンス回路に直流電源装置から直流電源を供給する複数の直流電源供給回路のいずれかに地絡故障が発生したとき、前記直流電源供給回路の電線にクランプされゼロ点調整を行ってから前記直流電源装置から供給される直流の探査電流を高感度直流電流クランプメータにより検出して前記地絡故障点を探査する際に、前記地絡故障を検出する直流地絡継電器が接続された前記直流電源供給回路の直流母線の正極と負極との間の分圧回路の分圧中点を非接地とした状態で用いられる強制接地装置であり、
前記地絡故障が発生した前記直流電源供給回路の前記直流母線への接続点における作業用の正極及び負極の作業用端子のうち健全極の作業用端子に接続され、前記直流電源装置から供給される直流の探査電流の大きさを調整して出力する探査電流調整部と、
前記探査電流調整部に直列に接続され前記高感度直流電流クランプメータのゼロ点調整のときはオフして前記直流電源装置から供給される直流の探査電流の大きさを前記シーケンス回路が誤動作しない程度の大きさに制限する制限抵抗を非接地とし、前記高感度直流電流クランプメータが前記地絡故障点を探査するときはオンして前記探査電流調整部を接地し前記直流電源装置から直流の探査電流を前記直流電源供給回路に供給するための強制接地スイッチと、
前記強制接地スイッチに直列接続され前記強制接地スイッチに流れる電流を測定する電流計を備え、
前記探査電流調整部は、前記制限抵抗と、前記制限抵抗に並列に接続され前記探査電流の大きさが予め定めた一定値になるように調整する電流制限回路と、前記制限抵抗と前記電流制限回路とを切り替える切替スイッチとを有したことを特徴とする強制接地装置。 When a ground fault occurs in any of the multiple DC power supply circuits that supply DC power from the DC power supply to the sequence circuit that operates the electrical equipment of the electric station, it is clamped to the electric wire of the DC power supply circuit and the zero point. A DC ground fault relay that detects the ground fault when searching for the ground fault point by detecting the DC exploration current supplied from the DC power supply device with a high-sensitivity DC current clamp meter after making adjustments. It is a forced grounding device used in a state where the midpoint of the voltage dividing circuit between the positive and negative sides of the DC bus of the DC power supply circuit to which is connected is not grounded.
It is connected to the work terminal of the sound electrode among the work terminals of the positive electrode and the negative electrode for work at the connection point of the DC power supply circuit to the DC bus where the ground fault has occurred, and is supplied from the DC power supply device. The exploration current adjustment unit that adjusts and outputs the magnitude of the DC exploration current,
When the zero point adjustment of the high-sensitivity DC current clamp meter is connected in series with the exploration current adjustment unit, it is turned off to the extent that the sequence circuit does not malfunction the magnitude of the DC exploration current supplied from the DC power supply device. The limiting resistance that limits the size of the current is not grounded, and when the high-sensitivity DC current clamp meter searches for the ground fault point, it is turned on to ground the search current adjustment unit and search for DC from the DC power supply. A forced grounding switch for supplying current to the DC power supply circuit ,
It is equipped with an ammeter that is connected in series to the forced ground switch and measures the current flowing through the forced ground switch.
The exploration current adjusting unit includes the limiting resistance , a current limiting circuit connected in parallel with the limiting resistance and adjusting the magnitude of the exploration current to a predetermined constant value, and the limiting resistance and the current limiting. A forced grounding device characterized by having a changeover switch for switching between circuits. 前記電流計の近傍に地絡電流に対応する地絡抵抗を表記した目盛り表記部を備えたことを特徴とする請求項１記載の強制接地装置。 The forced grounding device according to claim 1, further comprising a scale notation portion indicating the ground fault resistance corresponding to the ground fault current in the vicinity of the ammeter. 請求項１または請求項２に記載のいずれかの強制接地装置と、
前記直流電源供給回路の電線にクランプされゼロ点調整を行ってから前記直流電源装置から供給される直流の探査電流を検出する高感度直流電流クランプメータとを備えたことを特徴とする地絡故障探査装置。 With any of the forced grounding devices according to claim 1 or 2.
A ground fault failure characterized by being equipped with a high-sensitivity DC current clamp meter that detects the DC exploration current supplied from the DC power supply device after being clamped to the electric wire of the DC power supply circuit and adjusting the zero point. Exploration equipment. 前記強制接地装置の前記強制接地スイッチのオンオフを遠隔操作する接地リモートスイッチと、前記強制接地装置における前記探査電流調整部の前記切替スイッチの切替操作を遠隔操作する切替リモートスイッチと、前記強制接地装置の前記電流計で測定された地絡電流を前記強制接地装置の前記電流計と同等に表示する地絡電流表示器とを有し、前記高感度直流電流クランプメータとともに持ち運ばれる遠隔操作器を備えたことを特徴とする請求項３に記載の地絡故障探査装置。 A grounding remote switch that remotely controls the on / off of the forced grounding switch of the forced grounding device, a switching remote switch that remotely controls the switching operation of the changeover switch of the search current adjusting unit in the forced grounding device, and the forced grounding device. A remote controller that has a ground fault current indicator that displays the ground fault current measured by the current meter in the same manner as the current meter of the forced grounding device, and is carried together with the high-sensitivity DC current clamp meter. The ground fault search device according to claim 3, wherein the device is provided. 前記高感度直流電流クランプメータに接続され前記高感度直流電流クランプメータで検出された所定期間の探査電流の移動平均電流値を演算する移動平均演算部と、前記移動平均演算部で演算する移動平均電流値の所定期間を設定する所定期間設定部と、前記移動平均演算部の演算のセットまたはリセットを選択する移動平均演算選択スイッチと、前記移動平均演算部で演算された移動平均電流値または前記高感度直流電流クランプメータで検出された電流値を表示出力する探査電流表示器とを有したクランプメータアダプタを備えたことを特徴とする請求項３または請求項４に記載の地絡故障探査装置。 A moving average calculation unit that is connected to the high-sensitivity DC current clamp meter and calculates a moving average current value of the exploration current for a predetermined period detected by the high-sensitivity DC current clamp meter, and a moving average calculated by the moving average calculation unit. A predetermined period setting unit for setting a predetermined period of the current value, a moving average calculation selection switch for selecting a set or reset of the calculation of the moving average calculation unit, and a moving average current value calculated by the moving average calculation unit or the above. The ground fault search device according to claim 3 or 4, further comprising a clamp meter adapter including a search current indicator that displays and outputs a current value detected by a high-sensitivity DC current clamp meter. ..
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