JP6541485B2 - Station building auxiliary power source ground fault detection device - Google Patents

Station building auxiliary power source ground fault detection device Download PDF

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JP6541485B2
JP6541485B2 JP2015141330A JP2015141330A JP6541485B2 JP 6541485 B2 JP6541485 B2 JP 6541485B2 JP 2015141330 A JP2015141330 A JP 2015141330A JP 2015141330 A JP2015141330 A JP 2015141330A JP 6541485 B2 JP6541485 B2 JP 6541485B2
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ground fault
ground
power supply
supply line
voltage
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JP2017020996A (en
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孝雄 西川
孝雄 西川
田中　憲
憲 田中
敬雄 大久保
敬雄 大久保
川原　敬治
敬治 川原
和彦 伊東
和彦 伊東
隆 山野井
隆 山野井
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Mitsubishi Electric Corp
West Japan Railway Co
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West Japan Railway Co
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    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B10/00—Integration of renewable energy sources in buildings
    • Y02B10/10—Photovoltaic [PV]
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/50—Photovoltaic [PV] energy

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  • Measurement Of Resistance Or Impedance (AREA)
  • Photovoltaic Devices (AREA)

Description

本発明は、トランスレスで駅舎内電路系統に接続されるパワーコンディショナと太陽電池との間の地絡を検出する駅舎補助電源用地絡検出装置に関するものである。   The present invention relates to a ground fault detection device for a station auxiliary power source that detects a ground fault between a solar battery and a power conditioner connected to a station electrical circuit system without a transformer.

近年、鉄道の駅舎設備への電力供給に、太陽光発電システムを用いた補助電源装置を設ける場合が多くなっている。パワーコンディショナと太陽電池との間の地絡事故は一般的にパワーコンディショナに設けられる地絡検出装置にて保護する。地絡検出装置が検出する電流レベルは、太陽電池の発電電力に応じて規格により上限が規定されている。そのため、非接地回路にて、規格の上限より感度の高い、数ｍＡレベルの地絡電流を検出できる地絡検出システムの設置が求められている。例えば、特許文献１には、地絡事故により絶縁抵抗の値が低下する前に直流回路の地絡を検出するため、直流回路を構成する正極側電源線と対地間、または直流回路を構成する負極側電源線と対地間に地絡抵抗を接続し、正極側電源線と対地が接続されたときに地絡抵抗の両端で発生した電圧と、負極側電源線と対地が接続されたときに地絡抵抗の両端で発生した電圧とを検出し、検出された電圧に基づいて対地絶縁抵抗の抵抗値を算出し、算出した差電圧が設定電圧値を超えたとき、地絡が発生していると判定する構成が開示されている。   In recent years, in many cases, an auxiliary power supply using a solar power generation system is provided to supply power to railway station facilities. A ground fault between the power conditioner and the solar cell is generally protected by a ground fault detection device provided in the power conditioner. The upper limit of the current level detected by the ground fault detection device is defined by the standard according to the power generated by the solar cell. Therefore, installation of a ground fault detection system capable of detecting a ground fault current of several mA level, which is higher in sensitivity than the upper limit of the standard, is required in the ungrounded circuit. For example, in Patent Document 1, in order to detect a ground fault in a direct current circuit before the value of insulation resistance decreases due to a ground fault, a positive polarity side power supply line constituting the direct current circuit and a ground circuit or a direct current circuit is configured. A ground resistance is connected between the negative power supply line and the ground, and the voltage generated at both ends of the ground resistance when the positive power supply line is connected to the ground, and when the negative power supply line is connected to the ground The voltage generated at both ends of the ground fault resistance is detected, the resistance value of the ground insulation resistance is calculated based on the detected voltage, and when the calculated differential voltage exceeds the set voltage value, a ground fault occurs. There is disclosed a configuration for determining that there is.

特開２０１３−２１０２４６号公報JP, 2013-210246, A

特許文献１に示す構成を駅舎補助電源用の太陽光発電システムの直流回路に使用する場合、次のような問題があった。太陽光発電システムは、太陽電池から供給された直流電圧をパワーコンディショナに入力し、単相３線式の交流に変換して駅舎内電路系統に出力している。駅舎内電路系統は、駅舎内に設置された負荷、例えば、照明およびエレベーターに電力を供給するように構成されている。ここでパワーコンディショナがトランスレス方式のパワーコンディショナである場合、このような直流電圧から交流電圧への変換では、直流回路を構成する正極側電源線と負極側電源線に対して、接地極の電圧を変化させて中性線に対する正極側電源線および負極側電源線の各々の電圧を、見かけ上交流となるようにしている。また、トランスレス方式のパワーコンディショナでは、パワーコンディショナの直流側がパワーコンディショナの交流側と絶縁されていないため、接地極は駅舎内電路系統を介して大地に接続されている。そのためパワーコンディショナが駅舎内電路系統と連系している状態では、抵抗値算出装置が対地絶縁抵抗の算出に用いるための、正極側電源線と対地間の電位または負極側電源線と対地間の電位が常に変動し、絶縁抵抗の算出が困難であり、地絡を検出できない虞がある。   When using the structure shown to patent document 1 for the direct current circuit of the solar energy power generation system for station building auxiliary power supplies, there existed the following problems. The solar power generation system inputs a DC voltage supplied from a solar cell into a power conditioner, converts the DC voltage into a single-phase three-wire AC, and outputs the AC to a station electrical circuit system. The station electric circuit system is configured to supply power to loads installed in the station, such as lighting and elevators. Here, in the case where the power conditioner is a transformerless type power conditioner, in such conversion from direct current voltage to alternating current voltage, the ground pole with respect to the positive side power supply line and the negative side power supply line constituting the direct current circuit. The voltage of each of the positive side power supply line and the negative side power supply line with respect to the neutral wire is made to be alternating current in appearance. Further, in the transformerless type power conditioner, the ground pole is connected to the ground through the electrical circuit system in the station because the DC side of the power conditioner is not insulated from the AC side of the power conditioner. Therefore, when the power conditioner is connected to the station electrical circuit system, the positive side power line and the ground potential or the negative side power line and the ground line for the resistance value calculation device to use for calculation of the ground insulation resistance. The potential of the sensor constantly fluctuates, which makes it difficult to calculate the insulation resistance, and there is a possibility that a ground fault can not be detected.

本発明は、上記に鑑みてなされたものであって、トランスレスで駅舎内電路系統に接続されるパワーコンディショナが駅舎内電路系統と解列状態であるか連系状態であるかに係わらずパワーコンディショナと太陽電池との間に設けられる直流回路の地絡を精度良く検出可能な駅舎補助電源用地絡検出装置を得ることを目的とする。   The present invention has been made in view of the above, and the power conditioner connected to the station electric line system without transformer is in a disconnection state or an interconnection state with the station electric line system regardless of whether it is transformerless. It is an object of the present invention to provide a station building auxiliary power source ground fault detection device capable of accurately detecting a ground fault of a direct current circuit provided between a power conditioner and a solar cell.

上述した課題を解決し、目的を達成するために、本発明は、太陽電池と、前記太陽電池からの電力を駅舎内電路系統へ供給し、前記駅舎内電路系統とトランスレスで接続されるパワーコンディショナと、前記太陽電池から出力される電力をパワーコンディショナへ供給する直流回路と、前記パワーコンディショナと前記太陽電池との間に設けられる直流回路の地絡を検出する駅舎補助電源用地絡検出装置とを備えた地絡検出システムにおいて用いられる駅舎補助電源用地絡検出装置であって、前記駅舎補助電源用地絡検出装置は、前記直流回路の正極側電源線と前記直流回路の負極側電源線との間で検出された第１の電圧検出値と、前記正極側電源線と対地間または前記負極側電源線と対地間の第２の電圧検出値と、前記正極側電源線と前記負極側電源線との間に流れる不平衡電流の電流検出値と、を入力として、前記パワーコンディショナが前記駅舎内電路系統と解列状態にあるときに前記直流回路に発生した地絡と、前記パワーコンディショナが前記駅舎内電路系統と連系状態にあるときに前記直流回路に発生した地絡とを検出する地絡検出部を備え、前記地絡検出部は、前記第１の電圧検出値と前記第２の電圧検出値とに基づいて前記パワーコンディショナが前記駅舎内電路系統と解列状態にあるか連系状態にあるかを判定する連系状態判定部と、前記第１の電圧検出値と前記第２の電圧検出値とに基づいて前記直流回路に発生した地絡を検出する第１の地絡検出部と、前記電流検出値に基づいて前記直流回路に発生した地絡を検出する第２の地絡検出部と、を備えたことを特徴とする。 In order to solve the problems described above and to achieve the object, the present invention supplies a solar cell and power from the solar cell to a station electrical circuit system, and power connected with the station electrical circuit system without transformer. A ground fault for a station auxiliary power source for detecting a ground fault in a DC circuit provided between the power conditioner and the solar cell, a DC circuit for supplying a power conditioner with the power output from the solar cell, and a solar cell The station building auxiliary power ground fault detection apparatus for use in a ground fault detection system comprising a detection apparatus, wherein the station building auxiliary power ground fault detecting apparatus comprises a positive power supply line of the DC circuit and a negative power supply of the DC circuit. A second voltage detection value between the positive power supply line and the ground or between the negative power supply line and the ground, and the positive power supply line and the second voltage detection value detected between the positive and negative lines; A ground fault generated in the DC circuit when the power conditioner is in a disconnection state with the electric circuit system in the station building, with the current detection value of the unbalanced current flowing between the pole side power supply line and the input. A ground fault detection unit for detecting a ground fault generated in the DC circuit when the power conditioner is in an interconnection state with the electric line system in the station building, the ground fault detection unit includes the first voltage detection. An interconnection state determination unit that determines whether the power conditioner is in a disconnection state or an interconnection state with the station electrical circuit system based on a value and the second voltage detection value; A first ground fault detection unit for detecting a ground fault generated in the DC circuit based on a voltage detection value and the second voltage detection value, and a ground fault generated in the DC circuit based on the current detection value a second earth fault detection unit for detecting, by comprising And butterflies.

この発明によれば、トランスレスで駅舎内電路系統に接続されるパワーコンディショナが駅舎内電路系統と解列状態であるか連系状態であるかに係わらずパワーコンディショナと駅舎補助電源用の太陽電池との間に設けられる直流回路の地絡を精度良く検出可能、という効果を奏する。   According to the present invention, the power conditioner connected to the station electric line system without transformer is in a disconnection state or in an interconnection state with the station electric line system for the power conditioner and the station auxiliary power supply The ground fault of the direct current circuit provided between the solar cells can be detected with high accuracy.

実施の形態１に係る地絡検出システムの構成図Configuration diagram of the ground fault detection system according to the first embodiment 実施の形態１に係る地絡検出システムのパワーコンディショナが駅舎内電路系統と解列状態であるときに正極側電源線に地絡抵抗を接続した状態を示す図The figure which shows the state which connected the ground fault resistance to the positive electrode side power supply line, when the power conditioner of the ground fault detection system which concerns on Embodiment 1 is a disconnection state with the electric line system in a station building. 実施の形態１に係る地絡検出システムのパワーコンディショナが駅舎内電路系統と解列状態であるときに負極側電源線に地絡抵抗を接続した状態を示す図The figure which shows the state which connected the ground fault resistance to the negative electrode side power supply line, when the power conditioner of the ground fault detection system which concerns on Embodiment 1 is a disconnection state with the electric line system in a station building. 実施の形態１に係る地絡検出システムのパワーコンディショナが駅舎内電路系統と連系状態である場合に正極側電源線に地絡が発生したときに流れる地絡電流の経路を表す図A diagram showing a path of a ground fault current which flows when a ground fault occurs in the positive electrode side power supply line when the power conditioner of the ground fault detection system according to the first embodiment is in an interconnection state with the station electrical circuit system. 実施の形態１に係る地絡検出システムのパワーコンディショナが駅舎内電路系統と連系状態である場合に負極側電源線に地絡が発生したときに流れる地絡電流の経路を表す図A diagram showing a path of a ground fault current which flows when a ground fault occurs in the negative electrode side power supply line when the power conditioner of the ground fault detection system according to the first embodiment is in an interconnection state with the station electrical circuit system. 実施の形態１に係る駅舎補助電源用地絡検出装置の地絡検出部が実行する処理のフローチャートFlow chart of processing executed by the ground fault detection unit of the station building auxiliary power ground fault detection device according to the first embodiment 実施の形態２に係る地絡検出システムの構成図Configuration diagram of a ground fault detection system according to a second embodiment 実施の形態２に係る地絡検出システムのパワーコンディショナが駅舎内電路系統と解列状態である場合に負極側電源線に電流検出用地絡抵抗を接続したときに流れる地絡電流の経路を表す状態を表す図When the power conditioner of the ground fault detection system according to the second embodiment is in a disconnection state with the electric line system in the station building, it represents the path of the ground fault current that flows when the ground fault resistance for current detection is connected to the negative power supply line. Diagram showing the state 実施の形態２に係る地絡検出システムのパワーコンディショナが駅舎内電路系統と解列状態である場合に正極側電源線に電流検出用地絡抵抗を接続したときに流れる地絡電流の経路を表す状態を表す図When the power conditioner of the ground fault detection system according to the second embodiment is in the disconnection state with the station electrical circuit system, it represents the path of the ground fault current that flows when the current detection ground fault resistor is connected to the positive power supply line. Diagram showing the state 実施の形態２に係る駅舎補助電源用地絡検出装置の地絡検出部が実行する処理のフローチャートFlow chart of processing performed by the ground fault detection unit of the station building auxiliary power ground fault detection device according to the second embodiment

以下に、本発明に係る地絡検出システムの実施の形態を図面に基づいて詳細に説明する。なお、この実施の形態によりこの発明が限定されるものではない。   Hereinafter, an embodiment of a ground fault detection system according to the present invention will be described in detail based on the drawings. The present invention is not limited by the embodiment.

実施の形態１．
図１は実施の形態１に係る地絡検出システム１００を示したものである。地絡検出システム１００は、太陽光の照度に応じた直流電力を発生する直流電源である太陽電池１と、駅舎内電路系統とトランスレスで接続されるとともに太陽電池１から供給された直流電力を交流電力に変換して駅舎内電路系統へ出力するパワーコンディショナ２と、太陽電池１から出力される直流電力をパワーコンディショナ２へ供給する直流配電用の直流回路３と、直流回路３に発生した地絡を検出する駅舎補助電源用地絡検出装置４とを備える。また、太陽電池１とパワーコンディショナ２により駅舎に電力を供給する太陽電池システムを構成している。以下では駅舎補助電源用地絡検出装置を単に地絡検出装置と称する。 Embodiment 1
FIG. 1 shows a ground fault detection system 100 according to a first embodiment. The ground fault detection system 100 is connected to the solar cell 1, which is a DC power supply that generates DC power according to the illuminance of sunlight, without transformers in the station electrical circuit system, and is supplied with DC power supplied from the solar cell 1 Power conditioner 2 that converts AC power and outputs it to station electrical circuit, DC circuit 3 for DC power distribution that supplies DC power output from solar cell 1 to power conditioner 2, and DC circuit 3 And a station building auxiliary power source ground fault detection device 4 for detecting the ground fault. Further, a solar cell system for supplying power to a station building by the solar cell 1 and the power conditioner 2 is configured. Hereinafter, the station building auxiliary power source ground fault detection device is simply referred to as a ground fault detection device.

パワーコンディショナ２は、太陽電池１から供給された直流電力を駅舎内電路系統の周波数の交流電力に変換するインバータ回路２１と、インバータ回路２１の出力側と駅舎内電路系統５とを解列状態または連系状態にする連系リレー２２とを有する。直流回路３は、太陽電池１の正極側電圧が印加される直流給電母線である正極側電源線３１と、太陽電池１の負極側電圧が印加される直流給電母線である負極側電源線３２とを有する。直流回路３では、正極側電源線３１と対地間に対地絶縁抵抗３３が存在し、負極側電源線３２と対地間に対地絶縁抵抗３４が存在する。解列状態とは連系リレー２２が開放された状態であり、連系状態とは連系リレー２２が投入された状態である。   The power conditioner 2 disconnects the inverter circuit 21 for converting the DC power supplied from the solar cell 1 into AC power of the frequency of the station electrical circuit, the output side of the inverter circuit 21 and the station electrical circuit 5 disconnected. Or an interconnection relay 22 in an interconnection state. The DC circuit 3 includes a positive power supply line 31 which is a DC power supply bus to which a positive voltage of the solar cell 1 is applied, and a negative power supply line 32 which is a DC power supply bus to which a negative voltage of the solar cell 1 is applied. Have. In the DC circuit 3, a ground insulation resistance 33 exists between the positive power supply line 31 and the ground, and a ground insulation resistance 34 exists between the negative power supply line 32 and the ground. The disconnection state is a state in which the interconnection relay 22 is opened, and the interconnection state is a state in which the interconnection relay 22 is turned on.

対地絶縁抵抗３３の抵抗値をＲｐとした場合、Ｒｐには、非地絡時の対地絶縁抵抗３５と地絡発生時の対地絶縁抵抗３６が存在する。以下の説明では、対地絶縁抵抗３５の抵抗値はＲｐ０とし、対地絶縁抵抗３６の抵抗値はＲｐ１とする。 When the resistance value of the ground insulation resistance 33 and R p, the R p, ground insulation resistance 36 during ground insulation resistance 35 and ground fault occurs in the non-ground fault exists. In the following description, the resistance value of the ground insulation resistance 35 is R p0, and the resistance value of the ground insulation resistance 36 is R p1 .

対地絶縁抵抗３４の抵抗値をＲｎとした場合、Ｒｎには、非地絡時の対地絶縁抵抗３７と地絡発生時の対地絶縁抵抗３８が存在する。以下の説明では、対地絶縁抵抗３７の抵抗値をＲｎ０とし、対地絶縁抵抗３８の抵抗値をＲｎ１とする。 When the resistance value of the ground insulation resistance 34 and R n, the R n, ground insulation resistance 38 during ground insulation resistance 37 and ground fault occurs in the non-ground fault exists. In the following description, the resistance value of the ground insulation resistance 37 is R n0, and the resistance value of the ground insulation resistance 38 is R n1 .

地絡検出装置４は、正極側電源線３１に流れる電流と負極側電源線３２に流れる電流との不平衡電流を検出して電流検出値である電流Ｉｇとして出力する電流検出器である零相変流器４１と、正極側電源線３１と負極側電源線３２との間の電圧、すなわち太陽電池１の出力電圧を検出して第１の電圧検出値である電圧Ｖｐｎとして出力する第１の電圧検出部４２と、電圧検出用地絡抵抗４３と、正極側電源線３１と対地間または負極側電源線３２と対地間に電圧検出用地絡抵抗４３を接続する第１のスイッチ４４と、第１のスイッチ４４により正極側電源線３１と対地が接続されたとき、電圧検出用地絡抵抗４３の両端に発生する電圧を検出して第２の電圧検出値である電圧Ｖｐｇとして出力し、または第１のスイッチ４４により負極側電源線３２と対地が接続されたとき、電圧検出用地絡抵抗４３の両端に発生する電圧を検出して第２の電圧検出値である電圧Ｖｎｇとして出力する第２の電圧検出部４５と、零相変流器４１、第１の電圧検出部４２、および第２の電圧検出部４５の各々から出力された電圧Ｖｐｎ，Ｖｐｇ，Ｖｎｇと電流Ｉｇをデジタル値に変換して出力するＡＤ（Ａｎａｌｏｇ−ｔｏ−Ｄｉｇｉｔａｌ）変換部４６と、ＡＤ変換部４６で変換されたデジタル値の電圧Ｖｐｎ，Ｖｐｇ，Ｖｎｇと電流Ｉｇを入力として、パワーコンディショナ２が駅舎内電路系統５と解列状態にある場合における直流回路３の地絡とパワーコンディショナ２が駅舎内電路系統５と連系状態にある場合における直流回路３の地絡とを検出する地絡検出部４７と、地絡検出装置４に関連した各種情報を表示する表示装置４８とを有して構成される。 Ground detector 4, a current detector which outputs a current I g is a current detection value by detecting the unbalanced current between the current flowing through the current and the negative power source line 32 flowing to the cathode side power supply line 31 zero A voltage between the phase current transformer 41, the positive power supply line 31 and the negative power supply line 32, that is, the output voltage of the solar cell 1, is detected and output as a voltage V pn which is a first voltage detection value A voltage detection unit 42, a voltage detection ground resistor 43, and a first switch 44 connecting the voltage detection ground resistor 43 between the positive power supply line 31 and the ground or between the negative power supply line 32 and the ground; When the positive power supply line 31 and ground are connected by the first switch 44, a voltage generated at both ends of the voltage detection ground fault resistor 43 is detected and output as a voltage V pg which is a second voltage detection value, Or by the first switch 44 When the line 32 and ground is connected, the second voltage detecting unit 45 for outputting a voltage V ng a second voltage detection value by detecting the voltage generated across the voltage detecting land fault resistor 43, the zero Voltages V pn , V pg , and V ng output from each of phase current transformer 41, first voltage detection unit 42, and second voltage detection unit 45 and current I g are converted into digital values and output. The power conditioner 2 receives the voltage V pn , V pg , V ng of the digital value converted by the AD (Analog-to-Digital) conversion unit 46 and the AD conversion unit 46 and the current I g , and the power conditioner 2 A ground fault detection unit 47 for detecting a ground fault of the DC circuit 3 in the disconnection state and a ground fault of the DC circuit 3 in the case where the power conditioner 2 is in interconnection with the station electrical system 5 , Ground fault detection equipment 4 configured with a display device 48 for displaying various information related to.

第１のスイッチ４４は、地絡検出部４７からの制御により、正極側電源線３１または負極側電源線３２を、電圧検出用地絡抵抗４３を介して強制的に地絡させるためのスイッチである。   The first switch 44 is a switch for forcibly grounding the positive electrode side power supply line 31 or the negative electrode side power supply line 32 via the voltage detection ground fault resistor 43 under the control of the ground fault detection unit 47. .

実施の形態１では、電圧検出用地絡抵抗４３の抵抗値Ｒｇを、対地絶縁抵抗３５，３７の抵抗値より十分大きな値、例えば５０００ｋΩとしている。非地絡時、すなわちＲｐ１とＲｎ１の値が無限大とみなせるときの正極側の対地絶縁抵抗３３の抵抗値Ｒｐを２０００ｋΩとした場合、パワーコンディショナ２が解列状態、すなわち連系リレー２２が開放されているときに、第１のスイッチ４４を正極側電源線３１に接続した場合に発生する電圧Ｖｐｇと、第１のスイッチ４４を負極側電源線３２に接続した場合に発生する電圧Ｖｎｇは、それぞれ太陽電池１の発電電圧である電圧Ｖｐｎの半分の値となる。 In the first embodiment, the resistance value Rg of the voltage detection ground resistor 43 is set to a value sufficiently larger than the resistance value of the ground insulation resistors 35 and 37, for example, 5000 kΩ. Non ground fault, i.e. when the 2000kΩ the resistance R p of the positive electrode side of the ground insulation resistance 33 when the value of R p1 and R n1 is regarded as infinite, power conditioner 2 collapsed column state, i.e. interconnection The voltage V pg generated when the first switch 44 is connected to the positive power supply line 31 when the relay 22 is open, and the voltage V pg generated when the first switch 44 is connected to the negative power supply line 32 The voltage V ng to be generated is half the value of the voltage V pn which is the generated voltage of the solar cell 1.

零相変流器４１で検出される不平衡電流に関して説明する。直流回路３の負極側電源線３２に地絡が生じて地絡電流Ｉｇが流れたと仮定する。電流Ｉｇは、負極側電源線３２に流れる直流電流に重畳するため、太陽電池１から正極側電源線３１を介してパワーコンディショナ２に流れる直流電流と、パワーコンディショナ２から負極側電源線３２を介して太陽電池１に流れる直流電流との間には、電流Ｉｇ分の不平衡が生じる。図１では、太陽電池１から正極側電源線３１を介してパワーコンディショナ２に流れる直流電流を＋Ｉで表し、パワーコンディショナ２から負極側電源線３２を介して太陽電池１に流れる直流電流を−Ｉで表す。 The unbalanced current detected by the zero phase current transformer 41 will be described. It is assumed that a ground fault occurs in the negative side power supply line 32 of the DC circuit 3 and a ground current I g flows. Since the current I g is superimposed on the direct current flowing to the negative power supply line 32, the direct current flowing from the solar cell 1 to the power conditioner 2 via the positive power supply line 31 and the negative power supply line from the power conditioner 2 An imbalance of the current I g occurs between the direct current flowing to the solar cell 1 via 32. In FIG. 1, the direct current flowing from the solar cell 1 to the power conditioner 2 via the positive side power supply line 31 is represented by + I, and the direct current flowing from the power conditioner 2 to the solar cell 1 via the negative side power supply line 32 is Represented by -I.

地絡検出部４７は、地絡検出装置４を統括制御する機能と、電圧Ｖｐｎ，Ｖｐｇ，Ｖｎｇに基づいて対地絶縁抵抗３６の地絡抵抗値Ｒｐ１と対地絶縁抵抗３８の地絡抵抗値Ｒｎ１とを算出して直流回路３に発生した地絡を検出する第１の地絡検出部４７ａと、零相変流器４１から出力された電流Ｉｇに基づいて直流回路３に発生した地絡を検出する第２の地絡検出部４７ｂと、電圧Ｖｐｎ，Ｖｐｇ，Ｖｎｇに基づいてパワーコンディショナ２が駅舎内電路系統５と解列状態にあるか連系状態にあるかを判定する連系状態判定部４７ｃとを備える。地絡検出部４７はマイクロコンピュータで実現される。 The ground fault detection unit 47 has a function of generally controlling the ground fault detection device 4 and a ground fault resistance value R p1 of the ground insulation resistance 36 and a ground fault of the ground insulation resistance 38 based on the voltages V pn , V pg and V ng. The first ground fault detection unit 47a that calculates the resistance value R n1 and detects a ground fault generated in the DC circuit 3 and the DC circuit 3 based on the current I g output from the zero-phase current transformer 41 The power conditioner 2 is in a disconnection state or in an interconnection state with the in-station electrical circuit system 5 based on the second ground detection unit 47b that detects the generated ground and the voltages V pn , V pg and V ng And a connected state determination unit 47c that determines whether there is any. The ground fault detection unit 47 is realized by a microcomputer.

表示装置４８に表示される情報は、例えば地絡検出装置４が動作しているか停止しているかを示す動作状態情報、パワーコンディショナ２が駅舎内電路系統５と解列状態にあるか連系状態にあるかを示す連系状態情報である。   The information displayed on the display device 48 is, for example, operation state information indicating whether the ground fault detection device 4 is operating or stopped, and whether the power conditioner 2 is in a disconnection state with the station electrical circuit system 5 It is interconnection state information which shows whether it is in a state.

次に図２，３を参照しながら第１の地絡検出部４７ａにおける地絡検出方法について説明する。   Next, a ground fault detection method in the first ground fault detection unit 47a will be described with reference to FIGS.

図２は実施の形態１に係る地絡検出システムのパワーコンディショナが駅舎内電路系統と解列状態であるときに正極側電源線に地絡抵抗を接続した状態を示す図である。図３は実施の形態１に係る地絡検出システムのパワーコンディショナが駅舎内電路系統と解列状態であるときに負極側電源線に地絡抵抗を接続した状態を示す図である。   FIG. 2 is a diagram showing a state in which a ground fault resistance is connected to the positive electrode side power supply line when the power conditioner of the ground fault detection system according to the first embodiment is in a disconnection state with the station electrical circuit system. FIG. 3 is a diagram showing a state in which a ground fault resistance is connected to the negative power supply line when the power conditioner of the ground fault detection system according to Embodiment 1 is in a disconnection state with the station electrical circuit system.

電圧検出用地絡抵抗４３が正極側電源線３１に接続されている際の正極側電源線３１と対地間の電圧をＶｐｇとすると、電圧Ｖｐｇは下記（１）式より求められる。 Assuming that the voltage between the positive side power supply line 31 and the ground when the voltage detection ground resistor 43 is connected to the positive side power supply line 31 is V pg , the voltage V pg can be obtained from the following equation (1).

Figure 0006541485
Figure 0006541485

また、電圧検出用地絡抵抗４３が負極側電源線３２に接続されている際の負極側電源線３２と対地間の電圧をＶｎｇとすると、電圧Ｖｎｇは下記（２）式より求められる。 Further, when the voltage between the negative electrode side power supply line 32 and ground when the voltage detecting land fault resistor 43 is connected to the negative power supply line 32 and V ng, voltage V ng is calculated from the following equation (2).

Figure 0006541485
Figure 0006541485

（１）式，（２）式より、下記（３）式，（４）式が得られる。   Following (3) Formula and (4) Formula are obtained from (1) Formula and (2) Formula.

Figure 0006541485
Figure 0006541485

Figure 0006541485
Figure 0006541485

このように既知である電圧Ｖｐｇ，Ｖｎｇ，Ｖｐｎの値と、抵抗値Ｒｇの値に基づいて、対地絶縁抵抗３３，３４のそれぞれの抵抗値Ｒｐ，Ｒｎが算出できる。 The resistance values R p and R n of the ground insulation resistances 33 and 34 can be calculated based on the values of the voltages V pg , V ng and V pn thus known and the resistance value R g .

また抵抗値Ｒｐ，Ｒｎのそれぞれには、Ｒｐ＝Ｒｐ０／／Ｒｐ１、Ｒｎ＝Ｒｎ０／／Ｒｎ１の関係がある。初期状態にてＲｐ０とＲｎ０は等しいため、これらの抵抗値をＲｘ（≒Ｒｐ０≒Ｒｎ０）とすると、対地絶縁抵抗３６の地絡抵抗値Ｒｐ１と対地絶縁抵抗３８の地絡抵抗値Ｒｎ１はそれぞれ下記（５）式，（６）式で表される。 Further, the resistance values R p and R n have a relationship of R p = R p0 // R p1 and R n = R n0 // R n1 . Since R p0 and R n0 are equal in the initial state, assuming that their resistance value is R x (≒ R p0 RR n0 ), the ground fault resistance R p1 of the ground insulation resistance 36 and the ground fault of the ground insulation resistance 38 The resistance value R n1 is expressed by the following equations (5) and (6), respectively.

Figure 0006541485
Figure 0006541485

Figure 0006541485
Figure 0006541485

このように、電圧Ｖｐｇ，Ｖｎｇ，Ｖｐｎの値と、抵抗値Ｒｘ，Ｒｇの値に基づいて、正極側の対地絶縁抵抗３６における地絡抵抗値Ｒｐ１と負極側の対地絶縁抵抗３８における地絡抵抗値Ｒｎ１が算出できる。 Thus, based on the values of the voltages V pg , V ng and V pn and the values of the resistances R x and R g , the ground fault resistance R p1 at the positive side insulation resistance 36 and the negative side insulation to the ground The ground fault resistance value R n1 at the resistor 38 can be calculated.

ここで電圧検出用地絡抵抗４３の抵抗値Ｒｇについて説明する。上記（５）式，（６）式を用いて対地絶縁抵抗３６，３８の地絡抵抗値Ｒｐ１，Ｒｎ１を算出する場合、理論的には、電圧検出用地絡抵抗４３の抵抗値Ｒｇはどのような値でもよい。ただし、実際には、抵抗値Ｒｇが小さい場合、電圧検出用地絡抵抗４３が正極側電源線３１または負極側電源線３２に接続されると、抵抗値Ｒｇに一定値以上の電流Ｉｇが流れて、第２の地絡検出部４７ｂで地絡が検出される虞がある。そこで実施の形態１では、電圧検出用地絡抵抗４３の抵抗値Ｒｇを、対地絶縁抵抗３５，３７の抵抗値Ｒｐ０，Ｒｎ０より大きい値としている。 Here, the resistance value R g of the voltage detection ground resistor 43 will be described. When the ground fault resistance values R p1 and R n1 of the ground insulation resistances 36 and 38 are calculated using the above equations (5) and (6), theoretically, the resistance value R g of the voltage detection ground fault resistor 43 May be any value. However, in practice, when the resistance value R g is small, when the voltage detection ground fault resistance 43 is connected to the positive electrode side power supply line 31 or the negative electrode side power supply line 32, the current I g having a resistance value R g or more Flow may cause a ground fault to be detected by the second ground fault detection unit 47b. Therefore, in the first embodiment, the resistance value R g of the voltage detection ground resistor 43 is larger than the resistance values R p0 and R n0 of the ground insulation resistors 35 and 37.

具体的には、例えば、負極側電源線３２に地絡が発生し、負極側電源線３２と対地間の電圧が１００Ｖで、この１００Ｖに対して第２の地絡検出部４７ｂが１ｍＡ以上の地絡電流を検出することを想定した場合、第１の地絡検出部４７ａおよび第２の地絡検出部４７ｂが検出する地絡抵抗値を１００ｋΩとし、対地絶縁抵抗３６，３８の地絡抵抗値をＲｐ１＝１０００ｋΩ、Ｒｎ１＝５０ｋΩとし、対地絶縁抵抗３５，３７の初期値Ｒｘ（≒Ｒｐ０≒Ｒｎ０）を２０００ｋΩとすると、抵抗値Ｒｇとしては例えば５０００ｋΩ（２０００ｋΩ＜５０００ｋΩ）を選択する。 Specifically, for example, a ground fault occurs in the negative electrode side power supply line 32, the voltage between the negative electrode side power supply line 32 and the ground is 100 V, and the second ground fault detection unit 47b is 1 mA or more with respect to 100 V. Assuming that the ground fault current is detected, the ground fault resistance value detected by the first ground fault detection unit 47 a and the second ground fault detection unit 47 b is 100 kΩ, and the ground fault resistance of the ground insulation resistance 36, 38 is Assuming that the value is R p1 = 1000 kΩ and R n1 = 50 kΩ, and the initial value R x (≒ R p0 RR n0 ) of the ground insulating resistors 35 and 37 is 2000 kΩ, the resistance value R g is, for example, 5000 kΩ (2000 kΩ <5000 kΩ) Choose

このような場合において、電圧検出用地絡抵抗４３が正極側電源線３１に接続された状態では、正極側電源線３１と対地間の合成抵抗は５８８ｋΩ（Ｒｘ／／Ｒｐ１／／Ｒｇ）となり、負極側電源線３２と対地間の合成抵抗は４９ｋΩ（Ｒｘ／／Ｒｎ１）となる。そして、太陽電池１の発電電圧である電圧Ｖｐｎを２００Ｖとすると、電圧Ｖｐｇの大きさは１８５Ｖ、電圧Ｖｎｇの大きさは１５Ｖとなる。 In such a case, in a state where the voltage detection ground fault resistor 43 is connected to the positive electrode side power supply line 31, the combined resistance between the positive electrode side power supply line 31 and the ground is 588 kΩ (R x // R p1 // R g ) The combined resistance between the negative power supply line 32 and the ground is 49 kΩ (R x // R n1 ). When the voltage V pn which is the generated voltage of the solar cell 1 is 200 V, the magnitude of the voltage V pg is 185 V and the magnitude of the voltage V ng is 15 V.

一方、電圧検出用地絡抵抗４３が負極側電源線３２に接続された状態では、正極側電源線３１と対地間の合成抵抗は６６７ｋΩ（Ｒｘ／／Ｒｐ１）となり、負極側電源線３２と対地間の合成抵抗は４８ｋΩ（Ｒｘ／／Ｒｎ１／／Ｒｇ）となる。そして、この際の電圧Ｖｐｇの大きさは１８６Ｖ、電圧Ｖｎｇの大きさは１４Ｖとなる。 On the other hand, in a state where the voltage detection ground resistor 43 is connected to the negative power supply line 32, the combined resistance between the positive power supply line 31 and the ground is 667 kΩ (R x // R p1 ). The combined resistance between the ground and the ground is 48 kΩ (R x // R n1 // R g ). The magnitude of the voltage V pg at this time is 186 V, and the magnitude of the voltage V ng is 14 V.

これらの値により、前述した（５）式，（６）式を用いて対地絶縁抵抗３６，３８の地絡抵抗値Ｒｐ１，Ｒｎ１を求めると、Ｒｐ１＝１０００ｋΩ、Ｒｎ１＝５０ｋΩとなり、検出する地絡抵抗の設定値を１００ｋΩとした場合、Ｒｎ１の値が設定値未満となるため、第１の地絡検出部４７ａは負極側電源線３２に地絡が発生していると判定する。 From these values, the ground fault resistance values R p1 and R n1 of the ground insulation resistances 36 and 38 are obtained using the above-mentioned equations (5) and (6), R p1 = 1000 kΩ and R n1 = 50 kΩ. When the set value of the ground fault resistance to be detected is 100 kΩ, the value of R n1 is less than the set value, so the first ground fault detection unit 47 a determines that a ground fault occurs in the negative electrode side power supply line 32 Do.

このように第１の地絡検出部４７ａは、正極側電源線３１と対地間に地絡抵抗を接続することで発生する電圧、または負極側電源線３２と対地間に地絡抵抗を接続することで発生する電圧に基づいて、絶縁抵抗値を算出して地絡の発生を検出する。ところが、前述したように駅舎内電路系統５と連系状態にあるトランスレス方式のパワーコンディショナ２では、正極側電源線３１と対地間の電位が変動し、また負極側電源線３２と対地間の電位が変動する。そのため、第１の地絡検出部４７ａは、パワーコンディショナ２が駅舎内電路系統５と解列状態にある場合には正確な地絡検出が可能であるが、パワーコンディショナ２が駅舎内電路系統５と連系状態にある場合には正確な地絡検出が出来ない虞がある。   As described above, the first ground fault detection unit 47a connects the ground fault resistance between the positive power supply line 31 and the ground, or generates the voltage generated by connecting the ground resistance between the negative power supply line 32 and the ground. The insulation resistance value is calculated based on the voltage generated thereby to detect the occurrence of the ground fault. However, as described above, in the transformerless type power conditioner 2 connected to the station electrical circuit system 5, the potential between the positive side power supply line 31 and the ground fluctuates, and the negative side power supply line 32 to the ground The potential of the Therefore, although the first ground fault detection unit 47a can accurately detect a ground fault when the power conditioner 2 is in a disconnection state with the station electrical circuit system 5, the power conditioner 2 can be used in the station electrical circuit. If the system 5 and the system 5 are connected, there is a possibility that accurate ground fault detection can not be performed.

次に図４，５を参照しながら第２の地絡検出部４７ｂにおける地絡検出方法について説明する。   Next, a ground fault detection method in the second ground fault detection unit 47b will be described with reference to FIGS.

図４は実施の形態１に係る地絡検出システムのパワーコンディショナが駅舎内電路系統と連系状態である場合に正極側電源線に地絡が発生したときに流れる地絡電流の経路を表す図である。図５は実施の形態１に係る地絡検出システム地絡検出システムのパワーコンディショナが駅舎内電路系統と連系状態である場合に負極側電源線に地絡が発生したときに流れる地絡電流の経路を表す図である。   FIG. 4 shows a path of a ground fault current which flows when a ground fault occurs in the positive electrode side power supply line when the power conditioner of the ground fault detection system according to the first embodiment is in an interconnection state with the station electrical circuit system. FIG. FIG. 5 is a ground fault current that flows when a ground fault occurs on the negative side power supply line when the power conditioner of the ground fault detection system according to the first embodiment is in an interconnection state with the station electrical circuit system. Is a diagram showing a path of

正極側電源線３１が地絡した場合、直流回路３では、（Ａ）対地絶縁抵抗３６、（Ｂ）パワーコンディショナ２の交流側のＶ相接地線、（Ｃ）負極側電源線３２、の順で地絡電流の流れる経路が形成される。その際の正極側電源線３１と対地間の電圧をＶｐｅとすると、零相変流器４１は電流Ｉｇ＝Ｖｐｅ／Ｒｐ１を検出する。 When the positive side power supply line 31 is grounded, in the DC circuit 3, (A) ground insulation resistance 36, (B) AC phase V phase ground line of the power conditioner 2, (C) negative side power supply line 32, In this order, a path through which the ground fault current flows is formed. Assuming that the voltage between the positive electrode side power supply line 31 and the ground at that time is V pe , the zero phase current transformer 41 detects a current I g = V pe / R p1 .

負極側電源線３２が地絡した場合、直流回路３では、（Ａ）正極側電源線３１、（Ｂ）パワーコンディショナ２の交流側のＶ相接地線、（Ｃ）対地絶縁抵抗３８、の順で地絡電流の流れる経路が形成される。その際の負極側電源線３２と対地間の電圧をＶｎｅとすると、零相変流器４１は電流Ｉｇ＝Ｖｎｅ／Ｒｎ１を検出する。第２の地絡検出部４７ｂは、電流Ｉｇにより正極側電源線３１と負極側電源線３２の各々で発生した地絡を検出する。 When the negative electrode side power supply line 32 is grounded, in the DC circuit 3, (A) positive electrode side power supply line 31, (B) AC phase V phase ground line of the power conditioner 2, (C) ground insulation resistance 38, In this order, a path through which the ground fault current flows is formed. Assuming that the voltage between the negative electrode side power supply line 32 and the ground at that time is V ne , the zero phase current transformer 41 detects the current I g = V ne / R n1 . Second earth fault detection unit 47b detects a ground fault occurring in each of the positive electrode side power supply line 31 and the negative power supply line 32 by the current I g.

第２の地絡検出部４７ｂは、電流Ｉｇの値により地絡判定を行うため、パワーコンディショナ２の連系時における正極側電源線３１と対地間の電位変動は受けず、また負極側電源線３２と対地間の電位変動影響は受けない。ところが、パワーコンディショナ２の解列時には連系リレー２２が開放され、直流回路３が交流側の接地から切り離される。そのため解列時の零相変流器４１では電流Ｉｇを検出することができず、第２の地絡検出部４７ｂでは地絡を検出することができない。 Second earth fault detection unit 47b, in order to perform the ground fault determination on the value of the current I g, the potential variation between the positive electrode side power supply line 31 and ground at the time of power conditioner 2 of the communication system is not received, also the anode side There is no influence of potential fluctuation between the power supply line 32 and the ground. However, when the power conditioner 2 is disconnected, the interconnection relay 22 is opened, and the DC circuit 3 is disconnected from the ground on the AC side. Therefore, the zero phase current transformer 41 at the time of disconnection can not detect the current I g , and the second ground fault detection unit 47 b can not detect a ground fault.

そこで実施の形態１の連系状態判定部４７ｃは、電圧Ｖｐｎおよび電圧Ｖｎｇに基づいてパワーコンディショナ２が連系状態であるか解列状態であるかを判定し、判定結果に応じて第１の地絡検出部４７ａによる地絡判定と第２の地絡検出部４７ｂによる地絡判定とを実行する。 Therefore, interconnection state determination unit 47c according to the first embodiment determines whether power conditioner 2 is in the interconnection state or the disconnection state based on voltage V pn and voltage V ng , and according to the determination result. The ground fault determination by the first ground fault detection unit 47a and the ground fault determination by the second ground fault detection unit 47b are executed.

パワーコンディショナ２は一般的に電圧Ｖｐｎの値が稼働電圧値未満であるときに駅舎内電路系統と連系しており、解列状態では正極側電源線３１と対地間の電位と、負極側電源線３２と対地間の電位は、各々安定した電位となる。そのため、電圧Ｖｐｎの値が稼働電圧値以上であり、かつ、電圧Ｖｎｇの値が一定範囲内であるときに解列状態であると判定し、電圧Ｖｐｎが稼働電圧値以下または電圧Ｖｎｇが一定範囲内ではない場合には連系状態であると判定することができる。稼働電圧値とは、パワーコンディショナ２が交流電力の出力動作を行うときに検出される電圧Ｖｐｎの値である。具体的には、早朝、夕方、夜間といった太陽電池１の発電量が比較的少ない時間帯においては、パワーコンディショナ２に印加される電圧Ｖｐｎは稼働電圧値未満の値を示すが、日中の時間帯においては、パワーコンディショナ２に印加される電圧Ｖｐｎは稼働電圧値以上の値を示す。また、一定範囲とは、パワーコンディショナ２が駅舎内電路系統５と解列状態にあるときに検出される電圧の範囲であり、例えば電圧Ｖｐｎの半分の値を基準とした電圧の範囲で定義される。電圧Ｖｎｇと比較する値を一定範囲とすることにより、太陽電池１の発電量の変化による電圧Ｖｎｇの変動にも対応できる。稼働電圧値と一定範囲は連系状態判定部４７ｃに設定されている。 Power conditioner 2 generally interconnects with the station electrical circuit when the value of voltage V pn is less than the operating voltage value, and in the disconnection state, the potential between positive electrode side power supply line 31 and ground, and the negative electrode The potential between the side power supply line 32 and the ground is a stable potential. Therefore, when the value of voltage V pn is equal to or higher than the operating voltage value and the value of voltage V ng is within the predetermined range, it is determined that the disconnection state is established, and voltage V pn is lower than the operating voltage value or voltage V If ng is not within the predetermined range, it can be determined that the connection is established. The operating voltage value is a value of the voltage V pn detected when the power conditioner 2 performs an output operation of AC power. Specifically, in a time zone where the amount of power generation of the solar cell 1 is relatively small, such as early morning, evening, and night, the voltage V pn applied to the power conditioner 2 shows a value lower than the operating voltage value. In the time zone, the voltage V pn applied to the power conditioner 2 shows a value equal to or higher than the operating voltage value. Further, the predetermined range is a range of voltage detected when the power conditioner 2 is in a disconnection state with the station electrical circuit system 5, for example, a voltage range based on a half value of the voltage V pn It is defined. By setting the value to be compared with the voltage V ng within a certain range, it is possible to cope with the fluctuation of the voltage V ng due to the change of the power generation amount of the solar cell 1. The operating voltage value and the fixed range are set in the interconnection state determination unit 47c.

連系状態判定部４７ｃは、電圧Ｖｐｎの値が稼働電圧値以上であり、かつ、電圧Ｖｎｇの値が一定範囲内である場合、パワーコンディショナ２が解列状態であると判定し、電圧Ｖｐｎの値が稼働電圧値未満であり、または、電圧Ｖｐｎの値が稼働電圧値以上であっても電圧Ｖｎｇの値が一定範囲内ではない場合、パワーコンディショナ２が連系状態であると判定する。そして、解列状態であると判定された場合、第１の地絡検出部４７ａで地絡検出処理が実行され、連系状態であると判定された場合、第２の地絡検出部４７ｂで地絡検出処理が実行される。 When the value of voltage V pn is equal to or higher than the operating voltage value and the value of voltage V ng is within a predetermined range, interconnection state determination unit 47 c determines that power conditioner 2 is in the disconnection state, If the value of voltage V pn is less than the operating voltage value, or if the value of voltage V ng is not within the predetermined range even if the value of voltage V pn is more than the operating voltage value, the power conditioner 2 is in the interconnection state It is determined that When it is determined that the connection state is the disconnection state, the ground detection process is executed by the first ground detection unit 47a, and when it is determined that the connection state is the connection state, the second ground detection unit 47b is performed. A ground fault detection process is performed.

図６は実施の形態１に係る駅舎補助電源用地絡検出装置の地絡検出部が実行する処理のフローチャートである。連系状態判定部４７ｃは検出された電圧Ｖｐｎおよび電圧Ｖｎｇの値を記録し（ステップＳ１）、電圧Ｖｐｎの値が稼働電圧値以上であり（ステップＳ２，Ｙｅｓ）、電圧Ｖｎｇの値が一定範囲内である場合（ステップＳ３，Ｙｅｓ）、パワーコンディショナ２が解列状態であると判定する（ステップＳ４）。 FIG. 6 is a flowchart of processing executed by the ground fault detection unit of the station building auxiliary power ground fault detection device according to the first embodiment. Interconnection state determining unit 47c records the detected values of the voltage V pn and the voltage V ng (step S1), and it is the value of the voltage V pn operating voltage value or more (step S2, Yes), the voltage V ng If the value is within the predetermined range (Yes at step S3), it is determined that the power conditioner 2 is in the disconnection state (step S4).

パワーコンディショナ２が解列状態と判定された場合、地絡検出部４７により第１のスイッチ４４が制御され、正極側電源線３１に電圧検出用地絡抵抗４３が接続され（ステップＳ５）、第１の地絡検出部４７ａはこのときに検出された電圧Ｖｐｇを記録する（ステップＳ６）。その後、地絡検出部４７により第１のスイッチ４４が制御され、正極側電源線３１から電圧検出用地絡抵抗４３が切り離され（ステップＳ７）、負極側電源線３２に電圧検出用地絡抵抗４３が接続され（ステップＳ８）、第１の地絡検出部４７ａはこのとき検出された電圧Ｖｎｇを記録する（ステップＳ９）。そして地絡検出部４７により第１のスイッチ４４が制御され、負極側電源線３２から電圧検出用地絡抵抗４３が切り離される（ステップＳ１０）。第１の地絡検出部４７ａは、電圧Ｖｐｎ，Ｖｐｇ，Ｖｎｇに基づいて地絡抵抗値Ｒｐ１，Ｒｎ１を算出し（ステップＳ１１）、その算出結果から地絡を検出する（ステップＳ１２）。 When the power conditioner 2 is determined to be in the disconnection state, the first switch 44 is controlled by the ground fault detection unit 47, and the voltage detection ground fault resistor 43 is connected to the positive power supply line 31 (step S5). The ground fault detection unit 47a of 1 records the voltage V pg detected at this time (step S6). Thereafter, the first switch 44 is controlled by the ground fault detection unit 47, the voltage detection ground fault resistor 43 is disconnected from the positive electrode side power supply line 31 (step S7), and the voltage detection ground fault resistor 43 is connected to the negative electrode side power supply line 32. Connected (step S8), the first ground fault detection unit 47a records the voltage V ng detected at this time (step S9). Then, the first switch 44 is controlled by the ground fault detection unit 47, and the voltage detection ground fault resistor 43 is disconnected from the negative electrode side power supply line 32 (step S10). The first ground fault detection unit 47a calculates ground fault resistance values R p1 and R n1 based on the voltages V pn , V pg and V ng (step S11), and detects the ground fault from the calculation result (step S11) S12).

電圧Ｖｐｎの値が稼働電圧値以上ではなく（ステップＳ２，Ｎｏ）、または電圧Ｖｐｎの値が稼働電圧値以上ではあるが電圧Ｖｎｇの値が一定範囲内ではない場合（ステップＳ３，Ｎｏ）、連系状態判定部４７ｃは、パワーコンディショナ２が連系状態であると判定する（ステップＳ１３）。パワーコンディショナ２が連系状態と判定された場合、第２の地絡検出部４７ｂは電流Ｉｇの値を記録し（ステップＳ１４）、電流Ｉｇの値に基づいて地絡を検出する（ステップＳ１５）。 When the value of voltage V pn is not higher than the operating voltage value (Step S2, No), or the value of voltage V pn is higher than the operating voltage value but the value of voltage V ng is not within the predetermined range (Step S3, No And the interconnection state determination unit 47c determines that the power conditioner 2 is in the interconnection state (step S13). If the power conditioner 2 is determined to interconnection state, the second earth fault detection unit 47b records the value of the current I g (step S14), and detects a ground fault based on the value of the current I g ( Step S15).

実施の形態２．
図７は実施の形態２に係る地絡検出システムを示したものである。実施の形態２の地絡検出装置４Ａは、実施の形態１の地絡検出装置４の構成に加えて、第１のスイッチ４４を介して、正極側電源線３１と対地間または負極側電源線３２と対地間に接続される電流検出用地絡抵抗４９と、第１のスイッチ４４に電圧検出用地絡抵抗４３が接続されているときには、第２のスイッチ５０に電流検出用地絡抵抗４９を接続せず、第２のスイッチ５０に電流検出用地絡抵抗４９が接続されているときには、第１のスイッチ４４に電圧検出用地絡抵抗４３を接続しない第２のスイッチ５０とを備える。第２のスイッチ５０は、地絡検出部４７Ａにより制御される。 Second Embodiment
FIG. 7 shows a ground fault detection system according to a second embodiment. In addition to the configuration of the ground fault detection device 4 of the first embodiment, the ground fault detection device 4A of the second embodiment is configured to connect the positive electrode side power supply line 31 to the ground or the negative electrode side power supply line via the first switch 44. When the current detection ground resistor 49 connected between the ground and the ground 32 and the voltage detection ground resistor 43 are connected to the first switch 44, the current detection ground resistor 49 is connected to the second switch 50. Instead, when the current detection ground fault resistor 49 is connected to the second switch 50, the second switch 50 does not connect the voltage detection ground fault resistor 43 to the first switch 44. The second switch 50 is controlled by the ground fault detection unit 47A.

さらに実施の形態２の地絡検出部４７Ａは、正極側電源線３１と対地間または負極側電源線３２と対地間に電流検出用地絡抵抗４９を接続することにより検出される不平衡電流の電流検出値と、電圧Ｖｐｎとに基づいて、直流回路３に発生した地絡を検出する第３の地絡検出部４７ｄを備える。 Furthermore, the ground fault detection unit 47A according to the second embodiment is a current of an unbalanced current detected by connecting a ground fault resistance 49 for current detection between the positive side power supply line 31 and the ground or between the negative side power supply line 32 and the ground. A third ground fault detection unit 47d that detects a ground fault generated in the DC circuit 3 based on the detected value and the voltage V pn is provided.

図７に示す太陽電池１が複数存在する場合、複数の太陽電池１の各々には直流回路３が接続され、複数の太陽電池１の各々に対応した直流回路３の正極側電源線３１と負極側電源線３２は、１組の正極側電源線３１と負極側電源線３２にまとめられてパワーコンディショナ２に接続される。このように構成された地絡検出システム１００Ａでは、図７に示す零相変流器４１が複数の直流回路３の各々に設置され、パワーコンディショナ２に接続される１組の正極側電源線３１と負極側電源線３２に対して第１の電圧検出部４２と第２の電圧検出部４５が設置される。この場合、パワーコンディショナ２には、複数の直流回路３の各々の電圧が一括で印加されるため、第１の電圧検出部４２と第２の電圧検出部４５では、複数の太陽電池１の各々に対応した直流回路３に印加される電圧を個別に検出することはできない。従って、パワーコンディショナ２が駅舎内電路系統５と解列状態にある場合、第１の地絡検出部４７ａでは、複数の太陽電池１の各々に対応した直流回路３の内、何れかの直流回路３で発生した地絡を検出することはできるが、地絡が発生している直流回路３を判別することはできない。   When there are a plurality of solar cells 1 shown in FIG. 7, DC circuit 3 is connected to each of the plurality of solar cells 1, and positive electrode side power supply line 31 and negative electrode of DC circuit 3 corresponding to each of the plurality of solar cells 1 The side power supply lines 32 are combined into one set of the positive side power supply line 31 and the negative side power supply line 32 and connected to the power conditioner 2. In the ground fault detection system 100A configured as described above, one set of positive side power supply lines connected to the power conditioner 2 with the zero phase current transformer 41 shown in FIG. 7 installed in each of the plurality of DC circuits 3 A first voltage detection unit 42 and a second voltage detection unit 45 are provided for the power supply line 31 and the negative electrode side power supply line 32. In this case, since the voltages of the plurality of direct current circuits 3 are applied to the power conditioner 2 at one time, the first voltage detection unit 42 and the second voltage detection unit 45 The voltage applied to the DC circuit 3 corresponding to each can not be individually detected. Therefore, when the power conditioner 2 is in the disconnection state with the station electrical circuit system 5, in the first ground fault detection unit 47 a, any one of the direct current circuits 3 corresponding to each of the plurality of solar cells 1. Although the ground fault generated in the circuit 3 can be detected, the DC circuit 3 in which the ground fault is generated can not be determined.

実施の形態２に係る地絡検出システム１００Ａの地絡検出装置４Ａは、複数の太陽電池１が接続されたパワーコンディショナ２が駅舎内電路系統５と解列状態にある場合でも、電流検出用地絡抵抗４９を対地間に強制的に地絡させることで発生する地絡電流を、直流回路３の各々に設置された複数の零相変流器４１で検出し、複数の零相変流器４１の各々で検出された電流Ｉｇと、電圧Ｖｐｎとに基づいて、地絡が発生している直流回路３を判別する。 The ground fault detection device 4A of the ground fault detection system 100A according to the second embodiment has the current detection ground even when the power conditioner 2 to which the plurality of solar cells 1 are connected is in a disjunction state with the station electrical circuit system 5. A plurality of zero phase current transformers are detected by detecting a ground fault current generated by forcing a ground resistance 49 to ground between grounds by a plurality of zero phase current transformers 41 installed in each of the DC circuits 3 Based on the current I g detected by each of 41 and the voltage V pn , the DC circuit 3 in which the ground fault is generated is determined.

次に図８，９を参照しながら第３の地絡検出部４７ｄにおける地絡検出方法について説明する。   Next, a ground fault detection method in the third ground fault detection unit 47d will be described with reference to FIGS.

図８は実施の形態２に係る地絡検出システムのパワーコンディショナが駅舎内電路系統と解列状態である場合に負極側電源線に電流検出用地絡抵抗を接続したときに流れる地絡電流の経路を表す状態を表す図である。図９は実施の形態２に係る地絡検出システムのパワーコンディショナが駅舎内電路系統と解列状態である場合に正極側電源線に電流検出用地絡抵抗を接続したときに流れる地絡電流の経路を表す状態を表す図である。   FIG. 8 is a ground fault current that flows when the ground fault resistance for current detection is connected to the negative power supply line when the power conditioner of the ground fault detection system according to the second embodiment is in a disconnection state with the station electrical circuit system. It is a figure showing the state showing a path. FIG. 9 is a ground fault current that flows when the ground fault resistance for current detection is connected to the positive-side power line when the power conditioner of the ground fault detection system according to the second embodiment is in a disconnection state with the station electrical circuit system. It is a figure showing the state showing a path.

図８に示すように正極側電源線３１が地絡した場合、直流回路３では、（Ａ）対地絶縁抵抗３６、（Ｂ）電流検出用地絡抵抗４９に接続された接地線、（Ｃ）負極側電源線３２の順で地絡電流の流れる経路が形成される。その際、零相変流器４１は地絡電流の検出値である電流Ｉｐｇを検出する。電流Ｉｐｇは下記（７）式より求められる。 As shown in FIG. 8, when the positive electrode side power supply line 31 is grounded, in the DC circuit 3, (A) ground insulation resistance 36, (B) ground line connected to current detection ground fault resistance 49, (C) negative electrode A path through which a ground fault current flows is formed in the order of the side power supply lines 32. At that time, the zero phase current transformer 41 detects a current I pg which is a detected value of the ground fault current. The current I pg can be obtained by the following equation (7).

Figure 0006541485
Figure 0006541485

（７）式から、対地絶縁抵抗３６の地絡抵抗値Ｒｐ１は下記（８）式で表される。 From the equation (7), the ground fault resistance value R p1 of the ground insulation resistance 36 is expressed by the following equation (8).

Figure 0006541485
Figure 0006541485

図９に示すように負極側電源線３２が地絡した場合、直流回路３では、（Ａ）正極側電源線３１、（Ｂ）電流検出用地絡抵抗４９に接続された接地線、（Ｃ）対地絶縁抵抗３８の順で地絡電流の流れる経路が形成される。その際、零相変流器４１は地絡電流の検出値である電流Ｉｎｇを検出する。電流Ｉｎｇは下記（９）式より求められる。 When the negative electrode side power supply line 32 is grounded as shown in FIG. 9, in the DC circuit 3, (A) positive electrode side power supply line 31, (B) ground line connected to current detection ground resistance 49, (C) A path through which a ground current flows is formed in the order of the ground insulation resistance 38. At that time, the zero-phase current transformer 41 detects a current I ng a detected value of the ground fault current. The current Ing is determined by the following equation (9).

Figure 0006541485
Figure 0006541485

（９）式から、対地絶縁抵抗３８の地絡抵抗値Ｒｎ１は下記（１０）式で表される。 From the equation (9), the ground fault resistance value R n1 of the ground insulation resistance 38 is expressed by the following equation (10).

Figure 0006541485
Figure 0006541485

ここで、電流検出用地絡抵抗４９には、対地間に接続した場合に零相変流器４１により不平衡電流を検出できる電流値の電流を流さなければならない。そのため、電流検出用地絡抵抗４９の抵抗値Ｒｇ１は、負極側電源線３２で地絡が発生した際、負極側電源線３２と対地間の電圧が１００Ｖに対して第２の地絡検出部４７ｂが１ｍＡ以上の地絡電流を検出することを想定したとき、１００ｋΩに近い抵抗値、例えば１５０ｋΩを選択する。 Here, in the current detection ground fault resistance 49, a current having a current value that allows detection of an unbalanced current by the zero-phase current transformer 41 when connected between grounds must flow. Therefore, the resistance value R g1 of the current detection ground fault resistor 49 is a second ground fault detection portion when the voltage between the negative power line 32 and the ground is 100 V when a ground fault occurs in the negative power line 32. Assuming that 47b detects a ground current of 1 mA or more, a resistance value close to 100 kΩ, for example, 150 kΩ is selected.

図１０は実施の形態２に係る駅舎補助電源用地絡検出装置の地絡検出部が実行する処理のフローチャートである。連系状態判定部４７ｃは、検出された電圧Ｖｐｎおよび電圧Ｖｎｇの値を記録し（ステップＳ２１）、電圧Ｖｐｎの値が稼働電圧値以上であり（ステップＳ２２，Ｙｅｓ）、電圧Ｖｎｇの値が一定範囲内である場合（ステップＳ２３，Ｙｅｓ）、パワーコンディショナ２が解列状態であると判定する（ステップＳ２４）。 FIG. 10 is a flowchart of processing executed by the ground fault detection unit of the station building auxiliary power ground fault detection device according to the second embodiment. Interconnection state determining unit 47c records the detected voltage value of the V pn and the voltage V ng (step S21), and it is the value of the voltage V pn operating voltage value or more (step S22, Yes), the voltage V ng If the value of is within the predetermined range (step S23, Yes), it is determined that the power conditioner 2 is in the disconnection state (step S24).

パワーコンディショナ２が解列状態と判定された場合、地絡検出部４７Ａにより第２のスイッチ５０が投入される（ステップＳ２５）。第２のスイッチ５０が投入されることにより第１のスイッチ４４に電圧検出用地絡抵抗４３が接続され、第１のスイッチ４４と電流検出用地絡抵抗４９の接続状態が解除される。なお、ここでは第１のスイッチ４４は正極側電源線３１に接続されているものとする。これにより正極側電源線３１に電圧検出用地絡抵抗４３が接続され（ステップＳ２６）、第１の地絡検出部４７ａはこのとき検出された電圧Ｖｐｇを記録する（ステップＳ２７）。その後、地絡検出部４７Ａにより第１のスイッチ４４が制御され、正極側電源線３１から電圧検出用地絡抵抗４３が切り離され（ステップＳ２８）、負極側電源線３２に電圧検出用地絡抵抗４３が接続され（ステップＳ２９）、第１の地絡検出部４７ａはこのとき検出された電圧Ｖｎｇを記録する（ステップＳ３０）。地絡検出部４７Ａにより第１のスイッチ４４が制御され、負極側電源線３２から電圧検出用地絡抵抗４３が切り離される（ステップＳ３１）。第１の地絡検出部４７ａは、電圧Ｖｐｎ，Ｖｐｇ，Ｖｎｇに基づいて地絡抵抗値Ｒｐ１，Ｒｎ１を算出し（ステップＳ３２）、その算出結果から地絡を検出する。地絡抵抗値Ｒｐ１が一定値以下、または地絡抵抗値Ｒｎ１が一定値以下である場合（ステップＳ３３，Ｙｅｓ）、第１の地絡検出部４７ａは地絡を検出し（ステップＳ３４）、ステップＳ３５以降の処理が行われる。地絡抵抗値Ｒｐ１が一定値以下ではなく、または地絡抵抗値Ｒｎ１が一定値以下ではない場合（ステップＳ３３，Ｎｏ）、第１の地絡検出部４７ａは地絡を検出することなく処理を終了する。 When it is determined that the power conditioner 2 is in the disconnection state, the second switch 50 is turned on by the ground fault detection unit 47A (step S25). When the second switch 50 is turned on, the voltage detection ground fault resistor 43 is connected to the first switch 44, and the connection state of the first switch 44 and the current detection ground fault resistor 49 is released. Here, it is assumed that the first switch 44 is connected to the positive electrode side power supply line 31. As a result, the ground terminal for voltage detection 43 is connected to the positive side power supply line 31 (step S26), and the first ground detection unit 47a records the voltage V pg detected at this time (step S27). Thereafter, the first switch 44 is controlled by the ground fault detection unit 47A, the voltage detection ground fault resistor 43 is disconnected from the positive electrode side power supply line 31 (step S28), and the voltage detection ground fault resistor 43 is connected to the negative electrode side power supply line 32. Connected (step S29), the first ground fault detection unit 47a records the voltage V ng detected at this time (step S30). The first switch 44 is controlled by the ground fault detection unit 47A, and the voltage detection ground fault resistor 43 is disconnected from the negative electrode side power supply line 32 (step S31). The first ground fault detection unit 47a calculates ground fault resistance values R p1 and R n1 based on the voltages V pn , V pg and V ng (step S32), and detects the ground fault from the calculation result. When the ground fault resistance value R p1 is equal to or less than a predetermined value or the ground fault resistance value R n1 is equal to or less than a predetermined value (Yes in step S33), the first ground fault detection unit 47a detects a ground fault (step S34) , And the processes after step S35 are performed. When ground fault resistance value R p1 is not equal to or less than a fixed value or ground fault resistance value R n1 is not equal to or less than a fixed value (No in step S33), first ground fault detection unit 47a does not detect a ground fault. End the process.

第１の地絡検出部４７ａが地絡を検出した後、地絡検出部４７Ａにより第２のスイッチ５０が開放される（ステップＳ３５）。第２のスイッチ５０が開放されることにより第１のスイッチ４４と電圧検出用地絡抵抗４３の接続状態が解除され、第１のスイッチ４４に電流検出用地絡抵抗４９が接続される。なお、ここでは第１のスイッチ４４は正極側電源線３１に接続されているものとする。   After the first ground fault detection unit 47a detects a ground fault, the second switch 50 is opened by the ground fault detection unit 47A (step S35). When the second switch 50 is opened, the connection state of the first switch 44 and the voltage detection ground fault resistor 43 is released, and the current detection ground fault resistor 49 is connected to the first switch 44. Here, it is assumed that the first switch 44 is connected to the positive electrode side power supply line 31.

これにより正極側電源線３１に電流検出用地絡抵抗４９が接続され（ステップＳ３６）、第３の地絡検出部４７ｄはこのとき検出された電流Ｉｐｇを記録する（ステップＳ３７）。地絡検出部４７Ａにより第１のスイッチ４４が制御され、正極側電源線３１から電流検出用地絡抵抗４９が切り離され（ステップＳ３８）、負極側電源線３２に電流検出用地絡抵抗４９が接続される（ステップＳ３９）。第３の地絡検出部４７ｄはこのとき検出された電流Ｉｎｇを記録する（ステップＳ４０）。そして地絡検出部４７Ａにより第１のスイッチ４４が制御され、負極側電源線３２から電流検出用地絡抵抗４９が切り離される（ステップＳ４１）。 As a result, the ground fault resistor 49 for current detection is connected to the positive electrode side power supply line 31 (step S36), and the third ground fault detection unit 47d records the current I pg detected at this time (step S37). The first switch 44 is controlled by the ground fault detection unit 47A, and the current detection ground fault resistance 49 is disconnected from the positive side power supply line 31 (step S38), and the current detection ground fault resistance 49 is connected to the negative side power supply line 32. (Step S39). The third earth fault detection unit 47d records the current I ng detected this time (step S40). Then, the first switch 44 is controlled by the ground fault detection unit 47A, and the current detection ground fault resistance 49 is disconnected from the negative electrode side power supply line 32 (step S41).

第３の地絡検出部４７ｄは、電圧Ｖｐｎ，電流Ｉｐｇ，Ｉｎｇに基づいて地絡抵抗値Ｒｐ１，Ｒｎ１を算出し（ステップＳ４２）、その算出結果から複数の直流回路３に各々における地絡を検出する（ステップＳ４３）。 The third ground fault detection unit 47d calculates ground fault resistance values R p1 and R n1 based on the voltage V pn and the currents I pg and I ng (step S42), and based on the calculation results, the plurality of DC circuits 3 A ground fault in each is detected (step S43).

電圧Ｖｐｎの値が稼働電圧値以上ではなく（ステップＳ２２，Ｎｏ）、または電圧Ｖｐｎの値が稼働電圧値以上ではあるが電圧Ｖｎｇの値が一定範囲内ではない場合（ステップＳ２３，Ｎｏ）、連系状態判定部４７ｃは、パワーコンディショナ２が連系状態であると判定する（ステップＳ４４）。パワーコンディショナ２が連系状態と判定された場合、第２の地絡検出部４７ｂは、電流Ｉｇの値を記録し（ステップＳ４５）、電流Ｉｇの値に基づいて地絡を検出する（ステップＳ４６）。 When the value of voltage V pn is not higher than the operating voltage value (step S22, No) or the value of voltage V pn is higher than the operating voltage value but the value of voltage V ng is not within the predetermined range (step S23, No And the interconnection state determination unit 47c determines that the power conditioner 2 is in the interconnection state (step S44). If the power conditioner 2 is determined to interconnection state, the second earth fault detection unit 47b records the value of the current I g (step S45), and detects a ground fault based on the value of the current I g (Step S46).

なお実施の形態１，２の連系状態判定部４７ｃは、電圧Ｖｐｎ，Ｖｎｇの値でパワーコンディショナ２が連系状態であるか解列状態であるかを判定する構成であるが、電圧Ｖｐｎ，Ｖｎｇの代わりに電圧Ｖｐｎ，Ｖｐｇの値でパワーコンディショナ２が連系状態であるか解列状態であるかを判定する構成でもよい。また実施の形態１，２では、地絡検出装置４，４Ａに設けられた表示装置４８に各種情報を表示する構成例を説明したが、地絡検出装置４，４Ａの外部に設けられた外部表示装置に地絡検出装置４，４Ａに関連した各種情報を表示する構成でもよい。 Although the interconnection state determination unit 47c in the first and second embodiments is configured to determine whether the power conditioner 2 is in the interconnection state or in the disconnection state based on the values of the voltages V pn and V ng . Whether the power conditioner 2 is in the interconnection state or in the disconnection state may be determined by the values of the voltages V pn and V pg instead of the voltages V pn and V ng . In the first and second embodiments, the configuration example for displaying various information on the display device 48 provided in the ground fault detection devices 4 and 4A has been described, but the outside provided outside the ground fault detection devices 4 and 4A Various types of information related to the ground fault detection devices 4 and 4A may be displayed on the display device.

また実施の形態１，２の表示装置４８の表示内容は、地絡検出装置４，４Ａの動作状態情報、パワーコンディショナ２の連系状態情報に限定されるものではない。例えば地絡検出部４７，４７Ａは、連系状態判定部４７ｃで解列状態であると判定された場合には第１の地絡検出部４７ａで検出された地絡の検出結果、または第３の地絡検出部４７ｄで検出された地絡の検出結果を出力し、連系状態判定部４７ｃで連系状態であると判定された場合には第２の地絡検出部４７ｂで検出された地絡の検出結果を出力するように構成される。そして、表示装置４８は、地絡検出装置４，４Ａの動作状態を示す情報と、パワーコンディショナ２が駅舎内電路系統５と解列状態にあるか連系状態にあるかを示す情報と、第１の地絡検出部４７ａで検出された地絡の検出結果を示す情報と、第２の地絡検出部４７ｂで検出された地絡の検出結果を示す情報と、第３の地絡検出部４７ｄで検出された地絡の検出結果を示す情報との何れかを表示する。このように構成すれば、ユーザは地絡検出装置４，４Ａの動作状態、パワーコンディショナ２の連系状態、または地絡の発生の有無を、容易に把握することができる。特に実施の形態２の地絡検出装置４Ａの第３の地絡検出部４７ｄは、例えば複数の直流回路の内、地絡が発生した直流回路を識別する情報に、地絡の検出結果を示す情報を対応付けて出力する構成とすれば、ユーザは地絡が発生した直流回路を特定することができ、保守の容易化を図ることができる。   Further, the display contents of the display device 48 according to the first and second embodiments are not limited to the operation state information of the ground fault detection devices 4 and 4A and the interconnection state information of the power conditioner 2. For example, when the ground connection detecting unit 47, 47A determines that the connection state determining unit 47c is in the disconnection state, the detection result of the ground from the first ground detecting unit 47a, or the third The detection result of the ground fault detected by the ground fault detection unit 47 d is output, and when it is determined by the interconnection state determination unit 47 c that the interconnection state is present, the second ground fault detection unit 47 b detects It is configured to output a ground fault detection result. Then, the display device 48 includes information indicating the operation state of the ground fault detection devices 4 and 4A, and information indicating whether the power conditioner 2 is in the disconnection state or in the interconnection state with the station electrical circuit system 5; Information indicating the detection result of the ground fault detected by the first ground fault detection unit 47a, information indicating the detection result of the ground fault detected by the second ground fault detection unit 47b, and the third ground fault detection Any one of the information indicating the detection result of the ground fault detected by the unit 47 d is displayed. According to this configuration, the user can easily grasp the operation state of the ground fault detection devices 4 and 4A, the connection state of the power conditioner 2, or the presence or absence of the occurrence of the ground fault. In particular, the third ground fault detection unit 47d of the ground fault detection device 4A according to the second embodiment indicates the detection result of the ground fault in the information identifying the DC circuit in which the ground fault has occurred among the plurality of DC circuits, for example. If the information is output in association with the information, the user can specify the DC circuit in which the ground fault has occurred, and the maintenance can be facilitated.

以上に説明したように実施の形態１，２の地絡検出装置は、太陽光発電システムの直流回路の正極側電源線と直流回路の負極側電源線との間で検出された第１の電圧検出値と、正極側電源線と対地間または負極側電源線と対地間の第２の電圧検出値と、正極側電源線と負極側電源線との間に流れる不平衡電流の電流検出値と、を入力として、パワーコンディショナが駅舎内電路系統と解列状態にあるときに直流回路に発生した地絡と、パワーコンディショナが駅舎内電路系統と連系状態にあるときに直流回路に発生した地絡とを検出して出力する地絡検出部を備える。この構成により、パワーコンディショナが連系状態であるか解列状態であるかを判定し、その判定結果に応じた地絡判定を実行することができ、トランスレスで駅舎内電路系統に接続されるパワーコンディショナが駅舎内電路系統と解列状態であるか連系状態であるかに係わらず駅舎補助電源用の太陽光発電システムの直流回路における地絡を精度良く検出することが可能である。   As described above, in the ground fault detection devices according to the first and second embodiments, the first voltage detected between the positive power supply line of the direct current circuit of the solar power generation system and the negative power supply line of the direct current circuit. A detection value, a second voltage detection value between the positive power supply line and the ground or between the negative power supply line and the ground, and a current detection value of an unbalanced current flowing between the positive power supply line and the negative power supply line; , As an input, a ground fault generated in the DC circuit when the power conditioner is in a disconnection state with the station electrical circuit system, and a DC circuit when the power conditioner is in an interconnection state with the station electrical path system A ground fault detection unit is provided which detects and outputs the detected ground fault. With this configuration, it can be determined whether the power conditioner is in the interconnection state or in the disconnection state, and ground fault determination can be performed according to the determination result, and can be connected to the in-station electrical circuit system without transformer. It is possible to accurately detect a ground fault in the DC circuit of a photovoltaic power generation system for station building auxiliary power regardless of whether the power conditioner in the station building is disconnected or interconnected .

また実施の形態１，２の地絡検出装置において、正極側電源線と対地間または負極側電源線と対地間に、電圧検出用地絡抵抗を接続する第１のスイッチを備え、連系状態判定部は、電圧検出用地絡抵抗に印加される電圧を第２の電圧検出値として、パワーコンディショナが駅舎内電路系統と解列状態にあるか連系状態にあるかを判定し、第１の地絡検出部は、電圧検出用地絡抵抗に印加される電圧を第２の電圧検出値として、直流回路に発生した地絡を検出する構成である。この構成により、正極側電源線と対地間の電圧を測定するための電圧検出用地絡抵抗と、負極側電源線と対地間の電圧を測定するための電圧検出用地絡抵抗とを個別に設けることなく、電圧検出用地絡抵抗に印加される電圧で地絡を検出することができ、回路が簡素化され、コストの増加を抑制しながら太陽光発電システムの直流回路における地絡を精度良く検出することが可能である。   In the ground fault detecting apparatus according to the first and second embodiments, the first switch for connecting a ground fault resistance for voltage detection between the positive power supply line and the ground or between the negative power supply line and the ground is provided. The unit determines, using the voltage applied to the voltage detection ground fault resistance as a second voltage detection value, whether the power conditioner is in a disconnection state or in an interconnection state with the station electrical circuit system, and the first The ground fault detection unit is configured to detect a ground fault generated in the DC circuit, using a voltage applied to the voltage detection ground fault resistor as a second voltage detection value. With this configuration, the voltage detection ground fault resistance for measuring the voltage between the positive side power supply line and the ground, and the voltage detection ground fault resistance for measuring the voltage between the negative side power supply line and the ground are provided separately. Instead, the ground fault can be detected by the voltage applied to the ground fault resistance for voltage detection, the circuit is simplified, and the ground fault in the DC circuit of the solar power generation system is accurately detected while suppressing the increase in cost. It is possible.

また実施の形態２の地絡検出システムは、複数の太陽電池の各々に接続された直流回路の各々に設置され、複数の直流回路の正極側電源線と負極側電源線との間に流れる不平衡電流を検出して電流検出値として出力する電流検出器を複数備えると共に、第１のスイッチを介して、正極側電源線と対地間または負極側電源線と対地間に接続される電流検出用地絡抵抗と、第１のスイッチに電圧検出用地絡抵抗が接続されているときには、第１のスイッチに電流検出用地絡抵抗を接続せず、第１のスイッチに電流検出用地絡抵抗が接続されているときには、第１のスイッチに電圧検出用地絡抵抗を接続しない第２のスイッチと、を備え、地絡検出部は、正極側電源線と対地間または負極側電源線と対地間に電流検出用地絡抵抗を接続したときに複数の電流検出器の各々で検出された電流検出値と第１の電圧検出値に基づいて、複数の直流回路の各々で発生した地絡を検出する第３の地絡検出部を備える。この構成により、複数の太陽電池の各々に接続された直流回路がパワーコンディショナに接続されている場合でも、システムのコストアップを招くことなく、パワーコンディショナの解列時における複数の直流回路の各々で発生した地絡を検出することができる。すなわち実施の形態２では、複数の太陽電池１が接続されたパワーコンディショナ２の解列時における地絡検出の精度を向上させることができる。   In addition, the ground fault detection system according to the second embodiment is installed in each of the DC circuits connected to each of the plurality of solar cells, and flows between the positive power supply line and the negative power supply line of the plurality of DC circuits. A plurality of current detectors for detecting an equilibrium current and outputting it as a current detection value, and a current detection ground connected between the positive power supply line and the ground or between the negative power supply line and the ground via the first switch When the voltage detection ground fault resistance is connected to the first resistance switch and the first switch, the current detection ground fault resistance is connected to the first switch without connecting the current detection ground fault resistance to the first switch. And a second switch not connecting the voltage detection ground fault resistance to the first switch, and the ground fault detection unit is configured to detect the current ground between the positive power supply line and the ground or between the negative power supply line and the ground. When connecting the resistance Based current detection values detected by the respective current detectors and the first voltage detection value, and a third ground fault detector for detecting a ground fault generated in each of the plurality of DC circuits. With this configuration, even when the DC circuit connected to each of the plurality of solar cells is connected to the power conditioner, the cost of the system is not increased, and the plurality of DC circuits at the time of disconnection of the power conditioner The ground fault generated in each can be detected. That is, in the second embodiment, it is possible to improve the accuracy of the ground fault detection at the time of disconnection of the power conditioner 2 to which the plurality of solar cells 1 are connected.

以上の実施の形態に示した構成は、本発明の内容の一例を示すものであり、別の公知の技術と組み合わせることも可能であるし、本発明の要旨を逸脱しない範囲で、構成の一部を省略、変更することも可能である。   The configuration shown in the above embodiment shows an example of the contents of the present invention, and can be combined with another known technique, and one of the configurations is possible within the scope of the present invention. Parts can be omitted or changed.

１ 太陽電池、２ パワーコンディショナ、３ 直流回路、４，４Ａ 駅舎補助電源用地絡検出装置、５ 駅舎内電路系統、２１ インバータ回路、２２ 連系リレー、３１ 正極側電源線、３２ 負極側電源線、３３，３４，３５，３６，３７，３８ 対地絶縁抵抗、４１ 零相変流器、４２ 第１の電圧検出部、４３ 電圧検出用地絡抵抗、４４ 第１のスイッチ、４５ 第２の電圧検出部、４６ ＡＤ変換部、４７ 地絡検出部、４７Ａ 地絡検出部、４７ａ 第１の地絡検出部、４７ｂ 第２の地絡検出部、４７ｃ 連系状態判定部、４７ｄ 第３の地絡検出部、４８ 表示装置、４９ 電流検出用地絡抵抗、５０ 第２のスイッチ、１００，１００Ａ 地絡検出システム。   DESCRIPTION OF SYMBOLS 1 solar cell, 2 power conditioner, 3 direct current circuit, 4,4A station building auxiliary power ground fault detection device, 5 station electric circuit system, 21 inverter circuit, 22 interconnection relay, 31 positive side power supply line, 32 negative side power supply line , 33, 34, 35, 36, 37, 38 Ground insulation resistance, 41 zero-phase current transformer, 42 first voltage detection unit, 43 voltage detection ground fault resistance, 44 first switch, 45 second voltage detection 46 AD conversion unit 47 ground fault detection unit 47A ground fault detection unit 47a first ground fault detection unit 47b second ground fault detection unit 47c connection state determination unit 47d third ground fault Detection unit, 48 display devices, 49 ground fault resistance for current detection, 50 second switch, 100, 100A ground fault detection system.

Claims (6)

太陽電池と、前記太陽電池からの電力を駅舎内電路系統へ供給し、前記駅舎内電路系統とトランスレスで接続されるパワーコンディショナと、
前記太陽電池から出力される電力をパワーコンディショナへ供給する直流回路と、
前記パワーコンディショナと前記太陽電池との間に設けられる直流回路の地絡を検出する駅舎補助電源用地絡検出装置とを備えた地絡検出システムにおいて用いられる駅舎補助電源用地絡検出装置であって、
前記駅舎補助電源用地絡検出装置は、前記直流回路の正極側電源線と前記直流回路の負極側電源線との間で検出された第１の電圧検出値と、前記正極側電源線と対地間または前記負極側電源線と対地間の第２の電圧検出値と、前記正極側電源線と前記負極側電源線との間に流れる不平衡電流の電流検出値と、を入力として、前記パワーコンディショナが前記駅舎内電路系統と解列状態にあるときに前記直流回路に発生した地絡と、前記パワーコンディショナが前記駅舎内電路系統と連系状態にあるときに前記直流回路に発生した地絡とを検出する地絡検出部を備え、
前記地絡検出部は、
前記第１の電圧検出値と前記第２の電圧検出値とに基づいて前記パワーコンディショナが前記駅舎内電路系統と解列状態にあるか連系状態にあるかを判定する連系状態判定部と、
前記第１の電圧検出値と前記第２の電圧検出値とに基づいて前記直流回路に発生した地絡を検出する第１の地絡検出部と、
前記電流検出値に基づいて前記直流回路に発生した地絡を検出する第２の地絡検出部と、
を備えたことを特徴とする駅舎補助電源用地絡検出装置。 A solar battery, and a power conditioner that supplies power from the solar battery to a station electrical circuit system and is connected to the station electrical circuit system by transformerlessly;
A direct current circuit for supplying a power conditioner with power output from the solar cell;
It is a ground fault detection device for a station auxiliary power source used in a ground fault detection system including a station building auxiliary power ground fault detection device for detecting a ground fault in a DC circuit provided between the power conditioner and the solar cell, ,
The station building auxiliary power ground fault detection device includes: a first voltage detection value detected between a positive power supply line of the DC circuit and a negative power supply line of the DC circuit; Alternatively, the power condition may be input using a second voltage detection value between the negative side power supply line and the ground, and a current detection value of an unbalanced current flowing between the positive side power supply line and the negative side power supply line. A ground fault generated in the DC circuit when the power supply system is disconnected from the station electrical system, and a ground generated in the DC circuit when the power conditioner is connected to the station electrical circuit system equipped with a ground fault detection unit that detects a fault,
The ground fault detection unit
Interconnection state determination unit that determines whether the power conditioner is in a disconnection state or in an interconnection state with the station electrical path system based on the first voltage detection value and the second voltage detection value When,
A first ground fault detection unit that detects a ground fault generated in the DC circuit based on the first voltage detection value and the second voltage detection value;
A second ground fault detection unit that detects a ground fault generated in the DC circuit based on the current detection value;
A ground fault detection device for a station building auxiliary power supply comprising: 前記第１の地絡検出部は、前記第１の電圧検出値と前記第２の電圧検出値とに基づいて前記直流回路の絶縁抵抗値を算出して前記直流回路に発生した地絡を検出することを特徴とする請求項１に記載の駅舎補助電源用地絡検出装置。 The first ground fault detection unit calculates an insulation resistance value of the DC circuit based on the first voltage detection value and the second voltage detection value to detect a ground fault generated in the DC circuit. The ground fault detection apparatus for station building auxiliary power according to claim 1 , wherein: 前記正極側電源線と対地間または前記負極側電源線と対地間に、電圧検出用地絡抵抗を接続する第１のスイッチを備え、
前記連系状態判定部は、前記電圧検出用地絡抵抗に印加される電圧を前記第２の電圧検出値として、前記パワーコンディショナが前記駅舎内電路系統と解列状態にあるか連系状態にあるかを判定し、
前記第１の地絡検出部は、前記電圧検出用地絡抵抗に印加される電圧を前記第２の電圧検出値として、前記直流回路に発生した地絡を検出することを特徴とする請求項１に記載の駅舎補助電源用地絡検出装置。 A first switch is connected between the positive power supply line and the ground, or between the negative power supply line and the ground, for connecting a ground terminal for voltage detection.
The interconnection state determination unit determines whether the power conditioner is in a disconnection state or an interconnection state with the electric line system in the station building, using the voltage applied to the voltage detection ground fault resistance as the second voltage detection value. Determine if there is,
The first earth fault detection unit, according to claim, characterized in that the voltage applied to the voltage detection site fault resistance as said second voltage detection value to detect a ground fault generated in the DC circuit 1 The station building auxiliary power source ground fault detection device according to. 前記地絡検出システムは、
複数の太陽電池の各々に接続された直流回路の各々に設置され、複数の前記直流回路の正極側電源線と負極側電源線との間に流れる不平衡電流を検出して電流検出値として出力する電流検出器を複数備えると共に、
前記第１のスイッチを介して、前記正極側電源線と対地間または前記負極側電源線と対地間に接続される電流検出用地絡抵抗と、
前記第１のスイッチに前記電圧検出用地絡抵抗が接続されているときには、前記第１のスイッチに前記電流検出用地絡抵抗を接続せず、前記第１のスイッチに前記電流検出用地絡抵抗が接続されているときには、前記第１のスイッチに前記電圧検出用地絡抵抗を接続しない第２のスイッチと、
を備え、
前記地絡検出部は、前記正極側電源線と対地間または前記負極側電源線と対地間に前記電流検出用地絡抵抗を接続したときに複数の前記電流検出器の各々で検出された電流検出値と前記第１の電圧検出値とに基づいて、複数の前記直流回路の各々で発生した地絡を検出する第３の地絡検出部を備えたことを特徴とする請求項３に記載の駅舎補助電源用地絡検出装置。 The ground fault detection system
It is installed in each of the DC circuits connected to each of the plurality of solar cells, detects an unbalanced current flowing between the positive power supply line and the negative power supply line of the plurality of DC circuits, and outputs it as a current detection value With multiple current detectors,
A current detection ground fault resistor connected between the positive power supply line and the ground or between the negative power supply line and the ground via the first switch;
When the voltage detection ground fault resistance is connected to the first switch, the current detection ground fault resistance is not connected to the first switch, and the current detection ground fault resistance is connected to the first switch. A second switch that does not connect the voltage detection ground fault resistor to the first switch when the second switch is turned on;
Equipped with
The ground detection unit detects a current detected by each of the plurality of current detectors when the ground terminal for current detection is connected between the positive power supply line and the ground or between the negative power supply line and the ground. 4. A third ground fault detection unit for detecting a ground fault generated in each of the plurality of direct current circuits based on a value and the first voltage detection value according to claim 3 . Station building auxiliary power source ground fault detection device. 前記地絡検出部は、前記第１の地絡検出部で検出された地絡の検出結果を示す情報と、前記第２の地絡検出部で検出された地絡の検出結果を示す情報と、前記第３の地絡検出部で検出された地絡の検出結果を示す情報との何れかを、表示装置に出力することを特徴とする請求項４に記載の駅舎補助電源用地絡検出装置。 The ground fault detection unit includes information indicating a ground fault detection result detected by the first ground fault detection unit, and information indicating a ground fault detection result detected by the second ground fault detection unit. The ground fault detection device for a station auxiliary power supply according to claim 4 , wherein any one of information indicating a detection result of the ground fault detected by the third ground fault detection unit is output to a display device. . 前記第３の地絡検出部は、複数の前記直流回路の内、地絡が発生した直流回路を識別する情報に前記地絡の検出結果を示す情報を対応付けて出力することを特徴とする請求項５に記載の駅舎補助電源用地絡検出装置。 The third ground fault detection unit is characterized in that the information indicating the detection result of the ground fault is associated with the information identifying the DC circuit in which the ground fault has occurred among the plurality of DC circuits, and is output. A ground fault detection device for a station building auxiliary power supply according to claim 5 .
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