JP2022084949A - Ior ground point current detection soft integrated ground current inhibition system - Google Patents

Ior ground point current detection soft integrated ground current inhibition system Download PDF

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JP2022084949A
JP2022084949A JP2022062339A JP2022062339A JP2022084949A JP 2022084949 A JP2022084949 A JP 2022084949A JP 2022062339 A JP2022062339 A JP 2022062339A JP 2022062339 A JP2022062339 A JP 2022062339A JP 2022084949 A JP2022084949 A JP 2022084949A
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ground fault
ground
ior
phase
changeover switch
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JP2022084949A5 (en
JP7493724B2 (en
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正美 鈴木
Masami Suzuki
祐輔 篠崎
Yusuke Shinozaki
一彦 古屋
Kazuhiko Furuya
頼数 頭本
Yorikazu Kashiramoto
達哉 茂木
Tatsuya Mogi
佳樹 井上
Yoshiki Inoue
俊一 柳川
Shunichi Yanagawa
貴矩 登野城
Takanori Tonoshiro
龍三 野田
Ryuzo Noda
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KANTO ELECTRICAL SAFETY INSPECTION ASSOCIATION
So Brain Co Ltd
Sobrain
Kandenko Co Ltd
Shoden Corp
CDN Corp
Satori Electric Co Ltd
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KANTO ELECTRICAL SAFETY INSPECTION ASSOCIATION
So Brain Co Ltd
Sobrain
Kandenko Co Ltd
Shoden Corp
CDN Corp
Satori Electric Co Ltd
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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
    • Y04—INFORMATION OR COMMUNICATION TECHNOLOGIES HAVING AN IMPACT ON OTHER TECHNOLOGY AREAS
    • Y04S—SYSTEMS INTEGRATING TECHNOLOGIES RELATED TO POWER NETWORK OPERATION, COMMUNICATION OR INFORMATION TECHNOLOGIES FOR IMPROVING THE ELECTRICAL POWER GENERATION, TRANSMISSION, DISTRIBUTION, MANAGEMENT OR USAGE, i.e. SMART GRIDS
    • Y04S10/00—Systems supporting electrical power generation, transmission or distribution
    • Y04S10/50—Systems or methods supporting the power network operation or management, involving a certain degree of interaction with the load-side end user applications
    • Y04S10/52—Outage or fault management, e.g. fault detection or location

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Abstract

PROBLEM TO BE SOLVED: To provide an Ior ground point current detection soft integrated ground current inhibition system capable of detecting Ior without being affected by the frequency and the like generated by a VVVF inverter control.
SOLUTION: An Ior ground point current detection soft integrated ground current inhibition system is provided in a B kind ground line, and includes: a ground current control part 11 configured by connecting in parallel a control resistor 11a and a change-over switch 11b for switching both ends of the control resistor 11a to open or close; a calculation part for calculating Ior based on Io; and a control part for opening the changeover switch 11b to control the ground state to the ground suppression state when it is determined that Ior continues for a predetermined time and exceeds the first threshold value. A calculation part calculates an assumption Io and an assumption Ior, assuming that the change-over switch 11b is in a blocked state in the case that the change-over switch 11b is opened and in a ground control state. When the control part determines that the assumption Ior continues for a predetermined time and is below the second threshold value, the change-over switch 11b is blocked.
SELECTED DRAWING: Figure 1
COPYRIGHT: (C)2022,JPO&INPIT

Description

本発明は、地絡電流を抑制するＩｏｒ地絡点電流検出ソフト組込型地絡電流抑制システムに関する。 The present invention relates to an Ior ground fault point current detection software built-in ground fault current suppression system that suppresses ground fault current.

電気設備の負荷機器を含む電気系統の絶縁性能は、感電、火災等の防止上、非常に重要であるが、電気設備の経年劣化や工事等により絶縁性能が損なわれ、電路に漏洩電流（以下、「Ｉｏ」という。）が発生することがある。Ｉｏの発生を予兆したり、または、実際に発生しているＩｏを検知して、事故を未然に、または、早い段階で防止することが重要である。 The insulation performance of the electrical system including the load equipment of the electrical equipment is very important for the prevention of electric shock, fire, etc., but the insulation performance is impaired due to aging deterioration of the electrical equipment and construction work, etc. , "Io") may occur. It is important to predict the occurrence of Io or detect the actual occurrence of Io to prevent accidents in advance or at an early stage.

このため、受電変圧器には、二次側の回路の接地線にＩｏを監視する絶縁監視装置を設けるようにしている。ここで、Ｉｏには、対地静電容量に起因する漏洩電流（以下、「Ｉｏｃ」という。）と、絶縁抵抗に直接関与している対地絶縁抵抗に起因する漏洩電流（以下、「Ｉｏｒ」という。）とが含まれている。 Therefore, the power receiving transformer is provided with an insulation monitoring device for monitoring Io on the ground wire of the circuit on the secondary side. Here, Io refers to a leakage current due to the capacitance to ground (hereinafter referred to as “Ioc”) and a leakage current due to the insulation resistance to ground that is directly related to the insulation resistance (hereinafter referred to as “Ior”). .) And is included.

例えば、特許文献１では、Ｂ種接地線に抑制抵抗を介置し、漏電電流を検出する絶縁監視装置の構成が開示されている。具体的には、当該絶縁監視装置では、変圧器の二次側回路に漏電が発生して二次側電線の地絡抵抗が閾値抵抗よりも小さくなった場合には、切替スイッチを開放することにより、Ｂ種接地線に抑制抵抗が介置された状態とし、二次側電線に一線地絡が生じたものと判断し、かつ、各二次側電線とグランドとの間の静電容量が同一であると仮定して、一線地絡による漏電電流を算出する。 For example, Patent Document 1 discloses a configuration of an insulation monitoring device that detects a leakage current by inserting a suppression resistance in a class B ground wire. Specifically, in the insulation monitoring device, when an electric leakage occurs in the secondary circuit of the transformer and the ground fault resistance of the secondary wire becomes smaller than the threshold resistance, the changeover switch is opened. Therefore, it is judged that a one-wire ground fault has occurred in the secondary side electric wire, and the capacitance between each secondary side electric wire and the ground is increased. Assuming that they are the same, the leakage current due to a one-wire ground fault is calculated.

特開２０１５－２０６７４１号公報Japanese Unexamined Patent Publication No. 2015-206741

しかしながら、特許文献１では、Ｂ種接地線に絶縁監視用の信号として商用周波数（５０Ｈz、６０Ｈz）とは異なる特定周波数（例えば、２０Ｈz）を注入することによりＩｏを測定する構成であり、この特定周波数と、負荷に使用する電動機によるＶＶＶＦ（Ｖａｒｉａｂｌｅ Ｖｏｌｔａｇｅ Ｖａｒｉａｂｌｅ Ｆｒｅｑｕｅｎｃｙ）インバータ制御によって発生する周波数や、電路の対地静電容量が増加することにより発生する低次高調波とが同程度になると、Ｉｏの測定が困難になる。 However, Patent Document 1 has a configuration in which Io is measured by injecting a specific frequency (for example, 20 Hz) different from the commercial frequency (50 Hz, 60 Hz) as a signal for insulation monitoring into the class B ground wire. When the frequency and the frequency generated by the VVVF (Variable Voltage Variable Frequency) inverter control by the electric motor used for the load and the low-order harmonic generated by the increase in the electrostatic capacitance to the ground of the electric circuit become similar, the Io Measurement becomes difficult.

本開示では、ＶＶＶＦインバータ制御により発生する周波数や電路の対地静電容量が増加することにより発生する低次高調波に影響されずにＩｏｒを検出することができるＩｏｒ地絡点電流検出ソフト組込型地絡電流抑制システムを提供することを目的とする。 In the present disclosure, Ior ground fault point current detection software that can detect Ior without being affected by low-order harmonics generated by increasing the frequency generated by VVVF inverter control and the capacitance to ground of the electric circuit is incorporated. It is an object of the present invention to provide a type ground fault current suppression system.

上記目的を達成するために、本発明の一態様におけるＩｏｒ地絡点電流検出ソフト組込型地絡電流抑制システムは、変圧器のＢ種接地線に設けられ、抑制抵抗と、当該抑制抵抗の両端を開放または閉塞を切り替える切替スイッチとが並列接続されて構成される地絡電流抑制部と、前記Ｂ種接地線に流れる漏洩電流を検出する漏洩電流検出部と、前記漏洩電流検出部で検出した漏洩電流に基づいて、対地絶縁抵抗に起因する漏洩電流を算出する算出部と、前記算出部により算出した対地絶縁抵抗に起因する漏洩電流が所定時間継続して第１閾値を超えているかどうかを判断し、対地絶縁抵抗に起因する漏洩電流が所定時間継続して第１閾値を超えていると判断した場合、前記切替スイッチを開放して地絡抑制状態に制御する制御部とを備え、前記算出部は、前記切替スイッチが開放されて地絡抑制状態になった場合、前記切替スイッチが閉塞されている状態を想定して、想定漏洩電流と、対地絶縁抵抗に起因する想定漏洩電流を算出し、前記制御部は、前記算出部により算出した対地絶縁抵抗に起因する想定漏洩電流が所定時間継続して第２閾値を下まわっているかどうかを判断し、対地絶縁抵抗に起因する想定漏洩電流が所定時間継続して第２閾値を下まわっていると判断した場合、前記切替スイッチを閉塞して地絡抑制状態を解除する。 In order to achieve the above object, the Ior ground fault point current detection software built-in type ground fault current suppression system according to one aspect of the present invention is provided on the class B ground wire of the transformer, and has a suppression resistance and the suppression resistance. A ground fault current suppression unit configured by connecting a changeover switch that switches between open and closed ends in parallel, a leakage current detection unit that detects the leakage current flowing through the class B ground wire, and a leakage current detection unit that detects the leakage current. Whether or not the calculation unit that calculates the leakage current due to the insulation resistance to ground based on the leakage current and the leakage current due to the insulation resistance to ground calculated by the calculation unit continuously exceeds the first threshold value for a predetermined time. When it is determined that the leakage current due to the insulation resistance to the ground continuously exceeds the first threshold value for a predetermined time, the changeover switch is opened to provide a control unit for controlling the ground fault suppression state. When the changeover switch is opened and the ground fault is suppressed, the calculation unit calculates the assumed leakage current and the assumed leakage current due to the insulation resistance to the ground, assuming that the changeover switch is closed. The control unit determines whether or not the assumed leakage current due to the ground insulation resistance calculated by the calculation unit continues to fall below the second threshold value for a predetermined time, and the control unit determines whether or not the assumed leakage current due to the ground insulation resistance continues to fall below the second threshold value. When it is determined that the current continues to fall below the second threshold value for a predetermined time, the changeover switch is closed to release the ground fault suppression state.

本発明によれば、ＶＶＶＦインバータ制御により発生する周波数や電路の対地静電容量が増加することにより発生する低次高調波に影響されずにＩｏｒを検出することができる。 According to the present invention, Ior can be detected without being affected by low-order harmonics generated by increasing the frequency generated by VVVF inverter control and the capacitance to ground of the electric circuit.

Ｉｏｒ地絡点電流検出ソフト組込型地絡電流抑制システムの第１の構成を示す図である。It is a figure which shows the 1st configuration of the Ior ground fault point current detection software embedded type ground fault current suppression system. 絶縁監視装置の構成を示す図である。It is a figure which shows the structure of the insulation monitoring apparatus. Ｒ相とＴ相に発生するＩｏｃについての説明に供する図である。It is a figure which provides the explanation about Ioc which occurs in R phase and T phase. Ｔ相に地絡が発生した場合におけるＩｏとＩｏｒとの関係についての説明に供する図である。It is a figure which provides the explanation about the relationship between Io and Ior when the ground fault occurs in the T phase. Ｒ相に地絡が発生した場合におけるＩｏとＩｏｒとの関係についての説明に供する図である。It is a figure which provides the explanation about the relationship between Io and Ior when the ground fault occurs in the R phase. 変動範囲に基づいて地絡した相を特定する説明に供する図である。It is a figure which provides the explanation to identify the phase of the ground fault based on the fluctuation range. 地絡が発生していない場合におけるＩｏｒ地絡点電流検出ソフト組込型地絡電流抑制システムの動作についての説明に供するフローチャートである。It is a flowchart which provides the explanation about the operation of the Ior ground fault point current detection software built-in type ground fault current suppression system when the ground fault does not occur. 漏電が生じていない場合における解法時の等価回路である。This is an equivalent circuit at the time of solution when no electric leakage has occurred. 地絡が発生している場合におけるＩｏｒ地絡点電流検出ソフト組込型地絡電流抑制システムの動作についての説明に供するフローチャートである。It is a flowchart which provides the explanation about the operation of the Ior ground fault point current detection software built-in type ground fault current suppression system when the ground fault occurs. 切替スイッチが開放状態の場合におけるＩｏｒ地絡点電流検出ソフト組込型地絡電流抑制システムの構成を示す図である。It is a figure which shows the structure of the Ior ground fault point current detection software embedded type ground fault current suppression system when the changeover switch is open state. Ｉｏｒ地絡点電流検出ソフト組込型地絡電流抑制システムの第２の構成を示す図である。It is a figure which shows the 2nd configuration of the Ior ground fault point current detection software embedded type ground fault current suppression system. 地絡が発生していない場合におけるＩｏｒ地絡点電流検出ソフト組込型地絡電流抑制システムの動作についての説明に供するフローチャートである。It is a flowchart which provides the explanation about the operation of the Ior ground fault point current detection software built-in type ground fault current suppression system when the ground fault does not occur. 漏電が生じている場合における解法時の第１の等価回路である。This is the first equivalent circuit at the time of solution when an electric leakage occurs. 地絡が発生している場合におけるＩｏｒ地絡点電流検出ソフト組込型地絡電流抑制システムの動作についての説明に供するフローチャートである。It is a flowchart which provides the explanation about the operation of the Ior ground fault point current detection software built-in type ground fault current suppression system when the ground fault occurs. 切替スイッチが開放状態の場合におけるＩｏｒ地絡点電流検出ソフト組込型地絡電流抑制システムの構成を示す図である。It is a figure which shows the structure of the Ior ground fault point current detection software embedded type ground fault current suppression system when the changeover switch is open state. 漏電が生じている場合における解法時の第２の等価回路である。This is the second equivalent circuit at the time of solution in the case of electric leakage.

以下、本実施形態について説明する。なお、以下に説明する本実施形態は、特許請求の範囲に記載された本発明の内容を不当に限定するものではない。また、本実施形態で説明される構成の全てが、本発明の必須構成要件であるとは限らない。 Hereinafter, the present embodiment will be described. It should be noted that the present embodiment described below does not unreasonably limit the content of the present invention described in the claims. Moreover, not all of the configurations described in the present embodiment are essential constituent requirements of the present invention.

＜第１実施形態＞
Ｉｏｒ地絡点電流検出ソフト組込型地絡電流抑制システム１は、Ｉｏｒ地絡点の電流を検出するソフトにより地絡電流を抑制する機能を有しており、図１に示すように、変圧器１０と、地絡電流抑制部１１と、漏洩電流検出部１２と、絶縁監視装置１３とを備える。図１には、変圧器１０の二次側が示されている。第１実施形態においては、変圧器１０の二次側は、Ｒ相、Ｓ相、Ｔ相の３相デルタ結線であり、このうち１つの相（Ｓ相）に接続される電線をＢ種接地線とし、他の２つの相（Ｒ相とＴ相）に接続される電線を活線である場合を例示して説明する。 <First Embodiment>
Ior ground fault current detection software The built-in ground fault current suppression system 1 has a function to suppress the ground fault current by the software that detects the current at the Ior ground fault point, and as shown in FIG. 1, it is transformed. A device 10, a ground fault current suppressing unit 11, a leakage current detecting unit 12, and an insulation monitoring device 13 are provided. FIG. 1 shows the secondary side of the transformer 10. In the first embodiment, the secondary side of the transformer 10 is a three-phase delta connection of R phase, S phase, and T phase, and the electric wire connected to one of the phases (S phase) is grounded in class B. An example will be described in which a wire is used and an electric wire connected to the other two phases (R phase and T phase) is a live wire.

また、Ｒｒは、Ｒ相に地絡が生じた場合における対地絶縁抵抗（地絡抵抗）を示し、Ｉｏｒ（ｒ）は、Ｒ相の対地絶縁抵抗に起因する漏洩電流を示し、Ｃｒは、Ｒ相の配線浮遊容量を示し、Ｉｏｃ（ｒ）は、Ｒ相の対地静電容量に起因する漏洩電流を示している。また、図１中のＲｔは、Ｔ相に地絡が生じた場合における対地絶縁抵抗（地絡抵抗）を示し、Ｉｏｒ（ｔ）は、対地絶縁抵抗に起因する漏洩電流を示し、Ｃｔは、Ｔ相の配線浮遊容量を示し、Ｉｏｃ（ｔ）は、Ｔ相の対地静電容量に起因する漏洩電流を示している。 Further, Rr indicates the ground insulation resistance (ground fault resistance) when a ground fault occurs in the R phase, Ior (r) indicates the leakage current due to the ground insulation resistance of the R phase, and Cr indicates R. The phase wiring stray capacitance is shown, and Ioc (r) shows the leakage current due to the ground capacitance of the R phase. Further, Rt in FIG. 1 indicates the ground insulation resistance (ground fault resistance) when a ground fault occurs in the T phase, Ior (t) indicates the leakage current due to the ground insulation resistance, and Ct indicates the leakage current. The wiring stray capacitance of the T phase is shown, and Ioc (t) shows the leakage current due to the capacitance to ground of the T phase.

＜地絡電流抑制部の構成について＞
地絡電流抑制部１１は、変圧器１０のＢ種接地線に設けられ、抑制抵抗１１ａと、切替スイッチ１１ｂと、保護回路１１ｃとが並列接続されて構成される。 <About the configuration of the ground fault current suppression unit>
The ground fault current suppression unit 11 is provided on the class B ground wire of the transformer 10, and is configured by connecting the suppression resistance 11a, the changeover switch 11b, and the protection circuit 11c in parallel.

抑制抵抗１１ａは、所定の抵抗値（例えば、２ｋΩなど）であり、Ｂ種接地線に流れる電流を抑制する機能を有する。 The suppression resistor 11a has a predetermined resistance value (for example, 2 kΩ or the like), and has a function of suppressing the current flowing through the class B ground wire.

切替スイッチ１１ｂは、詳細は後述するが、制御部１５による制御に応じて、抑制抵抗１１ａの両端を開放または閉塞を切り替える機能を有している。切替スイッチ１１ｂが閉塞している場合には、Ｂ種接地線を流れる電流は、切替スイッチ１１ｂを流れ、抑制抵抗１１ａを流れない。一方、切替スイッチ１１ｂが開放している場合には、Ｂ種接地線を流れる電流は、抑制抵抗１１ａを流れ、抑制される。 Although the details of the changeover switch 11b will be described later, the changeover switch 11b has a function of switching between opening and closing both ends of the suppression resistance 11a according to the control by the control unit 15. When the changeover switch 11b is blocked, the current flowing through the class B ground wire flows through the changeover switch 11b and does not flow through the suppression resistance 11a. On the other hand, when the changeover switch 11b is open, the current flowing through the class B ground wire flows through the suppression resistor 11a and is suppressed.

保護回路１１ｃは、落雷等に起因して変圧器に過大な電圧が加えられ、両端電圧が所定の電圧（例えば、６００Ｖなど）を超えた場合に、両端を短絡して電流を流す機能を有する。 The protection circuit 11c has a function of short-circuiting both ends and passing a current when an excessive voltage is applied to the transformer due to a lightning strike or the like and the voltage across the transformer exceeds a predetermined voltage (for example, 600 V). ..

地絡電流抑制部１１は、通常時は、図１に示すように、切替スイッチ１１ｂが閉塞（ノーマリークローズ）しており、抑制抵抗１１ａに電流が流れない構成になっている。 As shown in FIG. 1, the ground fault current suppressing unit 11 is normally configured such that the changeover switch 11b is closed (normally closed) and no current flows through the suppression resistance 11a.

漏洩電流検出部１２は、例えば、零相変流器（ＺＣＴ）により構成されており、Ｂ種接地線に流れる漏洩電流を検出する。 The leakage current detection unit 12 is composed of, for example, a zero-phase current transformer (ZCT), and detects the leakage current flowing through the class B ground wire.

絶縁監視装置１３は、変圧器１０の二次側における絶縁監視を行う装置である。特に、絶縁監視装置１３は、絶縁監視を行うために電線路及び負荷を停電状態にすることなく、かつ、絶縁監視用の信号として商用周波数（５０Ｈz、６０Ｈz）とは異なる特定周波数（例えば、２０Ｈｚ）を注入することなく、監視情報を検出し、検出した監視情報を外部に通知する機能などを有している。 The insulation monitoring device 13 is a device that monitors insulation on the secondary side of the transformer 10. In particular, the insulation monitoring device 13 does not put the electric line and the load into a power failure state for insulation monitoring, and has a specific frequency (for example, 20 Hz) different from the commercial frequency (50 Hz, 60 Hz) as a signal for insulation monitoring. ) Is detected and the detected monitoring information is notified to the outside without injecting).

監視情報には、漏洩電流（以下、「Ｉｏ」という。）や、対地絶縁抵抗に起因する漏洩電流（以下、「Ｉｏｒ」という。）や、対地静電容量に起因する漏洩電流（以下、「Ｉｏｃ」という。）や、位相角度（θ）や、基準電圧や、絶縁抵抗値（Ｇｒ）や、温度などが含まれている。 The monitoring information includes leakage current (hereinafter referred to as "Io"), leakage current due to insulation resistance to ground (hereinafter referred to as "Ior"), and leakage current due to capacitance to ground (hereinafter referred to as "" It is called "Ioc"), the phase angle (θ), the reference voltage, the insulation resistance value (Gr), the temperature, and the like.

Ｉｏは、ＩｏｒとＩｏｃとのベクトル和である。Ｉｏｃは、電線路の長さに応じて容量が増大するだけでなく、負荷に使用されているインバータやノイズフィルター等に起因する高調波歪み電流によっても容量が増大する成分である。Ｉｏｒは、電気火災等を引き起こす原因となる成分である。絶縁監視装置１３は、ＩｏｒをＩｏから正確に算出することができる。また、絶縁監視装置１３は、所定時間間隔（例えば、２５０ｍｓｅｃ）で絶縁監視を行う。 Io is the vector sum of Ior and Ioc. Ioc is a component that not only increases the capacitance according to the length of the electric line, but also increases the capacitance due to the harmonic distortion current caused by the inverter or noise filter used for the load. Ior is a component that causes an electric fire or the like. The insulation monitoring device 13 can accurately calculate Ior from Io. Further, the insulation monitoring device 13 performs insulation monitoring at predetermined time intervals (for example, 250 msec).

＜絶縁監視装置の構成について＞
絶縁監視装置１３は、図２に示すように、算出部１４と、制御部１５とを備える。 <About the configuration of the insulation monitoring device>
As shown in FIG. 2, the insulation monitoring device 13 includes a calculation unit 14 and a control unit 15.

算出部１４は、漏洩電流検出部１２で検出したＩｏに基づいて、位相角度（θ）、Ｉｏｒ、Ｉｏｃなどを算出する。 The calculation unit 14 calculates the phase angle (θ), Ior, Ioc, etc. based on the Io detected by the leakage current detection unit 12.

制御部１５は、算出部１４により算出したＩｏｒが所定時間（例えば、６０秒間）継続して第１閾値（例えば、５０ｍＡ）を超えているかどうかを判断し、Ｉｏｒが所定時間継続して第１閾値を超えていると判断した場合、切替スイッチ１１ｂを開放して地絡抑制状態に制御する。 The control unit 15 determines whether or not the Ior calculated by the calculation unit 14 continuously exceeds the first threshold value (for example, 50 mA) for a predetermined time (for example, 60 seconds), and the Ior continues for a predetermined time for the first time. When it is determined that the threshold value is exceeded, the changeover switch 11b is opened to control the ground fault suppression state.

また、算出部１４は、切替スイッチ１１ｂが開放されて地絡抑制状態になった場合、切替スイッチ１１ｂが閉塞されている状態を想定して、想定される漏洩電流（以下、「想定Ｉｏ」という。）と、対地絶縁抵抗に起因する想定される漏洩電流（以下、「想定Ｉｏｒ」という。）を算出する。 Further, the calculation unit 14 assumes that when the changeover switch 11b is opened and the ground fault is suppressed, the changeover switch 11b is closed, and the assumed leakage current (hereinafter referred to as "assumed Io"). ) And the assumed leakage current due to the insulation resistance to the ground (hereinafter referred to as "assumed Ior") are calculated.

制御部１５は、算出部１４により算出した想定Ｉｏｒが所定時間（例えば、６０秒間）継続して第２閾値（例えば、２０ｍＡ）を下まわっているかどうかを判断し、想定Ｉｏｒが所定時間継続して第２閾値を下まわっていると判断した場合、切替スイッチ１１ｂを閉塞して地絡抑制状態を解除する。 The control unit 15 determines whether or not the assumed Ior calculated by the calculation unit 14 continues to be below the second threshold value (for example, 20 mA) for a predetermined time (for example, 60 seconds), and the assumed Ior continues for a predetermined time. If it is determined that the value is below the second threshold value, the changeover switch 11b is closed to release the ground fault suppression state.

このようにして、本開示のＩｏｒ地絡点電流検出ソフト組込型地絡電流抑制システム１は、切替スイッチ１１ｂが閉塞している状態において、Ｉｏｒが所定時間継続して第１閾値を超えていると判断した場合、切替スイッチ１１ｂを開放して地絡抑制状態に制御し、その後、切替スイッチ１１ｂが閉塞されている状態を想定して、想定Ｉｏｒが所定時間継続して第２閾値を下まわっていると判断した場合、切替スイッチ１１ｂを閉塞して地絡抑制状態を解除するので、Ｉｏｒが所定時間継続して第１閾値を超えた場合に、切替スイッチ１１ｂを開放して抑制抵抗１１ａによりＢ種接地線を流れる電流を抑制し、その後、想定Ｉｏｒが所定時間継続して第２閾値を下まわった場合に、切替スイッチ１１ｂを閉塞して通常状態に素早く戻すことができる。 In this way, in the Ior ground fault current detection software embedded type ground fault current suppression system 1 of the present disclosure, the Ior continuously exceeds the first threshold value for a predetermined time in a state where the changeover switch 11b is closed. If it is determined that the changeover switch 11b is opened to control the ground fault suppression state, then assuming that the changeover switch 11b is closed, the assumed Ior continues to lower the second threshold value for a predetermined time. When it is determined that the current is rotating, the changeover switch 11b is closed to release the ground fault suppression state. Therefore, when the Ior continuously exceeds the first threshold value for a predetermined time, the changeover switch 11b is opened and the suppression resistance 11a is released. Therefore, when the current flowing through the class B ground wire is suppressed and then the assumed Ior continues to fall below the second threshold value for a predetermined time, the changeover switch 11b can be closed and the normal state can be quickly returned.

よって、本開示のＩｏｒ地絡点電流検出ソフト組込型地絡電流抑制システム１は、絶縁監視用の信号として商用周波数とは異なる特定周波数を注入する構成ではないため、ＶＶＶＦインバータ制御により発生する周波数や電路の対地静電容量が増加することにより発生する低次高調波に影響されずにＩｏｒを検出することができる。 Therefore, the Ior ground fault point current detection software built-in type ground fault current suppression system 1 of the present disclosure is not configured to inject a specific frequency different from the commercial frequency as a signal for insulation monitoring, and thus is generated by VVVF inverter control. Ior can be detected without being affected by the low-order harmonics generated by the increase in frequency and the capacitance to ground of the electric circuit.

また、ビルや工場で漏洩電流が検出されると、保守管理を行っている業者に対してアラームが通知されるシステムがある。ところが、休日や深夜などにおいて、漏洩電流が検出され、業者が現場に行っても、担当者が不在のために確認作業を行うことができず、無駄な出動になる場合がある。 In addition, when a leakage current is detected in a building or factory, there is a system that notifies a maintenance company of an alarm. However, on holidays and midnight, leakage current is detected, and even if the contractor goes to the site, the person in charge cannot perform the confirmation work due to the absence of the person in charge, which may result in useless dispatch.

Ｉｏｒ地絡点電流検出ソフト組込型地絡電流抑制システム１では、想定Ｉｏｒが所定時間継続して第２閾値を下まわっていると判断した場合、切替スイッチ１１ｂを閉塞して地絡抑制状態を解除して、通常状態に戻すため、保守管理を行っている業者に対してアラームが通知され続けることがなく、無駄な出動を低減させることができ、効率的な保守管理を行うことができる。 In the Ior ground fault point current detection software built-in type ground fault current suppression system 1, when it is determined that the assumed Ior continues to fall below the second threshold value for a predetermined time, the changeover switch 11b is closed to suppress the ground fault. Since the alarm is not continuously notified to the maintenance management company, unnecessary dispatch can be reduced and efficient maintenance management can be performed. ..

＜事故点の特定について＞
算出部１４では、所定の関数（後述する（１）式）に基づいて、Ｉｏと位相角度（θ）からＩｏｒを算出する。また、算出部１４は、ＩｏとＩｏｒからＩｏｃを算出している。しかし、Ｉｏｒが所定時間継続して第１閾値を超え、切替スイッチ１１ｂが開放され、Ｂ種接地線を流れる電流が抑制抵抗１１ａにより抑制されている状態においては、ＩｏとＩｏｒが同じ値でも、地絡が発生しているのがＴ相であるのか、または、Ｒ相であるのかによって、Ｉｏｃの値が異なる。静的な演算では、どちらの相に地絡が発生しているのか判別できない。 <Identification of accident points>
The calculation unit 14 calculates Ior from Io and the phase angle (θ) based on a predetermined function (formula (1) described later). Further, the calculation unit 14 calculates Ioc from Io and Ior. However, in a state where the Ior continuously exceeds the first threshold value for a predetermined time, the changeover switch 11b is opened, and the current flowing through the class B ground wire is suppressed by the suppression resistance 11a, even if the Io and the Ior have the same value, The value of Ioc differs depending on whether the ground fault occurs in the T phase or the R phase. It is not possible to determine which phase the ground fault is occurring in by static calculation.

本開示のＩｏｒ地絡点電流検出ソフト組込型地絡電流抑制システム１では、Ｉｏｃの変化を監視して、動的な演算を行うことにより、Ｔ相とＲ相のいずれに地絡が生じているのかを特定することができる。 In the Ior ground fault point current detection software embedded type ground fault current suppression system 1 of the present disclosure, a ground fault occurs in either the T phase or the R phase by monitoring the change in Ioc and performing dynamic calculation. It is possible to identify whether it is.

絶縁監視装置１３は、図２に示すように、監視部１６と、地絡特定部１７とを備える。 As shown in FIG. 2, the insulation monitoring device 13 includes a monitoring unit 16 and a ground fault specifying unit 17.

監視部１６は、切替スイッチ１２ｂが閉塞している状態において、接地相以外の相におけるＩｏｃの変化を監視する。 The monitoring unit 16 monitors changes in the Ioc in a phase other than the ground phase while the changeover switch 12b is closed.

ここで、Ｒ相とＴ相に発生するＩｏｃについて、図３から図５を用いて説明する。Ｒ相のＩｏｃ（ｒ）は、Ｒ相から９０度の位置に発生し、Ｔ相のＩｏｃ（ｔ）は、Ｔ相から９０度の位置に発生する。また、Ｉｏｃ（ｒ）の大きさとＩｏｃ（ｔ）の大きさが等しい場合には、ベクトル合成により、Ｉｏｃ（ｒｔ）は、１８０度の位置に発生する。 Here, Ioc generated in the R phase and the T phase will be described with reference to FIGS. 3 to 5. The R phase Ioc (r) is generated at a position 90 degrees from the R phase, and the T phase Ioc (t) is generated at a position 90 degrees from the T phase. Further, when the magnitude of Ioc (r) and the magnitude of Ioc (t) are equal, Ioc (rt) is generated at the position of 180 degrees by vector synthesis.

また、Ｔ相が地絡した場合には、図４に示すように、Ｉｏｒ（ｔ）とＩｏｃ（ｒｔ）のベクトル合成がＩｏになる。つまり、Ｔ相が地絡した場合には、「Ｉｏ＞Ｉｏｒ（ｔ）」であり、Ｉｏは、θｔの範囲で発生する。 Further, when the T phase has a ground fault, as shown in FIG. 4, the vector synthesis of Ior (t) and Ioc (rt) becomes Io. That is, when the T phase has a ground fault, “Io> Ior (t)”, and Io occurs in the range of θt.

また、Ｒ相が地絡した場合には、図５に示すように、Ｉｏｒ（ｒ）とＩｏｃ（ｒｔ）のベクトル合成がＩｏになる。つまり、Ｒ相が地絡した場合には、「Ｉｏ＜Ｉｏｒ（ｒ）」であり、Ｉｏは、θｒの範囲で発生する。 Further, when the R phase has a ground fault, as shown in FIG. 5, the vector synthesis of Ior (r) and Ioc (rt) becomes Io. That is, when the R phase has a ground fault, “Io <Ior (r)”, and Io occurs in the range of θr.

本願の発明者らは、Ｉｏ、Ｉｏｒ（ｒ）、Ｉｏｒ（ｔ）、Ｉｏｃについて、経験から導き出した妥当な範囲の値を用いて計算することにより、Ｉｏｃが変動する範囲（以下、「変動範囲」という。）を突き止めた。この変動範囲に基づいて、地絡がＲ相で発生しているのか、Ｔ相で発生しているのかを判定することができる。Ｉｏｒ地絡点電流検出ソフト組込型地絡電流抑制システム１では、この結果を利用することにより、Ｒ相とＴ相のどちらに地絡が発生しているのかを特定する。また、Ｉｏｒ（ｒ）またはＩｏｒ（ｔ）が流れる漏電抵抗（Ｒｘ）は、対地静電容量（Ｃｘ）から算出することができる。よって、Ｉｏｒ地絡点電流検出ソフト組込型地絡電流抑制システム１では、まず、Ｃｘを求め、次に、Ｃｘに基づいて、Ｒｘを算出する。 The inventors of the present application calculate the range of Ioc, Ior (r), Ior (t), and Ioc by using the values in a reasonable range derived from experience (hereinafter, "variable range"). ".) Was found. Based on this fluctuation range, it can be determined whether the ground fault occurs in the R phase or the T phase. The Ior ground fault point current detection software built-in ground fault current suppression system 1 uses this result to identify whether the ground fault is occurring in the R phase or the T phase. Further, the leakage resistance (Rx) through which Ior (r) or Ior (t) flows can be calculated from the ground capacitance (Cx). Therefore, in the Ior ground fault point current detection software built-in type ground fault current suppression system 1, Cx is first obtained, and then Rx is calculated based on Cx.

地絡特定部１７は、監視部１６による監視結果に基づいて、地絡が発生している相を特定する。 The ground fault specifying unit 17 identifies the phase in which the ground fault is occurring based on the monitoring result by the monitoring unit 16.

例えば、図６（ａ）に示すように、Ｉｏがθ１の場所に発生した場合において、Ｒ相に地絡が生じていれば、ベクトルの合成により、Ｉｏｃ（ｒｔ）１は、１８０度方向に発生し、Ｔ相に地絡が生じていれば、Ｉｏｃ（ｒｔ）２は、０度方向に発生する。ここで、図３に示すように、Ｉｏｃ（ｒｔ）は、１８０度方向に発生する。よって、地絡特定部１７は、１８０度方向に発生しているＩｏｃ（ｒｔ）１が正解として、Ｒ相に地絡が発生していると特定する。 For example, as shown in FIG. 6 (a), when Io occurs at the location of θ1, if a ground fault occurs in the R phase, the Ioc (rt) 1 is oriented in the 180-degree direction by vector synthesis. If it occurs and a ground fault has occurred in the T phase, Ioc (rt) 2 will occur in the 0 degree direction. Here, as shown in FIG. 3, the Ioc (rt) is generated in the 180-degree direction. Therefore, the ground fault specifying unit 17 specifies that a ground fault has occurred in the R phase, with Ioc (rt) 1 occurring in the 180-degree direction as the correct answer.

また、例えば、図６（ｂ）に示すように、Ｉｏがθ２の場所に発生した場合において、Ｒ相に地絡が生じていれば、Ｉｏｃ（ｒｔ）１は、１８０度方向に発生し、Ｔ相に地絡が生じていれば、Ｉｏｃ（ｒｔ）２は、同様に、１８０度方向に発生する。この場合には、両方とも１８０度方向に発生しているため、上述した手順では、正解を求めることが困難である。 Further, for example, as shown in FIG. 6 (b), when Io occurs at the location of θ2, if a ground fault occurs in the R phase, Ioc (rt) 1 occurs in the 180-degree direction. If a ground fault has occurred in the T phase, Ioc (rt) 2 will similarly occur in the 180 degree direction. In this case, since both occur in the 180-degree direction, it is difficult to obtain the correct answer by the above-mentioned procedure.

絶縁監視装置１３は、１秒間に所定のタイミング（例えば、１秒間に４回）でＩｏやＩｏｃを求めている。絶縁監視装置１３は、Ｉｏｃ（ｒｔ）１とＩｏｃ（ｒｔ）２を経時的に監視し、変化の度合を比較する。ここで、Ｉｏｃは、ほぼ一定であり変化しない性質であることが分かっている。よって、地絡特定部１７は、Ｉｏｃ（ｒｔ）１とＩｏｃ（ｒｔ）２の経時的な変化を監視し、変化の度合が小さい方を正解とする。例えば、Ｉｏｃ（ｒｔ）２の方がＩｏｃ（ｒｔ）１よりも変化が小さければ、地絡特定部１７は、Ｉｏｃ（ｒｔ）２を正解として、Ｔ相に地絡が発生していると特定する。 The insulation monitoring device 13 obtains Io and Ioc at a predetermined timing per second (for example, four times per second). The insulation monitoring device 13 monitors Ioc (rt) 1 and Ioc (rt) 2 over time and compares the degree of change. Here, the Ioc is known to be a property that is almost constant and does not change. Therefore, the ground fault identifying unit 17 monitors the changes over time of Ioc (rt) 1 and Ioc (rt) 2, and the one with the smaller degree of change is the correct answer. For example, if the change in Ioc (rt) 2 is smaller than that in Ioc (rt) 1, the ground fault specifying unit 17 identifies that a ground fault has occurred in the T phase with Ioc (rt) 2 as the correct answer. do.

算出部１４は、地絡特定部１７により特定した地絡が発生している相のＩｏｒを算出する。 The calculation unit 14 calculates the Ior of the phase in which the ground fault specified by the ground fault specifying unit 17 is occurring.

制御部１５は、地絡が発生している相のＩｏｒが所定時間（例えば、６０秒間）継続して第１閾値（例えば、５０ｍＡ）を超えているかどうかを判断し、Ｉｏｒが所定時間継続して第１閾値を超えていると判断した場合、切替スイッチ１１ｂを開放して地絡抑制状態に制御する。 The control unit 15 determines whether or not the Ior of the phase in which the ground fault is occurring continuously exceeds the first threshold value (for example, 50 mA) for a predetermined time (for example, 60 seconds), and the Ior continues for a predetermined time. When it is determined that the first threshold value is exceeded, the changeover switch 11b is opened to control the ground fault suppression state.

算出部１４は、切替スイッチ１１ｂが開放されて地絡抑制状態になった場合、切替スイッチ１１ｂが閉塞されている状態を想定して、想定Ｉｏと、想定Ｉｏｒを算出する。なお、算出部１４では、切替スイッチ１１ｂが閉塞されて、抑制抵抗１１ａに電流が流れていない場合においてＩｏｒなどを算出するときと、切替スイッチ１１ｂが開放されて、抑制抵抗１１ａに電流が流れている場合においてＩｏｒなどを算出するときとでは、異なる関数を用いている。 When the changeover switch 11b is opened and the ground fault is suppressed, the calculation unit 14 calculates the assumed Io and the assumed Ior on the assumption that the changeover switch 11b is closed. In the calculation unit 14, when the changeover switch 11b is closed and the current does not flow through the suppression resistance 11a, Ior or the like is calculated, and when the changeover switch 11b is opened and the current flows through the suppression resistance 11a. In this case, a different function is used when calculating Ior or the like.

制御部１５は、算出部１４により算出した想定Ｉｏｒが所定時間（例えば、６０秒間）継続して第２閾値（例えば、２０ｍＡ）を下まわっているかどうかを判断し、想定Ｉｏｒが所定時間継続して第２閾値を下まわっていると判断した場合、切替スイッチ１１ｂを閉塞して地絡抑制状態を解除する。 The control unit 15 determines whether or not the assumed Ior calculated by the calculation unit 14 continues to be below the second threshold value (for example, 20 mA) for a predetermined time (for example, 60 seconds), and the assumed Ior continues for a predetermined time. If it is determined that the value is below the second threshold value, the changeover switch 11b is closed to release the ground fault suppression state.

よって、本開示のＩｏｒ地絡点電流検出ソフト組込型地絡電流抑制システム１によれば、切替スイッチ１１ｂが閉塞している状態において、Ｉｏｒが所定時間継続して第１閾値を超えていると判断した場合、切替スイッチ１１ｂを開放して地絡抑制状態に制御し、その後、地絡が発生している相を特定し、切替スイッチ１１ｂが閉塞されている状態を想定して、想定Ｉｏｒが所定時間継続して第２閾値を下まわっていると判断した場合、切替スイッチ１１ｂを閉塞して地絡抑制状態を解除するので、Ｉｏｒが所定時間継続して第１閾値を超えた場合に、切替スイッチ１１ｂを開放して抑制抵抗１１ａによりＢ種接地線を流れる電流を抑制し、その後、想定Ｉｏｒが所定時間継続して第２閾値を下まわった場合に、切替スイッチ１１ｂを閉塞して通常状態に素早く戻すことができる。 Therefore, according to the Ior ground fault current detection software built-in type ground fault current suppression system 1 of the present disclosure, the Ior continuously exceeds the first threshold value for a predetermined time while the changeover switch 11b is closed. If it is determined that, the changeover switch 11b is opened to control the ground fault suppression state, then the phase in which the ground fault is occurring is specified, and assuming the changeover switch 11b is blocked, the assumed Ior When it is determined that the current is continuously below the second threshold value for a predetermined time, the changeover switch 11b is closed to release the ground fault suppression state. Therefore, when the Ior continuously exceeds the first threshold value for a predetermined time. , The changeover switch 11b is opened to suppress the current flowing through the class B ground wire by the suppression resistor 11a, and then, when the assumed Ior continues to fall below the second threshold value for a predetermined time, the changeover switch 11b is closed. You can quickly return to the normal state.

よって、本開示のＩｏｒ地絡点電流検出ソフト組込型地絡電流抑制システム１は、絶縁監視用の信号として商用周波数とは異なる特定周波数を注入する構成ではないため、ＶＶＶＦインバータ制御により発生する周波数や電路の対地静電容量が増加することにより発生する低次高調波に影響されずにＩｏｒを検出することができる。 Therefore, the Ior ground fault point current detection software built-in type ground fault current suppression system 1 of the present disclosure is not configured to inject a specific frequency different from the commercial frequency as a signal for insulation monitoring, and thus is generated by VVVF inverter control. Ior can be detected without being affected by the low-order harmonics generated by the increase in frequency and the capacitance to ground of the electric circuit.

また、Ｉｏｒ地絡点電流検出ソフト組込型地絡電流抑制システム１では、想定Ｉｏｒが所定時間継続して第２閾値を下まわっていると判断した場合、切替スイッチ１１ｂを閉塞して地絡抑制状態を解除して、通常状態に戻すため、保守管理を行っている業者に対してアラームが通知され続けることがなく、無駄な出動を低減させることができ、効率的な保守管理を行うことができる。 Further, in the Ior ground fault point current detection software built-in type ground fault current suppression system 1, when it is determined that the assumed Ior is continuously below the second threshold value for a predetermined time, the changeover switch 11b is closed and the ground fault. Since the suppression state is released and the normal state is restored, the alarm does not continue to be notified to the contractor who is performing maintenance management, unnecessary dispatch can be reduced, and efficient maintenance management should be performed. Can be done.

さらに、Ｉｏｒ地絡点電流検出ソフト組込型地絡電流抑制システム１では、非接地相のどちらにＩｏｒが発生しているかを特定することができるので、地絡が発生している相を重点的に検査することができ、効率的な検査を行うことができる。 Furthermore, in the Ior ground fault point current detection software built-in type ground fault current suppression system 1, it is possible to specify which of the non-grounded phases the Ior is occurring in, so the phase in which the ground fault is occurring is emphasized. It is possible to carry out an efficient inspection.

＜地絡が発生していない場合における制御方法について＞
ここで、地絡が発生していない場合におけるＩｏｒ地絡点電流検出ソフト組込型地絡電流抑制システム１の動作について、図７に示すフローチャートを用いて説明する。なお、切替スイッチ１１ｂは、図１に示すように、閉塞状態になっている。 <Control method when no ground fault has occurred>
Here, the operation of the Ior ground fault point current detection software built-in type ground fault current suppression system 1 when no ground fault has occurred will be described with reference to the flowchart shown in FIG. 7. As shown in FIG. 1, the changeover switch 11b is in a closed state.

ステップＳ１において、絶縁監視装置１３は、漏洩電流検出部１２により検出したＩｏと、Ｒ相－Ｔ相間に印加されている電圧（基準電圧）Ｖに基づいて、位相角度（θ）を算出する。 In step S1, the insulation monitoring device 13 calculates the phase angle (θ) based on the Io detected by the leakage current detection unit 12 and the voltage (reference voltage) V applied between the R phase and the T phase.

ステップＳ２において、絶縁監視装置１３は、Ｉｏと位相角度（θ）に基づいて、Ｉｏｒを算出する。例えば、絶縁監視装置１３は、（１）式にＩｏと位相角度（θ）を代入して、Ｉｏｒを算出する。
Ｉｏｒ＝Ｉｏ×ｓｉｎθ／ｃｏｓ（π／６） ・・・（１） In step S2, the insulation monitoring device 13 calculates Ior based on Io and the phase angle (θ). For example, the insulation monitoring device 13 substitutes Io and the phase angle (θ) into the equation (1) to calculate the Ior.
Ior = Io × sinθ / cos (π / 6) ・ ・ ・ (1)

ステップＳ３において、絶縁監視装置１３は、Ｉｏと位相角度（θ）に基づいて、Ｉｏｃを算出する。 In step S3, the insulation monitoring device 13 calculates Ioc based on Io and the phase angle (θ).

また、絶縁監視装置１３は、切替スイッチ１１ｂが閉塞されている状態（通常状態）におけるＩｏと位相角度（θ）とに基づいて、配線浮遊容量（Ｃｘ）を算出する。図８に解放時の等価回路を示す。漏電が生じていない場合には、図８に示すように、Ｃｘのみが変数となるので、計算によってＣｘを求めることができる。なお、配線浮遊容量は、対地静電容量ともいい、Ｃｘは、「Ｃｘ＝Ｃｒ」または「Ｃｘ＝Ｃｔ」である。さらに、絶縁監視装置１３は、通常状態におけるＩｏｒに基づいて、漏電抵抗（Ｒｘ）を算出する。なお、Ｒｘは、「Ｒｘ＝Ｒｒ」または「Ｒｘ＝Ｒｔ」である。 Further, the insulation monitoring device 13 calculates the wiring stray capacitance (Cx) based on the Io and the phase angle (θ) in the state where the changeover switch 11b is closed (normal state). FIG. 8 shows an equivalent circuit at the time of release. When no electric leakage has occurred, as shown in FIG. 8, since only Cx is a variable, Cx can be obtained by calculation. The wiring stray capacitance is also referred to as ground capacitance, and Cx is "Cx = Cr" or "Cx = Ct". Further, the insulation monitoring device 13 calculates the leakage resistance (Rx) based on the Ior in the normal state. In addition, Rx is "Rx = Rr" or "Rx = Rt".

＜地絡が発生している場合における制御方法について＞
つぎに、地絡が発生している場合におけるＩｏｒ地絡点電流検出ソフト組込型地絡電流抑制システム１の動作について、図９に示すフローチャートを用いて説明する。 <Control method when a ground fault has occurred>
Next, the operation of the Ior ground fault point current detection software built-in type ground fault current suppression system 1 when a ground fault has occurred will be described with reference to the flowchart shown in FIG.

ステップＳ１１において、絶縁監視装置１３は、正常時のＩｏに基づいてＣｘを求める。正常時とは、切替スイッチ１１ｂが閉塞されている状態（通常状態）をいう。 In step S11, the insulation monitoring device 13 obtains Cx based on the normal Io. The normal state means a state in which the changeover switch 11b is closed (normal state).

ステップＳ１２において、絶縁監視装置１３は、ステップＳ２の工程で算出したＩｏｒが所定時間（例えば、６０秒間）継続して第１閾値（５０ｍＡ）を超えているかどうかを判断する。所定時間継続して第１閾値を超えている場合（Ｙｅｓ）には、ステップＳ１３に進み、所定時間継続して第１閾値を超えていない場合（Ｎｏ）には、ステップＳ１１の工程に戻る。 In step S12, the insulation monitoring device 13 determines whether or not the Ior calculated in the step S2 continuously exceeds the first threshold value (50 mA) for a predetermined time (for example, 60 seconds). If the first threshold value is continuously exceeded for a predetermined time (Yes), the process proceeds to step S13, and if the first threshold value is not continuously exceeded for a predetermined time (No), the process returns to the step S11.

ステップＳ１３において、絶縁監視装置１３は、切替スイッチ１１ｂを開放状態にする。切替スイッチ１１ｂが開放状態になると、図１０に示すように、Ｂ種接地線を流れる電流は、抑制抵抗１１ａにより抑制される。また、切替スイッチ１１ｂが開放状態になり、抑制抵抗１１ａが挿入されると、図１０に示すように、Ｓ相にも配線浮遊容量（Ｃｓ）が発生する。なお、「Ｃｘ＝Ｃｓ」である。 In step S13, the insulation monitoring device 13 opens the changeover switch 11b. When the changeover switch 11b is in the open state, as shown in FIG. 10, the current flowing through the class B ground wire is suppressed by the suppression resistance 11a. Further, when the changeover switch 11b is opened and the suppression resistance 11a is inserted, a stray stray capacitance (Cs) is generated in the S phase as shown in FIG. In addition, "Cx = Cs".

ステップＳ１４において、絶縁監視装置１３は、Ｉｏｃの変化量に基づいて、地絡している相を特定する。具体的には、Ｒｒに流れるＩｏｒ（ｒ）と、Ｒｔに流れるＩｏｒ（ｔ）をＣｘにより算出し、Ｒ相地絡かＴ相地絡かを特定する。 In step S14, the insulation monitoring device 13 identifies the phase in which the ground fault is occurring based on the amount of change in Ioc. Specifically, the Ior (r) flowing through Rr and the Ior (t) flowing through Rt are calculated by Cx, and whether it is an R-phase ground fault or a T-phase ground fault is specified.

ステップＳ１５において、絶縁監視装置１３は、地絡している相について、切替スイッチ１１ｂが閉塞されている状態を想定して、想定Ｉｏと、想定Ｉｏｒ、想定Ｉｏｃを算出する。なお、想定Ｉｏｒとは、Ｉｏｒ（ｒ）またはＩｏｒ（ｔ）である。また、想定Ｉｏｒは、Ｉｏ、Ｃｘ、Ｒｘ、Ｒ相－Ｔ相間の基準電圧、基準周波数（Ｆ）から算出されるが、地絡している相により用いる関数は異なる。 In step S15, the insulation monitoring device 13 calculates the assumed Io, the assumed Ior, and the assumed Ioc for the phase in which the ground fault occurs, assuming that the changeover switch 11b is blocked. The assumed Ior is Ior (r) or Ior (t). Further, the assumed Ior is calculated from Io, Cx, Rx, the reference voltage between the R phase and the T phase, and the reference frequency (F), but the function used differs depending on the phase having a ground fault.

ステップＳ１６において、絶縁監視装置１３は、想定Ｉｏｒが所定時間（例えば、６０秒間）継続して第２閾値（例えば、２０ｍＡ）を下まわっているかどうかを判断する。想定Ｉｏｒが所定時間継続して第２閾値を下まわっていると判断した場合（Ｙｅｓ）には、ステップＳ１７に進む。想定Ｉｏｒが所定時間継続して第２閾値を下まわっていないと判断した場合（Ｎｏ）には、ステップＳ１５の工程に戻る。 In step S16, the insulation monitoring device 13 determines whether or not the assumed Ior is continuously below the second threshold value (for example, 20 mA) for a predetermined time (for example, 60 seconds). If it is determined that the assumed Ior is continuously below the second threshold value for a predetermined time (Yes), the process proceeds to step S17. If it is determined that the assumed Ior has not continuously fallen below the second threshold value for a predetermined time (No), the process returns to the step S15.

ステップＳ１７において、絶縁監視装置１３は、切替スイッチ１１ｂを閉塞して地絡抑制状態を解除する。 In step S17, the insulation monitoring device 13 closes the changeover switch 11b to release the ground fault suppression state.

＜第２実施形態＞
つぎに、第２実施形態について説明する。なお、第１実施形態と同一の構成要素については、同じ符号を付し、詳細な説明を省略する。 <Second Embodiment>
Next, the second embodiment will be described. The same components as those in the first embodiment are designated by the same reference numerals, and detailed description thereof will be omitted.

Ｉｏｒ地絡点電流検出ソフト組込型地絡電流抑制システム２は、Ｉｏｒ地絡点の電流を検出するソフトにより地絡電流を抑制する機能を有しており、図１１に示すように、変圧器２０と、地絡電流抑制部１１と、漏洩電流検出部１２と、絶縁監視装置２１とを備える。図１１には、変圧器２０の二次側が示されている。第２実施形態においては、変圧器２０の二次側は、Ｒ相、Ｎ相、Ｔ相の単相３線結線であり、該単相３線結線の２つの端部に接続される各電線を活線とし、中間点に接続される電線をＢ種接地線である場合を例示して説明する。 The Ior ground fault current detection software embedded type ground fault current suppression system 2 has a function of suppressing the ground fault current by the software that detects the current of the Ior ground fault point, and is transformed as shown in FIG. A device 20, a ground fault current suppressing unit 11, a leakage current detecting unit 12, and an insulation monitoring device 21 are provided. FIG. 11 shows the secondary side of the transformer 20. In the second embodiment, the secondary side of the transformer 20 is an R-phase, N-phase, and T-phase single-phase three-wire connection, and each electric wire connected to two ends of the single-phase three-wire connection. Will be described as an example in the case where the electric wire connected to the intermediate point is a class B ground wire.

＜地絡が発生していない場合における制御方法について＞
ここで、地絡が発生していない場合におけるＩｏｒ地絡点電流検出ソフト組込型地絡電流抑制システム２の動作について、図１２に示すフローチャートを用いて説明する。なお、切替スイッチ１１ｂは、図１１に示すように、閉塞状態になっている。 <Control method when no ground fault has occurred>
Here, the operation of the Ior ground fault point current detection software built-in type ground fault current suppression system 2 when no ground fault has occurred will be described with reference to the flowchart shown in FIG. As shown in FIG. 11, the changeover switch 11b is in a closed state.

ステップＳ２１において、絶縁監視装置２１は、漏洩電流検出部１２により検出したＩｏと、Ｒ相－Ｔ相間に印加されている電圧（基準電圧）Ｖに基づいて、位相角度（θ）を算出する。 In step S21, the insulation monitoring device 21 calculates the phase angle (θ) based on the Io detected by the leakage current detection unit 12 and the voltage (reference voltage) V applied between the R phase and the T phase.

ステップＳ２２において、絶縁監視装置２１は、Ｉｏと位相角度（θ）に基づいて、Ｉｏｒを算出する。例えば、絶縁監視装置２１は、（２）式にＩｏと位相角度（θ）を代入して、Ｉｏｒを算出する。
Ｉｏｒ＝Ｉｏ×ｃｏｓθ ・・・（２） In step S22, the insulation monitoring device 21 calculates Ior based on Io and the phase angle (θ). For example, the insulation monitoring device 21 calculates Ior by substituting Io and the phase angle (θ) into Eq. (2).
Ior = Io × cosθ ・ ・ ・ (2)

ステップＳ２３において、絶縁監視装置２１は、Ｉｏと位相角度（θ）に基づいて、Ｉｏｃを算出する。 In step S23, the insulation monitoring device 21 calculates Ioc based on Io and the phase angle (θ).

Ｃｘは、「Ｃｘ＝Ｃｒ」または「Ｃｘ＝Ｃｔ」である。さらに、絶縁監視装置１３は、通常状態におけるＩｏｒに基づいて、漏電抵抗（Ｒｘ）を算出する。詳細には、絶縁監視装置１３は、Ｒｘを求めた後に切替スイッチ１１ｂが開放状態したときに一旦求めたＲｘをＲｘ１としてＣｘを求めている。図１３に解法時の等価回路を示す。つまり、絶縁監視装置２１（算出部）は、地絡直後のＲｘ１に基づいて、未知数であるＣｘを求める。なお、図１３では、Ｒ相に地絡が生じた場合を示しており、Ｒｘ１は、「Ｒｘ１＝Ｒｒ」である。また、Ｔ相に地絡が生じた場合には、「Ｒｘ１＝Ｒｔ」である。 Cx is "Cx = Cr" or "Cx = Ct". Further, the insulation monitoring device 13 calculates the leakage resistance (Rx) based on the Ior in the normal state. Specifically, the insulation monitoring device 13 obtains Cx with Rx once obtained when the changeover switch 11b is opened after obtaining Rx as Rx1. FIG. 13 shows an equivalent circuit at the time of solving. That is, the insulation monitoring device 21 (calculation unit) obtains an unknown number of Cx based on Rx1 immediately after the ground fault. Note that FIG. 13 shows a case where a ground fault occurs in the R phase, and Rx1 is “Rx1 = Rr”. Further, when a ground fault occurs in the T phase, “Rx1 = Rt”.

＜地絡が発生している場合における制御方法について＞
地絡が発生している場合におけるＩｏｒ地絡点電流検出ソフト組込型地絡電流抑制システム２の動作について、図１４に示すフローチャートを用いて説明する。 <Control method when a ground fault has occurred>
The operation of the Ior ground fault point current detection software built-in type ground fault current suppression system 2 when a ground fault has occurred will be described with reference to the flowchart shown in FIG.

ステップＳ３１において、絶縁監視装置２１は、ステップＳ２２の工程で算出したＩｏｒが所定時間（例えば、６０秒間）継続して第１閾値（５０ｍＡ）を超えているかどうかを判断する。所定時間継続して第１閾値を超えている場合（Ｙｅｓ）には、ステップＳ３２に進み、所定時間継続して第１閾値を超えていない場合（Ｎｏ）には、ステップＳ３１の工程を繰り返す。 In step S31, the insulation monitoring device 21 determines whether or not the Ior calculated in the step S22 continuously exceeds the first threshold value (50 mA) for a predetermined time (for example, 60 seconds). If the first threshold value is continuously exceeded for a predetermined time (Yes), the process proceeds to step S32, and if the first threshold value is not continuously exceeded for a predetermined time (No), the process of step S31 is repeated.

ステップＳ３２において、絶縁監視装置２１は、切替スイッチ１１ｂを開放状態にする。切替スイッチ１１ｂが開放状態になると、図１５に示すように、Ｂ種接地線を流れる電流が抑制抵抗１１ａに流れるようになる。また、切替スイッチ１１ｂが開放状態になり、抑制抵抗１１ａが挿入されると、図１５に示すように、Ｎ相にも配線浮遊容量（Ｃｎ）が発生する。なお、「Ｃｘ＝Ｃｎ」である。 In step S32, the insulation monitoring device 21 opens the changeover switch 11b. When the changeover switch 11b is in the open state, as shown in FIG. 15, the current flowing through the class B ground wire flows to the suppression resistance 11a. Further, when the changeover switch 11b is opened and the suppression resistance 11a is inserted, a stray stray capacitance (Cn) is also generated in the N phase as shown in FIG. It should be noted that "Cx = Cn".

ステップＳ３３において、絶縁監視装置２１は、Ｉｏｃの変化量に基づいて、地絡している相を特定する。具体的には、Ｒｒに流れるＩｏｒ（ｒ）と、Ｒｔに流れるＩｏｒ（ｔ）を算出し、Ｒ相地絡かＴ相地絡かを特定する。 In step S33, the insulation monitoring device 21 identifies the phase in which the ground fault is occurring based on the amount of change in Ioc. Specifically, the Ior (r) flowing through Rr and the Ior (t) flowing through Rt are calculated, and whether it is an R-phase ground fault or a T-phase ground fault is specified.

ステップＳ３４において、絶縁監視装置２１は、所定の演算によりＲｘ１を算出する。例えば、Ｒ相に地絡が発生している場合には、「Ｖｒ／Ｉｏｒ」によりＲｘ１を算出し、Ｔ相に地絡が発生している場合には、「Ｖｔ／Ｉｏｒ」によりＲｘ１を算出する。 In step S34, the insulation monitoring device 21 calculates Rx1 by a predetermined calculation. For example, when a ground fault occurs in the R phase, Rx1 is calculated by "Vr / Ior", and when a ground fault occurs in the T phase, Rx1 is calculated by "Vt / Ior". do.

ステップＳ３５において、絶縁監視装置２１は、ステップＳ３４の工程により算出したＲｘ１に基づいて、Ｃｘを算出する。上述したように、図１３は、Ｃｘを算出するための等価回路である。図１３では、Ｒ相に地絡が発生した場合を示している。また、図１３では、「Ｃｘ＝Ｃｎ＝Ｃｒ＝Ｃｔ」である。 In step S35, the insulation monitoring device 21 calculates Cx based on Rx1 calculated in the step S34. As described above, FIG. 13 is an equivalent circuit for calculating Cx. FIG. 13 shows a case where a ground fault occurs in the R phase. Further, in FIG. 13, “Cx = Cn = Cr = Ct”.

ステップＳ３６において、絶縁監視装置２１は、地絡している相について、切替スイッチ１１ｂが閉塞されている状態を想定して、ステップＳ３５により算出したＣｘに基づいて、想定Ｉｏと、想定Ｉｏｒ、想定Ｉｏｃを算出する。本工程では、ステップＳ３５の工程によりＣｘが算出されている前提でＲｘを再計算している。これは、時間の経過によりＲｘが変化するので、変化後のＲｘをＲｘ２として想定Ｉｏｒを算出している。図１６に解法時の等価回路を示す。未知数であるＲｘ２は、既知であるＣｘに基づいて算出することができる。なお、想定Ｉｏｒとは、Ｉｏｒ（ｒ）またはＩｏｒ（ｔ）である。また、想定Ｉｏｒは、Ｉｏ、Ｃｘ、Ｒｘ、Ｒ相－Ｔ相間の基準電圧、基準周波数（Ｆ）から算出されるが、地絡している相により用いる関数は異なる。 In step S36, the insulation monitoring device 21 assumes a state in which the changeover switch 11b is blocked for the phase having a ground fault, and based on the Cx calculated in step S35, the assumed Io, the assumed Ior, and the assumed Ior. Calculate Ioc. In this step, Rx is recalculated on the premise that Cx is calculated by the step S35. This is because Rx changes with the passage of time, so the assumed Ior is calculated with the changed Rx as Rx2. FIG. 16 shows an equivalent circuit at the time of solving. Rx2, which is an unknown number, can be calculated based on known Cx. The assumed Ior is Ior (r) or Ior (t). Further, the assumed Ior is calculated from Io, Cx, Rx, the reference voltage between the R phase and the T phase, and the reference frequency (F), but the function used differs depending on the phase having a ground fault.

ステップＳ３７において、絶縁監視装置２１は、想定Ｉｏｒが所定時間（例えば、６０秒間）継続して第２閾値（例えば、２０ｍＡ）を下まわっているかどうかを判断する。想定Ｉｏｒが所定時間継続して第２閾値を下まわっていると判断した場合（Ｙｅｓ）には、ステップＳ３８に進む。想定Ｉｏｒが所定時間継続して第２閾値を下まわっていないと判断した場合（Ｎｏ）には、ステップＳ３６の工程に戻る。 In step S37, the insulation monitoring device 21 determines whether or not the assumed Ior is continuously below the second threshold value (for example, 20 mA) for a predetermined time (for example, 60 seconds). If it is determined that the assumed Ior is continuously below the second threshold value for a predetermined time (Yes), the process proceeds to step S38. If it is determined that the assumed Ior has not continuously fallen below the second threshold value for a predetermined time (No), the process returns to the step S36.

ステップＳ３８において、絶縁監視装置２１は、切替スイッチ１１ｂを閉塞して地絡抑制状態を解除する。 In step S38, the insulation monitoring device 21 closes the changeover switch 11b to release the ground fault suppression state.

よって、本開示のＩｏｒ地絡点電流検出ソフト組込型地絡電流抑制システム２によれば、切替スイッチ１１ｂが閉塞している状態において、Ｉｏｒが所定時間継続して第１閾値を超えていると判断した場合、切替スイッチ１１ｂを開放して地絡抑制状態に制御し、その後、切替スイッチ１１ｂが閉塞されている状態を想定して、想定Ｉｏｒが所定時間継続して第２閾値を下まわっていると判断した場合、切替スイッチ１１ｂを閉塞して地絡抑制状態を解除するので、Ｉｏｒが所定時間継続して第１閾値を超えた場合に、切替スイッチ１１ｂを開放して抑制抵抗１１ａによりＢ種接地線を流れる電流を抑制し、その後、想定Ｉｏｒが所定時間継続して第２閾値を下まわった場合に、切替スイッチ１１ｂを閉塞して通常状態に素早く戻すことができる。 Therefore, according to the Ior ground fault current detection software built-in type ground fault current suppression system 2 of the present disclosure, the Ior continuously exceeds the first threshold value for a predetermined time while the changeover switch 11b is closed. If it is determined that, the changeover switch 11b is opened to control the ground fault suppression state, and then, assuming that the changeover switch 11b is blocked, the assumed Ior continues to fall below the second threshold value for a predetermined time. If it is determined that the changeover switch 11b is closed, the ground fault suppression state is released. Therefore, when the Ior continuously exceeds the first threshold value for a predetermined time, the changeover switch 11b is opened and the suppression resistance 11a is used. When the current flowing through the class B ground wire is suppressed and then the assumed Ior continues to fall below the second threshold value for a predetermined time, the changeover switch 11b can be closed to quickly return to the normal state.

よって、本開示のＩｏｒ地絡点電流検出ソフト組込型地絡電流抑制システム２は、絶縁監視用の信号として商用周波数とは異なる特定周波数を注入する構成ではないため、ＶＶＶＦインバータ制御により発生する周波数や電路の対地静電容量が増加することにより発生する低次高調波に影響されずにＩｏｒを検出することができる。 Therefore, the Ior ground fault point current detection software built-in type ground fault current suppression system 2 of the present disclosure is not configured to inject a specific frequency different from the commercial frequency as a signal for insulation monitoring, and thus is generated by VVVF inverter control. Ior can be detected without being affected by the low-order harmonics generated by the increase in frequency and the capacitance to ground of the electric circuit.

また、Ｉｏｒ地絡点電流検出ソフト組込型地絡電流抑制システム２では、想定Ｉｏｒが所定時間継続して第２閾値を下まわっていると判断した場合、切替スイッチ１１ｂを閉塞して地絡抑制状態を解除して、通常状態に戻すため、保守管理を行っている業者に対してアラームが通知され続けることがなく、無駄な出動を低減させることができ、効率的な保守管理を行うことができる。 Further, in the Ior ground fault point current detection software built-in type ground fault current suppression system 2, when it is determined that the assumed Ior is continuously below the second threshold value for a predetermined time, the changeover switch 11b is closed and the ground fault. Since the suppression state is released and the normal state is restored, the alarm does not continue to be notified to the contractor who is performing maintenance management, unnecessary dispatch can be reduced, and efficient maintenance management should be performed. Can be done.

さらに、Ｉｏｒ地絡点電流検出ソフト組込型地絡電流抑制システム２では、非接地相のどちらにＩｏｒが発生しているかを特定することができるので、地絡が発生している相を重点的に検査することができ、効率的な検査を行うことができる。 Furthermore, in the Ior ground fault point current detection software built-in type ground fault current suppression system 2, it is possible to specify which of the non-grounded phases the Ior is occurring in, so the phase in which the ground fault is occurring is emphasized. It is possible to carry out an efficient inspection.

＜他の実施形態＞
また、Ｉｏｒ地絡点電流検出ソフト組込型地絡電流抑制システム１，２は、Ｉｏｒが所定時間継続して第１閾値を超えていると判断し、切替スイッチ１１ｂを開放して地絡抑制状態に制御し、その後、想定Ｉｏｒが所定時間継続して第２閾値を下まわっていると判断し、切替スイッチ１１ｂを閉塞して地絡抑制状態を解除したことを記録部に記録する構成でもよい。 <Other embodiments>
Further, the Ior ground fault point current detection software built-in type ground fault current suppression systems 1 and 2 determine that the Ior continuously exceeds the first threshold value for a predetermined time, and open the changeover switch 11b to suppress the ground fault. Even in a configuration in which the state is controlled, and then it is determined that the assumed Ior has been continuously below the second threshold value for a predetermined time, and the changeover switch 11b is closed to release the ground fault suppression state in the recording unit. good.

当該構成によれば、特に営業時間外の深夜や休日などにおいて、Ｉｏｒが所定時間継続して第１閾値を超え、その後、想定Ｉｏｒが所定時間継続して第２閾値を下まわったことが記録された場合には、翌日の営業時間などにおいて、担当者が電線路や負荷などの調査に役立てることができる。 According to this configuration, it is recorded that the Ior continuously exceeds the first threshold value for a predetermined time and then the assumed Ior continues to fall below the second threshold value for a predetermined time, especially at midnight or holidays outside business hours. If so, the person in charge can use it to investigate the electric line and load during the business hours of the next day.

１，２ Ｉｏｒ地絡点電流検出ソフト組込型地絡電流抑制システム、１０，２０ 変圧器、１１ 地絡電流抑制部、１１ａ 抑制抵抗、１１ｂ 切替スイッチ、１１ｃ 保護回路、１２ 漏洩電流検出部、１３，２１ 絶縁監視装置、１４ 算出部、１５ 制御部、１６ 監視部、１７ 地絡特定部 1,2 Ior ground fault current detection software built-in ground fault current suppression system, 10,20 transformer, 11 ground fault current suppression unit, 11a suppression resistance, 11b changeover switch, 11c protection circuit, 12 leakage current detection unit, 13,21 Insulation monitoring device, 14 Calculation unit, 15 Control unit, 16 Monitoring unit, 17 Ground fault identification unit

Claims (8)

変圧器のＢ種接地線に設けられ、抑制抵抗と、当該抑制抵抗の両端を開放または閉塞を切り替える切替スイッチとが並列接続されて構成される地絡電流抑制部と、
前記Ｂ種接地線に流れる漏洩電流を検出する漏洩電流検出部と、
前記漏洩電流検出部で検出した漏洩電流に基づいて、対地絶縁抵抗に起因する漏洩電流を算出する算出部と、
前記算出部により算出した対地絶縁抵抗に起因する漏洩電流が所定時間継続して第１閾値を超えているかどうかを判断し、対地絶縁抵抗に起因する漏洩電流が所定時間継続して第１閾値を超えていると判断した場合、前記切替スイッチを開放して地絡抑制状態に制御する制御部とを備え、
前記算出部は、前記切替スイッチが開放されて地絡抑制状態になった場合、前記切替スイッチが閉塞されている状態を想定して、想定漏洩電流と、対地絶縁抵抗に起因する想定漏洩電流を算出し、
前記制御部は、前記算出部により算出した対地絶縁抵抗に起因する想定漏洩電流が所定時間継続して第２閾値を下まわっているかどうかを判断し、対地絶縁抵抗に起因する想定漏洩電流が所定時間継続して第２閾値を下まわっていると判断した場合、前記切替スイッチを閉塞して地絡抑制状態を解除するＩｏｒ地絡点電流検出ソフト組込型地絡電流抑制システム。 A ground fault current suppression unit provided on the B-class grounding wire of a transformer and configured by connecting a suppression resistance and a changeover switch that switches between opening and closing both ends of the suppression resistance in parallel.
A leakage current detection unit that detects the leakage current flowing through the Class B ground wire, and
A calculation unit that calculates the leakage current due to the insulation resistance to the ground based on the leakage current detected by the leakage current detection unit.
It is determined whether or not the leakage current due to the ground insulation resistance calculated by the calculation unit continuously exceeds the first threshold value for a predetermined time, and the leakage current due to the ground insulation resistance continues for a predetermined time to set the first threshold value. If it is determined that the value has been exceeded, a control unit that opens the changeover switch to control the ground fault suppression state is provided.
When the changeover switch is opened and the ground fault is suppressed, the calculation unit calculates the assumed leakage current and the assumed leakage current due to the insulation resistance to the ground, assuming that the changeover switch is closed. Calculate and
The control unit determines whether or not the assumed leakage current due to the ground insulation resistance calculated by the calculation unit continues to fall below the second threshold value for a predetermined time, and the assumed leakage current due to the ground insulation resistance is predetermined. Ior ground fault point current detection software built-in type ground fault current suppression system that closes the changeover switch and releases the ground fault suppression state when it is determined that the value is continuously below the second threshold value for a long time. 前記切替スイッチが閉塞している状態において、接地相以外の相における対地静電容量に起因する漏洩電流の変化を監視する監視部と、
前記監視部による監視結果に基づいて、接地相以外の相のいずれに地絡が発生しているのかを特定する地絡特定部とを備え、
前記算出部は、前記地絡特定部により特定した地絡が発生している相の対地絶縁抵抗に起因する漏洩電流を算出し、
前記制御部は、地絡が発生している相の対地絶縁抵抗に起因する漏洩電流が所定時間継続して第１閾値を超えているかどうかを判断する請求項１記載のＩｏｒ地絡点電流検出ソフト組込型地絡電流抑制システム。 A monitoring unit that monitors changes in leakage current due to capacitance to ground in phases other than the ground phase when the changeover switch is closed.
Based on the monitoring result by the monitoring unit, the ground fault specifying unit is provided to specify which of the phases other than the grounding phase the ground fault is occurring.
The calculation unit calculates the leakage current due to the ground insulation resistance of the phase in which the ground fault specified by the ground fault identification unit is occurring.
The Ior ground fault point current detection according to claim 1, wherein the control unit determines whether or not the leakage current due to the ground insulation resistance of the phase in which the ground fault is occurring continuously exceeds the first threshold value for a predetermined time. Soft embedded ground fault current suppression system. 前記変圧器の二次側は、Ｒ相、Ｓ相、Ｔ相の３相デルタ結線であり、このうち１つの相に接続される電線を前記Ｂ種接地線とし、他の２つの相に接続される電線を活線とする請求項１または２に記載のＩｏｒ地絡点電流検出ソフト組込型地絡電流抑制システム。 The secondary side of the transformer is a three-phase delta connection of R phase, S phase, and T phase, and the electric wire connected to one of them is the B-class ground wire and is connected to the other two phases. The Ior ground fault current detection software built-in type ground fault current suppression system according to claim 1 or 2, wherein the electric wire to be used is a live wire. 前記算出部は、前記切替スイッチが閉塞している状態において対地静電容量を算出する請求項３記載のＩｏｒ地絡点電流検出ソフト組込型地絡電流抑制システム。 The Ior ground fault point current detection software built-in type ground fault current suppression system according to claim 3, wherein the calculation unit calculates the ground capacitance in a state where the changeover switch is closed. 前記算出部は、前記切替スイッチが開放され、地絡抑制状態になった場合に、前記対地静電容量に基づいて対地絶縁抵抗を算出する請求項４記載のＩｏｒ地絡点電流検出ソフト組込型地絡電流抑制システム。 The Ior ground fault point current detection software according to claim 4, wherein the calculation unit calculates the ground insulation resistance based on the ground capacitance when the changeover switch is opened and the ground fault is suppressed. Mold ground fault current suppression system. 前記変圧器の二次側は、単相３線結線であり、該単相３線結線の２つの端部に接続される各電線を活線とし、中間点に接続される電線を前記Ｂ種接地線とする請求項１または２に記載のＩｏｒ地絡点電流検出ソフト組込型地絡電流抑制システム。 The secondary side of the transformer is a single-phase three-wire connection, each electric wire connected to the two ends of the single-phase three-wire connection is a live wire, and the electric wire connected to the intermediate point is the type B. The Ior ground fault current detection software built-in type ground fault current suppression system according to claim 1 or 2, wherein the ground wire is used. 前記算出部は、前記切替スイッチが開放され、地絡抑制状態になった場合に、前記切替スイッチが開放された直後の対地静電容量を算出する請求項６記載のＩｏｒ地絡点電流検出ソフト組込型地絡電流抑制システム。 The Ior ground fault point current detection software according to claim 6, wherein the calculation unit calculates the ground capacitance immediately after the changeover switch is opened when the changeover switch is opened and the ground fault is suppressed. Embedded ground fault current suppression system. 前記算出部は、前記対地静電容量に基づいて対地絶縁抵抗を算出する請求項７記載のＩｏｒ地絡点電流検出ソフト組込型地絡電流抑制システム。 The Ior ground fault point current detection software built-in type ground fault current suppression system according to claim 7, wherein the calculation unit calculates the ground insulation resistance based on the ground capacitance.
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