WO2024079922A1 - Dc insulation resistance monitoring system - Google Patents

Dc insulation resistance monitoring system Download PDF

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Publication number
WO2024079922A1
WO2024079922A1 PCT/JP2023/007584 JP2023007584W WO2024079922A1 WO 2024079922 A1 WO2024079922 A1 WO 2024079922A1 JP 2023007584 W JP2023007584 W JP 2023007584W WO 2024079922 A1 WO2024079922 A1 WO 2024079922A1
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Prior art keywords
voltage
insulation resistance
monitoring system
switch
insulating capacitor
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PCT/JP2023/007584
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French (fr)
Japanese (ja)
Inventor
隆 佐藤
伸一 石崎
深大 佐藤
能康 渡辺
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株式会社日立産機システム
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Publication of WO2024079922A1 publication Critical patent/WO2024079922A1/en

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R27/00—Arrangements for measuring resistance, reactance, impedance, or electric characteristics derived therefrom
    • G01R27/02—Measuring real or complex resistance, reactance, impedance, or other two-pole characteristics derived therefrom, e.g. time constant
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
    • G01R31/50—Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections
    • G01R31/52—Testing for short-circuits, leakage current or ground faults
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection

Definitions

  • the present invention relates to a DC insulation resistance monitoring system.
  • the conventional method for measuring the DC insulation resistance of a power distribution system was to shut down the power distribution system, connect a high-voltage DC power supply, and measure the leakage current. To improve on this, for example, there is a DC insulation resistance monitoring system described in Patent Document 1.
  • the primary neutral point of a grounded instrument transformer connected to a power distribution system is DC insulated by a capacitor, a DC power source is connected to the neutral point, and the leakage current is measured to measure the DC insulation resistance of the power distribution system in a live state.
  • the DC insulation resistance monitoring system described in Patent Document 1 requires a highly sensitive current measurement means to measure minute leakage currents. In addition, the measurement results are easily affected by external noise.
  • the object of the present invention is to monitor the DC insulation resistance of a power distribution system using live lines without requiring highly sensitive current measurement means and without the measurement results being affected by external noise.
  • the DC insulation resistance monitoring system is a DC insulation resistance monitoring system that measures and monitors the DC insulation resistance of a power distribution system, and is characterized by having a grounded potential transformer, a neutral point switch of the grounded potential transformer, an insulating capacitor that is opened and closed by the neutral point switch, a DC power source that charges the insulating capacitor, a DC power supply switch that opens and closes the connection between the DC power source and the insulating capacitor, a switching control unit that controls the open and closed states of the neutral point switch and the DC power supply switch, respectively, and a voltage measuring unit that measures the voltage signal of the insulating capacitor.
  • a DC insulation resistance monitoring system does not require a highly sensitive current measurement means, and can monitor the DC insulation resistance of a live power distribution system without the measurement results being affected by external noise.
  • FIG. 1 is a diagram showing a DC insulation resistance monitoring system according to a first embodiment of the present invention
  • FIG. 4 is a diagram showing a voltage waveform of an insulation capacitor in the DC insulation resistance monitoring system according to the first embodiment.
  • FIG. 11 is a diagram showing another voltage waveform of the insulation capacitor of the DC insulation resistance monitoring system according to the first embodiment.
  • FIG. 4 is a diagram showing a voltage waveform of an insulating capacitor when a single-line ground fault occurs in a power distribution system during monitoring in the DC insulation resistance monitoring system of the first embodiment.
  • FIG. 4 is a diagram showing phase voltage waveforms when a single-line ground fault occurs in a power distribution system during monitoring by the DC insulation resistance monitoring system of the first embodiment.
  • Example 1 will be explained using Figures 1 to 6.
  • the power distribution system in which the DC insulation resistance is to be measured comprises a special high voltage transformer 1, a high voltage distribution panel 2, a high voltage incoming panel 3, a low voltage panel 4, and a high voltage transformer 5.
  • the high voltage distribution panel 2 is provided with a grounded voltage transformer 10.
  • An insulating capacitor 12 is inserted between the neutral point 100 of the grounded instrument transformer 10 and the ground, and the neutral point switch 11 is connected in parallel to the insulating capacitor 12.
  • a DC power supply 13 is connected to the insulating capacitor 12 via a DC power supply switch 14.
  • a voltage measuring unit 15 is provided to measure the voltage signal of the insulating capacitor 12.
  • the voltage signal is sent to a leakage resistance calculation unit 102, which calculates the leakage resistance R by dividing the decay time constant ⁇ of the voltage signal by the capacitance C of the insulating capacitor 12.
  • the leakage resistance is transferred to a leakage resistance display unit 103 and displayed.
  • the switching control unit 101 controls the open/closed state of the neutral point switch 11 and the DC power switch 14.
  • FIG. 2 is a diagram showing a voltage waveform of the insulating capacitor 12. As shown in FIG. As shown in FIG. 2, when the neutral point switch 11 is turned on by the switching control unit 101, the state transitions from the normal state to the DC insulation resistance measurement state.
  • the voltage waveform of the insulating capacitor 12 is superimposed with an induced voltage of commercial frequency, but the macro voltage change can be calculated by setting an appropriate interval and taking a moving average or by passing it through a low-pass filter.
  • the time constant ⁇ is determined by the product of the capacitance C of the insulating capacitor 12 and the leakage resistance R of the high-voltage distribution system. Therefore, if the time constant ⁇ is known, the leakage resistance value of the distribution system can be calculated.
  • the leakage resistance value calculated by the leakage resistance value calculation unit 102 is displayed on the leakage resistance value display unit 103. Thereafter, the neutral point switch 11 is turned OFF by the switching control unit 101, completing the DC insulation resistance measurement and ending the DC insulation resistance measurement state.
  • FIG. 3 shows a voltage waveform of the insulating capacitor 12 when the leakage resistance R of the high voltage distribution system is large. As shown in FIG. 3, when the neutral point switch 11 is turned on by the switching control unit 101, the state transitions from the normal state to the DC insulation resistance measurement state.
  • Figure 4 shows the voltage waveform of the insulating capacitor 12 when a single-line ground fault occurs in a high-voltage distribution system at 2 seconds while measuring the DC insulation resistance.
  • the voltage of the insulating capacitor 12 drops to -700V.
  • the phase voltage waveform of the system shows that between 2 and 2.1 seconds when a line-to-ground fault occurs, the voltage of the grounded phase drops and the voltage of the healthy phase increases by approximately 1.7 times.
  • Figure 6 shows the zero-phase voltage waveform measured with a grounded potential transformer.
  • the zero-phase voltage has the same waveform as in the normal state when the insulating capacitor 12 is short-circuited, so even if a single-line ground fault occurs in the high-voltage distribution system while measuring the DC insulation resistance, the fault can be detected.
  • this state can be achieved by setting the capacitance of the insulating capacitor 12 to 1 ⁇ F to 10 ⁇ F. If the capacitance of the insulating capacitor 12 is 1 ⁇ F or less, the reactance of the insulating capacitor 12 becomes large. As a result, the voltage share of the grounded potential transformer 10 in the series circuit of the grounded potential transformer 10 and the insulating capacitor 12 becomes small, so the zero-phase voltage signal becomes small and a ground fault cannot be detected.
  • the capacitance of the insulating capacitor 12 is 10 ⁇ F or more, the time constant ⁇ of the voltage drop of the insulating capacitor 12 becomes too large, making it difficult to measure the change in the leakage resistance value R of the power distribution system. For this reason, as a trade-off between the two, it is appropriate to set the capacitance C of the insulating capacitor 12 in the range of 1 ⁇ F to 10 ⁇ F.
  • the neutral point switch 11 is turned ON (open state) by the switching control section 101 (step 801).
  • the DC power supply switch is turned ON (open state) by the switching control section 101 (step 802).
  • the switching control unit 101 turns off (closed state) the DC power switch (step 804).
  • the voltage measurement unit 15 leaks the residual voltage of the insulating capacitor 12 (step 805).
  • the voltage change when the voltage measurement unit 15 leaks the residual voltage of the insulating capacitor 12 is stored (step 806).
  • the voltage measuring unit 15 calculates the voltage change rate from the voltage signal when the residual voltage of the insulating capacitor 12 is leaked (step 807).
  • the leakage resistance value calculating unit 102 calculates the leakage resistance value from the voltage change rate (step 808).
  • the leakage resistance value display unit 103 displays the leakage resistance value (step 809).
  • the neutral point switch 11 is turned OFF (opened) by the switching control unit 101 to complete the measurement of the DC insulation resistance (step 810).
  • the DC insulation resistance monitoring system does not require a highly sensitive current measuring means, and the DC insulation resistance of the power distribution system can be monitored live without the measurement results being affected by external noise.
  • the second embodiment shown in Fig. 7 differs from the first embodiment shown in Fig. 1 in that an overvoltage suppression means 16 for suppressing an overvoltage of the insulating capacitor 12 is newly added.
  • the other configurations are the same as those of the first embodiment shown in Fig. 1, so a description thereof will be omitted.
  • the overvoltage suppression means 16 is formed of, for example, a Zener diode or a zinc oxide type nonlinear resistor.
  • Example 2 it becomes possible to use a capacitor with a low rated voltage as the insulating capacitor 12.
  • the neutral point switch 11 is configured as a B contact (normally closed).
  • the other configurations are the same as those in the first embodiment shown in FIG. 1, so the description thereof will be omitted.
  • the neutral point of the grounded side instrument transformer 10 is grounded, so it is possible to maintain the function of detecting a single line ground fault in the power distribution system.
  • the neutral point of the instrument transformer is DC insulated by a capacitor, and the capacitor is charged to a certain value by a DC power source.
  • the DC power source is then disconnected, and the DC insulation resistance of the power distribution system is measured by measuring the time constant at which the voltage of the capacitor drops due to the leakage resistance of the power distribution system.
  • the DC insulation resistance monitoring system does not require a highly sensitive current measurement means, and the DC insulation resistance of the power distribution system can be monitored live without the measurement results being affected by external noise.

Abstract

The present invention comprises: an insulation capacitor that is opened and closed by the neutral-point switch of a transformer for a ground-type gauge; a DC power supply that charges the insulation capacitor; a DC power supply switch that opens and closes the connection between the DC power supply and the insulation capacitor; an open/close control unit that controls the open/close state of each of the neutral-point switch and the DC power supply switch; and a voltage measurement unit that measures the voltage signal of the insulation capacitor.

Description

直流絶縁抵抗監視システムDC insulation resistance monitoring system
　本発明は、直流絶縁抵抗監視システムに関する。 The present invention relates to a DC insulation resistance monitoring system.
　従来の配電系統の直流絶縁抵抗を測定する方法としては、配電系統を停電し、直流高圧電源を接続して、漏れ電流を測定する方法が一般的であった。これを改善するための直流絶縁抵抗監視システムとして、例えば特許文献１に記載のものがある。 　The conventional method for measuring the DC insulation resistance of a power distribution system was to shut down the power distribution system, connect a high-voltage DC power supply, and measure the leakage current. To improve on this, for example, there is a DC insulation resistance monitoring system described in Patent Document 1.
　特許文献１に記載のシステムでは、配電系統に接続されている接地形計器用変圧器の１次側中性点をコンデンサで直流的に絶縁し、その中性点に直流電源を接続して、流れる漏れ電流を測定することで、活線状態で配電系統の直流絶縁抵抗を測定している。 In the system described in Patent Document 1, the primary neutral point of a grounded instrument transformer connected to a power distribution system is DC insulated by a capacitor, a DC power source is connected to the neutral point, and the leakage current is measured to measure the DC insulation resistance of the power distribution system in a live state.
特開昭５８－５５８７０号公報Japanese Patent Application Laid-Open No. 58-55870
　特許文献１に記載の直流絶縁抵抗監視システムでは、微小な漏れ電流を測定するための高感度な電流測定手段が必要である。また、測定結果が外部ノイズの影響を受けやすい。 The DC insulation resistance monitoring system described in Patent Document 1 requires a highly sensitive current measurement means to measure minute leakage currents. In addition, the measurement results are easily affected by external noise.
　本発明の目的は、直流絶縁抵抗監視システムにおいて、高感度な電流測定手段が不要で、測定結果が外部ノイズの影響を受けずに活線で配電系統の直流絶縁抵抗を監視することにある。 The object of the present invention is to monitor the DC insulation resistance of a power distribution system using live lines without requiring highly sensitive current measurement means and without the measurement results being affected by external noise.
　本発明の一態様の直流絶縁抵抗監視システムは、配電系統の直流絶縁抵抗を測定して監視する直流絶縁抵抗監視システムであって、接地形計器用変圧器と、前記接地形計器用変圧器の中性点開閉器と、前記中性点用開閉器により開閉される絶縁用コンデンサと、前記絶縁用コンデンサを充電する直流電源と、前記直流電源と前記絶縁用コンデンサとの接続を開閉する直流電源開閉器と、前記中性点用開閉器と前記直流電源開閉器の開閉状態をそれぞれ制御する開閉制御部と、前記絶縁用コンデンサの電圧信号を測定する電圧測定部とを有することを特徴とする。 The DC insulation resistance monitoring system according to one embodiment of the present invention is a DC insulation resistance monitoring system that measures and monitors the DC insulation resistance of a power distribution system, and is characterized by having a grounded potential transformer, a neutral point switch of the grounded potential transformer, an insulating capacitor that is opened and closed by the neutral point switch, a DC power source that charges the insulating capacitor, a DC power supply switch that opens and closes the connection between the DC power source and the insulating capacitor, a switching control unit that controls the open and closed states of the neutral point switch and the DC power supply switch, respectively, and a voltage measuring unit that measures the voltage signal of the insulating capacitor.
　本発明の一態様によれば、直流絶縁抵抗監視システムにおいて、高感度な電流測定手段が不要で、測定結果が外部ノイズの影響を受けずに活線で配電系統の直流絶縁抵抗を監視することができる。 According to one aspect of the present invention, a DC insulation resistance monitoring system does not require a highly sensitive current measurement means, and can monitor the DC insulation resistance of a live power distribution system without the measurement results being affected by external noise.
実施例１の直流絶縁抵抗監視システムを示す図である。1 is a diagram showing a DC insulation resistance monitoring system according to a first embodiment of the present invention; 実施例１の直流絶縁抵抗監視システムの絶縁コンデンサの電圧波形を示す図である。FIG. 4 is a diagram showing a voltage waveform of an insulation capacitor in the DC insulation resistance monitoring system according to the first embodiment. 実施例１の直流絶縁抵抗監視システムの絶縁コンデンサのもう一つの電圧波形を示す図である。FIG. 11 is a diagram showing another voltage waveform of the insulation capacitor of the DC insulation resistance monitoring system according to the first embodiment. 実施例１の直流絶縁抵抗監視システムで、監視中に配電系統に一線地絡が発生したときの絶縁コンデンサの電圧波形を示す図である。FIG. 4 is a diagram showing a voltage waveform of an insulating capacitor when a single-line ground fault occurs in a power distribution system during monitoring in the DC insulation resistance monitoring system of the first embodiment. 実施例１の直流絶縁抵抗監視システムで、監視中に配電系統に一線地絡が発生したときの相電圧波形を示す図である。FIG. 4 is a diagram showing phase voltage waveforms when a single-line ground fault occurs in a power distribution system during monitoring by the DC insulation resistance monitoring system of the first embodiment. 実施例１の直流絶縁抵抗監視システムで、監視中に配電系統に一線地絡が発生したときの接地形計器用変圧器で測定した系統電圧の零相電圧波形を示す図である。FIG. 10 is a diagram showing a zero-phase voltage waveform of a system voltage measured by a grounded potential transformer when a single-line ground fault occurs in a power distribution system during monitoring in the DC insulation resistance monitoring system of the first embodiment. 実施例２の直流絶縁抵抗監視システムを示す図である。FIG. 11 is a diagram showing a DC insulation resistance monitoring system according to a second embodiment. 本発明の動作を説明するためのフロー図である。FIG. 4 is a flow chart for explaining the operation of the present invention.
　以下、本発明を実施する上で好適となる実施例について図面を用いて説明する。尚、下記はあくまでも実施の例に過ぎず、発明の内容が下記具体的態様に限定されるものではない。本発明は、下記態様を含めて種々の態様に変形することが無論可能である。以下、図面を用いて実施例について説明する。 Below, preferred embodiments of the present invention will be described with reference to the drawings. Note that the following are merely examples of the present invention, and the invention is not limited to the specific embodiments described below. The present invention can of course be modified into various forms, including the embodiments described below. Below, preferred embodiments will be described with reference to the drawings.
　実施例１について図１から図６を用いて説明する。 Example 1 will be explained using Figures 1 to 6.
　まず、図１を参照して、実施例１の直流絶縁抵抗監視システムについて説明する。
  直流絶縁抵抗を測定する配電系統は、特高変圧器１、高圧配電盤２、高圧受電盤３、低圧盤４及び高圧変圧器５から構成される。高圧配電盤２は接地形計器用変圧器１０を備える。 First, a DC insulation resistance monitoring system according to a first embodiment will be described with reference to FIG.
The power distribution system in which the DC insulation resistance is to be measured comprises a special high voltage transformer 1, a high voltage distribution panel 2, a high voltage incoming panel 3, a low voltage panel 4, and a high voltage transformer 5. The high voltage distribution panel 2 is provided with a grounded voltage transformer 10.
　接地形計器用変圧器１０の中性点１００と接地の間に絶縁用コンデンサ１２を挿入し、中性点開閉器１１を絶縁用コンデンサ１２に並列に接続する。また、直流電源１３を、直流電源開閉器１４を介して絶縁用コンデンサ１２に接続する。 An insulating capacitor 12 is inserted between the neutral point 100 of the grounded instrument transformer 10 and the ground, and the neutral point switch 11 is connected in parallel to the insulating capacitor 12. In addition, a DC power supply 13 is connected to the insulating capacitor 12 via a DC power supply switch 14.
　絶縁用コンデンサ１２の電圧信号を測定するために、電圧測定部１５を備える。電圧信号は漏れ抵抗値計算部１０２に送られ、電圧信号の減衰時定数τを絶縁用コンデンサ１２の静電容量Ｃで除することにより漏れ抵抗値Ｒを計算する。漏れ抵抗値は漏れ抵抗値表示部１０３に転送されて表示される。開閉制御部１０１は中性点開閉器１１と直流電源開閉器１４の開閉状態をそれぞれ制御する。 A voltage measuring unit 15 is provided to measure the voltage signal of the insulating capacitor 12. The voltage signal is sent to a leakage resistance calculation unit 102, which calculates the leakage resistance R by dividing the decay time constant τ of the voltage signal by the capacitance C of the insulating capacitor 12. The leakage resistance is transferred to a leakage resistance display unit 103 and displayed. The switching control unit 101 controls the open/closed state of the neutral point switch 11 and the DC power switch 14.
　図２は、絶縁用コンデンサ１２の電圧波形を示す図である。
  図２に示すように、開閉制御部１０１により中性点開閉器１１をＯＮにすることにより、通常状態から直流絶縁抵抗測定状態に移行する。 FIG. 2 is a diagram showing a voltage waveform of the insulating capacitor 12. As shown in FIG.
As shown in FIG. 2, when the neutral point switch 11 is turned on by the switching control unit 101, the state transitions from the normal state to the DC insulation resistance measurement state.
　絶縁用コンデンサ１２の電圧波形には、商用周波数の誘導電圧が重畳するが、適切な区間を設定して移動平均するか、ローパスフィルタを通すことによりマクロな電圧変化を計算することができる。 The voltage waveform of the insulating capacitor 12 is superimposed with an induced voltage of commercial frequency, but the macro voltage change can be calculated by setting an appropriate interval and taking a moving average or by passing it through a low-pass filter.
　その時定数τは絶縁用コンデンサ１２の静電容量Ｃと高圧配電系統の漏れ抵抗Ｒの積で決まる。このため、時定数τが分かれば配電系統の漏れ抵抗値を計算することができる。漏れ抵抗値計算部１０２で計算された漏れ抵抗値は漏れ抵抗値表示部１０３で表示される。その後、開閉制御部１０１により中性点開閉器１１をＯＦＦにすることにより直流絶縁抵抗測定が完了して直流絶縁抵抗測定状態が終了する。 The time constant τ is determined by the product of the capacitance C of the insulating capacitor 12 and the leakage resistance R of the high-voltage distribution system. Therefore, if the time constant τ is known, the leakage resistance value of the distribution system can be calculated. The leakage resistance value calculated by the leakage resistance value calculation unit 102 is displayed on the leakage resistance value display unit 103. Thereafter, the neutral point switch 11 is turned OFF by the switching control unit 101, completing the DC insulation resistance measurement and ending the DC insulation resistance measurement state.
　図３は、高圧配電系統の漏れ抵抗Ｒが大きい場合の絶縁用コンデンサ１２の電圧波形である。
  図３に示すように、開閉制御部１０１により中性点開閉器１１をＯＮにすることにより、通常状態から直流絶縁抵抗測定状態に移行する。 FIG. 3 shows a voltage waveform of the insulating capacitor 12 when the leakage resistance R of the high voltage distribution system is large.
As shown in FIG. 3, when the neutral point switch 11 is turned on by the switching control unit 101, the state transitions from the normal state to the DC insulation resistance measurement state.
　放電時定数τが大きくなるため、絶縁用コンデンサ１２の電圧波形はほぼ一定の値を示す。 Because the discharge time constant τ becomes large, the voltage waveform of the insulating capacitor 12 shows an almost constant value.
　以上より、絶縁用コンデンサ１２の電圧変化を測定することにより、高感度な電流測定手段を備えなくても、高圧配電系統の漏れ抵抗値Ｒの変化を活線で監視することができる。また、絶縁用コンデンサ１２の電圧波形は外部ノイズの影響を受けにくいため、正確に高圧配電系統の漏れ抵抗値を測定することができる。 As described above, by measuring the voltage change of the insulating capacitor 12, it is possible to monitor the change in the leakage resistance value R of the high-voltage distribution system on a live line without having to provide a highly sensitive current measurement means. In addition, since the voltage waveform of the insulating capacitor 12 is not easily affected by external noise, it is possible to accurately measure the leakage resistance value of the high-voltage distribution system.
　図４は、直流絶縁抵抗を測定中の時刻２秒において、高圧配電系統で一線地絡が発生した場合の、絶縁用コンデンサ１２の電圧波形を示す。一線地絡が発生すると、絶縁コンデンサ１２の電圧が－７００Ｖに低下する。 Figure 4 shows the voltage waveform of the insulating capacitor 12 when a single-line ground fault occurs in a high-voltage distribution system at 2 seconds while measuring the DC insulation resistance. When a single-line ground fault occurs, the voltage of the insulating capacitor 12 drops to -700V.
　図５は、系統の相電圧波形で一線地絡が発生している時刻２秒から２．１秒の間は、地絡相の電圧が低下し健全相の電圧がおよそ１．７倍に増加する。 In Figure 5, the phase voltage waveform of the system shows that between 2 and 2.1 seconds when a line-to-ground fault occurs, the voltage of the grounded phase drops and the voltage of the healthy phase increases by approximately 1.7 times.
　図６は、接地形計器用変圧器で測定した零相電圧波形を示す。零相電圧は、絶縁用コンデンサ１２を短絡している通常状態の波形と同じであり、直流絶縁抵抗を測定している途中で、高圧配電系統で一線地絡が発生しても、その事故検出が可能である。 Figure 6 shows the zero-phase voltage waveform measured with a grounded potential transformer. The zero-phase voltage has the same waveform as in the normal state when the insulating capacitor 12 is short-circuited, so even if a single-line ground fault occurs in the high-voltage distribution system while measuring the DC insulation resistance, the fault can be detected.
　この状態は、絶縁用コンデンサ１２の静電容量を１μＦ～１０μＦに設定することで実現できることを回路解析で確認した。絶縁用コンデンサ１２の静電容量が１μＦ以下では、絶縁用コンデンサ１２のリアクタンスが大きくなる。その結果、接地形計器用変圧器１０と絶縁用コンデンサ１２の直列回路における接地形計器用変圧器１０の電圧分担率が小さくなるため、零相電圧信号が小さくなって、地絡が検出できなくなる。 It was confirmed by circuit analysis that this state can be achieved by setting the capacitance of the insulating capacitor 12 to 1 μF to 10 μF. If the capacitance of the insulating capacitor 12 is 1 μF or less, the reactance of the insulating capacitor 12 becomes large. As a result, the voltage share of the grounded potential transformer 10 in the series circuit of the grounded potential transformer 10 and the insulating capacitor 12 becomes small, so the zero-phase voltage signal becomes small and a ground fault cannot be detected.
　一方、絶縁コンデンサ１２の静電容量が１０μＦ以上では、絶縁コンデンサ１２の電圧低下の時定数τが大きくなりすぎて、配電系統の漏れ抵抗値Ｒの変化が測定しにくくなる。このため、両者のトレードオフとして絶縁用コンデンサ１２の静電容量Ｃを１μＦ～１０μＦの範囲に設定することが適切である。 On the other hand, if the capacitance of the insulating capacitor 12 is 10 μF or more, the time constant τ of the voltage drop of the insulating capacitor 12 becomes too large, making it difficult to measure the change in the leakage resistance value R of the power distribution system. For this reason, as a trade-off between the two, it is appropriate to set the capacitance C of the insulating capacitor 12 in the range of 1 μF to 10 μF.
　また、絶縁コンデンサ１２の充電電圧を１０Ｖ程度に設定すれば、接地形計器用変圧器の１０の偏磁を含め、他のシステムへの影響が無視できることを確認した。 It was also confirmed that if the charging voltage of the insulating capacitor 12 is set to approximately 10V, the impact on other systems, including the bias magnetism of the grounded potential transformer 10, can be ignored.
　図８を参照して、配電系統の直流絶縁抵抗を測定する際の動作を説明する。
  最初に、開閉制御部１０１により中性点開閉器１１をＯＮ（開状態）にする（ステップ８０１）。次に、開閉制御部１０１により直流電源開閉器をＯＮ（開状態）する（ステップ８０２）。 The operation of measuring the DC insulation resistance of a power distribution system will be described with reference to FIG.
First, the neutral point switch 11 is turned ON (open state) by the switching control section 101 (step 801). Next, the DC power supply switch is turned ON (open state) by the switching control section 101 (step 802).
　次に、絶縁コンデンサを充電する（ステップ８０３）。次に、開閉制御部１０１により直流電源開閉器をＯＦＦ（閉状態）にする（ステップ８０４）。 Then, the insulating capacitor is charged (step 803). Next, the switching control unit 101 turns off (closed state) the DC power switch (step 804).
　次に、電圧測定部１５により絶縁コンデンサ１２の残留電圧をリークさせる（ステップ８０５）。次に、電圧測定部１５により絶縁コンデンサ１２の残留電圧をリークさせたときの電圧変化を記憶する（ステップ８０６）。 Next, the voltage measurement unit 15 leaks the residual voltage of the insulating capacitor 12 (step 805). Next, the voltage change when the voltage measurement unit 15 leaks the residual voltage of the insulating capacitor 12 is stored (step 806).
　次に、電圧測定部１５により絶縁コンデンサ１２の残留電圧をリークさせたときの電圧信号から電圧変化率を計算する（ステップ８０７）。次に、漏れ抵抗値計算部１０２により電圧変化率から漏れ抵抗値を計算する（ステップ８０８）。次に、漏れ抵抗値表示部１０３により漏れ抵抗値を表示する（ステップ８０９）。 Then, the voltage measuring unit 15 calculates the voltage change rate from the voltage signal when the residual voltage of the insulating capacitor 12 is leaked (step 807). Next, the leakage resistance value calculating unit 102 calculates the leakage resistance value from the voltage change rate (step 808). Next, the leakage resistance value display unit 103 displays the leakage resistance value (step 809).
　最後に、開閉制御部１０１により中性点開閉器１１をＯＦＦ（開状態）にして、直流絶縁抵抗の測定を完了させる（ステップ８１０）。 Finally, the neutral point switch 11 is turned OFF (opened) by the switching control unit 101 to complete the measurement of the DC insulation resistance (step 810).
　実施例１によれば、直流絶縁抵抗監視システムにおいて、高感度な電流測定手段が不要で、測定結果が外部ノイズの影響を受けずに活線で配電系統の直流絶縁抵抗を監視することができる。 According to the first embodiment, the DC insulation resistance monitoring system does not require a highly sensitive current measuring means, and the DC insulation resistance of the power distribution system can be monitored live without the measurement results being affected by external noise.
　図７を参照して、実施例２の直流絶縁抵抗監視システムについて説明する。
  図７に示す実施例２が図１に示す実施例１と異なる点は、絶縁用コンデンサ１２の過電圧を抑制するための過電圧抑制手段１６を新たに追加した点である。その他の構成は、図１に示す実施例１と同じなのでその説明は省略する。過電圧抑制手段１６は、例えば、ツェナーダイオードや酸化亜鉛形非線形抵抗などにより構成される。 Second Embodiment A DC insulation resistance monitoring system according to a second embodiment will be described with reference to FIG.
The second embodiment shown in Fig. 7 differs from the first embodiment shown in Fig. 1 in that an overvoltage suppression means 16 for suppressing an overvoltage of the insulating capacitor 12 is newly added. The other configurations are the same as those of the first embodiment shown in Fig. 1, so a description thereof will be omitted. The overvoltage suppression means 16 is formed of, for example, a Zener diode or a zinc oxide type nonlinear resistor.
　実施例２によれば、定格電圧が低いコンデンサを絶縁用コンデンサ１２に適用することが可能になる。 According to Example 2, it becomes possible to use a capacitor with a low rated voltage as the insulating capacitor 12.
　実施例３の直流絶縁抵抗監視システムについて説明する。
  実施例３では、中性点開閉器１１をＢ接点（常時閉）で構成している。
  その他の構成は、図１に示す実施例１と同じなのでその説明は省略する。 Third Embodiment A DC insulation resistance monitoring system according to a third embodiment will be described.
In the third embodiment, the neutral point switch 11 is configured as a B contact (normally closed).
The other configurations are the same as those in the first embodiment shown in FIG. 1, so the description thereof will be omitted.
　実施例３によれば、中性点開閉器１１の操作回路が故障しても、接地側計器用変圧器１０の中性点が接地されるため、配電系統の一線地絡を検出する機能を維持することが可能になる。 According to the third embodiment, even if the operating circuit of the neutral point switch 11 fails, the neutral point of the grounded side instrument transformer 10 is grounded, so it is possible to maintain the function of detecting a single line ground fault in the power distribution system.
　上記実施例では、計器用変圧器の中性点をコンデンサで直流的に絶縁し、そのコンデンサを直流電源で一定の値に充電した後で、直流電源を切り離し、配電系統の漏れ抵抗によってコンデンサの電圧が低下する時定数を測定することにより配電系統の直流絶縁抵抗を測定する。 In the above example, the neutral point of the instrument transformer is DC insulated by a capacitor, and the capacitor is charged to a certain value by a DC power source. The DC power source is then disconnected, and the DC insulation resistance of the power distribution system is measured by measuring the time constant at which the voltage of the capacitor drops due to the leakage resistance of the power distribution system.
　上記実施例によれば、直流絶縁抵抗監視システムにおいて、高感度な電流測定手段が不要で、測定結果が外部ノイズの影響を受けずに活線で配電系統の直流絶縁抵抗を監視することができる。 According to the above embodiment, the DC insulation resistance monitoring system does not require a highly sensitive current measurement means, and the DC insulation resistance of the power distribution system can be monitored live without the measurement results being affected by external noise.
１　特高変圧器
２　高圧配電盤
３　高圧受電盤
４　低圧盤
５　高圧変圧器
１０　接地形計器用変圧器
１１　中性点開閉器
１２　絶縁用コンデンサ
１３　直流電源
１４　直流電源開閉器
１５　電圧測定部
１６　過電圧抑制手段
１０１　開閉制御部
１０２　漏れ抵抗値計算部
１０３　漏れ抵抗値表示部 REFERENCE SIGNS LIST 1 Extra-high voltage transformer 2 High-voltage distribution board 3 High-voltage incoming board 4 Low-voltage board 5 High-voltage transformer 10 Earthed instrument transformer 11 Neutral point switch 12 Insulating capacitor 13 DC power supply 14 DC power supply switch 15 Voltage measurement unit 16 Overvoltage suppression means 101 Switching control unit 102 Leakage resistance value calculation unit 103 Leakage resistance value display unit

Claims (10)

  1. 　配電系統の直流絶縁抵抗を測定して監視する直流絶縁抵抗監視システムであって、
    　接地形計器用変圧器と、
    　前記接地形計器用変圧器の中性点開閉器と、
    　前記中性点用開閉器により開閉される絶縁用コンデンサと、
    　前記絶縁用コンデンサを充電する直流電源と、
    　前記直流電源と前記絶縁用コンデンサとの接続を開閉する直流電源開閉器と、
    　前記中性点用開閉器と前記直流電源開閉器の開閉状態をそれぞれ制御する開閉制御部と、
    　前記絶縁用コンデンサの電圧信号を測定する電圧測定部と、
    　を有することを特徴とする直流絶縁抵抗監視システム。     A DC insulation resistance monitoring system for measuring and monitoring DC insulation resistance of a power distribution system, comprising:
    A grounded potential transformer;
    a neutral switch of the grounding type instrument transformer;
    an insulating capacitor that is switched by the neutral point switch;
    a DC power source for charging the insulating capacitor;
    a DC power supply switch that opens and closes a connection between the DC power supply and the insulating capacitor;
    a switching control unit that controls the open/closed states of the neutral point switch and the DC power switch, respectively;
    a voltage measuring unit for measuring a voltage signal of the insulating capacitor;
    A DC insulation resistance monitoring system comprising:
  2. 　前記接地形計器用変圧器の中性点と接地の間に前記絶縁用コンデンサが挿入されており、前記接地形計器用変圧器の前記中性点が前記絶縁用コンデンサで直流的に絶縁されており、
    　前記開閉制御部は、
    　前記直流電源開閉器を開状態にして前記絶縁用コンデンサを前記直流電源で一定の値に充電した後で、前記直流電源開閉器を閉状態にして前記直流電源を切り離し、
    　前記電圧測定部は、
    　前記配電系統の漏れ抵抗によって前記絶縁用コンデンサの前記電圧信号が低下する減衰時定数を測定することにより、前記配電系統の前記直流絶縁抵抗を測定することを特徴とする請求項１に記載の直流絶縁抵抗監視システム。     the insulating capacitor is inserted between the neutral point of the grounded potential transformer and ground, and the neutral point of the grounded potential transformer is DC-insulated by the insulating capacitor;
    The opening/closing control unit is
    After the DC power supply switch is opened and the insulating capacitor is charged to a certain value by the DC power supply, the DC power supply switch is closed to disconnect the DC power supply;
    The voltage measurement unit is
    2. The DC insulation resistance monitoring system according to claim 1, wherein the DC insulation resistance of the power distribution system is measured by measuring a decay time constant at which the voltage signal of the insulating capacitor decreases due to leakage resistance of the power distribution system.
  3. 　前記電圧信号の前記減衰時定数と前記絶縁用コンデンサの静電容量を用いて前記漏れ抵抗の漏れ抵抗値を計算する漏れ抵抗値計算部と、
    　前記漏れ抵抗値を表示する漏れ抵抗値表示部と、
    　を更に有することを特徴とする請求項２に記載の高圧配電系統の直流絶縁抵抗監視システム。     a leakage resistance value calculation unit that calculates a leakage resistance value of the leakage resistor using the attenuation time constant of the voltage signal and the capacitance of the insulating capacitor;
    A leakage resistance value display unit that displays the leakage resistance value;
    3. The DC insulation resistance monitoring system for a high voltage power distribution system according to claim 2, further comprising:
  4. 　前記漏れ抵抗値計算部は、
    　前記電圧信号の前記減衰時定数を前記絶縁用コンデンサの前記静電容量で除することにより前記漏れ抵抗値を計算することを特徴とする請求項３に記載の直流絶縁抵抗監視システム。     The leakage resistance value calculation unit
    4. The DC insulation resistance monitoring system according to claim 3, wherein the leakage resistance value is calculated by dividing the decay time constant of the voltage signal by the capacitance of the insulating capacitor.
  5. 　前記絶縁用コンデンサの前記静電容量は、１μＦから１０μＦの範囲内に設定されていることを特徴とする請求項３に記載の直流絶縁抵抗監視システム。 The DC insulation resistance monitoring system according to claim 3, characterized in that the capacitance of the insulating capacitor is set within the range of 1 μF to 10 μF.
  6. 　前記配電系統の前記直流絶縁抵抗を測定する際に、
    　前記開閉制御部は、
    　前記中性点開閉器と前記直流電源開閉器を開状態にして前記絶縁コンデンサを充電し、前記絶縁コンデンサを充電した後に前記直流電源開閉器を閉状態し、
    　前記電圧測定部は、
    　前記絶縁コンデンサの残留電圧をリークさせたときの前記電圧信号から電圧変化率を計算し、
    　前記漏れ抵抗値計算部は、
    　前記電圧変化率から前記漏れ抵抗値を計算し、
    　前記開閉制御部は、
    　前記漏れ抵抗値表示部により前記漏れ抵抗値を表示した後に前記中性点開閉器を閉状態にして、前記直流絶縁抵抗の測定を完了させることを特徴とする請求項３に記載の直流絶縁抵抗監視システム。     When measuring the DC insulation resistance of the power distribution system,
    The opening/closing control unit is
    charging the insulation capacitor with the neutral point switch and the DC power switch in an open state, and closing the DC power switch after the insulation capacitor is charged;
    The voltage measurement unit is
    calculating a voltage change rate from the voltage signal when a residual voltage of the insulating capacitor is leaked;
    The leakage resistance value calculation unit
    Calculating the leakage resistance value from the voltage change rate;
    The opening/closing control unit is
    4. The DC insulation resistance monitoring system according to claim 3, wherein the neutral contact switch is closed after the leakage resistance value display unit displays the leakage resistance value, thereby completing the measurement of the DC insulation resistance.
  7. 　前記配電系統は、
    　特高変圧器、高圧配電盤、高圧受電盤、低圧盤及び高圧変圧器を有し、
    　前記高圧配電盤は前記接地形計器用変圧器を備えることを特徴とする請求項１に記載の直流絶縁抵抗監視システム。     The power distribution system includes:
    It has a special high-voltage transformer, a high-voltage distribution board, a high-voltage receiving board, a low-voltage board and a high-voltage transformer.
    2. The DC insulation resistance monitoring system according to claim 1, wherein the high-voltage switchboard is provided with the grounded potential transformer.
  8. 　前記絶縁用コンデンサの過電圧を抑制するための過電圧抑制手段を更に有することを特徴とする請求項１に記載の直流絶縁抵抗監視システム。 The DC insulation resistance monitoring system according to claim 1, further comprising an overvoltage suppression means for suppressing an overvoltage of the insulating capacitor.
  9. 　前記過電圧抑制手段は、ツェナーダイオード又は酸化亜鉛形非線形抵抗で構成されることを特徴とする請求項８に記載の直流絶縁抵抗監視システム。 The DC insulation resistance monitoring system according to claim 8, characterized in that the overvoltage suppression means is composed of a Zener diode or a zinc oxide type nonlinear resistor.
  10. 　前記中性電用開閉器は、常時閉接点で構成されることを特徴とする請求項１に記載の直流絶縁抵抗監視システム。 The DC insulation resistance monitoring system described in claim 1, characterized in that the neutral current switch is composed of a normally closed contact.
PCT/JP2023/007584 2022-10-13 2023-03-01 Dc insulation resistance monitoring system WO2024079922A1 (en)

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS52105871A (en) * 1976-03-02 1977-09-05 Sumitomo Electric Ind Ltd Method of impressing dc voltage to high-tension distribution line
JPS5467688A (en) * 1977-11-09 1979-05-31 Sumitomo Electric Ind Ltd Method of applying voltage for monitoring power cable insulation
JPS6078359A (en) * 1983-10-05 1985-05-04 Hitachi Ltd Static leonard device
JP2007292686A (en) * 2006-04-27 2007-11-08 Harada Sangyo Kk Resistance measuring device and method

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS52105871A (en) * 1976-03-02 1977-09-05 Sumitomo Electric Ind Ltd Method of impressing dc voltage to high-tension distribution line
JPS5467688A (en) * 1977-11-09 1979-05-31 Sumitomo Electric Ind Ltd Method of applying voltage for monitoring power cable insulation
JPS6078359A (en) * 1983-10-05 1985-05-04 Hitachi Ltd Static leonard device
JP2007292686A (en) * 2006-04-27 2007-11-08 Harada Sangyo Kk Resistance measuring device and method

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