JP7270945B2 - Leakage current interrupter - Google Patents

Description

The present invention relates to a leakage current interrupting device.

2. Description of the Related Art Conventionally, there is known a leakage current interrupting device for interrupting a leakage current I in a wire line to be measured (see Patent Document 1). The leakage current I includes a leakage current component Igc caused by the ground capacitance and a leakage current component Igr caused by the ground insulation resistance directly related to the insulation resistance. Since a so-called electric leakage fire is caused by insulation resistance, the insulation state of the cable under test can be checked by the leakage current component Igr caused by the insulation resistance.

JP 2013-174613 A

However, in Patent Literature 1, when the leakage current component Igr exceeds a predetermined value, the leakage state is not reported and the leak is uniformly cut off, so the risk of leakage cannot be detected before the cutoff.

Therefore, an object of the present invention is to provide a leakage current interrupting device that notifies the possibility of leakage before interruption.

As means for solving the above-mentioned problems, the present invention provides a leakage current detection section for detecting a leakage current flowing through an electric line to be measured, and a voltage detection section for detecting a voltage applied to the electric line to be measured. a phase difference detection unit for detecting a phase difference between a signal waveform of the leakage current detected by the leakage current detection unit and a signal waveform of the voltage detected by the voltage detection unit; and a voltage signal detected by the voltage detection unit. Based on the waveform, a power frequency measuring unit that measures the power frequency applied to the cable under test, the phase difference detected by the phase difference detecting unit, and the power frequency measured by the power frequency measuring unit. Based on the phase angle calculation unit for calculating the phase angle of the leakage current flowing in the electric line under test, the leakage current detected by the leakage current detection unit, and the phase angle calculated by the phase angle calculation unit a ground insulation resistance leakage current component calculation unit for calculating a leakage current component Igr caused by the ground insulation resistance contained in the leakage current, and a leakage current component Igr calculated by the ground insulation resistance leakage current component calculation unit. a judging section for judging the leakage state of the electric line under test based on the A reporting unit that reports the leakage state determined by the determination unit, a humidity detection unit that detects humidity , and a ventilation unit that ventilates the surroundings of the electric line to be measured. If it is equal to or higher than the leakage threshold value that is determined to be leaking, it is determined that the cable under test is leaking. As the humidity detected by the humidity detection unit increases, the humidity is corrected to decrease, and when the leakage current component Igr is equal to or higher than the corrected leakage risk threshold value, it is determined that there is a risk of leakage from the electric line to be measured. When the determination unit determines that there is a risk of leakage from the electric line under test, the notification unit notifies a leakage risk signal corresponding to the possibility of leakage from the electric line under test , and the ventilation unit. is a leakage current interrupting device characterized by initiating ventilation .
Further, when the determination unit determines that the leakage current component Igr has decreased below the leakage risk threshold while the notification unit reports the leakage risk signal and the ventilation unit is ventilating, the notification unit issues a leakage risk signal. A configuration may be adopted in which the notification of the signal is stopped and the ventilation unit stops ventilation.

According to such a configuration, when the leakage current component Igr is equal to or greater than the leakage threshold, the judging section judges that the electric line under test is leaking, and the breaking section cuts off the electric line under measurement. Then, when the leakage current component Igr is equal to or greater than the leakage risk threshold value, the determination unit determines that there is a risk of leakage from the wire line under test, and the reporting unit determines that there is a risk of leakage from the wire line under test. broadcast a signal. In this manner, the risk of leakage can be notified before the wire line to be measured is cut off.

In addition, since the determination unit corrects the leakage risk threshold to be smaller as the humidity detected by the humidity detection unit increases, it is possible to accurately determine whether there is a risk of leakage. Here, the higher the humidity, the easier it is to leak.
According to such a configuration, when the determining unit determines that the leakage current component Igr has decreased below the leakage potential threshold while the reporting unit is reporting the potential leakage signal, the reporting unit issues the potential leakage signal. can be stopped.

Further, a use time detection unit for detecting the use time of the cable under test is provided, and the determination unit corrects the leakage risk threshold so as to decrease as the use time detected by the use time detection unit increases. may be configured.

According to such a configuration, the judging section corrects the leakage risk threshold to be smaller as the usage time of the cable under test detected by the usage time detecting section increases. can be determined accurately. Here, leakage becomes more likely as the use time of the cable under test increases.

Further, a temperature detection unit that detects temperature may be provided, and the determination unit may correct the leakage risk threshold value so as to decrease as the temperature difference in a predetermined time based on the temperature detected by the temperature detection unit increases. good.

According to this configuration, as the temperature difference in the predetermined time based on the temperature detected by the temperature detection unit increases, the determination unit corrects the leakage risk threshold value so as to decrease. can be determined accurately. Here, leakage becomes easier as the temperature difference in a predetermined time increases.

Further, a ground height setting unit for setting a ground height is provided, and the determination unit reduces the leakage risk threshold as the ground height set in the ground height setting unit decreases. It is good also as a structure which correct|amends.

According to this configuration, as the ground height set in the ground height setting unit decreases, the determination unit corrects the leakage risk threshold value to decrease. can be determined. Here, as the height above the ground becomes smaller, dew condensation is more likely to occur, and thus leakage is more likely to occur.

Further, a configuration may be provided in which a display section for displaying at least one of the leakage current component Igr, the leakage threshold, and the potential leakage threshold is provided.

According to such a configuration, the display section can display at least one of the leakage current component Igr, the leakage threshold, and the potential leakage threshold.

Moreover, it is good also as a structure provided with the external notification part which reports the leakage state determined by the said determination part, and the leakage state determined by the determination part which comprises another leakage current interruption|blocking apparatus.

The judging unit judges the risk of leakage in the electric line under test in a plurality of stages based on a plurality of leakage risk thresholds corresponding to the degree of the possibility of leakage in the electric line under test, and the reporting unit A configuration may be adopted in which a leakage fear signal is notified in response to a stage where there is a risk of leakage from the electric line to be measured.

According to such a configuration, the judging section judges the risk of leakage in the electric line under test in a plurality of stages based on the plurality of leakage risk thresholds corresponding to the degree of the risk of leakage in the electric line under test, and the reporting section However, it is possible to issue a leakage risk signal corresponding to the stage where there is a risk that the cable under test will leak.

ADVANTAGE OF THE INVENTION According to this invention, the leak current interruption|blocking apparatus which alert|reports a possibility of leakage before interruption|blocking can be provided.

1 is a block diagram showing the configuration of a leakage current interrupting device according to this embodiment; FIG. FIG. 4 is a diagram showing a phase difference between a leakage current component Igr caused by the ground insulation resistance and a leakage current component Igc caused by the ground capacitance when the power source is a single-phase system; FIG. 4 is a diagram showing a phase difference between a leakage current component Igr due to ground insulation resistance and a leakage current component Igc due to ground capacitance when the power supply is of a three-phase type; FIG. 10 is a diagram showing waveforms between R phase and S phase, between S phase and T phase, and between T phase and R phase with phases different by 120° when the power supply is of a three-phase type; FIG. 4 is a diagram in which the voltage between the R phase and the T phase is inverted when the power supply is of a three-phase type; FIG. 4 is a diagram showing a case where only a leakage current component Igr (R-phase Igr) is generated in the R-phase and only a leakage current component Igr (T-phase Igr) is generated in the T-phase when the power supply is of a three-phase type; . FIG. 4 is a diagram showing a case where only a leakage current component Igc (R-phase Igc) is generated in the R-phase and only a leakage current component Igc (T-phase Igc) is generated in the T-phase when the power supply is of a three-phase type; . FIG. 4 is a diagram showing a case where a three-phase power supply has a leakage current component Igr and a leakage current component Igc in the R phase and a leakage current component Igr and a leakage current component Igc in the T phase; . FIG. 10 is a diagram showing, in vectors, waveforms between the R phase and the S phase, between the S phase and the T phase, and between the T phase and the R phase in which the phases differ by 120° when the power supply is of a three-phase type; FIG. 4 is a single-phase vector diagram in which a reference point a is obtained from the voltage detected between the R-phase and the T-phase when the power supply is of the three-phase type; FIG. 4 is a vector diagram for obtaining a combined vector Igc of R-phase Igc and T-phase Igc at a position 180° (0°) from a reference point a when the power source is a single-phase type; FIG. 4 is a vector diagram showing a combined vector (leakage current I0) of R-phase Igr and Igc when only R-phase Igr is generated in a three-phase power supply; FIG. 4 is a vector diagram showing a combined vector (leakage current I0) of T-phase Igr and Igc when only T-phase Igr is generated in a three-phase power supply; FIG. 4 is a diagram showing a phase difference between a converted voltage V1 and a voltage V2 that are input to a comparator; FIG. 10 is a diagram showing a waveform of a converted voltage V1 input to a comparator and a waveform of a square wave converted based on the converted voltage V1; FIG. 10 is a diagram showing a waveform of a voltage V2 input to a comparator and a waveform of a square wave converted based on the voltage V2; FIG. 6B is a diagram showing a waveform when square wave conversion is performed based on the converted voltage V1 of FIG. 6A and a waveform formed when EXOR is performed based on the waveform when square wave conversion is performed based on the voltage V2 of FIG. 6B. It is a flow chart which shows operation of the leakage current interruption device concerning this embodiment. 4 is a map (graph) showing the relationship between the ground height of the leakage current interrupting device according to the present embodiment, the first leakage risk threshold, the second leakage risk threshold, and the leakage threshold. 4 is a map (graph) showing the relationship between the usage time of the leakage current interrupting device according to the present embodiment and the correction coefficient. 4 is a map (graph) showing the relationship between the ambient humidity of the leakage current interrupting device according to the present embodiment and the correction coefficient. 4 is a map (graph) showing the relationship between the temperature difference around the leakage current interrupting device according to the present embodiment and the correction coefficient. It is a time chart which shows one operation example of the leakage current interruption device which concerns on this embodiment.

An embodiment of the present invention will be described with reference to FIGS. 1-13.

<<Configuration of Leakage Current Breaker>>
As shown in FIG. 1, the leakage current interrupting device 1 includes a CT sensor section 10 (current transformer sensor section, leakage current detection section), an amplifier section 11, an LPF 12 (low pass filter), a full wave rectification section 13, Voltage detection unit 14, transformation unit 15, LPF 16 (low-pass filter), full-wave rectification unit 17, comparison unit 18, calculation unit 19, phase pulse width measurement unit 20 (phase difference detection unit), power supply A frequency measurement unit 21, a phase angle calculation unit 22, an A/D conversion unit 23, an effective value calculation unit 24, an A/D conversion unit 25, an effective value calculation unit 26, a leakage current component calculation unit 27, resistance value calculator 28, determination unit 29, blocking unit 30, threshold value setting unit 31, control unit 32, LED 33 (notification unit), buzzer 34 (notification unit), ground height setting unit 35 , temperature sensor 36 (temperature detection unit), humidity sensor 37 (humidity detection unit), clock 38 (use time detection unit), liquid crystal monitor 39 (display unit), external LED 111 (external notification unit), external It has a liquid crystal monitor 112 (external display section) and a fan 121 (ventilation section).

<CT sensor part>
The CT sensor unit 10 is a part that clamps the entire electric line A to be measured and detects the leakage current I flowing through the electric line A to be measured. Specifically, the CT sensor unit 10 detects magnetism caused by leakage current components flowing in the electric line A to be measured, and generates current from the detected magnetism. The CT sensor unit 10 supplies the generated current as a leakage current I to the amplifier unit 11 .

The leakage current I generated by the CT sensor unit 10 includes a leakage current component Igc caused by the ground capacitance and a leakage current component Igr caused by the ground insulation resistance directly related to the insulation resistance. . In addition, the leakage current component Igc increases in capacity not only with the length of the cable under test A, but also with harmonic distortion current caused by inverters and noise filters used in electrical equipment. increase.

<Amplifier>
The amplifying section 11 is a section that converts the leakage current I from the CT sensor section 10 into a voltage and amplifies the converted voltage (converted voltage V1) to a predetermined level. For example, when the leakage current I from the CT sensor section 10 is 0 mA to 10 mA, the amplification section 11 amplifies in two stages. Further, when the leakage current I from the CT sensor unit 10 is 10 mA to 300 mA, the amplification unit 11 amplifies in one stage. Then, the amplification unit 11 supplies the converted voltage V1 after amplification to the LPF 12 .

<LPF>
The LPF 12 is a filter that removes harmonic components from the converted voltage V1 from the amplifier 11 . The LPF 12 then supplies the converted voltage V<b>1 from which the harmonic components have been removed to the full-wave rectifying section 13 and the comparing section 18 .

<Full-wave rectifier>
The full-wave rectifier 13 is a part that rectifies the post-conversion voltage V1 from the LPF 12 . Then, the full-wave rectifier 13 supplies the post-conversion voltage V<b>1 after rectification to the A/D converter 23 .

<Voltage detector>
The voltage detection unit 14 is a part that detects the voltage V2 from the voltage line of the electric line A to be measured by connecting a voltage probe to the electric line A to be measured. When the electric system of the electric line A to be measured is a three-phase three-wire system (a system consisting of delta connections), the voltage detection unit 14 detects the voltage between the R phase and the T phase other than the S phase (ground). If the electric system of the electric line A to be measured is a three-phase four-wire system (a system consisting of star connection), the voltage detection unit 14 detects the voltage between the phases other than the S phase (ground line). Furthermore, when the electric system of the electric line A to be measured is a single-phase two-wire system, the voltage detection section 14 detects the voltage between the N phase and the L phase.

Then, the voltage detection section 14 obtains a reference point from the voltage V2 detected from the wire line A to be measured, and supplies the voltage V2 to the transformation section 15 . For example, the voltage detection unit 14 uses the zero-crossing point of the voltage V2 detected from the wire line A to be measured as a reference point.

<Transformer part>
The transformation unit 15 transforms the voltage V2 detected by the voltage detection unit 14 to a predetermined transformation ratio. That is, the transformation unit 15 transforms the supplied voltage V2 to a predetermined voltage value, and supplies the transformed voltage V to the LPF 16 . The transformation unit 15 transforms the voltage so that the voltage ratio is 20:1, for example.

<LPF>
The LPF 16 is a portion that removes harmonic components from the voltage V2 that has been transformed to a predetermined voltage value by the transformer 15 . The LPF 16 then supplies the voltage V<b>2 from which the harmonic component has been removed to the full-wave rectifying section 17 , the comparing section 18 and the power supply frequency measuring section 21 .

<Full-wave rectifier>
The full-wave rectifier 17 is a part that rectifies the voltage V2 from the LPF 16 . Then, the full-wave rectifier 17 supplies the rectified voltage V2 to the A/D converter 25 .

<Comparison part>
The comparison section 18 is a section that compares the signal waveform S1 of the converted voltage V1 from the LPF 12 and the signal waveform S2 of the voltage V2 from the LPF 16 . That is, the comparison unit 18 takes the 0V cross point of the converted voltage V1 supplied from the LPF 12, performs square wave conversion, and supplies the signal after square wave conversion to the calculation unit 19. FIG. The comparison unit 18 takes the 0V cross point of the voltage V2 supplied from the LPF 16, performs square wave conversion, and supplies the square wave-converted signal to the calculation unit 19. FIG.

<Calculation part>
The calculator 19 is a part that performs a predetermined calculation based on the result of comparison by the comparator 18 . That is, the computing section 19 performs a predetermined computation based on the signal supplied from the comparing section 18 and supplies the signal after the computation to the phase pulse width measuring section 20 . For example, the calculation unit 19 is composed of an EXOR (exclusive OR) circuit, and performs an EXOR calculation on the two square-wave-converted signals supplied from the comparison unit 18 .

<Phase pulse width measurement part>
The phase pulse width measurement section 20 is a section that measures the phase pulse width (phase difference) between the converted voltage V1 and the voltage V2 based on the calculation result of the calculation section 19 .

Specifically, when the electric line A (power supply) to be measured is a single-phase type, as shown in FIG. becomes. Therefore, the phase difference between the leakage current component Igr and the leakage current component Igc is 90° (1/4 cycle). When the electric line A (power supply) to be measured is a three-phase type, the phase angle θ of the leakage current component Igr is 60° and the phase angle θ of the leakage current component Igc is 0°, as shown in FIG. 2B. Therefore, the phase difference between the leakage current component Igr and the leakage current component Igc is 60° (1/6 cycle). Therefore, the phase pulse width measuring unit 20 measures only those with a phase pulse width of 1/4 or less of one cycle so that it can be used when the electric line A (power supply) under test is single-phase or three-phase. and

Then, the phase pulse width measurement unit 20 outputs a phase pulse width of 1/4 or less of one cycle calculated based on the calculation result supplied from the calculation unit 19 to the phase angle calculation unit 22 . When the power supply frequency is 60 Hz, one cycle is 16.6 ms, so the phase pulse width is 4.15 ms or less. Also, when the power supply frequency is 50 Hz, one cycle is 20 ms, so it is 5 ms or less.

<Power frequency measurement unit>
The power frequency measuring unit 21 is a part that measures the power frequency generated in the voltage line of the electric line A to be measured based on the voltage V2 signal from the LPF 16 .

That is, the power frequency measurement unit 21 measures the power frequency based on the voltage V2 supplied from the LPF 16 and supplies the measurement result to the phase angle calculation unit 22 . If the electric line A to be measured is a commercial power source, the measurement result of the power frequency measuring section 21 is 50 Hz or 60 Hz. In addition, the power supply frequency measurement unit 21 may be configured to determine either 50 Hz or 60 Hz based on the voltage V2 supplied from the LPF 16 .

<Phase angle calculator>
The phase angle calculation unit 22 calculates the phase angle of the leakage current I flowing through the electric line A to be measured based on the phase pulse width from the phase pulse width measurement unit 20 and the power supply frequency from the power supply frequency measurement unit 21. part.

That is, the phase angle calculator 22 calculates the wire to be measured using the following equation (1) based on the phase pulse width W supplied from the phase pulse width measurement unit 20 and the power supply frequency F supplied from the power supply frequency measurement unit 21. A phase angle θ of the leakage current I flowing in the path A is calculated.
θ=360×W×F (1)

Then, the phase angle calculator 22 supplies the calculated phase angle θ to the leakage current component calculator 27 .

<A/D converter>
The A/D converter 23 is a part that converts the post-conversion voltage V1 after rectification from the full-wave rectifier 13 into a digital signal. Then, the A/D converter 23 supplies the converted digital signal to the effective value calculator 24 .

<Effective value calculator>
The effective value calculator 24 is a part that calculates the effective value I0 of the converted voltage V1 by the following equation (2) based on the converted voltage V1 converted into a digital signal from the A/D converter 23. . The signal supplied to the effective value calculator 24 is based on the converted voltage V1 obtained by converting the leakage current I flowing in the wire line A to be measured into a voltage, so it is referred to as I0 for convenience.
I0=I×(π/2)/√2 (2)

The effective value calculator 24 then supplies the calculated effective value I0 to the leakage current component calculator 27 .

<A/D converter>
The A/D converter 25 is a part that converts the rectified voltage V2 from the full-wave rectifier 17 into a digital signal. Then, the A/D converter 25 supplies the converted digital signal to the effective value calculator 26 .

<Effective value calculator>
The effective value calculator 26 is a part that calculates the effective value V0 of the voltage V2 by the following equation (3) based on the voltage V2 converted into the digital signal from the A/D converter 25 .
V0=V×(π/2)√2 (3)

The effective value calculator 26 then supplies the calculated effective value V0 to the resistance value calculator 28 .

<Leakage current component calculator>
The leakage current component calculation unit 27 calculates the effective value I0 (leakage current) of the converted voltage V1 calculated by the effective value calculation unit 24 and the phase angle θ of the leakage current I calculated by the phase angle calculation unit 22. Based on this, the leakage current component Igr resulting from the ground insulation resistance is calculated. Then, the leakage current component calculation unit 27 supplies the calculated leakage current component Igr to the determination unit 29 and the resistance value calculation unit 28 .

Here, when the electric line A (power source) to be measured is of a single-phase type, the leakage current component calculator 27 calculates the leakage current component Igr by the following equation (4). When the electric line A (power supply) to be measured is of a three-phase type, the leakage current component calculator 27 calculates the leakage current component Igr by the following equation (5).
Igr=I0×cos θ (4)
Igr=(I0×sin θ)/cos30° (5)

The leakage current component calculator 27 determines whether the electric line A (power source) under test is a single-phase power source or a three-phase power source according to the selection state of a rotary switch (not shown).

<Resistance value calculator>
The resistance value calculator 28 calculates Gr using the following equation (6) based on the effective value V0 supplied from the effective value calculator 26 and the leakage current component Igr supplied from the leakage current component calculator 27. .
Gr=V0/Igr (6)

<Determination part>
The judging section 29 is a part for judging the leakage state of the electric line A to be measured. The processing (operation) of the determination unit 29 will be described later in detail.

<Breaking part>
The breaker 30 is a part that cuts off the wire line A under test according to the break signal from the judgment unit 29 when the determination unit 29 determines that the wire line A under test is leaking.
In addition, the breaking unit 30 conforms to an existing earth leakage breaker, and the breaking speed is about 2 cycles (0.04 seconds at 50 Hz) to 5 cycles (0.1 seconds at 50 Hz). . The breaker 30 is configured by, for example, a tripping coil TC.

<Threshold setting part>
The threshold setting unit 31 is a part for the user to set the leakage threshold and the first to second leakage risk thresholds based on, for example, the leakage current component Igr. The leakage threshold and the first to second leakage potential thresholds are thresholds for determining the leakage state of the wire line A to be measured by comparing with the current leakage current component Igr. The relationship is "first leakage risk threshold<second leakage risk threshold<leakage risk threshold". Here, a configuration is exemplified in which 6 mA is set as the first leakage risk threshold, 8 mA as the second leakage risk threshold, and 15 mA as the leak threshold as the reference values when the ground level is the reference height (10 m). (See Figure 9). However, the specific values of the leakage threshold and the first to second leakage risk thresholds can be changed freely, and the number of leakage risk thresholds can also be changed freely. Here, as will be described later, a configuration is exemplified in which the determination unit 29 calculates and corrects the leakage threshold or the like based on the map of FIG. 9 or the like.

The leakage threshold is set to a value at which it is determined that the cable under test A is currently leaking when the leakage current component Igr is equal to or greater than the leakage threshold.

When the leakage current component Igr is equal to or greater than the first leakage threshold to the second leakage threshold, it is determined that there is a risk of leakage from the electric line A to be measured. set to the value "First leakage risk threshold < Second leakage risk threshold", and by comparing the leakage current component Igr with the first leakage risk threshold and the second leakage risk threshold in order, the risk of leakage from the cable line A to be measured is determined. is determined step by step in two steps.

That is, the leakage current component Igr gradually increases, and by stepwise determination as to whether or not it is equal to or greater than the first leakage threshold and the second leakage threshold, the risk of leakage in the wire line A to be measured can be determined in two stages. It is judged step by step. As the leakage current component Igr gradually increases, the risk of leakage from the wire line A to be measured increases.

<Control part>
The control unit 32 is a part that controls the extinguishment/lighting/blinking of the LED 33 and the external LED 111 and the output color in accordance with the leakage state of the electric line A to be measured. Also, the control section 32 is a section that controls ON/OFF of the buzzer 34 corresponding to the leakage state of the electric line A to be measured.

Further, the control unit 32 is a part that outputs the current leakage current component Igr and the corrected first and second leakage potential threshold values to the liquid crystal monitor 39 and the external liquid crystal monitor 112 for display. Also, the control unit 32 is a part that controls ON/OFF of the fan 121 according to the leakage state of the electric line A to be measured.

<LED>
The LED 33 is a part that notifies the outside of the leakage state/probable leakage state of the wire line A to be measured by lighting/blinking. That is, the LED 33 is a notification unit that notifies the outside of a lighting/blinking/extinction signal (leakage signal/leakage risk signal) corresponding to the leakage state/leakage risk state of the electric line A to be measured.

Here, the LED 33 is configured to turn on/blink in green, yellow, and red, or turn off (OFF) in accordance with a signal from the control unit 32 . Specifically, when the leakage current component Igr is less than a first leakage threshold (for example, 6 mA) (Igr<first leakage threshold), the LED 33 is lit in green. When the leakage current component Igr is greater than or equal to the first leakage threshold and less than a second leakage threshold (e.g., 8 mA) (first leakage threshold ≤ Igr < second leakage threshold), the LED 33 is lit yellow. ing. When the leakage current component Igr is greater than or equal to the second leakage threshold and less than the leakage threshold (for example, 15 mA) (second leakage threshold ≦Igr<leakage threshold), the LED 33 is lit in red. When the leakage current component Igr is equal to or greater than the leakage threshold (leakage threshold≦Igr), the LED 33 is turned off (OFF).

<Buzzer>
The buzzer 34 is a part that outputs a buzzer sound (leakage signal/probable leakage signal) to inform the outside of the leakage state/probable leakage state of the cable line A to be measured. That is, the buzzer 34 is a notification unit that notifies the outside of a buzzer sound (leakage signal/leakage risk signal) corresponding to the leakage state/leakage risk state of the electric line A to be measured.

Specifically, when the leakage current component Igr is less than the second leakage threshold (Igr<second leakage threshold), the buzzer 34 is turned off. When the leakage current component Igr is greater than or equal to the second leakage threshold and less than the leakage threshold (second leakage threshold ≦Igr<leakage threshold), the buzzer 34 is turned on.

<Ground height setting part>
The ground height setting section 35 is a part for the user to set the ground height (m). The height above the ground is the height (elevation) from the ground where the cable line A to be measured is installed. The ground height setting unit 35 outputs the set ground height to the determination unit 29 .

<Temperature sensor>
The temperature sensor 36 is a sensor that detects the temperature around the cable line A to be measured. Then, the temperature sensor 36 calculates the temperature difference, which is the difference between the maximum temperature and the minimum temperature, during the immediately preceding predetermined period (for example, one day immediately preceding, one week immediately preceding, one month immediately preceding). It is designed to output to

<Humidity sensor>
The humidity sensor 37 is a sensor that detects the humidity (relative humidity) around the cable line A to be measured. The humidity sensor 37 outputs the detected humidity to the determination section 29 .

<Clock>
A clock 38 is a clock for detecting the cumulative use (service) time of the cable line A to be measured from the start of use. Then, the clock 38 outputs the usage time to the determination section 29 .

<LCD monitor>
The liquid crystal monitor 39 is a part that displays the leakage current component Igr, the first leakage risk threshold, the second leakage risk threshold, and the leakage risk threshold input from the control unit 32 .

<External LED>
Like the LED 33, the external LED 111 is a part that notifies the outside of the leakage state/probable leakage state of the wire line A to be measured by lighting/blinking. In addition, the external LED 111 is also connected to another leakage current interrupting device 1, and based on the signal from the other leakage current interrupting device 1, the leakage state/probable leakage state of the other electric line A to be measured is output to the outside. This is the notification part. The external LED 111 is installed, for example, on a distribution board or a monitoring board of the leakage current interrupting device 1 .

That is, the external LED 111 lights/blinks based on the signal state from each leakage current interrupting device 1 (control unit 32) to inform the outside of the leakage state/probable leakage state of each electric line A to be measured. part. As a result, the user can centrally monitor the leakage state/probable leakage state of a plurality of electric lines A to be measured via the external LED 111 .

<External LCD monitor>
Like the liquid crystal monitor 39, the external liquid crystal monitor 112 is a portion that displays the leakage current component Igr, the first leakage risk threshold, the second leakage risk threshold, and the leakage threshold input from the control unit 32. FIG. The external liquid crystal monitor 112 is also connected to another leakage current interrupting device 1, and displays the leakage current component Igr from the other control unit 32, the first leakage risk threshold, the second leakage risk threshold, and the leakage threshold. part. The external liquid crystal monitor 112 is installed, for example, on the distribution board or monitoring board of the leakage current interrupting device 1 .

That is, the external liquid crystal monitor 112 is a portion that individually displays the leakage current component Igr from each leakage current interrupting device 1 (each control unit 32), the first leakage risk threshold, the second leakage risk threshold, and the leakage threshold. . As a result, the user can centrally monitor the leak state/probable leak state of a plurality of electric lines A to be measured via the external liquid crystal monitor 112 .

<Fan>
The fan 121 is an electric fan arranged around the cable line A to be measured, and is a blower that ventilates the circumference of the cable line A to be measured by being driven (ON). Here, when the fan 121 is driven, the area around the wire line A to be measured is ventilated, and the humidity and temperature around the wire line A to be measured are lowered.

<<Measurement Principle of Leakage Current Breaker - Waveform>>
Next, the measurement principle of the leakage current interrupting device will be described.
Here, the case where the power source of the electric line A to be measured is three-phase will be described, but the same applies to the case where the power source is single-phase.

The CT sensor unit 10 clamps the electric line A to be measured, and detects waveforms between the R phase and the S phase, between the S phase and the T phase, and between the T phase and the R phase, which phases differ by 120° as shown in FIG. 3A. . Although each waveform is shown in FIG. 3A for convenience, the waveform detected by the CT sensor unit 10 is a composite waveform. A composite waveform detected by the CT sensor unit 10 is input to the computing unit 19 via the amplifying unit 11 , the LPF 12 and the comparing unit 18 .

The voltage detection unit 14 connects voltage probes to the R phase and the T phase, detects the voltage between the R phase and the T phase, and inverts the detected voltage as shown in FIG. 3B. The voltage detection unit 14 determines a point at which the detected voltage crosses 0 at a predetermined location as a reference point a. The voltage V<b>2 with the reference point a determined in this way is input to the calculation unit 19 via the transformation unit 15 , the LPF 16 and the comparison unit 18 .

For example, only the leakage current component Igr (hereinafter referred to as "R phase Igr") occurs in the R phase of the electric line A to be measured, and only the leakage current component Igr (hereinafter referred to as "T phase Igr") occurs in the T phase. occurs, the R-phase Igr has a phase difference of 120° from the reference point a, and the T-phase Igr has a phase difference of 60° from the reference point a, as shown in FIG. 3C.

In addition, only the leakage current component Igc (hereinafter referred to as "R phase Igc") is generated in the R phase of the electric line A to be measured, and only the leakage current component Igc (hereinafter referred to as "T phase Igc") is generated in the T phase. is generated, the phase difference from the reference point a of the composite waveform of the R-phase Igc and the T-phase Igc is 180° (0°), as shown in FIG. 3D.

Furthermore, when the leakage current component Igr and the leakage current component Igc are generated in the R phase of the electric line A to be measured, and the leakage current component Igr and the leakage current component Igc are generated in the T phase, FIG. as shown.

<<Measurement Principle of Leakage Current Breaker - Vector Diagram>>
Also, if the above description is represented by a vector, it will be as follows. Since the line A to be measured is a three-phase type, it becomes as shown in FIG. 4A. Then, when the voltage between the R phase and the T phase is detected by the voltage detection unit 14 and the reference point a is obtained from the detected voltage, a single-phase vector diagram is obtained as shown in FIG. 4B. As described above, the phase difference between the R-phase Igr and the reference point a is 60°, and the phase difference between the T-phase Igr and the reference point a is 120°.

In the case of the single-phase type, as already described with reference to FIG. 2A, the phase difference between the leakage current component Igr and the leakage current component Igc is 90°. Igc can be obtained, and T-phase Igc can be obtained at a position rotated by 90° from T-phase Igr. Furthermore, a composite vector Igc of the R-phase Igc and the T-phase Igc can be obtained at a position 180° (0°) from the reference point a (FIG. 4C).

Therefore, for example, when only the R-phase Igr is generated in the electric line A to be measured, the combined vector of the R-phase Igr and Igc, that is, the leakage current I0 flowing in the electric line A to be measured is shown in FIG. can be expressed as From FIG. 4D, the above-described formula (5) can be derived as the formula for calculating the R-phase Igr. The phase difference θ of the leakage current I0 changes depending on the magnitudes of the R phases Igr and Igc, and the range of change is 60° to 180° from the reference point a.

Further, for example, when only the T-phase Igr is generated in the electric line A to be measured, the combined vector of the T-phases Igr and Igc, that is, the leakage current I0 flowing in the electric line A to be measured is shown in FIG. can be expressed as From FIG. 4E, the above-described formula (5) can be derived as the formula for calculating the T-phase Igr. The phase difference θ of the leakage current I0 varies depending on the magnitudes of the T-phases Igr and Igc, and the range of variation is 120° to 180°.

<<First measurement example of leakage current interrupter>>
Next, Table 1 shows a first measurement example in which leakage current components were actually measured from the electric line A to be measured by the leakage current interrupting device 1 according to this embodiment. Table 1 shows the power panel of the rooftop power receiving and distributing cubicle (high voltage power receiving equipment) (power frequency: 50 Hz, voltage: 200 V, type of low voltage circuit to be measured: three-phase three-wire system, 150 kvA, room temperature: 41 ° C, humidity: 43 %) was measured.

In addition, in the measurement example, 20 kΩ was grounded to the R phase as a pseudo insulation resistance from 6 minutes to 9 minutes (3 minutes) from the start of measurement, and from 9 minutes to 11 minutes (2 minutes) from the start of measurement. ), ground 20 kΩ to the T phase as a pseudo insulation resistance, remove the pseudo insulation resistance (ground release) from 11 minutes to 12 minutes after the start of measurement (1 minute), and from 12 minutes after the start of measurement to 13 Before the minute (1 minute) has elapsed, ground 10 kΩ to the R phase as a pseudo insulation resistance, and from 13 minutes to 15 minutes (2 minutes) after the start of measurement, ground 10 kΩ to the T phase as a pseudo insulation resistance and measure. After 15 minutes from the start, the dummy insulation resistance was removed.
For example, when a resistor of 20 kΩ is grounded to the R phase as a pseudo insulation resistance, theoretically, the current of the pseudo insulation resistance component is
Igr=V/R=200/(20*103)=10mA
current is added to the line under test.

As shown in Table 1, the leakage current interrupting device 1 detected a leakage current component Igr of 12.3 mA when a 20 kΩ resistor was grounded to the R phase as a pseudo insulation resistance after 6 minutes. Since the leakage current component Igr is 2mA when the pseudo insulation resistance is not grounded (before 6 minutes from the start of measurement, before 11 to 12 minutes from the start of measurement, and after 15 minutes from the start of measurement), If 2 mA is subtracted from the leakage current component Igr after grounding the pseudo-resistance of 20 kΩ in the R phase, it becomes 10.3 mA. Therefore, the leakage current interrupting device 1 according to this embodiment was able to measure a change of 10.3 mA. This value substantially matches the theoretical value (10 mA) described above.

Also, when a pseudo insulation resistance of 20 kΩ is grounded to the R phase, the combined resistance value with the resistance value before grounding (Gr ≈ 105.46 kΩ (the average value of Gr from the start of measurement until 6 minutes before the elapse of 6 minutes)) is
Gr=(20×103×105.46×103)/(20×103+105.46×103)≈16.3 kΩ
becomes. As shown in Table 1, the leakage current interrupter 1 exhibits a resistance Gr of 17.2 kΩ after 6 minutes from the start of measurement, which substantially agrees with the theoretical value (16.3 kΩ) described above.

Also, when a 20 kΩ resistor is grounded to the T-phase as a pseudo insulation resistance, the current of the pseudo insulation resistance component theoretically increases by 10 mA as described above. In the leakage current interrupter 1, as shown in Table 1, the leakage current component Igr detected between 9 minutes and 11 minutes after the start of measurement is approximately 12.4 mA, and 2 mA is subtracted from this value. , it becomes 10.4 mA, which almost matches the theoretical value (10 mA).

Further, the combined resistance value Gr when the pseudo insulation resistance of 20 kΩ is grounded to the T phase is theoretically 16.3 kΩ as described above, and the measured value is 17.4 kΩ, which is almost the theoretical value. is consistent with

In addition, as shown in Table 1, the leakage current components Igr and Gr of the leakage current interrupting device 1 when 10 kΩ is grounded to the R phase or T phase as a pseudo insulation resistance are substantially the same as the theoretical values and the actually measured values.

Furthermore, when the leakage current interrupting device 1 releases the grounded state of the pseudo insulation resistance after 11 minutes to 12 minutes and 15 minutes after the start of measurement, the values of the leakage current components Igr, I0 and Gr are grounded. It returned to the previous state (1 to 5 minutes after the start of measurement).

<<Second measurement example of leakage current interrupter>>
Next, Table 2 shows a second measurement example in which the leakage current component was actually measured from the electric line to be measured by the leakage current interrupting device 1 according to this embodiment. Table 2 is for the power panel of a power receiving and distributing cubicle (high voltage power receiving equipment) (power frequency: 50 Hz, voltage: 200 V, type of low voltage circuit to be measured: three-phase three-wire system, 150 kvA). .

In addition, in the measurement example, 0.22 μF was grounded to the R phase and T phase as a pseudo capacitance from 1 minute to 4 minutes (3 minutes) from the start of measurement, and from 3 minutes to 4 minutes after the start of measurement. 20 kΩ was grounded to the T-phase as a pseudo insulation resistance before minutes (1 minute) passed, and after 4 minutes from the start of the measurement, the pseudo capacitance and the pseudo insulation resistance were removed. Therefore, from 3 minutes to 4 minutes after the start of measurement, the pseudo capacitance was grounded to the R phase and the T phase, and the pseudo insulation resistance was grounded to the T phase.

For example, when a capacitance of 0.22 μF is grounded to the R phase and T phase as pseudo capacitance, the capacitive reactance X is
X=1/2πfC=1/(2π×50×(0.22×10−6+0.22×10−6))≈7.23×103
becomes.

Therefore, in the line under test,
I=V/X=200/7.23×103≈27.6mA
current is added and flows.

Further, when a resistance of 20 kΩ is grounded to the T phase as an insulation resistance, theoretically, the current of the pseudo insulation resistance component is
Igr=V/R=200/(20*103)=10mA
current is added to the line under test.

As shown in Table 2, the leakage current interrupting device 1, when 0.22 μF of pseudo capacitance is grounded in the R phase and the T phase when one minute has elapsed from the start of measurement, A leakage current component Igr of 7.8 mA was detected, and I0 of 100.8 mA was detected. Note that I0 is a combined current of the leakage current component Igr caused by the insulation resistance and the leakage current component Igc caused by the capacitance as described above.

As shown in Table 2, the leakage current component Igr when the pseudo-capacitance is not grounded is 7.6 mA (leakage current component Igr one minute before the start of measurement). When the pseudo-capacitance is grounded at , there is almost no change in the leakage current component Igr.

On the other hand, I0 when the pseudo-capacitance is not grounded is 75.9 mA (I0 before 1 minute from the start of measurement). Subtracting I0 (75.9 mA) before pseudo-capacitance grounding from I0 (100.8 mA) after pseudo-capacitance grounding gives 24.9 mA, which is the added leakage current component Igc. This added leakage current component Igc is almost equal to the theoretical value (27.6 mA).

In addition, as shown in Table 2, the leakage current interrupter 1, when the pseudo capacitance is grounded to the R phase and the T phase, and the pseudo insulation resistance is grounded to the T phase (3 minutes from the start of measurement) 21.0 mA of leakage current component Igr was detected, and 107.0 mA of I0 was detected.

Subtracting the leakage current component Igr (8 mA (leakage current component Igr after 3 minutes from the start of measurement)) before grounding the insulation resistance from the leakage current component Igr (21 mA) after the insulation resistance is grounded to the T phase, , 13 mA, which is almost equal to the theoretical value (10 mA).

≪Operation example of comparison part and calculation part≫
Next, the operation of the comparing section 18 and the calculating section 19 when 10 kΩ is grounded as a pseudo insulation resistance to the R phase will be described with reference to FIGS. 5 to 7. FIG.

As shown in FIG. 5, the comparator 18 receives the converted voltage V1 from the LPF 12 and the voltage V2 from the LPF 16 . The phase difference between the converted voltage V1 and the voltage V2 is 120°. As shown in FIG. 6A, the comparator 18 square-wave-converts the converted voltage V1 input from the LPF 12 and outputs the converted signal to the calculator 19 . In addition, as shown in FIG. 6B, the comparison unit 18 square-wave-converts the voltage V2 input from the LPF 16 and outputs the converted signal to the calculation unit 19 .

As shown in FIG. 7, the calculation unit 19 performs an EXOR calculation based on the square wave signal of the converted voltage V2 and the square wave signal of the voltage V2. The calculation unit 19 obtains a phase pulse width of 1/4 or less of one cycle based on the signal after the EXOR calculation, and outputs the obtained phase pulse width to the phase angle calculation unit 22 .

≪Operation of leakage current interrupter≫
Next, operation of the leakage current interrupting device 1 will be described with reference to FIG. In the initial state, the LED 33 and the external LED 111 are lit in green, the buzzer 34 is stopped, and the fan 121 is stopped.

<Calculation and Correction of First Leakage Risk Threshold>
In step S101, the determination unit 29 calculates and corrects the first leakage risk threshold.

<Calculation (correction) of first leakage risk threshold based on ground height>
Specifically, the determination unit 29 determines the first leakage threshold as a determination criterion based on the ground height input to the ground height setting unit 35 and the map (graph) of the first leakage risk threshold shown in FIG. Calculate the risk threshold. The map of the first leakage risk threshold, the map of the second leakage risk threshold, and the map of the leakage threshold, which will be described later, are obtained by preliminary tests, simulations, or the like, and are stored in the determination unit 29 .

As shown in FIG. 9, the first leakage risk threshold value linearly decreases as the height above the ground decreases. That is, as the ground height becomes smaller, the first leakage risk threshold is corrected to be smaller. Here, when the height above the ground becomes small, the temperature of the electric line A to be measured tends to become low and dew condensation tends to occur, so that leakage tends to occur. Therefore, by decreasing the first leakage risk threshold, which is a criterion for determination, as the ground height becomes smaller, it becomes easier to accurately determine whether or not there is a risk of leakage. Here, the first leakage risk threshold is set to 6 mA at the reference ground level (10 m).

<Correction based on usage time>
Next, the determination unit 29 calculates a correction coefficient related to the usage time based on the usage time from the clock 38 and the correction coefficient map (graph) shown in FIG. The map of correction coefficients is obtained by preliminary tests, simulations, etc., and is stored in the determination unit 29 .

As shown in FIG. 10, the correction coefficient related to usage time has a relationship of linearly decreasing as the usage time increases. Here, when the usage time is 0, the correction coefficient is set to 1. Then, the determination unit 29 multiplies the first leakage risk threshold calculated based on the ground height by a correction coefficient related to the usage time to correct the first leakage risk threshold. That is, as the usage time becomes longer, the first leakage risk threshold is corrected to become smaller. Here, as the usage time becomes longer, the deterioration of the wire line A to be measured (for example, the deterioration of the insulation coating) progresses, and leakage becomes more likely. Therefore, it becomes easier to accurately determine whether or not there is a risk of leakage by decreasing the first leakage risk threshold, which serves as a determination criterion, as the usage time increases.

<Correction based on humidity>
Next, the determination unit 29 calculates a correction coefficient related to humidity based on the humidity from the humidity sensor 37 and the correction coefficient map (graph) shown in FIG. 11 . The map of correction coefficients is obtained by preliminary tests, simulations, etc., and is stored in the determination unit 29 .

As shown in FIG. 11, the correction coefficient related to humidity has a relationship of linearly decreasing as the humidity increases. Here, the correction coefficient is set to 1 at a humidity of 50%. Then, the determination unit 29 multiplies the first leakage risk threshold value calculated based on the ground height by a correction coefficient related to humidity to correct the first leakage risk threshold value. That is, as the humidity increases, the first leakage risk threshold value is corrected to decrease. Here, when the humidity is high, dew condensation is likely to occur around the wire line A to be measured, and leakage is likely to occur. Therefore, by decreasing the first leakage risk threshold, which is a criterion for determination, as the humidity increases, it becomes easier to accurately determine whether or not there is a risk of leakage.

<Correction based on temperature difference>
Next, the determination unit 29 calculates a correction coefficient related to the temperature difference based on the temperature difference (° C.) from the temperature sensor 36 and the correction coefficient map (graph) shown in FIG. 12 . The map of correction coefficients is obtained by preliminary tests, simulations, etc., and is stored in the determination unit 29 .

As shown in FIG. 12, the correction coefficient related to the temperature difference has a relationship of linearly decreasing as the temperature difference increases. Here, the correction coefficient is set to 1 when the temperature difference is 0. Then, the determination unit 29 multiplies the first leakage risk threshold calculated based on the ground height by a correction coefficient related to the temperature difference to correct the first leakage risk threshold. That is, as the temperature difference increases, the first leakage risk threshold is corrected to decrease. Here, when the temperature difference increases, condensation tends to occur around the wire line A to be measured, and leakage tends to occur. Therefore, as the temperature difference increases, the first leakage risk threshold, which serves as a criterion for determination, is decreased, making it easier to accurately determine whether or not there is a risk of leakage.

<Summary>
That is, the determination unit 29 sets the first leakage risk threshold value (see FIG. 9) based on the ground height, the correction coefficient related to the usage time (see FIG. 10), the correction coefficient related to the humidity (see FIG. 11), and the temperature A correction coefficient (see FIG. 12) relating to the difference is multiplied to correct the first leakage risk threshold, and the corrected first leakage risk threshold is calculated. Note that the control unit 32 outputs the corrected first leakage risk threshold to the liquid crystal monitor 39 and the external liquid crystal monitor 112 for display.

In step S102, the determination unit 29 determines whether or not the leakage current component Igr is greater than or equal to the corrected first leakage risk threshold. The control unit 32 outputs the leakage current component Igr to the liquid crystal monitor 39 and the external liquid crystal monitor 112 for display. When it is determined that the leakage current component Igr is equal to or greater than the corrected first leakage risk threshold (S102, Yes), the processing of the leakage current interrupting device 1 proceeds to step S103. When it is determined that the leakage current component Igr is not equal to or greater than the corrected first leakage potential threshold (S102, No), the processing of the leakage current interrupting device 1 proceeds to step S101.

In step S103, the controller 32 lights the LED 33 and the external LED 111 in yellow. In addition, the control unit 32 turns on (drives) the fan 121 to ventilate the circumference of the wire line A to be measured. As a result, the humidity around the wire line A to be measured is lowered, and dew condensation is less likely to occur, so leakage is less likely to occur.

In step S104, the determination unit 29 determines whether or not the leakage current component Igr is smaller than the corrected first leakage potential threshold. When it is determined that the leakage current component Igr is smaller than the corrected first leakage risk threshold (S104, Yes), the processing of the leakage current interrupting device 1 proceeds to step S105. When it is determined that the leakage current component Igr is not smaller than the corrected first leakage risk threshold (S104, No), the processing of the leakage current interrupting device 1 proceeds to step S106.

In step S105, the controller 32 lights the LED 33 and the external LED 111 in green. Further, the control unit 32 turns off (stops) the fan 121 . Then, the processing of the leakage current interrupting device 1 proceeds to step S101.

<Calculation and Correction of Second Leakage Risk Threshold>
In step S106, the determination unit 29 calculates and corrects the second leakage risk threshold, as in step S101.

<Calculation (correction) of second leakage risk threshold based on ground height>
Specifically, the determination unit 29 sets the second threshold as a determination criterion based on the ground height input to the ground height setting unit 35 and the map (graph) of the second leakage risk threshold shown in FIG. Calculate the leakage risk threshold.

As shown in FIG. 9, the second leakage risk threshold value linearly decreases as the height above the ground decreases. That is, as the ground height becomes smaller, the second leakage risk threshold is corrected to be smaller. Here, the second leakage risk threshold is set to 8 mA at the reference ground level (10 m).

<Correction based on usage time>
Next, the determination unit 29 calculates a correction coefficient related to the usage time based on the usage time from the clock 38 and the correction coefficient map (graph) shown in FIG. Then, the determination unit 29 multiplies the second leakage risk threshold value calculated based on the ground height by a correction coefficient related to the usage time to correct the second leakage risk threshold value.

<Correction based on humidity>
Next, the determination unit 29 calculates a correction coefficient related to humidity based on the humidity from the humidity sensor 37 and the correction coefficient map (graph) shown in FIG. 11 . Then, the determination unit 29 multiplies the second leakage risk threshold calculated based on the ground height by a correction coefficient related to humidity to correct the second leakage risk threshold.

<Correction based on temperature difference>
Next, the determination unit 29 calculates a correction coefficient related to the temperature difference based on the temperature difference (° C.) from the temperature sensor 36 and the correction coefficient map (graph) shown in FIG. 12 . Then, the determination unit 29 multiplies the second leakage risk threshold value calculated based on the ground height by a correction coefficient related to the temperature difference to correct the second leakage risk threshold value.

<Summary>
That is, the determination unit 29 sets the second leakage risk threshold value (see FIG. 9) based on the ground height, the correction coefficient related to the usage time (see FIG. 10), the correction coefficient related to the humidity (see FIG. 11), and the temperature A correction coefficient (see FIG. 12) relating to the difference is multiplied to correct the second leakage risk threshold, and the corrected second leakage risk threshold is calculated. The control unit 32 outputs the corrected second leakage risk threshold to the liquid crystal monitor 39 and the external liquid crystal monitor 112 for display.

In step S107, the determination unit 29 determines whether or not the leakage current component Igr is equal to or greater than the corrected second leakage potential threshold. When it is determined that the leakage current component Igr is equal to or greater than the corrected second leakage risk threshold (S107, Yes), the processing of the leakage current interrupting device 1 proceeds to step S108. When it is determined that the leakage current component Igr is not equal to or greater than the corrected second leakage risk threshold (S107, No), the processing of the leakage current interrupting device 1 proceeds to step S104.

In step S108, the control unit 32 lights the LED 33 and the external LED 111 in red, and turns on the buzzer 34. FIG.

In step S109, the determination unit 29 determines whether or not the leakage current component Igr is smaller than the corrected second leakage risk threshold. When it is determined that the leakage current component Igr is smaller than the corrected second leakage risk threshold (S109, Yes), the processing of the leakage current interrupting device 1 proceeds to step S110. When it is determined that the leakage current component Igr is not smaller than the corrected second leakage risk threshold (S109, No), the processing of the leakage current interrupting device 1 proceeds to step S111.

In step S110, the controller 32 turns off the buzzer . After that, the processing of the leakage current interrupting device 1 proceeds to step S103.

<Calculation and Correction of Leakage Threshold>
In step S111, the determination unit 29 calculates and corrects the leakage threshold value in the same manner as in step S101.

<Calculation (correction) of leakage threshold based on ground height>
Specifically, the determination unit 29 calculates a leakage threshold as a criterion based on the ground height input to the ground height setting unit 35 and the leakage threshold map (graph) shown in FIG. 9 .

As shown in FIG. 9, the leakage threshold value linearly decreases as the ground height decreases. That is, as the height above the ground becomes smaller, the leakage threshold is corrected to become smaller. Here, the leakage threshold is set to 15 mA at the reference ground level (10 m).

<Correction based on usage time>
Next, the determination unit 29 calculates a correction coefficient related to the usage time based on the usage time from the clock 38 and the correction coefficient map (graph) shown in FIG. Then, the determination unit 29 multiplies the leakage threshold calculated based on the ground height by a correction coefficient related to the usage time to correct the leakage threshold.

<Correction based on humidity>
Next, the determination unit 29 calculates a correction coefficient related to humidity based on the humidity from the humidity sensor 37 and the correction coefficient map (graph) shown in FIG. 11 . Then, the determination unit 29 multiplies the leakage threshold calculated based on the ground height by a correction coefficient related to humidity to correct the leakage threshold.

<Correction based on temperature difference>
Next, the determination unit 29 calculates a correction coefficient related to the temperature difference based on the temperature difference (° C.) from the temperature sensor 36 and the correction coefficient map (graph) shown in FIG. 12 . Then, the determination unit 29 multiplies the leakage threshold calculated based on the ground height by a correction coefficient related to the temperature difference to correct the leakage threshold.

<Summary>
That is, the determination unit 29 adds a leakage threshold value (see FIG. 9) based on ground height, a correction coefficient (see FIG. 10) related to usage time, a correction coefficient (see FIG. 11) related to humidity, and a correction coefficient related to temperature difference (see FIG. 11). A correction coefficient (see FIG. 12) is multiplied to correct the leakage threshold, and the corrected leakage threshold is calculated. The control unit 32 outputs the corrected leakage threshold to the liquid crystal monitor 39 and the external liquid crystal monitor 112 for display.

In step S112, the determination unit 29 determines whether or not the leakage current component Igr is greater than or equal to the corrected leakage threshold. When it is determined that the leakage current component Igr is equal to or greater than the corrected leakage threshold (S112, Yes), the processing of the leakage current interrupting device 1 proceeds to step S113. When it is determined that the leakage current component Igr is not equal to or greater than the corrected leakage threshold (S112, No), the processing of the leakage current interrupting device 1 proceeds to step S109.

In step S113, the interrupter 30 electrically interrupts the wire line A to be measured. As a result, the leakage current interrupting device 1 loses power, so that the LED 33 is extinguished (OFF), the buzzer 34 is stopped (OFF), and the fan 121 is stopped (OFF).

After that, the processing of the leakage current interrupting device 1 proceeds to END, and the series of processing ends.

≪Effect of Leakage Current Breaker≫
Effects of the leakage current interrupting device 1 will be described.
If the leakage current component Igr is greater than or equal to the corrected leakage threshold value (e.g., 15 mA or more) (S112, Yes), the determination unit 29 determines that the cable under test A is leaking. Road A is blocked (S113). As a result, electric leakage (leakage) in the electric line A to be measured can be prevented.

If the leakage current component Igr is equal to or higher than the corrected first leakage potential threshold (for example, 6 mA or higher) (S102, Yes), the controller 32 lights the LED 33 and the external LED 111 in yellow (S103). The risk of leakage can be detected before the measurement cable line A is cut off. As a result, it is possible to check whether or not there is leakage before the electric line A to be measured is cut off. That is, for example, when the leakage current component Igr becomes equal to or higher than the corrected first leakage risk threshold value (for example, 6 mA) due to an increase in humidity, and the LED 33 lights up in yellow, the power supply is continued without interrupting the electric line A to be measured. By turning on the fan 121 to dehumidify in this state, the leakage current component Igr can be reduced.

While the LED 33 is lit in yellow (S103), if the leakage current component Igr drops below the corrected first leakage risk threshold (for example, 6 mA) (S104, Yes), the controller 32 turns the LED 33 in green. Since the light is turned on (S105), the initial state (immediately before) of the LED 33 can be restored. While the LED 33 is lit in red (S108), the same applies to the case where the leakage current component Igr drops below the corrected second leakage risk threshold (eg, 8 mA) (S109, Yes).

The judging section 29 compares the leakage current component Igr with the first and second leakage risk thresholds (eg, 6 mA and 8 mA) corresponding to the degree of risk of leakage from the electric line A to be measured (S102, S107). , the risk of leakage can be determined in a plurality of stages. Then, in response to this, the control unit 32 lights the LED 33 and the external LED 111 in yellow (S103) and red (S108), and turns on the buzzer 34 (S108), so that the user has multiple fears of leakage. can be detected step by step.

Since the judging section 29 corrects the first leakage risk threshold, the second leakage risk threshold, and the leakage threshold based on the height above the ground, usage time, humidity, and temperature difference, the leakage state of the cable line A to be measured can be properly determined. I can judge.

The control unit 32 outputs the leakage current component Igr, the corrected first leakage risk threshold, the corrected second leakage risk threshold, and the corrected leakage risk threshold to the liquid crystal monitor 39 and the external liquid crystal monitor 112 for display. A user can easily and reliably monitor the leakage current component Igr and the like.

≪Example of operation of leakage current interrupter≫
Next, an operation example of the leakage current interrupting device 1 will be described with reference to FIG. 13 . Here, in order to simplify the explanation, the ground height is the standard (see FIG. 9), the correction coefficient for usage time is 1 (see FIG. 10), and the correction coefficient for humidity is 1 (see FIG. 10). 11), and the correction coefficient for the temperature difference is 1 (see FIG. 12).

When the leakage current component Igr reaches 6 mA (first leakage risk threshold) (S102, Yes), the LED 33 lights up in yellow (S103). After that, when the leakage current component Igr reaches 8 mA (second leakage potential threshold) (S107, Yes), the LED 33 lights up in red and the buzzer 34 turns on (S108). After that, when the leakage current component Igr reaches 15 mA (leakage threshold value) (S112, Yes), the breaker 30 shuts off (OFF) the wire line A to be measured (S113), and the LED 33 and the buzzer 34 are turned off.

<<Modification>>
Although one embodiment of the present invention has been described above, the present invention is not limited to this, and may be modified as follows, for example.

In the above-described embodiment, the configuration in which two leakage risk thresholds (the first leakage risk threshold to the second leakage risk threshold) are set is exemplified, but in addition, for example, there may be a configuration in which there is only one leakage risk threshold. However, the configuration may be three or more.

In the above-described embodiment, the reporting unit is the LED 33 and the buzzer 34, and the LED 33 lights/blinks/lights out in a plurality of colors in response to the leakage state/probable leakage state of the electric line A to be measured, and the buzzer 34 buzzes. Although the configuration for outputting sound has been exemplified, in addition, for example, the notification unit is a buzzer (alarm device), and the leakage signal/leakage risk signal corresponding to the leakage state/leakage risk state of the cable line A to be measured can be generated by a buzzer sound. There may be some configuration. In this case, the type of buzzer sound, the output interval of the buzzer sound, etc., can be changed according to the leakage state/probable leakage state of the electric line A to be measured.

In the above-described embodiment, the determination unit 29 exemplifies a configuration in which the first leakage risk threshold value is corrected based on four factors: height above ground, usage time, humidity, and temperature difference. , usage time, humidity, and temperature difference. The same applies to the second leakage risk threshold and the leakage threshold.

In the above-described embodiment, the control unit 32 outputs the leakage current component Igr, the corrected first leakage risk threshold, the corrected second leakage risk threshold, and the corrected leakage threshold to the liquid crystal monitor 39 and the external liquid crystal monitor 112. Although the configuration for outputting and displaying has been exemplified, in addition, for example, at least one may be configured for outputting and displaying.

1 leakage current interrupter 10 CT sensor unit (leakage current detection unit)
14 voltage detection unit 20 phase pulse width measurement unit (phase difference detection unit)
21 power supply frequency measurement unit 22 phase angle calculation unit 27 leakage current component calculation unit (earth insulation resistance leakage current component calculation unit)
29 determination unit 30 blocking unit 31 threshold setting unit (leakage threshold setting unit, leakage risk threshold setting unit)
33 LED (notification unit)
34 buzzer (notification part)
35 ground height setting unit 36 temperature sensor (temperature detection unit)
37 humidity sensor (humidity detector)
38 clock (use time detector)
39 LCD monitor (display)
111 external LED (notification unit)
112 External LCD monitor (display)
121 fan (ventilation part)
A Wire line to be measured

Claims (8)

a leakage current detector that detects leakage current flowing through the wire to be measured;
a voltage detection unit that detects the voltage applied to the wire line under test;
a phase difference detection unit for detecting a phase difference between a signal waveform of the leakage current detected by the leakage current detection unit and a signal waveform of the voltage detected by the voltage detection unit;
a power frequency measurement unit that measures the power frequency applied to the wire line under test based on the signal waveform of the voltage detected by the voltage detection unit;
a phase angle calculation unit that calculates the phase angle of the leakage current flowing through the electric line under test based on the phase difference detected by the phase difference detection unit and the power supply frequency measured by the power supply frequency measurement unit;
A ground insulation resistance for calculating a leakage current component Igr caused by the ground insulation resistance included in the leakage current based on the leakage current detected by the leakage current detection unit and the phase angle calculated by the phase angle calculation unit. a leakage current component calculator;
a determination unit that determines a leakage state of the electric line to be measured based on the leakage current component Igr calculated by the ground insulation resistance leakage current component calculation unit;
a breaker for breaking the wire line under measurement when the determination unit determines that the wire line under test is leaking;
a notification unit that notifies the leakage state determined by the determination unit;
a humidity detection unit that detects humidity;
a ventilation unit for ventilating the circumference of the cable under test;
with
The determination unit is
If the leakage current component Igr is equal to or greater than the leakage threshold value for determining that the leakage current component is leaking, it is determined that the cable under test is leaking,
correcting the leakage risk threshold, which is smaller than the leakage threshold and is determined to be likely to leak, so as to decrease as the humidity detected by the humidity detection unit increases;
If the leakage current component Igr is equal to or greater than the corrected leakage risk threshold, it is determined that there is a risk of leakage from the cable under test,
When the determination unit determines that there is a risk of leakage from the electric line under test, the notification unit notifies a leakage fear signal corresponding to the possibility of leakage from the electric line under test , and the ventilation unit start ventilation
A leakage current interrupting device characterized by: When the determination unit determines that the leakage current component Igr has decreased below the leakage risk threshold value while the reporting unit reports the leakage risk signal and the ventilation unit is ventilating , the reporting unit outputs the leakage risk signal. Stop reporting and the ventilator stops ventilation
The leakage current interrupting device according to claim 1 , characterized in that: A usage time detection unit that detects the usage time of the wire line to be measured,
3. The leakage current cut-off device according to claim 2 , wherein the determination unit corrects the leakage risk threshold value so as to decrease as the usage time detected by the usage time detection unit increases. Equipped with a temperature detection unit that detects temperature,
3. The leakage current cut-off device according to claim 2 , wherein the determination unit corrects the leakage potential threshold so as to decrease as the temperature difference in the predetermined time based on the temperature detected by the temperature detection unit increases. . Equipped with a ground height setting unit that sets the ground height from the ground,
3. The leakage current cut-off device according to claim 2 , wherein the determination unit corrects the leakage possibility threshold value so as to decrease as the ground height set in the ground height setting unit decreases. The leakage current interrupting device according to any one of claims 2 to 5 , further comprising a display unit that displays at least one of the leakage current component Igr, the leakage threshold, and the potential leakage threshold. a leakage state determined by the determining unit;
a leakage state determined by a determination unit that constitutes another leakage current interrupting device;
Equipped with an external notification unit that notifies
The leakage current interrupting device according to any one of claims 2 to 5, characterized in that: The judging unit judges the risk of leakage in the electric line under test in a plurality of stages based on a plurality of leakage risk threshold values corresponding to the degree of risk of leakage in the electric line under test,
6. The leakage current interruption according to any one of claims 2 to 5 , wherein the notifying unit notifies a leakage fear signal corresponding to a stage of fear of leakage from the electric line to be measured. Device.

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