JP2018155681A - Ground short discrimination device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a ground short discrimination device capable of discriminating simply and accurately the presence or absence of a short circuit grounding tool connected between an electric grid and a power failure zone.SOLUTION: A ground short discrimination device is a short circuit grounding tool having a short line for shortening a power distribution line and discriminates a removing situation of the short circuit grounding tools which are arranged at one point and the other point, respectively. The ground short discrimination device includes: transmission means for applying an AC voltage at least to one power distribution line at the one point to transmit a current; receiving means for receiving a current flowing through the other one or more power distribution line(s) at the one point; and discrimination means for discriminating a removing situation of the short circuit grounding tool at the other point based on the current received by the receiving means.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a grounding short-circuit determination device that determines the removal status of a short-circuit grounding device connected to a power line power outage section, and in particular, grounding that can reliably determine the removal status of a short-circuiting grounding device while suppressing the influence of the external environment. The present invention relates to a short circuit determination device.

  In high-voltage distribution lines, there is a short-circuit grounding device for grounding the work section to ensure the safety of workers when the work section being worked on is accidentally charged when performing work such as bypass construction. Connected to high-voltage distribution lines. This short-circuit grounding device is a temporarily connected device, and is removed by the operator after the construction.

  However, after construction, the operator may forget to remove the short-circuit grounding device and leave it connected to the distribution line. In such a case, the short-circuit grounding device remains connected to the distribution line. When power transmission is resumed in this condition, ground faults / short-circuit accidents and spillover accidents (power outages of all customers at the same substation feeder) have become serious problems. As a cause of forgetting to remove such a short-circuit grounding device, a major factor is that it depends on an artificial confirmation work such as an operator's visual inspection.

  In order to prevent such forgetting to remove the short-circuit grounding equipment after construction, various measures have been studied.

  For example, there is a method of applying an AC voltage between the ground and detecting a current between the ground. This is because an AC voltage is applied to a grounding wire that grounds a short-circuit grounding device in a contactless manner with a transmitter that generates an AC voltage and a conductor, and an AC voltage is connected to the ground via the grounding wire of the short-circuiting grounding device In this method, a voltage is applied and a current flowing between the ground is detected by a non-contact current sensor and a receiver having a display function.

  However, this method cannot accurately determine the current detected between the ground due to the influence of the capacitance of the pole transformer and the ground capacitance of the distribution line in the power outage section. Furthermore, since the resistance of the ground varies depending on the geology, season, and weather, a threshold cannot be set, and therefore determination using the ground resistance is difficult.

  In addition to this, it is unthinkable to perform a meggering between the wire and the ground by floating the grounding wire of the short-circuiting grounding device from the ground. It is an action that is sometimes carried out, which is against the occupational safety regulations, and is not realistic considering safety aspects.

  In addition, although it is conceivable to measure the ground resistance (see, for example, Patent Documents 1 and 2), it is affected by the capacitance of the pole transformer in the power outage section and the ground capacitance of the distribution line, The ground resistance cannot be measured accurately. In addition, since the earth resistance greatly varies depending on the geology, the threshold value cannot be set, and it becomes difficult to make a desired determination.

For this reason, it is possible to prevent forgetting to remove the short-circuit grounding equipment connected to the distribution line power outage section after construction, ground fault / short-circuit accident due to restarting power transmission while the short-circuit grounding equipment is connected to the distribution line, and Realization of a ground short-circuit discrimination device capable of preventing the occurrence of a spillover accident is desired.

  As such a conventional ground / short-circuit determination device, there is a short-circuit / grounding device that issues an alarm when the user forgets to remove the short-circuit / grounding device after the work is completed. A plurality of power line short-circuit parts having a connection tool that can be attached to and detached from the power line, and a ground part that has a grounding fitting to be attached to and detached from the ground line and that is electrically connected to the power line short-circuit part. There is a short-circuit grounding device characterized by comprising an alarm means comprising a light emitting part or a ringing part, and a power source for supplying electric power to the alarm means (see Patent Document 3).

JP 2001-242206 A JP 2008-39426 A JP 2008-130297 A

  However, the conventional ground / short-circuit determination device includes a short-circuit / grounding device that issues an alarm when the short-circuit / grounding device is forgotten to be removed, as in, for example, Patent Document 3 described above, but the power outage section generally extends over a long distance. Therefore, a large number of alarm means are required, and as a result, the location specified by the alarm becomes unclear, and even if an alarm is issued, it is difficult to specify the corresponding location. Furthermore, when the work is grounded with a short-circuit grounding device other than the short-circuit grounding device, the effect cannot be sufficiently exhibited because there is a portion without an alarm means. Further, there is no method for detecting the presence or absence of a short-circuit grounding device at another point remote from the confirmation point.

  As described above, in the conventional ground / short-circuit determination device, when determining the presence / absence of a plurality of short-circuit / grounding devices in the power outage section, the influence of the ground resistance, between the primary winding and the secondary winding of the pole transformer, and It is limited to those affected by the external environment such as the capacitance between the exterior and the capacitance of the distribution line to the ground.

  The present invention has been made to solve the above-mentioned problems, and provides a ground / short-circuit determination device that can easily and accurately determine the presence / absence of a short-circuit / grounding device connected to a distribution line power outage section. The purpose is to do.

  As a result of diligent research, the present inventor has found a method capable of determining the presence or absence of other short-circuit grounding equipment (other than the confirmation point) without being affected by the grounding resistance and the pole transformer, A new type of excellent ground short-circuit discrimination device that can be reliably identified has been derived.

  That is, the ground / short-circuit determination device disclosed in the present application is a short-circuit grounding device having a short-circuit line that short-circuits the distribution line, and for determining the removal status of the short-circuiting ground devices respectively disposed at one point and another point. In the ground short-circuit determination device, at one point, at least one distribution line, transmitting means for applying an AC voltage to transmit current, and at the one point, one or more other distribution lines Receiving means for receiving the current flowing through the receiving means, and discriminating means for discriminating the removal status of the short-circuit grounding device at the other point based on the current received by the receiving means.

  In this way, at the one point, the transmitting unit applies an AC voltage to transmit current, and based on the current received by the receiving unit, the determining unit is configured to detect the short-circuit grounding device at the other point. Since the removal status is determined, the inductance of the pole transformer winding, the capacitance between the primary and secondary windings and the exterior, and the electrostatic capacitance of the distribution line are not affected by the ground resistance. It is possible to determine the removal status of the short-circuit grounding device at the other point with high accuracy while suppressing the influence of the capacity.

  Further, in the ground / short-circuit determination device disclosed in the present application, the determination unit calculates an impedance from the current received by the reception unit, if necessary, and the short-circuit ground at the other point based on the impedance. This is to determine the removal status of the instrument. As described above, since the determination unit determines whether or not a short-circuit grounding device exists other than the one point based on the impedance calculated from the current received by the reception unit, The removal status of the short-circuit grounding device can be accurately determined without being affected, and the removal status of the short-circuiting grounding device at the other point can be determined with higher accuracy.

  Further, in the ground short-circuit determination device disclosed in the present application, the transmission unit applies an AC voltage of 1 kHz to 30 kHz and transmits current as necessary. Thus, since the frequency of the alternating voltage by the transmitting means is 1 kHz to 30 kHz, the receiving means can receive the current with the influence of the external inductance and the influence of the electrostatic capacity suppressed optimally, The determination means can determine the removal status of the short-circuit grounding device at the other point with higher accuracy.

  Further, in the ground short circuit determination device disclosed in the present application, the transmission unit applies an AC voltage of 1 kHz to 10 kHz as necessary to transmit a current, and the determination unit transmits the short circuit ground at the other point as necessary. When the detachment status of the appliance cannot be determined, the transmission means further includes a determination control unit that performs control to apply an AC voltage of 10 kHz to 30 kHz. As described above, first, even when the discrimination means makes a discrimination with high accuracy by applying an AC voltage having a frequency of 1 kHz to 10 kHz, which makes it easier to detect the change amount (easier to discriminate). Further, it is possible to additionally discriminate by an AC voltage having a frequency of 10 kHz to 30 kHz, and it is possible to more reliably determine the removal status of the short-circuit grounding device at the other point.

  Moreover, in the ground short-circuit determination device disclosed in the present application, the transmission unit applies the AC voltage simultaneously to the plurality of distribution lines and transmits a current as necessary. In this way, since the current is simultaneously transmitted to the plurality of distribution lines, the work load is suppressed and the time is more efficient than when the current is transmitted for each of the distribution lines. The discrimination can be performed accurately.

1 is a configuration diagram of a ground short circuit determination device according to a first embodiment of the present invention. FIG. 1 is a configuration diagram of a ground short circuit determination device according to a first embodiment of the present invention. FIG. Explanatory drawing explaining the current path (arrow a) of the electric current which flows when applying an alternating voltage between the lines of a distribution line from the short circuit line of a short circuit grounding instrument in the earthing short circuit discrimination device concerning a 1st embodiment of the present invention. Indicates. The ground short-circuit discrimination apparatus according to the first embodiment of the present invention shows an equivalent circuit when an AC voltage is applied between the lines of the distribution line. In the ground short circuit discrimination device according to the first embodiment of the present invention, the result of the frequency characteristics of the inductance of the primary windings of a plurality of pole transformers is shown. In the ground short circuit discriminating device according to the first embodiment of the present invention, a comparison result of the impedance conversion value of the inductance of the primary winding of the pole transformer and the measured impedance value of the primary winding of the pole transformer is shown. 1 shows a configuration diagram in which a ground short-circuit determination device according to a first embodiment of the present invention includes a transmitter and a receiver. FIG. The grounding short circuit discrimination device concerning the 1st embodiment of the present invention shows the lineblock diagram comprised from the transmitter, the receiver, and the radio. The block diagram of the earth | ground short-circuit determination apparatus which concerns on the 2nd Embodiment of this invention is shown.

(First embodiment)
A ground short-circuit determination device according to a first embodiment of the present application will be described with reference to the block diagram of FIG.

  As shown in FIG. 1, the ground / short-circuit determination device according to the first embodiment is a short-circuit grounding device 200 having a short-circuit line 201 that short-circuits the distribution line 100, and is disposed at one point and another point, respectively. A grounding short-circuit determination device for determining the removal status of the short-circuit grounding device 200, and transmitting means 1 for transmitting an electric current by applying an alternating voltage to at least one distribution line 100 at this one point. And receiving means 2 for receiving the current flowing through one or more other distribution lines 100 at the one point, and the short-circuit grounding device at the other point based on the current received by the receiving means 2 And a discriminating means 3 for discriminating the removal status of 200.

  The transmission means 1 transmits an electric current by applying an alternating voltage to at least one distribution line 100 at this one point. As shown in FIG. 1, the transmission means 1 can be connected in a non-contact manner by connecting to the short-circuit line 201 using a current transformer (CT) 11. In addition to being connected to the short-circuit line 201, the transmission means 1 can be connected in a non-contact manner by connecting to the distribution line 100 using CT.

  This one point is a point where the last short-circuit grounding device 200 connected in the distribution line power outage section is removed after the distribution line power outage work, and is also referred to as a confirmation point. In addition, this other point is a point other than this confirmation point, and includes a case where it is one place, and also includes a case where there are a plurality of places. 200 is a point where the short-circuit grounding device 200 has been removed after the power distribution line power outage work.

  The frequency of the AC voltage applied by the transmission means 1 is not particularly limited, but is preferably a frequency of 1 kHz to 30 kHz. The reason for this is that when the frequency is lower than 1 kHz, it is easily affected by the inductance and it is difficult to superimpose the AC voltage. On the other hand, when the frequency is higher than 30 kHz, the capacitance is low. This is because it tends to be easily affected.

  More preferably, the frequency is 1 kHz to 10 kHz. In this case, the determination means 3 has a characteristic such as impedance detected from the current received by the reception means 2 as to the presence / absence of this other point (whether or not the short-circuit grounding device 200 is removed except for the confirmation point). ), The difference appears prominently, and the removal status of the short-circuit grounding device 200 at other points can be more accurately determined.

  The receiving means 2 receives a current flowing through one or more other distribution lines 100. As shown in FIG. 1, the receiving means 2 is connected to another short-circuit wire 201 different from the short-circuit wire 201 to which the transmission means 1 applied an AC voltage by using a current transformer (CT) 21. Thus, it is possible to connect to the short-circuit line 201 in a non-contact manner. In addition to being connected to the short-circuit line 201, the receiving means 2 is connected using CT to another distribution line 100 different from the distribution line 100 to which the transmission means 1 applied an AC voltage. By doing so, it is possible to connect to the distribution line 100 without contact.

  In this determination means 3, to determine the removal status of the short-circuit grounding device 200 at another point means that after the distribution line power failure work, the short-circuit grounding device 200 connected to other points other than the above-mentioned confirmation points in the distribution line power failure section. This means that the presence or absence of the ground is determined, and is also referred to as ground short circuit determination.

  The determining means 3 is not particularly limited as long as it uses the current received by the receiving means 2 when determining the ground short-circuit, but it has been received by the receiving means 2 from the viewpoint of the accuracy of the ground short-circuit determining. It is preferable to detect the impedance (conductor resistance) from the current and determine the removal status of the short-circuit grounding device 200 at the other point based on this impedance.

  That is, as shown in FIG. 2, the determination unit 3 includes an impedance detection unit 31 that detects an impedance from the current received by the reception unit 2, and the short-circuit grounding device 200 at the other point based on the impedance. And a determination unit 32 that determines the removal status.

  In this way, it is possible to accurately determine the ground short-circuit by a simple configuration in which an AC voltage is applied between the short-circuit line 201 of the short-circuit grounding device 200 and the distribution line and the flowing current is detected. As for the current path of the flowing current, as shown in FIG. 3, when there is no short-circuit grounding location other than the confirmation point A (that is, in the case of one short-circuit grounding location), the arrow a in FIG. In addition, when the short-circuit ground location B remains in addition to the confirmation point A (that is, in the case of two short-circuit ground locations), the current path is indicated by the arrow a in FIG. Since there is an isolated difference in the characteristics (for example, impedance) of the flowing current, the determination unit 3 can easily determine whether there is one short-circuit ground location or a plurality of ground short-circuit locations. With such a configuration, since the ground resistance is negligible for the current received by the receiving means 2 and the influence of the capacitance of the pole transformer can be suppressed, the discriminating means 3 is reliably grounded with high accuracy. Short circuit discrimination can be performed.

  As described above, the determination unit 3 determines whether or not the short-circuit grounding device 200 exists other than the one point (confirmation point) based on the impedance calculated from the current received by the reception unit 2. Therefore, the removal status of the short-circuit grounding device 200 can be accurately determined without being affected by the grounding resistance, and the removal status of the short-circuiting grounding device 200 at the other point can be determined with higher accuracy.

Next, an equivalent circuit when an AC voltage is applied between the lines of the distribution line 100 as described above is shown in FIG. First, the path | route comprised via a pole transformer when an alternating voltage is applied between lines is shown by Fig.4 (a). Here, Z1 and Z2 indicate the impedance of the winding, and Cm indicates the capacitance between the primary winding and the secondary winding. Further, in the figure, since the path between the ground is not configured, the capacitance between the winding and the exterior is omitted. In addition, the path through the closed circuit Cm and Z2 in the figure is as small as Cm = 100 to 200 [pF], and the resonance frequency generally exceeds 1 MHz, so the impedance of the Cm / Z2 / Cm series circuit is Since it is sufficiently large with respect to Z1 and can be ignored, it can be regarded as a route passing only through Z1.

Based on FIG. 4A, a circuit configured when an AC voltage is applied between lines in a situation where a plurality of pole transformers are connected to a distribution line is shown in FIGS. 4B and 4C. ).

First, FIG. 4B shows a circuit configured by applying an AC voltage between the lines of the distribution line 100 in the case of one short-circuit ground point. Here, C represents the interphase capacitance, and L1 to Ln represent the inductance of the primary winding of the transformer. Note that the impedance of the primary winding under the application condition of the present invention is expressed as L1 to Ln because the influence of the inductance is dominant as can be seen from the measurement result of FIG.

Next, FIG. 4C shows a circuit configured by applying an AC voltage between the wires in the case of two short-circuit grounding locations. In the figure, r indicates the conductor resistance. That is, when the short-circuit grounding device 200 is connected in addition to the confirmation point, the impedance of the circuit is only the conductor resistance.

  The following relational expression is established for the line capacity Cm of the distribution line 100.

Formula 1

（r：導体半径[m]、D：配電線の線間距離[m]）

(R: conductor radius [m], D: distance between distribution lines [m])

Here, high-voltage overhead distribution lines are defined as OE and OC diameters of 4 mm or more (copper wire 38 mm ² or more, aluminum wire 32 mm ² or more are standard) (Electronic Interpretation Articles 65 and 66), Applying the above equation, Cm = 14.19 [nF / km] can be derived. The maximum conductor resistance is OE, OC: 0.502 Ω / km (38 mm ² ), ACSR-OC, ACSR-OE: 0.928 Ω / km (38 mm ² ).

As described above, since the synthetic impedance of the circuit is greatly different between the circuits of FIG. 4B and FIG. 4C, the discriminating means 3 has the synthetic impedance of the circuit shown in FIG. In the range larger than the combined impedance of the circuit shown in (c), it is possible to easily determine the ground short circuit while ignoring the influence of the ground resistance.

  Further, the impedance due to the inductance of the primary winding of the pole transformer becomes smaller in accordance with the number of pole transformers, but the impedance due to the inductance increases in proportion to the frequency, so that the AC voltage applied by the transmission means 1 is increased. It is possible to increase the impedance by setting a high frequency. Since the inductance of the winding has a frequency characteristic, it is important to analyze the frequency characteristic and set it to the optimum frequency when performing the ground short-circuit determination. However, as described above, the alternating current applied by the transmission unit 1 The voltage is preferably a frequency of 1 kHz to 30 kHz, and more preferably a frequency of 1 kHz to 10 kHz.

  Since the inductance of the winding varies with frequency, the frequency characteristics of the inductance of the primary winding of the pole transformer were analyzed. FIG. 5 is a graph showing the frequency characteristics of the inductance of the primary winding of the pole transformer obtained for each of the plurality of pole transformers (capacities: 5 kVA, 10 kVA, 20 kVA, 30 kVA). Qualitatively the same results were obtained for all pole transformers.

Furthermore, the comparison result of the impedance conversion value of the inductance of the primary winding of the pole transformer and the impedance measurement value of the primary winding of the pole transformer is shown in FIG. From the obtained results, it was confirmed that the influence of inductance was dominant.

  Furthermore, based on the frequency characteristics of the inductance, the combined impedance for each frequency of the circuit shown in FIGS. 4A and 4B was calculated. The obtained results are shown in Tables 1 and 2 as changes in impedance for each frequency.

In Tables 1 and 2, the following abbreviations are used.
Ln: Inductance of primary winding of pole transformer
Z: Impedance of primary winding
C: Capacity between distribution lines
Zc: Impedance due to the capacitance between the distribution lines
Zcl: Composite impedance between lines

(1) Change in impedance for each frequency (when pole transformers are installed at intervals of 30m)

(2) Change in impedance at each frequency (when pole transformers are installed at 100m intervals)

  If the combined impedance (Zcl) value between the above lines is within a range larger than the conductor resistance (r) shown in the circuit of FIG. Since it is possible to determine whether or not the short-circuit grounding device 200 is connected at the other point other than the point, whether or not the short-circuiting grounding device 200 is removed at the other point other than the confirmation point is determined as a ground short-circuit determination. Is possible.

  In consideration of the fact that the conductor resistance is OE, OC: 0.502Ω / km, ACSR-OC, ACSR-OE: 0.928Ω / km and the ground resistance is negligible from the obtained results, the transmission means 1 By using a frequency of 1 to 30 kHz as the frequency of the AC voltage applied by the power supply, it is possible to easily determine the ground short circuit even for large-scale facilities with a power outage section of 3 km and a number of pole transformers of 100. It was confirmed that this was preferable.

  Further, when the transmission means 1 uses a frequency of 1 kHz to 10 kHz in particular within this range, the inductance value of the vertical axis in FIG. On the other hand, it was confirmed that it is more preferable because the ground short circuit can be more clearly identified.

  As shown in FIG. 7A, the ground short-circuit discrimination device according to the present embodiment is composed of a transmitter 10 composed of transmission means 1 and a receiver 20 composed of reception means 2 and discrimination means 3. Since the transmitter 10 and the receiver 20 can be easily carried, it is possible to make a simple determination for each distribution line 100 in a non-contact manner. In addition, since the receiver 20 has a function of displaying the result of determination by the determination means 3 with an LED and an alarm function using a buzzer, the determination result is displayed to the user in an easy-to-understand manner. A good ground short-circuit discrimination device can be obtained.

  Further, the transmission means 1 can transmit the current by simultaneously applying the AC voltage not only to one distribution line 100 but also to a plurality of distribution lines 100, and the reception means 2 also Current can be received not only from one distribution line 100 but also from a plurality of distribution lines 100. For example, by providing a plurality of the transmitters 10 and / or the receivers 20, the plurality of current transformers 11 and the plurality of current transformers 21 are configured as shown in FIG. In addition, it is possible to efficiently determine the ground short circuit for the plurality of distribution lines 100.

  With such a configuration, the work load is reduced and the time is more efficient and limited than when transmitting and / or receiving current for each of the plurality of distribution lines 100 one by one. Therefore, the workability during the power outage work time is good and the grounding short circuit can be accurately identified.

  Furthermore, in the ground short-circuit determination device according to the present embodiment, a wireless device 30 that communicates wirelessly with the transmitter 10 and / or the receiver 20 can be additionally configured. For example, as shown in FIG. 8A, the wireless device 30 can function as a wireless receiver having a function of performing wireless communication with the receiver 20 and displaying the result of determination by the determination means 3 in an LED. In addition, it is possible to visually and / or audibly confirm the result of the ground short circuit determination at the user's hand, and the convenience is further improved.

  Further, for example, as shown in FIG. 8B, the radio device 30 has a function of wirelessly communicating with the transmitter 10 and the receiver 20 and displaying the result of discrimination in the discrimination means 3 with an LED. It can function as a wireless receiver and a wireless transmitter, and controls the voltage application at the transmission means 1 (instructing the current transmission) at the user's hand, and the result of the ground short circuit determination by the determination means 3 It can be confirmed and the convenience is further improved.

(Second Embodiment)
A ground short-circuit determination device according to a second embodiment of the present application will be described with reference to the block diagram of FIG.

  The ground short-circuit determination device according to the second embodiment includes the transmission unit 1, the reception unit 2, and the determination unit 3, similar to the ground short-circuit determination device according to the first embodiment. As shown in FIG. 8, the transmission means 1 applies an alternating voltage of 1 kHz to 10 kHz to transmit current, and the determination means 3 cannot determine the removal status of the short-circuit grounding device 200 at the other point. In this case, the transmission means 1 further includes a discrimination control unit 33 that performs control to apply an AC voltage of 10 kHz to 30 kHz.

  With this configuration, first, as shown in FIG. 5, Table 1 and Table 2 described above, an AC voltage having a frequency of 1 kHz to 10 kHz, in which the discriminating means 3 is more likely to detect (easy to discriminate) the amount of change in impedance. By applying the above, discrimination with high accuracy is performed. Even if this determination is not possible, the transmission means 1 applies an AC voltage having a frequency of 10 kHz to 30 kHz and transmits an electric current, so that additional determination can be made, and more reliably at the other points. The removal status of the short-circuit grounding device 200 can be determined.

1 Transmitting means 10 Transmitter 11 Current transformer (CT)
2 Receiving means 20 Receiver 21 Current transformer (CT)
3 Discriminating means 30 Radio device 31 Impedance detection unit 32 Discrimination unit 33 Discrimination control unit 100 Distribution line 200 Short-circuit grounding fixture 201 Short-circuit line

Claims (5)

In a short-circuit grounding device having a short-circuit line for short-circuiting the distribution line, in order to determine the removal status of the short-circuit grounding device respectively disposed at one point and the other point,
Transmitting means for applying an alternating voltage to transmit current to at least one distribution line at the one point;
Receiving means for receiving current flowing in one or more other distribution lines at the one point;
Discriminating means for discriminating the removal status of the short-circuit grounding device at the other point based on the current received by the receiving means;
A grounding short-circuit discrimination device. In the ground short circuit determination device according to claim 1,
The ground / short-circuit determination device, wherein the determination unit detects an impedance from the current received by the reception unit, and determines a removal state of the short-circuit grounding device at the other point based on the impedance. In the ground short-circuit determination device according to claim 1 or 2,
The transmission means applies an AC voltage of 1 kHz to 30 kHz and transmits an electric current. In the ground short circuit discrimination device according to any one of claims 1 to 3,
The transmitting means transmits an electric current by applying an alternating voltage of 1 kHz to 10 kHz,
The discriminating unit further includes a discriminating control unit for performing control to apply an AC voltage of 10 kHz to 30 kHz by the transmitting unit when the removal status of the short-circuit grounding device at the other point cannot be discriminated. A ground short-circuit detection device. In the ground short-circuit determination device according to any one of claims 1 to 4,
The grounding short-circuit determination device, wherein the transmission means transmits the current by simultaneously applying the AC voltage to the plurality of distribution lines.

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