JP2010271104A - Ground-fault position locating method and ground-fault position locating system for realizing the method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem, wherein there is a need to use instruments having a complex, enlarged apparatus (a mechanism for attaining synchronization of time between a first measuring instrument and a second measuring instrument, a GPS receiver, or the like). <P>SOLUTION: The first measuring instrument 200 transmits an electric signal 12 to the second measuring instrument 300 via a power supply line 10. The second measuring instrument measures an arrival time difference Δts required from the reception of the electrical signal to the reception of a noise signal 13. The first measuring instrument measures a total time T, required from the transmission of the electrical signal to the reception of a noise signal 14; acquires the arrival time difference Δts; and locates a ground-fault position through Xs=C×(T-Δts)/2, where Xs is the distance from the first measuring instrument to the ground-fault position and C is the velocity of a signal propagating through the line. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a ground fault position locating method for locating the occurrence position when a ground fault occurs in a power supply line, and a ground fault position locating system for realizing the method.

Conventionally, there is a system that uses a transmitter, a first measuring device, and a second measuring device as a system for realizing the ground fault location method (see, for example, Patent Document 1).
In the system disclosed in Patent Document 1, a transmitter and a first measuring device are installed on one end side of a stop distribution line, and a second measuring device is installed on the other end side. The transmitter sends a high voltage pulse to each of the R phase, S phase, and T phase of the stop distribution line. The first measuring device and the second measuring device respectively compare the waveform of the healthy phase (that is, the phase in which no ground fault has occurred) with the waveform of the fault phase (that is, the phase in which the ground fault has occurred). Then, the reception time of the traveling wave from the failure point (that is, the noise signal generated by the discharge at the failure point) is measured. And a 1st measuring device and a 2nd measuring device standardize the distance from each measuring device to a failure point based on the difference of the reception time in both measuring devices.

  Further, as this kind of ground fault location system, there is a system that uses a GPS technology in a clock unit to measure a propagation time difference of a current generated at the failure point at both ends, thereby locating the failure point (for example, Non-Patent Document 1).

  In addition, as a ground fault location system of this type, an optical fiber cable with a built-in optical fiber distributed temperature sensor is installed along the power cable, and the temperature sensor detects the temperature rise due to an arc at the time of failure. There is one that determines a failure point based on a rise in temperature (for example, see Non-Patent Document 2).

JP-A-9-113571

Aihara Yasuhiko, Asakawa Masato, Yashiro Seiichi, Ooi Manabu, Suzuki Satoshi, Amano Kazuo, "Fault location system for ultra-high voltage power cables", Fujikura Technical Review No. 99, Fujikura Corporation, October 2000 Naoki Takinami, Takashi Chino, Kazuo Watanabe, Kazuo Amano, Yoshiharu Nakamura, "Cable fault location method using optical fiber distributed temperature sensor-Examination of application and practical system for connection", Fujikura Technical Report No.99 , Fujikura Corporation, October 2000

  However, each of the systems disclosed in Patent Document 1, Non-Patent Document 1, and Non-Patent Document 2 needs to use devices with complicated and large-sized configurations as described below. There was a problem of being.

For example, in the system disclosed in Patent Document 1, since it is necessary for the first measuring device and the second measuring device to measure time in synchronization, the time is measured between the first measuring device and the second measuring device. A mechanism to synchronize was necessary.
In addition, since this system needs to specify the distance between the first measuring device and the second measuring device, a mechanism for specifying the position of the first measuring device and the position of the second measuring device (specifically Requires a GPS (Global Positioning System) receiver.
In addition, since this system requires a high voltage pulse to flow through each phase of the line, a transmitter having a high voltage generation function for flowing the high voltage pulse is required.
For this reason, the system disclosed in Patent Document 1 needs to use a device whose configuration is complicated and large.
Such a system disclosed in Patent Document 1 is (1) expensive to manufacture equipment, (2) cannot locate a ground fault position in a place where radio waves from a GPS geodetic satellite cannot be received, ( 3) There were problems such as forcing the operator to carry out the work burden for transporting and installing the equipment.

Further, for example, the system disclosed in Non-Patent Document 1 uses GPS technology as a mechanism for synchronizing time between the first measuring device and the second measuring device.
For this reason, the system disclosed in Non-Patent Document 1 needs to use a device having a complicated configuration.
Such a system disclosed in Non-Patent Document 1 has (1) cost for manufacturing equipment, (2) ground fault position cannot be determined in a place where radio waves from GPS geodetic satellites cannot be received, etc. There was a problem.

Further, for example, in the system disclosed in Non-Patent Document 2, an optical fiber cable incorporating an optical fiber distributed temperature sensor is installed along a power cable.
For this reason, the system disclosed in Non-Patent Document 2 needs to use a device whose configuration is complicated and large.
Such a system disclosed in Non-Patent Document 2 has problems such as (1) cost for manufacturing equipment and (2) forcing an operator to work on installing an optical fiber cable. It was.

  The present invention has been made to solve the above-described problem, and is a device whose configuration is simplified and miniaturized (that is, for synchronizing time between the first measuring device and the second measuring device). The main purpose is to provide a ground fault position locating method for locating the ground fault position and a ground fault position locating system for realizing the method using a mechanism that does not include the structure of the GPS receiver or a GPS receiver). And

In order to achieve the object, the ground fault location method according to the first invention uses a first measuring device installed on one end side of the power supply line and a second measuring device installed on the other end side, A ground fault position locating method for locating a position of a ground fault generated in the power supply line, wherein the first measuring device generates a predetermined electrical signal and passes the electrical signal through the power supply line. Is transmitted to the second measuring device, and the second measuring device calculates a difference in arrival time from the time when the second measuring device receives the electrical signal to the time when the noise signal generated by the ground fault is received. The first measuring device measures the time taken from when the first measuring device transmits the electrical signal until it receives the noise signal as the total time, and the second measuring device Obtaining the measured arrival time difference, and When the distance from the first measuring device to the position of the ground fault is Xs, the arrival time difference is Δts, the total time is T, and the speed of the signal propagating through the power supply line is C, The position of the ground fault is determined by the following equation (1).
Xs = C × (T−Δts) / 2 (1)

In order to achieve the above object, the ground fault location system according to the second invention uses a first measuring device installed on one end side of the power supply line and a second measuring device installed on the other end side, A ground fault position locating system for locating the position of a ground fault generated in the power supply line, wherein the first measuring device is configured to generate a predetermined electrical signal via the power supply line, A first transmitter for transmitting the electric signal generated by the electric signal generator to the second measuring device; a first receiver for receiving a propagation signal propagating on the power supply line; and the first receiver. A first noise signal detection unit that detects a noise signal generated by the ground fault according to the electrical signal from the propagation signal received by the unit, and the first measuring device transmits the electrical signal. Until the noise signal is received from The electrical signal includes: a total time measuring unit that measures the measured time as a total time; and a ground fault position locating unit that determines the position of the ground fault, wherein the second measuring device propagates on the power supply line. A second reception unit that receives the propagation signal including the noise signal, a second noise signal detection unit that detects the noise signal from the propagation signal received by the second reception unit, and the second An arrival time difference measuring unit that measures the time required from when the measuring device receives the electrical signal until the noise signal is received as an arrival time difference, and the ground fault location unit of the first measuring device Obtains the arrival time difference measured by the arrival time difference measuring unit of the second measuring device, further sets the distance from the first measuring device to the position of the ground fault as Xs, and sets the arrival time difference as Δts. The above When the total time is T and the speed of a signal propagating through the power supply line is C, the position of the ground fault is determined by the following equation (1).
Xs = C × (T−Δts) / 2 (1)

In the ground fault location method of the first invention and the ground fault location system of the second invention, the first measuring device and the second measuring device synchronize the time between the first measuring device and the second measuring device. Independently, the ground fault position can be determined only by measuring the time required for the required operation as a value for determining the ground fault position.
Therefore, the ground fault position locating method of the first invention and the ground fault position locating system of the second invention only require that the first measuring device and the second measuring device have a function of measuring time independently. The mechanism for synchronizing the time between the first measuring device and the second measuring device, the GPS receiver, etc. can be deleted from the measuring device and the second measuring device, whereby the first measuring device and the second measuring device can be deleted. The configuration of the measuring instrument can be simplified and miniaturized.

According to the first aspect of the present invention, it is possible to provide a ground fault position locating method for locating a ground fault position using a device whose configuration is simplified and miniaturized.
Moreover, according to the 2nd invention, the ground fault location system for implement | achieving the method of the 1st invention can be provided.

It is explanatory drawing (1) of the ground fault location method based on this invention. It is explanatory drawing (2) of the ground fault location method based on this invention. It is a flowchart which shows the process process of the ground fault location method based on this invention. It is a lineblock diagram (1) of a ground fault location system concerning Embodiment 1. It is a block diagram (2) of the ground fault location system concerning Embodiment 1. It is a block diagram of the ground fault location system concerning Embodiment 2. It is a block diagram (1) of the ground fault location system concerning Embodiment 3. It is a block diagram (2) of the ground fault location system concerning Embodiment 3. It is operation | movement explanatory drawing of the ground fault location system concerning Embodiment 3. It is a block diagram of the ground fault location system concerning Embodiment 4.

  Hereinafter, an embodiment of the present invention (hereinafter referred to as “the present embodiment”) will be described in detail with reference to the drawings. Each figure is only schematically shown so that the present invention can be fully understood. Therefore, the present invention is not limited to the illustrated example. Moreover, in each figure, the same code | symbol is attached | subjected about the common component and the same component, and those overlapping description is abbreviate | omitted.

[Embodiment 1]
<Ground fault location method>
Hereinafter, the ground fault location method according to the present invention will be described with reference to FIGS. 1 to 3. 1 and 2 are explanatory diagrams of the ground fault location method according to the present invention, respectively. FIG. 1 shows the configuration of a ground fault location system for realizing the ground fault location method according to the present invention. On the other hand, FIG. 2 shows the relationship between the distance (x) and the time (t) through which the signal used in the ground fault location method according to the present invention propagates. FIG. 3 is a flowchart showing the processing steps of the ground fault location method according to the present invention.

  As shown in FIG. 1, a ground fault location system 100 according to the present invention includes a power supply line (however, a line in which power distribution is stopped, that is, a stopped distribution line) 10 (hereinafter simply referred to as “line 10”). The first measuring device 200 is installed at one end of the second measuring device 300, and the second measuring device 300 is installed at the other end.

  The first measuring device 200 measures an overall time T described later, and based on the overall time T and an arrival time difference Δts described later, a failure point, that is, a position where a ground fault (including a short circuit) occurs (hereinafter referred to as “ground fault”). It is a device for locating the position. The first measuring device 200 has a function of generating the electrical signal 12 (see FIG. 2) and transmitting it to the second measuring device 300.

  On the other hand, the second measuring device 300 is a device that measures an arrival time difference Δts described later. In the example shown in FIG. 2, the second measuring device 300 is set at a distance L from the first measuring device 200 with the position of the first measuring device 200 as the origin 0.

  Here, the line 10 is configured in three phases, and one of the phases (for example, the phase R) is a fault phase (that is, a phase in which a ground fault (including a short circuit) occurs). It shall be. Here, as shown in FIG. 2, the fault phase is assumed to have a ground fault at a position at a distance Xs from the first measuring device 200.

  In the ground fault location system 100 according to the present invention, the first measuring device 200 generates the electric signal 12 and transmits it to the second measuring device 300 via the line 10 (see S105 in FIG. 3). In the example shown in FIG. 2, the first measuring device 200 transmits the electrical signal 12 at time t0. Hereinafter, the time t0 at this time is referred to as “electric signal transmission start time”.

  When the first measuring device 200 transmits the electric signal 12, the first measuring device 200 starts measuring the total time T. The “total time T” means the time required for the first measuring instrument 200 to receive the noise signal 14 described later after transmitting the electrical signal 12.

  The electric signal 12 propagates through a healthy phase (for example, phase S) of the line 10 at a predetermined speed C (specifically, a speed of about 300,000 km / s) and eventually reaches the second measuring device 300. . In the example illustrated in FIG. 2, the electric signal 12 reaches the second measuring device 300 at time t <b> 2, and the second measuring device 300 receives the electric signal 12. Hereinafter, the time t2 at this time is referred to as “second measuring instrument electrical signal reception start time”.

  When receiving the electrical signal 12, the second measuring device 300 starts measuring the arrival time difference Δts. This “arrival time difference Δts” means the time required for the second measuring device 300 to receive the noise signal 13 described later after receiving the electrical signal 12.

  In the fault phase of the line 10, a ground fault occurs at a distance Xs from the first measuring device 200. Therefore, discharge occurs in the fault phase of the line 10, thereby generating a noise signal. Hereinafter, the time ts when the noise signal is generated is referred to as “ground fault time”.

  The noise signal generated by the ground fault propagates toward both the second measuring device 300 and the first measuring device 200. Hereinafter, the noise signal propagating toward the second measuring device 300 is referred to as “noise signal 13”, and the noise signal propagating toward the second measuring device 300 is referred to as “noise signal 14”.

  The noise signal 13 propagates through the failure phase of the line 10 at a predetermined speed C (specifically, a speed of about 300,000 km / s) and eventually reaches the second measuring device 300. In the example shown in FIG. 2, the noise signal 13 reaches the second measuring device 300 at time t3, and the second measuring device 300 receives the noise signal 13. Hereinafter, the time t3 at this time is referred to as “second measuring instrument noise signal reception time”.

  On the other hand, the noise signal 14 propagates through the failure phase of the line 10 at a predetermined speed C (specifically, a speed of about 300,000 km / s), and eventually reaches the first measuring device 200. In the example illustrated in FIG. 2, the noise signal 14 reaches the first measuring device 200 at time t4, and the first measuring device 200 receives the noise signal 14. Hereinafter, the time t4 at this time is referred to as “first measuring instrument noise signal reception time”.

  When the second measuring device 300 receives the noise signal 13, the time from the second measuring device electrical signal reception start time t2 to the second measuring device noise signal receiving time t3 is regarded as the arrival time difference Δts, and the arrival time difference Δts is measured. (See S110 in FIG. 3).

  On the other hand, when receiving the noise signal 14, the first measuring device 200 regards the time from the electric signal transmission start time t0 to the first measuring device noise signal reception time t4 as the total time T, and ends the measurement of the total time T. (Refer to S115 in FIG. 3).

Thereafter, the first measuring device 200 acquires the arrival time difference Δts measured by the second measuring device 300 (see S120 in FIG. 3).
The arrival time difference Δts is acquired from, for example, a signal that notifies the first measurement device 200 of the arrival time difference Δts (hereinafter referred to as “arrival time difference notification signal”) from the second measurement device 300 via the line 10. This is performed by being transmitted to the measuring device 200.
Alternatively, the arrival time difference Δts is acquired by, for example, a person who operates the second measuring device 300 confirms the arrival time difference Δts measured by the second measuring device 300, and the value is first transmitted by a transmission means such as telephone or mail. This is performed by notifying the person who operates the measuring device 200 and inputting the value to the first measuring device 200 by the person who operates the first measuring device 200.

  When acquiring the arrival time difference Δts, the first measuring device 200 specifies (calculates) the ground fault position arrival time Txs (see FIG. 2) of the signal based on the following principle (see S125 in FIG. 3). The “signal ground fault position arrival time Txs” means the time required for the signal propagating on the line 10 to reach the ground fault position Xs from the origin 0.

  Here, it is assumed that the first measuring device 200 transmits the noise signal 13 virtually, and the time when the first measuring device 200 transmits the noise signal 13 is “t1”. Hereinafter, the time t1 at this time is referred to as a “noise signal virtual transmission time”. The virtual signal transmission time t1 of this noise signal is the time after the arrival time difference Δts from the electric signal transmission start time t0.

Here, in FIG. 2, when attention is paid to a triangle having a time (t) from time t1 to t4 as a base and a distance (x) from the origin 0 to Xs as a height, this triangle has an isosceles triangle shape. There is no.
The value of the time for forming the base of the isosceles triangle is “T−ΔTs”.
In addition, a value that is half the time for forming the base (that is, “(T−ΔTs) / 2”) is the ground fault position arrival time Txs of the signal.
Therefore, the first measuring device 200 can specify the signal ground fault position arrival time Txs by calculating “Txs = (T−ΔTs) / 2”.

  Then, the 1st measuring device 200 locates a ground fault position by the following formula | equation (1) using the ground fault position arrival time Txs of the identified signal (refer S130 of FIG. 3).

Xs = C × Txs = C × (T−Δts) / 2 (1)
Where each symbol is
Xs: distance from the first measuring device 200 to the ground fault position,
C: Speed of signal propagating through the power supply line 10 (about 300,000 km / s),
t0: electrical signal transmission start time (time when the first measuring device 200 transmits the electrical signal 12),
t4: the first measuring device noise signal reception time (the time when the first measuring device 200 received the noise signal 14),
Δts: arrival time difference (time difference from the time when the second measuring device 300 receives the electrical signal 12 to the time when the noise signal 13 is received),
Means.

The ground fault position locating system 100 ends the series of processes by the first measuring device 200 locating the ground fault position.
The first measuring device noise signal reception time t4 is the second measuring device noise signal reception when the ground fault position is closer to the first measuring device 200 than the middle between the first measuring device 200 and the second measuring device 300. It becomes earlier than time t3. Even in this case, the ground fault position locating system 100 can determine the ground fault position by the equation (1).

By the way, the total time T of the above-described equation (1) is the time that the first measuring device 200 is independent of the second measuring device 300 (that is, regardless of the time measured by the second measuring device 300). It is specified by measuring the time from t0 to time t4. In addition, the arrival time difference Δts of the above-described equation (1) is determined by the second measuring device 300 independently of the first measuring device 200 (that is, regardless of the time measured by the first measuring device 200). It is specified by measuring the time from t2 to time t3.
Therefore, the ground fault position locating system 100 does not need to synchronize the time between the first measuring device 200 and the second measuring device 300 when locating the ground fault position. Therefore, unlike the system disclosed in Patent Document 1 and the system disclosed in Non-Patent Document 1, the ground fault location system 100 sets the time between the first measuring device 200 and the second measuring device 300. It can be set as the structure which does not have the mechanism for synchronizing, a GPS receiver, etc.

<Specific configuration of ground fault location system>
Hereinafter, a specific configuration of the ground fault location system 100 according to the first embodiment will be described with reference to FIGS. 4 and 5. 4 and 5 are configuration diagrams of the ground fault location system according to the first embodiment, respectively. Hereinafter, the first measuring device 200 according to the first embodiment is referred to as a “first measuring device 200a” in order to distinguish it from the first measuring device according to another embodiment, and the second measuring device according to the first embodiment. In order to distinguish the instrument 300 from the second instrument according to another embodiment, it is referred to as a “second instrument 300a”.

(Specific configuration of the first measuring device)
FIG. 4 shows a specific configuration of the first measuring device 200a.
As shown in FIG. 4, the first measuring device 200a includes a clock unit 205, an electric signal generation unit 210, and a transmission unit 215 as transmission-system functional units, and further includes a reception unit 225 as reception-system functional units. , A noise signal detection unit 260, an overall time specifying unit 266, an arrival time difference acquisition unit 270, an input unit 272, a ground fault position arrival time specifying unit 275, a ground fault position locating unit 280, and a display unit 285.

The clock unit 205 is a functional unit that measures time.
The electric signal generator 210 is a functional unit that generates the electric signal 12 (see FIG. 2). In the first embodiment, the electrical signal generation unit 210 is configured as a pulse signal generation unit 211 that generates a sine wave pulse signal having a predetermined period.
The transmission unit 215 is a functional unit that transmits the electrical signal 12 generated by the electrical signal generation unit 210 to the second measuring device 300 a via the line 10.

The receiving unit 225 is a functional unit that receives a signal propagating through the line 10 (hereinafter referred to as “propagation signal”). The first measuring device 200a receives the noise signal 14 (see FIG. 2) from the second measuring device 300a as a propagation signal, and further receives the arrival time difference notification signal described above.
The noise signal detection unit 260 is a functional unit that detects the noise signal 14 from the propagation signals received by the reception unit 225.
The total time specifying unit 266 is a functional unit that specifies (calculates) the total time T described above. The total time specifying unit 266 and the clock unit 205 constitute a total time measuring unit 265 that measures the total time T.

The arrival time difference acquisition unit 270 is a functional unit that acquires the arrival time difference Δts described above. In the first embodiment, the arrival time difference acquisition unit 270 is configured as an arrival time difference notification signal detection unit 271 that detects the arrival time difference notification signal described above from the propagation signals received by the reception unit 225.
The input unit 272 is configured by a keyboard such as a numeric keypad. The input unit 272 is used as input means when a person operating the first measuring device 200 inputs the arrival time difference Δts to the first measuring device 200.

The ground fault position arrival time specifying unit 275 is a functional unit that specifies (calculates) the ground fault position arrival time Txs of the signal described above.
The ground fault position locating unit 280 is a functional means for locating the ground fault position.
The display unit 285 is configured by a display such as a liquid crystal. The display unit 285 displays the distance Xs from the first measuring device 200a determined by the ground fault position locating unit 280 to the ground fault position.

(Specific configuration of the second measuring device)
FIG. 5 shows a specific configuration of the second measuring device 300a.
As shown in FIG. 5, the second measuring device 300a includes a receiving unit 310, an electric signal detecting unit 320, a noise signal detecting unit 330, a clock unit 340, and an arrival time difference measuring unit 350 as functional units of the receiving system. Furthermore, an arrival time difference notification unit 360 and a transmission unit 370 are provided as functional units of the transmission system.

The receiving unit 310 is a functional unit that receives a propagation signal propagating through the line 10. The second measuring device 300a receives the electric signal 12 (see FIG. 2) and the noise signal 13 (see FIG. 2) from the first measuring device 200a as the propagation signal.
The electric signal detection unit 320 is a functional unit that detects the electric signal 12 from the propagation signals received by the reception unit 310. In the first embodiment, the electric signal detector 320 is configured as a pulse signal detector 321 that detects a sinusoidal pulse signal from the propagation signal.
The noise signal detection unit 330 is a functional unit that detects the noise signal 13 from the propagation signals received by the reception unit 310.

  The clock unit 340 is a functional unit that measures time. The clock unit 340 may not be synchronized with the clock unit 205 of the first measuring device 200. That is, the time measured by the clock unit 340 may be different from the time measured by the clock unit 205.

  The arrival time difference measurement unit 350 is a functional unit that measures the arrival time difference Δts. In the first embodiment, the arrival time difference measurement unit 350 is configured as a pulse signal reception time determination unit 351, a noise signal reception time determination unit 352, and an arrival time difference identification unit 353.

The pulse signal reception time determination unit 351 is a functional unit that determines the above-described second measuring device electrical signal reception start time t2 (see FIG. 2) with reference to the time measured by the clock unit 340.
The noise signal reception time determination unit 352 is a functional unit that determines the second measuring device noise signal reception time t3 (see FIG. 2) with reference to the time measured by the clock unit 340.
The arrival time difference specifying unit 353 is a functional unit that specifies (calculates) the arrival time difference Δts. The arrival time difference specifying unit 353 calculates the second measuring device electrical signal reception start time t2 determined by the pulse signal receiving time determination unit 351 from the second measuring device noise signal reception time t3 determined by the noise signal reception time determination unit 352. By subtracting, the arrival time difference Δts is specified.

The arrival time difference notification unit 360 is a functional unit that notifies the first measurement device 200a of the arrival time difference Δts measured by the arrival time difference measurement unit 350. In the first embodiment, the arrival time difference notification unit 360 is configured as an arrival time difference notification signal generation unit 361 that generates the arrival time difference notification signal described above.
The transmission unit 370 is a functional unit that transmits the arrival time difference notification signal generated by the arrival time difference notification signal generation unit 361 to the first measuring device 200 a via the line 10.

<Specific operation of ground fault location system>
Hereinafter, operations of the first measuring device 200a and the second measuring device 300a according to the first embodiment will be described.

  As shown in FIG. 3, in the ground fault location system 100, the first measuring device 200a performs an “electric signal generation / transmission” process in accordance with the operation of the person who operates the first measuring device 200a (see S105). ). This process is performed as follows.

  First, in the first measuring instrument 200 a, the pulse signal generation unit 211 of the electrical signal generation unit 210 generates a sine wave pulse signal having a predetermined cycle and outputs it to the transmission unit 215. The transmission unit 215 transmits the pulse signal as the electric signal 12 (see FIG. 2) to the second measuring device 300a via the line 10.

In the first measuring instrument 200a, when the transmitting unit 215 transmits the electrical signal 12, the total time specifying unit 266 acquires the time at that time (here, time t0 (see FIG. 2)) from the clock unit 205. The time t0 is stored in the storage unit (not shown) as the electric signal transmission start time. Thereby, the total time specifying unit 266 starts measuring the total time T.
In this way, the process of S105 ("electric signal generation / transmission" process) is performed.

  On the other hand, the second measuring device 300a performs an “arrival time difference measurement” process in accordance with the operation of the person who operates the second measuring device 300a (see S110). This process is performed as follows.

  That is, in the second measuring device 300a, the receiving unit 310 always receives a propagation signal that propagates through the line 10, and the received propagation signal is transmitted to the pulse signal detection unit 321 and the noise signal detection unit 330 of the electric signal detection unit 320. Output to.

When the electric signal 12 is included in the propagation signal, the pulse signal detection unit 321 detects the electric signal 12 and notifies the detection of the electric signal 12 (hereinafter referred to as “detection signal”). ) Is output to the pulse signal reception time determination unit 351 of the arrival time difference measurement unit 350.
When the detection signal of the electric signal 12 is input from the pulse signal detection unit 321, the pulse signal reception time determination unit 351 acquires the current time (here, time t 2 (see FIG. 2)) from the clock unit 340. Then, the time t2 is output to the arrival time difference specifying unit 353.
The arrival time difference specifying unit 353 stores the time t2 in a storage unit (not shown) and starts measuring the arrival time difference Δts.

On the other hand, when the noise signal 13 (see FIG. 2) is included in the propagation signal, the noise signal detection unit 330 detects the noise signal 13, and uses the detection signal of the noise signal 13 as the arrival time difference measurement unit 350. Output to the noise signal reception time determination unit 352.
When the noise signal reception time determination unit 352 receives the detection signal of the noise signal 13 from the noise signal detection unit 330, the noise signal reception time determination unit 352 acquires the current time (here, time t3 (see FIG. 2)) from the clock unit 340. The time t3 is output to the arrival time difference specifying unit 353.
The arrival time difference specifying unit 353 stores the time t3 in a storage unit (not shown).

Thereafter, the arrival time difference specifying unit 353 reads the time t2 and the time t3 from a storage unit (not shown), and specifies (calculates) the time (t3−t2) obtained by subtracting the time t2 from the time t3 as the arrival time difference Δts. .
When the arrival time difference identifying unit 353 identifies the arrival time difference Δts, the arrival time difference identifying unit 353 outputs the identified arrival time difference Δts to the arrival time difference notification signal generating unit 361 of the arrival time difference notifying unit 360.

When arrival time difference Δts is input from arrival time difference specifying section 353, arrival time difference notification signal generating section 361 generates an arrival time difference notification signal and outputs it to transmission section 370. The transmission unit 370 transmits the arrival time difference notification signal to the first measuring device 200 a via the line 10.
In this way, the process of S110 ("arrival time difference measurement" process) is performed.

  After S105, the first measuring device 200a performs the "total time measurement" process in parallel with the process of S110 ("arrival time difference measurement" process) (see S115). This process is performed as follows.

  That is, in the first measuring device 200a, the receiving unit 225 always receives a propagation signal that propagates through the line 10, and outputs the received propagation signal to the noise signal detection unit 260 and the arrival time difference acquisition unit 270.

When the noise signal 14 (see FIG. 2) is included in the propagation signal, the noise signal detection unit 260 detects the noise signal 14 and uses the detection signal of the noise signal 14 as the total time of the total time measurement unit 265. The data is output to the specifying unit 266.
When the detection signal of the noise signal 14 is input from the noise signal detection unit 260, the total time specifying unit 266 acquires the time at that time (here, time t4 (see FIG. 2)) from the clock unit 205. The time t3 is stored in a storage unit (not shown).

  Thereafter, the total time specifying unit 266 reads the time t0 and the time t4 from a storage unit (not shown), and specifies (calculates) the time (t4-t0) obtained by subtracting the time t0 from the time t4 as the total time T. .

When the total time T is specified, the total time specifying unit 266 outputs the specified total time T to the ground fault position arrival time specifying unit 275.
The ground fault position arrival time specifying unit 275 stores the entire time T in a storage unit (not shown).
In this way, the process of S115 ("total time measurement" process) is performed.

  After S115, the first measuring device 200a performs an “arrival time difference acquisition” process (see S120). This process is performed as follows.

That is, when the arrival time difference notification signal is included in the propagation signal, the arrival time difference acquisition unit 270 detects the arrival time difference notification signal 271 and detects the arrival time difference from the arrival time difference notification signal. Δts is extracted. Then, arrival time difference acquisition section 270 outputs arrival time difference Δts to ground fault position arrival time identification section 275. The arrival time difference acquisition unit 270 outputs the input arrival time difference Δts to the ground fault position arrival time specifying unit 275 when the person operating the first measuring device 200a inputs the arrival time difference Δts from the input unit 272. To do.
When the arrival time difference Δts is input from the arrival time difference acquisition unit 270, the ground fault position arrival time specifying unit 275 stores the arrival time difference Δts in a storage unit (not shown).
In this way, the process of S120 ("arrival time difference acquisition" process) is performed.

  After S120, the first measuring device 200a performs a “signal ground fault position arrival time specification” process (see S125). This process is performed as follows.

That is, the ground fault position arrival time specifying unit 275 reads the total time T and the arrival time difference Δts from a storage unit (not shown), and subtracts the arrival time difference Δts from the total time T (“(T−Δts). ) / 2 ") is specified (calculated) as the ground fault position arrival time Txs of the signal.
When the ground fault position arrival time specifying unit 275 specifies the ground fault position arrival time Txs of the signal, the ground fault position arrival time Txs of the specified signal is output to the ground fault position locating unit 280.
In this way, the process of S125 ("signal ground fault position arrival time specification" process) is performed.

  After S125, the first measuring device 200a performs a “ground fault location” process (see S130). This process is performed as follows.

That is, when the ground fault position arrival time Txs of the signal is input from the ground fault position arrival time specifying unit 275, the ground fault position locating unit 280 determines the ground fault position by the above-described equation (1).
When the ground fault position locating unit 280 locates the ground fault position, the ground fault position 280 outputs the distance Xs from the first measuring device 200a to the ground fault position to the display unit 285, and causes the display unit 285 to display the distance Xs.
In this way, the process of S130 ("ground fault location determination" process) is performed.

  As described above, according to the ground fault location system 100 according to the first embodiment, the time is synchronized between the first measuring device 200 and the second measuring device 300 from the first measuring device 200 and the second measuring device 300. Therefore, the structure of the first measuring device and the second measuring device can be simplified and miniaturized.

According to the ground fault location system 100, compared with the system disclosed in Patent Document 1, (1) it is possible to reduce the cost for manufacturing the equipment, and (2) from the geodetic satellite for GPS. The ground fault position can be determined even in a place where radio waves cannot be received, and (3) the burden on the operator for transporting and installing the equipment can be reduced.
Further, according to the ground fault location system 100, compared with the system disclosed in Non-Patent Document 1, (1) the cost for manufacturing the device can be reduced, and (2) GPS geodetic measurement The ground fault position can be determined even in a place where radio waves from the satellite cannot be received.
Moreover, according to this ground fault location system 100, compared with the system disclosed by the nonpatent literature 2, (1) The cost for manufacturing an apparatus can be reduced, (2) Optical fiber cable It is possible to eliminate the work burden of the worker for laying.

[Embodiment 2]
The second embodiment is for simplifying the configuration of the second measuring device 300 by deleting the clock unit 340 from the second measuring device 300. The second embodiment is characterized in that the arrival time difference measuring unit 350 is configured as a timer 354 (see FIG. 6).

  Hereinafter, the configuration and operation of the second measuring device 300b according to the second embodiment will be described with reference to FIG. FIG. 6 is a configuration diagram of the ground fault location system according to the second embodiment. Here, the configuration and operation different from those of the first embodiment will be mainly described. Regarding the configuration and operation similar to those of the first embodiment, the configuration and operation of the first embodiment described above are the same as those of the second embodiment. Detailed description will be omitted as a replacement for operation.

  As shown in FIG. 6, the second measuring device 300 b is configured such that the clock unit 340 is deleted and the arrival time difference measuring unit 350 is configured as a timer 354 when compared with the second measuring device 300 a (see FIG. 5) according to the first embodiment. It is different in that it is.

  The timer 354 is a functional unit that measures the arrival time difference Δts. The timer 354 starts the operation of measuring the arrival time difference Δts triggered by the reception of the electric signal 12, stops the measurement operation of the arrival time difference Δts triggered by the reception of the noise signal 13, and holds the value. Thereby, the timer 354 measures the time from the start to the stop of the operation as the arrival time difference Δts.

  In the second embodiment, the second measuring device 300b outputs the detection signal of the electrical signal 12 to the timer 354 when the pulse signal detection unit 321 of the electrical signal detection unit 320 detects the electrical signal 12 from the propagation signal. . As a result, the timer 354 starts measuring the arrival time difference Δts.

  In addition, when the noise signal detection unit 330 detects the noise signal 13 from the propagation signal, the second measuring device 300b outputs a detection signal of the noise signal 13 to the timer 354. Accordingly, the timer 354 stops measuring the arrival time difference Δts.

  In the second measuring device 300b, the configuration of the arrival time difference measuring unit 350 is simplified compared to the first embodiment, and the clock unit 340 is deleted. Therefore, the second measuring device 300b is unlikely to fail. In addition, since the second measuring device 300b has few components, the processing speed can be improved.

  Thereafter, the second measuring device 300b outputs the time from the start to the stop of the measurement operation to the arrival time difference notification unit 360 as the arrival time difference Δts. In the second measuring device 300b, the arrival time difference notification signal generation unit 361 of the arrival time difference notification unit 360 generates the arrival time difference notification signal, and the transmission unit 370 is connected to the line, similarly to the second measurement device 300a of the first embodiment. 10, an arrival time difference notification signal is transmitted.

  Hereinafter, the first measuring device 200 according to the second embodiment operates in the same manner as the first measuring device 200a of the first embodiment, and determines the ground fault position.

  As described above, according to the second embodiment, the time is synchronized between the first measuring device 200 and the second measuring device 300 from the first measuring device 200 and the second measuring device 300 as in the first embodiment. Therefore, the structure of the first measuring device and the second measuring device can be simplified and miniaturized.

  Moreover, according to the second measuring device 300b according to the second embodiment, since the configuration is simplified compared to the second measuring device 300a according to the first embodiment, the occurrence of a failure can be suppressed, In addition, the processing speed can be improved.

[Embodiment 3]
As in the second embodiment, the third embodiment is for simplifying the configuration of the second measuring device 300 by deleting the clock unit 340 from the second measuring device 300. The third embodiment is characterized in that a pulse signal whose frequency periodically changes in a sawtooth shape with the passage of time (hereinafter simply referred to as “frequency fluctuation wave”) is used as the electric signal 12.

  Hereinafter, the configuration and operation of the ground fault location system according to the third embodiment will be described with reference to FIGS. 7 to 9. 7 and 8 are configuration diagrams of the ground fault location system according to the third embodiment, respectively. FIG. 7 shows a configuration of the first measuring device 200c according to the third embodiment. On the other hand, FIG. 8 shows a configuration of the second measuring device 300c according to the third embodiment. FIG. 9 is an operation explanatory diagram of the ground fault location system according to the third embodiment. Here, the configuration and operation different from those of the first embodiment will be described with emphasis, and the configuration and operation similar to those of the first embodiment are the same as those of the third embodiment. Detailed description will be omitted as a replacement for operation.

  As shown in FIG. 7, the first measuring device 200c according to the third embodiment is different from the first measuring device 200a according to the first embodiment (see FIG. 4) in that the electric signal generation unit 210 has a frequency fluctuation wave generation unit. It is different in that it is configured as 212.

  The frequency fluctuation wave generation unit 212 is a functional unit that generates a frequency fluctuation wave (that is, a pulse signal whose frequency periodically changes in a sawtooth shape with the passage of time).

  As shown in FIG. 8, the second measuring device 300 c according to the third embodiment is deleted from the second signal measuring device 300 a according to the first embodiment (see FIG. 5). The difference is that the arrival time difference measuring unit 350 is configured as a frequency analysis unit 355, a frequency corresponding time information storage unit 356, and an arrival time difference specifying unit 357.

The frequency analysis unit 355 is a functional unit.
The frequency-corresponding time information storage unit 356 is information (hereinafter referred to as “frequency-corresponding time information”) representing the relationship between the frequency of the frequency fluctuation wave and the time corresponding to the frequency (the elapsed time from the rise of the frequency fluctuation wave). Is a storage means for storing in advance.
The arrival time difference specifying unit 357 is a functional unit that specifies the arrival time difference Δts.

  In the third embodiment, in the first measuring device 200c, the frequency fluctuation wave generation unit 212 of the electric signal generation unit 210 generates a frequency fluctuation wave. As shown in FIG. 9, the frequency fluctuation wave increases at a constant rate from 0 Hz as time elapses until a predetermined time elapses from the rising edge of the signal. This is a pulse signal that repeats the operation of falling to 0 Hz.

  If the 1st measuring device 200c produces | generates a frequency fluctuation wave, the transmission part 215 will transmit a frequency fluctuation wave to the 2nd measuring device 300c as the electric signal 12 via the track | line 10. FIG.

  In the second measuring device 300c, the receiving unit 310 always receives a propagation signal propagating through the line 10, and the received propagation signal is sent to the frequency analysis unit 355 of the arrival time difference measurement unit 350 and the noise signal detection unit 330. Output.

When the propagation signal is input from the reception unit 310, the frequency analysis unit 355 of the arrival time difference measurement unit 350 analyzes the frequency of the head portion of the propagation signal. The leading portion of this propagation signal is the leading portion of the frequency fluctuation wave. Here, it is assumed that the frequency of the head portion of the propagation signal is “Ft2”. This frequency Ft2 represents the frequency at the time when the second measuring device 300c starts to receive the frequency fluctuation wave.
The frequency analysis unit 355 outputs the frequency Ft2 to the arrival time difference specifying unit 357.
The arrival time difference specifying unit 357 stores the frequency Ft2 in a storage unit (not shown).

On the other hand, when the noise signal 13 (see FIG. 2) is included in the propagation signal, the noise signal detection unit 330 detects the noise signal 13, and uses the detection signal of the noise signal 13 as the arrival time difference measurement unit 350. Output to the frequency analysis unit 355.
When the detection signal of the noise signal 13 is input from the noise signal detection unit 330, the frequency analysis unit 355 determines that point in time as the detection of the noise signal 13, and analyzes the frequency of the propagation signal at that point. Here, it is assumed that the frequency at the time of detection of the noise signal 13 is “Ft3”. This frequency Ft3 represents the frequency at the time when the second measuring device 300c receives the noise signal 13.
The frequency analysis unit 355 outputs the frequency Ft3 to the arrival time difference specifying unit 357.
The arrival time difference specifying unit 357 stores the frequency Ft3 in a storage unit (not shown).

  Thereafter, the arrival time difference specifying unit 357 reads out the frequency Ft2 and the frequency Ft3 from a storage unit (not shown), and refers to the frequency corresponding time information stored in advance in the frequency corresponding time information storage unit 356, to the frequency Ft2. A corresponding time T2 (see FIG. 9) and a time T3 (see FIG. 9) corresponding to the frequency Ft3 are determined.

  For example, it is assumed that the frequency Ft2 shown in FIG. 9 is “500 Hz”, the time T2 is “2 μs”, the frequency Ft3 is “1000 Hz”, and the time T3 is “4 μs”. In this case, the arrival time difference specifying unit 357 calculates “2 μs” as the time T2 corresponding to the frequency Ft2 and “4 μs” as the time T3 corresponding to the frequency Ft3.

  The arrival time difference specifying unit 357 determines (calculates) a time (T3−T2) obtained by subtracting the time T2 from the time T3 after calculating the time T2 and the time T3. This time (T3-T2) represents the time required for the second measuring device 300c to receive the noise signal 13 after receiving the electric signal 12 (frequency fluctuation wave) (that is, the arrival time difference Δts). .

  When the arrival time difference specifying unit 357 specifies the time (T3-T2), the specified time (T3-T2) is output to the arrival time difference notification signal generation unit 361 of the arrival time difference notification unit 360 as the arrival time difference Δts. In the second measuring device 300c, the arrival time difference notification signal generating unit 361 of the arrival time difference notification unit 360 generates the arrival time difference notification signal, and the transmission unit 370 10, an arrival time difference notification signal is transmitted.

  Hereinafter, the 1st measuring device 200c operate | moves similarly to the 1st measuring device 200a of Embodiment 1, and locates a ground fault position.

  As described above, according to the third embodiment, the time is synchronized between the first measuring device 200 and the second measuring device 300 from the first measuring device 200 and the second measuring device 300 as in the first embodiment. Therefore, the structure of the first measuring device and the second measuring device can be simplified and miniaturized.

  Moreover, according to the second measuring device 300c according to the third embodiment, the clock unit 340 is deleted and the configuration is simplified compared to the second measuring device 300a according to the first embodiment. Occurrence can be suppressed.

[Embodiment 4]
The fourth embodiment is for avoiding a case where the operator may miss the occurrence of a ground fault.

  Hereinafter, the configuration and operation of the ground fault location system according to the fourth embodiment will be described with reference to FIG. FIG. 10 is a configuration diagram of the ground fault location system according to the fourth embodiment.

In the fourth embodiment, as shown in FIG. 10, a ground fault detection relay 400 is combined with the ground fault location system 100 of the first embodiment.
The ground fault detection relay 400 is a device that detects the occurrence of a ground fault. The ground fault detection relay 400 is installed on the first measuring device 200 side of the line 10. Since the ground fault detection relay 400 is a known device, detailed description thereof is omitted here.

In the fourth embodiment, in addition to the determination of the ground fault position by the first measuring device 200 and the second measuring device 300, the occurrence of the ground fault is also detected by the ground fault detection relay 400. Thereby, the operator can recognize reliably the presence or absence of generation | occurrence | production of a ground fault.
Therefore, in the fourth embodiment, the operator may miss the occurrence of the ground fault (for example, when the ground fault position determined by the first measuring instrument 200 is very close to the first measuring instrument 200). Even so, it is possible to avoid the operator overlooking the occurrence of the ground fault.

  As described above, according to the fourth embodiment, the time is synchronized between the first measuring device 200 and the second measuring device 300 from the first measuring device 200 and the second measuring device 300 as in the first embodiment. Therefore, the structure of the first measuring device and the second measuring device can be simplified and miniaturized.

  In addition, according to the fourth embodiment, even when the operator may miss the occurrence of the ground fault, the operator can avoid missing the occurrence of the ground fault. The reliability of the orientation system 100 can be improved.

The present invention is not limited to the above-described embodiment, and various changes and modifications can be made without departing from the gist of the present invention.
For example, the second measuring device 300 may be configured to include a display unit for displaying the measured arrival time difference Δts.
For example, the ground fault detection relay 400 according to the fourth embodiment may be combined with the first measuring device 200 and the second measuring device 300 according to the second or third embodiment.

10 Power supply line (line)
DESCRIPTION OF SYMBOLS 12 Electric signal 13 Noise signal which advances to the 2nd measuring device side from a ground fault position 14 Noise signal which advances to the 1st measuring device side from a ground fault position 200 (200a, 200c) 1st measuring device 205 Clock part 210 Electric signal generation Unit 211 pulse signal generation unit 212 frequency fluctuation wave generation unit 215 transmission unit 225 reception unit 260 noise signal detection unit 265 total time measurement unit 266 total time identification unit 270 arrival time difference acquisition unit 271 arrival time difference notification signal detection unit 272 input unit 275 ground Engagement position arrival time specifying unit 280 Ground fault position locating unit 285 Display unit 300 (300a, 300b, 300c) Second measuring device 310 Receiving unit 320 Electric signal detecting unit 321 Pulse signal detecting unit 330 Noise signal detecting unit 340 Clock unit 350 Reaching Time difference measurement unit 351 Pulse signal reception time determination unit 352 Noise signal reception time determination unit 353, 357 arrival time difference identification unit 354 timer 355 frequency analysis unit 356 frequency corresponding time information storage unit 360 arrival time difference notification unit 361 arrival time difference notification signal generation unit 370 transmission unit 400 ground fault detection relay Xs first measurement Distance from vessel to ground fault position (ground fault position)
Δts Time difference between the arrival time of the electrical signal and the arrival time of the noise signal at the second measuring device ts Generation time of the noise signal at the ground fault position (ground fault time)
t0 Electric signal transmission start time at the first measuring instrument t1 Noise signal virtual transmission time at the first measuring instrument t2 Electric signal reception starting time at the second measuring instrument t3 Noise signal reception at the second measuring instrument Time t4 Noise signal reception time at the first measuring instrument

Claims (13)

Ground fault position locating method for locating a ground fault occurring in the power supply line using a first measuring instrument installed on one end of the power supply line and a second measuring instrument installed on the other end. In
The first measuring device generates a predetermined electric signal and transmits the electric signal to the second measuring device via the power supply line,
The second measuring device measures the time required for the second measuring device to receive the noise signal generated by the ground fault after receiving the electric signal as an arrival time difference,
The first measuring device measures the time taken from when the first measuring device transmits the electrical signal until it receives the noise signal as an overall time, and the first measuring device measures the time measured by the second measuring device. The arrival time difference is obtained, and further, the distance from the first measuring instrument to the position of the ground fault is Xs, the arrival time difference is Δts, the total time is T, and the speed of the signal propagating through the power supply line Is a ground fault position locating method, wherein the position of the ground fault is determined by the following formula (1).
Xs = C × (T−Δts) / 2 (1) In the ground fault location method of Claim 1,
The ground fault position locating method, wherein the first measuring device generates the electrical signal as a sinusoidal pulse signal. In the ground fault location method of Claim 1,
The ground fault location method, wherein the first measuring device generates the electrical signal as a pulse signal whose frequency periodically changes in a sawtooth shape with time. In the ground fault location method according to any one of claims 1 to 3,
The first measuring device acquires the arrival time difference by receiving the arrival time difference transmitted from the second measuring device to the first measuring device via the power supply line. Ground fault location method. In the ground fault location method according to any one of claims 1 to 3,
The ground fault position locating method, wherein the first measuring device acquires the arrival time difference when an input unit provided in the first measuring device receives an input of the arrival time difference by an operator. In the ground fault location method according to any one of claims 1 to 5,
Furthermore, using a ground fault detection relay that detects the occurrence of a ground fault,
The ground fault position locating method characterized in that the first measuring device locates the ground fault when the ground fault detection relay detects the occurrence of a ground fault on the power supply line. A ground fault position locating system that uses the first measuring instrument installed at one end of the power supply line and the second measuring instrument installed at the other end side to determine the position of the ground fault generated in the power supply line. In
The first measuring device includes:
An electrical signal generator for generating a predetermined electrical signal;
A first transmitter that transmits the electrical signal generated by the electrical signal generator to the second measuring device via the power supply line;
A first receiver for receiving a propagation signal propagating on the power supply line;
A first noise signal detection unit for detecting a noise signal generated by the ground fault according to the electrical signal from the propagation signal received by the first reception unit;
An overall time measurement unit that measures the time taken from when the first measuring device transmits the electrical signal until the noise signal is received, as an overall time;
A ground fault position locating unit for locating the position of the ground fault,
The second measuring device includes:
A second receiver that receives the propagation signal including the electrical signal and the noise signal that propagates on the power supply line;
A second noise signal detector for detecting the noise signal from the propagation signals received by the second receiver;
An arrival time difference measuring unit that measures the time required from when the second measuring device receives the electrical signal until the noise signal is received as an arrival time difference; and
The ground fault location unit of the first measuring device acquires the arrival time difference measured by the arrival time difference measuring unit of the second measuring device, and further from the first measuring device to the position of the ground fault. Where Xs is Xs, the arrival time difference is Δts, the total time is T, and the speed of a signal propagating through the power supply line is C, the position of the ground fault is expressed by the following equation (1). A ground fault position locating system characterized by locating
Xs = C × (T−Δts) / 2 (1) In the ground fault location system according to claim 7,
The overall time measuring unit of the first measuring device includes a first clock unit that measures time,
The arrival time difference measurement unit of the second measurement unit includes a second clock unit that measures time,
The electrical signal generation unit of the first measuring device generates the electrical signal as a sinusoidal pulse signal according to the time measured by the first clock unit, and
The arrival time difference measurement unit of the second measurement unit measures the reception time of the pulse signal and the reception time of the noise signal based on the time measured by the second clock unit, and the reception time of the noise signal The ground fault position locating system characterized in that the arrival time difference is measured by subtracting the reception time of the pulse signal from. In the ground fault location system according to claim 7,
The overall time measuring unit of the first measuring device includes a first clock unit that measures time,
The arrival time difference measurement unit of the second measurement unit includes a timer unit for measuring time,
The electrical signal generation unit of the first measuring device generates the electrical signal as a sinusoidal pulse signal according to the time measured by the first clock unit, and
The arrival time difference measurement unit of the second measurement unit measures the arrival time difference when the timer unit starts measuring time when receiving the pulse signal and ends measuring time when receiving the noise signal. A ground fault location system characterized by In the ground fault location system according to claim 7,
The overall time measuring unit of the first measuring device includes a first clock unit that measures time,
The arrival time difference measurement unit of the second measurement unit includes a frequency analysis unit that analyzes the frequency of the signal,
The electrical signal generator of the first measuring device generates the electrical signal as a pulse signal whose frequency periodically varies in a sawtooth shape with time according to the time measured by the first clock unit. ,And,
The arrival time difference measurement unit of the second measurement unit detects the frequency at the time of reception of the pulse signal and the frequency at the time of reception of the noise signal by the frequency analysis unit, A ground fault position locating system characterized in that the difference in arrival time is measured by specifying a time corresponding to a change amount between frequencies. In the ground fault location system according to any one of claims 7 to 10,
The second measuring device further includes a second transmitting unit that transmits the arrival time difference measured by the arrival time difference measuring unit to the first measuring device via the power supply line.
In the first measuring device, the first receiving unit receives the arrival time difference transmitted from the second measuring device to the first measuring device via the power supply line, thereby calculating the arrival time difference. A ground fault location system characterized by acquisition. In the ground fault location system according to any one of claims 7 to 10,
The first measuring device further includes an input unit that is operated by an operator to input information;
The ground fault location system, wherein the first measuring device acquires the arrival time difference when the input unit receives the arrival time difference input by the operator. In the ground fault location system according to any one of claims 7 to 12,
The ground fault position locating system further comprising a ground fault detection relay for detecting occurrence of a ground fault on the power supply line.

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