JPH04331418A - Method and device for detecting grounded section of distribution line - Google Patents

Abstract

PURPOSE:To know a grounded section of a distribution line with less number of voltage sensors than before by finding a phase difference between a zero phase current and a phase of a line voltage between the specified two phases which is detected at a measuring point located at the end of each section of the distribution line. CONSTITUTION:A terminal station T1 detects an earth current of one direction and a terminal station T2 detects an earth current of the opposite direction. An element having a phase common to the terminal stations T1 and T2, for example, a line voltage between the specified two phases or a phase voltage of the specified one phase is taken and a phase difference between a zero-phase current and the said element is calculated and the result is sent to a master station. Based on a distribution of a phase difference from the zero-phase current, one of the data received from each terminal station, the master station decides a grounded section of the distribution line.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention detects directional ground fault information by measuring the voltage and current of the distribution line at terminal stations installed in certain sections on the distribution line, and detects ground fault fault sections of the distribution line. The present invention relates to a method and device for detecting a ground fault section of a power distribution line.

0002

2. Description of the Related Art A power distribution line is an electric line installed between a substation and a consumer, and a large number of power distribution lines are supplied from one substation. In addition to circuit breakers, each distribution line is provided with section switches at regular intervals. When an accident such as a ground fault occurs in the middle of a distribution line, the circuit breaker is opened and the sectional switch is also opened accordingly to protect the distribution line. In order to supply power to areas other than the faulted area, it is important to detect which area has the ground fault fault.

[0003] Therefore, in the past, terminal stations (which may be installed at the same location as the section switches or at a different location) are installed at regular intervals along the distribution line. ). This terminal station is
It has three current sensors that measure each phase current and three voltage sensors that measure each phase voltage.The zero-sequence current I0 is calculated from the three current sensors, and the zero-sequence voltage V0 is calculated from the three voltage sensors. Calculate "Zero-sequence current I0 and zero-sequence voltage V
0 has occurred, and calculate the phase difference between the zero-sequence current I0 and the zero-sequence voltage V0, determine ground fault information and directional ground fault information in the terminal station, and transmit it to the master station, The master station determined that the section located between the terminal station that detected the ground fault in the direction of the substation and the terminal station that detected the ground fault in the direction of the load was the ground fault fault section.

0004

[Problem to be Solved by the Invention] The terminal station described above requires three voltage sensors, but these voltage sensors are required to be attached directly to the normally installed power distribution line and optically measure the voltage between them and the ground. A type of measurement is used. However, since we are measuring high voltage (e.g. 6.6kV),
The drawback is that it is greatly affected by the insulation resistance with the ground. For example, if the insulation resistance with the ground changes due to weather or dirt on the surface of the voltage sensor, the phase angle of the measured voltage may deviate from the phase angle of the actual voltage, or an error may occur in the magnitude of the measured voltage itself.

[0005] Therefore, if the voltage sensor is constituted by a transformer PT and built into the terminal station, the above-mentioned drawbacks will not occur, but in order to detect the zero-sequence voltage V0, three expensive transformers PT must be installed. There's a problem. A large number of terminal stations are placed on each distribution line, and considering the large number of distribution lines, it is preferable to make the configuration of the terminal station as simple as possible.
It is better to keep the number as small as possible.

[0006] An object of the present invention is to solve the above-mentioned technical problems, and by arranging terminal stations that use fewer voltage sensors than in the past, it is possible to know the faulty section of a power distribution line due to a ground fault. An object of the present invention is to provide a method and apparatus for detecting a faulty section of a power distribution line.

[0007]

[Means for Solving the Problems] A method for detecting a ground fault fault section of a power distribution line according to claim 1 for achieving the above object includes the following steps:
Divide the distribution line into multiple sections, detect each phase current of the distribution line at the measurement point at the end of each section, calculate the zero-sequence current based on these detected currents, and calculate the zero-sequence current and the current at the measurement point. Calculate the phase difference between the obtained line voltage between two predetermined phases of the distribution line, find the distribution of the calculated phase difference at each measurement point along the distribution line, and measure the phase difference by approximately 180°. This method determines the section that exists between the points as the ground fault section.

[0008] The method for detecting a ground fault fault section of a distribution line according to claim 2 divides the distribution line into a plurality of sections, and detects the phase voltage of a predetermined one phase of the distribution line at a measurement point at the end of each section. At the same time, each phase current of the distribution line is detected, the zero-sequence current is determined based on the detected current, the phase difference between the zero-sequence current and the detected phase voltage is calculated, and each measurement point is measured along the distribution line. The distribution of the phase difference calculated in is obtained, and the phase difference is approximately 1.
This method determines the section existing between measurement points that turn 80 degrees as a ground fault section.

[0009] In order to achieve the above object, there is provided a ground fault fault section detection device for a distribution line according to claim 3, which includes a terminal station arranged in each section of a distribution line divided into a plurality of sections, and Each terminal station has a current sensor that detects each phase current of the distribution line, and calculates the zero-sequence current based on the detected current of the current sensor, and calculates the zero-sequence current. and a line voltage between two predetermined phases of the distribution line, which is the control AC power supply voltage of the terminal station, and a transmitting means for transmitting data on the phase difference detected by the calculating means. The master station is provided with a terminal station that distinguishes a group of terminal stations having a phase difference of approximately 180 degrees based on the distribution of the phase differences included in the data received from each terminal station, and A ground fault section determination means is provided for determining a section existing between mutually adjacent terminal stations in the group as a ground fault section of the distribution line.

[0010] The ground fault fault section detection device for a distribution line according to claim 4 includes a terminal station arranged in each section of a distribution line divided into a plurality of sections, and a master station for receiving data from the terminal station. Each terminal station has a voltage sensor that detects the phase voltage of one predetermined phase of the distribution line, a current sensor that detects each phase current of the distribution line, and a current sensor that detects the current of each phase of the distribution line. Calculating means for determining a phase current and calculating a phase difference between the zero-sequence current and a predetermined phase voltage of one phase detected by a voltage sensor; and a transmitting means for transmitting data on the phase difference detected by the calculating means. The master station is provided with a terminal station that distinguishes a group of terminal stations having a phase difference of approximately 180° based on the distribution of the phase differences included in the data received from each terminal station, and A ground fault section determining means is provided for determining a section existing between mutually adjacent terminal stations in the group as a ground fault section of the distribution line.

[0011] In the distribution line ground fault fault section detection device according to claim 5 or 6, the terminal station divides the omnidirectional area into at least five areas, and detects the zero-sequence current and the line voltage between two predetermined phases or the predetermined line voltage between two phases. The master station transmits the phase difference with the phase voltage of one phase as data of the region including the phase difference, and the master station groups terminal stations belonging to regions separated by one or more regions into the same terminal station group.

0012

[Operation] According to each of the inventions described in claims 1 to 4 above, when the phase difference between the zero-sequence current and the line voltage between two predetermined phases or the phase voltage of one predetermined phase is θ, When a ground fault occurs, the terminal detects the ground fault point in the direction of the power transmission end by utilizing the fact that the phase difference θ is reversed by approximately 180 degrees depending on the positional relationship between the ground fault fault point and the terminal station. A station group is distinguished from a terminal station group that detects a ground fault point in the direction opposite to the direction in which the power transmission end exists, and the section located between adjacent terminal stations among these differentiated terminal stations is defined as a distribution line. It can be determined as a ground fault section.

This will be explained in detail. FIG. 1 is a conceptual diagram of a power distribution line, and assumes that power sources Ea, Eb, and Ec exist at the power transmission end. Terminal stations installed adjacent to each other are indicated as T1 and T2. Assume that a ground fault has occurred between terminal stations T1 and T2, and that the ground fault resistance is Rg. C1 and C2 are
These are the ground capacity of the distribution line on the power supply side and load side of the ground fault point, respectively.

[0014] When a ground fault occurs, the zero-sequence voltage V0 at the ground fault point is expressed as V0 = -Ea/(1+3jωCRg). Here, C=C1 +C2. Furthermore, the zero-sequence current I0 detected at the terminal station T1 is I0 = C1 Ig/3C
(1
) What is detected at terminal station T2 is I0 = -C2 Ig/3C
(2)
It is. Here, Ig=3jωCEa/(1+3jωCRg).

From equations (1) and (2) above, it can be seen that terminal station T1 and terminal station T2 detect ground fault currents in opposite directions. Therefore, an element having a common phase between the terminal station T1 and the terminal station T2, for example, the line voltage between two predetermined phases or the phase voltage of one predetermined phase, is taken and the relative phase difference between it and the zero-sequence current is calculated. , to the master station, the master station detects a ground fault in the direction of the power transmission end based on the distribution of the phase difference with the zero-sequence current included in the data received from each terminal station. It is possible to distinguish between a terminal station group that detects a ground fault point and a terminal station group that detects a ground fault point in the direction opposite to the direction in which the power transmission end exists. The section where the ground fault occurs can be determined as the section where the distribution line has a ground fault.

In the invention described in claim 5 or 6, since all directions are divided into at least five regions, the phase difference between the zero-sequence current and the line voltage between two predetermined phases or the phase voltage of one predetermined phase is There is no need to send the data as is, and only the data that specifies the area needs to be sent.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples will be explained in detail below with reference to the accompanying drawings showing examples. FIG. 2 is a power distribution system diagram, and the distribution substation 1 is equipped with a transformer 11 with a Δ-Δ connection.
1, the power stepped down to 6.6kV is transferred to circuit breakers 3a and 3.
It is supplied to the distribution lines 4a, 4b, . . . through b, . The distribution lines 4a, 4b, . . . are equipped with Y-Y connected transformers 5a1 for distributing power to consumers.
, 5a2, ..., 5b1, 5b2, ... are connected, and terminal stations 7a1, 7a2, ..., 7b1, 7b2, ... are connected near each transformer 5a1, 5a2, ...・・・
・ is provided.

Each terminal station 7a1, 7a2, . . . has the same configuration, and CT1, CT detecting the current of each phase
2, each phase current information taken out from CT3 and the line voltage information between the ab phases taken out from the transformers 5a1, 5a2, etc. (this line voltage between the ab phases is used for the driving power source of the terminal station) It is not necessary to install a new voltage sensor). An arithmetic processing unit 71 that calculates the phase difference θ, etc. and determines whether there is a ground fault, short circuit, or disconnection, and the judgment result obtained by the arithmetic processing unit 71 is converted into 4-bit data and transmitted to the master station 9 (see FIG. 8). The transmitter 72 is provided with a transmitter 72 for transmitting data.

As shown in FIG. 3, the arithmetic processing unit 71 includes an addition circuit 716 that calculates the value of the zero-phase current, and an a-phase current Ia.
A sample hold circuit 711 that samples the value of
, a sample-and-hold circuit 712 that samples the value of the b-phase current Ib, a sample-and-hold circuit 713 that samples the value of the c-phase current Ic, and a sample-and-hold circuit 7 that samples the value of the zero-sequence current I0.
14 and a sample hold circuit 715 that samples the value of the line voltage Vab, a multiplexer 720 that sends out the sampled and held values in chronological order, and a conversion circuit that A/D converts the data output from the multiplexer 720. Circuit 730 and A/D
The converted data is digitally calculated to calculate the line voltage Vab.
, the magnitude and phase angle of each phase current Ia, Ib, Ic, zero-sequence current I0, positive-sequence current I1, negative-sequence current I2, and the phase difference θ between line voltage Vab and zero-sequence current I0, Negative sequence current I2 relative to the magnitude of positive sequence current I1
Calculation circuit 74 that calculates the ratio I2/I1 of the size of
0 and a determination circuit 750 that determines whether there is a ground fault, short circuit, or disconnection based on the calculation data of the calculation circuit 740.

Furthermore, the arithmetic processing unit 71 calculates the line voltage Va
A fundamental wave pulse generation circuit 760 that generates a fundamental wave pulse every cycle of b, and a frequency divider 7 that divides the frequency of the pulse thus generated by a predetermined frequency division ratio (for example, 1/12 times).
61, and a finer frequency division ratio (for example, 1/6
A frequency divider 762 that divides the frequency by
switching controller 76 providing switching control signals to 715;
3, and the calculation circuit 740 performs calculation processing using the output pulse of the frequency divider 761 as a synchronization signal.

The calculation circuit 740 can use any conventionally known method to calculate the magnitude and phase angle of the current or voltage. For example, the magnitude can be determined by determining a Fourier sine component and a Fourier cosine component over one period and taking the root mean of both components. Further, the phase angle can be determined by taking the ratio tan-1 of the Fourier sine component and the Fourier cosine component.

FIG. 4 is a flowchart showing the procedure for determining ground faults, short circuits, and disconnections performed by the determination circuit 750. Figure 4
According to , the determination circuit 750 performs a short circuit determination (step (1)) based on various data supplied from the calculation circuit 740 , and if it is determined that there is a short circuit, it sends a code "0001" representing a short circuit to the transmitter 72 . Send to. If it is determined that there is no short circuit, a disconnection determination (step (2)) is performed.
If it is determined that the wire is broken, a code "0010" representing the wire breakage is sent.

If it is determined that there is no disconnection, it is determined that there is a ground fault (
Perform steps (3) (4)). Step (3)
Now, the zero-sequence current I0 is compared with the threshold value Ix, and the zero-sequence current I0 is
0 exceeds the threshold Ix, in step (4) the phase difference θ between the line voltage Vab and the zero-sequence current I0 is
Regions I, II, ..., VII divided into 8 equal parts of 360°
I (see Figure 5) is determined, and step (
7) Send the corresponding code in . For example, 0<θ
If ≦π/4, the signal falls into region I, so the code "1000" is sent. If π/4<θ≦π/2, the signal falls into region II, so the code “1001” is transmitted. Note that the ground fault determination in steps (3) and (4) means a one-wire ground fault, and in the case of a two-wire or three-wire ground fault, step (1) is used.
This can be determined by short circuit determination, so step (3)
(4) There is no way to determine a 2-wire ground fault or a 3-wire ground fault.

[0024] If it is determined that there is no ground fault, step (8)
The code "0000" indicating no failure is sent out. The transmitter 72 transmits the code received from the determination circuit 750 to the master station 9 through a medium such as wireless, optical, or infrared rays.
Step (9)). The master station 9 consists of a receiving section 91 and a failure section determining section 92, as shown in FIG.

The short circuit determination in step (1) is shown in FIG.
As shown in FIG. 1, the determination is made based on whether any of the phase currents Ia, Ib, and Ic exceeds a reference current (for example, 1.2 times the rated current). In FIG. 6, the reference current is shown as 480A (rated current is 400A). The disconnection determination in step (2) is as shown in Figure 7: 1 wire disconnection, 2 wire disconnection,
Disconnection of the three wires is determined separately, and when any type of disconnection occurs, it is determined as a "disconnection."

One wire breakage occurs when any of the phase currents Ia, Ib, and Ic exceeds 1% of the rated current, the line voltage Vab exceeds approximately 80% of the phase voltage, and the positive-sequence current I1 and the negative-sequence current I2
The determination is made when the ratio I2/I1 of the magnitude exceeds 0.6 times. In Figure 7, "1% of rated current" is 4A
, about 80% of the "phase voltage" is displayed at 3000V. The number 0.6 times is determined empirically.

Two-wire disconnection occurs when the phase currents Ia, Ib, and Ic are all less than 1% of the rated current, and the line voltage Va
b is determined when it falls within a range of about 1% to about 2.5% of the phase voltage. 3-wire disconnection is caused by each phase current Ia, Ib,
It is determined that Ic is all less than 0.1% of the rated current and the line voltage Vab is less than about 1% of the phase voltage.

The failure section determination section 92 of the master station 9 determines in which section there is a ground fault, short circuit, or disconnection based on the code received from the transmission section 72 of each terminal through a medium such as radio, light, or infrared rays. do. The method for this determination is as follows. Terminal station 7 along the distribution line as shown in Figure 9.
Assume that a1, . . . , 7a6 are arranged.

When a one-wire ground fault occurs between the terminal station 7a3 and the terminal station 7a4 (see FIG. 9(a)), the power is sent from the terminal stations 7a1, 7a2, and 7a3 on the power transmission side from the ground fault point. The regions showing the phase difference θ between the line voltage Vab and the zero-sequence current I0 are the same region or two regions adjacent to each other (for example, regions I and VIII in FIG. 5). However, terminal stations 7a4, 7a5, on the load side from the ground fault point
Line voltage Vab and zero-sequence current I0 sent from 7a6
The region showing a phase difference θ with
These are the regions (regions V and IV in FIG. 5) that are shifted by degrees. Therefore, the master station 9 knows that a ground fault has occurred between the terminal station 7a3 and the terminal station 7a4 before and after the region of phase difference deviates greatly.

Next, when a short circuit failure occurs between the terminal stations 7a3 and 7a4 (see FIG. 9(b)), the power is sent from the terminal stations 7a1, 7a2, and 7a3 on the power transmission side from the failure point. The information sent from the terminal stations 7a4, 7a5, and 7a6 located on the load side of the failure point is "short circuit" information, whereas the information sent from the terminal stations 7a4, 7a5, and 7a6 on the load side from the failure point is "broken wire" (in the case of a two-wire short circuit) or "no failure". ” (in case of 3-wire short circuit). Therefore, in the master station 9, it becomes clear that a short circuit failure has occurred between the terminal station 7a3 and the terminal station 7a4.

Next, when a disconnection fault occurs between the terminal station 7a3 and the terminal station 7a4 (see FIG. 9(c)), the power is sent from the terminal stations 7a1, 7a2, and 7a3 on the power transmission side from the fault point. The information coming from the terminal station 7a4, 7a5, 7 located on the load side from the failure point is "no failure" information.
The information sent from a6 is "disconnection" information. Therefore, the master station 9 knows that a disconnection fault has occurred between the terminal station 7a3 and the terminal station 7a4.

Although the present invention has been described above based on examples, the present invention is not limited to the above-mentioned examples. In the embodiment described above, the line voltage Vab between the ab and phase was used, but a single phase voltage (for example, the a phase voltage Va) may be used. In this case, since the existing voltage sensor cannot be used, it is necessary to provide one dedicated voltage sensor, but there is an advantage that the configuration is simpler than the conventional one, which required three.

In addition to the circuit shown in FIG. 7, it is also possible to use a circuit as shown in FIG. 10 as the circuit for determining whether one wire is disconnected. In the circuit of FIG. 10, each phase current Ia, I
The determination is made when either b or Ic is less than 1% of the rated current and the line voltage Vab exceeds about 80% of the phase voltage. It is also possible to use the circuit of FIG. Figure 1
In circuit 1, one of the phase currents Ia, Ib, and Ic is less than 1% of the rated current, and the remaining two are 1% or more of the rated current, and
The line voltage Vab exceeds approximately 80% of the phase voltage, and the positive sequence current I
1 and the magnitude of the negative sequence current I2, I2/I1, is 0.
．． Judgment will be made when it exceeds 6 times. If the circuit shown in FIG. 11 is used, if a short-circuit failure occurs, all information sent from the terminal station on the load side of the failure point will be "no failure" information.

Also, according to FIG. 5, all directions are divided into eight areas, but it is practical if the omnidirectional area is divided into at least five areas (if divided into four areas, as shown in FIG. As shown in Figure 2, the phase angle data occupies the entire area, making it impossible to identify the ground fault section). Various other changes can be made without departing from the gist of the invention.

[0035]

As described above, according to the invention of the method for detecting a ground fault fault section of a distribution line as set forth in claim 1, the line between the predetermined two phases detected at the measurement point at the end of each section of the distribution line. Using the phase of the voltage as a reference, the phase difference with the zero-sequence current is determined, and the ground fault point can be easily detected from the distribution of the phase difference over each measurement point.

According to the invention of the method for detecting a ground fault fault section of a distribution line according to claim 2, a predetermined phase voltage of one phase is detected at the measurement point at the end of each section of the distribution line, and the detected predetermined phase voltage is detected. 1
The phase difference with the zero-sequence current is determined using the phase of the phase voltage of the phase as a reference, and the ground fault point can be easily detected from the distribution of the phase difference over each measurement point. According to the invention of the ground fault fault section detection device of a power distribution line according to claim 3, if each terminal station detects the phase difference between the zero-sequence current and the line voltage and transmits it to the master station, The station can determine the ground fault section of the distribution line based on the distribution of phase differences sent from each terminal station. In this case, the terminal station uses a predetermined voltage of 2 on the distribution line, which is the AC power supply voltage for control of the terminal station.
Since the line voltage between phases is used, compared to the conventional method of measuring three-wire voltage, the configuration of the terminal station is simpler and costs can be lowered, and many terminal stations can be arranged. This is particularly advantageous when

[0037] According to the invention of the ground fault fault section detection device of a distribution line as set forth in claim 4, if each terminal station detects the phase difference between the zero-sequence current and the phase voltage and transmits it to the master station. ,
The master station can determine the ground fault section of the distribution line based on the distribution of phase differences sent from each terminal station. In this case, it is only necessary to measure one phase voltage at the measurement point, which simplifies the configuration of the terminal station and reduces costs compared to the conventional method of measuring three-wire voltage. This is especially advantageous when a large number of terminal stations are installed.

[0038] According to the invention of the ground fault fault section detection device of the distribution line according to claims 5 and 6, since the omnidirectional area is divided into at least five areas, the transmission line between the terminal station and the master station has a phase angle. It is sufficient to send data indicating which of these five areas the device falls into. Therefore, it is not necessary to send the phase angle data as is, and it is possible to prevent the capacity of the transmission line from increasing. Furthermore, if the capacity of the transmission line is fixed, the capacity allocated to other data can be increased.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram of a power distribution line in which a ground fault has occurred, for explaining the principle of the present invention.

FIG. 2 is a power distribution system diagram in which terminal stations are arranged.

FIG. 3 is a block diagram showing the internal configuration of an arithmetic processing unit provided in the terminal station.

FIG. 4 is a flowchart showing the procedure for determining ground faults, short circuits, and disconnections performed by the determination circuit 750.

FIG. 5 is a diagram in which all directions are divided into eight regions for classifying phase angles.

FIG. 6 is a logic circuit diagram for determining a short circuit.

FIG. 7 is a logic circuit diagram for determining disconnection.

FIG. 8 is a block diagram showing the main part configuration of a master station.

FIG. 9 is a distribution line diagram for explaining a method for determining a ground fault section of a distribution line.

FIG. 10 is a logic circuit diagram showing another embodiment that performs one-line disconnection determination.

FIG. 11 is a logic circuit diagram showing still another embodiment for determining one-line disconnection.

FIG. 12 is a diagram in which all directions are divided into four regions.

[Explanation of symbols]

4a, 4b Distribution lines 7a1, 7a2, 7b1, 7b1 Terminal station 72 Transmission section 740 Calculation circuit 9 Master station 92 Ground fault fault section determining section I to VIII Regions CT1, CT2, CT3 Current sensors T1, T2
terminal station

Claims (6)

[Claims] Claim 1: A method for detecting a ground fault fault section of a power distribution line when a ground fault fault occurs in the power distribution line, wherein the power distribution line is divided into a plurality of sections, and the distribution line is detected at a measurement point at the end of each section. Detects each phase current of The distribution of the phase difference calculated at each measurement point along the distribution line is obtained, and the section existing between the measurement points where the phase difference changes approximately 180 degrees is determined as the ground fault section. A method for detecting ground fault fault sections in distribution lines. Claim 2: A method for detecting a ground fault section of a distribution line when a ground fault occurs in the distribution line, the distribution line being divided into a plurality of sections, and measuring points at the ends of each section. At the same time as detecting the phase voltage of one predetermined phase of the electric wire, each phase current of the distribution line is detected, the zero-sequence current is determined based on these detected currents, and the difference between the zero-sequence current and the detected phase voltage is calculated. Calculate the phase difference, find the distribution of the calculated phase difference at each measurement point along the distribution line, and determine the area between the measurement points where the phase difference changes approximately 180 degrees as the ground fault area. A method for detecting a ground fault fault section of a power distribution line. 3. A ground fault fault section detection device for a distribution line that detects a ground fault fault section when a ground fault occurs in a distribution line, the device comprising: a terminal station located in each section of a distribution line divided into a plurality of sections; Each terminal station is equipped with a current sensor that detects each phase current of the distribution line, and a zero-sequence current is determined based on the current detected by the current sensor. Calculating means for calculating a phase difference between the voltage and the line voltage between two predetermined phases of the distribution line, and a transmitting means for transmitting data of the phase difference detected by the calculating means, further comprising:
arranging a master station for receiving data from the terminal station;
This master station has a phase difference of approximately 180 degrees based on the distribution of the phase differences included in the data received from each terminal station.
Ground fault fault section determining means is provided for distinguishing between different terminal station groups and determining a section existing between mutually adjacent terminal stations among these differentiated terminal station groups as a ground fault fault section of the distribution line. A ground fault fault section detection device for a power distribution line, characterized in that: 4. A ground fault fault section detection device for a distribution line, which detects a ground fault fault section when a ground fault fault occurs in a distribution line, wherein a terminal station is provided in each section of a distribution line divided into a plurality of sections. Each terminal station is equipped with a voltage sensor that detects the phase voltage of one predetermined phase of the distribution line, a current sensor that detects the current of each phase of the distribution line, and a zero-phase sensor that detects the current of each phase of the distribution line. Calculating means for determining a current and calculating a phase difference between the zero-phase current and a predetermined phase voltage of one phase detected by a voltage sensor; and a transmitting means for transmitting data on the phase difference detected by the calculating means. Further, a master station for receiving data from the terminal stations is arranged, and the master station calculates the phase difference based on the distribution of the phase differences included in the data received from each terminal station. Ground fault fault section determining means distinguishes between terminal station groups that differ by approximately 180°, and determines a section existing between mutually adjacent terminal stations among the differentiated terminal station groups as a ground fault fault section of a power distribution line. What is claimed is: 1. A ground fault fault section detection device for a power distribution line. 5. The terminal station divides the omnidirectional region into at least five regions, and transmits the phase difference between the zero-sequence current and the line voltage between two predetermined phases as data for the region including the phase difference,
4. The ground fault fault section detection device for a power distribution line according to claim 3, wherein the master station groups terminal stations belonging to one or more areas apart from each other into the same terminal station group. 6. The terminal station divides the omnidirectional region into at least five regions, transmits the phase difference between the zero-sequence current and the predetermined one-phase phase voltage as data of the region including the phase difference, and 5. The ground fault fault section detection device for a power distribution line according to claim 4, wherein the station groups terminal stations belonging to one or more areas apart from each other into the same terminal station group.