JPH04347532A - Method and device for detecting disconnected section of distribution line - Google Patents

Abstract

PURPOSE:To determine a disconnected section of a distribution line without requiring a voltage sensor by measuring the current of the distribution line at a terminal station located for every predetermined section on the distribution line. CONSTITUTION:A distribution line is divided into a plurality of sections and phase currents Ia, Ib, Ic are detected at a measuring point in each section. Positive-phase current I1 and negative-phase current I2 are then calculated based on thus detected currents. When the line voltage Vij is higher than a threshold Vth, any one of the currents Ia, Ib, Ic is larger than thresholds Iax, Iby, Icz and the ratio I2/I1 exceeds a threshold k0, a decision is made that the measuring point is closer to the load side than the disconnection point thus determining the disconnected section. Consequently, disconnection fault point can be determined easily and reliably.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention provides a power distribution system that can detect disconnection information by measuring the current in the distribution line at terminal stations installed at certain intervals on the distribution line. The present invention relates to a method and apparatus for detecting a disconnection section of an electric wire.

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 disconnection 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. It is important to determine where the disconnected section is in order to supply power to the area.

[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 Ia, Ib, Ic and three voltage sensors that measure each phase voltage Va, Vb, Vc.
, calculates the positive sequence current I1 and negative sequence current I2, calculates the zero sequence voltage V0, positive sequence voltage V1 and negative sequence voltage V2 from the three voltage sensors, and generates disconnection information in the terminal station based on these currents and voltages. is collected and sent to the master station,
The master station considered the section located between the terminal station that detected the disconnection and the terminal station that did not detect the disconnection to be the disconnection section (
(Refer to Japanese Patent Application Laid-open No. 2-266822).

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] Therefore, there are also known methods of detecting wire breakage using only current information, and some of these methods are also described in the above-mentioned publication (Japanese Patent Laid-Open No. 2-266822). for example,
This method detects a disconnection based on the fact that the magnitude of the positive-sequence current I1 and the magnitude of the negative-sequence current I2 are equal. According to this method, even in the case of a two-wire short circuit, the magnitude of the positive-sequence current I1 and the magnitude of the negative-sequence current I2 are equal. Since the sizes are the same, it is determined that the wire is broken. Therefore, there is a need for a determination method that can detect only disconnections.

An object of the present invention is to solve the above-mentioned technical problems and to provide a method for determining a disconnection section of a distribution line, which can determine the disconnection section of a distribution line without installing a voltage sensor compared to the conventional method. The purpose is to provide equipment.

[0008]

[Means for Solving the Problems] A method for detecting a disconnection section of a distribution line according to claim 1 to achieve the above object divides the distribution line into a plurality of sections, and measures each section of the distribution line at a measurement point in each section. Detect phase currents Ia, Ib, and Ic, calculate positive-sequence current I1 and negative-sequence current I2 based on these detected currents, and set the magnitude of each phase current Ia, Ib, and Ic to the rated current of the distribution line. Threshold Iax set based on
, Iby, Icz, and the ratio I2 /I1 of the magnitude of the positive sequence current I1 and the magnitude of the negative sequence current I2 is
The magnitude of the line voltage Vij between two predetermined phases of the distribution line obtained at the measurement point is determined based on the rated line voltage by comparing it with a threshold value k0 set to 0.5 or more and less than 1. This is a method of determining a disconnection section by comparing it with a threshold value Vth.

For example, in order to detect a single wire disconnection, the magnitude of the line voltage Vij is greater than the threshold value Vth, and the magnitude of any one of the phase currents Ia, Ib, and Ic is greater than the threshold value Ia.
x, Iby, Icz, and the ratio I2/
When I1 exceeds the threshold value k0, the measurement point is considered to be on the load side from the disconnection point, and the disconnection section can be determined. To detect a two-wire disconnection, the line voltage Vi
If the magnitude of j is within the range determined by the thresholds Vth1 and Vth2, and the magnitudes of the phase currents Ia, Ib, and Ic are all smaller than the thresholds Iax, Iby, and Icz, the measurement point has a higher load than the disconnection point. Assuming that it is on the side,
The disconnection section can be determined. To detect a three-wire disconnection, if the line voltage Vij is smaller than the threshold Vth and the phase currents Ia, Ib, and Ic are all smaller than the thresholds Iax, Iby, and Icz, then The disconnection section can be determined by assuming that the measurement point is on the load side from the disconnection point.

[0010] In order to achieve the above object, the disconnection section detection device for a power distribution line according to claim 2 includes disposing a terminal station in each section of a distribution line divided into a plurality of sections, and receiving data from the terminal station. Each terminal station is equipped with a current sensor that detects each phase current Ia, Ib, and Ic of the distribution line, and a predetermined voltage of the distribution line that is the control AC power voltage of the terminal station. Voltage comparison means for comparing the magnitude of the inter-phase line voltage Vij with a threshold value Vth set based on the rated line voltage, and a positive sequence current I1 based on the detected current of the current sensor.
and a calculation means for calculating the negative phase current I2, and threshold values Iax, Iby, which are set based on the rated current of the distribution line, respectively, to determine the magnitude of each phase current Ia, Ib, Ic.
A first current comparison means for comparing with Icz and a positive sequence current I1
and the magnitude of the negative sequence current I2 I2 /I
1, the threshold value k0 is set to 0.5 or more and less than 1.
and a second current comparing means for comparing the wire breakage with a second current comparing means, and a transmitting means for transmitting the data of the determination result of the disconnection determining means, and the master station is provided with data that is received from each terminal station. Based on the determination results included in the data, the terminal stations with different determination results are distinguished, and the sections that exist between adjacent terminal stations among these differentiated terminal station groups are determined as disconnected sections of the distribution line. A disconnection section determining means is provided.

[0011] Furthermore, the disconnection section detection device of a distribution line according to claim 3 is provided with a voltage comparison means, a first current comparison means, a second current comparison means, and a disconnection determination means on the master station side. .

0012

[Operation] According to the inventions recited in claims 1, 2, and 3 above, when a disconnection fault occurs in the distribution line, the magnitude of the line voltage Vij between two predetermined phases of the distribution line obtained at the measurement point is determined. and the threshold value Vth, and each phase current Ia, Ib, Ic
is compared with the thresholds Iax, Iby, and Icz, and by utilizing the fact that the ratio between the magnitude of the negative sequence current I2 and the magnitude of the positive sequence current I1 increases beyond the threshold k0, the power transmission A group of terminal stations that detect a disconnection point in the direction in which the power transmission end exists and a group of terminal stations that detect a disconnection point in the direction opposite to the direction in which the power transmission end exists are distinguished, and among these differentiated terminal stations, terminal stations that are adjacent to each other are The section located between the lines can be determined as the disconnection section of the distribution line.

[0013] The following cases will be considered separately. FIG. 2 shows the case of a line break, and the terminal stations installed adjacent to each other on the distribution line are indicated as T1 and T2. Each terminal station T1, T2 has loads Z1ab, Z1bc, Z1ca, Z
2ab, Z2bc, and Z2ca are connected by Δ. Many loads are connected ahead of the terminal station T2, but
As a result of the synthesis, it is assumed that the loads Z1, Z2, and Z3 are connected.

Assume now that an a-phase disconnection occurs between terminal stations T1 and T2. If the voltage between bc and Vbc is Ia'
=Vbc/(Z21+Z3)-Vbc/(Z23+Z
1)={(Z23-Z21)+(Z1-Z3)}
Vbc/{(Z21+Z3)+(Z23+Z1)}
becomes. Therefore, Z23=Z21, Z1=Z3
Otherwise, the a-phase current Ia' will generally flow. In other words, due to load imbalance, terminal station T2 has a
A phase current Ia' will flow (if the load is balanced, Ia'=0).

The voltage Vab' between the ab phases is

[0016]

[Math 1]

It is expressed as follows. Applying specific numbers,
It will look like this: Z2ab, Z2bc, Z2ca =190Ω, Z1 =
1000Ω, Z2 = 190Ω, Z3 = 210Ω, Vb
c=6600V, Ia'=10.9A, Ib=20A
, Ic=30.9A At this time |I1 |=|I2 |=
44A, and |I2 |/|I1 |=1. V
ab' becomes 4032V.

FIG. 3 shows a case where two wires (b and c phases) are disconnected, and FIG. 4 is a circuit diagram equivalently converted to a Y-connection. From the circuit in Figure 4, each phase current is

[0019]

[Math 2]

It is expressed as: Applying specific numbers,
It will look like this: Za = 15Ω, Zb = 150Ω, Zc = 140Ω
, Zs = -j2650Ω (1μF), Va = 382
0V At this time, Ia = 2.87A, Ib = 1.284
A, Ic = 1.584A, Vab = 234V. Vab decreases to about 100V when the load becomes heavier. Furthermore, Vab increases as Zs decreases (as the line length increases). Typically 0.5% of line voltage
It is preferable to set it to 10%. Line voltage is 6600
If V, it is preferable that 33V<Vab<660V.

The threshold values Iax, Iby, and Icz for comparison with the magnitudes of the phase currents Ia, Ib, and Ic vary depending on the degree of load imbalance, and the larger the imbalance, the larger the threshold values Iax, Iby, and Icz need to be set. , is empirically selected to be 0.5% or more and less than 10% of the rated load current. Further, the threshold value to be compared with the ratio I2 /I1 may be a value close to 1, but a value of at least 0.5 allows detection with sufficient certainty.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples will be explained in detail below with reference to the accompanying drawings showing examples. FIG. 5 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 of the terminal stations 7a1, 7a2, .
2, each phase current Ia, Ib, I extracted from CT3
c information 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 the one used for the drive power source of the terminal station. an arithmetic processing unit 71 that calculates the line voltage Vab, zero-sequence current I0, positive-sequence current I1, and negative-sequence current I2 based on the following: The transmitting unit 72 transmits data of the determination result obtained by the arithmetic processing unit 71 to the master station 9 (see FIG. 9).

As shown in FIG. 6, the arithmetic processing unit 71 includes an addition circuit 716 that calculates the value of the zero-phase current, and an addition circuit 716 that calculates the value of the a-phase current,
An addition circuit 716 that adds the values of phase current and c-phase current, a sample-and-hold circuit 711 that samples the value of a-phase current Ia, a sample-and-hold circuit 712 that samples the value of b-phase current Ib, and c-phase current Ic.
A sample hold circuit 713 that samples the value of
, a sample-and-hold circuit 714 that samples the value of the zero-sequence current I0, and a sample-and-hold circuit 715 that samples the value of the line voltage Vab, and a multiplexer 720 that sends out the sampled and held values in chronological order, multiplexer 720
A conversion circuit 73 that A/D converts the data output from
0 and the A/D converted data are digitally operated to calculate the line voltage Vab, each phase current Ia, Ib, Ic, zero-sequence current I0, positive-sequence current I1, and negative-sequence current I2. , a calculation circuit 740 that calculates the ratio I2/I1 of the magnitude of the negative-sequence current I2 to the magnitude of the positive-sequence current I1, and the magnitude of the positive-sequence current I1 of the past few cycles based on the calculation data of the calculation circuit 740. By summing up the data of , and the data of the magnitude of the negative sequence current I2,
A memory 770 for storing average values <I1><I2> for each past m (m is assumed to be 5) cycles, calculation data from the calculation circuit 740, and the data stored in the memory 770. Number of positive sequence current I1 ~
Average value <I1> 10 cycles ago and current average value <I
A determination circuit that determines ground faults, short circuits, and disconnections based on the difference ΔI1 between the current average value <I2 > and the current average value <I2 > of the number of negative sequence currents I2 ~ 10 cycles ago. 750. The purpose of taking the average of the past m cycles is to prevent noise, and the difference between the average value <I1> several to ten cycles ago and the current average value <I1> is taken after the failure. This is because the circuit breaker does not work during the 10th cycle, so current flows.

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 of the current. 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. FIG. 7 is a flowchart showing the procedure for determining ground faults, short circuits, and disconnections performed by the determination circuit 750. According to FIG. 7, the determination circuit 750 includes the calculation circuit 74.
A short circuit determination (step (1)) is performed based on various current data supplied from 0, and if a short circuit is determined, a code representing a short circuit is sent to the transmitter 72.

If it is determined that there is no short circuit, a disconnection determination (step (2)) is performed, and if it is determined that the wire is disconnected, a code indicating the disconnection is sent out. If it is determined that there is no disconnection,
Perform ground fault determination (steps (3) and (4)). Ground fault determination is performed when the positive sequence current I1 is a constant value ΔI1 before and after the ground fault point.
This is based on the fact that the negative phase current I2 changes by ΔI2. In step (3),
The zero-sequence current I0 is compared with the threshold value Ix, and the zero-sequence current I0
If it exceeds the threshold value Ix, it is assumed that a ground fault has occurred, and in step (4), the change in the magnitude of the positive sequence current I1 ΔI1 and the magnitude of the change in the negative sequence current I2 ΔI2 are calculated.
It is determined whether the values exceed thresholds Iy and Iz, respectively. The threshold values Iy and Iz are determined in consideration of theoretical formulas and practical test results.

If YES in step (4), it is assumed that there is a ground fault on the load side from the terminal station, and a code representing "load side ground fault" is transmitted. If NO in step (4), it is assumed that there is a ground fault on the power supply side rather than the terminal station, and a code representing "power supply side ground fault" is transmitted. In this embodiment, the change in the magnitude of the positive sequence current I1 ΔI1
and the change ΔI2 in the magnitude of the negative phase current I2 is compared with the threshold value. The relationship between the phase angles of the positive-sequence current I1 and negative-sequence current I2 and the phase angles of their increments ΔI1 and ΔI2 differs depending on the conditions of the ground fault, so it cannot be said unconditionally, but unless there is a right-angled relationship by chance, This is because some change appears in the magnitude of the positive-sequence current I1 and the negative-sequence current I2.

[0029] Note that the ground fault determination in steps (3) and (4) means the determination of a one-wire ground fault, and in the case of a two-wire or three-wire ground fault, the short circuit determination in step (1) is used. Therefore, there is no need to determine whether there is a 2-wire ground fault or a 3-wire ground fault in steps (3) and (4). Also, when there is a short circuit or disconnection, a YES result appears in step (4), but step (
1) Priority is given to the determination of (2), so there is no chance of making a mistake in determining a disconnection or short circuit.

If it is determined that there is no ground fault, step (9)
A fault-free code 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 (1)).
0)). The master station 9 consists of a receiving section 91 and a failure section determining section 92, as shown in FIG. As shown in FIG. 8, the short circuit determination in step (1) is performed using each phase current I.
It is determined whether any of a, Ib, and Ic exceeds a reference current (for example, 1.2 times the rated current). In FIG. 8, the reference current is shown as 480A (rated current is 400A).

The disconnection determination in step (2) is performed for 1-wire disconnection, 2-wire disconnection, and 3-wire disconnection, as shown in FIG. In determining one wire disconnection, the line voltage Vab is set to a threshold value of 300.
exceeds 0V, any of the phase currents Ia, Ib, and Ic exceeds 1% of the rated current, and the positive-sequence current I1 and negative-sequence current I
The determination is made when the ratio I2/I1 of the size of 2 exceeds 0.6 times. In Figure 1, "1% of rated current" is 4
It is displayed as A. The number 0.6 times is determined empirically. In determining a two-wire disconnection, the line voltage V
ab is in the range of 40 to 100V, and each phase current Ia, I
A judgment is made when either b or Ic falls below 1% of the rated current. In determining 3-wire disconnection, the line voltage Va
The determination is made when b falls below 40V and any one of the phase currents Ia, Ib, and Ic falls below 0.1% of the rated current.

Failure section determination unit 92 of master station 9 (see FIG. 9)
determines in which section there is a ground fault, short circuit, or disconnection based on the code received from the transmitter 72 of each terminal through a medium such as radio, light, or infrared rays. The method for this determination is as follows. Assume that terminal stations 7a1, . . . , 7a6 are arranged along a power distribution line as shown in FIG.

When a one-wire ground fault occurs between the terminal station 7a3 and the terminal station 7a4 (see FIG. 10(a)), the power is sent from the terminal stations 7a1, 7a2, and 7a3 on the power transmission side from the ground fault point. The information that follows is information that represents a "load-side ground fault." However, terminal stations 7a4, 7a5, 7 on the load side from the ground fault point
The information sent from a6 is information indicating a "ground fault on the power supply side." Therefore, the master station 9 knows that a ground fault has occurred between the terminal station 7a3 and the terminal station 7a4, which have different information contents.

Next, when a short circuit failure occurs between the terminal station 7a3 and the terminal station 7a4 (see FIG. 10(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 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 located on the load side from the failure point is "broken wire" information (in the case of a two-wire short circuit) or "failure" information. "None" (in case of 3-wire short circuit). Therefore, 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. 10(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. For example, although the fundamental wave pulse generation circuit 760 generates pulses in synchronization with the power supply current, it may be synchronized completely independently of the power supply. In addition to the circuit shown in FIG. 1, it is also possible to use a circuit as shown in FIG. 11 as the circuit for determining whether one wire is disconnected. In the circuit of FIG. 11, determination is made when any of the phase currents Ia, Ib, and 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. In the circuit of FIG. 12, each phase current Ia
, Ib, Ic, one of which is less than 1% of the rated current and the other two are 1% or more of the rated current, and the line voltage Vab exceeds approximately 80% of the phase voltage, and the magnitude of the positive sequence current I1 and negative sequence current I2 The determination is made when the ratio I2/I1 exceeds 0.6 times. If the circuit shown in FIG. 12 is used, if a short-circuit fault occurs, all information sent from the terminal station on the load side of the fault point will be "no fault" information. Various other changes can be made without departing from the gist of the invention.

[0037]

Effects of the Invention As described above, according to the invention of the method for determining a disconnection section of a distribution line as set forth in claim 1, the correct The phase current I1 and the negative phase current I2 are determined, and the magnitude of the line voltage Vij between two predetermined phases of the distribution line obtained at the measurement point is compared with the threshold value Vth, and each phase current Ia, Ib is calculated.
, Ic and the positive sequence current I1 of the negative sequence current I2
By detecting the ratio to and comparing it with a threshold value, the disconnection fault point can be determined easily and reliably.

According to the invention of the distribution line disconnection section determining device according to claim 2, each phase current Ia, Ib is determined at each terminal station.
, Ic as well as the positive-sequence current I1 and the negative-sequence current I2 are detected and compared with a threshold value, and the magnitude of the line voltage Vij between two predetermined phases of the distribution line obtained at the measurement point is compared with the threshold value. However, if the disconnection data is transmitted to the master station, the master station can determine the disconnection section of the distribution line based on the data sent from each terminal station. In this case, there is no need to specifically measure voltage at the terminal station, so compared to the conventional method of measuring three-wire voltage, the configuration of the terminal station is simpler and costs can be reduced. This is especially advantageous when a large number of terminal stations are arranged.

According to the invention of the distribution line disconnection section determination device according to claim 3, each phase current Ia, Ib is determined at each terminal station.
, Ic as well as the positive-sequence current I1 and the negative-sequence current I2 and send them to the master station along with data on the magnitude of the line voltage Vij between two predetermined phases of the distribution line obtained at the measurement point. , the master station can determine the fact of the disconnection and the disconnected section of the distribution line based on the data sent from each terminal station. In this case, there is no need to specifically measure voltage at the terminal station, so compared to the conventional method of measuring three-wire voltage, the configuration of the terminal station is simpler and costs can be reduced. This is especially advantageous when a large number of terminal stations are arranged.

[Brief explanation of the drawing]

FIG. 1 is a logic circuit diagram for determining disconnection.

FIG. 2 is a diagram of a power distribution line showing a one-line disconnection state.

FIG. 3 is a diagram of a power distribution line showing a two-wire disconnection state.

FIG. 4 is an equivalent circuit diagram of a load showing a two-wire disconnection state.

FIG. 5 is a power distribution system diagram in which terminal stations are arranged.

FIG. 6 is a block diagram showing the internal configuration of an arithmetic processing unit provided in the terminal station.

FIG. 7 is a flowchart showing a procedure for determining ground faults, short circuits, and disconnections performed by the determination circuit.

FIG. 8 is a logic circuit diagram for determining a short circuit.

FIG. 9 is a block diagram showing the main part configuration of a master station.

FIG. 10 is a distribution line diagram for explaining a method for determining a fault section of a distribution line.

FIG. 11 is a logic circuit diagram showing another embodiment that performs one-line disconnection determination.

FIG. 12 is a logic circuit diagram illustrating yet another embodiment that performs one-line disconnection determination.

[Explanation of symbols] 4a, 4b Distribution lines 7a1, 7a2, 7b1, 7b2 Terminal station 72 Transmitter 740 Calculation circuit 9 Master station 92 Failure area determination unit CT1, CT2, CT3 Current sensor T1, T2
terminal station

Claims (3)

[Claims] Claim 1: A method for determining a disconnection section of a distribution line when a disconnection fault occurs in the distribution line, the distribution line being divided into a plurality of sections, and each phase current I of the distribution line being measured at a measurement point in each section.
a, Ib, and Ic, and calculate the positive-sequence current I1 and negative-sequence current I2 based on these detected currents, and set the magnitude of each phase current Ia, Ib, and Ic based on the rated current of the distribution line. The threshold value Iax, I corresponding to each phase
by and Icz, and compare the ratio I2/I1 of the magnitude of the positive sequence current I1 and the magnitude of the negative sequence current I2 with a threshold value k0 set to 0.5 or more and less than 1, and The disconnection section is determined by comparing the magnitude of the line voltage Vij between two predetermined phases of the distribution line obtained at the point with a threshold value Vth set based on the rated line voltage. Method for determining disconnection sections of distribution lines. [Claim 2] A terminal station is arranged in each section of a distribution line divided into a plurality of sections, and each terminal station is provided with a current Ia of each phase of the distribution line,
A current sensor that detects Ib, Ic and a threshold value set based on the rated line voltage of the line voltage Vij between two predetermined phases of the distribution line, which is the control AC power supply voltage of the terminal station. A voltage comparison means for comparing with Vth and a positive sequence current I1 and a negative sequence current I2 based on the detected current of the current sensor.
calculation means for calculating each phase current Ia, Ib, Ic
The magnitude of the threshold values Iax, Iby, and Ic corresponding to each phase are set based on the rated current of the distribution line, respectively.
a first current comparison means for comparing with z and a ratio I2/I1 of the magnitude of the positive sequence current I1 and the magnitude of the negative sequence current I2;
a second current comparison means that compares the current with a threshold value k0 set to 0.5 or more and less than 1; a wire breakage determination means that determines a wire breakage point; and a transmission means that transmits data of the determination result of the wire breakage determination means. Further, a master station is arranged to receive data from the terminal station, and the master station has different determination results based on the determination results included in the data received from each terminal station. The power distribution line is characterized by being provided with a disconnection section determination means for distinguishing terminal station groups and determining a section existing between mutually adjacent terminal stations among the differentiated terminal station groups as a disconnection section of the distribution line. Distribution line disconnection section determining device. 3. A disconnection section determining device for a distribution line that determines a disconnection section when a disconnection fault occurs in a distribution line, wherein a terminal station is arranged in each section of a distribution line divided into a plurality of sections, and each The terminal station includes a current sensor that detects each phase current Ia, Ib, and Ic of the distribution line, a calculation means that calculates the positive-sequence current I1 and the negative-sequence current I2 based on the detected current of the current sensor, and the calculation means. A transmitting means for transmitting data of the calculation result and data of the line voltage Vij between two predetermined phases of the distribution line obtained at the measurement point, and further comprising a master station for receiving data from the terminal station. Based on the data received from each terminal station, this master station determines the magnitude of the line voltage Vij between two predetermined phases of the distribution line, which is the AC power supply voltage for control of the terminal station, on the rated line. voltage comparison means for comparing with a threshold value Vth set based on the voltage across the line; Threshold I
ax, Iby, and Icz, and a threshold value that sets the ratio I2/I1 of the magnitude of the positive sequence current I1 and the magnitude of the negative sequence current I2 to 0.5 or more and less than 1. a second comparing means that compares k0 with a second comparing means to determine a disconnection point; 1. A disconnection section determining device for a power distribution line, comprising: a disconnection zone determining means for determining a section where the disconnection occurs as a disconnection section of the distribution line.