WO2019092850A1

WO2019092850A1 - Ground fault point locating system and ground fault point locating method

Info

Publication number: WO2019092850A1
Application number: PCT/JP2017/040607
Authority: WO
Inventors: 大原　久征; 松本　隆治
Original assignee: 中国電力株式会社
Priority date: 2017-11-10
Filing date: 2017-11-10
Publication date: 2019-05-16
Also published as: JP6327411B1; JPWO2019092850A1

Abstract

This ground fault point locating system comprises: a first sensor that detects first currents and first voltages for each phase of a power line at a first position on the power line, a second sensor that detects second currents and second voltages for each phase of the power line at a second position on the power line, a first calculation device for calculating a first zero-phase current and first zero-phase voltage at the time of a fault on the basis of the detection results of the first sensor, a second calculation device for calculating a second zero-phase current and second zero-phase voltage at the time of the fault on the basis of the detection results of the second sensor, a third calculation device for calculating the surge arrival time difference between the first position and second position on the basis of first information associating the first zero-phase current and first zero-phase voltage with the current time and second information associating the second zero-phase current and second zero-phase voltage with the current time, a storage device in which information indicating a first surge propagation speed from the first position to the second position and a second surge propagation speed from the first position to the second position that is faster than the first surge propagation speed are stored beforehand, and a ground fault point locating device for locating the ground fault on the basis of information indicating the distance between the first position and the second position, the surge arrival time difference, the first surge propagation speed, and the second surge propagation speed.

Description

Earth fault localization system, earth fault localization method

The present invention relates to a ground fault localization system and a ground fault localization method.

For example, Patent Document 1 below is known as a system for locating a ground fault point when a ground fault occurs in a power line.

The system disclosed in Patent Document 1 is obtained from a plurality of slave stations including a plurality of slave stations having voltage current sensors disposed at predetermined intervals with respect to a power line and detecting zero-phase voltage and zero-phase current. And a master station that receives information indicating an accident direction and a surge waveform relating to a ground fault. Then, when a ground fault occurs on the power line, the master station first identifies an accident section based on information obtained from a plurality of slave stations, and then, a pair of slave stations in an arrangement relationship sandwiching the accident section Next, ground fault localization in multiple pairs of slave stations is performed based on data of surge arrival time and power line length detected from data of surge waveforms obtained from multiple pairs of slave stations. The surge propagation speed at which the variation in position is minimized is calculated, and then the ground fault points in the plurality of slave stations are calculated based on the data of the surge propagation speed, the surge arrival time, and the power line length, and then A value obtained by averaging the ground fault points is output as a ground fault point localization position.

Patent No. 4039576

However, in the case of Patent Document 1 described above, since it is necessary to select a plurality of pairs of substations sandwiching a ground fault point, there is a possibility that the equipment cost for installing a plurality of substations may become high.

Then, an object of this invention is to provide the ground fault point localization system and the ground fault point localization method which held down the installation cost.

The main present invention for solving the problems described above is, as a ground fault localization system, comprising: a first sensor for detecting a first current and a first voltage of each phase of the power line at a first position of the power line; The first zero phase current and the first zero phase at the time of occurrence of the accident based on the detection result of the second sensor that detects the second current and the second voltage of each phase of the power line at two positions. A second calculation device for calculating a second zero-phase current and a second zero-phase voltage at the time of occurrence of an accident based on a first calculation device for calculating a voltage, and a detection result of the second sensor; The first information in which the current and the first zero-phase voltage are associated with the current time, and the second information in which the second zero-phase current and the second zero-phase voltage and the current time are associated with each other At the time of surge arrival between the first position and the second position based on A third calculation device for calculating a difference, and a surge propagation velocity between the first position and the second position, the second surge propagation velocity being faster than the first surge propagation velocity and the first surge propagation velocity And a distance between the first position and the second position, the surge arrival time difference, the first surge propagation speed, and the second surge propagation speed. And a ground fault localization device that locates a ground fault based on the information.

Other features of the present invention will become apparent from the accompanying drawings and the description of the present specification.

According to the present invention, it is possible to provide a ground fault localization system and a ground fault localization method capable of reducing equipment cost and securing a certain level of positioning accuracy.

It is a figure showing a ground fault point locating system concerning this embodiment. It is a figure showing the 1st and 2nd sensor concerning this embodiment. It is a figure which shows the characteristic of the core of the 1st and 2nd sensor concerning this embodiment. It is a figure which shows a part of characteristic of the winding core of the 1st and 2nd sensor concerning this embodiment. It is a figure which shows the example of installation of the ground fault point localization system which concerns on this embodiment. It is a figure which shows the other example of installation of the ground fault point localization system which concerns on this embodiment. It is a figure for demonstrating the ground fault point localization method which concerns on this embodiment.

At least the following matters will be made clear by the present specification and the description of the accompanying drawings.

=== Ground fault localization system ===
FIG. 1 is a diagram showing a ground fault localization system according to the present embodiment. In the present embodiment, the ground fault point determination system will be described below as a system for locating a ground fault point when, for example, a ground fault occurs on a distribution line. In addition, although the distribution line has three phases, for convenience of explanation, only one line will be shown.

The ground fault localization system 1 is a system for locating a point (ground fault point P) at which a ground fault occurs when a ground fault occurs in a power system (for example, a 6 kV distribution system in the present embodiment).

The ground fault localization system 1 includes a first sensor 100, a second sensor 200,

measurement terminals

300 and 400, and a ground fault localization device 500 as means for locating the ground fault P. .

The first sensor 100 is a sensor that detects the voltage and current at the first position of the distribution line 10. As shown in FIG. 2, the first sensor 100 includes a core 100 A disposed to surround the distribution line 10 and a coil 100 B wound around the core 100 A. The second sensor 200 is a sensor that detects the voltage and current at the second position of the distribution line 10. As shown in FIG. 2, the second sensor 200 also includes a core 200 A disposed to surround the distribution line 10 and a coil 200 B wound around the core 200 A. Details of the first sensor 100 and the second sensor 200 will be described later.

Here, the first position is, for example, a position where the first sensor 100 surrounds the distribution line 10 supported by the utility pole 20 erected at the predetermined position. Further, the second position is a position where the second sensor 200 surrounds the distribution line 10 supported by the utility pole 30 erected at a position separated by a predetermined distance from the utility pole 20. In addition, since the measurement terminal 300 is installed near the first sensor 100 and the measurement terminal 400 is installed near the second sensor 200, the installation position of the measurement terminal 300 is the first position. The installation position can be regarded as the second position.

The first sensor 100 is housed in a storage box 40 of a high-speed automatic switch mounted on a metal arm on the utility pole 20. The second sensor 200 is housed in a storage box 50 of a high-speed automatic switch mounted on a metal arm on the utility pole 30.

Measurement terminal 300 calculates the zero-phase current and zero-phase voltage from the values of the current and voltage detected by first sensor 100, and associates the information with the current time information acquired from GPS satellite 600, via communication line 700. It transmits to ground fault point localization apparatus 500. Similarly, the measurement terminal 400 calculates the zero-phase current or zero-phase voltage from the values of the current or voltage detected by the second sensor 200, associates the zero-phase current or zero-phase voltage with the information of the current time acquired from the GPS satellite 600, It transmits to the ground fault localization apparatus 500 via 700.

The ground fault localization apparatus 500 calculates the surge arrival time to the first position from the information acquired from the measurement terminal 300, and further calculates the surge arrival time to the second position from the information acquired from the measurement terminal 400. Then, the surge arrival time difference between the first position and the second position is calculated. In addition, the ground fault localization apparatus 500 has a storage device 800 that stores the actual value of the surge propagation speed calculated in the past. The surge propagation speed can be determined, for example, by a known method as disclosed in Japanese Patent No. 4039576. The storage device 800 stores information on the plurality of surge propagation speeds obtained in this manner as actual values. Then, the ground fault localization apparatus 500 measures the surge arrival time difference between the first position and the second position, the distance between the first position and the second position, and the surge propagation stored in the storage device 800. The ground fault point P is located based on the information indicating the maximum and minimum surge propagation speeds among the speeds.

=== 1st and 2nd sensors ===
In the case of the first sensor 100, when a ground fault current flows in the distribution line 10, the magnetic flux of the core 100A changes, and the current flowing through the coil 100B changes accordingly. The ground fault current flowing through the distribution line 10 can be detected by detecting the current flowing through the coil 100B with a detector (not shown).

Here, the core 100A is formed such that the magnetic flux density B of the magnetic flux generated when the ground fault current flows in the distribution line 10 is equal to or less than a predetermined value.

By forming the first sensor 100 so that the magnetic flux density B of the magnetic flux generated in the winding core 100A becomes as small as possible, the range of the ground fault current detectable by the first sensor 100 can be expanded. For example, even if the grounding method of the transformer of the 6 kV distribution system is either the resistive grounding method or the non-grounding method, it is possible to reliably detect the ground fault current.

By reducing the magnetic flux density B generated in the winding core 100A to be equal to or less than a predetermined value, it is possible to reduce the variation in the measured value of the first sensor 100 mounted on each phase of the distribution line 10 Can be measured in a wide band.

FIG. 3 is a graph showing the relationship between the relative magnetic permeability μr of the core 100A and the magnetic flux density B of the magnetic flux generated in the core 100A. Although FIG. 3 exemplifies a characteristic curve in the case where the winding core 100A is a permalloy core, it is understood that the value of the relative magnetic permeability μr largely differs depending on the magnetic flux density B.

For this reason, in order to suppress the variation in the characteristics of the first sensor 100A in each phase in the distribution line 10, the magnetic flux density B in a range in which the fluctuation of the relative permeability μr becomes as small as possible is generated in the winding core 100A. You need to

Referring to FIG. 3, it can be seen that the smaller the magnetic flux density B, the smaller the fluctuation of the relative magnetic permeability μr. Therefore, the relationship between the magnetic flux density B and the relative magnetic permeability μr when the magnetic flux density B is 3000 gausses or less is shown enlarged in FIG.

The relationship between the change in relative permeability μr and the change in magnetic flux density B is linear, that is, the rate of increase in magnetic flux density B and the rate of increase in relative permeability μr when the ground fault current flows through the distribution line 10 coincide. If related, the change of the relative magnetic permeability μr is stabilized against the change of the magnetic flux density B. Then, the range of the magnetic flux density B in which the relative magnetic permeability μr is stabilized is an area where the variation in measurement by the first sensor 100 installed in each phase of the distribution line 10 is small.

Referring to FIG. 4, the range in which the relative magnetic permeability μr linearly increases with the increase in the magnetic flux density B is a range in which the magnetic flux density B is 1000 gausses or less. That is, it is understood that forming the winding core 100A in the range where the magnetic flux density B is 1000 gausses or less is desirable in terms of suppressing the variation of the measurement by the first sensor 100 and performing accurate measurement. In the present embodiment, the first sensor 100 is formed such that the magnetic flux density B is an appropriate value within the range of 1000 gauss or less.

Further, the magnetic flux density B of the magnetic flux generated in the core 100A is proportional to the magnetic flux but inversely proportional to the cross-sectional area S and the length (circumferential length) L of the core 100A. Therefore, the core 100A is formed to have a cross-sectional area S and a length L such that the magnetic flux density B of the magnetic flux generated in the core 100A is suppressed to 1000 gausses or less when the ground current is generated. Just do it.

Further, when the distribution line 10 is grounded, the current flowing through the coil 100B is inversely proportional to the number of turns of the coil 100B. Therefore, the number of turns of the coil 100B according to the present embodiment is set such that the magnetic flux density B is, for example, 1000 gauss or less. As a result, even a weak ground fault current can be detected by increasing the level of the secondary current, so that the detectable range of the ground fault current can be expanded.

The second sensor 200 is also configured in the same manner as the first sensor 100, so the description of the second sensor 200 is omitted.

=== Example of installation of ground fault localization system === =
FIG. 5 is a view showing an installation example of the ground fault localization system according to the present embodiment. Moreover, FIG. 6 is a figure which shows the example of another installation of the ground fault point localization system which concerns on this embodiment.

In FIG. 5, a storage box 40 (50) for a high-speed automatic switch is installed in an arm metal mounted in a horizontal direction with respect to the electric pole 20 (30). In the storage box 40 (50) The first sensor 100 (second sensor 200) is installed. Moreover, the measurement terminal 300 (400) is installed in the other arm metal attached to the horizontal direction with respect to the telephone pole 20 (30). Further, the remote control station 900 (1000) is attached to the other arm metal attached in the horizontal direction with respect to the electric pole 20 (30). Although the first sensor 100 (second sensor 200) and the measurement terminal 300 (400) are connected by the communication line 1100 (1200) for signal transmission, the measurement terminal 300 (400) and the ground fault localization device 500 are , And is connected by a communication line 1300 (1400) for the remote control station 900 (1000).

In addition, it is not limited to the aspect of FIG. 5, As shown in FIG. 6, you may connect between measurement terminal 300 (400) and the ground fault point localization apparatus 500 by wireless communication.

=== How to locate the ground point ====
FIG. 7 is a view for explaining the positioning method of the ground fault localization system according to the present embodiment.

The position (first position) of the measurement terminal 300 is G1, the position (second position) of the measurement terminal 400 is G2, and the distance between the measurement terminal 300 and the measurement terminal 400 is 2941 m, for example.

First, it is assumed that a ground fault has occurred at a position somewhere between the measurement terminal 300 and the measurement terminal 400. At this time, the ground fault localization apparatus 500 calculates the surge arrival time TA to the measuring terminal 300 based on the information obtained from the measuring terminal 300, and the surge to the measuring terminal 400 based on the information obtained from the measuring terminal 400. The arrival time TB is calculated, and the surge arrival time difference TB-TA between the

measurement terminals

300 and 400 is calculated from the surge arrival times TA and TB. For example, assuming that the surge arrival time TA = 6.09999545 seconds and the surge arrival time TB = 6.10,000945 seconds, the surge arrival time difference TB-TA = 14 μsec.

Next, the ground fault localization apparatus 500 indicates the surge propagation velocity VMIN indicating the minimum value and the maximum value from among a plurality of data representing the surge propagation velocity as the actual value stored in advance in the storage device 800. Read out two values of the surge propagation velocity VMAX.

In order to determine the ground fault point P, the following calculation formula (1) is used.

P = (M / 2)-(Δt · v / 2) (1)
However, M: distance between

measurement terminals

300 and 400 Δt: surge arrival time difference v: surge propagation speed Therefore, the ground fault localization apparatus 500 uses the calculation formula (1) to determine the ground when the surge propagation speed is VMIN. An operation is performed to locate the junction point P1 and the ground junction point P2 when the surge propagation velocity is VMAX. For example, it is assumed that the surge propagation velocity VMAX = 200 m / μsec and the surge propagation velocity VMIN = 120 m / μsec. These surge propagation speeds VMAX and VMIN are highly reliable values because they are past actual values. An actual ground fault point P is an example where it is a point of 504 m from the measuring terminal 300, for example.

First, when the surge propagation velocity VMIN is used, the ground fault point P1 to be measured is 630 m from the measuring terminal 300, and the positioning error is 126 m.

On the other hand, when the surge propagation speed NMAX is used, the ground fault point P2 to be measured is 70 m from the measuring terminal 300, and the positioning error is 434 m.

As described above, when the ground fault point P is determined using the past actual value as the surge propagation speed, the positioning error of the ground fault point is about several hundred meters even if the maximum value of the surge propagation speed is used. It becomes possible to hold down. This makes it possible to detect the cause of the blackout due to the ground fault at an early stage and solve it at an early stage.

=== Summary ===
As described above, the ground fault localization system 1 according to the present embodiment includes the first sensor 100 that detects the current and voltage of each phase of the distribution line 10 at the first position G1 of the distribution line 10, and the distribution line At the second position G2 of 10, based on the detection result of the second sensor 200 for detecting the current and voltage of each phase of the distribution line 10 and the first sensor 100, the first zero-phase current and Based on the detection result of the measurement terminal 300 (first calculation device) that calculates the zero phase voltage and the detection result of the second sensor 200, the measurement terminal 400 that calculates the second zero phase current and the second zero phase voltage when an accident occurs Second calculation device), first information in which the first zero-phase current and the first zero-phase voltage are associated with the current time, and the second zero-phase current and the second zero-phase voltage and the current time are associated The first position G1 and the second position G2 based on the second information Ground propagation point localization apparatus 500 (third calculation apparatus) for calculating the surge arrival time difference TB-TA between these, and the surge propagation speed between the first position G1 and the second position G2, which is the first surge propagation Storage device 800 in which information indicating the velocity VMIN and the second surge propagation velocity VMAX faster than the first surge propagation velocity VMIN is stored in advance, the distance L between the first position G1 and the second position G2, surge arrival A ground fault localization apparatus 500 for positioning the ground fault P based on information indicating each of the time difference TB-TA and the surge propagation speeds VMIN and VMAX.

And by adopting the ground fault point localization system 1 according to the present embodiment, it becomes possible to provide a system with a reduced installation cost as a permanent installation type system. In addition, since the value obtained as the actual value as the surge propagation speed is read out from the storage device to locate the ground fault point, it becomes possible to locate the ground fault point by a simple calculation.

Further, in the present embodiment, the first surge propagation velocity is the minimum value VMIN among the plurality of actual values calculated in the past, and the second surge propagation velocity is the largest among the plurality of actual values calculated in the past. It is a value VMAX.

And, even if VMAX is used as the surge propagation speed, since the positioning error can be suppressed to several hundred meters, it becomes possible to provide a positioning system with low facility cost and high positioning accuracy.

In the present embodiment, the first sensor 100 is housed in the storage box 40 of the high-speed automatic switch installed at the first position G1, and the second sensor 200 is installed at the second position G2. It is stored in a storage box 50 on the wall.

As described above, since the first sensor 100 and the second sensor 200 are protected by the

storage boxes

40 and 50, respectively, they can be protected from deterioration caused by external factors, and the ground fault point can be maintained for a long time. It will be possible to continue accurate positioning of

Further, in the present embodiment, the first sensor 100 detects an annular core 100A disposed so as to surround the distribution line 10 at the first position G1, and a ground fault current generated when the distribution line 10 has a ground fault. And the second sensor 200 includes an annular winding core 200A disposed to surround the distribution line 10 at the second position G2, and the distribution line 10 And a coil 200B wound around a core 200A to detect a ground fault current generated when a ground fault occurs, wherein the

core

100A, 200A is a magnetic flux generated when the ground fault current flows in the distribution line 10 The magnetic flux density B is formed to be, for example, 1000 gausses or less based on the ratio of the magnetic permeability μr to the magnetic flux density B. In particular, the magnetic flux density B of 1000 gausses or less is a value such that the ratio of the change of the magnetic permeability to the change of the magnetic flux density B is constant. Therefore, the variation in the measurement values of the first sensor 100 and the second sensor 200 can be reduced, and the ground fault current can be accurately measured in a wide band. That is, the accuracy of the ground fault point P calculated and positioned using the surge propagation velocity which is the actual value with respect to the information of the two points of the first position G1 and the second position G2 becomes high.

Further, in the present embodiment, the cross-sectional area S and the length L of the winding

cores

100A and 200A may be set as values inversely proportional to the magnetic flux density B in order to increase the accuracy of the determination of the ground fault point P. .

The above embodiments are for the purpose of facilitating the understanding of the present invention, and are not for the purpose of limiting the present invention. The present invention can be modified and improved without departing from the gist thereof, and the present invention also includes the equivalents thereof.

DESCRIPTION OF SYMBOLS 1 Ground fault point determination system 10

Distribution line

20, 30

Power pole

40, 50 Storage box 100 1st sensor 100A Core 100B Coil 200 2nd sensor 200A Core 200B Coil 300, 400 Measurement terminal 500 Ground point localization device 600 GPS satellite 700 communication line 800

storage unit

900, 1000

distance control station

1100, 1200, 1300, 1400 communication line

Claims

A first sensor for detecting a first current and a first voltage of each phase of the power line at a first position of the power line;
A second sensor that detects a second current and a second voltage of each phase of the power line at a second position of the power line;
A first calculation device that calculates a first zero-phase current and a first zero-phase voltage at the time of occurrence of an accident based on the detection result of the first sensor;
A second calculation device for calculating a second zero-phase current and a second zero-phase voltage at the time of occurrence of an accident based on the detection result of the second sensor;
The first information in which the first zero-phase current and the first zero-phase voltage are associated with the current time, and the second zero-phase current and the second zero-phase voltage are associated with the current time A third calculation device that calculates a surge arrival time difference between the first position and the second position based on two pieces of information;
A memory in which information indicating a surge propagation velocity between the first position and the second position, the first surge propagation velocity and a second surge propagation velocity faster than the first surge propagation velocity is stored in advance A device,
A ground fault that locates a ground fault point based on information indicating the distance between the first position and the second position, the surge arrival time difference, the first surge propagation velocity, and the second surge propagation velocity. Point positioning device,
The ground fault rating system characterized by having.
The first surge propagation velocity is a minimum value among a plurality of actual values calculated in the past,
The ground fault assessment system according to claim 1, wherein the second surge propagation velocity is a maximum value among a plurality of actual values calculated in the past.
The first sensor is built in a first switch installed at the first position,
The ground fault assessment system according to claim 1 or 2, wherein the second sensor is built in a second switch installed at the second position.
The first sensor includes an annular first core disposed to surround the power line at the first position, and the first core to detect a ground fault current generated when the power line is grounded. And a first coil wound on the
The second sensor includes an annular second core disposed to surround the power line at the second position, and the second core for detecting a ground fault current generated when the power line is grounded. And a second coil wound on the
The first core and the second core are formed such that the magnetic flux density of the magnetic flux generated when the ground current flows through the power line is equal to or less than a predetermined value based on the ratio of the magnetic permeability to the magnetic flux density The ground fault rating system according to any one of claims 1 to 3, characterized in that:
The ground fault evaluation system according to claim 4, wherein the predetermined value is a value within a range in which the ratio of the magnetic permeability to the magnetic flux density is constant.
The ground fault evaluation system according to claim 4 or 5, wherein each of the first and second cores has a cross-sectional area and a length such that the magnetic flux density is equal to or less than the predetermined value.
The ground fault evaluation system according to any one of claims 1 to 6, wherein the power line is a distribution line installed in a 6 kV distribution system.
A first sensor detects a first current and a first voltage of each phase of the power line at a first position of the power line,
A second sensor detects a second current and a second voltage of each phase of the power line at a second position of the power line,
A first calculation device calculates a first zero-phase current and a first zero-phase voltage at the time of occurrence of an accident based on the detection result of the first sensor,
The second calculation device calculates a second zero phase current and a second zero phase voltage at the time of occurrence of an accident based on the detection result of the second sensor,
The third calculation device is configured to: first information in which the first zero phase current and the first zero phase voltage are associated with the current time; the second zero phase current and the second zero phase voltage; and the current time Calculating a surge arrival time difference between the first position and the second position, based on the second information associated with
The storage device is a surge propagation velocity between the first position and the second position, and information indicating the first surge propagation velocity and the second surge propagation velocity faster than the first surge propagation velocity is provided in advance. Remember
A ground fault assessment device is configured to determine the ground based on information indicating the distance between the first position and the second position, the surge arrival time difference, the first surge propagation velocity, and the second surge propagation velocity, respectively. A ground point assessment method characterized by specifying a junction point.
The first surge propagation velocity is a minimum value among a plurality of actual values calculated in the past,
The ground fault evaluation method according to claim 8, wherein the second surge propagation speed is the maximum value among a plurality of actual values calculated in the past.
The said power line is a distribution line installed in a 6 kV distribution system. The ground fault evaluation method according to claim 8 or 9 characterized by things.