KR20230081232A - Power line fault localization method and apparatus - Google Patents

Abstract

The method for determining the fault point of a line according to the present invention comprises the steps of constructing a line constant DB consisting of line constant information for each section of a target line; obtaining measured values of voltage and current of a line at the time of failure; Calculating a normal component impedance by applying the measured value of the line at the time of failure and each line constant value on the line constant DB; For each section of the line, checking a difference between the calculated positive impedance and the positive impedance described in the line constant DB; and estimating a reference point of a section having the smallest difference as a failure point.

Description

Line failure point expression method and device {POWER LINE FAULT LOCALIZATION METHOD AND APPARATUS}

The present invention relates to a method and apparatus for finding a fault point on a line, and more particularly, a method for finding a fault point on a line that accurately calculates a fault point when a ground fault occurs in a complex line (eg: overhead + underground) or an underground line (eg: one-end grounding point) and devices.

The power system is becoming more and more important socially. Maintenance and operation of power systems requires a lot of effort. For example, when an accident occurs in a power transmission line, the location of the accident must be identified and the state of equipment at the location of the accident must be quickly confirmed. For this reason, a failure point locating device that calculates the distance from the substation to the location of the accident based on the power measurement information at the time of the accident is applied, contributing to reducing the effort for operation maintenance.

However, since the conventional failure point finding device is composed of hardware equivalent to a digital protection control device, there is a problem in that equipment cost is high.

In addition, since the indicator displaying the fault point identification result can only display limited information, for example, it can only display the distance from the substation to the accident point, the accident occurrence, etc., and it is difficult to accurately specify the location of the fault point. It was difficult.

In the case of line failure point expression using a distance protection relay widely used in Korea, in case of a short circuit failure, even in the case of a single line type processing and underground line, the fault point expression of the protection relay is relatively accurate, and the complex line (overhead + underground) or Even in the case of lines of different types, even if the protection relay's fault point expression is somewhat inaccurate, it is possible to correct the fault point through the fault point expression program.

On the other hand, when a ground fault occurs in a complex line (overhead + underground) or a heterogeneous line, in particular, due to the complexity of an underground line with one-end grounding point, the expression of the fault point of the protection relay is very inaccurate.

Improvement of Transmission Cable Line Constant Calculation Criteria Based on Post-Failure Analysis (Journal of Electrical Society 69(11), 2020.11, 1649-1658) Development and application of EMTP pre- and post-processor for symmetrical impedance analysis of underground transmission lines (Journal of the Korean Electrical Society 63(10), 2014.10, 1364-1370)

An object of the present invention is to provide a line fault point detection method and apparatus capable of accurately determining the fault point even when a ground fault occurs in a complex line or a heterogeneous line.

A method for determining a line fault point according to an embodiment of the present invention includes configuring a line constant DB composed of line constant information for each section of a target line; obtaining measured values of voltage and current of a line at the time of failure; Calculating a normal component impedance by applying the measured value of the line at the time of failure and each line constant value on the line constant DB; For each section of the line, checking a difference between the calculated positive impedance and the positive impedance described in the line constant DB; and estimating a reference point of a section having the smallest difference as a failure point.

Here, the step of constructing the line constant DB may include deriving a line constant from a connection point to each reference installation from construction information on reference installations of the target line; and virtually dividing a line between two consecutive reference installations into reference division points, and linearly calculating a line constant from the connection point to each reference division point.

Here, the reference installation is a junction box of a three-phase underground transmission line, and the construction information may include grounding treatment information for each junction box.

Here, in the step of calculating the normal component impedance, the normal component impedance may be calculated according to the following equation.

Here, in the step of securing the voltage and current measurement values of the line at the time of failure, the voltage and current measurement values at the time of failure may be received from the protective relay at the connection point, or the failure record data may be received from the line management server. .

Here, in the line constant DB, for a plurality of reference points on the line, positive-segment impedance and zero-segment impedance from a connection point to each reference point may be described.

An apparatus for determining a line fault point according to another embodiment of the present invention includes a line constant DB composed of line constant information for each section of a target line; a failure data acquisition unit that obtains measured values of voltage and current of a line when a failure occurs; and by applying the measured value of the line at the time of the failure and each line constant value on the line constant DB to calculate the constant impedance, and for each section of the line, the calculated constant impedance and the line constant DB A failure point estimating unit may be included that checks the difference in the described positive impedance and estimates the reference point of the section with the smallest difference as the failure point.

Here, the line constant DB may include: an installation line constant DB in which line constants from a connection point derived from construction information on reference installations of the target line to each reference installation are recorded; and a dividing line constant acquisition unit that virtually divides a line between two consecutive reference installations into reference dividing points and obtains a dividing line constant calculated linearly from the connection point to each reference dividing point. can

Here, the reference installation is a junction box of a three-phase underground transmission line, and the construction information may include grounding treatment information for each junction box.

Here, the fault point estimator may include a normal-segment impedance calculation unit that calculates the normal-sense impedance according to the following equation.

Here, the failure data acquisition unit may receive failure record data including measured values of voltage and current before performing a protection operation of the relay after recognizing the failure from the line management server.

Here, a result output unit may further include outputting the expressed failure point information in the form of a display screen or a report.

Here, the result output unit may output the possibility of a description error in the construction information of the target line.

If the line fault point finding method and/or device according to the spirit of the present invention having the above configuration is implemented, there is an advantage in that the fault point can be accurately determined even when a ground fault occurs in a complex line or a heterogeneous line.

The method and/or device for determining the fault point of the line according to the present invention has an advantage in that it can be applied to accurately determine the fault point regardless of one-end grounding point, underground line with an insulated junction box, composite line (overhead + underground), or heterogeneous line type.

The line fault finding method and/or device of the present invention has the advantage of being able to check errors in cable grounding construction information or line data by reversely using the error between the fault point expression and the actual fault point.

1A is a flowchart illustrating an embodiment of a line failure point determination method according to the spirit of the present invention.
FIG. 1B is a detailed flowchart illustrating the method of identifying a line fault point of FIG. 1A by embodying equations applied as a transmission line fault point identification algorithm.
2 is a circuit diagram illustrating an aspect in which impedance appears at a connection point during a ground fault according to the spirit of the present invention.
3 is a conceptual diagram showing division of sections in performing a fault point determination according to the spirit of the present invention with respect to an underground transmission line;
4 is a block diagram showing an embodiment of a line failure point detection device according to the spirit of the present invention.
FIG. 5 is a graph showing positive-segment impedance and zero-segment impedance at each installation point in FIG. 3;
6 is a simulation circuit diagram of an underground transmission line having a section configuration shown in FIG. 3;
FIG. 7 is a conceptual diagram illustrating division of sections in performing a fault point determination according to the idea of the present invention with respect to a complex transmission line in the form of an underground + overhead line.
FIG. 8 is a graph showing positive-segment impedance and zero-segment impedance at each installation (connection box and steel tower) point in FIG. 7;
9 is a simulation circuit diagram of a complex transmission line having a section configuration shown in FIG. 7;

In describing the present invention, terms such as first and second may be used to describe various components, but the components may not be limited by the terms. Terms are only for the purpose of distinguishing one element from another. For example, a first element may be termed a second element, and similarly, a second element may be termed a first element, without departing from the scope of the present invention.

When a component is referred to as being connected or connected to another component, it may be directly connected or connected to the other component, but it may be understood that another component may exist in the middle. .

Terms used in this specification are only used to describe specific embodiments, and are not intended to limit the present invention. Singular expressions may include plural expressions unless the context clearly dictates otherwise.

In this specification, the terms include or include are intended to designate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, and one or more other features or numbers, It can be understood that the presence or addition of steps, operations, components, parts, or combinations thereof is not precluded.

In addition, shapes and sizes of elements in the drawings may be exaggerated for clearer description.

The fault point expression according to the spirit of the present invention is particularly useful in the event of a ground fault. This is because there are conventional technologies that can be usefully applied in the case of a short circuit fault, but there is no simple and accurate expression method in the case of a ground fault.

For ground faults, since the ratio of Z ₀ (zero-sequence impedance) and Z ₁ (normal-segment impedance) affects the fault point expression, this must be considered. The fault point correction method used in the fault point identification program applies only the ratio of Z ₁ (normal impedance) for complex lines (overhead + underground) and heterogeneous lines.

In particular, in the case of an underground cable including an insulated junction box and a one-end grounding point where the K value (Z ₀ /Z ₁ ) as a line constant changes non-linearly, it is difficult to expect the accuracy of the fault point expression with the existing method.

In view of the characteristics of ground faults, the present invention theoretically calculates the fault point using the K value (Z ₀ /Z ₁ ) at the fault point at the time of failure, and the fault point is the same as Z ₁ of the previously obtained K value. Using , it is proposed to reflect the failure point expression algorithm.

That is, a method of calculating the fault point using the subdivided K value (Z ₀ /Z ₁ ) of the transmission line, comparing it with Z ₁ of the K value used in the calculation, and outputting the final fault point when the error is the smallest. present.

In general, while grounding is important for three-phase transmission lines to maintain mutual equilibrium, it is difficult to uniformly apply the grounding method due to the environmental conditions of the installation area of the transmission line. Retain/manage information. The subdivided K value of the transmission line used in the present invention can be easily calculated from the construction information of the transmission line held/managed in a separate facility management server.

As a method of calculating the K value (Z ₀ /Z ₁ ) from the grounding construction information of the transmission line, one or more of the techniques found in a number of known documents, such as papers cited as non-patent prior art documents, can be applied. can

In the present invention, the section between connection points where system power is supplied and main protection relays are installed is called a line, and a junction box or a steel tower installed in the middle of one line path is called a reference installation, and each reference at the connection point of the line The length area on the track to the installation is called a section. For more precise expression of the fault point, the partial line between two adjacent reference installations on the line is virtually divided again into a predetermined number, and the points on the partial line for virtual division are called reference dividing points, and the connection point of the corresponding line A length region on the track from to each reference dividing point is called a section. In addition, the reference installation and the reference division point may be collectively referred to as a reference point, and in this case, a length area on the track from a connection point of the corresponding line to each reference point is also referred to as a section.

1A is a flowchart illustrating an embodiment of a method for determining a line fault point according to the spirit of the present invention.

FIG. 1B is a detailed flowchart illustrating the method of identifying a line fault point of FIG. 1A by embodying equations applied as a transmission line fault point identification algorithm.

The illustrated line failure point detection method includes constructing a line constant DB composed of line constant information for each section of the target line (S120); obtaining measured values of voltage and current of the line at the time of failure (S140); Calculating a positive impedance by applying the measured value of the line at the time of the failure and each line constant value on the line constant DB (S150); For each section of the line, confirming a difference between the calculated positive impedance and the positive impedance described in the line constant DB (S160); and estimating the reference point of the section with the smallest difference as a failure point (S170).

As shown, in the step of configuring the line constant DB (S120), the line constant from the connection point to each reference installation is derived from the construction information on the reference installations (connection box, steel tower) of the target line. Step (S122); and virtually dividing a line between two consecutive reference installations into reference division points (S124), and linearly calculating a line constant from the connection point to each reference division point (S126). can

The line constant DB may have a form in which positive-segment impedance (Z ₁ ) and zero-segment impedance (Z ₀ ) from a connection point to each reference point are described with respect to a plurality of reference points on the line.

In the step of securing the voltage and current measurement values of the line at the time of failure (S140), the voltage and current measurement values at the time of failure are input from the protection relay installed at the connection point, or the failure record data is received from the line management server. can be done in this way. For example, in the case of the latter, fault record data measured for about 3 to 5 power frequency cycles before the protection relay operates may be transmitted from the line management server.

As described above, the shown line failure point detection method can be usefully applied to an underground 3-phase transmission line, and in the case of an underground 3-phase transmission line, the reference installation is a junction box of a 3-phase underground transmission line, and the construction The information includes ground handling information for each junction box. In the case of an overhead three-phase transmission line, the reference installation is a transmission tower, and the construction information may include material information or insulation/shielding coating information of a line between transmission towers.

Depending on the implementation, after the step S170, a step (S180) of outputting the fault point information, etc., expressed as a result of the execution of the above-described line fault point detection method, in the form of a display screen or a report may be further included. For example, in the step S180, the information on the specific reference point, which is the fault point estimated in the step S170, and the impedance difference (error) values of all reference points, as data that is the basis for calculating the specific reference point as the fault point, are graphed or It can be presented together in table form.

2 is a circuit diagram illustrating an aspect in which impedance appears at a connection point during a ground fault according to the spirit of the present invention.

In the situation of the illustrated circuit diagram, the current at the ground fault point is expressed in Equation 1 below.

The voltage at the connection point for normal/reversed/video is as shown in Equation 2 below.

From the current in Equation 1 and the voltage in Equation 2, the normal component impedance observed at the connection point at the time of failure is expressed in Equation 3 below.

In FIG. 2, since the failure occurred at the end point of the line indicated by Line, the denominator 14 [Ω] of the line constant K value and the fault point 14 [Ω] are the same. Generalizing this case, the algorithm of the present invention calculates the fault point by subdividing the K value according to the location in the line, compares it with Z ₁ used for the K value, and Z ₁ with the smallest error can be expressed as the fault point. there is.

FIG. 3 is a conceptual diagram showing the division of sections in the line failure point detection method according to the spirit of the present invention with respect to an underground transmission line.

In FIG. 3, eight junction boxes are arranged on one underground transmission line, and a partial line between two adjacent junction boxes is virtually divided into two, and a total of 17 reference points are designated from the left connection point to the right connection point. and a total of 18 sections from the left linkage point to each reference point and the right linkage point are defined. At this time, the line constants of each section are expressed as K ₁ to K ₁₈ .

The above line constants K ₁ to K ₁₈ are each from AS/S EBG to #1J/B, #2J/B, ..., BS/S EBG by using an underground transmission line line constant calculation program using construction information. The accumulated K value of is obtained, and a line constant DB can be configured by reflecting it.

The difference between the K value obtained for each junction box location and the K value obtained at the previous location is obtained, divided by n to be subdivided, and using this, the accumulated K value subdivided into n is obtained as shown in Equation 4 below, in FIG. The case where n to be subdivided is 2, and this is reflected.

There are 9 K values (K ₁ to K ₉ ) obtained in advance for each junction box location (+ next connection point) using the line constant calculation program, and the standard division by subdividing the section between each 2 junction boxes into 2 The number of K values obtained including the points is 18 (K' ₁ ~ K' ₁₈ ). In FIG. 3, it is revealed that the 18 K values (K' ₁ to K' ₁₈ ) are expressed as K ₁ to K ₁₈ .

Using the fault voltage, current, and subdivided 18 K values measured in A S/S, Equation 5 is applied to obtain 18 fault points Z1.

Here, the larger n and the larger the subdivision, the more accurate the fault point expression.

Equation 5 may be expressed as Equation 6 below for each of the n sections, and Equation 6 below is used in FIG. 1B.

That is, in the step of calculating the normal component impedance (S150) of FIG. 1, the normal component impedance may be calculated according to Equation 5 or Equation 6 above.

In step S160 of FIG. 1, as in the above-described process, the calculated positive impedance (Z _1n,fault ) obtained by deriving equations reflecting the measured values of voltage and current at the connection point in case of a fault to the line constant (Kn) and the The difference in the positive impedance (Z _1n ) described as a component of the line constant (Kn) can be confirmed, for example, as shown in Equation 7 below.

In step S170 of FIG. 1 , a reference point having the smallest value among n (= 18) error _n obtained according to Equation 7 (connected as a reference installation or reference division point) is estimated as a fault point.

4 is a block diagram illustrating an embodiment of a line failure point detection device according to the spirit of the present invention.

The illustrated line failure point determination device performs the line failure point determination method according to the idea of the present invention as described above in FIG. It can be implemented as an internal SW module of the device.

The illustrated line failure point determination device 100 includes a line constant DB 120 composed of line constant information for each section of the target line; a failure data acquisition unit 140 that acquires measured values of voltage and current of a line at the time of failure; and by applying the measured value of the line at the time of the failure and each line constant value on the line constant DB to calculate the constant impedance, and for each section of the line, the calculated constant impedance and the line constant DB It may include a fault point estimator 160 that checks the difference in the described positive impedance and estimates the reference point of the section with the smallest difference as the fault point.

The illustrated line constant DB 120 is an installation line constant DB in which the line constants from the connection point derived from the construction information on the reference installations (junction box, steel tower) of the target line to each reference installation are recorded ( 122); and a dividing line constant acquisition unit 124 that virtually divides a line between two consecutive reference installations into reference dividing points and obtains a dividing line constant calculated linearly from the connection point to each reference dividing point. ).

For example, the reference installation is a junction box of a three-phase underground transmission line and/or a steel tower of a three-phase overhead transmission line, and the construction information is grounding processing information for each junction box and/or line type information between transmission towers (eg, line material information or insulation/shielding coating information).

In the case of performing the line fault finding method according to the embodiment shown in FIG. 2, the fault point estimator 160 calculates the normal impedance according to Equation 5 or Equation 6. calculation unit 162; And the components of the normal component impedance (Z _1n,fault ) calculated by the calculation unit 162 for the normal component impedance for a plurality (n) sections of the target line and the line constant (K _n ) in the line constant DB. A comparison/failure point estimator 164 may include a comparison/failure point estimator 164 for confirming the difference in the normal component impedance (Z _1n ) described as Equation 7 and estimating a reference point of a small section with the smallest difference as a failure point.

The failure data acquisition unit 140 shown receives failure record data including voltage and current measurement values before the protective operation of the relay after failure recognition from the line management server 10 for operating and managing the target line. can be sent In another implementation, voltage and current measurement values at the time of failure may be received from a protection relay installed at the connection point.

The illustrated installation line constant DB 122 reads construction information for each installation (eg, junction box, steel tower) on the transmission line stored in the facility management server 20 that performs external transmission line facility management, and connects the connection point It is possible to obtain the line constants from to each standard installation.

Depending on the implemented location (server/computer type) of the shown line fault finding device 100 in the form of a SW module, in order to support the manager of the corresponding area, according to the execution of the line fault finding method according to the spirit of the present invention It may further include a result output unit 180 that outputs fault point information expressed as a result in the form of a display screen or a report. The result output unit displays information on a specific reference point, which is an estimated failure point, and impedance difference (error) values according to Equation 7 of all reference points as data that is a basis for calculating the specific reference point as a failure point. It can be presented together in table form.

After the measures for the failure are completed, the manager may input the location of the actual failure to the line failure point estimation device 100 . At this time, the line failure point estimation apparatus 100 does not belong to the estimated failure position, and the two reference origins adjacent to the input actual fault position do not belong to the estimated fault position, and the positive impedance for the two reference reference points adjacent to the actual fault position. If the difference between the impedance errors calculated by the calculating unit 162 and the impedance error calculated by the calculating unit 162 for the normal component impedance for the estimated fault location is greater than or equal to a predetermined reference value, a description error in the construction information of the target line It can be determined that the probability is high. In this case, the result output unit 180 may display/report the possibility of a description error in the construction information of the target line.

Hereinafter, simulation (simulation) performance results for examining the accuracy of the line failure point detection method according to the idea of the present invention will be described.

First, results of simulation (simulation) performed on the underground transmission line having the section configuration shown in FIG. 3 will be described.

The underground transmission line, which is a simulation target, is a 100% underground line, and includes XLPE2000 2.924km, one-end grounding, and an insulated junction box.

FIG. 5 is a graph showing positive-segment impedance and zero-segment impedance at each connection box (installation) point in FIG. 3 .

As shown, it can be seen that non-linear characteristics are exhibited at the installation location of the one-end grounding and the insulated junction box.

FIG. 6 is a simulation circuit diagram of an underground transmission line having the section configuration shown in FIG. 3 .

By applying the underground cable simulation circuit diagram shown in FIG. 6, in order to obtain V and I measured by the protection relay when a failure occurs at each junction box (J / B) point, underground cable modeling was performed using EMTP.

In order to examine the performance of fault point calculation according to the fault point identification method of the present invention on the simulation circuit diagram of FIG. 6, a 1-line ground fault is generated at 9 J/B locations in the model, V measured by the protective relay, I was obtained, and the results of calculating the failure point and the error with the point where the failure occurred in the model are shown in Table 2 through the fault point expression algorithm improved according to the spirit of the present invention.

In Table 2, the actual fault point on the simulation and the location of the fault point estimated according to the idea of the present invention match 100%, and the error of the positive impedances used in the process of finding the fault point according to the idea of the present invention is high. It is very low at the maximum of 3.7 in the strong point, and it can be seen that it is useful in the expression of the failure point.

Next, simulation (simulation) performance results for the complex transmission line in the form of underground + overhead line will be described.

FIG. 7 is a conceptual diagram illustrating division of sections in performing a fault point determination according to the spirit of the present invention with respect to a complex transmission line in the form of an underground + overhead line.

The complex transmission line, which is a simulation target, has a value of 2.924 km of line + ACSR 410sq 2B 5km as an underground + overhead complex line.

FIG. 8 is a graph showing positive-segment impedance and zero-segment impedance at each installation (connection box and steel tower) point in FIG. 7 .

As shown, it can be seen that each installation (junction box and steel tower), in particular, shows nonlinear characteristics at the installation location of one-end grounding and insulated junction box.

FIG. 9 is a simulation circuit diagram of a complex transmission line having the section configuration shown in FIG. 7 .

By applying the underground cable simulation circuit diagram shown in FIG. 9, in order to obtain V and I measured by the protection relay when a failure occurs at each junction box (J / B) and pylon point, EMTP was used to perform underground cable modeling. .

In order to examine the performance of fault point calculation according to the fault point identification method of the present invention on the simulation circuit diagram of FIG. 9, one line ground fault was generated at 9 J/B locations and 6 steel tower locations in the model, and the protective relay The results of calculating the failure point and the error with the point where the failure occurred in the model are shown in Table 4 through the acquisition of V and I measured in , and the fault point calculation algorithm improved according to the spirit of the present invention.

In Table 4, the actual fault point on the simulation and the location of the fault point estimated according to the idea of the present invention match 100%, and the error of the positive impedances used in the process of finding the fault point according to the idea of the present invention is high. In terms of advantages, it is very low at the maximum of 3.7 in the case of junction boxes and about 7.8 in the case of steel towers, so it can be seen that it is useful in the expression of the failure point. It can be assumed that the case of the underground line will be more accurate because the error is smaller than that of the connection of the underground line rather than the steel tower.

The above description is merely an example of the technical idea of the present invention, and various modifications and variations can be made to those skilled in the art without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are not intended to limit the technical idea of the present invention, but to explain, and the scope of the technical idea of the present invention is not limited by these embodiments. The protection scope of the present invention should be construed according to the claims below, and all technical ideas within the equivalent range should be construed as being included in the scope of the present invention.

The description of the present invention described above has been described with respect to transmission lines, considering that while construction information on grounding items is held/managed for power transmission lines in Korea, such construction information is not held/managed in distribution lines. However, it can also be applied to distribution lines that hold/manage construction information on grounding items, which, of course, also falls within the scope of the present invention.

100: line fault point expression device
120: line constant DB
122: installation line constant DB
124: division line constant acquisition unit
140: failure data acquisition unit
160: fault point estimation unit
162: normal component impedance calculation unit
164: comparison/failure point estimator
180: result output unit

Claims (13)

constructing a line constant DB consisting of line constant information for each section of the target line;
obtaining measured values of voltage and current of a line at the time of failure;
Calculating a normal component impedance by applying the measured value of the line at the time of failure and each line constant value on the line constant DB;
For each section of the line, checking a difference between the calculated positive impedance and the positive impedance described in the line constant DB; and
Step of estimating the reference point of the section with the smallest difference as the failure point
A line failure point expression method comprising a.
According to claim 1,
The step of constructing the line constant DB,
Deriving a line constant from a connection point to each reference installation from construction information on reference installations of the target line; and
Virtually dividing a line between two consecutive reference installations into reference division points, and linearly calculating a line constant from the connection point to each reference division point
A line failure point expression method comprising a.
According to claim 2,
The reference installation is a junction box of a three-phase underground transmission line,
Wherein the construction information includes grounding processing information for each junction box.
According to claim 1,
In the step of calculating the normal component impedance,
A line fault point finding method for calculating the normal component impedance according to the following equation.

According to claim 1,
In the step of securing the measured values of the voltage and current of the line at the time of the failure,
Receive voltage and current measurement values at the time of failure from the protective relay at the connection point,
A method for determining the fault point of a line that receives fault record data from the line management server.
According to claim 1,
The line constant DB,
A line failure point expression method in which positive and zero-segment impedances from a connection point to each reference point are described for a plurality of reference points on the line.
a line constant DB consisting of line constant information for each section of the target line;
a failure data acquisition unit that acquires measured values of voltage and current of a line at the time of failure; and
The measured value of the line at the time of failure and each line constant value in the line constant DB are applied to calculate the normal impedance, and for each section of the line, the calculated constant impedance and the line constant DB Fault point estimator that checks the difference in normal-sequence impedance and estimates the reference point of the section with the smallest difference as the fault point
Line failure point expression device comprising a.
According to claim 7,
The line constant DB,
An installation line constant DB in which the line constants from the connection point derived from the construction information on the reference installations of the target line to each reference installation are recorded; and
A division line constant acquisition unit that virtually divides a line between two consecutive reference installations into reference division points, and obtains a division line constant calculated linearly from the connection point to each reference division point.
Line failure point expression device comprising a.
According to claim 8,
The reference installation is a junction box of a three-phase underground transmission line,
The construction information includes grounding processing information for each junction box.
According to claim 7,
The fault point estimation unit,
A line fault point locating device including a constant impedance calculator for calculating the positive impedance according to the following equation.

According to claim 7,
The failure data acquisition unit,
A line fault point identification device that receives fault record data including voltage and current measurement values before the protective operation of the relay after fault recognition from the line management server.
According to claim 7,
Result output unit that outputs the expressed failure point information in the form of a display screen or report
Line failure point expression device further comprising a.
According to claim 12,
The result output unit,
A line fault point display device that outputs the possibility of description errors in the construction information of the target line.

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