JPH02216473A - Measuring instrument for fault position of balanced line - Google Patents

Abstract

PURPOSE:To exactly estimate a fault point from a difference of measured values of the input admittance before and after a fault by using a sinewave of 100Hz - 50kHz, and using a method for deriving the residual square sum of a measured value and a calculated value and averaging of data, etc. CONSTITUTION:An input admittance Y0 at the time when an additional impedance Z is added to a fault position 13 due to insulation deterioration, etc. is measured by the same frequency by an input admittance measuring part 3, and its data is stored in a measured data storage part 4 together with the measuring frequency. A difference detecting part 5 reads out the input admittance before and after the line is deteriorated and detects an input admittance difference Ym at every frequency, and an arithmetic part 7 reads out a balanced line constitution and generates a main line, reads out a propagation constant gamma, a characteristic impedance Z0 and line length of each line from a line constant storage part 6, and estimates the fault position 13 in which an input admittance difference Yc by an operation and the difference Ym by a measurement coincide with each other and the additional impedance Z.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention is utilized for measuring communication lines. INDUSTRIAL APPLICABILITY The present invention is used to measure the location and degree of failure when a communication line fails due to an open circuit, short circuit, insulation deterioration, flooding, or the like.

The present invention provides a balanced communication line (hereinafter referred to as "balanced line")
This invention relates to a device for estimating unequal impedance and its position when there is an impedance unequal point in the middle.

[Conventional technology]

Conventionally, a balanced line pulse tester has been used to determine the location of impedance imbalance points due to faults such as short circuits, open circuits, or insulation deterioration in the middle of communication lines. To explain the principle of position searching for impedance non-uniformity points using this conventional measuring device, first, a pulse is sent from the measuring device to the line, and a reflected wave that is reflected at the impedance non-uniformity point and returned to the measuring device is captured. If the pulse round trip time is the propagation speed of the T1 line as V, then the position of the impedance imbalance point is D = (1/2)
(TxV).

[Problem that the invention seeks to solve]

However, with this conventional measuring device, if the point of impedance inequity is close to the measurement point, the reflected wave cannot be identified because the reflected wave returns during the duration of the traveling pulse. Also,
If the impedance changes significantly, such as an open circuit or a short circuit, it is possible to detect the location, but even if the short circuit or open circuit occurs, the location is far from the measurement point, or if it is in the middle of the line. In the case of insulation deterioration, for example, when an impedance of about 10 to 500 Ω is added in parallel, the reflected pulse will attenuate and become smaller.
Its position and impedance cannot be detected.

In addition, to increase the positional resolution of impedance inequalities, it is possible to reduce the pulse width, but in this case the frequency component of the pulse becomes a high frequency component, and the amount of attenuation of the pulse increases, making it difficult for the measuring instrument to detect it. There was a drawback that the distance to the impedance non-uniformity point was small.

Furthermore, if there is a branch (multi-connection) on the line, even if there is a reflection from a point of impedance imbalance due to a fault in the line, this branch point is also a point of impedance imbalance, so the reflection from there will also be reflected. detected at the same time. In particular, when the distance between a branch point and a point of impedance imbalance due to a fault in the line is close, the reflected pulses overlap, making it difficult to identify the location of the fault.

As described above, one of the major reasons why there is a limit to the ability to search for fault locations in a line using a pulse tester is that the frequency components of the pulse waveform usually use frequency components with a large amount of attenuation, such as Hz or more.

The present invention prevents a part of the balanced line from short-circuiting, opening, insulation deterioration,
The purpose of the present invention is to provide a device that can correctly locate the location of a failure when a failure occurs due to flooding, etc., and can also estimate the insulation resistance value in the case of insulation deterioration and the capacitance value in the case of flooding. do.

[Means for solving problems]

The present invention uses a sine wave of about 100H2 to 50kHz, and includes a balanced line configuration storage unit that stores a connection configuration of a balanced line made of cables of the same type or different types, with or without branches, and the balanced line Input admittance Y before failure. X and the input admittance Y0 when an additional impedance Z is added to a part of the balanced line and a failure occurs at a single frequency or multiple frequencies, and the input admittance measuring section measures A measurement data storage unit that stores data together with the measured frequency, and a line constant storage unit that stores the measured frequency and the transmission constant T1 specific impedance Z0 and line length value 10 for each cable of the line for this frequency. Then, the input admittance before and after the line failure is read out for each frequency from the measurement data storage section, and the difference in input admittance Y is calculated.

and a difference detection unit that detects a transmission constant T1 for each cable, which sets a temporary fault position 11 and an additional impedance Z in the balanced line configuration read from the balanced line configuration storage unit, and reads out a propagation constant T1 for each cable from the line constant storage unit. Using the characteristic impedance ZO% and the line length io to convert the fault position 11 and the additional impedance Z, calculate the difference Y in input admittance before and after the line fails, and calculate the input admittance read from the difference detection section. The difference Y,
, and an output section that outputs the calculation result of this calculation section. It is characterized by

This calculation section: 1) Creates a main line, 2) Sets a temporary fault position and additional impedance Z on the main line for one main line, and calculates the input admittance difference YC by calculation on the complex plane and the input admittance by measurement. Find the square of the distance from the difference Y for each frequency, and calculate the sum of the squares of the distance (called the residual sum of squares) over all frequencies. Select a hypothetical fault position where the residual sum of squares is small; - Compare the residual sum of squares when selecting the fault position for all main lines, and calculate on the main line with the smallest residual sum of squares. It is possible to have the function of estimating the temporary fault position when the fault occurs as the true fault position.

[Effect]

The present invention uses a sine wave of about 100 Hz to 50 kHz to estimate the additional impedance and the position of an uneven point due to a fault from the difference in input admittance measurements after and before a fault occurs in a balanced line. .

This method differs from conventional technology in that because a low frequency can be used, attenuation is small and these can be estimated under advantageous conditions even if the failure point is far away or insulation has deteriorated.

〔Example〕

FIG. 1 is a block diagram of a bag/shelf according to an embodiment of the present invention.

This device includes a terminal 31 for connecting the balanced line 1 to be measured, and an input admittance measuring section 3 that measures the input admittance of the line 1 to be measured appearing at the terminal 31 at one or more frequencies. The results measured by this measuring section 3 are stored in the measured data storage section 4.

Here, this storage section 4 stores the input admittance Y measured by the measurement section before a failure with respect to a large number of balanced lines l to be measured with this device. 8 measurement results are stored for each measurement frequency.

Furthermore, for the plurality of balanced lines to be measured, as a first means of providing connection configurations including branch states, types of constituent cables, and their lengths from records, a balanced line configuration memory in which these connection configurations are stored in advance is provided. Part 2 is provided. Furthermore, for these multiple balanced lines to be measured, line length for each cable type! . As a second means for providing a standard characteristic impedance Z0 and a propagation constant T at the measurement frequency, a line constant storage section 6 is provided in which these are stored in advance.

Further, in this device, when the input admittance measured by the measurement unit 3 of the balanced line under test after a failure is Yo, the difference Ym=Yox Y.

A difference detection unit 5 calculates the distance to the fault position and the impedance added to the fault position based on the calculation results of the difference detection unit 5, parameters given from the balanced line configuration storage unit 2 and the line constant storage unit 6. , and an output section 8 that outputs the calculation result of the calculation section 7.

This calculation unit 7 assumes a distance 11 to a hypothetical fault position and an impedance Z added to that position for the balanced line to be measured, and calculates this distance! .

and means for calculating the difference Y0 between the input admittance after and before the failure of the balanced line using this impedance Z as a variable, and calculating the distance 11 and impedance Z such that this difference Ye matches the difference Ym. include.

First, we will explain how to calculate the input admittance of a balanced line and the principle behind how to find the fault location from the manual admittance.

To find the input admittance of a balanced line with branches and different types of cables, use the F matrix (Fundam
It is convenient to use the ``mental Matrix''. −
As an example, the case shown in FIG. 1 will be explained.

(1) Input admittance when there is no failure ■, arbitrarily divide the branch line and the main line (in Figure 1, the main line is shown as a straight line from the measurement end to the termination end).

(2) Find the input admittance Y when looking at the branch line terminal 14 from the branch point 12, and insert the F matrix at the branch point 12. The F matrix (F) of the line is expressed as follows (1), where the line length is 10, the propagation constant at a certain frequency is γ, and the characteristic impedance is 20. Here, r and Zo are complex numbers, and are usually expressed as 7=a+jβ, ZO= l Zo l 6J. j is an imaginary unit, e is the base of natural logarithm, and θ is the angle of impedance. The F matrix (F) of the branch line from the branch point 12 to the branch line terminal 14 is the product of the F matrices (F) of the two lines, since there is one dissimilar cable connection point 11 in the example of Fig. 1. . At this time, the input admittance Yb is C/C when the branch line terminal 14 is open.
When A is short-circuited, it becomes D/B, and the matrix (F) inserted at the branch point 12 is as follows.

■ F matrix of the main line including branch point 12 (F
). In the example in Figure 1, there are five Fs including branch point 12.
M) Just calculate the product of IJ Fuchs F). The input admittance is C/A when the main line terminal 15 is open.
, becomes D/B when short-circuited.

(2) Human power admittance when there is a failure ■ Model so that the assumed failure location 13 is on the main line (in Figure 1, the main line is shown as a straight line from the measurement end to the termination end).

■ Represent the fault position (disconnection, short circuit, insulation deterioration, etc.) as one F matrix, insert this into the F matrix (F) of the line when there is no fault position 13, and perform ■ in (1) above.
You can calculate it according to.

The fault position 130F matrix (F) is the fault position 13
are expressed by a series impedance Zl or a parallel impedance z2, respectively.

Above, we have shown how to calculate the input admittance of a balanced line. Next, the principle of determining the fault location from the input admittance will be explained.

The measured input admittance difference Y represents one point on the complex plane. On the other hand, the calculated input admittance difference Yc can be calculated using Impedance z1 becomes infinite, or in the case of a short circuit, the parallel impedance Z2 becomes 0, so the fault position is one variable, and in the case of insulation deterioration, the fault position and the magnitude of the additional impedance (degree of insulation deterioration) are the two variables. Becomes a variable.

Therefore, in case of open or short circuit, the propagation constant γ,
If there is no error in the characteristic impedance Z0 x line length 10 and the measurement system, the fault location 13 can be determined correctly, and if there is an error in any of the above, the difference Y in human admittance measured on the complex plane, It is possible to specify the fault position 13 where the calculated input admittance difference Yc most closely matches. Furthermore, in the case of insulation deterioration, even if there are errors in the propagation constant T1, characteristic impedance Z0, line length 10, and measurement system, the fault position 13 and the magnitude of the additional impedance can be identified. Note that the above error will affect the estimation accuracy of the fault location 13.

In order to specifically explain the principle of determining the fault location, an example of calculating the input admittance when the failure mode is insulation deterioration will be shown below.

Figure 2 shows the balanced line configuration used in the calculations, where line 1a has a conductor diameter of 0.4 mm and line length 16 km x 1 m line 1b.
The conductor diameter is 9.5mm, the line length is 0.7km, and the line is 1c%.
Both ld and 1e have a conductor diameter of 0.5 mm and a line length of 0.
．． It is lkm.

When the position of the additional impedance z2, which indicates the degree of failure deterioration, is changed along the main line (0 to 2.3 km) in Figure 2, the input admittance before and after the additional impedance z2 is added is as follows: Difference Y.

is obtained for each measurement frequency f and shown on a complex plane as shown in FIG. In Figure 3, 22 = lOkΩ,
The locations where the additional impedance Z is added are marked every 23 km. In addition, the measurement frequency f is IKH
Hz, 2KHz, 5KHz, and 10Hz. It can be seen from FIG. 3 that as the fault position increases, the angle of deviation of the admittance difference Yc rotates clockwise from 0, and that as the measurement frequency f increases, this rotation angle increases.

Next, when the measurement frequency is held constant and the position of the additional impedance Z2 is varied along the main line in FIG. 2, the difference Y in input admittance. is determined for each additional impedance z2 and shown on the complex plane as shown in FIG. In this figure, the measurement frequency f is 1 KHz, and the positions where the additional impedance Z2 is added are marked every 0.23 km.

It can be seen that as the additional impedance Z2 increases, the arcs become smaller in almost similar shapes.

In this way, each line length β0x frequency f1 of the balanced line configuration
and the propagation constant T and characteristic impedance Z at this frequency f. If Z2 is known, one point on the complex plane represents only one additional impedance Z2 and its additional position Il. Therefore, by calculating the difference Y in input admittance before and after the additional impedance Z2 is added to the line at a moderate frequency f, it can be seen that the only combination of additional impedance Z2 and its addition position 11 can be found by calculation. .

Above is the difference Y of input admittance as a measured value.

It was found that the fault location can be estimated by calculation by calculating . However, when finding the fault location practically, it is necessary to calculate the propagation constant r1 characteristic impedance ZO1 line length! ! 0x and measurement system errors must be taken into account. Below are the propagation constant γ, characteristic impedance z0, and line length. is called a database error, and the measurement system error is called a reading error, and these two types of errors will be explained.

(1) Database error The cable's secondary constant (transmission constant T1 characteristic impedance Z) is determined by the cable manufacturer, manufacturing date, and
Different pairs show different values even within the same cable.

However, in order to accurately estimate the location of a fault in a line, it is necessary to measure the quadratic constant for all pairs in the cable before the fault occurs, or for each individual cable if different types of cables are connected. There is a need. When a failure occurs, the quadratic constant of the failed line itself must be used. However, in practice, creating such a database is extremely difficult.

Under these circumstances, in order to estimate the location of a line failure, it is necessary to use standard line quadratic constants for each cable type. At this time, the problem is how much error (database error) between the faulty line and the quadratic constant of the standard line results in an error when estimating the line failure location. If the error is large, countermeasures need to be taken. As a countermeasure to this problem, a method that evaluates based on the difference in human input admittance before and after a failure (hereinafter referred to as the finite difference method) is effective, compared to a method that evaluates based on the input admittance after a line failure (hereinafter referred to as the non-differential method). Explain that.

Frequency f = 1 Hz, line length 10 km, conductor diameter 0
．． 5mm, no branch point, additional impedance Z2 = 1
For a line with insulation deterioration of 0Ω, the line capacitance C is a standard value α=0.1692Np/km.

β=0.1732 rad/km.

z, =754.300, θ = -0,7736rad when +10% change, dimodal number α = 0.177
6Np/km.

β=0.1814 rad/km.

First, FIG. 5 shows an example of calculation using the non-differential method, assuming that the change in Z, =719.25Ω, θ=-0,7748rad is a database error. - The mark is the measured value of the degraded line when there is a database error, and the mark X is the calculated value using the standard value of the quadratic constant for estimating the fault location. For example, if the fault location is 21an, there is one point on the complex plane (2' of the mark
km point) is given, and the fault position 11 passing through this point and the additional impedance z2 are determined by calculation. In this example, 11=0.0976kmS22
= 13.40, resulting in a large fault position error.

Next, an example of calculation using the difference method is shown in FIG. - The mark is the measured value of the degraded line when there is a database error, and the mark X is the calculated value using the standard value of the quadratic constant for estimating the fault location. For example, as in Fig. 5, for a 2 km fault, only one point (2 km point marked with .) is given on the complex plane, and by calculation, the fault position l passing through this point and the additional impedance Z are calculated.
, will be sought. It can be immediately seen from this figure that the fault location error is much smaller than the non-differential method. In fact, when the fault location l and additional impedance Z2 are determined, 1+ = 2.039tan, Z2 = 10.22Ω.

In this way, it can be said that the influence of database errors can be considerably alleviated by using the differential method.

(2) Reading error When measuring the input admittance of a line, the measured value inevitably includes a reading error. For the balanced line configuration shown in Figure 2, the additional impedance Z2 = 10Ω, the frequency f = IKHz, and the relationship between the fault location and fault location estimation error is shown in Figure 7, using the reading error as a parameter. In this figure, the reading error is 0.2%, 0.5%, 0.0%.
2%, and the differential method (indicated by D) and the non-differential method (indicated by A) are shown. For example, the reading error is 0.2
In the case of the differential method, it is written as 0.2% (D). In addition, for the balanced line configuration in Figure 2, additional impedance Z2 = 10Ω, reading error 0.2%, difference method, frequency as a parameter, and an example of finding the relationship between the fault location and position estimation error is shown in Figure 8. As shown in the figure. In this figure, the frequency is IKHz.
, 2KHz, 5KHz, and 10KHz.

The following can be seen from FIGS. 7 and 8.

■ When the fault location becomes distant, the fault location estimation error increases rapidly.

■ As the frequency increases, the fault location estimation error increases. This tendency is particularly large for distant failures.

■ Since the differential method is a non-differential method, the fault location estimation error is large. The reason for this is that the differential method measures twice, once before and after the failure.

Therefore, in order to reduce the fault position estimation error due to the reading error, a low frequency may be used in the non-differential method.

Above, in (1) and (2), the influence of database error and reading error on fault location estimation error has been explained. When actually estimating the fault location, these two are combined. First of all,
Comparing the differential method and the non-differential method, it is true that the non-differential method is more advantageous in the case of reading errors, but the differential method is significantly more advantageous in the case of database errors, so overall the differential method is more advantageous. is more advantageous.

Next, considering frequency, if the difference method is used as described above, the influence of database errors will be reduced, so it is only necessary to consider the influence of reading errors. Therefore, it is sufficient to use a low frequency, but it is not always better to use a low frequency. In other words, when the frequency is about 100 Hz or less, the input admittance becomes small and the reading accuracy of the measuring instrument decreases, so the frequency used should be between 100 Hz and 50 Hz.
A frequency of about KHz is preferable, and particularly when the fault location is far away, it is preferable to use a lower frequency within this frequency range.

So far, we have explained the principle by which a line fault position can be estimated by calculation and that it is preferable to use a frequency of about 100 Hz to 50 KHz using the differential method in order to reduce the error in estimating the fault position.

The operation of the apparatus for estimating the additional impedance ring at the line fault position and its position will be described below with reference to FIG.

A connection configuration of a balanced line 1 having branches and consisting of different types of cables is stored in a balanced line configuration storage unit 2. Then, the balanced line 1 is connected to the connection terminal 31 of the input admittance measuring section 3, and the human admittance Y before the balanced line 1 deteriorates. X
is measured by the input admittance measuring section 3 at a single frequency or at a plurality of frequencies, and the data is stored in the measured data storage section 4 together with the measured frequencies. The frequency is 1
00Hz to 50Kf (about Z is preferable. At the same time,
Measured frequency, propagation constant r1 characteristic impedance Z0 for each cable for each frequency, and line length! .

is stored in the line constant storage section 6.

Next, the input admittance measurement section 3 measures the human input admittance Y0 when the additional impedance Z is added to the fault location 13 due to insulation deterioration, etc., at the same frequency as above, and stores the measured data together with the measured frequency. It is stored in section 4.

The difference detection section 5 reads the input admittance before and after the line deteriorates from the measurement data storage section 4, and detects the difference Y, =Yox Y-, in the input admittance for each frequency. The calculation unit 7 reads the difference Y from the difference detection unit 5 for each frequency, and reads the balanced line configuration from the balanced line configuration storage unit 2 to create a main line. The propagation constant γ of the line is
The characteristic impedance Z0 and the line length 10 are read out, and the fault position 13 where the calculated difference Yc in the human input admittance matches the measured input admittance difference Y, and the additional impedance Z at that position are determined for each frequency. presume. When the failure mode of the failure position 13 is open or short circuit, only the failure position 13 is estimated. This calculation result is outputted at the output section 8. Note that the balanced line 1 may have no branches or may be a single type of cable.

In this device, since the fault position and additional impedance Z can be determined for each frequency, the accuracy of estimating the fault position can be improved by sweeping the frequency. This is because if an abnormal value is accidentally taken in at one frequency due to noise or the like, there is a risk that the fault location will be estimated significantly incorrectly. The fault location is estimated by frequency sweep as follows. - Provide a temporary fault position and additional impedance Z on the main line (if the failure mode is open or short-circuit, only the fault position 13 is provided). (2) Find the square of the distance between the calculated input admittance difference Y and the measured input admittance difference Y on the complex plane for each frequency. ■Find the sum of the squares of the distances (called the residual sum of squares) over all frequencies. ■Repeat the steps from ■ to ■ above. (2) Estimate the temporary fault position where the residual sum of squares is the smallest as the calculated fault position 13 (in the case of insulation deterioration, the fault position and additional impedance). ■Regenerate the main track. Note that the above methods (1) to (2) can be applied even when there is only one frequency.

Further, as shown in FIG. 1, in a line where there is a branch point 12, a plurality of main lines are generated, and a fault position is estimated for each main line. That is, a plurality of apparent failure positions are estimated. Some of these are clearly contradictory, for example, the main line is 5km long, but it is 5.5km long.
If it is presumed that this is the case, it is easy to remove it. For other lines, for each main line created, compare the minimum residual sum of squares (residual sum of squares of the point where the fault location was estimated) mentioned above, and select the main line with the smallest residual sum of squares. An effective method is to assume that the main line is correct (the fault position is on the main line) and estimate the tentative fault position calculated using the main line as the true fault position.

FIG. 9 shows an example in which this effectiveness was confirmed through experiments.

In this example, the conductor diameters are all o, 4 mm, and the s frequency is 1.
8 points between ~56.23 KHz, failure mode is open. When there is one branch point, two main lines (a) and (ra) are created, and these main lines are shown as straight lines.

For each, the estimated value of the fault location and the minimum residual sum of squares when estimating this location were determined. (a), (
b) Comparing the minimum residual sum of squares for the two cases,
It can be seen that From this result, the fault location is on the main line (5), and the fault location at this time is estimated to be 3.601 km, which agrees well with the fact.

Next, we will show an example of estimating the fault location using this device. The line configuration was as shown in Fig. 10, the diameter of all conductors was 0.4 mm, a branch point was provided at the 3 km point, and the 3 and 6 km points were designated as failure locations. Table 1 shows the estimation results of the fault location. From the tree table, in the case of open and short circuits, the estimation error varies greatly depending on the frequency with the non-differential method, making estimation difficult, whereas with the finite difference method, the variation of the estimation error with frequency is small, making it difficult to estimate the fault location. It turns out it's easy. On the other hand, in the case of insulation deterioration of 10Ω, it is extremely difficult to estimate the fault location using the non-differential method, which confirms the advantage of the differential method. Note that the error is 400 m for l KHz using the non-differential method, but this means that the estimated position is at the farthest end of the track (4 km).
This means that the fault location estimation error cannot be said to be small.

〔Effect of the invention〕

As explained above, the present invention has the advantage that it is possible to estimate the location and additional impedance of open or short circuit faults and insulation deterioration faults that are far from the measurement point, which was difficult with conventional pulse testers. have In addition, since the fault location and additional impedance can be determined at multiple frequencies, the accuracy of the estimated value can be improved by calculating the residual sum of squares between the measured value and the calculated value, or by averaging the data. It also has the advantage of being able to

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an apparatus according to an embodiment of the present invention. FIG. 2 is a diagram showing the configuration of a balanced line to explain how a fault location can be determined by measuring and calculating input admittance. Figure 3 shows the difference Yc in the input admittance before and after the additional impedance is added when the position of the additional impedance of 10Ω is changed along the main line (0 to 2.3 km) shown in Figure 2. The measurement frequency IKHz, 2
A diagram obtained on a complex plane obtained at each frequency of KHz, 5KHz, and 10KHz. Figure 4 shows the difference Yc in input admittance calculated for each additional impedance when the measurement frequency is IK)lz and the position of the additional impedance is changed along the main line in Figure 2, and is shown on the complex plane. . 5 and 6, the frequency is I KHz and the line length is 1.
The figure which shows the result of calculating the fault position estimation of the insulation deterioration balanced line of 0 km, conductor diameter 0.5 body, no branch point, and additional impedance of 10Ω by the non-differential method and the finite difference method. Figure 5 is for the non-differential method, and Figure 6 is for the differential method. Figure 7 shows the balanced line configuration diagram shown in Figure 2, with an additional impedance of 10 Ω, a frequency of I KHz, reading errors of 0.2%, 0.5%, and 0.02%, and the fault location and fault location. The figure which calculated the relationship with an estimation error for the difference method and the non-differential method. Figure 8 shows the balanced line m configuration shown in Figure 2, with an additional impedance of 10Ω, a reading error of 0.2%, and a frequency of 1K.
Hz, 2KHz, 5KHz, 10 llz
The figure shows the relationship between the fault location and the location estimation error using the finite difference method. FIG. 9 is a diagram illustrating that even if there is one branch point on the line, the fault location can be determined by comparing the minimum residual sum of squares obtained for each main line. FIG. 10 is a diagram showing the configuration of a balanced line when the fault location is estimated using this device. 1... Balanced line, 2... Balanced line configuration memory section,
・Manual admittance measuring section, 4... Measurement data storage section, 5... Difference detection section, 6... Line constant storage section, 7.
...Calculating section, 8...Output section, 11...Dissimilar cable connection point, 12...Branch point, 13...Failure position, 14
... Branch line terminal, 15... Main line terminal, 31
···Connecting terminal. Yi side g (S) o 1kHz + ZkHz 5kHz MU + 0k)lx Shoulder iris diagram Fumata part (S) 10kQ +20ku 50k11 Shoulder rotation-Yu distance II (km) 0.2°/, (A) + , O5' l*(A) 6.0
2'/, (A) 4.2"/4 (C13X, 05"+
6+01mm, 02”1.(D)W37 Figure 11 Distance (km) Mouth 1kHz + 2k14z o 5kHza l
0kHz Straw diagram (B) (+)) Iris rotation Q diagram

Claims (1)

[Claims] 1. A terminal (31) for connecting a balanced line under test, and an input admittance measuring section (3) for measuring the input admittance of the line under test appearing at this terminal at one or more frequencies; In a balanced line failure location measuring device comprising a measurement data storage unit (4) for storing measurement results measured by the measurement unit, the storage unit (4) stores information about a plurality of balanced lines to be measured by the measurement unit. Input admittance Y_0 measured before failure
a first means (2) in which the measurement results of _x are stored for each measurement frequency, and for the plurality of balanced lines to be measured, providing connection configurations including branch states, types of cables that constitute them, and their lengths from the record; a second means (6) for providing a standard characteristic impedance Z_0 and a propagation constant r at the measurement frequency with respect to the line length l_0 for each type of cable for the plurality of balanced lines to be measured; and the balanced line to be measured after a failure. When the input admittance of the line measured by the measurement unit (3) is Y_0, a difference detection unit (5) calculates the difference Ym=Y_0_x−Y_0; and the calculation result of this difference detection unit (5), the first Means (2)
and a calculation unit (7) that calculates the distance to the fault position and the impedance added to the failure position based on the parameters given from the second means (6), and an output unit (7) that outputs the calculation results of this calculation unit. 8), the calculation unit (7) assumes a distance l_1 to a temporary fault position and an impedance Z added to that position for the balanced line to be measured, and sets this distance l_1 and this impedance Z as variables. The method is characterized in that it includes means for calculating the difference Y_c between the input admittance after and before the failure of the balanced line, and calculating the distance l_1 and impedance Z such that this difference Y_c matches the difference Ym. Balanced line fault location measuring device.