JPH10300808A - Fault location method for transmission line - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify a structure for the fault location and automatically measure an arrival time difference between a direct wave and the first reflected wave. SOLUTION: A surge sensor 4 installed at one end of a transmission line 2 is used to take a surge waveform for low pass filter operation. Times for an intersection between the surge waveform to which the low pass filter operation is given and a positive/negative preset surge wave detecting comparison level are detected in sequence and a time difference between a time for the intersection at the first peak and a time for the intersection at the second peak is detected as a time difference T1 between an arrival time for the direct wave of a surge and an arrival time for the first reflected wave of the surge. A time T2 required for the surge to be reciprocally moved between one end and the other end of the transmission line 2 and a surge propagation speed (v) are used to calculate a distance Lx between one end of the transmission line 2 and a failure point where the surge is entered in accordance with Lx= v×(T2-T1)/2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention uses a surge sensor installed at one end of a transmission line to obtain a surge waveform generated at the time of a lightning strike on the transmission line, and a surge direct wave from the accident point is applied to one end of the transmission line. The present invention relates to a method for locating a fault point on a transmission line, which measures a time difference between a time when the first wave arrives at the point of arrival and a time when the first reflected wave from the other end of the surge transmission line arrives and locates a fault point from the time difference.

[0002]

2. Description of the Related Art In the event of a lightning strike on a transmission line connecting two substations, a pulse radar system, a surge reception system, an impedance system, and the like are known as conventional systems for locating an accident point where a surge has entered a transmission line. However, these methods are all methods of monitoring the fault point, transmitting and receiving pulses at both ends of the transmission line, and locating the fault point from voltage and current waveforms at commercial frequencies.

[0003]

However, in the conventional method, it is necessary to install fault point detecting devices at both ends of the transmission line, and the configuration for locating the fault point is complicated. With respect to such a problem, the applicant of the present application can locate the fault point only by installing the fault point detecting device at one end of the transmission line, and can simplify the configuration for fault location. A method for locating faults on transmission lines has been proposed (Japanese Patent Application No. 6-151904).

In this method of locating a fault on a transmission line, a surge waveform generated at the time of a lightning strike on the transmission line is acquired by using a surge sensor installed at one end of the transmission line, and a direct wave of a surge from the fault point is transmitted to the transmission line. the first reflected wave and measure the time difference T ₁ of the the time has been reached, measured beforehand surge between one end and the other end of the advance power transmission line is reciprocally by the other end of the transmission line time and the surge which reaches the end of the from the propagation velocity v directly with the waves in the transmission line time T ₂ and surge and the first reflected wave arrival time difference T ₁ Prefecture, the distance L _X of the accident point to which one end and the surge of the transmission line has penetrated

[0005]

Equation 3 is a method in which orientation the fault point by calculating according to _{L X = v × (T 2} -T 1) / 2. However, in the method of locating the fault point using the surge waveform as described above, the acquired actual lightning waveform includes many waveforms including a noise and a resonance waveform. It is difficult to identify the direct wave of the surge from the accident point and the first reflected wave from the other end of the transmission line.Therefore, it is difficult to identify the arrival time difference between the direct wave and the reflected wave, and it is not possible to establish a waveform measurement algorithm. The arrival time difference could not be automatically obtained from the waveform. Therefore, the operator watches surge waveform actually estimates the arrival time of the direct wave and the first reflected wave, further estimates the arrival time difference T ₁ from their arrival times is substituted into Formula 3 above In this way, the accident point is located.

However, in the method of estimating the arrival time difference T ₁ by looking at the surge waveform and locating the accident point, the automatic measurement of the arrival time difference T ₁ is impossible, and the orientation value differs depending on the person performing the orientation. there were. Therefore, an object of the present invention is to provide an accident point locator only by providing an accident point detection device at one end of a transmission line, thereby simplifying the configuration for locating the accident point, and directly It is possible to automatically measure the difference between the arrival time of the wave and the first reflected wave, and all the fault points can be automatically located from the acquisition of the surge waveform. It is to provide a possible transmission line fault location method.

[0007]

According to a first aspect of the present invention, there is provided a transmission line fault point locating method, comprising: obtaining a surge waveform generated at the time of a lightning strike in a transmission line by using a surge sensor installed at one end of the transmission line; A low-pass filter operation is performed on the waveform, and the time of the intersection of the surge waveform subjected to the low-pass filter operation and the predetermined comparison level for positive / negative surge wave detection is sequentially detected, and the time of the intersection of the first peak and the second intersection are detected. th detected as the time difference T ₁ of the the time the first reflected wave reaches by the other end of the time and the surge of power lines direct wave reaches the surge penetrated the time difference in the transmission line between the time of intersection of the peak, the distance L _X of the accident point to which one end and the surge of the transmission line has entered is calculated according to Formula 3.

According to this method, a surge waveform generated at the time of a lightning strike in a transmission line is acquired, and the time at which the direct wave of the surge arrives and the time at which the first reflected wave of the surge arrives based on the acquired surge waveform. detecting a time difference T _1, since one end and the surge of the transmission line is calculated according to Formula 3 the distance L _X of the accident point has penetrated, to one end of the transmission line only by providing the detection device of the fault point including surge sensor in, orientation of the fault point, i.e. obtains distances L _X of the accident point to which one end and the surge of the transmission line has entered, it is possible to perform orientation of the fault point.

Further, a low-pass filter operation is performed on the acquired surge waveform, and the time of the intersection of the surge waveform subjected to the low-pass filter operation and a predetermined positive / negative comparison level for surge wave detection is sequentially detected. since the first reflected wave time and of the second time and surge direct wave surge time difference between the time of intersection of the peak reaches an intersection of the peak is detected as a time difference T ₁ of the the time has been reached, the direct wave And the arrival time difference between the first reflected wave and the first reflected wave can be automatically measured, and it is possible to automatically measure the arrival time difference between the direct wave and the first reflected wave, and to locate the fault point automatically from the acquisition of the surge waveform. By doing so, it is possible to eliminate individual differences among persons to be located, and to accurately locate an accident point.

The method for locating a fault on a transmission line according to claim 2 is the method for locating a fault on a transmission line according to claim 1.
The surge waveform subjected to the low-pass filter operation is differentiated, and the absolute value of the derivative value of the surge waveform at the time of the intersection of the low-pass filter-calculated surge waveform and the predetermined positive / negative comparison level for surge wave detection is a predetermined arrival wave. It is characterized in that it is regarded as an arrival wave when it is higher than the detection comparison level, and is regarded as noise when it is lower than a predetermined arrival wave detection comparison level.

According to this method, the arrival wave in the surge waveform and the noise can be distinguished, and erroneous orientation due to the noise can be prevented. According to a third aspect of the present invention, there is provided a transmission line fault point locating method, wherein a surge waveform generated at the time of a lightning strike on a transmission line is acquired by using a surge sensor installed at one end of the transmission line, and a low-pass filter operation is performed on the surge waveform. The time of appearance of the positive and negative peaks of the surge waveform subjected to the low-pass filter operation is sequentially detected, and the time difference between the first peak time and the second peak time is transmitted by the direct wave of the surge entering the transmission line. detected as the time difference T ₁ of the the time the first reflected wave by the other end of the transmission line time and the surge which reaches the one end of the wire has reached the distance L _X of the accident point to which one end and the surge of the transmission line has penetrated It is characterized in that it is calculated according to [Equation 3].

According to this method, the surge waveform generated at the time of the lightning strike on the transmission line is acquired by using the surge sensor installed at one end of the transmission line, and the time at which the direct surge wave arrives based on the acquired surge waveform. detecting a time difference T ₁ of the the time the first reflected wave surge arrives and, the distance L _X of the accident point to which one end and the surge of the transmission line has entered Formula 3
Calculate according to the following formula, simply install an accident point detection device including a surge sensor at one end of the transmission line,
That obtains distances L _X of the accident point to which one end and the surge of the transmission line has entered, it is possible to perform orientation of the fault point.

A low-pass filter operation is performed on the acquired surge waveform, and the appearance times of positive and negative peaks of the surge waveform subjected to the low-pass filter operation are sequentially detected.
Th and time of the peak because a direct wave surge time difference between the time of the second peak is detected as a time difference T ₁ of the the time the first reflected wave time and the surge which reaches the end of the transmission line has reached The arrival time difference between the direct wave and the first reflected wave can be obtained automatically, and the arrival time difference between the direct wave and the first reflected wave can be automatically measured. This makes it possible to eliminate the individual differences among the persons who perform the localization, thereby enabling accurate localization of the accident point.

According to a fourth aspect of the present invention, there is provided the transmission line fault point locating method according to the third aspect.
The surge waveform subjected to the low-pass filter operation is differentiated, and is reached when the absolute value of the derivative value of the surge waveform at the appearance time of the positive and negative peaks of the surge waveform subjected to the low-pass filter operation is greater than a predetermined arrival wave detection comparison level. And is regarded as noise when it is smaller than a predetermined arrival wave detection comparison level.

According to this method, the arrival wave in the surge waveform and the noise can be distinguished, and erroneous orientation due to the noise can be prevented.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. [First Embodiment] A method for locating a fault on a transmission line according to a first embodiment of the present invention will be described with reference to FIGS.

FIG. 1 is a schematic view of an apparatus for locating an accident point when a lightning strike occurs on a power transmission line. In FIG. 1, 1A and 1B are substations respectively, 2 is a substation 1
A transmission line connecting between A and 1B and subject to fault point monitoring. For example, one fault point monitoring section is between two substations 1A and 1B. 3 indicates a lightning strike, and the tip of the arrow indicates the accident point 7. A surge sensor 4 is installed at one end of the transmission line 2 (in this example, a substation 1A) and includes a surge current transformer 4A and a surge transformer 4B. 5 is lightning strike 3
This is a waveform measuring device that can measure and record the waveform of the surge that has entered the transmission line 2 by the substation 1A.
Reference numeral 6 denotes an arithmetic processing unit which reads the arrival time difference between the direct wave from the fault point 7 and the first reflected wave from the other end of the transmission line 2 (the substation 1B) from the acquired surge waveform to locate the fault point. 1A.

FIG. 2 shows a state of propagation and reflection of a surge wave when the power transmission line 2 receives a lightning strike 3 in the system shown in FIG. 1. The vertical direction of the paper indicates the time axis, and the arrow 8
A and 8B show the progress of the surge waveform. In FIG.
When a lightning strike 3 is applied to the transmission line 2, a surge sensor 4
At the one end (substation 1A) of the transmission line 2 where the surge waveform first arrives as a direct wave (first wave) from the fault point 7, and then the surge waveform from the fault point 7 is transmitted. It is reflected at the other end of the electric wire 2 (substation 1B) and arrives as the first reflected wave (second wave), then the first wave is reflected at one end of the transmission line 2 (substation 1A), and further transmitted The second wave is reflected at the other end (substation 1B) and arrives as the third wave, and the fourth wave and thereafter arrive in the same manner.

As described above, one end of the transmission line 2 (the substation 1
A surge wave that sequentially arrives at A) is detected by a surge sensor 4 provided at one end of the transmission line 2 (substation 1A), and measured and recorded (acquired) by a waveform measuring device 5. The surge wave (voltage wave or current wave) measured and recorded by the waveform measuring device 5 has a waveform as schematically shown in FIG. In FIG. 3, the time difference from the arrival time of the direct wave (first wave) to the arrival time of the first reflected wave (second wave) is T ₁ (μs), and the time difference from the arrival time of the direct wave (first wave) is The time until the arrival time of the second reflected wave (third wave), that is, the time required for the surge to reciprocate between one end and the other end of the transmission line 2 is represented by T ₂
(Μs).

Here, using the above times T ₁ and T ₂ ,
The location of accident point 7, that is, one end of transmission line 2 (substation 1
The procedure for obtaining the distance from A) to the accident point 7 will be described with reference to FIG. In FIG. 4, L _X (k
m) is the distance from the fault point 7 of the transmission line 2 to one end (substation 1A) of the transmission line 2 where the surge sensor 4 is installed, L _Y (k
m) is the distance from the fault point 7 of the transmission line 2 to the other end of the transmission line 2 (substation 1B).

The surge propagation speed in the transmission line 2 is expressed as v (km / km / km).
μs), the surge propagation velocity v becomes

[0022]

## EQU4 ## It is represented by v = 2 × (L _X + L _Y ) / T ₂ . The time difference T ₁ is

[0023]

T ₁ = (2L _Y + L _X ) / v−L _X / v = 2L _Y / v Therefore, the distance L _X is

[0024]

[6] can be determined by _{L X = v × (T 2} -T 1) / 2. That is, when the lightning strike 3 occurs, the time difference T ₁ is obtained from the surge waveform, and the above-described calculation of [Equation 6] is performed based on the time T ₂ and the surge propagation speed v and the time difference T ₁ obtained in advance. , The accident point 7 can be located.

The time difference T ₁ between the time when the direct wave of the surge entering the transmission line 2 reaches one end of the transmission line 2 and the time when the first reflected wave from the other end of the transmission line 2 of the surge arrives is as follows. So as to ask automatically. That is, using the surge sensor 4 installed at one end of the transmission line 2, a surge waveform generated at the time of a lightning strike on the transmission line 2 is acquired, and a low-pass filter operation (for example, a moving average operation) is performed on the surge waveform, and a low-pass filter is performed. The time of the intersection of the surge waveform subjected to the filter operation and the predetermined comparison level for positive / negative surge wave detection is sequentially detected, and the time difference between the time of the intersection of the first peak and the time of the intersection of the second peak is determined. the time difference T ₁ of the above.

If the length of the transmission line 2 is known, the surge propagation speed v can be calculated according to [Equation 4]. However, when the fault detecting device including the surge sensor 4 is installed, an artificial lightning test or a test at the substation 1A is performed in advance. for switching surge by the breaker operation measures the time T _2, previously calculated. Here, the algorithm for locating the accident point described above is shown in FIG.
6 and FIG. 7 will be described. 6 (a), 6 (b) and 6 (c) show transmission line lengths.
FIGS. 7A, 7B, and 7C are waveform diagrams showing three-phase surge voltage waveforms obtained when an example of a lightning strike actually occurred on a 6 km transmission line, and FIGS. It is a waveform diagram which shows the surge voltage waveform of three phases after performing the low pass filter operation by the moving average method with respect to a voltage waveform.

First, surge waveform data as shown in FIG. 6 is obtained by sampling (step S).
1). Next, a low-pass filter operation equivalent to passing the obtained surge waveform sampling data through a low-pass filter, for example, a moving average operation, is performed to obtain a surge waveform from which high-frequency components are removed as shown in FIG. 7 ( Step S2).

Next, the peak value of the peak at which the peak value is maximum is obtained from the surge waveform on which the low-pass filter operation has been performed (step S3), and a differential operation is performed on the surge waveform after the low-pass filter operation. A waveform is obtained (step S4). In the A-phase surge waveform of FIG. 7A, the peak value at which the peak value is the maximum is 561A.
(At 19.9 μs).

Next, a positive / negative comparison level for surge wave detection is calculated and set based on the peak value of the peak at which the peak value in the surge waveform is maximum (step S5). For example, the comparison level for surge wave detection is set to ± 1 of the peak value of the peak.
Set to / 4. When the peak value of the maximum peak is 561A, the comparison level for surge wave detection is 140A. Next, the time of the intersection of the surge waveform subjected to the low-pass filter operation and the comparison level for surge wave detection is detected (step S6).

Next, at the time of the above intersection, only the point of the positive differential value is stored at the positive intersection, and only the point of the negative differential value is stored at the negative intersection (step S7). This means that the intersection of the leading edge portion of the waveform peak and the comparison level for surge wave detection is stored. Next, based on the calculation result of step S4, the arrival wave detection comparison level (absolute value) is set based on the maximum value of the differential value of the differential surge waveform (step S8). In this case, the arrival wave detection comparison level is set to, for example, about 80% of the maximum value of the differential value.

Next, it is determined whether or not the absolute value of the differential value stored in step S7 is larger than the arrival wave detection comparison level (step S9). If the decision result in the step S9 is Y
In the case of ES, the waveform peak is regarded as the arrival wave (step S10), and in the case of NO, the waveform peak is regarded as noise (step S11).

If the decision result in the step S9 is YES, the appearance times of the first wave (direct wave) and the second wave (reflected wave) are detected and stored (step S12). In FIG. 7, at the intersection between the surge waveform and the comparison level for surge wave detection, the one corresponding to the direct wave (the first intersection) is 19.
The one that is at 3 μs and corresponds to the first reflected wave (the second intersection) is at 63.3 μs. Note that the peak of the first reflected wave has the opposite polarity to the peak of the direct wave, and these two times are stored.

Next, the arrival time difference T ₁ between the first wave (direct wave) and the second wave (reflected wave) is calculated (step S).
13). In this case, the time difference T ₁ is

[0034]

[Equation 7] T₁= 63.3-18.3 = 44.0 μs. Next, based on the arrival time difference,
, That is, the calculation of [Equation 6] is performed to determine whether
From the fault to the fault point 7 is calculated (step
S14). In the transmission line 2, the surge propagation speed v is 0.2
94 km / μs, and T _Two= 106 μs, [number
6], L_X= 9.1 km.

The surge propagation speed v was obtained as follows based on [Equation 4]. That is,

[0036]

## EQU8 ## v = 2 × 15.6 / 106 = 0.294 (km / μs) The distance L _X was calculated as follows.
That is,

[0037]

Equation 9] _{L X = 0.294 × (106-44)} / 2 ≒ 9.1 (km) On the other hand, in the case of an example of a torpedo accident actually occurs in the transmission line of the transmission line route length 15.6km described above According to the results of the patrol, a lightning strike occurred in phase A at a point 9.4 km from one end of the transmission line 2 (substation 1A side). Therefore, the distance L _X obtained by the calculation is -300 m compared to the inspection result.
, And it became clear that sufficient accuracy was obtained.

According to the transmission line fault point locating method of this embodiment, the surge waveform generated at the time of the lightning strike in the transmission line 2 is acquired and acquired using the surge sensor 4 installed at one end of the transmission line 2. From the surge waveform, a time difference T ₁ between the time when the direct wave of the surge that has entered the transmission line 2 reaches one end of the transmission line 2 and the time when the first reflected wave from the other end of the transmission line 2 of the surge reaches is detected. simply calculates the distance L _X of the accident point to which one end and the surge of the transmission line 2 has penetrated according [6], a surge from one end of transmission line 2 is able to obtain the distance L _X to the fault point invaded Therefore, it is possible to locate the fault point only by providing the fault point detection device including the surge sensor 4 at one end of the transmission line 2, thereby simplifying the configuration for fault location. As a result,
The installation work of the accident point detecting device is simplified, and the number of devices is reduced, so that the cost is reduced. In addition, since the fault point is located based on the surge waveform, high-speed operation is possible.
Therefore, the use application is extended to a traveling wave relay that can operate at high speed. Further, a low-pass filter operation is performed on the acquired surge waveform, the time of the intersection of the surge waveform subjected to the low-pass filter operation and the predetermined positive / negative comparison level for surge wave detection is sequentially detected, and the intersection of the first peak is detected. The time difference between the time of the second peak and the time of the intersection of the second peak is determined by the time when the direct wave of the surge entering the transmission line 2 reaches one end of the transmission line 2 and the first reflected wave by the other end of the transmission line 2 of the surge. since but detected as the time difference T ₁ of the the time has been reached, it is possible to automatically determine the arrival time difference between the direct wave and the first reflected wave, the accident as possible the automatic measurement of the direct wave and the arrival time difference of the first reflected wave All points can be automatically located from the acquisition of the surge waveform, eliminating individual differences among persons to be located, making it possible to accurately locate an accident point.

Further, the surge waveform subjected to the low-pass filter operation is differentiated, and the absolute value of the differential value of the surge waveform at the time of the intersection of the surge waveform subjected to the low-pass filter operation and a predetermined positive / negative comparison level for surge wave detection. When the arrival wave is larger than the predetermined arrival wave detection comparison level, the arrival wave is regarded as noise, and when the arrival wave is smaller than the predetermined arrival wave detection comparison level, the arrival wave is regarded as noise. Misorientation due to noise can be prevented.

[Second Embodiment] A method of locating a fault on a transmission line according to a second embodiment of the present invention will be described with reference to FIG. The method for locating accidents on this transmission line is as follows:
Although the point of calculating the distance L _X according [6] is the same as the first embodiment, the arrival time difference T as the pretreatment
_The algorithm for obtaining 1 is different from that of the first embodiment.

The direct wave of the surge that has entered the transmission line 2
At the time when it reaches one end of line 2 and at the other end of
Time difference T from the time when the first reflected wave arrives₁Is
Automatically ask as below. That is, power transmission
Using the surge sensor 4 installed at one end of the wire 2, the transmission line
Obtain the surge waveform generated during the lightning strike in
Low-pass filter operation (eg, moving
Averaging) and the low-pass filter
The time of appearance of the positive and negative peaks of the waveform
The time difference between the time of the peak and the time of the second peak is
The above time difference T ₁And

If the length of the transmission line 2 is known, the surge propagation speed v can be calculated according to [Equation 4]. However, the artificial lightning test or the substation 1A beforehand when installing the fault point detecting device including the surge sensor 4 is performed. for switching surge by the breaker operation measures the time T _2, previously calculated. Here, the algorithm for locating the accident point described above is shown in FIG.
6 and FIG. 7 will be described.

First, surge waveform data as shown in FIG. 6 is obtained by sampling (step T).
1). Next, a low-pass filter operation equivalent to passing the obtained surge waveform sampling data through a low-pass filter, for example, a moving average operation, is performed to obtain a surge waveform from which high-frequency components are removed as shown in FIG. 7 ( Step T2).

Next, the appearance times of the waveform peaks of the surge waveform after the high-frequency component is removed by performing the low-pass filter operation are stored in order of the absolute value (step T3).
This is because the polarity of the peak of the surge waveform is opposite to the polarity of the waveform peak of the direct wave from the accident point 7 and the polarity of the reflected wave from the other end of the transmission line 2. Next, a differential operation of the surge waveform after the low-pass filter operation is performed to obtain a differential surge waveform (step T4).

Next, the arrival wave detection comparison level (absolute value) is set based on the maximum value of the differential value of the differential surge waveform (step T5). Next, it is determined whether or not the absolute value of the differential value at the appearance time of each waveform peak of the surge waveform stored in step T3 in the differential surge waveform obtained in step T4 is larger than the arrival wave detection comparison level (step T6).

If the decision result in the step T6 is YES, the waveform peak is regarded as a reaching wave (step T7),
If NO, the waveform peak is regarded as noise (step T8). When the determination result in step T6 is YES, the appearance times of the first wave (direct wave) and the second wave (reflected wave) are detected and stored (step T9). FIG. 7 (a)
Then, for example, there are peaks at the time point of 19.9 μs and the time point of 63.9 μs, and the peak at the time point of 63.9 μs is −
205A.

Next, the arrival time difference between the first wave (direct wave) and the second wave (reflected wave) is calculated (step T1).
0). In the case of FIG.

[0048]

T ₁ = 63.9-19.9 = 44.0 μs Next, the fault point 7 is located based on the arrival time difference, that is, the calculation of [Equation 6] is performed to calculate the length of the power transmission line 2 from one end of the power transmission line 2 to the fault point 7 (step T11). In the transmission line 2, as described above, the surge propagation speed v is 0.294 km / μs, and T ₂ = 106
μs, and when the operation of [Equation 6] is performed, L _X = 9.1 km, as in the first embodiment.

On the other hand, the above-mentioned transmission line path length of 15.6 km
In the case of an example of a lightning strike that actually occurred on the transmission line No. 3, according to the patrol result, a lightning strike occurred on the phase A at a point 9.4 km from one end of the transmission line 2 (the substation 1A side). The distance L _X obtained by the calculation is -3 compared to the inspection result.
The difference almost coincided with the difference of 00 m, and it was clear that sufficient accuracy was obtained.

According to this embodiment, the surge waveform generated at the time of the lightning strike on the transmission line 2 is acquired by using the surge sensor 4 installed at one end of the transmission line 2, and the surge waveform invading the transmission line 2 is obtained from the acquired surge waveform. The time difference T ₁ between the time when the direct wave of the surge reaches the one end of the transmission line 2 and the time when the first reflected wave from the other end of the transmission line 2 arrives is detected, and one end of the transmission line 2 and the surge are detected. by invading the distance L _X of the accident point just calculated according [6], a surge from one end of transmission line 2 is able to obtain the distance L _X to the fault point which has entered, thus the one end of the transmission line 2 The fault point can be located simply by providing a fault point detecting device including the surge sensor 4, and the configuration for fault point location can be simplified. As a result, the installation work of the accident point detection device is simplified, and the number of devices is reduced, so that the cost is reduced. In addition, since the fault point is located based on the surge waveform, high-speed operation is possible. Therefore, the use application is extended to a traveling wave relay that can operate at high speed.

Further, a low-pass filter operation is performed on the acquired surge waveform, and the appearance times of the positive and negative peaks of the surge waveform subjected to the low-pass filter operation are sequentially detected.
The time difference between the time of the second peak and the time of the second peak is determined by the time when the direct wave of the surge entering the transmission line 2 reaches one end of the transmission line 2 and the first reflection of the surge by the other end of the transmission line 2. and detects a time difference T ₁ of the the time the wave arrives, it is possible to automatically determine the arrival time difference between the direct wave and the first reflected wave, as a possible automatic measurement of the direct wave and the arrival time difference of the first reflected wave The location of the accident point can be automatically performed from the acquisition of the surge waveform, eliminating individual differences among the persons to be located, making it possible to accurately locate the accident point.

Further, the surge waveform subjected to the low-pass filter operation is differentiated, and the absolute value of the differential value of the surge waveform at the appearance time of the positive or negative peak of the surge waveform subjected to the low-pass filter operation is determined by a predetermined arrival wave detection comparison level. When it is larger than the predetermined arrival wave detection comparison level, the arrival wave is regarded as noise, and when it is smaller than the predetermined arrival wave detection comparison level, the arrival wave and noise in the surge waveform can be distinguished from each other, thereby preventing misorientation due to noise. it can.

[0053]

According to the method for locating a fault point on a transmission line according to the first aspect, the distance from one end of the transmission line to the fault point where the surge has entered can be obtained. It is possible to locate an accident point only by providing a detection device for the accident point including the accident point, thereby simplifying the configuration for locating the accident point. As a result, the installation work of the accident point detection device is simplified, and the number of devices is reduced, so that the cost is reduced. In addition, since the fault point is located based on the surge waveform, high-speed operation is possible. Therefore, the use application is extended to a traveling wave relay that can operate at high speed. In addition, the arrival time difference between the direct wave and the first reflected wave can be automatically obtained, and the arrival time difference between the direct wave and the first reflected wave can be automatically measured. This makes it possible to eliminate the individual differences among the people who are locating, and to accurately locate the accident point.

According to the method for locating a fault point on a transmission line according to the second aspect, the arrival wave in the surge waveform and noise can be distinguished, and erroneous localization due to noise can be prevented. According to the method for locating a fault on a transmission line according to claim 3,
The distance from one end of the transmission line to the accident point where the surge invaded can be obtained.Therefore, the accident point can be located simply by installing an accident point detection device including a surge sensor at one end of the transmission line. The configuration for locating points can be simplified. As a result, the installation work of the accident point detection device is simplified, and the number of devices is reduced.
Become cheap. In addition, since the fault point is located based on the surge waveform, high-speed operation is possible. Therefore, the use application is extended to a traveling wave relay that can operate at high speed.

Further, the arrival time difference between the direct wave and the first reflected wave can be automatically obtained, and the arrival time difference between the direct wave and the first reflected wave can be automatically measured. All of them can be performed automatically, eliminating the individual differences among the persons to be located, making it possible to accurately locate the accident point. According to the transmission line fault point locating method according to the fourth aspect, it is possible to distinguish between the arrival wave in the surge waveform and the noise, and to prevent erroneous localization due to the noise.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of an apparatus for locating an accident point when a lightning strike occurs on a transmission line.

FIG. 2 is a schematic diagram showing a state of propagation and reflection of a surge wave when a lightning strike is applied to a transmission line in the method for locating a fault on a transmission line according to the first embodiment of the present invention.

FIG. 3 is a reflection waveform diagram of a surge wave.

FIG. 4 is a schematic diagram showing a distance between both ends of a transmission line and an accident point.

FIG. 5 is a flowchart showing an algorithm for detecting a time difference between a direct wave and a first reflected wave according to the first embodiment of the present invention.

FIG. 6 is a waveform chart showing surge voltage waveforms for three phases acquired at the time of the occurrence of the actual lightning strike in the first embodiment of the present invention.

FIG. 7 is a waveform chart showing surge voltage waveforms for three phases after a low-pass filter operation in the first embodiment of the present invention.

FIG. 8 is a flowchart showing an algorithm for detecting a time difference between a direct wave and a first reflected wave according to the second embodiment of the present invention.

FIG. 9 is a flowchart showing an algorithm for detecting a time difference between a direct wave and a first reflected wave in the prior art.

[Explanation of symbols]

 1A, 1B Substation 2 Transmission Line 3 Lightning Strike 4 Surge Sensor 5 Waveform Measuring Device 6 Arithmetic Processing Unit 7 Accident Point

Claims (4)

[Claims] 1. Using a surge sensor installed at one end of a transmission line, obtain a surge waveform generated at the time of a lightning strike on the transmission line, perform a low-pass filter operation on the surge waveform, and perform the low-pass filter operation. The time of the intersection of the generated surge waveform and the predetermined comparison level for positive / negative surge wave detection is sequentially detected, and the time difference between the time of the intersection of the first peak and the time of the intersection of the second peak is transmitted to the transmission line. detecting the direct wave of invading surges as the time difference T ₁ of the the first time the reflected wave arrives by the other end of the transmission line of the surge and the time it reaches the end of the transmission line, one end of said transmission line When the time required for the surge to reciprocate between the other ends is T ₂ and the surge propagation speed is v, the distance L _X between one end of the transmission line and the accident point where the surge has penetrated is given by ] L _{X v × (T 2 -T 1)} / 2 fault point locating method of the transmission line, characterized by calculating in accordance with. 2. A surge waveform subjected to a low-pass filter operation is differentiated, and a differential value of the surge waveform at a time of an intersection between the surge waveform subjected to the low-pass filter operation and a predetermined positive / negative comparison level for surge wave detection is calculated. 2. The fault point of a transmission line according to claim 1, wherein when the absolute value is greater than a predetermined arrival wave detection comparison level, the arrival wave is determined, and when the absolute value is smaller than the predetermined arrival wave detection comparison level, the arrival wave is regarded as noise. Orientation method. 3. Using a surge sensor installed at one end of a transmission line, obtain a surge waveform generated during a lightning strike on the transmission line, perform a low-pass filter operation on the surge waveform, and perform the low-pass filter operation. The appearance time of the positive and negative peaks of the generated surge waveform is sequentially detected, and the time difference between the time of the first peak and the time of the second peak is detected by a direct wave of the surge that has entered the transmission line at one end of the transmission line. the first reflected wave is detected as a time difference T ₁ of the the time has been reached, the time required between the one end and the other end of the transmission line to surge back and forth by the other end of the transmission line of the surge and the arrived time Is defined as T ₂ and the surge propagation speed is defined as v, and the distance L _X between one end of the transmission line and the accident point where the surge has penetrated is given by: L _X = v × (T ₂ −T ₁ ) / 2 Fault point locating method of the transmission line, wherein the door. 4. A surge waveform subjected to a low-pass filter operation is differentiated, and an absolute value of a differential value of the surge waveform at a time of appearance of a positive or negative peak of the surge waveform subjected to the low-pass filter operation is used to detect a predetermined arrival wave. 4. The method according to claim 3, wherein the arrival wave is regarded as an arrival wave when the level is larger than the comparison level, and as a noise when the level is smaller than the predetermined arrival wave detection comparison level.