JP2005130566A - Method of deducing lightning conductor damage - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for deducing the number of conductive wires, forming a lightning conductor that has been broken due to lightning strike and deducing the point of broken conductive wire on the lightning conductor. <P>SOLUTION: The deducing method includes a step (a) which acquires a distance between the point of lightning strike and a steel tower hoisting a lightning conductor which allows a lightning strike current to flow to the ground; a step (b) which extracts the steel tower within the prescribed range of distance and a lightning strike that occurs; a step (c) which acquires a discharge potential quantity from the discharge current waveform of the extracted lightning strike; a step (d) which acquires the relationship between the discharge potential quantity of lightning strike and the number of broken wires forming the lightning conductor, based on the thickness and kind of the lightning conductor hoisted by the extracted steel tower; and a step (e) which estimates the number of broken wires of the lightning conductor hoisted by the extracted steel tower, by collating the discharge potential quantity acquired by the step of acquiring the discharge potential quantity with the relationship. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for estimating the number of breaks caused by a lightning strike of a wire that forms a lightning protection wire and the position on the lightning protection wire where the wire is broken.

  Generally, a lightning conductor formed by twisting a plurality of wires is laid on the power transmission line in order to prevent lightning strikes directly on the power line. The lightning protection line is suspended above the power line, and when a lightning strike occurs, the lightning strike current flows to the ground through the steel tower. However, even if lightning falls on the lightning conductor as originally intended, the wire forming the lightning conductor may melt and break due to the lightning current.

  When the wire of the lightning conductor is cut in this way, it hangs down and comes into contact with the power line, and the current flowing through the power transmission line flows into the lightning line, resulting in a major problem that power supply cannot be performed.

  Further, the lightning protection line cannot receive all lightning, and when a lightning of a predetermined size (for example, 20 kA or more) occurs, this lightning falls to the power line. The lightning strike current of lightning that has fallen on the power line thus reaches the steel tower through the power line, and may flow into the power line through the insulator that suspends the power line, thereby damaging the insulator. When the insulator is damaged in this way, the electric power flowing through the electric power line flows over the insulator to the steel tower side, so that the electric power cannot be stably supplied and the power transmission must be stopped. The power transmission line is composed of a first line that constantly sends power in consideration of such a power stoppage due to lightning, and a second line that sends power when a failure or the like occurs in the first line. ing.

  As a means for protecting the insulator from the lightning strike current, there is an apparatus called an arc horn in which metal bars extending from both ends of the insulator are abutted at a predetermined interval. According to this, the lightning current that has flowed through the power line or directly into the tower is short-circuited (hereinafter referred to as “flash”) between the metal rods of the arc horn, not on the insulator, and flows into the power line. Can prevent damage.

  If this arc horn is installed, damage to the insulator can be prevented, but if the lightning strike current is flashed by the arc horn, the transmission current flowing through the power line crosses between the metal rods of the arc horn and goes to the tower side. It becomes easy to flow. This causes a “ground fault” in which the transmission current flows from the power line through the arc horn to the ground. In addition, when the lightning current value is large, a plurality of power lines “ground fault” in one steel tower, thereby “short-circuiting” between the power lines, or in the case of a larger lightning current value, “Ground fault” and “short circuit” also occur in the power lines on the two lines.

  When a “short circuit” or “ground fault” occurs as described above, power cannot be stably supplied, and power transmission on the transmission line is stopped. This is called “thunder accident”. In addition, “accident transmission line” refers to the transmission line in which a lightning accident has occurred, “an accident tower” refers to a steel tower that has caused a short circuit or ground fault, which is the cause of a lightning accident, and “a lightning strike that causes a short circuit or ground fault in an accident tower” Accident lightning.

  When a lightning accident such as that described above occurs, it is necessary to check the accident tower and damage status, and to perform repair work as soon as possible. Therefore, it is important to accurately identify the accident tower. Also, if the location of the accident lightning can be identified for each lightning accident, it is possible to determine the range where many accidental lightnings are occurring, and take reasonable lightning accident countermeasures by installing arresters only on the steel towers within that range. Can be taken.

  Conventionally, a lightning location system (hereinafter referred to as “LLS”) is used to identify accident lightning and accident towers. Specifically, the location of lightning strikes (for example, longitude and latitude) and time that occurred within a time range of about 1 second or about 1 minute of the lightning accident occurrence time due to “LLS”, and the position closest to the lightning strike The tower to be identified is identified as the accident tower.

  LLS detects electromagnetic waves generated by lightning strikes using orthogonal loop antennas, and observes them at multiple (for example, 6) lightning strike direction measurement slave stations and lightning strike direction measurement slave stations that measure the direction of lightning strikes and peak values of magnetic fields. And a lightning strike position analyzing device for obtaining a lightning strike position and a lightning strike current value based on the obtained data.

  The lightning strike position analyzer uses the triangulation principle to determine the location of lightning strikes from the orientation data observed at the two lightning strike direction measuring stations, and based on the peak value of the magnetic field and the distance from the lightning strike point to the lightning strike direction measuring station. The electric shock current value is obtained and the data is stored in the computer.

  In LLS, a lightning occurrence time can be accurately grasped according to Japanese standard time by using a satellite clock using GPS.

  And if a lightning accident occurs, the accident tower and the accident lightning are estimated from the information obtained by the above LLS, and the accident situation such as ground fault is confirmed based on this, and the lightning conductor around the accident tower is confirmed. The state of wire breakage can be examined. However, unless a lightning strike that falls on a lightning line causes a lightning accident, it is impossible to grasp the state of breakage of the wire due to the lightning strike.

  Therefore, in the past, assuming such a case, patrols are performed once a month. However, if the number of wire breaks is small, the wire breakage status cannot often be confirmed by visual inspection at the time of patrol.In recent years, in order to ascertain the lightning wire breakage status of the lightning protection wire from the sky using a helicopter. High-definition photography is performed. However, there is a problem that this work is very expensive.

  From the research on lightning and the results of lightning accidents, there is a view that the breakage of the wire of the lightning wire occurs due to lightning strikes with a large amount of charge. Lightning strikes with a large amount of charge occur frequently in winter and are called “long wave tail lightning” because of the long discharge duration (for example, 100 msec). The observation of this long wave tail lightning is considered to have not been carried out since then since only the observation records of the 1960s and 1980s remain. Therefore, long wave tail lightning has been observed to elucidate the causal relationship between the breakage of the lightning wire and the long wave tail lightning.

  For the observation of long wave tail lightning, a long wave tail lightning observation device that measures changes in electric and magnetic fields generated when a lightning strike occurs is used. When detecting a lightning strike, the long wave tail lightning observation device measures an electric field and a magnetic field every 1 μs and accumulates data obtained by continuing the measurement for a predetermined time (for example, 1 second) in a computer. From the change in electric field and magnetic field measured by this long wave tail lightning observation device, a discharge current waveform due to lightning can be obtained. The lightning occurrence time and the discharge duration can be accurately grasped in accordance with the Japanese standard time by using a satellite clock using GPS.

  In the following patent document, the lightning light signal peak is detected and the direction of lightning strike is specified from the incident direction, and at the same time, the timekeeping operation starts at the time of lightning incident, and the timekeeping operation is stopped at the time of lightning sound detection. Is described, and a “lightning strike position measuring device” is described in which a lightning strike position is estimated by obtaining a distance from the product of the time difference and the sound velocity.

Japanese Patent Laid-Open No. 06-186325

  However, in the method for identifying accident lightnings and accident towers by LLS, it is impossible to grasp that the wire forming the lightning protection wire has broken, and therefore the number of breaks and the broken position cannot be estimated. Further, the above “lightning strike position measuring device” only estimates the position where a lightning strike occurs, and cannot estimate the number of wire breakage of lightning conductors and the position where the wire breaks, similar to LLS.

  An object of the present invention is to provide a method for estimating the number of breaks caused by lightning strikes of a wire forming a lightning protection wire and the position on the lightning protection wire where the wire is broken.

  According to the lightning line damage estimation method of the present invention, (a) a step of obtaining a distance between a steel tower over which the lightning line for passing a lightning current to the ground and a lightning strike position is provided, and (b) the distance is predetermined. (C) a step of obtaining a discharge charge amount from a discharge current waveform of the extracted lightning strike, and (d) a lightning wire over which the extracted steel tower is suspended. And (e) the discharge charge obtained in the step of obtaining the discharge charge amount, based on the type and thickness of the lightning, and determining the relationship between the discharge charge amount of the lightning strike and the number of breaks of the wire forming the lightning protection wire. Estimating the number of wire rod breakage of the lightning conductor in which the extracted steel tower is aerial by comparing the amount with the relationship.

  In a specific aspect of the present invention, in the step (b), when there are a plurality of steel towers within the predetermined range with respect to one lightning strike, the steel tower closest to the lightning strike is extracted.

  In addition, when it is estimated that the wire rod of the lightning conductor has been broken by the collation of (e), between the steel tower subject to the collation and the steel tower that suspends the lightning conductor on both sides of the steel tower. The wire is estimated to be broken.

  The relationship (d) can be obtained in advance based on the type and thickness of the lightning conductor.

  According to the lightning line damage estimation method of the present invention, when the distance between the steel tower over which the lightning line is suspended and the position where the lightning strike is within a predetermined range, the type and thickness of the lightning line over which the steel tower is suspended. On the basis of the lightning discharge charge amount and the number of breaks of the wire forming the lightning protection wire, and comparing this with the lightning discharge charge amount within the predetermined range, The number of wire breaks can be estimated. Thereby, since the damage situation of a lightning conductor can be grasped | ascertained easily, the expense concerning the inspection of a lightning conductor can be reduced significantly. In this case, when there are a plurality of steel towers within a predetermined range for one lightning strike, it is preferable to extract the steel tower closest to the lightning strike.

  Further, when it is estimated that the wire rod of the lightning conductor has been broken by the collation, the wire rod is broken between the steel tower subject to the collation and the steel tower over which the lightning wire is suspended on both sides of the steel tower. Can be estimated.

  Moreover, it is preferable to obtain | require previously the relationship between the discharge charge amount of a lightning strike, and the fracture | rupture number of the wire which forms the said lightning conductor based on the kind and thickness of a lightning conductor.

  FIG. 1 is a flowchart of a lightning conductor damage estimation method according to an embodiment of the present invention, showing calculation processing performed by a computer.

  First, the computer reads LLS lightning strike data (step [hereinafter referred to as ST] 1). Specifically, when one or a plurality of lightning strikes occur, it is preferable that the lightning occurrence position (for example, coordinates), the occurrence time, and the lightning strike current value are automatically received from the LLS. FIG. 2 shows the location of lightning strikes that occur around a certain lightning protection line based on lightning strike information received from the LLS. Hereinafter, the basic concept of the lightning conductor damage estimation method of the embodiment will be described.

  Next, the distance between the steel tower over the lightning protection line and the lightning occurrence position included in the lightning strike information read in ST1 is calculated (ST2). Specifically, the distance between the two may be calculated based on the coordinates of the steel tower previously known as the facility information and the coordinates of the lightning occurrence position included in the lightning strike information received from the LLS in ST1.

  From the calculation result of ST2, it is determined whether or not there is a steel tower within a predetermined distance (for example, within 1 km) from the lightning strike position (ST3). FIG. 3 illustrates the state at this time and clearly shows the positional relationship between the steel tower and the lightning strike position by drawing a circle with a predetermined radius (eg, 1 km) centered on the lightning strike location. Is.

  If the determination in ST3 is “NO”, that is, if the steel tower is not included in the circle shown in FIG. 3, it is estimated that there is no lightning strike that may have broken the wire of the lightning arrester, and the process returns to ST1.

  If the determination in ST3 is “YES”, that is, if there is a steel tower in the circle shown in FIG. 3, the steel tower and a lightning strike with the center of the circle as the generation position are extracted (ST4). In FIG. 3, three steel towers are included in a circle centered on a lightning occurrence position at the upper center and lower center of the drawing. Here, an upper lightning strike in the figure is “T1”, and a lower lightning strike is “T2”.

  Next, among the towers extracted in ST4, the tower closest to the extracted lightning strike is extracted (ST5). Specifically, the distance between the two obtained in ST2 may be compared. FIG. 4 shows a state where one steel tower closest to each of the lightning strikes T1 and T2 is extracted. Hereinafter, a steel tower that is within a predetermined distance (for example, within 1 km) from a lightning occurrence position and is closest to each lightning occurrence position is referred to as a “neighboring steel tower”. 3 and 4, three steel towers are extracted for one lightning strike. For example, when only one steel tower is extracted for one lightning strike, the steel tower is regarded as a nearby steel tower. That's fine.

  Next, the electromagnetic field waveform data is read (ST6), and the process proceeds to the next step. Specifically, electromagnetic field waveform data based on changes in the electric and magnetic fields generated at the same time as the occurrence of each lightning strikes T1 and T2 extracted in ST4 may be read from the long wave tail lightning observation device.

  Here, the long wave tail lightning observation device should start data acquisition when there is a certain electric field change so as not to acquire data such as electric field change caused by the current flowing through the transmission line. . Specifically, data acquisition may be started when a large electric field change (for example, 1000 kHz) is detected in a short time that occurs during a lightning strike.

  After reading the electromagnetic field waveform data in ST6, the discharge charge amount of each lightning strike T1, T2 extracted in ST4 is obtained (ST7). Specifically, from the discharge current waveform based on the electromagnetic field waveform data obtained in ST6 and the lightning strike current values of lightning strikes T1 and T2 included in the LLS lightning strike data obtained in ST1, the lightning strike current value of each lightning strike T1 and T2. May be integrated with the discharge duration. As a result of the calculation, for example, the discharge charge amount of the lightning strike T1 is 20C, and the discharge charge amount of the lightning strike T2 is 50C.

FIG. 5 is an example of a lightning discharge current waveform in which the electromagnetic wave waveform data obtained in ST6 is associated with the lightning strike current value included in the LLS lightning strike data obtained in ST1. In the embodiment, in order to facilitate the calculation of the lightning discharge charge amount, an approximation of the discharge current waveform is used. Specifically, the origin of the graph is the point where the straight line passing through the point of 10% and 90% of the peak value on the actual waveform obtained in ST6 intersects the time axis, and the lightning current value is the maximum value “Ip”. The approximate waveform was obtained by dividing the time difference from when the peak value indicated 10% on the actual waveform to 90% by dividing the time “t ₁ ” until indicated by “0.8” by 0.8. .

Further, when the long wave tail lightning observation device is set to continuously record the electromagnetic field waveform data for 1 second, the electromagnetic field waveform data is interrupted when the lightning strike duration exceeds 1 second. . In this case, the time “t ₂ −t ₁ ” from when the lightning strike current value shows the maximum value to when it reaches half the maximum value (50%) is discharged from when the lightning strike current value shows the maximum value. A waveform (indicated by a chain line in the figure) is assumed by estimating that it is half of the time until the process ends.

  Next, the lightning protection performance of the lightning wire over which the nearby steel tower extracted in ST5 is collated with the discharge charge amount of each lightning strike T1, T2 obtained in ST7 (ST8). Specifically, based on the type and thickness of the lightning conductor included in the tower equipment information stored in the computer, the relationship between the lightning discharge charge amount and the number of breaks of the wire forming the lightning conductor. And compare this with the amount of lightning discharge charge.

  FIG. 6 is an example of a database showing the relationship between the discharge charge amount of lightning strikes and the number of breaks of the wire forming the lightning protection wire overlaid by the nearby steel tower extracted in ST5. In the embodiment, based on the type and thickness of the lightning conductor, the calculation processing by the computer is obtained in advance by determining the relationship between the discharge charge amount of the lightning strike and the number of breaks of the wire forming the lightning conductor. We are trying to speed up. In the example, two nearby steel towers were extracted in ST5. However, the lightning wire in which both steel towers are suspended has a line type of “AC”, an overall thickness of “70 mm”, and a wire rod thickness of “3.5 mm. / 1 ”and the number of wire rods is“ 7 ”.

  Then, since the discharge charges of lightning strikes T1 and T2 are 20C and 50C, when the lightning resistance performance of the corresponding lightning protection lines, that is, the data in the thick frame of the database (FIG. 6) is collated, the lightning strike T1 with a discharge charge of 20C The lightning resistance of the lightning protection wire exceeds the lightning resistance, and for the lightning strike T2 with a discharge charge of 50C, the discharge charge amount "40-50C" corresponding to three wire breaks and the number of wire breaks four It can be seen that this corresponds to the corresponding discharge charge amount “45 to 55C”.

  FIGS. 7 and 8 are materials used to determine the relationship between the lightning discharge charge amount and the number of wire breaks (FIG. 6), and show the lightning resistance performance of the electric wires, which has been found from experimental results. In the embodiment, based on these materials, a database indicating the relationship between the lightning discharge charge amount and the number of broken wire rods is created for all steel towers carrying lightning conductors.

  The equipment damage situation is estimated from the result of collation in ST8 (ST9). Specifically, it is presumed from the collation of ST8 that for lightning strike T1, the lightning resistance of the lightning protection wire exceeds the amount of discharge charge, so that the wire is not broken. For lightning strike T2, the discharge charge amount (50C) falls within the range of charge amounts corresponding to three and four wire breaks, so that the wire forming the lightning arrester breaks 3 to 4 wires. It is estimated that

  Furthermore, when it is estimated that the wire of the lightning wire has been broken by the lightning strike T2 as described above, the lightning wire is suspended between the tower to be verified, that is, the nearby steel tower with respect to the lightning strike T2, and both sides thereof. It is estimated that the wire broke between the steel towers.

  After estimating the number of breaks of the wire and the position on the lightning protection wire where the wire is broken, the result is output to a monitor connected to the computer (ST10). FIG. 9 is an example of the result display screen, and shows the number of the lightning breakage of the lightning conductor estimated in ST9 and the position on the lightning arresting line where the wire is broken. In the figure, a lightning strike indicated by “★” indicates “lightning strike T2”, and a nearby steel tower corresponding to this is a steel tower whose tower number is “241000”. Then, it can be seen that the steel towers over which the lightning wire is flanked on both sides of the steel tower 241000 are two steel towers with tower numbers “240000” and “242000”. In ST9, since it was estimated that the wire rod was broken between the nearby steel tower and the adjacent steel towers, the lightning conductors laid in the sections of the steel tower 240000 and the steel tower 241000, and the sections of the steel tower 241000 and the steel tower 242000 are indicated by thick lines. displayed.

  In addition, the equipment damage occurrence status, map information, area information, power transmission line information, lightning strike information, etc. may be displayed on the monitor.

  The equipment damage status indicates the estimated lightning strike energy (discharge charge amount) that is the cause of the wire breakage, the equipment damage occurrence status (for example, 3 to 4 wire breakage), and the section of the lightning conductor where the wire breaks.

  The map information indicates the coordinates of the range shown on the map in the figure.

  The area information indicates the transmission line name, the transmission voltage, and the number of lightning strikes that occurred in the same time zone (for example, 2 seconds).

  The power transmission line information indicates the number and coordinates of a nearby steel tower.

  The lightning strike information indicates the lightning strike date and time, the coordinates of the occurrence position, and the estimated lightning strike current value, which are the causes of the wire breakage.

  As mentioned above, although the Example of this invention was described, this invention is not limited to this. For example, in the embodiment, in order to estimate the number of breaks of the wire and the break position on the lightning conductor, as shown in ST3 and ST4 of the flowchart in FIG. It is determined whether or not it is within the range (for example, within 1 km), but it is also possible to determine whether or not the lightning conductor is passing within a predetermined range (for example, within 1 km) from the lightning occurrence position. Good. In this case, it is determined whether or not the distance between the lightning occurrence position and the straight line connecting the two nearest towers of the lightning occurrence position is within the predetermined distance, and if the determination result is “YES”, Based on the equipment information of the tower that is closest to the location where the lightning strikes between the two towers, find the relationship between the lightning discharge charge and the number of wire breakage of the lightning conductor, and compare this with the lightning discharge charge. Good. In this case as well, as in the embodiment, it is preferable that the relationship between the lightning discharge charge amount and the number of lightning breakage of the lightning conductor is obtained in advance and stored in a computer as a database.

A method for obtaining the distance between the lightning occurrence position and the lightning protection line will be described. First, the coordinates of the lightning occurrence position included in the LLS data are compared with the coordinates of the steel tower included in the facility information of each tower, and two nearest steel towers of the lightning occurrence position are extracted. From the extracted coordinates of the two steel towers, an equation of a straight line “L ₁ ” connecting the two steel towers is obtained. Next, a value obtained by multiplying the reciprocal of the slope of this straight line by “−1” is obtained, and this is used as a slope to obtain a formula “L ₂ ” of a straight line passing through the coordinates of the lightning strike position. Seeking expression and expression from both the linear intersection coordinates of "L _2" of the straight line "L _1", it may be obtained the distance between it and the coordinates of the lightning strike generating position.

  Further, the wire rod breakage of the lightning protection wire occurs most frequently in a power transmission line having a high power transmission voltage (for example, 500 kV), that is, a power transmission line suspended in a high height (for example, 80 m) among steel towers. In consideration of this point, in the “database indicating the relationship between the lightning discharge charge amount and the number of wire breaks” (FIG. 6) of the embodiment, the number of wire breakage is determined corresponding to the lightning discharge charge amount. For example, the number of wire breaks obtained in this database can be corrected by “the height of the steel tower” and “the altitude of the steel tower installation position”. For example, in the database shown in FIG. 6, when the number of wire breaks is estimated to be four, if the “steel tower height” or “the height of the tower installation position” is low, the role of correcting the number of wire breaks to two Can be fulfilled.

The flowchart of the lightning conductor damage estimation method of this invention. The figure which shows the generation | occurrence | production position of the lightning strike which generate | occur | produced around a certain lightning line. The figure which shows the positional relationship of the steel tower which flies over a lightning arrester, and a lightning strike location. The figure which shows the state which extracted the steel tower and lightning strike in which the distance between both is in a predetermined range. An example of a lightning discharge current waveform. An example of the database which shows the relationship between the electric discharge amount of a lightning strike, and a wire breakage number. The graph which shows the relationship between a lightning strike current, discharge continuation time, and a wire breakage number. The graph which shows the relationship between an electric charge amount and the number of wire breaks. An example of a result display screen showing the number of wires broken and the position on the lightning protection wire where the wire was broken.

Claims (4)

(A) determining a distance between a steel tower over which a lightning line for passing a lightning strike current to the ground and a lightning strike position;
(B) extracting the steel tower and the generated lightning strike with the distance within a predetermined range;
(C) obtaining a discharge charge amount from the extracted lightning discharge waveform of the lightning,
(D) determining the relationship between the amount of lightning discharge charge and the number of breaks of the wire forming the lightning protection line, based on the type and thickness of the lightning protection line over which the extracted steel tower is suspended;
(E) estimating the number of wire rod breakage of the lightning conductors in which the extracted steel towers are suspended by comparing the relationship with the discharge charge amount obtained in the step of obtaining the discharge charge amount. A method for estimating damage from lightning conductors.   The lightning line damage estimation method according to claim 1, wherein in the step (b), when there are a plurality of steel towers within the predetermined range for one lightning strike, a steel tower closest to the lightning strike is extracted. A method for estimating damage from lightning conductors.   In the lightning wire damage estimation method according to claim 1 or 2, when it is estimated that the wire rod of the lightning wire is broken by the collation of (e), the steel tower that is the object of the collation, A method of estimating damage to a lightning wire, comprising estimating that the wire has broken between a steel tower over which the lightning wire is suspended. 4. The lightning conductor damage estimation method according to claim 1, wherein the relationship of (d) is obtained in advance based on the type and thickness of the lightning conductor.

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