JP2001147279A - Lighting strike position orientation method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately orient a lighting strike position even with an error and the like in cumulative length of an optical fiber obtained from laid data. SOLUTION: A laser light from a laser source 2 placed in a power station is made incident in an outward side optical fiber 10a in OPGW and the light having passed the outward side optical fiber 10a, an optical fiber 4 for delay and a homeward side optical fiber 10b is received with a polarization variation analyzer 3. If the lighting strike is given on the way of power transmission line, the going light and returning light passing the o9ptical fibers 10a and 10b respectively receive polarized wave variation. From the time difference of twice-polarized wave variation, the lighting strike position on the optical fiber is roughly defined. The intervals of variation points of inclination of time variation of the polarized wave variation angle waveform in the vicinity of the lighting strike position is analyzed and the pattern of fiber length between pylons is obtained to correlate with the pattern in the row. From the relation between the two patterns, the lighting strike position between pylons is defined.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power line, an OPGW,
The present invention relates to a method for locating a lightning strike position when a lightning strike occurs on a transmission line composed of:

[0002]

2. Description of the Related Art A method using polarization fluctuation of light in an OPGW to locate a lightning strike position on a transmission line composed of a plurality of towers, power lines, and an OPGW is known (for example, Japanese Patent No. 2818674). No.). OPGW (Optical Gr
Sound wire (optical composite ground wire) is a type of overhead ground wire that spans the tops of power transmission towers and also serves as a lightning arrester.
As shown in FIG. 5, the outer side of the structure is a spirally twisted aluminum-coated steel wire, and the center is an aluminum tube containing an optical fiber. The structure shown in FIG. 5 is very important for the operation of lightning location, and a part of a very large lightning current at the time of lightning strike flows like a coil surrounding an optical fiber in the center. Then, as shown in FIG.
A magnetic field is generated inside the GW, and a light wave traveling through the OPGW undergoes a large polarization fluctuation due to the influence of the magnetic field. It should be noted that also in a wound optical composite ground wire in which an optical fiber is wound around the outer circumference of the ground wire, a magnetic field is generated by the lightning current in the same manner as described above, and the same phenomenon occurs.

Accordingly, as shown in FIG. 6, a laser light source 2 is provided on one side of an OPGW 1 of a transmission line to be monitored for lightning strike, a laser beam is incident on the OPGW 1 from one side, and the light returned and returned on the other side is polarized. If the polarization analysis is performed by the fluctuation analysis unit 3, the lightning strike position can be located. That is, in FIG. 6, when there is a lightning strike on the OPGW,
Because the above-mentioned effect causes the light going near the lightning strike position and the folded light to undergo polarization fluctuations, respectively, as shown in FIG.
There are two peaks in the time change of the polarization moving speed, which is the observation waveform of the polarization fluctuation. The lightning strike position can be located from the time difference between the two polarization fluctuations.

[0004]

According to the above method, O
Although the position of the lightning strike on the optical fiber of the PGW can be specified, it is not known which position it corresponds on the actual transmission line. Because the polarization fluctuation due to the lightning strike occurs in the light passing through the optical fiber in the OPGW, the analysis result is the position on the optical fiber. Therefore, in order to know where the lightning strike actually occurred, it is necessary to relate the length of the transmission line to the actual length of the optical fiber laid. Where OP
Explaining the laying state of the GW, there is one connection point of the OPGW in several towers, and at this point, the OPGW is pulled down to the lower part of the tower as shown in FIG. 8, and the optical fiber in the OPGW is fused. Further, there is a slack between the steel towers as shown in the figure, and in addition, as shown in FIG. 9, there is a twist of an optical fiber unit in which a plurality of optical fibers are assembled.

[0005] In consideration of these, from the installation data such as the tower height, span length, twisting rate, sag, and elevation of the installation position shown in FIG. Calculate the length. In this way, by linking the cumulative sum of the actual lengths of the optical fibers and the tower number, it becomes possible to specify the location near the tower where the lightning strike occurred. However, since it is difficult to accurately obtain the data of the sag and the reduction length, an error occurs in the relationship between a certain tower and the actual accumulated optical fiber length to the tower,
The error increases as the distance from the tower increases. Furthermore, the time width of the lightning current pulse may be as long as several tens of towers in terms of distance, and there is a limit to improving the positioning accuracy. As described above, in the conventional method, it was difficult to accurately locate the lightning strike position due to an error in the accumulated actual length of the optical fiber. The present invention has been made in order to solve the above-described problems of the related art, and even if there is an error in the accumulated actual length of the optical fiber obtained from the laying data, it is possible to accurately locate the lightning strike position. It is an object of the present invention to provide a method for locating a lightning strike that can be performed.

[0006]

FIG. 2 (a) shows a time change of the polarization moving angle at the time of a lightning strike, and is a kind of magneto-optical effect like the time change of the polarization moving speed shown in FIG. Due to a certain Faraday effect, the plane of polarization rotates as shown in FIG. In the present invention, the lightning strike position is located using the time change of the polarization movement angle shown in FIG. Since the pulse width of the lightning current is several tens of μs, the change of the polarization fluctuation has the same time width. This time width is equivalent to several pylons in terms of distance. When the waveform shown in FIG. 2A is enlarged, FIG.
As shown in (b), there was a slight change in the inclination, and it was found that the interval between the change points was in good agreement with the fiber length between the towers. The exact cause of this phenomenon is unknown, but O
Since the PGW is grounded for each of the towers, it is considered that the minus part of the lightning current flows to the surface of the ground and the amount of current changes.

The present invention uses this phenomenon to locate a lightning strike position as follows. (1) First, when a lightning strike waveform is obtained, an approximate lightning strike position is specified by the above-described conventional method. Next, for the dozens of towers near the lightning strike position obtained by the above-mentioned conventional method, the change point interval of the slope with respect to the time change of the polarization plane rotation angle described in FIG. Obtain the fiber length between towers. Then, a point where the pattern of the fiber length between towers and the pattern of the fiber length between towers calculated from the laying data substantially match is searched. On the other hand, the lightning strike position corresponds to the time point F at which the change in the polarization movement angle indicated by the arrow in FIG. 2A is the steepest. If this point F can be associated with the position between the towers, the lightning strike position is changed. Can be oriented. Therefore, the position between the towers corresponding to the point F is obtained from the correspondence between the arrangement of the fiber lengths between the towers obtained as described above and the pattern of the arrangement of the fiber lengths between the towers calculated from the laying data. (2) An optical signal is input from one end of the optical fiber, and the time change of the rotation angle of the polarization plane appearing at the other end of the optical fiber during a lightning strike is observed. Then, based on the above-described pattern of the change point interval of the inclination with respect to the time change of the polarization plane rotation angle, the inter-pylon fiber length near the time point F at which the change of the polarization moving angle becomes the steepest shown in FIG. obtain. Then, a point where the pattern of the fiber length between the towers obtained from the pattern of the change point intervals of the inclination with respect to the time change of the rotation angle of the polarization plane and the pattern of the fiber length between the towers calculated from the laying data substantially match is searched. Next, the position between the towers corresponding to the point F is obtained from the correspondence between the arrangement of the fiber lengths between the towers obtained as described above and the pattern of the arrangement of the fiber lengths between the towers calculated from the laying data. The above (1) and (2)
In this way, it is possible to specify the location of the lightning tower where the lightning strike occurred, and it is possible to accurately locate the lightning strike position. The optical fiber is desirably housed in a unit (for example, the above-mentioned OPGW). In particular, when an optical fiber is folded back at the end of the transmission line, and the lightning strike position is roughly located based on the time difference between two polarization fluctuations,
Optical fiber in the same unit (same O for OPGW)
(PGW) can facilitate installation.

[0008]

FIG. 1 is a diagram showing a configuration example of a lightning strike position locating system according to a first embodiment of the present invention. In the figure, reference numeral 10 denotes a transmission line tower, and an OPGW 1 is installed above the transmission line tower 10 in parallel with the transmission line. O
The PGW 1 accommodates a continuous optical fiber 10 that is turned back and forth at the end of the transmission line, and the turned-back portion is connected to a delay optical fiber 4 for increasing the propagation distance. Further, a laser light source 2 and a polarization fluctuation analysis unit 3 are provided on the power plant side, and the laser light emitted from the laser light source 2 is transmitted to the optical fiber 10
a. The laser light enters the delay optical fiber 4 installed on the substation side via the outward optical fiber 10a of the OPGW 1, is delayed by the delay optical fiber 4, and
It is turned back to the power station side via the return optical fiber 10b of the PGW 1, and enters the polarization fluctuation analyzer of the polarization fluctuation analyzer 3 provided on the power station side.

In the above configuration, if a lightning strike occurs in the middle of the transmission line, as described above, the light going back and forth through the forward optical fiber 10a and the return optical fiber 10b near the lightning point is deflected. Subject to wave fluctuations. The polarization fluctuation analysis unit 3 analyzes the above-mentioned polarization fluctuation, and transmits the analysis result to the data collection / analysis unit 5 via the telephone line 6. The data collection / analysis unit 5 locates a lightning strike position based on the analysis result. When a lightning strike occurs on the transmission line, two peaks occur in the time variation of the polarization fluctuation moving speed observed by the polarization fluctuation analysis unit 3 as shown in FIG. As described above, the lightning strike position on the optical fiber of the OPGW can be located from the time difference between the two polarization fluctuations. As described above, since the time width of the polarization fluctuation waveform is wide, in the case of a lightning strike near a substation, two waveforms overlap, and it is impossible to locate the lightning strike position. In order to prevent this, the optical fiber 4 for delay is installed in the substation as described above.

[0010] According to the above method, the lightning strike position on the optical fiber can be located as described above. However, in the above-described conventional method, as described above, the fiber length is obtained as the sum of the span lengths calculated from the tower data for each tower, and it is difficult to accurately obtain the data of the sag and the lowered length. For this reason, an error occurs in the relationship between a certain tower and the actual optical fiber length to the tower, and the deviation increases as the distance from the tower increases. Furthermore, the pulse of the lightning current may be as wide as more than a dozen towers in terms of distance, and the error is large.

Therefore, in the data collection / analysis section 5, 2
For dozens of towers near the lightning strike position obtained from the time difference of the degree of polarization change, the interval of the change point of the slope of the time change of the polarization change angular waveform is analyzed, and the lightning strike position is located as follows. FIG. 3 is a view for explaining a method for locating a lightning strike based on a change over time in the angle of polarization fluctuation, wherein A in FIG.
Similarly to FIG. 7, the slope of the polarization fluctuation angle waveform with respect to time change is shown. As shown in A of the figure, the polarization fluctuation angle waveform has a slight change in inclination, and the interval between the change points matches the fiber length between the towers well as described above. In the case of this example, the pattern of the span length obtained from the interval of the change point is
As shown in the figure, 102m, 87m, 108m, ..., 1
34m and 159m.

On the other hand, the lightning strike position is
9 is located between the tower 9 and the tower, and a pattern in which the length of the fiber length between the towers calculated from the laying data of the tower near the lightning strike position matches the above pattern is searched. 100m, 90m, 110m, ..., 130m, 160m between the tower 64 and the tower 72
Assume that Here, assuming that the position corresponding to the point F in FIG. 2A is the point f in FIG. 3, this point is a position where the fiber length between the towers is 123 m, and this point is calculated from the laying data. Corresponding to the pattern of the fiber length between the towers corresponds to between the tower 68 and the tower 67 (point f in FIG. 3 is point F (lightning strike position) in FIG. 2A).
, And the point f is not always the point having the steepest slope in FIG. 3). Therefore, the lightning strike position is determined to be between the tower 68 and the tower 67.

[0013] According to the above method, since the empty core wire housed in the existing OPGW is used as a detection medium and a transmission medium, additional equipment to the transmission line tower as in the conventional fault section location system is not necessarily provided. It is not necessary, and the position of the lightning strike can be accurately located. In particular, even if there is an error in the relationship between the tower and the accumulated actual optical fiber length between the tower, it is possible to correct this and accurately locate the lightning strike position. Furthermore, in this method, by continuing to correct the calculated fiber length profile at each lightning strike, a more accurate fiber length profile between the towers of the entire transmission line is completed, contributing to improved positioning accuracy during lightning strikes. can do. In the above embodiment, two round trips of the optical fiber were used for lightning monitoring for a total of 2 strokes.
Although the book is occupied, it is possible to share an optical fiber with an optical communication line by using the wavelength multiplexing technology.

FIG. 4 is a view showing a second embodiment of the present invention. In this embodiment, a lightning strike position is located by one optical fiber. In FIG. 4, reference numeral 11 denotes a transmission line tower, and an OPGW 1 is installed above the transmission line tower 11 in parallel with the transmission line. Further, a laser light source 2 is provided on the substation side, and a polarization fluctuation analysis unit 3 is provided on the power plant side. Laser light emitted from the laser light source 2 is incident on the above-mentioned OPGW1 free core wire. . The laser light is sent to the power station via the optical fiber 10 in the OPGW 1 and enters the polarization fluctuation analysis unit 3 provided on the power station.

In the above configuration, if there is a lightning strike in the middle of the transmission line, the light emitted from the laser light source 2 and transmitted through the optical fiber 10 in the OPGW 1 undergoes polarization fluctuation.
The polarization fluctuation analysis unit 3 analyzes the above-mentioned polarization fluctuation, and transmits the analysis result to the data collection / analysis unit 5 via the telephone line 6. The data collection / analysis unit 5 locates the lightning strike position based on the analysis result as follows. When lightning strikes the transmission line, the polarization plane rotation angle of the light received by the polarization fluctuation analysis unit 3 changes with time as described above. From the time change of the polarization plane rotation angle, a point F which is a lightning strike position indicated by an arrow in FIG. 2A can be obtained. Further, the time change of the polarization plane rotation angle has a slight change in inclination as described with reference to FIG. 3, and the interval between the change points is in good agreement with the fiber length between the towers as described above. Therefore, as described with reference to FIG. 3, from the correspondence between the arrangement of the fiber lengths between the towers obtained as described above and the pattern of the arrangement of the fiber lengths between the towers calculated from the laying data, the tower corresponding to the point F is determined. Find the intermediate position. In the case of FIG. 3, the lightning strike position is specified to be between the tower 68 and the tower 67, as in the first embodiment. The optical fiber used in the present invention is not limited to the form housed in the OPGW as described above, and is arranged along the transmission line on which the lightning position is to be located. Is enough. When the optical fiber is folded back at the end of the transmission line and the lightning position is roughly determined from the time difference between the two polarization fluctuations observed at the lightning point, the optical fiber must be placed in the same unit (OP
It is preferable to accommodate the GW in the same OPGW.

[0016]

As described above, in the present invention, the interval between the change points of the inclination with respect to the time change of the polarization plane rotation angle is obtained, and the inter-tower fiber length is obtained from the obtained change point interval. The lightning strike position was located by searching for a point where the arrangement of the length and the pattern of the fiber length between the towers calculated from the laying data almost matched.Therefore, there was an error in the accumulated actual optical fiber length obtained from the laying data. Even if there is, etc., the lightning strike position can be accurately located.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a configuration example of a lightning strike position locating system according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a time change of a polarization movement angle at the time of lightning strike.

FIG. 3 is a diagram illustrating a method for locating a lightning strike based on a time change of a polarization fluctuation angle.

FIG. 4 is a diagram illustrating a configuration example of a lightning strike position locating system according to a second embodiment of the present invention.

FIG. 5 is a diagram illustrating a lightning current flowing on an OPGW surface and a generated magnetic field.

FIG. 6 is a diagram illustrating a conventional method.

FIG. 7 is a diagram showing a polarization fluctuation waveform.

FIG. 8 is a diagram illustrating a laying state of an OPGW in a transmission line.

FIG. 9 is a diagram illustrating twisting of an optical fiber in an OPGW.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 OPGW 2 Laser light source 3 Polarization fluctuation analysis part 4 Delay optical fiber 5 Data collection and analysis part 6 Telephone line 10 Optical fiber 11 Transmission line tower

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Kunio Odaka 2-6-1 Marunouchi, Chiyoda-ku, Tokyo Inside Furukawa Electric Co., Ltd. (72) Inventor Hiroyuki Sumitani 4-33 Komachi, Naka-ku, Hiroshima-shi, Hiroshima Prefecture Chugoku Electric Power Co., Inc. (72) Inventor ▲ Kage ▼ Hiroshi Yama 4-3-33 Komachi, Naka-ku, Hiroshima-shi, Hiroshima Chugoku Electric Power Co., Inc. F-term (reference) 2G033 AA01 AB01 AC06 AD00 AG13 AG14

Claims (4)

[Claims] 1. A continuous optical fiber that is folded back at an end of a transmission line and is reciprocated at an upper portion of a tower of the transmission line in parallel with a transmission line, and an optical signal is input from one end of the optical fiber. A lightning strike location method for locating a lightning strike by observing polarization fluctuations received through the optical fiber during a lightning strike, wherein the lightning strike position is roughly determined by the time difference between the two observed polarization fluctuations. Orienting, associating the pattern of the change point interval of the inclination with respect to the time change of the polarization plane rotation angle in the vicinity of the electric shock position with the span distance pattern of the steel tower, A lightning strike position between towers corresponding to a lightning strike position on an optical fiber. 2. The lightning strike position locating method according to claim 1, wherein a continuous optical fiber that is turned back and forth at the end of the transmission line is housed in the same unit. 3. An optical fiber is provided above a steel tower of a transmission line in parallel with a transmission line, and an optical signal is input from one end of the optical fiber, and a polarization appears at the other end of the optical fiber when lightning strikes. A method of locating a lightning strike position by observing a variation, wherein a pattern of a change point interval of a slope with respect to a time change of a polarization plane rotation angle and a distance pattern of a steel tower are associated with each other. A method for locating a lightning strike between towers corresponding to a lightning strike position on an optical fiber obtained by a time change of a polarization plane rotation angle based on the above method. 4. The lightning strike location method according to claim 3, wherein the optical fiber is housed in a unit.