JP2022161060A - System and method for measuring amount of snow and ice accretion on overhead transmission line - Google Patents

Abstract

To provide a system and a method for measuring an amount of snow and ice accretion on an overhead transmission line which can easily and quickly measure the amount of snow and ice accretion on the overhead transmission line.SOLUTION: A system 1 for measuring an amount of snow and ice accretion on an overhead transmission line which measures an amount of snow and ice accretion on an overhead transmission line 5 comprises: a flight body 2 which is mounted with an imaging apparatus 20; and a measuring apparatus 3 which measures the amount of snow and ice accretion on the overhead transmission line 5. The flight body 2 photographs the overhead transmission line 5 with the imaging apparatus 20 while flying and transmits data D of photographed images to the measuring apparatus 3. The measuring apparatus 3 calculates a sag d of the overhead transmission line 5 based on the data D of the transmitted images and measures the amount of snow and ice accretion on the overhead transmission line 5 based on the calculated sag d of the overhead transmission line 5.SELECTED DRAWING: Figure 1

Description

The present invention relates to a system for measuring the amount of icing and snow on an overhead transmission line and a method for measuring the amount of icing and snow on an overhead transmission line.

If snow or ice adheres to an overhead power transmission line (hereinafter, simply referred to as an electric wire), phenomena such as galloping and sleet jumping may occur, and adjacent electric wires may come into contact with each other, leading to a short-circuit accident.
For this reason, conventionally, the amount of ice and snow accreted on electric wires is visually observed and the amount of ice and snow accreted on electric wires is measured by a robot (see Non-Patent Document 1).

J-Power Systems Co., Ltd., “Overhead Power Transmission Line Business Division”, [Searched on March 29, 2021], Internet <URL: https://www.jpowers.co.jp/product/pdf/kakuC .pdf＞ Kansai Electric Power Transmission and Distribution Co., Ltd., “Protecting transmission lines from heavy snowfall. Removing snow from transmission towers”, [searched on March 29, 2021], Internet <URL: https://www.kansai-td.co. jp/supply/mission/aerial-01.html＞

However, in order to measure the amount of ice and snow on electric wires, even if it is done by a robot, it is necessary to go to the site in a snowy mountain or perform the work at the site (see, for example, Non-Patent Document 2, etc.). It was a tough job for a person.
In addition, it is often performed by a relatively large number of people over several days, which is costly.
Furthermore, there is a problem that the measurement cannot be performed quickly even in an emergency such as when a short-circuit accident occurs.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems. An object of the present invention is to provide a method for measuring the amount of ice and snow accretion to electric wires.

In order to solve the above problem, the invention according to claim 1,
A system for measuring the amount of icing and snow on an overhead transmission line, comprising:
an aircraft carrying an imaging device;
a measuring device that measures the amount of ice and snow accretion on the overhead power transmission line;
with
The flying object captures an image of the overhead power line with the imaging device while flying, and transmits data of the captured image to the measurement device,
The measuring device calculates the sag of the overhead power transmission line based on the transmitted data of the image, and calculates the amount of ice and snow on the overhead power transmission line based on the calculated sag of the overhead power transmission line. It is characterized by measuring.

The invention according to claim 2 is the system for measuring the amount of ice and snow on an overhead power transmission line according to claim 1, wherein the flying object is one of two steel towers to which the overhead power transmission line is stretched. The overhead transmission line is photographed from a predetermined height position on the side of the transmission tower so as to include the bottom of the sag of the other transmission tower and the overhead transmission line.

According to a third aspect of the invention, in the system for measuring the amount of ice and snow on an overhead power transmission line according to the first or second aspect, the temperature and the theoretical value of sag are associated with each other. , the sag of the overhead power transmission line calculated based on the data of the image, and the sag of the overhead power transmission line calculated based on the data of the image by calculating the sag theoretical value at the air temperature measured near the overhead power transmission line by the flying object from the sag table; The method is characterized in that the amount of ice and snow accretion to the overhead transmission line is calculated and measured based on the theoretical sag value calculated from the table.

The invention according to claim 4 is the system for measuring icing and snow accretion on an overhead power transmission line according to claim 3, further comprising: A wind pressure load is calculated, and based on the calculated wind pressure load, the amount of icing and snow on the overhead power transmission line is calculated and measured.

The invention according to claim 5 is the system for measuring icing and snow accretion on overhead power transmission lines according to any one of claims 1 to 4, wherein the measurement device comprises It is characterized by measuring the vertical thickness and horizontal thickness of the accreted snow on the overhead transmission line based on the images taken from the direction and the vertical direction.

The invention according to claim 6 is the system for measuring icing and snow accretion on an overhead power transmission line according to any one of claims 1 to 5, wherein the measurement device measures the image of the overhead transmission line. calculating the volume of accreted snow and ice on the overhead transmission line based on the data, and calculating the specific gravity of the accreted snow and ice on the basis of the calculated volume and the measured amount of icing and snow on the overhead transmission line; Characterized by

The invention according to claim 7,
A method for measuring the amount of icing and snowing on an overhead transmission line, comprising:
a photographing step of photographing the overhead power transmission line with the photographing device while an aircraft equipped with the photographing device flies;
a transmission step of transmitting the data of the captured image to the measuring device;
a slackness calculation step in which the measurement device calculates the sagness of the overhead power transmission line based on the data of the transmitted image;
an icing/snowing amount measuring step of measuring the amount of icing/snowing on the overhead transmission line based on the calculated sag of the overhead transmission line;
characterized by comprising

Advantageous Effects of Invention According to the present invention, it is possible to easily and quickly measure the amount of ice and snow on an overhead power transmission line.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an image diagram showing a flying object, a measuring device, etc. in a system for measuring the amount of ice and snow on an overhead power transmission line and a method for measuring the amount of ice and snow on an overhead power transmission line according to the present embodiment; 1 is a block diagram showing the configuration of an aircraft; FIG. It is a block diagram showing the structure of a measuring device. 4 is a flow chart showing each step of a method for measuring the amount of ice and snow accreted to an overhead transmission line; FIG. 2 is a diagram for explaining the vertical and horizontal thicknesses of an overhead power transmission line and photographing the overhead power transmission line from the lateral direction and above; FIG. 4 is a diagram showing an example of an image of an overhead power transmission line photographed so as to include the other steel tower and the sag bottom of the overhead power transmission line. It is a figure explaining the method of calculation of the sag of an overhead power transmission line by a different length method. FIG. 4 is a diagram showing the relationship of loads applied to overhead power transmission lines when the wind is blowing; FIG. 4 is a diagram showing the relationship of loads applied to overhead power transmission lines when no wind is blowing; FIG. 10 is a diagram showing an example of an image of an overhead power transmission line taken in a windy state so as to include the other tower and the sag bottom of the overhead power transmission line.

Hereinafter, a system for measuring the amount of ice and snow on an overhead power transmission line and a method for measuring the amount of ice and snow on an overhead power transmission line according to the present invention will be described with reference to the drawings.
However, although various technically preferable limitations are attached to the embodiments described below to carry out the present invention, the scope of the present invention is not limited to the following embodiments and illustrated examples. do not have. Further, hereinafter, the system for measuring the amount of icing and snow on overhead transmission lines and the method for measuring the amount of icing and snow on overhead transmission lines may be simply referred to as the system and method for measuring the amount of icing and snow.

FIG. 1 is a diagram showing the configuration of a system for measuring the amount of ice and snow accretion onto an overhead transmission line according to this embodiment. In this embodiment, a system 1 for measuring the amount of ice and snow accretion to an overhead transmission line includes an aircraft 2 and a measuring device 3 .
In the ice and snow amount measuring system 1 and the ice and snow amount measuring method according to the present embodiment, the electric wire (overhead transmission line) 5 is photographed by the photographing device 20 mounted on the aircraft 2, and data of the photographed image (hereinafter referred to as , referred to as image data D), the measurement device 3 calculates the degree of sag d of the wire 5, and the amount of icing and snow I on the wire 5 (such as the weight of icing and snow Wi) is calculated based on the calculated sag d of the wire 5. ).

In FIG. 1 and the like, 6 denotes a steel tower, 7 denotes a cross arm, and insulators, overhead ground wires, etc. are omitted. In addition, although only three upper and lower electric wires 5 are shown in FIG. Also, the relative sizes of the steel tower 6 and the flying object 2 do not reflect reality.
In addition, although the measuring device 3 is shown at a position between two steel towers 6 in FIG. , does not mean that the measuring device 3 is arranged at a position between the two steel towers 6.

FIG. 2 is a block diagram showing the configuration of the aircraft. Although the flying object 2 is shown as a drone in FIGS. 1 and 2, it may be, for example, a helicopter type.
As shown in FIG. 2, the aircraft 2 is configured to be equipped with a control unit 21, a memory 22, a drive control unit 23, a distance measurement unit 24, a wireless communication unit 25, sensors 26, etc., in addition to the imaging device 20. It is

Further, although illustration is omitted, in the present embodiment, the flying object 2 receives satellite signals from artificial satellites such as GPS (Global Positioning System) satellites and quasi-zenith satellites to determine the position of the flying object 2 (latitude, longitude or latitude, longitude, and altitude).
In this embodiment, it is assumed that the flying object 2 is operated by an operator or the like, but the flying object 2 may fly autonomously. In this case, the flying object 2 is configured to store necessary information such as map information including the positions of the steel tower 6 and the electric wires 5 and power transmission line information in a memory 22 to be described later.

The image capturing device 20 may capture either a still image or a moving image, and the image may be monochrome or color.
1 and 2 show a case in which two photographing devices 20 are mounted on the aircraft 2, the photographing device 20 mounted downward and the photographing device 20 mounted sideways. It is also possible to configure such that the photographing direction of one photographing device 20 can be freely changed.

Further, in this embodiment, the scale 20a is arranged in the photographing direction of the photographing device 20, so that when photographing is performed by the photographing device 20, the scale 20a appears in the image.
It is also possible to configure the scale 20a so that it can be moved to a position outside the imaging range of the imaging device 20 when the scale 20a is not used.

The control unit 21 is composed of a computer including a CPU (Central Processing Unit) and the like, and performs overall control of the aircraft 2 including the imaging device 20 .
Note that the control unit 21 may be composed of a dedicated device.
The memory 22 is composed of a ROM (Read Only Memory), a RAM (Random Access Memory), etc., and stores various control programs 22a and the like.

Under the control of the control unit 21, the drive control unit 23 controls a driving device such as a motor (not shown) for rotating the rotor blades 23a of the flying object 2 to cause the flying object 2 to fly appropriately.
The distance measurement unit 24 is composed of a distance measurement sensor or the like having a laser device or the like, and is capable of measuring the distance between the photographing device 20 and an object (electric wire 5 or the like).

Also, the flying object 2 is designed to perform wireless communication with the measuring device 3, and has a wireless communication unit 25 such as a wireless communication module for that purpose.
Further, sensors 26 such as a wind speed sensor, a temperature sensor, and a pyranometer are attached to the flying object 2 .

Although not shown, the aircraft 2 is also equipped with necessary devices such as a battery and an engine.
Further, the wind speed V can be measured by the wind speed sensor as described above. It is also possible to configure the control unit 21 to determine the wind speed V of the outside air from the control value of .

FIG. 3 is a block diagram showing the configuration of the measuring device. The measurement device 3 is a device for measuring the amount of ice and snow accretion to the electric wire (overhead transmission line) 5, as described above.
As shown in FIG. 3, the measuring device 3 includes a control section 31, a wireless communication section 32, a memory 33, a display screen 34, and the like. It should be noted that, in addition to this, it may be configured so as to be equipped with sensors or connectable to a communication network as necessary.

The control unit 31 may be configured by a computer, or may be configured by a dedicated control device or the like. The control unit 31 performs overall control of the measuring device 3 according to a control program 33a, which will be described later.
Moreover, the measuring device 3 is adapted to perform wireless communication with the aircraft 2, and has a wireless communication unit 32 such as a wireless communication module for that purpose. The wireless communication unit 32 stores the image data D in the memory 33 when data of an image captured by the imaging device 20 (hereinafter referred to as image data D) is transmitted from the aircraft 2 . The control unit 31 performs simple image processing on the transmitted image data D to generate an image and displays it on a display screen 34 such as a liquid crystal display.

The memory 33 stores various control programs 33a. In addition, the memory 33 stores power transmission line information 33b including the numbers of the towers 6, structural drawings, information on the electric wires 5 stretched between the towers 6, and the like. The type of the electric wire 5 also includes information such as the thickness of the electric wire 5 .
Further, the memory 33 stores the image data D received by the wireless communication section 32 in the storage area 33c.

In addition, in this embodiment, the power transmission line information 33b includes a slackness table, which will be described later. Also, map information and the like may be stored in the memory 33 .
Then, the control unit 31 displays the map on the display screen 34, and also displays the figure of the flying object 2 on the displayed map to show where the flying object 2 is flying on the map. It is also possible to configure

[Photographing of electric wires, processing in measuring equipment, and method for measuring the amount of ice and snow accretion on overhead power transmission lines]
Next, photographing of the wire 5 and the like by the aircraft 2 and processing in the measurement device 3 in the icing/snow accretion measurement system 1 according to the present embodiment will be described.
Also, a method for measuring the amount of ice and snow on the overhead power transmission line for measuring the amount of ice and snow on the electric wire 5 will be described.

Here, the slackness table will be explained.
There is a sag design that designs in advance at what sag d the wire 5 is to be laid when the electric wire 5 is wired to the steel tower 6 in a section of the transmission line (that is, between the steel towers 6). done. For sag design, see, for example, Hideyo Takeshita, "Sag of Overhead Transmission Lines - Theory of Sag and Tension and Their Calculations (Enlarged and Revised Edition)", Denryokusha, January 1957, p. 26-56.

Then, at that time, for example, the sag d is calculated in a temperature range of −10° C. to 40° C., and the sag d of the electric wire 5 in a state of no wind, no ice and snow (described later) is calculated at each temperature in increments of 1° C., for example. The slackness table is a correspondence between the sag theoretical values di).
A sag table is created in advance for each section of the transmission line. As described above, the measuring device 3 has the sag table for each section of each transmission line in the memory 33 . It should be noted that it is also possible to configure the measuring device 3 to read the required sag table from a database or the like in which the sag table for each section of each transmission line is stored.

When the electric wire 5 is laid on the steel tower 6, the sag d corresponding to the air temperature at that time is calculated from the sag table, and the electric wire 5 is laid so as to achieve the sag d.
Further, when operation is started and electric current flows through the electric wire 5, the temperature of the electric wire 5 rises and the length of the electric wire 5 increases, so the slackness d increases.

In the present embodiment, the slackness d of the electric wire 5 (that is, the current slackness d of the electric wire 5) is calculated based on the image data D by the measuring device 3 as described above (and as described below). However, in order to distinguish from this sag d, the sag calculated by the sag design as described above is hereinafter referred to as the sag theoretical value di.

The method for measuring the amount of ice and snow on overhead power transmission lines includes the steps shown in FIG.
In the present embodiment, the method for measuring the amount of icing and snowing on the overhead power transmission line includes a photographing step (step S1), a transmission step (step S2), a thickness measuring step of icing and snow (step S3), and a sag calculation. It includes a step (step S4) and an icing/snow amount measuring step (step S5).

[Photography process]
In the photographing step (step S1), the flying object 2 equipped with the photographing device 20 photographs the electric wire 5 with the photographing device 20 while flying.
In this step, the worker or the like flies the flying object 2 from the base of the work site (for example, the place where the flying object 2 and the measuring device 3 are carried) to the vicinity of the electric wire 5 to be measured.

In the present embodiment, in the photographing step, the electric wire 5 is photographed by the photographing device 20 for at least the following two points from the viewpoint of measuring the amount of ice and snow on the electric wire 5 .
(A) As a first aspect of measuring the amount of icing and snowing on the electric wire 5, the thickness of the ice or snow I (icing and snowing) adhering to the electric wire 5 is measured and the state of the adhering ice or snow I is observed. For this purpose, the flying object 2 is moved to a position around the electric wire 5 like the flying object 2A in FIG.
(B) As a second aspect of measuring the amount of icing and snowing on the electric wire 5, the slackness d of the electric wire 5 required to measure the weight of icing and snowing Wi on the electric wire 5 (i.e., the current sag of the electric wire 5 In order to calculate d), the flying object 2 is moved to the vicinity of one steel tower 61 like the flying object 2B in FIG. 1, and the electric wire 5 and the other steel tower 62 are photographed.

First, in the photographing of (A), as shown in FIG. While hovering on the side, the electric wire 5 is photographed from the lateral direction by the photographing device 20. - 特許庁
Then, the flying object 2 stores the distance La between the photographing device 20 and the electric wire 5 measured by the distance measuring unit 24 at that time in association with the photographed image.

In addition, as shown in FIG. 5, the operator or the like moves the flying object 2 above the electric wire 5 and makes it hover in order to measure the horizontal thickness b of the ice or snow I adhering to the electric wire 5. while directing the photographing device 20 downward to photograph the electric wire 5 from above. The electric wire 5 may be photographed from below with the photographing device 20 directed upward.
Then, the flying object 2 stores the distance Lb between the photographing device 20 and the electric wire 5 measured by the distance measuring unit 24 at that time in association with the photographed image.

In the photographing of (A), the scale 20a is arranged in the photographing direction of the photographing device 20 so that the scale 20a (see FIG. 2) appears in the photographed image.
In addition, the worker or the like can determine the state of the ice or snow I adhering to the electric wire 5, that is, whether the electric wire 5 is frozen, whether the electric wire 5 is covered with snow, or whether the attached ice or snow I is wet or dry. , the cross section of the ice or snow I adhering to the electric wire 5 is elliptical, the windward side is thick, and the adhering state of the electric wire 5 is spirally attached in the longitudinal direction. .

Then, the operator or the like moves the aircraft 2 along the electric wire 5 and takes the above (A) images at a plurality of locations on the electric wire 5 (for example, at predetermined distances).
Also, the operator or the like takes the image of (A) above for each electric wire 5 .

On the other hand, the operator or the like performs the photographing of the above (B) before or after the photographing of (A).
In the photographing of (B), the operator or the like moves the flying object 2 to one of the two steel towers 6 on which the electric wires 5 are stretched, as shown in FIG. Then, while watching the moving image transmitted from the flying object 2, it is positioned at a predetermined height of one of the steel towers 61, for example, at the position of the lowermost metal arm portion 71E (see FIG. 1) of the metal arm portions 7. Move the aircraft 2.

Then, the operator or the like makes the flying object 2 hover at that position (the position of the arm portion 71E) and does not raise or lower the altitude from that position (it is possible to move the flying object in the horizontal direction). , as shown in FIG. 6, the electric wire 5 is photographed so that the other steel tower 62 and the sag bottom 5a of the electric wire 5 are included.

When photographing the other steel tower 62 and the sag bottom 5a of the electric wire 5 as described above, as shown in FIG. A plurality of cross arm portions 72A to 72E of the steel tower 62 (the cross arm portions 72C to 72E are shown in FIG. 6), and other portions of the steel tower 62 whose actual lengths, intervals, etc. can be easily understood from the structural drawing of the steel tower 62. If it is photographed, it becomes possible to easily perform calculation processing of the degree of slackness d of the electric wire 5, which will be described later.

[Transmission process]
Then, the control unit 21 of the flying object 2 transmits the image data D and the like captured by the imaging device 20 to the measurement device 3 (transmission step (step S2)).
In this case, the image data D and the like obtained by photographing with the photographing device 20 are temporarily stored in the memory 22 of the flying object 2, and after the photographing of the target electric wire 5 is completed, they are collectively transmitted to the measuring device 3. Alternatively, the image data D and the like may be transmitted to the measurement device 3 each time the imaging device 20 captures an image.

[Thickness measurement process of icing and snow]
When the image data D and the like obtained by the photographing of (A) are transmitted from the flying object 2 as described above, the measurement device 3 performs the first measurement for measuring the amount of ice and snow accretion on the electric wire 5. , the vertical thickness a and horizontal thickness b (see FIG. 5) of the ice and snow I (icing snow) adhering to the electric wire 5 are calculated and measured based on the transmitted image data D etc. (step of measuring thickness of accreted snow (step S3)).
In this case, as described above, the scale 20a (see FIG. 2) is captured in the captured image of the ice or snow I adhering to the electric wire 5. FIG. Also, the distance between the imaging device 20 and the scale 20a is known in advance.

Then, from the relationship between the distance between the photographing device 20 and the scale 20a and the number of pixels corresponding to one unit (for example, 1 cm) of the scale 20a on the image, the distance La between the photographing device 20 and the electric wire 5 and the photographing in the image Based on the number of pixels of the snow accretion I obtained in the vertical direction, the actual vertical thickness a of the snow accretion I of the wire 5 can be calculated and measured.
Therefore, the measuring device 3 determines the number of pixels in the vertical direction of the snow accretion I photographed in the image, and calculates and measures the vertical thickness a of the snow accretion I of the wire 5 based on the above relationship. do.

Similarly, the measuring device 3 calculates the number of pixels in the horizontal direction of the icing snow I photographed in the image, and calculates the horizontal thickness b of the icing snow I of the wire 5 based on the above relationship. Calculate and measure.
The measuring device 3 measures the thicknesses a and b of the icing snow I on the electric wire 5 for all images of the ice and snow I on the electric wire 5 and stores them in the memory 33 .

The measurement device 3 can be configured to display the measured thicknesses a and b of the icing snow I at each location on the electric wire 5 on the display screen 34 according to instructions from the operator or the like. In addition, the measurement device 3 measures the state of the ice and snow I (icing and snow) adhering to the electric wire 5 photographed by the photographing device 20 as described above (the electric wire 5 is frozen and the cross section of the ice or snow I is elliptical). ) can be displayed on the display screen 34 .
In this way, if the thicknesses a and b of the accreted snow I and the state of the adhered ice and snow I are displayed on the display screen 34, the operator can see the measurement results and images of the states. , it is possible to check the state of the icing and snow I on each electric wire 5, that is, how much ice and snow I are adhering to each electric wire 5 and in what state.

[Sag calculation step]
On the other hand, when the measurement device 3 receives the image data D of the image (see, for example, the image 10 in FIG. As the second measurement for measuring the amount of icing and snowing, the sag degree d of the electric wire 5 is calculated based on the transmitted image data D and the like in order to measure the icing and snow weight Wi on the electric wire 5, which will be described later. (sag calculation step (step S4)).

Hereinafter, the calculation of the sag degree d of the electric wire 5 and the amount of icing/snowing on the electric wire 5 (icing/snowing weight Wi ) in an easy-to-understand manner, first, in the first embodiment, the case of measuring the amount of ice and snow accreted on the electric wire 5 under windless conditions or conditions that can be regarded as windless will be described.
Then, in the second embodiment, a case of measuring the amount of ice and snow on the electric wire 5 under the condition where the wind is blowing will be described.

[First embodiment]
[How to calculate sag d]
A method for calculating the degree of slackness d of the electric wire 5 described below is described in detail in Japanese Patent Application Laid-Open No. 2000-324639 and Japanese Patent Application Laid-Open No. 2002-112421.
Further, the following description is based on the image 10 shown in FIG.

The measuring device 3 first obtains the viewing angle range R of the image 10 .
That is, for example, with respect to the image 10 displayed on the display screen 34 of the measuring device 3, the worker or the like can measure the left and right tip portions of the cross arms 72C to 72E of the steel tower 62 photographed in the image 10. are indicated by touching the screen with a predetermined pointer or the like, their coordinates (x, y) on the image 10 are calculated. The measurement device 3 may be configured to automatically extract the left and right tip portions of each of the arm portions 72C to 72E from the image 10 and determine their coordinates.

For example, since the actual distance between the left and right tip portions of the cross arm portion 72E is known from the structural drawing of the steel tower 62, the actual distance between the tip portions is expressed as the difference in the x-coordinate between the tip portions. By dividing, the actual length per pixel in the x-axis direction can be obtained.
Then, from the calculated actual length per pixel in the x-axis direction, the actual length from the left end to the right end in the x-axis direction of the image 10 can be obtained.

Similarly, for example, the actual distance between the right tip portion of the arm portion 72C on the image 10 and the right tip portion of the arm portion 72E on the image 10 is also known from the structural drawing of the steel tower 62. Therefore, the actual height per pixel in the y-axis direction can be obtained by dividing the actual distance between the tips by the y-coordinate difference between the tips.
Then, the actual height from the top end to the bottom end of the image 10 in the y-axis direction can be obtained from the calculated actual height per pixel in the y-axis direction.

The measuring device 3 thus obtains the viewing angle range R of the image 10, that is, the area of the image 10 at the position of the steel tower 62 (the actual length in the horizontal direction and the actual height in the vertical direction).
By obtaining the viewing angle range R of the image 10 in this way, the power transmission line construction technology study group published "TLT-5 overhead line construction work" in October 1987 with Denki Shoin Co., Ltd. The sag degree d of the electric wire 5 can be calculated by applying the different length method of the sag calculation method described on page 228 of "Standard Reference Manual".

That is, the supporting point of the electric wire 5 on one of the steel towers 61 (in this case, the cross arm portion 71A of the steel tower 61 (see FIG. 1)) and the photographing device 20 of the aircraft 2 that has photographed the image 10 (in this case, the above h1 is the actual height difference between the lowermost cross arm portion 71E of one of the steel towers 61 as shown in FIG.
In addition, the support point of the electric wire 5 on the other steel tower 62 (in this case, the cross arm portion 72A of the steel tower 62 (see FIG. 1)) and the sag bottom 5a of the electric wire 5 (see FIG. 6) from the imaging device 20 Let h2 be the actual height difference between an observation point on the viewing angle range R of the image 10 when viewed through (the point slightly above the cross arm 72E of the other steel tower 62 and indicated by the arrow 5a). .

Then, in this case, according to the different length method, the relationship of the following formula (1) is established between the slackness d (see FIG. 7) of the electric wire 5 and the height differences h1 and h2. .

In this case, the height difference h1 can be seen from the structural drawing of the steel tower 61. FIG. Moreover, the above height difference h2 is the observation point on the viewing angle range R of the image 10 when looking through the sag bottom 5a of the electric wire 5 from the imaging device 20 and the cross arm on the image 10 (see FIG. 6). The number of pixels in the y-axis direction between the observation point and the arm portion 72D is determined, and the number of pixels in the y-axis direction is multiplied by the actual height per pixel in the y-axis direction to determine the actual height in the y-axis direction between the observation point and the arm portion 72D. It can be calculated by adding the actual height between the arm portions 72A-72D.
In addition, the observation point on the viewing angle range R of the image 10 when looking through the sag bottom 5a of the electric wire 5 from the photographing device 20 is indicated by an operator or the like by touching the screen with a predetermined pointer or the like. Alternatively, the measuring device 3 may be configured to automatically find out from the image 10 .

In this embodiment, the measurement device 3 determines the slackness d of the electric wire 5 based on the image data D and the like of the image 10 transmitted from the aircraft 2 as described above from the relationship of the above equation (1). It is calculated.

[Ice and snow amount measurement process]
Next, the measuring device 3 measures the amount of icing and snowing on the electric wire 5 (weight of icing and snowing Wi) on the electric wire 5 based on the sag d of the electric wire 5 calculated as described above (step of measuring the amount of icing and snow (step S5 )).
In this embodiment, the measuring device 3 calculates and measures the amount of icing/snowing (icing/snow weight Wi) on the wire 5 as follows.

If a current is flowing through the electric wire 5, the temperature of the electric wire 5 rises to 0° C. or higher, so ice or snow I does not adhere to the electric wire 5 (even if it does, it melts). The fact that ice or snow I adheres to the electric wire 5 means that no electric current is flowing through the electric wire 5 .
Therefore, it is considered that the temperature of the wire 5 to which ice or snow I is attached is the same temperature as the current air temperature T in the vicinity of the wire 5 .

Therefore, the measuring device 3 assumes that the temperature T of the electric wire 5 is the air temperature T measured near the electric wire 5 by the aircraft 2 in flight.
Subsequently, the measuring device 3 calculates the theoretical sag value di at that temperature T from the sag table for the electric wire 5 .

The slackness d of the wire 5 and the theoretical slackness value di are proportional to the load coefficient q of the wire 5 .
In general, the load coefficient q of the wire 5 is between each load on the wire 5 and
q=Ws/W={(W+Wi) ² +Ww ² } ^1/2 /W (2)
relationship is established.

Here, Ws is the combined load, W is the weight of the wire itself, Wi is the snow-covered load, and Ww is the wind pressure load (both units are kg/m). are in a relationship.
In the first embodiment, as described above, there is no wind or it can be assumed that there is no wind. ), and in this embodiment, the following formula (3) holds.
q=Ws/W=(W+Wi)/W (3)

Since the slackness d of the electric wire 5 calculated according to the above equation (1) is the sag of the electric wire 5 to which ice or snow I has adhered, the load coefficient q of the electric wire 5 represented by the above equation (3) is Proportional.
On the other hand, since the sag theoretical value di calculated from the sag table as described above is the sag of the wire 5 to which no ice or snow I adheres, the wire when Wi=0 in the above equation (3) It is proportional to the load factor q=W/W of 5 (ie 1 in this case).

for that reason,
d:di=(W+Wi)/W:W/W
∴Wi=W(d−di)/di (4)
By calculating , it is possible to calculate the snow/ice load Wi.
Therefore, in the present embodiment, the measuring device 3 calculates the current slackness d of the electric wire 5 based on the above equation (1) as described above, and obtains the theoretical slackness value di at the temperature T from the slackness table. Once determined, information on the weight W of the electric wire 5 is obtained from the power transmission line information 33b, and is substituted into the above equation (4) to calculate and measure the ice/snow load Wi, that is, the amount of ice and snow accreted to the electric wire 5. can be configured as

[Second embodiment]
Next, in a second embodiment, a case will be described in which the amount of ice and snow deposited on the electric wire 5 (load of ice and snow Wi) is measured in a windy situation.
When the wind is blowing, the relationship between the load coefficient q of the electric wire 5 and each load including the load of ice and snow Wi is as shown in the above equation (2) and FIG. θ in FIG. 8 represents the angle formed by the composite load Ws and the weight W of the electric wire 5 or the load Wi of covered ice or snow, that is, the angle of inclination of the electric wire 5 with respect to the vertical direction.

Then, as shown in the above equation (2), when calculating the snow/ice load Wi in a windy situation, in addition to the current load coefficient q2 of the wire ₅ and the self-weight W of the wire 5, Information on the wind pressure load Ww is required.
Therefore, as a method of calculating and measuring the load of ice and snow Wi when the wind is blowing, for example, it is possible to configure as follows.

In the same manner as the image 10 (see FIG. 6) was captured in the first embodiment, the image 11 as shown in FIG. The slackness d ^* of the electric wire 5 is calculated using the image 11 in the same manner as when the slackness d of the wire 5 is calculated.
Note that the slackness d ^* of the electric wire 5 in this case is similar to the slackness d shown in FIG. The actual height difference h1, the support point of the electric wire 5 on the other steel tower 62, and the observation point on the viewing angle range R of the image 10 when looking through the sag bottom 5a of the electric wire 5 from the imaging device 20 It is calculated based on the above equation (1) using the height difference h2.

However, when the wind is blowing and the wire 5 is inclined as shown in FIG.
The slackness d ^* of the electric wire 5 calculated as described above is the slackness calculated by focusing on the height difference, that is, the slackness calculated by focusing only on the vertical component. It corresponds to the original vertical component of the slackness d of the electric wire 5 . That is, the calculated slackness d ^* of the electric wire 5 does not include the horizontal component of the slackness d of the electric wire 5 .

Therefore, using the inclination angle ^θ of the electric wire 5 in FIG.
d ^* =d cos θ
∴d=d ^* /cos θ (5)
There is a relationship

Therefore, the image 11 (see FIG. 10) captured by the imaging device 20 of the aircraft 2 is image-analyzed to determine the inclination angle θ of the electric wire 5 with respect to the vertical direction.
In this case, for example, the image 11 may be photographed a plurality of times, and the average value of the inclination angle θ of the electric wire 5 calculated based on each image 11 may be used as the inclination angle θ of the electric wire 5. is.

Then, the calculated inclination angle θ and the calculated slackness d ^* of the electric wire 5 are substituted into the above equation (5) to calculate the original slackness d of the electric wire 5 (the current slackness d of the electric wire 5).
Next, the measuring device 3 measures the amount of icing and snowing on the electric wire 5 (weight of icing and snowing Wi) on the electric wire 5 based on the sag d of the electric wire 5 calculated as described above (step of measuring the amount of icing and snow (step S5 )).

In the present embodiment as well, the measuring device 3 determines the temperature T of the electric wire 5 as the air temperature T measured near the electric wire 5 by the aircraft 2 that has flown. Determine the degree theoretical value di.
The sag d and the theoretical sag di of the wire 5 are proportional to the load coefficient q of the wire 5, and the relationship between the load coefficient q of the wire 5 and each load including the icing/snow weight Wi against the wire 5 is given by the above equation There is a relationship of (2). The theoretical sag value di of the electric wire 5 described in the sag table is the sag when the weight of accreted snow and ice Wi=0.

Therefore, taking the ratio of the sag d of the electric wire 5 and the sag theoretical value di,
d: di={(W+Wi) ² +Ww ² } ^1/2 /W: (W ² +Ww ² ) ^1/2 /W
is established,
Wi={(W ² +Ww ² )d ² /di ² -Ww ² } ^1/2 -W (6)
becomes. Therefore, the ice and snow load Wi can be calculated by calculating the above formula (6).

However, in order to calculate the above formula (6), information on the wind pressure load Ww is required.
Therefore, it is possible to calculate the wind pressure load Ww on the wire 5 by measuring the wind speed at the position of the wire 5 with a wind speed sensor or the like mounted on the flying object 2 and calculating the wind pressure on the wire 5 based on it. .
It is also possible to configure the controller 21 to determine the wind speed of the outside air from a control value or the like when the drive controller 23 controls the rotor blades 23a so that the flying object 2 is not blown away by the wind.

Specifically, when the wind speed is V, the wind pressure P against the wire 5 is
P=0.5C×ρV ² (7)
is represented by
Here, ρ is the air density, which is 0.125 under standard conditions although it varies depending on atmospheric pressure and temperature. It should be noted that the present air density ρ may be calculated by measuring atmospheric pressure and temperature.

Also, Cx is a resistance coefficient, which is a value determined by the air flow around the wire. That is, when the air flow is laminar, it is approximately constant at about 1.1, but when the air flow becomes turbulent, it becomes about 0.9 to 1.0.
Therefore, the resistance coefficient Cx may be determined by the operator from an image of the electric wire 5 captured by the imaging device 20 of the aircraft 2 and input to the measuring device 3 .

Of the thicknesses a and b (see FIG. 5) of the icing snow I of the wire 5 measured as described above, the length a in the vertical direction is subjected to wind pressure. The wind pressure load Ww can be calculated by multiplying the wind pressure P calculated by the following formula (8) by the vertical length a of the accreted snow I (for example, its average value aave).
Ww=Paave (8)

Therefore, in this embodiment, the measuring device 3 first calculates the current slackness d of the electric wire 5 based on the above equations (1) and (5). Then, the sag theoretical value di at the temperature T is calculated from the sag table, and information on the dead weight W of the electric wire 5 is obtained from the power transmission line information 33b. Then, the wind pressure load Ww is calculated as described above.
By substituting these values into the above equation (6), the measuring device 3 can be configured to calculate and measure the ice/snow load Wi, that is, the amount of ice/snow accretion on the wire 5 .

In addition, if the wind pressure load Ww=0 in the above formula (6),
Wi = (W ² d ² /di ² ) ^1/2 -W
If this is transformed, it becomes the same equation as the above equation (4) for calculating the snow/ice load Wi when the wind is not blowing.

Therefore, as described above, it is not necessary to distinguish between cases in which the wind is blowing and cases in which it is not blowing. ) can be calculated.
Further, the measurement device 3 is configured to display the measurement result on the display screen 34 to notify the worker or the like when the amount of ice and snow accretion to the electric wire 5 (load of ice and snow Wi) is measured.

As described above, according to the system 1 for measuring the amount of ice and snow on overhead power transmission lines and the method for measuring the amount of ice and snow on overhead power transmission lines according to the present invention, a worker or the like flies the aircraft 2 and uses the photographing device 20 to When the electric wire 5 or the like is photographed, the measuring device 3 automatically calculates the slackness d of the electric wire 5 based on the image data D transmitted from the aircraft 2, and based on the calculated slackness d of the electric wire 5 The amount of ice and snow accreted to the wire 5 (load of ice and snow, Wi, etc.) is automatically measured.
Therefore, since the operator can measure the amount of ice and snow on the electric wire 5 without going to the electric wire 5 and the steel tower 6 to be measured, it is possible to easily measure the amount of ice and snow on the electric wire 5. becomes.

Further, there is no need to go deep into the snowy mountains or climb the steel tower 6 covered with ice or snow to observe the icing and snowing I on the electric wire 5, and the aircraft 2 can be flown from near the site. Since it is possible to measure the amount of ice and snow on the electric wire 5, it is possible to quickly measure the amount of ice and snow.
Therefore, in an emergency such as when a short-circuit accident occurs, it is possible to quickly measure the amount of ice and snow on the electric wire 5 and quickly observe the condition of the electric wire 5 and the like.

As described above, in the above-described embodiment, the measuring device 3 measures the thicknesses a and b of the accreted snow I at each location on the electric wire 5, Wi) is measured.
Therefore, it is possible to calculate the specific gravity of the accreted snow I on the electric wire 5 using such information.

Specifically, the measurement device 3 measures the vertical direction of the icing/snow I at each location of the electric wire 5 calculated based on the image data D of the electric wire 5 photographed by the imaging device 20 of the aircraft 2, as described above. The average value aave of the thickness a is calculated, and the average value bave of the thickness b in the horizontal direction is calculated.
Assuming that the cross-sectional shape of the icing snow I adhering to the electric wire 5 is an ellipse with a vertical diameter of aave and a horizontal diameter of bave as shown in FIG. teeth,
S=π×aave×bave−π×r ² (9)
Calculated by Note that r represents the radius of the electric wire 5 .

Therefore, the measurement device 3 calculates the cross-sectional area S of the accreted snow I according to the above equation (9), multiplies it by the length of the electric wire 5 (or the distance between the steel towers 6), and determines the accreted snow I on the electric wire 5. Calculate the volume Vo of
Then, the specific gravity s of the accreted snow I can be calculated by dividing the amount of icing/snow accumulating on the wire 5 (load of icing and snow Wi) calculated as described above by the calculated volume Vo. .

As described above, based on the average values aave and bave of the vertical thickness a and the horizontal thickness b of the icing snow I, and assuming that the cross-sectional shape of the icing snow I is elliptical, the icing snow Instead of calculating the volume Vo of I, it is also possible to calculate the volume Vo of the accreted snow I on the wire 5 more accurately based on the image data D.
Conventionally, the information on the specific gravity of the accreted snow I on the electric wire 5 was obtained by measuring the ice and snow dropped from the electric wire 5 with a hydrometer or the like. 1 and the method of measuring the amount of icing and snowing on overhead transmission lines, the operator does not need to remove the icing and snowing I from the electric wire 5, and the icing and snowing I can be measured while the electric wire 5 is still covered with ice and snow. It becomes possible to calculate and measure the specific gravity s.

It goes without saying that the present invention is not limited to the above-described embodiments and the like, and can be modified as appropriate without departing from the gist of the present invention.

1 system for measuring the amount of ice and snow on overhead transmission lines 2 flying object 3 measuring device 5 electric wire (overhead transmission line)
5a Sag bottom 6 Steel tower 20 Photographing device 61 One steel tower 62 The other steel tower a Vertical thickness of icing and snow b Horizontal thickness of icing and snow D Image data (image data)
d sag di theoretical sag I icing/snow accretion s specific gravity of icing/snow accumulating T temperature, air temperature V wind speed Vo volume of icing/snow accumulating wi ice load (amount of icing/snow accumulating on overhead transmission line)
Ww Wind pressure load

Claims (7)

A system for measuring the amount of icing and snow on an overhead transmission line, comprising:
an aircraft carrying an imaging device;
a measuring device that measures the amount of ice and snow accretion on the overhead power transmission line;
with
The flying object captures an image of the overhead power line with the imaging device while flying, and transmits data of the captured image to the measurement device,
The measuring device calculates the sag of the overhead power transmission line based on the transmitted data of the image, and calculates the amount of ice and snow on the overhead power transmission line based on the calculated sag of the overhead power transmission line. A system for measuring icing and snow accretion on an overhead power transmission line. The flying object includes the sag bottom of one of the two steel towers on which the overhead power transmission line is stretched, from a predetermined height position on the side of the other steel tower and the overhead power transmission line. 2. The system for measuring icing and snow on an overhead transmission line according to claim 1, wherein the overhead transmission line is photographed in such a manner. The measuring device has a sag table in which temperatures and theoretical sag values are associated with each other. and based on the sag of the overhead power transmission line calculated based on the data of the image and the theoretical sag value calculated from the sag table, the amount of ice and snow accreted on the overhead power transmission line is calculated. 3. The system for measuring icing and snow accretion on an overhead power transmission line according to claim 1, wherein the measurement is performed by The measuring device further calculates the wind pressure load on the overhead power transmission line based on the wind speed at the position of the overhead power transmission line measured by the flying object, and calculates the wind pressure load on the overhead power transmission line based on the calculated wind pressure load. 4. The system according to claim 3, wherein the amount of ice and snow is calculated and measured. The measuring device measures the vertical thickness and horizontal thickness of the icing and snowing on the overhead power transmission line based on the images of the overhead power transmission line taken by the imaging device from the lateral direction and the vertical direction. The system for measuring ice and snow on an overhead transmission line according to any one of claims 1 to 4, characterized in that: The measuring device calculates the volume of the icing and snowing on the overhead power transmission line based on the data of the image of the overhead power transmission line, and compares the calculated volume with the measured icing and snow on the overhead power transmission line. 6. The system for measuring the accretion of ice and snow on an overhead power transmission line according to claim 1, wherein the specific gravity of the accretion of ice and snow is calculated based on the amount. A method for measuring the amount of icing and snowing on an overhead transmission line, comprising:
a photographing step of photographing the overhead power transmission line with the photographing device while an aircraft equipped with the photographing device flies;
a transmission step of transmitting the data of the captured image to the measuring device;
a slackness calculation step in which the measurement device calculates the sagness of the overhead power transmission line based on the data of the transmitted image;
an icing/snowing amount measuring step of measuring the amount of icing/snowing on the overhead transmission line based on the calculated sag of the overhead transmission line;
A method for measuring icing and snow accretion on an overhead transmission line, comprising:

Images