JP7619456B2 - Apparatus, method and program for calculating pole unbalanced load - Google Patents

Description

This disclosure relates to technology for eliminating unbalanced loads that occur on poles, such as utility poles and signal poles, due to differences in the installation conditions of cables, such as power lines and telephone lines, that are installed on poles that are primarily outdoors.

Traditionally, when installing a pole, the resultant force of the tension generated by the cable to be installed on the pole and the load of other accessories is taken into consideration. This results in a resultant load acting on the pole (unbalanced load). The type of pole to be used is then determined based on this unbalanced load, including the effects of uncertain factors such as wind pressure strength and soil hardness.

Design loads are set for each type of pole as a standard for the allowable load, and when the designer actually constructs the pole, they select a pole with a design load that can withstand the unbalanced load mentioned above, taking into account the effects of uncertainties such as the strength of wind pressure and the hardness of the soil. Also, depending on the direction of the unbalanced load, guys and supports may be installed in a direction that offsets the unbalanced load to prevent the pole from collapsing. In this way, the unbalanced load acting on the pole is assumed depending on the magnitude and direction of the tension generated by the cable to be laid, and the type of pole to be used is determined so that this unbalanced load does not cause deformation of the pole or cracks that could lead to its destruction.

Currently, it is assumed that the unbalanced load on the pole will not change from the design conditions (magnitude, direction) except when a new cable is laid. However, in reality, uneven construction or exposure to the external environment over time can cause the unbalanced load conditions to worsen from the design conditions, raising the risk of the pole deforming or cracking, which could lead to destruction. Such unbalanced loads and the resulting deformation and cracks in the pole are currently discovered through regular inspections, but in many cases the only solution is to upgrade to poles with a larger design load, which incurs huge upgrade costs.

In addition, in some cases, work is carried out to eliminate unbalanced loads by changing the cable slack if there is excess cable length, or by changing the pole position if site negotiations are possible, but in actual construction, the extent to which the unbalanced load will be eliminated by changing the slack or pole position is not calculated, but is determined on-site at the time of construction. Currently, when attempting to evaluate unbalanced loads, the cable tension is calculated using the tension T (kN), cable load per unit length w (kN/m), span length S (= distance between cable installation positions) (m), actual cable length L (m), and cable slack d (m) (see non-patent document 1).

JP 2020-98126, "Equipment status detection device, equipment status detection method, and program" (NTT)

"Sag of Overhead Transmission Lines", Hideyo Takeshita, published September 15, 1966

In theory, it is possible to calculate the amount of change in span length required to adjust the tension as desired, but in reality, when the tension in the span changes, the unbalanced load changes, causing the pole to deform and the span length to change, which will not match the tension calculated previously.

The purpose of this disclosure is to make it possible to calculate the change in unbalanced load on a pole when the cable installation conditions are changed.

Therefore, this disclosure takes advantage of the fact that the cable tension differs depending on the cable installation conditions, and is characterized by evaluating the unbalanced load on the pole before and after changing the cable installation conditions by formulating the balance of forces acting on the pole.

The apparatus and method according to the present disclosure include:
When the cable installation conditions are changed, the pole on which the cable is installed is considered as the target pole,
The tension of each cable installed on the target pole and the unbalanced load on the target pole are calculated.

The program of the present disclosure is a program for causing a computer to realize each functional unit of the device of the present disclosure, and is a program for causing a computer to execute each step of the method performed by the device of the present disclosure.

According to the present disclosure, it is possible to calculate the change in the unbalanced load on the pole when the cable installation conditions are changed, and to determine the cable installation conditions that eliminate the unbalanced load.

FIG. 13 is a flow diagram of the process for eliminating an unbalanced load performed by the device of the present disclosure. FIG. 11 is an explanatory diagram of information required for calculating cable tension. FIG. 1 is an explanatory diagram of mechanical elements acting on a pole. 11A and 11B are explanatory diagrams showing examples of deformation of a pole. FIG. 13 is a flow chart of an example of convergence calculation of a force balance equation. FIG. 13 is an explanatory diagram of feedback to cable tension T as a result of changes in pole deformation Δ. FIG. 13 is an explanatory diagram of an image of eliminating an unbalanced load by changing the actual length. An example of the relationship between cable tension T and actual length L is given below. FIG. 13 is an explanatory diagram of an image of eliminating unbalanced load by changing the span length. FIG. 13 is an explanatory diagram of an image of eliminating unbalanced load by changing the sag. 1A and 1B are diagrams illustrating examples of the effects of changing the cable installation conditions (actual length, span length, slack, etc.) of a facility system, where (a) shows the state before the cable installation conditions are changed, and (b) shows the state after the cable installation conditions are changed. FIG. 13 is an explanatory diagram of an example of an unbalanced load generated on a pole. 1A and 1B are examples of connection configurations between a pole and a cable, where (a) shows a retaining connection and (b) shows a pulling connection. FIG. 2 is a functional block diagram of the first embodiment. FIG. 11 is a functional block diagram of a second embodiment.

Below, the embodiments of the present disclosure will be described in detail with reference to the drawings. Note that the present disclosure is not limited to the embodiments shown below. These implementation examples are merely illustrative, and the present disclosure can be implemented in various forms with various modifications and improvements based on the knowledge of those skilled in the art. Note that components with the same reference numerals in this specification and drawings are considered to be identical to each other.

(Example 1)
A functional block diagram for implementing this embodiment is shown in FIG. 14. The device according to this embodiment includes an unbalanced load calculation unit 12 and a cable installation condition calculation unit 13. A method implemented by the device according to this embodiment is shown in FIG. 1. In the device according to this embodiment, the unbalanced load calculation unit 12 calculates the unbalanced load acting on the pole (S11), the cable installation condition calculation unit 13 determines the cable installation conditions (actual length, span length, slack, etc.) for eliminating the unbalanced load (S12), and determines an implementation method for realizing the above cable installation conditions (actual length, span length, slack, etc.) (S13). The device of the present disclosure can also be realized by a computer and a program, and the program can be recorded on a recording medium or provided via a network. A detailed description will be given below.

First, step S11 will be described. In order to calculate the unbalanced load acting on the pole 91, it is necessary to calculate the tension of the cable 92 laid on the pole 91. Figure 2 illustrates the conditions required to calculate the tension of the cable 92 laid between two poles 91. Here, T represents the tension (kN), w represents the load of the cable 92 per unit length (kN/m), S represents the span length (i.e., the distance between the laying positions of the poles 91) (m), L represents the actual length of the cable 92 (m), and d represents the slackness of the cable 92 (m). At this time, the tension T generated in the cable 92 is expressed by formula (1) or formula (2).

Here, w is a numerical value specified for each cable 92 to be laid. S, L, and d represent the laying conditions of the cable 92. An example of a method for measuring S, L, and d is to obtain and calculate three-dimensional point cloud data in which the surface of the cable 92 is represented by points in three-dimensional coordinates (see Patent Document 1).

Next, step S12 will be described. Specifically, a method for determining cable installation conditions (actual length, span length, sag, etc.) for eliminating the unbalanced load based on the calculated unbalanced load will be described. Fig. 3 shows the mechanical elements acting on a pole 91, including tensions _T1 , _T2 , ... of a cable 92 installed on the pole 91 and a reaction force F caused by deformation of the pole 91 due to the unbalanced load. The balance of forces between these forces can be considered as shown in the following formula (3).
(Equation 3)
(ΣT _n )+F=0 (3)

Equation (3) can be considered for each pole 91. In addition, the reaction force F caused by the deformation of the pole 91 due to the unbalanced load can be considered as in equation (4).
(Equation 4)
F = f(Δ) (4)
Here, Δ represents the deformation of the pole 91 and can be expressed, for example, by the head displacement 83 of the pole 91 (FIG. 4). The head displacement 83 can be calculated, for example, from the horizontal distance between the vertical axis 81 of the pole 91 and the cable installation position 82.

In this case, it is considered that each element of the formula (3) when the cable installation conditions (actual length, span length, sag, etc.) are changed is calculated from the formulas (1), (2) and (4).
The flow for determining the cable tension T and unbalanced load after changing the cable installation conditions (actual length L, span length S, sag d, etc.) is shown in Fig. 5. The cable tension when the cable installation conditions (actual length, span length, sag, etc.) are changed can be calculated from the formula (1) or (2) using the changed actual length L, span length S, and sag d (Fig. 5, step b).
On the other hand, since the unbalanced load changes due to the change in the tension of the cable 92, the reaction force F of the pole 91 also changes (F'), which can be calculated from the formula (3) (FIG. 5, step c).

At this time, the pole reaction force changes to F', which also changes the "pole deformation Δ" (step d in Figure 5). Now consider the effect on the tension T of cable 92 of the change in pole deformation Δ. For example, if we consider the horizontal distance (= head displacement 83) between the "vertical axis 81 of the pole from the ground" and the "cable installation position 82" as the "pole deformation Δ", then "head displacement 83 = change in span length" (Figure 6), and based on the changed span length, the tension T of cable 92 is recalculated using equation (1) or equation (2) (step e in Figure 5).

At this time, the convergence of the balance equation is judged by equation (5) using the tension of cable 92 and the reaction force of pole 91 obtained from steps c and e of FIG. 5 (step f of FIG. 5).
(Equation 5)
(ΣT _n )+F≦A (5)

Here, A is a threshold value for determining convergence and is set to a sufficiently small value. Calculations are repeated until equation (5) is satisfied (Figure 5-c→d→e→f→c...).

The cable tensions _T1 ', _T2 '... when equation (5) is satisfied can be considered as the cable tensions after a change in the cable installation conditions (actual length, span length, sag, etc.), and using this, the unbalanced load after a change in the cable installation conditions (actual length, span length, sag, etc.) can be calculated as shown in equation (6).
(Equation 6)
Unbalanced load = (ΣT _n ') (6)

Here, the convergence calculations in FIG. 5 can be considered as a group of calculations, and can be considered as a function g that calculates the “unbalanced load on the pole” from the “changed cable installation conditions (actual length, span length, sag, etc.)” (Equation (7)).
(Equation 7)
(Unbalanced load on the pole) = g (changed cable installation condition) ≦ B (7)

Here, B is a threshold value that is sufficiently small. By determining the cable installation conditions (actual length, span length, sag, etc.) that satisfy equation (7), it is possible to calculate the cable installation conditions (actual length, span length, sag, etc.) required to eliminate the unbalanced load.

The above series of steps can be considered as function h that calculates "cable installation conditions (actual length, span length, sag, etc.) after the unbalanced load is eliminated" from "unbalanced load on the pole" (equation (8)).
(Equation 8)
(Cable installation condition after unbalanced load is eliminated) = h (unbalanced load on pole) (8)

There are multiple cable installation conditions (actual length, span length, sag, etc.) that satisfy equation (8) depending on the calculation conditions, so we will describe the optimal cable installation conditions and how to actually achieve them.

First, we will consider the actual construction methods for changing the parameters of the cable installation conditions, namely actual length, span length, and slack, in steps S31 to S33 below.

Step S31: Change in actual length Consider the elimination of the unbalanced load by "changing the actual length of the high tension span." Since the actual length and tension of the cable 92 are inversely proportional (Equation (2) and FIG. 8), it is possible to eliminate the unbalanced load by "extending the actual length of the high tension span." Therefore, the unbalanced load can be eliminated by increasing the actual length to the result calculated by Equation (8).

Specifically, as shown in Figure 7, a member 71 is inserted into the connection between the pole 91 and the cable 92 to increase the actual length L of the cable 92. By preparing members 71 of multiple lengths and selecting the appropriate member 71, it is possible to achieve the desired increase in actual length L. This method can also be implemented when there is no interference from other accessories 73 such as metal fittings at the connection between the pole 91 and the cable 92 (= the bridge position), the connection between the pole 91 and the cable 92 is in a "retaining" form (Figure 13(a)), and the cable 92 has excess length. When the connection between the pole 91 and the cable 92 is in a "retaining" form, the support 72 of the cable 92 is divided into the left and right sides of the pole 91 and is connected to the pole 91 via other accessories 73.

Step S32: Changing the span length Consider resolving the unbalanced load by changing the position of the pole 91. The unbalanced load can be resolved by moving the pole 91 to a position that satisfies the cable installation conditions (actual length, span length, sag, etc.) calculated by formula (8) (Fig. 9). This method can be implemented if the conditions such as cable slack, negotiations with the landowner, and the ground conditions at the new position are met.

Step S33: Changing the sag Consider the elimination of the unbalanced load by changing the sag. When there is an excess length of the cable 92 at the cable fixing point of the pole 91, the sag can be changed using the excess length of the cable 92 as in the cable installation conditions (actual length, span length, sag, etc.) calculated by formula (8), thereby realizing the elimination of the unbalanced load (FIG. 10). This construction method can also be implemented when there is no obstruction from other metal fittings or other accessories 72 at the connection part (=laying position) between the pole 91 and the cable 92, the connection between the pole 91 and the cable 92 is "pulled through" (FIG. 13(b)), and the cable 92 has an excess length. When the connection between the pole 91 and the cable 92 is "pulled through", the support 72 of the cable 92 is not divided between the left and right sides of the pole 91, and is fixed to the pole 91 via other accessories 73.

In this way, whether the cable installation conditions (actual length, span length, slack, etc.) can be realized depends on the
(i) the state of the bridge position;
(ii) The connection form between the pole 91 and the cable 92 (pulling through, retaining),
(iii) the status of negotiations for surrounding land;
Varies depending on various conditions such as:

These can be collectively referred to as the "implementation conditions of the construction method", and can be specified as a function k that determines the "optimum cable installation conditions (actual length, span length, sag, etc.) and implementation method for eliminating the unbalanced load" from the "unbalanced load of the pole" and the "implementation conditions of the construction method" (Equation 9).
(Equation 9)
(Optimal cable installation conditions and implementation methods for eliminating unbalanced loads)
= k (unbalanced load of pole, construction method implementation condition)) (9)

As described above, the device and method according to the present embodiment include:
Step S1 of calculating the cable tension T based on the installation conditions of the cable 92 using formula (1) or formula (2);
Step S2 of calculating the reaction force F and the deformation amount Δ of the pole 91 based on the tension T of the cable 92 obtained by using the formulas (3) and (4);
Step S3: recalculating the tension T of the cable 92 based on the deformation amount Δ of the pole 91;
Step S4: determining whether the balance equation (5) converges based on the reaction force F of the pole 91 obtained in step S2 and the tension T of the cable 92 obtained in step S3;
If it is determined in step S4 that convergence has not occurred, steps S2 to S4 are repeatedly executed, and if it is determined that convergence has occurred, an unbalanced load on the pole is calculated based on the calculated cable tension in step S5;
As a result, the present disclosure can calculate the change in the unbalanced load on the pole 91 when the installation conditions of the cable 92 are changed, and can determine the installation conditions of the cable 92 that eliminate the unbalanced load.

(Example 2 of the embodiment)
A functional block diagram for implementing this embodiment is shown in Fig. 15. When the cable installation conditions (actual length, span length, sag, etc.) are changed to eliminate the unbalanced load, the tension of the cable installed on the adjacent pole also changes, so the effect of this can be considered by replacing the flow of step S12 in the first embodiment with the following:

The poles and the cables laid on those poles are collectively referred to as the "facility system," and an example is shown in Figure 11. In order to eliminate the unbalanced load on pole 91-3, consider changing the installation conditions of cable 92-3 between poles 91-3 and 91-4. The loads T1' and T2' of the cable laid on pole 91-3 resulting from changing the installation conditions of cable 92-3 between poles 91-3 and 91-4 can be considered as shown in formula (10).
(Equation 10)
(Tension of the cable laid on the pole 91-3: T1', T2')
= g (changed cable installation condition between poles 91-3 and 91-4) (10)

In this way, starting from pole 91-3 for which it is desired to eliminate the unbalanced load, the tension of the cable 92 laid on each pole 91 due to changes in the cable laying conditions (actual length, span length, sag, etc.) can be calculated in order. As a series of these calculations, a function j for calculating the unbalanced load on each pole of the facility system when the laying conditions (actual length, span length, sag, etc.) of a certain cable 92 are changed can be considered (Equation (11)).
(Equation 11)
(Unbalanced load on pole X) = j (changed cable installation condition) (11)

As in the first embodiment, by considering h as a function that calculates "cable installation conditions (actual length, span length, sag, etc.) after eliminating the unbalanced load" from "unbalanced load on the pole," it is possible to obtain the cable installation conditions (actual length, span length, sag, etc.) for eliminating the unbalanced load on a certain pole X in terms of an equipment system (Equation 12).
(Equation 12)
(Cable installation conditions after unbalanced load is eliminated)
= h (unbalanced load on pole X) (12)

(Effects of the present disclosure)
According to the present disclosure, it is possible to calculate how the unbalanced load generated in the pole 91 changes when the installation conditions (actual length, span length, slack, etc.) of the cable 92 connected to the pole 91 on which the unbalanced load is generated are changed.

Specifically, the balance of forces between the tension of the cable 92 connected to the pole 91 and the reaction force caused by the deformation of the pole 91 due to an unbalanced load can be considered as a mechanical element acting on each pole 91. In addition, by determining the relationship between the "tension of the cable" and the cable installation conditions (actual length, span length, sag, etc.) and the relationship between the "reaction force caused by the deformation of the pole due to an unbalanced load" and the displacement of the cable installation position on the pole (head displacement), it is possible to calculate the unbalanced load on the pole 91 before and after the change in cable installation conditions more accurately than before.

As a result of the above, it is possible to calculate what cable 92 installation conditions would be necessary to eliminate an unbalanced load when an unbalanced load occurs on the pole 91. This can also be used to consider materials and efficient construction methods to achieve the cable 92 installation conditions, contributing to the efficiency and cost reduction of current construction methods for eliminating unbalanced loads. Furthermore, from the perspective of early elimination of unbalanced loads, it can contribute to preventing future cracks and pole breakage, i.e., realizing long-term safe use of facilities.

This disclosure can be applied to the information and communications industry.

71: Member 72: Support 73: Attachment 91: Pole 92: Cable

Claims (3)

Calculating the tension of the cable when a member of a different length is inserted into the connection between the target pole and the cable, using the actual length of the cable and the reaction force caused by the deformation of the target pole;
Calculate the unbalanced load of the target pole using the calculated tension of the cable;
selecting an actual length of the cable at an appropriate unbalanced load among a plurality of unbalanced loads obtained by calculation as the actual length of the cable to be connected to the target pole;
Device. The device calculates the tension of the cable when a member of a different length is inserted into the connection between the target pole and the cable, using the actual length of the cable and the reaction force caused by the deformation of the target pole;
The device calculates the unbalanced load of the target pole using the calculated tension of the cable;
The device selects an actual length of the cable at an appropriate unbalanced load among a plurality of unbalanced loads obtained by calculation as an actual length of the cable to be connected to the target pole.
method. A step of calculating the tension of the cable when a member of a different length is inserted into the connection between the target pole and the cable, using the actual length of the cable when the member of a different length is inserted into the connection between the target pole and the cable, and the reaction force caused by the deformation of the target pole;
calculating an unbalanced load on the target pole using the calculated tension of the cable;
a step of selecting an actual length of the cable at an appropriate unbalanced load among a plurality of unbalanced loads obtained by calculation as an actual length of the cable to be connected to the target pole;
A program for causing a computer to execute the following .

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