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LP84 - AES Congress on Innovation, Technical Excellence and Sustainable Practices

Claiton Homrich

Engineer

AES Sul

Ismael Gonçalves

Eletrotecnical

AES Sul

Leonardo Câmara

Eletrotecnical

AES Sul

Abstract—Sustainability and Innovation, key words to de-

scribe what AES Sul has founded to solve their problems with

reduction of time, costs and resources for construction of trans-

mission lines.

The FRP (FIBERGLASS REINFORCED POLYESTER),

which is designed to replace wood, steel and concrete in building

structures for 69 KV proving to be an effective alternative.

The insertion of 69kV FRP structures showed a considerable

reduction in the final work cost resulting in approximately 25%

below if compare the cost necessary to install steel structures.

The reduction in costs is basically consequence to the small

size of the structures, requiring less volume of excavation and

backfill, once it is installed directly on the ground. In view of no

excavation necessity and no concrete use.

The structures also satisfy the improvements on the aesthetic

conception, theme with great topical interest, reducing then its

visual impact and also the environmental impact and sustainable.

Index terms--efficiency, innovation, sustainability, viability.

I. INTRODUCTION

RADITIONALLY, the most influential factor that affected

the decision to design the transmission line is cost-

effective. Currently, combined with cost reduction, it becomes

increasingly important to reduce the visual impact of the pro-

ject, because the environmental agencies and regulatory agen-

cies are becoming quite demand to release of building permits

Within this new context, AES Sul studied the feasibility of

inserting new technologies related to the transmission line 69

kV and 138 kV in their standard of materials and services for

transmission lines, seeking to reduce costs and time, while

maintaining its reliability. The result of this study was the use

of 69kV FRP structures in rural transmission lines.

II. DEVELOPMENT

The design of the transmission line was based on the criteria

of the Brazilian standard NBR 5422 - Design Overhead Trans-

mission and Sub-transmission Lines of Electric Power, and the

design of FRP poles, manufactured by the Petrofisa Ltda, was

calculated according to the load requested in the project, as

shown in Figure 1.

The transmission line used for the study, has an extension of

55,000 meters, voltage 69 kV, single-phase circuit with hori-

zontal configuration, 1 ACSR conductor LINNET 336.4 kcm

per phase, 2 cable arrester HS 3/8 " and porcelain insulators. To

build the transmission line were used 205 suspension structures

and 43 anchor structures.

Fig.1. Design of the FRP structure.

The regions, where this study was done for installation of

these structures, are characterized mostly by fields, farms and

rocky terrain, where all parameters satisfy the necessity of the

operation area of AES Sul.

The same load conditions of conductors and the lightning

arrester, as well as the same speed and wind pressure and same

pay-back period was used compared with an equivalent steel

structure transmission line.

A. Prototype

The next step was to build a prototype for installation in

AES Sul transmission lines. After the manufacturing of sup-

porter, and performed the inspection and monitoring of the

factory acceptance test, ensure the success in compare to the

study by the designer, and performing all tests requested by

Brazilian standards.

The installation was positive, both by assembly facilities as

well as acceptance by maintenance crews of AES Sul, giving

confidence to follow the project using FRP poles in AES Sul

transmission lines.

Fiberglass poles - use in transmission lines.

Technical-Economic advantage

T

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LP84 - AES Congress on Innovation, Technical Excellence and Sustainable Practices

B. Design of new transmission lines project

Considering an H-type structure with two poles, cross arm

and draught proofing, with a single pole foundation, similar to

wooden pole, associating technical economic advantages of

fiberglass structures with lattice structures.

C. Pole tests

C1. Routine bending test

The routine bend test was performed, reaching the limit es-

tablished by the project, as shown in Figures 2 to 5.

Figura 2 – Start of the test.

Fig. 3. Dynamometer with a minimum breaking load.

Fig. 4. Pole on the minimum braking load – side view..

Fig. 5. Pole on the minumum braking load – side view

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LP84 - AES Congress on Innovation, Technical Excellence and Sustainable Practices

C.2 Cable-stayed pole

The routine bending test was performed, using the coupling

rod on poles, simulating field characteristics, as shown in Fig-

ures 6 to 9.

Fig. 6. Pole on 858 daN bending load.

Fig. 7. Pole on minimum breaking load (2300daN).

Fig. 8. Pole on 1190 daN bending load..

Fig. 9. Dynamometer recording the load 2246 daN in bending test.

C.3 Pole test after burn

Test was performed on the entire pole after the burn of base

region (fire situation) according to the following conditions, as

shown in Figures 10 to 13:

− The flame (yellow) should be applied continuously for

1 minute;

− After the withdrawal of the flame, it must be extin-

guished within 30 seconds;

− Perform the bending test after the burn.

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LP84 - AES Congress on Innovation, Technical Excellence and Sustainable Practices

Fig. 10. Start of the pole burn in the base region.

Fig. 11. Base region shortly after the withdrawal of the flame.

Fig. 12. Base region 15 seconds after the withdrawal of the flame.

Fig. 13. Bending test after the burn

C.4 hoisting structure simulation

The 20-meters-hoisting was simulated to the complete

structure (approximate 2000 kg). The assembly time was 3

hours (2 people), and hoisting time was 3 minutes shown in

Figures 14 to 17.

Fig. 14. Assembly of the lied structure.

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LP84 - AES Congress on Innovation, Technical Excellence and Sustainable Practices

Fig. 15. Start of the hoist.

Fig. 16. Hoisted structure.

Fig. 17. Hoisted structure.

III. DESCRIPTION OF MATERIALS

A. Structures

With the insertion of this new concept of FRP structures for

transmission lines, we have a saving in materials and also ser-

vices. The steel structures were replaced by fiber poles.

Two of advantages to use these structures are transportation

and installation, as they are made of fiberglass and sectional,

using a small truck the parts can be moved anywhere.

Fig. 18. Load of poles.

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LP84 - AES Congress on Innovation, Technical Excellence and Sustainable Practices

For this transmission line, would be quite complex the in-

stallation of steel structures due to difficulty of access by con-

crete delivery trucks.

Fig. 19. Sectioning os the poles.

Fig. 20. Sectioning os the poles.

The activities take place directly at the workplace, which

may install and assemble the entire structure with a small

crane, as seen in Figures 18 to 20.

The union between the modules is made with the expansive

sleeve and inner link plate of the walls, so that the parts do not

suffer from vibration effects since this system does not transfer

the effort to the pin, turning the two walls in a single fiber piece

shown in Figures 21 to 26.

Fig. 21. Fixed model.

Fig. 22. Fixed model.

Fig. 23. Fixed model.

Fig.. 24 Fixed model.

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LP84 - AES Congress on Innovation, Technical Excellence and Sustainable Practices

Fig. 25. Fixed model.

Fig. 26. Assembly of the structure after completed connections.

For this transmission line was used 496 fiber poles, totaling

248 structures, of which no steel needed in foundations.

The material saving was not envisioned in this item, there

was an increase by 11%, but the assembly had about 3% reduc-

tion, just by reducing weight and ease of transport.

The major differential of reduction for this item was in the

foundation, by 84% reduction, which can be seen in table 1.

TABLE 1

COMPARASION OF VALUES.

B. Foundations

In this project was observed a difference practically in all

items of the structures foundation, such as excavation, con-

crete, backfill, steel armor, reused moulds, soil deposit, flexi-

ble conduit; no item listed above is used in the foundations of

FRP structures.

For all structures, the foundations follow basically the pat-

tern used for the wooden structures, which at the base of poles

is fixed two pieces of wood to length of 2.00 meters, as seen in

figures 27 and 28.

These parts are installed horizontally into each pit, and in

different depths, of 45 cm to the first piece and 65 cm to the

second, from the ground level.

Fig. 27. Foundation project.

Fig. 28. Installation of foundation.

C. Execution time

Another significant item for using this type of structure is

the time to install the foundations, which for a similar transmis-

sion line last 7 months on average. Using FRP structures, it was

performed 3 months on average, just for the facility of in-

stalling the foundation and assembly, as seen in Table 2.

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LP84 - AES Congress on Innovation, Technical Excellence and Sustainable Practices

TABLE 2

SCHEDULE OF EXECUTION;

D. Environmental and visual impact

The requirements of regulatory and environmental agencies

force to adapt to new concepts in environmental preservation

and in the case of urban areas, also the visual impact, as shown

in figure 29.

Fig. 29. FRP structure

Based on this, through the installation of FRP structures,

there was a reduction in cutting vegetation around the place to

assembly the FRP structures compared with the installation of

steel structures, facilitating the release of environmental licens-

es and consequently decreasing the final schedule.

E. Sustainability

This project had a significant reduction of all materials and

services used comparatively in foundations of the steel struc-

ture. No use of mineral resources such as steel and concrete,

and also preserve the integrity of soil, minimizing the excava-

tions. Table 3 shows the result of reduction of these resources.

TABLE 3

COMPARATIVE

IV. CONCLUSIONS

The conclusion that could be taken from this project was the

financial savings with the change of traditional steel structures

in rural transmission lines by the new concept of FRP struc-

tures.

Yet, the facility of installation and assembly, being installed

in places of difficult access for heavy equipment, reducing

execution time

After the conclusion of this project, there was an increase of

approximately 17% in material items, due to the greater num-

ber of structures, insulators and double ground wire, and reduc-

tion of approximately 48% of the service items, resulting in a

global savings approximately 25% and reduction of execution

time of approximately 37.5%.

After all these considerations, the lower visual impact and

sustainable, facility of installation and maintenance, shorter

execution time and less investment compared with the installa-

tion of metal structures, all objectives of this new concept of

69kV-FRP structures under the AES Sul were successfully

achieved, as shown in Figure 30.

Fig. 30. Transmission line with FRP.

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LP84 - AES Congress on Innovation, Technical Excellence and Sustainable Practices

V. REFERENCES

Standards: [1] Associação Brasileira de Normas Técnicas – Projeto de Linhas Aéreas

de Transmissão e Subtransmissão deEnergia Elétrica – NBR 5422 – Brasil.

Books: [2] Labegalini, P. R.; Labegalini, J. A.; Fuchs, R. D.; Almeida, M. T. “Pro-

jetos Mecânicos das Linhas Aérea.

[3] Marinucci, G. Materiais Compósitos Poliméricos. Ed. Artliber, 2011.

[4] Carvalho, A. Tosfac - Total Strain Failure Criterion. Ed. Artsim, 2009.

[5] Abmaco. Compósitos I – Materiais, Aplicações, Desempenho e Tendên-

cias. Ed. SLEA, 2008.

[6] Abmaco. Compósitos II – Processos. Ed. SLEA, 2009.

[7] Abmaco. Compósitos III – Processos. Ed. SLEA, 2010.