Publications

Engetower’s team is pleased to contribute to research and to the development of the sector

In addition to carrying out its technical activities, Engetower team is always willing to share knowledge and exchange experiences, contributing to research and to the qualification of professionals in the area. Through regular participation in seminars and conferences, the technical solutions developed by the company are presented, as well as the practical results of implementation in specific projects.

Latest Publications

(XXIV SNPTEE – NATIONAL SEMINAR FOR ELECTRIC POWER PRODUCTION AND TRANSMISSION - 10/2017)
Jean Mark Carvalho Oliveira, Filipe Guerra Soares, Paulo Ricardo R. Liberato da Silva, Pedro Henrique de O. Liberato, Sírio José Ferreira, Reynaldo Castriota de Mello, Tadeu Rezende, Ricardo de O. and B. Perucci, Tiago Corradi Mello
This Technical Bulletin describes Engetower Engenharia e Consultoria’s challenges developing software for tridimensional detailing modeling (3D) for the fabrication and assembly of trussed towers for transmission lines. The stages of a tower design are briefly presented and the usual process of bidimensional detailing (2D) with its difficulties, simplifications and advantages is emphasized. From that information, the 3D modeling, which consists in one of the stages of the BIM technology, is presented to show pursued objectives, some of the implementation difficulties, the platforms adopted, the main advantages and the results achieved.

Request full-text PDF
(XXII SNPTEE - NATIONAL SEMINAR FOR ELECTRIC POWER PRODUCTION AND TRANSMISSION - 10/2013)
Marcos César de Araújo, José Henrique Machado Fernandes, Paulo Henrique Barbosa Naves, Filipe Guerra Soares, Paulo Ricardo Ralo Liberato da Silva, Reynaldo Castriota de Mello, José Luiz Nunes Michelini Filho, João Félix Nolasco, Kleber Ribeiro dos Santos
This Technical Bulletin addresses the main aspects, stages and conclusions of the technical and economic study developed by Eletrobras Eletronorte, Leme Engenharia and Engetower Engenharia to define the conducting wire and structural solution for the Lechuga – Equator 500 kV TL and the Equator – Boa Vista 500 kV TL. That study preceded the project’s Basic Design development stage in order to previously define the main parameters of those lines. 5 types of conducting wires and 2 structural solutions were selected for the development of a complete comparative economic study, including the definition of the appropriate condition of mechanic traction of cables, the definition of the structure geometry and their preliminary location within an estimated profile. From those definitions, the forecasted quantities and costs regarding the different components of the TLs were obtained and it was possible to identify the most attractive alternative both from the economic and the technical aspects. That solution was used in the project.

Request full-text PDF
(XXII SNPTEE - NATIONAL SEMINAR FOR ELECTRIC POWER PRODUCTION AND TRANSMISSION - 10/2013)
Amaury Saliba, Evandro P. Magalhães, Paulo Ricardo R. L. Silva, Mário Noburu Takai
The connection between the Amazon and the National Interconnected System-SIN through the construction of the Transmission Line that links the Tucuruí HPP to Manaus is being studied by ELETROBRAS ELETRONORTE since 1986 as a means to connect the Isolated Systems to SIN and to replace oil thermal generation, consequently reducing the emission of greenhouse gases. Several studies analyzed the more feasible and less impacting technical options, considering the possible criteria to prevent the Transmission Line from passing through corridors having legal protection areas, especially Indigenous Land and Conservation Units, besides minimizing interferences on urban centers and Preservation Areas with natural forest cover, meadow and other ecosystems. Once the Amazon Region and its environmental assets have a global importance, the implementation of any project in that region becomes a considerable challenge and requires the most care as well as suitable technologies as for the construction of Transmission Lines and Substations to minimize the interferences with the social and environmental system. Within that context, this bulletin aims at describing some implementation phases regarding the Oriximiná / Manaus 500 kV TL, special attention being given to a 300- km stretch that was outlined based on the Amazon River, its tributaries and arms, which led to logistic challenges and to most structures having river access, and the need for careful planning in comparison to the classic transmission line construction forms, mainly due to the hydrological conditioning factors imposed by the Amazon Region.

Request full-text PDF
(XX SNPTEE - NATIONAL SEMINAR FOR ELECTRIC POWER PRODUCTION AND TRANSMISSION - 2009)
Kleber Ribeiro dos Santos, João Félix Nolasco, Hilton Antônio de Melo, Elilson Eustáquio Ribeiro, Alexandre E. Mendes Meloni, Filipe Guerra Soares, Paulo Ricardo R. Liberato da Silva, Reynaldo Castriota de Mello, Sírio José Ferreira, Ricardo Martin, Rogério de Campos Vieira
The Brazilian electric power sector is going through an exceptional phase with high investment on power generation and transmission. The interconnection of important areas in the northern region (Rondônia, Acre, Amazonas and Amapá) to the rest of the National Interconnected System (SIN) is part of that context. Auctions carried out by ANEEL have considered those interconnections. An intensive search for engineering solutions is being promoted in order to achieve maximum efficiency aiming at the lowest possible cost for the project. In ANEEL Auction No. 005/2006, Jauru Transmissora de Energia S.A., a consortium formed by COBRA, ELECNOR and ISOLUX, was granted the concession for the 230 kV TLs that are going to interconnect the states of Rondônia and Mato Grosso, connecting Samuel, Ariquemes, Ji-Paraná, Pimenta Bueno, Vilhena and Jauru substations with single and double circuit TL stretches. Thus, Jauru Transmissora and designer houses Leme Engenharia and Engetower Engenharia looked for integrated engineering solutions that would meet the electric parameters required by ANEEL and the features of each TL stretch and also that would allow for achieving the return rates aimed at by investors. The companies involved in the project developed the basic design, the electric studies, the structural solution and the electromechanical design that would be more suitable to the technical and economic needs of the project. For the double circuit line, 230 kV TL Vilhena – Jauru, a new series of suspension Danube type towers was developed. The typical suspension tower is cable-stayed with a two-triangular-circuit configuration. This Technical Bulletin describes electric, mechanic, structural and economic aspects of this unique design solution and presents some of the results obtained from using it in the transmission line referred to.

Request full-text PDF
(XX SNPTEE - NATIONAL SEMINAR FOR ELECTRIC POWER PRODUCTION AND TRANSMISSION - 2009 - 2009)
Filipe Guerra Soares, Paulo Ricardo R. Liberato da Silva, Reynaldo Castriota de Mello, Sírio José Ferreira
Prior to series production of structures for Transmission Lines, prototype full-scale Load Tests are often carried out to assess the reliability of the structural designs. During such tests, the more significant load hypotheses are applied to the structures in stages and load/strain measurements represent data related to structure behavior during the test. Studies that combine results from several Load Tests to theoretical statistic models concluded that a Log-Normal type function with mean and standard deviation around 105% and 9% of the theoretical resistance, respectively, would be appropriate to describe structure strength. Those results, combined to the methodology in IEC 60826 standard [4], lead to the use of a coefficient for minor strengths equals to 0.93 for structures submitted to Load Tests so that the strength with an exclusion limit of 10% of such structures is always above the load applied. This Technical Bulletin presents the assessment of the results regarding 9 destructive Load Tests carried out on structures designed by Engetower Engenharia whose collapses took place in stages from 115% to 155% of the design load. The discrepancy of those values comparing to the studies mentioned above took to the analysis of the results and to the conclusion that the value of the strength coefficient used should be reassessed, also evidencing the need to set forth criteria and conditions for the approval of Load Tests.

Request full-text PDF
(XIX SNPTEE - NATIONAL SEMINAR FOR ELECTRIC POWER PRODUCTION AND TRANSMISSION - 2007)
Filipe Guerra Soares, Paulo Ricardo Ralo Liberato da Silva, Reynaldo Castriota de Mello, Sírio José Ferreira, Luiz Eduardo Marcílio
The construction of Transmission Lines by reusing existing tower designs has been a well disseminated practice in Brazil. The spans and the angles for the application of each structure are adjusted to the specific conditions of the location where the TL is going to be set. For those adjustments, the impact of front winds is usually considered according to load criteria proposed by IEC 60826 or by NBR 5422. Within that context, ENERSUL purchased designs from CEMIG of a series of towers for single circuit 138kV lines developed in 1982 with climate parameters and application characteristics that are specific for the concession area of the company in the state of Minas Gerais. Such designs were then used in the construction of the Single Circuit 138kV Transmission Line Paraíso SPP / Chapadão do Sul having an extension of 54km and energized on December 27, 2003. Interruptions to the TL were registered on June 03 and October 16, 2004. They were a result of the structural collapse of towers during strong windstorms associated to hail storms. In the face of those early failures, it was necessary to double check the structural reliability of the TL and also to carry out studies to define the probable causes of the collapses. This Technical Bulletin presents the studies developed in the structural analyses in order to define the probable causes of the above mentioned collapses, their main results and the resulting conclusions and recommendations.

Request full-text PDF
(XIX SNPTEE - NATIONAL SEMINAR FOR ELECTRIC POWER PRODUCTION AND TRANSMISSION - 2007)
Vanderlei Guimarães Machado, José Henrique Machado Fernandes, Marcos César de Araújo, Mário Noboru Takai, Ricardo Alexandrino Vasconcelos, Antônio Pessoa Neto, Ruy Barbosa Pinto Jr, Filipe Guerra Soares, Paulo Ricardo R. Liberato Silva, Reynaldo Castriota de Mello, Sírio José Ferreira
The current environment in the Brazilian electric sector, with the legal opening to private projects and especially with the implementation of the auction system to define concession holders of Transmission Lines to be built, has been fostering a healthy competition among engineering companies in that sector by developing design solutions that are economically advantageous in regards to the electric, mechanic and structural performances due to the incorporation of technological innovations. In that context, ELETRONORTE, CHESF and ENGETOWER developed studies for the use of a monopole cat head cable-stayed structure with expanded beam on the 500 kV TL North / South III Interconnection - Stretch 2, with an extension of 525 km, a concession of INTESA - Integração Transmissora de Energia S.A., a partnership consisting in Eletronorte, Chesf, Engevix and Fundo de Invest. Part. Brasil Energia, which won the ANEEL auction in the end of 2005. This Technical Bulletin describes electric, mechanic and structural aspects of that design solution and presents some comparative results regarding the optimization study with the V cable-stayed solution with expanded beam and the Cross-rope solution.

Request full-text PDF
(XVIII SNPTEE - NATIONAL SEMINAR FOR ELECTRIC POWER PRODUCTION AND TRANSMISSION - 10/2005)
Luiz Alkimin de Lacerda, Paulo Alexandre de Oliveira, Amanda Jarek, Carlo Giuseppe Filippin, Borys Wictor Dagostim Horbatiuk - LACTEC, Francisco Gris Liberato Marcolino, Valdir Cerqueira Petersen - AMPLA, Paulo Ricardo Ralo Liberato da Silva - ENGETOWER
In this paper, the studies carried out in order to build a reduced model of a suspension tower are described for the static and dynamic structural tests to be performed. The reduced model is defined so that the critical situations related to the prototype can also be seen and evaluated for the reduced model. The limitations in the fabrication of structural parts such as equal leg angle irons in reduced sizes are presented, as well as their possible impact on the test results. The static tests followed the specifications in standard NBR-8842/85 and the results were compared to the tower prototype load test measurements and to the computer results.

Request full-text PDF
(XVIII SNPTEE - NATIONAL SEMINAR FOR ELECTRIC POWER PRODUCTION AND TRANSMISSION and XI ERIAC - ENCUENTRO REGIONAL IBERO AMERICANO DEL CIGRE - 2005)
Vanderlei Guimarães Machado, Camilo Machado Júnior, José Henrique Machado Fernandes, Marcos César de Araújo, Mário Noboru Takai, Filipe Guerra Soares, Paulo Ricardo Ralo Liberato da Silva, Reynaldo Castriota de Mello, Sírio José
The current environment in the Brazilian electric sector, with the legal opening to private projects and especially with the implementation of the auction system to define concession holders of Transmission Lines to be built, has been fostering a healthy competition among engineering companies in that sector by developing design solutions that are economically advantageous in regards to the electric, mechanic and structural performances due to the incorporation of technological innovations. In that context, ELETRONORTE and ENGETOWER developed studies for the use of a monopole cable-stayed structure with expanded beam on the single circuit 230 kV TL Cuiabá / Rondonópolis, with an extension of 171 km, in the state of Mato Grosso, a concession of AETE - Amazônia - Eletronorte Transmissora de Energia S.A., a partnership consisting in Eletronorte, Alubar, Encomind, Linear Participações and Bimetal, which won the ANEEL auction in the end of 2003. This Technical Bulletin describes electric, mechanic and structural aspects of that design solution and presents some of the comparative results obtained from its application to the transmission line referred to.

Request full-text PDF
(XVIII SNPTEE - NATIONAL SEMINAR FOR ELECTRIC POWER PRODUCTION AND TRANSMISSION - 2005)
Filipe Guerra Soares, Paulo Ricardo Ralo Liberato da Silva, Reynaldo Castriota de Mello, Sírio José Ferreira, Evanildo Ramos Ribas, Kleber Ribeiro dos Santos, João Felix Nolasco
ANEEL bidding processes for the concession of transmission lines, open to the participation of private companies, promoted an intense search for engineering solutions focused on maximum efficiency understood as the lowest possible project cost including installation, losses and risk of penalties applied by the inspection departments. Thus, in regards to the structures, a highly representative component in line cost and reliability, the participant companies have been making an effort to develop innovative solutions or to improve the traditional ones so that they bring competitive advantages into the projects in which they take part. In that context, Companhia Transleste de Transmissão S/A, a partnership consisting in ALUSA, CEMIG, FURNAS and ORTENG, which won the concession contract for the Montes Claros 2 - Irapé 345 kV TL (an extension of 138.5 Km) in an auction carried out by ANEEL in the end of 2003, with a discount of 34% on the maximum annual revenue allowed, looked for a structural solution that attended to all the electric parameters required in ANEEL bidding documents and that would allow for achieving return rates aimed at, despite the high discounts. LEME, JFNOLASCO and ENGETOWER were then engaged to develop the electric studies, the studies for the optimization of a monopole cat head cable-stayed structural solution, the basic design, the structure executive design and the TL electromechanical design, all of them adjusted to the technical and economic needs of a successful project. This Technical Bulletin describes the electric, mechanic, structural and economic aspects related to this design solution and presents some of the results obtained from its application to the transmission line referred to.

Request full-text PDF
(XVII SNPTEE - NATIONAL SEMINAR FOR ELECTRIC POWER PRODUCTION AND TRANSMISSION - 01/2003)
Claiton A. R. Homrich /em>
This paper presents AES South’s experience in the use of 69 kV compact metal structures in its transmission system in urban areas. That kind of use allowed for a significant reduction to the final costs compared to the concrete structures usually used in areas with high population density. In addition to that, the practice substantially reduced the size of the structures, lessening the visual impact due to the construction of the towers. Relevant aspects of the tower design are listed, cost reductions are detailed and illustrations show the reduction of the visual pollution due to the use of the structures.

Request full-text PDF
(XVI SNPTEE - NATIONAL SEMINAR FOR ELECTRIC POWER PRODUCTION AND TRANSMISSION - 2001)
Amaury Saliba, Jaime de Oliveira, José Henrique M. Fernandes, Mário Noboru Takai, Erivelto Gomes Regueiro, Paulo Ricardo R. Liberato Silva, Reynaldo Castriota de Mello, César Augusto Luccas, Túlio Pavanello Junior
This Technical Bulletin aims at reporting the experience acquired from the installation of an additional OPGW (Optical Ground Wire) cable in ELETRONORTE’s compacted energized 500 kV Imperatriz / Presidente Dutra Transmission Line, with an extension of 385 Km. Some technical and economic aspects are initially presented in regards to the definition of comparative costs related to the implementation to an energized line switched off, as well as comments and results referring to the feasibility analyses as for the electric and mechanic/structural performance. After that, design criteria adopted and design details of the OPGW cable fastening devices are described. Then, short reports on field assembly tests, on the OPGW cable laying design process and on the results obtained are presented. To conclude, some findings that came up along the implementation of OPGW cables in compact energized TLs are listed.

Request full-text PDF
(XIV SNPTEE - NATIONAL SEMINAR FOR ELECTRIC POWER PRODUCTION AND TRANSMISSION - 1997)
Amaury Saliba, Mário Noboru Takai, Sílvio Caldas, Paulo Ricardo R. Liberato Silva, Reynaldo Castriota de Mello, João Batista G. Ferreira da Silva, Rogério Peixoto Guimarães
This Technical Bulletin reports design and construction aspects of the single circuit, 69 kV TLs, SE Distrito Industrial - SE’s Reman / Gillette / Videolar, located in the Industrial sector in Manaus-AM, total extension of 3589 m, using constant section trussed steel structures TRUSSPOLE type (Figure 1). Initially, the basic overall characteristics that guided line design are presented, as well as the criteria adopted in the definition of the different kinds of structures used. After that, the main results obtained during the executive process are listed. To conclude, comments are made regarding the application of that design solution to low tension urban TLs.

Request full-text PDF
(XIII SNPTEE - NATIONAL SEMINAR FOR ELECTRIC POWER PRODUCTION AND TRANSMISSION - 10/1995)
PAULO RICARDO RALO LIBERATO DA SILVA, REYNALDO CASTRIOTA DE MELLO, SÍRIO JOSÉ FERREIRA, MÁRCIA AUGUSTA DE MOURA CADETE, MAURO DIAS DE SOUZA, ROBERTO PIRES DANTAS
The bulletin reports the origin, development and results of the application of the TRUSSPOLE. It is a spatial trussed structure with a single steel foundation that is similar to a wooden or a concrete pole and that is able to associate the technical and economic advantages of the trussed structures to the ones of the massive or tubular poles. The report is on the results obtained from the design, the load tests for an initial study prototype and the construction of a 53.2 km 69 kV S.C. TL using that kind of structural solution.

Request full-text PDF
(ERLAC – CIGRE’S REGIONAL LATIN AMERICAN MEETING - 05/1993)
JOÃO BATISTA G. FERREIRA SILVA*, PAULO RICARDO R. LIBERATO DA SILVA, VILSON RENATO DA SILVA
An optimized transmission line design has to consider the strong influence of climate and landscape conditions. Thus, a line is closely connected to the area for which it was designed. Within that context, it is reasonable to think that transmission line structures (or even complete lines) are elements that cannot be standardized for the different regions under penalty of compromising targeted performance and/or economy indexes. In Brazil, however, as time went by, transmission line systems multiplied, were interconnected and lines that crossed different geographic regions appeared. Another interesting fact is that, for the same region, designs that were implemented in different periods presented quite different results due to technological progress and the experience acquired in the construction and operation of the previous systems. The result in Brazil was that TL designs for different regions in different times started to have very similar traits, especially in regards to the structures. In addition to those findings, another fact that led to the possibility of thinking about standardizing transmission lines was the way the electric power marketplace organized itself. For political, economic and social reasons, the Brazilian electric system was structured by means of groups of companies with generating and transmitting characteristics, and other companies with a strong distributor profile. Obviously, there is also a group of companies that encompass both activities. Anyway, from a certain period on, numerous sub transmission and system interconnection lines started to come up. What frequently characterizes sub transmission is the large set of short extension lines. Short extension lines usually fail to justify specific designs for economic and timeframe reasons. Consequently, small-size companies with a power distributor profile are forced to use existing and often obsolete designs for their electric power sub transmission and distribution lines. In that context, the concept of standardization emerges as an interesting idea. This bulletin intends to describe how the commission created by ELETROBRÁS through COBEI to study the standardization of 69 and 138 kV structures has been working. The commission is still working. Nevertheless, important results and conclusions have already been obtained.

Request full-text PDF
(XI SNPTEE - NATIONAL SEMINAR FOR ELECTRIC POWER PRODUCTION AND TRANSMISSION A - 10/1991)
JOÃO FÉLIX NOLASCO, JOÃO BATISTA GUIMARÃES FERREIRA DA SILVA, LUIZ ANTÔNIO RALO LIBERATO DA SILVA, PAULO RICARDO RALO LIBERATO DA SILVA
A lot has been built in Brazil in the last twenty years in terms of transmission lines. From the north to the south of the country, many kilometers of lines were spread, crossing the most different climate and terrain regions. That set of lines built and currently in operation represents a large potential for experimental analysis, which can allow professionals working in the sector to produce more realistic designs for the lines to be built in the future. Existing lines follow up, as well as the creation of databanks from already installed climate stations, have encouraged designers to develop from the deterministic method to the probabilistic method as a basic philosophy for the design of new lines. In that context, undesirable system failures may, on the other hand, offer an extraordinary opportunity to analyze and assess what was previously being done in comparison to what is done nowadays. That is doubtless an excellent exercise to consolidate what to be done in the future. This bulletin intends to show an analysis of the accident involving 2 cable-stayed structures for 500 kV transmission lines in CEMIG’s São Simão system.

Request full-text PDF
(X SNPTEE - NATIONAL SEMINAR FOR ELECTRIC POWER PRODUCTION AND TRANSMISSION - 10/1989)
JOÃO BATISTA GUIMARÃES FERREIRA DA SILVA, PAULO RICARDO RALO LIBERATO DA SILVA, JOÃO FÉLIX NOLASCO, LEOVERGILDO ROSETE DIAS
One of the marking trends in the current electric systems by power authorities translates into the reuse of existent transmission lines for larger capacities. The increasing difficulty to obtain new easement areas, added to scarce resources for new investment, make reuse, may it be by reinsulating or reconducting existing lines, a quite attracting solution. The renovation of old lines, till then usually based on replacing damaged or compromised elements, has to be seen from a wider perspective to increase the efficiency rate (MW/m) of the easement. The introduction of IEC/CIGRÉ statistic methods for the calculation of transmission line structure loads and the use of failure risk criteria, associated to wind return periods, came to be a valuable tool for the technical and economic evaluation of reuses. It is obvious that statistic methods themselves were not representative when providing more safety or less risk for a transmission line. However, the designer who has information on the strategic importance of a certain line for the transmission system as a whole can decide how to better reuse it, in terms of safety and reliability, by coordinating the possibility of component failure. Finally, one can say that, by adopting statistic methods, we started working with calculated risk classes and current wind values, which allows for more optimized designs and, regarding reuse studies, more opportunities to requalify the lines.

Request full-text PDF
(3º ELARC - CIGRE’S REGIONAL LATIN AMERICAN MEETING - 08/1989)
J.B.G.F.SILVA, P.R.R.LIBERATO SILVA, J.F.NOLASCO
Longitudinal imbalance loads have been a recurring study subject for the current CIGRÉ’s WG Groups - 06 – Reliability and Safety of Transmission Lines and WG - 08 - Structures for Transmission Lines. The main questions regard the way the problem is assessed, the values to be considered, the level of load uncertainty and the effects they may have on structures. Dynamic tests have been carried out in some countries, but very little could effectively been concluded so far. However, conducting cables have shown to be the safest components in a transmission line system. The occurrence of broken conductors has been low, although cascade falls have quite frequently taken place, especially in countries where high wind speeds are common. The attempt to justify those failures leads to the investigation of the structures’ longitudinal strength, which generally depends on it as a basic load for sizing, although not necessarily associated to the rupture of the conductor. A comparative analysis of the longitudinal and cross strength of certain structures reveals that there may be a big difference between them. That happens mainly for suspension towers in lines with a tension of 500 kV and above, when such structures are self-supporting. On saving purposes, those towers tend to be rectangular, with less longitudinal strength. Not correctly considering oblique and/or longitudinal wind pressures on those towers may lead to an underestimated longitudinal loading. That inaccurate evaluation, associated to the smaller structure strength to that direction, ends up by suggesting a critical and apparently unforeseen failure situation, even if the conductor is not broken. Situations such as that one may happen in Brazil where, in the recent past, structures were projected and the latest IEC recommendations were not applied. This paper intends to clarify the situation by assessing a structure model that is sensitive to the questioning above.

Request full-text PDF
(3º ELARC - CIGRE’S REGIONAL LATIN AMERICAN MEETING - 05/1989)
P.R.R.LIBERATO SILVA, J.B.G.F.SILVA, C.R.GONTIJO
A lot has been discussed recently on the use of folded plate profiles on structures for transmission lines. From the first prototypes carried out in Europe and the review of publication no. 52 of the American Society of Civil Engineering, in which the use and sizing of such profiles were also included, that subject became recurring in CICRÉ’s WG-08-Structures Work Group meetings. In philosophical terms, the issue may be addressed from a logical and rational perspective: it is the shape of each profile that is suitable for each use condition in special. However, from that logical conclusion, in a more detailed discussion on how to manufacture the structures, that apparently theoretically unlimited possibility bumps into fabrication limits and into gauge and process standardization criteria that cannot be avoided in the industrial system. Those partly antagonistic conditions start to converge to a balance position that ultimately represents the current market situation in which technically feasible and economically competitive structures start to appear. In Brazil, a lot has been asked in the last two years on the possibilities and/or advantages of developing designs for transmission line structures using those cold-formed profiles. The main questions regard the criteria to be used in sizing, the kind of profile and steel to be used, the adjustment of Brazilian manufacturers to that new product, the raw material storage issues, and the possible savings from the perspective of the Brazilian reality. The answers to those questions could only be obtained from the execution of a real design. The materialization of this pioneer project is being led by CIGRÉ Brasil’s GT-08 – Structures Work Group. That study is in its final conclusion stage. That is what follows.

Request full-text PDF
(IX SNPTEE - NATIONAL SEMINAR FOR ELECTRIC POWER PRODUCTION AND TRANSMISSION - 10/1987)
J. B. G. F. SILVA, L.A.R.L. SILVA, R.C. MELLO - MENDES JÚNIOR INDUSTRIAL LTDA.
Overhead transmission lines in urban areas has become more and more frequent. That is due to two main reasons. First of all, transmission lines built in the past to feed substations near cities are nowadays totally incorporated to the urban landscape. The city grows and takes up the areas surrounding the line and, in some cases such as slums, even the easement. On the other side, as a result of the increasing demand, it is necessary to build sub transmission lines that interconnect incoming substations to distribution ones. For the implementation of such urban lines, the aspects related to interaction with the environment become the most relevant ones and require careful studies where visual impact, safety and compaction evaluations play an important role. Monotube steel structures proved to be excellent supports for those specific transmission lines. In what regards the system for connection to the foundation, two classical solutions have been adopted: directly setting the pole to the soil by means of concrete and the use of base plates with anchor bolts. The first solution is usually more advantageous from an economic standpoint, but it makes grading and/or the application of cambers to angle structures more difficult. It is important to say that those poles are quite flexible structures. On the other hand, direct setting makes it almost impossible to replace a damaged structure. The second solution is technically perfect, although it is expensive for the Brazilian marketplace conditions. This bulletin reports experimental tests carried out to an intermediate kind of connection to the foundation, which is as cost efficient as direct setting and as versatile as the anchor bolt solution. It is a concrete box system with water consolidated sand that is confined by means of a seal. The bulletin reports the test system and development, the results obtained from a structural and strain point of view and the final conclusions of the test.

Request full-text PDF
(IX SNPTEE – NATIONAL SEMINAR FOR ELECTRIC POWER PRODUCTION AND TRANSMISSION - 05/1987)
P. R. R. L. SILVA, J. B. G. F. SILVA
In the end of the 70’s, a lot was being discussed on the use of angle irons in the metric series for the fabrication of steel structures in Brazil. The publication of Brazilian standard no. 6109 in 1983 and the resulting offer of millimeter graduated iron angles by steelmakers intensified the discussions on the necessary adjustments regarding existing designs using inch graduated profiles, the criteria to be developed for new designs, the cost efficiency in terms of new structure weights, as well as the current availability of profiles. The conclusions and answers to these questions could only be obtained by executing a real design. Nonetheless, it was difficult to materialize that pioneer project due to commercial market conditions, raw material storage, private commercial interests and even the inertia of sectors involved. It was necessary that a power authority, Companhia Energética de Minas Gerais, through a specific bidding process, required structures to use profiles adopting the metric system. This bulletin presents the result of the first standard structure design for 138 kV single circuit TL using profiles in the metric series available in the Brazilian marketplace. Difficulties faced during the supply as well as the consequences on the calculations, design, fabrication and inspection are addressed.

Request full-text PDF