Centre for Science and Technology for Development
Advanced Technology Assessment System
Table 1: Costs of Alternatives for an 8-gW Transmission Line over 2400 km ($109)
The Brasilian hydro potential located in the south, southeast and northeast regions will soon be exhausted. Low-cost. large-scale hydro resources are in the major right-bank tributaries of the Amazon River, but these are in the north and far distant from The population centres. Roughly 100 gW can be developed at a relatively low cost ($44/MWh, including long distance transmission), which is competitive with the alternative of building smaller hydro, coal and nuclear plants near the load centres. By the year 2010, large blocks of power (20 to 25 gW) may be transmitted over distances up to 2,400 km from the north to the other regions.
Planning studies and economic evaluations were performed considering application of ultra-high voltage AC and DC. One result Of the present-worth cost estimation for the transmission of a power block of 8 gW over 2,400 km is summarized in Table 1. Investment cost includes substation and line costs for each optimized system (two bipoles for the DC alternatives, and three series and shunt-compensated lines for the AC case). The cost of losses refers to equipment and joule and corona Line losses. The new technology of +/-800-kVDC has the lowest total cost.
Conclusions and Recommendations
A developing country must decide how it will tap its primary energy resources. Should electricity be transported to existing load centres or should industrial development be promoted at or near the generation sites? Should electricity be restricted to specific sites Or should it be dispersed based on alternate energy sources? Answers will vary by country, because they relate more to economics than to the electrical System planning, and to the nature and size of the energy resources.
Now, more than ever, it is important for developing countries to start a concerted effort to bridge the technology gap. One of the major fields where this could take place is in energy technology, affecting the way transmission technologies are introduced in the developing nations-the problems are there to be solved and the electric utility Industry is one of the few organizations that can tackle the problems. Such effort might include:
- joint ventures in R&D,
- demonstration programmes, and
- equipment nationalization on a regional level.
To reduce the gap, in addition To local or regional R&D incentives and either north-south or south-south co-operation, a new kind of human resource is needed, deep commitment to regional development and acquisition of the adequate technical knowledge.
The origins of the electrical system, American and/or European, and the lack of financial resources needed to face the large investments in the expansion Of the transmission system, coupled with the availability of suppliers and other international financing, brought to developing countries a mix of influences and, as a result, both European and American standards are sometimes in use in the same region, the same country and even the same grid. A common example is the different frequency standards used in South America, which hinder the interconnections between neighbouring countries. A regional power industry development effort might alleviate such problems, and increase the chances for the future build-up of continental power pools, at least in South America. Some African nations are already electrically interconnected, but technology is usually supplied from European countries that still hold substantial control over the technological development of their former colonies.
- Developing countries have both the need and, roost often, the natural resources for the expansion of their electrical Systems.
- Due to the incipient state of their industrial development, much is still to be done and electricity rates of growth are high.
- The attractive part is that they can still make technological choices because their electrical Systems are in an early stage of development.
- The distribution of natural resources, away from the main load centres, and of population in and around major cities in the country suggests large investments in the design and construction of long-distance/high-capacity power transmission trunks.
- There is also a need to improve and expand electricity distribution networks at the destination, in major cities and in industrial regions.
- Electric power research and development must be a concern of developing nations, because in many cases they have both the problems and engineering skills To Solve the problems.
- As the power system expands, it becomes more complex to operate and, as a consequence of the delayed investments, more prone to suffer from power failures. A further consequence is the operation at reduced safety margins, i.e., closer to the limits of both equipment and facilities.
- There is no way to decouple power system expansion from large amounts of financing needs. Even if electricity conservation measures, which have their own costs, reduce the rate of investments in generation and transmission, the latter will still be needed in the future.
- The major question that remains is how to finance the needed expansion. Electricity rate increases are limited by the buying power of the population and, sometimes, by the need to curb inflation growth; therefore they cannot be the sole source of power expansion funds. The question becomes even more difficult if the borrowing potential of the country-access to international financing from world/regional organizations and other governments-is severely restricted by already existing foreign debt. As a result, investments in construction and operation of generation and transmission facilities are not always compatible with the needs of the country.
We recommend a few measures To ease the path to improving the country's industrial development and attending to the social needs of the population.
- Achieve technological development through in-house research or Joint ventures (or informal associations) with industrial nations (vertical technical co-operation) or other countries under development (horizontal co-operation). For instance, develop a working knowledge of local and regional meteorological and other conditions to produce adequate transmission system design. Such Joint ventures/associations may take the form of R&D or demonstration programmes.
- Invest in power system planning and operation methodology. Using modern software for expansion planning and systems operation leads to substantial savings by either maximizing returns on new projects or delaying future investments.
- Look at the local/regional industrial park organizations, using the buying power of the utility industry to boost the number and quality of products in the country.
- The countries must make good use of their utility industries' buying potential, in more than one sense. They might for instance, preserve their power expansion markets for local industrial development.
- Practice, as much as possible, realistic electricity tariffs, for both the industrial/commercial and residential consumers.
UHV AC Transmission System (>1,000 kV)
Belyakov. N. N., L. M. Bortinil, and A. F. Djakov,
"1,200-kV Transmission Line in the U.S.S.R.: The
First Results of Operation," CIGRE (1988 Session).
Morrissy, C. A., A. Vian, J. M. Bressane and A. V. Ferraz, "1,000-kVAC Alternatives for the 8 gW/2,400 km Transmission System from the Amazon Basin to the South-Eastern Region," Workshop on Very Long Distance AC Transmission Systems, Pisa (1984).
Compact Transmission Lines
Hajdu, E. M., R. Cardoso and F. Teiveilis, "Evaluation
of Various Conductor Support Systems for 1,500-kV
Transmission Lines," CIGRE Open Conference
Study Committee 22, Rio de Janeiro (1983).
Higher Phase Order Transmission
Grant, I. S., et al., "Higher Phase Order Transmission
Line Research, "CIGRE Symposium, Stockholm,
Guyker, W. C., "Six-phase Protection Hurdle Cleared," Electrical World (Jan. 1981).
Stewart, J. R. et al., "HPO Line Practical for Limited R/W," Transmission and Distribution (Oct. 1985).
Half-wave-length Power Transmission
Lepecki, J., et al., "Half-wave Transmission,"
Eletrobas Special Project no. 9, Rio de Janeiro
Prabhakara, F. S., K. Partharathy, and H. N. Ranachandra, "Analysis of Natural-Half-wave-length Power Transmission Lines", and "Performance of Tuned Half-wave-length Power Transmission Lines," IEEE (Dec. 1968)
Pouel, C. O., "Half-wave Transmission," VI SNPTEE, Santa Catarina (1981).
UHV DC Transmission System (+/-600-kV)
Campos Barros, J. G., S. O. Frontin, J. A. Jardini
and L. B. Ries, "Engineering Studies for HVDC Above
+/-600-kV with a View to its Applications to the Transmission
of Large Blocks of Power over Very Long Distance,"
HVDC Converter Stations for Voltages Above +/-6OO-kV: Engineering Studies, EL 3892, Electric Power Research Institute, Palo Alto, California (Feb.1985).
HVDC Converter Stations for Voltages Above +/-6OO-kV: R&D Needs and Priorities, EL 4984, Electric Power Research Institute, Palo Alto, California(Dec. 1986).
Krishnayya, P. C. S., et al., "Technical Problems Associated with Developing HVDC Converter Stations for Voltages Above +/-600-kV," IEEE, V. PWRD-2,1 (Jan. 1987).
Krishnayya, P. C. S., et al., "An Evaluation of the R&D Requirements for Developing HVDC Converter Stations for Voltages above +/-600-kW,"CIGRE (1988 Session).
Le Du, A., "The French Experience in the Multiterminals
DC Links," IEEE/CSEE Joint Conference on High
Voltage Transmission Systems, Beijing(Oct. 1987).
Lee, R. L., et al., "Enhancement of AC/DC System Performance by Modulation of a Proposed Multiterminal DC System in the Southwestern U.S.," IEEE Transactions on Power Delivery, V. 3, 1 (Jan. 1988).
Shira, D., et al., "Interconnection of Isolated Communities in Southeast Alaska by HVDC," Symp. on Urban Applications of HVDC Power Transmission, Philadelphia (Oct. 1983).
Shunt and Series HVDC Taps
Carpaneto. E., et al., "Small Power Tapping from
HVDC Transmission Systems," CIGRE, Paris (1986
Krishnayya, P. C. S., et al., "Simulator Study of Multiterminal HVDC System with Small Parallel Tap and Weak AC System," IEEE/PES 1984 Winter Meeting, Dallas (Jan. 1984).
Morissy, C. A., et al., "Some Aspects of the Energy Supply to Small Loads Located Near Long Distance Transmission Trunks," CIGRE, Paris(1986 Session).
Clark, H. K., and F. P. Melo, "Enhancement of
AC Systems by Application of DC Technology," First
Symposium of Specialists to Electrical Operational
Planning, Rio de Janeiro (Aug. 1987).
Krishnayya, P. C. S., et al., "A Review of Unit
Generator Converter Connections for HVDC Transmission,"
IEEE/CSEE Joint Conference, Beijing(Oct. 1987).
Denman, O. S., et al., "A Microwave Power Transmission
System for Space Satellite Power," and G. M. Hartley,
"Evolution of Satellite Power System Concepts",
both at 13th Intersociety Energy Conversion Engineering
Conf., United States (1978).
Itaipu Transmission Project
Peaxow, C. A. 0., "Itaipu 6,300 MW HVDC Transmission
System Feasibility and Planning Aspects," Symp.
Incorporation HVDC Power Transmissionin System Planning,
Phoenix (Mar. 1980).
Madzarevic, V., C. A. 0. Peixoto, and L. Hagloef, "General Description and Principal Charicteristics of the Itaipu HVDC Transmission System," Proc. International Symposium on HVDC Technology, Rio de Janeiro (Mar. 1983).
Email this page to a friend
If you speak another language fluently and you liked this page, make
a contribution by translating
it! For additional translations check out FreeTranslation.com
(Voor vertaling van Engels tot Nederlands)
(For oversettelse fra Engelsk til Norsk)
(Для дополнительных переводов проверяют FreeTranslation.com )