The Electricity Supply Industry and its impact on Transmission Line Technology – Economical Aspects

摘要

The transmission line technology of the future willbe able to meet the requirements of the electricitysupply industry by increasing the transmissioncapacity with the help of real-time monitoring of theconductor tension and by lowering the transmissioncosts by, for example, using Alloy conductors,which are also advantageous when spare systemsare installed or existing ACSR conductors arereplaced. Higher conductor tensions made possibledue to check measurements for vibration dangerlead to cost reductions when the line design isadapted correspondingly. The compact transmissionline with composite insulators is the obvioussolution to demands for lower visibility as well asfor the construction of new lines with higher operatingvoltage and transmission capacity on theroutes of older lines, as it has happened inSwitzerland. The obligation to achieve lower transmissioncosts tends to favour new lines with onlyone system and as well, the exploitation of costsavings possibilities in line- tower- and foundationdesign.In the past, improvements often used to beshunned because there seemed to be no economicnecessity for them. - Transmission line engineersshould be encouraged to abandon decadeoldstandard types of transmission line designs andinvestigate new solutions, taking account ofelectromechanical considerations and new workingmethods as well.The use of computers and relevant software hasmade it easier to follow this advice. The variousinvestigations described in the paper may givesome stimulus for that. Some of them are older andno longer up-to-date in their quantitative statementse.g. costs, but the tendencies demonstratedare still valid.While the experiences of other countries can be ofhelp, a closer intermeshing of electrical and structuralengineering investigations appears necessary.Furthermore, it is always worthwhile to studythe literature of transmission line technologythroughout the world, as this report shows.In any case, achieving a better relation betweensafety and economy requires improvements supportedby measurements, as well as real time monitoringto increase the capacity of the line, andvibration measurements (first 1954 in the USA,improved 1966 in Germany and 1975 inSwitzerland) to allow a decrease in the costs of theline by means of an increase in the conductor tension.The regulations should allow tests and measurementsas proof of safety to a greater degreethan has been achieved so far. By the same virtue,it should not be forgotten that in the past (first inItaly 1955), tower and foundation tests have oftenbeen carried out to verify theoretical calculations.