The dynamic short-circuit stresses in HV substations with flexible conductors are determined by a large number of parameters. Their influence has been studied in seven test arrangements representing strained conductors of typical 123 kV and 420 kV substations by systematically varying the parameters. The test results obtained show that i t is possible to use the simple method of IEC hbl. 865 together with proposed additions for the calculation of short-circuit effects in strained conductors of long span length. 1 N T R o m 1 0 N The forthcoming Cigrd brochure MechaniurL Effects of Short-Circuit Currents in Open Air Wstations Cl] prepared by Working Group 2 High Short-circuit Currents of Study Comnittee 23 &&stattons in coordination with Technical Comnittee 73 Short-Circuit Currents of the IEC distinguishes three classes of calculation methods simple, medium and advancedf o r the analysis of substation busbar systems with flexible, i.e. stranded conductors. Order and nomenclature do not imply anything about the quality of results in terms of precision.Advanced methods are based on a finite element analysis, medium methods are computer methods that employ certain simplifications and approximations reducing problem complexity. Simple methods, in terms of application, are those given in the international and national standards C2.31. They represent a condensation of calculations employing higher order methods and a great deal of test experience over the defined range of application, giving the user a direct analytical and simple access to the essential solutions, i.e. the maxima to be considered. Apart from their application advantages, the simple methods are all the more important for laying down accepted forms of calculation and limits of loading and thus represent quasilegal rules for correct and safe design. All the methods have in c o n " that a grid of test results is indispensable for their development, for proof of validity and competent application.Until some ten years ago experience indicated no general need to consider "long spans" of conductorsi.e. suspensions between steel structures of roughly 25 m and morefor short-circuit strength. The usual static load assumptions covered the short-circuit case and individual exceptions did not require a standardized procedure. Rising short-circuit levels changed the situation. The 1982 edition of the German standard DIN VDE 0103 announced investigations on such constructions and the IFC Publication 865 of 1986 formulated the 88 SM 709-8 by the LEEE Substations Committee of the IEEE Power Engineering Society €or presentation at the IEEE/PES 1988 Summer Meeting,
Energy consumption, greenhouse gas emissions, environmental impact levels, and the availability of materials as well as their sustainable usage are all topics of high current interest. The energy intensive processes of casting production such as heat treatment are particularly affected by the pursuit of sustainability. It has been estimated that up to 20% of the total energy demand in a non-ferrous foundry is required to provide the heat energy necessary during heat treatment processes. This paper addresses the application-oriented development of a sustainable configuration of the heat treatment process at the example of the aluminium-casting alloy A356 (AlSi7Mg0.3). Based on calculations of the physically necessary operating modes and under investigation of previous parameter recommendations, experimental studies were carried out to investigate the effects of various heat treatment parameters on the ultimate mechanical properties of the alloy. Since the achievable mechanical properties of the finished casting are decisive, the static and dynamic casting properties resulting from the heat treatment with optimized process parameters were compared with those of conventional process control. Significant optimization potential is shown for reducing the treatment time and thus lowering the energy consumption.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.