Short-circuit effects in HV substations with strained conductors-systematic full scale tests and a simple calculation method

Abstract

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,

Optimization of short-circuit tests based on finite element analysis

“…The phase shift between current and voltage in the active loop has been calculated by comparing both voltage and currents acquisitions of the oscilloscope during the test. The apparent power has been calculated by applying (7), and the total active and reactive powers have been calculated by applying (10) and (11).…”

“…These contributions are based on the application of Maxwell's equations, Neumann's formula, and the Biot-Savart law. Moreover, many studies about the electrodynamics forces caused by short-circuit in bus-bars and conductors have been conducted [8] - [11]. However, no works dealing with the topic of this paper are found.…”

Estimation of Short Circuit Duration for the Assessment of Dynamic Effects in Distribution Substations with Flexible Conductors

“…Research centers around the world have already been interested in studying the phenomenon of electrodynamic interactions for short overhead spans in switching stations. Calculation of the dynamic effects in power distribution substations with flexible conductors has been discussed by many authors [1][2][3][4][5][6][7]. In the nineties, the issue was also addressed by CIGRÉ.…”

Tests and calculations of short‐circuit forces and displacements in high‐voltage substations with strained conductors and droppers

“…2 have conducted experimental study [l] and the present one, the previous study I23 having formed the basis for the introduction of the calculation procedure for the so-called 'long spans' of stranded conductors. In spite of this time-and cost-consuming, but necessary, reservation, quite a satisfactory number of rigid as well as stranded conductor arrangements have been made accessible to standardized calculation procedures for short-circuit stresses and strength.…”