ASSESSMENT OF THE DYNAMIC PERFORMANCE OF FLEXIBLE BUSBAR SYSTEMS UNDER VARYING FAULT CONDITIONS

摘要

This paper looks at fault conditions in substation systems relating both a dynamic assessment approach to the loading imparted on supporting structures and theoretical conditions presently considered when evaluating asset fault capacity. Established power networks are commonly facing the need for sound asset management and clear prioritising of maintenance, strengthening or replacement. This includes substation support structures which can vary in form and material composition as well as age and condition. One of the more complex problems that needs to be addressed is that of structural capacity assessment, particularly where there is an alteration in service needs and existing support infrastructure has been designed to redundant standards and for different service conditions. Present international standards include the calculation of equivalent static loads for the assessment of structures under short circuit loading. This approach does not is more onerous than the true transitory loads imparted by the motion of flexible bus-bars following a short circuit fault of, typically, less than 1 second. Additionally, worst case conditions are built into assessment criteria defined in some standards, which can combine to provide over-conservative results. In this work the structures response to short circuit electromagnetic impulses have been modelled dynamically using a multi-physics dynamic finite element analysis program. Results have been verified against CIGRE published test results and cases compared against calculated values produced by established codified methods. Significant gains in asset sustainability are shown to be apparent by the introduction of dynamic analysis techniques. With an aging asset stock the potential usefulness of this approach is the creation of a broader range of options when operators are faced with changes in service conditions.