Automated protection grading and performance analysis system

It is generally accepted that the selection and setting of protective relays is a tedius, repetitive and time consuming task performed by the protection engineer relatively infrequently. The specification and assessment of computer aided design tools for use in the protection engineering field has provided the opportunity of relieving the protection engineer from the routine calculations, thus allowing valuable time to be spent considering more technical and engineering design problems which may occur. Here, the authors develop a protection grading software package to provide calculation of network fault conditions and, using this information, to enable protection relay settings and clearance times to be determined as a first pass, prior to allowing user interaction to produce final customised settings. By using the developed CAD approach in a novel integrated environment operating from customised Microsoft Windows software, the engineer can control the solution process by exercising options at intermediate stages, thus allowing the engineers to use their knowledge and judgement in guiding the solution process