Integrated coordination and short circuit analysis for system protection

A coordinated set of data management and analysis programs, already in use at several major utilities in the USA, is presented. The programs are known as the computer-aided protection engineering (CAPE) system. CAPE consists of an integrated set of ten data management and analysis programs designed to assist protection engineers with their day-to-day activities of selecting, setting, and coordinating protective relays. Underlying all the CAPE programs is a comprehensive (and general-purpose) relational database of both system and protective service data. The practical of two of CAPE´s modules, Coordination Graphics and Short Circuit, for readily identifying and correcting miscoordinations is discussed. Both distance and overcurrent protective devices are treated. Realistic examples illustrate the detection of miscoordination. Corrective actions are taken using graphical manipulations (curve dragging) and direct specification of taps, test points, or desired reach