INTEGRATED COORDINATION AND SHORT-CIRCUIT ANALYSIS FOR SYSTEM PROTECTION

The operational demands placed on modern power transmission networks as well as their topological complexity make the task of the system protection engineer ever more difficult. The need for computer-based tools to assist with the evaluation and possible correction of relay settings is therefore more immediate. A coordinated set of data management and analysis programs, already in use at several major utilities in the USA, is presented. The primary focus here is on the so-called Coordination Graphics module. 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.