Wide-Area Protection System Studies

As part of their day-to-day activities, protection engineers use short-circuit programs and associated relay setting tools to calculate settings for relays that are applied on primary equipment like transmission lines, transformers, distribution feeders and generators. Once these settings are calculated, the engineer has to test whether the settings applied to the relays operate reliably when required, and ensure coordination with settings on other relays in the vicinity. The terms "sensitivity" and "selectivity" are often used to describe these functional requirements.