Transmission lines are a vital part of the electrical distribution system, as they provide the path to transfer power between generation and load. Transmission lines operate at voltage levels from 69kV to 765kV and are ideally tightly interconnected for reliable operation.
Factors like de-regulated market environment, economics, right-of-way clearance, and environmental requirements have pushed utilities to operate transmission lines close to their limits. Any fault, if not detected and isolated quickly will cascade into a system-wide disturbance causing widespread outages for a tightly interconnected system operating close to its limits.
Transmission protection systems are designed to identify the location of faults and isolate only the faulted section. The key challenge to transmission line protection lies in reliably detecting and isolating faults compromising the security of the system.
