Reliable busbar protection with advanced zone selection

Modern digital relays use innovative algorithms to fulfill busbar protection requirements of fast operating times for all busbar faults, security for external faults with heavy current-transformer (CT) saturation, and minimum delay for evolving faults. This paper describes a reliable protection system that includes busbar protection and advanced zone selection; the protection system is suitable for the protection of multiple busbar arrangements. The protection system consists of several protection principles and measuring techniques using instantaneous and phasor quantities in a unique combination to achieve reliable busbar protection with minimum CT performance requirements.