The “protection zone” in an electrical power system is defined as the specific region within the system that is monitored and protected from faults by protective relays. This zone is established around each major piece of equipment within the power system. Licensed professional engineer for 15 years. 25 years in the electrical industry including 10 years as a MEP consulting engineer. SEL time-domain technology. Power System Protective Relays: Principles & Practices Protective Relays - Technical Seminar Nov 2016 - Copyright: IEEE 1 Power System Protective Relays: Principles & Practices Presenter: Rasheek Rifaat, P. For example, unselective protection operation during a medium voltage network fault will cause an outage for an unnecessarily large number of consumers. : 4 The first protective relays were electromagnetic devices, relying on coils operating on moving parts to provide detection of abnormal operating conditions such as. Eaton's protective relays provide you with unique microprocessor-based devices that eliminate unnecessary trips, mitigate arc faults, protect motors and breakers, and provide system information to help you better manage your system.