Voltage Relays – These relays operate on the principle of a set threshold deviation of either voltage drop or over voltage surge. Frequency Relays – Continuous surveillance of the system frequency is done, and relays that activate beyond set ranges provide safeguards. The Interactions of electromagnetic induction and mechanical switching comprise the working principle of a relay. An electromagnet, movable contacts, and a spring-loaded armature make up a relay. If an electric current is supplied to. What is the Main Function of Protection Relays? A voltage protection relay system is a necessary component of any electrical setup. It monitors voltage to determine if levels rise too high or dip too low. IEEE/IAS/I&CPSD Protection & Coordination WG Chair Jacobs Canada, Calgary, AB rasheek. com IEEE Southern Alberta Section PES/IAS Joint Chapter Technical Seminar - November 2016 Protective Relays - Technical Seminar Nov 2016 - Copyright: IEEE 2 Abstract: Protective relays and devices. Selectivity is a mandatory requirement for all protection, but the importance of it depends on the application. Currently residing in Denver, Colorado.