These methods include comparing sequence components (V0 vs. I2), and cross polarization methods utilizing VBC for IAG and IAB faults as well as traveling wave relationships. Examples will be presented showing polarization methods for different system. Selective short-circuit protection can be achieved in different ways, such as: Time-graded protection Time- and current-graded protection A straightforward way of obtaining selective protection is to use time grading. The principle is to grade the operating times of the relays in such a way that. Protective Relays - Technical Seminar Nov 2016 - Copyright: IEEE 2 Abstract: Protective relays and devices have been developed over 100 years ago to provide “lastline”of defense for the electrical systems. Directional relays play a crucial role in the protection and control of power systems, ensuring the reliable and efficient operation of electrical networks. Types of Protective Relays: Protective relays are categorized by their mechanism (electromagnetic, static, mechanical) and function. In electrical engineering, a protective relay is a relay device designed to trip a circuit breaker when a fault is detected.