THE RELAY TESTING HANDBOOK #3: Understanding Digital Logic

This edition of The Relay Testing Handbook series explains the different forms of relay logic used in modern microprocessor based relays. Each type of relay logic is described in detail with many examples to show that all relay logic uses the same essential components with different man-machine interfaces. This publication allows the reader to understand logic and convert relay settings using one system into the logic of another system using examples. The reader will be able to understand the protective relay logic in nearly every in-service relay today after applying the principals of this chapter.* Understanding Logic - OR - AND - NOT - NOR - NAND - Comparator - Timer* Relay Labels and Word Bits* Internal Relay Logic - GE/Multilin* Binary Relay Logic - GE Alstom/Alstom* Arithmetic (Math) Scheme Logic - SEL* FlexLogicTM - GE