PROT 401 provides an overview of the principles and schemes for protecting power lines, transformers, buses, generators, and motors. The report will identify methodology behind these practices, present issues raised by the integration of microprocessor relays and the internal logic and external communication configurations, ying. Product Specialist (West Region) for Digital Substation Products at ABB Inc. Currently residing in Denver, Colorado. This handbook covers the code of practice in protection circuitry including standard lead and device numbers, mode of connections at terminal strips, colour codes in multicore cables, dos and donts in execution. Types of Protective Relays: Protective relays are categorized by their mechanism (electromagnetic, static, mechanical) and function. Recognized under 2(f) and 12 (B) of UGC ACT 1956 (Affiliated to JNTUH, Hyderabad, Approved by AICTE - Accredited by NBA & NAAC – 'A' Grade - ISO 9001:2015 Certified) Maisammaguda, Dhulapally (Post Via. Kompally), Secunderabad – 500100, Telangana State, India To introduce all kinds of circuit. Protective relays and devices have been developed over 100 years ago to provide “lastline”of defense for the electrical systems. The selection and applications of.