The Delgado Bible

Delgado Relay Protection Reference is an independent engineering resource offering browser-based tools, learning modules, and technical notes for relay protection professionals. Built and maintained by Cesar Delgado, who has more than 30 years of experience in substation automation and relay protection engineering, the platform draws on practical engineering workflows to help users explore, verify, and explain protection concepts.

Its interactive tools support IEC 61850 SCL file analysis, including diagnostics and single-line, IED, GOOSE, and sampled-value views. Engineers can also review COMTRADE fault records, inspect synchronized waveforms and event timing, visualize voltage and current phasors and impedance, calculate fault behavior, and create time-current curves for coordination studies. A directional overcurrent tool helps users examine trip regions and relay logic.

Designed for protection and system engineers, utilities, industrial teams, EPC and consultancy groups, commissioning professionals, students, and trainers, the site connects technical explanations with hands-on analysis. Tools run in the browser, and SCL files are processed locally.