Comparación de esquemas de protección en redes de medio voltaje utilizando simulación en tiempo real

Abstract

This thesis develops and validates a protection scheme for a medium-voltage feeder, implemented in a simulation environment using Simulink modeling tools and MATLAB programming. The main objective is to analyze the coordination between two widely used protection functions in power systems: differential protection (87) and time-overcurrent protection (51). The algorithms were designed with MATLAB Function blocks that reproduce the behavior of a physical relay, considering current transformations, trip logic, state memory, and operating times. The 51 protection was configured with standardized curves following IEC 60255-151 and IEEE C37.112-1996, including inverse, very inverse, extremely inverse, and ultra-inverse families. Using these curves, the system performance was evaluated under three-phase and single-phase-to-ground faults, verifying trip sequence and selectivity between primary and backup protections. The simulation includes an equivalent model of a typical Ecuadorian distribution feeder, adjusted to real operating conditions. Measurement and monitoring tools were incorporated to record actual operating times and compare them with teoretical values derived from each curve. Results confirm that the system maintains proper time coordination, validating the logic of selectivity, sensitivity, and reliability. This work strengthens the technical analysis applied to distribution network protection and establishes a basis for future real-time implementations through Hardware-in-the-Loop testing or experiments with physical relays in laboratory environments, aligned with the ongoing transition toward digital substations and intelligent protection systems.