Disponibilidad inherente de los sistemas de protección y control en una bahía de línea de 500 kV: estudio de caso en Colombia

Introduction: The availability of protection and control systems in 500 kV transmission line bays is a key factor in ensuring operational continuity and the security of the National Transmission System. Objective: To evaluate the inherent availability of protection and control systems in a 500 kV transmission line bay arranged in a breaker-and-half configuration by comparing nominal reliability parameters provided by manufacturers with historical failure and repair data.Methodology: A series-parallel model based on Reliability Block Diagrams (RBDs) was developed in MATLAB to represent 13 Level 1 and Level 2 components of the protection and control system, including protective relays, bay controllers, and communication switches with LAN A/LAN B redundancy under IEC 61850. Nominal reliability parameters supplied by Siemens® and GE® were compared with a historical database equivalent to 287 devices operating over a 12-year period, with 81 recorded failures.Results: The total availability calculated using historical data from the protection and control systems of the transmission line under study was 99.8408%, compared with the manufacturer-estimated availability of 99.9977%. Conclusions: Catalog-based data significantly overestimate the actual performance of protection and control systems. Furthermore, real repair times are considerably higher than those assumed by manufacturers, highlighting the need to incorporate historical operating data into availability assessments, maintenance planning, and asset management strategies for extra-high-voltage substations.