Upgrading Argentina's 500 kV Transmission Network: From Legacy SDH Microwave to Hybrid TDM/Packet Systems for Enhanced Reliability

Transmission Mode 1 (STM-1) level, ensuring a consistent network. After 25 years, the optical backbone was replaced with Multiple Protocol Label Switching – Transport Profile (MPLS-TP) technology, but the SDH microwave radios and multiplexers remained in service linking those remote nodes. A new project now replaces this legacy equipment with a Hybrid Microwave

System spanning 230 km in Argentina’s Patagonia, introducing split-architecture radios and

MPLS-TP switches. Migration requires coexistence of old and new systems to guarantee uninterrupted operation of critical services.

The transition moves applications from circuit-switched Time Division Multiplexing (TDM) to

Packet-Switched networks (PSN). Mission Critical Functions include line differential and impedance protections, telephony, SCADA, synchrophasor data, remote Intelligent Electronic

Device (IED) access, and automatic generation disconnection. Non-Critical Functions, such as access control, intrusion detection, video surveillance, transformer monitoring, and management facilities, enhance reliability and efficiency. The guiding principle is extremely low failure rates, with robust Operational Technology (OT) cybersecurity policies integrated into design and implementation. Key goals are reducing outages, extending infrastructure life, minimizing vulnerabilities, preventing catastrophic failures, and enabling easier monitoring through modern management systems.

Beyond transmission, the industry is shifting toward asset management models driven by data.

New services include predictive maintenance, augmented reality remote assistance, equipment monitoring, diagnostic systems, intelligent inspections via drones and sensors, and mobile field applications. These require high-volume data handling alongside deterministic mission-critical traffic. MPLS-TP was selected as the unifying multiplexing technology, adaptable across fibre and microwave. Radio systems must be carefully designed to transport MPLS-TP frames, balancing determinism with bandwidth. Four radio variants—TDM, hybrid, packet, and hybrid+packet—offer different coexistence strategies, with hybrid solutions ensuring mission-critical reliability while supporting modern data demands.