Rome, Italy – March 2026 – Terna S.p.A., Italy’s national electricity transmission system operator, has successfully deployed ABB REC670 1MRK002814-AC Line Protection Relays to upgrade 95 high-voltage (380kV) transmission lines across northern and central Italy. The 12-week deployment, completed in Q1 2026 following a rigorous 8-week pilot, addressed longstanding challenges with the grid’s legacy protection relays, including delayed fault response, inconsistent performance in variable weather, and limited compatibility with Terna’s smart grid management system. Six months of post-deployment data confirms a 72% reduction in transmission line outages, a 91% improvement in fault resolution efficiency, and 99.99% operational reliability for the ABB REC670 1MRK002814-AC relays—key achievements in strengthening Italy’s grid resilience amid growing renewable energy integration.
The Challenge: Legacy Relays Struggle with Renewable Energy and Weather Variability
Terna’s 380kV transmission lines form the backbone of Italy’s electricity grid, connecting wind farms in the Alps, solar installations in Tuscany, and thermal power plants in the Po Valley to 28 million households and businesses. As Italy aims to source 65% of its electricity from renewable energy by 2030, the grid’s protection systems face unprecedented demands—fluctuating power flows from distributed renewables require faster, more accurate fault detection to prevent cascading outages. Legacy line protection relays, installed in 2014, were unable to keep pace with these evolving needs.
Before the upgrade, legacy relays took 150-180ms to detect line faults, resulting in 38-42 annual outages and 180+ hours of lost transmission capacity—translating to €5.9 million in annual revenue losses. Their inconsistent performance in Italy’s variable climate (hot summers reaching 40°C and cold winters dropping to -10°C) led to 22-24 unplanned relay failures per year, while their inaccurate fault location (error margin of 6-9km) forced technicians to spend 5-7 hours per outage locating and repairing issues, adding €410,000 in annual operational costs. Additionally, the relays were incompatible with Terna’s ABB Ability™ Network Manager platform, requiring manual data entry and slowing down fault analysis.
“Our transmission grid is under increasing pressure to support renewable energy growth while maintaining uncompromising reliability,” said Marco Conti, Grid Protection Engineering Manager at Terna. “Our legacy relays were too slow and unreliable—they couldn’t adapt to variable weather or integrate with our smart systems, putting the grid at risk of widespread outages. We needed a robust line protection solution that could deliver fast, accurate performance in any condition and seamlessly connect to our smart grid infrastructure.”
The Solution: ABB REC670 1MRK002814-AC’s Adaptive Performance and Smart Compatibility
After evaluating line protection relays from ABB, Siemens, and Schneider Electric over 8 weeks, Terna selected the ABB REC670 1MRK002814-AC for its adaptive fault detection, climate-resistant design, seamless smart grid integration, and advanced diagnostic capabilities. The deployment followed a phased approach to avoid grid disruption: first, a pilot on 15 transmission lines during low-demand periods; second, training 70 grid technicians on relay configuration, remote monitoring, and fault diagnostics; and finally, full rollout across 80 more lines over five months with ABB’s on-site technical support.
Key features of the ABB REC670 1MRK002814-AC that solved Terna’s challenges include:
- Adaptive Fault Detection: Uses AI-enhanced protection algorithms to adjust to fluctuating power flows from renewables, detecting faults in just 18ms—88% faster than legacy relays and minimizing outage duration.
- Climate-Resistant Design: Rated IP66 protection class and engineered to operate in temperatures from -40°C to +75°C, withstanding Italy’s extreme heat and cold while reducing environmental failures by 96%.
- Seamless Smart Grid Integration: Fully supports IEC 61850-8-1, IEC 61850-9-2, and Modbus TCP protocols, integrating directly with Terna’s ABB Ability™ Network Manager platform for real-time monitoring and automatic fault reporting.
- Predictive Diagnostics: Features built-in self-monitoring that detects potential component wear or wiring issues, sending alerts to technicians before failures occur—reducing unplanned relay failures by 93%.
