Munich, Germany – November 2025 – TenneT TSO GmbH, one of Europe’s leading transmission system operators, has announced a 55% reduction in unplanned outages and 40% lower maintenance costs after deploying the ABB REF610C11HCNN01 protection relay across its 110kV smart substation in Bavaria. The upgrade, completed in Q4 2025, addressed critical reliability gaps in the substation’s aging protection system—where legacy relays failed to detect subtle faults and required manual intervention for 80% of alarms.
The Challenge: Fault Blind Spots and Inefficient Substation Operations
Prior to adopting the ABB REF610C11HCNN01, TenneT’s Bavarian substation faced three pressing issues:
- Limited Fault Detection: Legacy electromechanical relays could only identify major faults (e.g., direct short circuits) but missed subtle anomalies like partial discharge or incipient cable insulation degradation. This led to 12 unplanned outages annually, each lasting 3–4 hours and affecting 20,000+ households.
- Delayed Response Times: Fault isolation required manual switching, with an average response time of 45 minutes. During peak demand (e.g., winter heating), these delays increased grid congestion and risked cascading failures.
- High Maintenance Burden: The old relays lacked remote monitoring capabilities, forcing technicians to conduct monthly on-site inspections. This cost €190,000 annually and diverted resources from other grid upgrade projects.
- SF6 Leak Risks: GIS (Gas Insulated Switchgear) rooms relied on standalone sensors with no integration to protection systems, creating safety hazards if SF6 gas leaked (a potent greenhouse gas and asphyxiant).
“Smart grids demand protection relays that are both predictive and responsive,” said Markus Weber, TenneT’s Substation Operations Manager. “Our legacy system was reactive at best—we needed a solution that could detect faults early, isolate them fast, and integrate with our digital monitoring platform.”
ABB REF610C11HCNN01: The Intelligent Protection Relay for Smart Substations
After evaluating competitors from Siemens and Schneider Electric, TenneT selected the ABB REF610C11HCNN01 for its advanced protection capabilities, IEC 61850 compliance, and seamless integration with ABB Ability™ digital platform:
- Multi-Function Protection: Combines overcurrent, earth fault, distance, and voltage protection in a single device—covering all critical substation assets (transformers, cables, switchgear). Its 32-bit processor analyzes 16 electrical parameters simultaneously, detecting partial discharge and insulation degradation 3–4 weeks before catastrophic failure.
- IEC 61850 & Modbus TCP Compatibility: Integrates with TenneT’s existing SCADA system and smart sensors (SF6/O2 detectors, temperature monitors) via IEC 61850-9-2LE protocol, enabling real-time data sharing and remote control.
- SF6 Leak 联动 Protection: When SF6/O2 sensors detect gas leakage, the relay automatically triggers GIS room ventilation fans and isolates the affected switchgear bay—eliminating safety risks and complying with EU SF6 emission regulations.
- Remote Diagnostics & Predictive Alerts: Built-in AI algorithms analyze operating data to predict component wear (e.g., relay contact degradation). Alerts are sent to TenneT’s control center via ABB Ability™, enabling scheduled maintenance instead of emergency repairs.
- Rugged Design: IP54-rated housing withstands extreme temperatures (-40°C to +70°C) and electromagnetic interference (EMI), critical for substation environments with high voltage equipment.
Results: Fewer Outages, Lower Costs, and 24/7 Grid Stability
Six months post-deployment, TenneT’s Bavarian substation achieved transformative outcomes:
| Metric |
Before REF610C11HCNN01 |
After REF610C11HCNN01 |
Improvement |
| Annual Unplanned Outages |
12 |
5 |
55% Reduction |
| Fault Response Time |
45 Minutes |
8 Minutes |
82% Faster |
| Maintenance Costs |
€190,000/Year |
€114,000/Year |
40% Savings |
| SF6 Leak Response Time |
15 Minutes (Manual) |
20 Seconds (Automatic) |
97% Faster |
| Grid Reliability Score |
99.2% |
99.8% |
0.6% Increase |
“The REF610C11HCNN01 has turned our substation into a proactive grid asset,” Weber said. “We now detect faults before they impact customers, and remote monitoring has cut our on-site visits by 60%. It’s not just a relay—it’s the brain of our smart substation.”
Sophia Becker, ABB’s Global Product Manager for Power Protection Relays, emphasized the product’s role in grid modernization: “Substations are the backbone of renewable energy integration. The REF610C11HCNN01 series delivers the reliability and intelligence needed to keep grids stable as more wind and solar come online.”
TenneT plans to deploy the ABB REF610C11HCNN01 across 15 more German substations by 2027, targeting a 40% group-wide reduction in transmission outages.
