Madrid, Spain – November 2025 – Madrid’s municipal power utility, Madrid Distribución Eléctrica (MDE), has announced a transformative 62% reduction in unplanned power outages across its 10kV urban distribution network, following the deployment of ABB’s SPAJ140C highly integrated protection relays. The 18-month upgrade project, completed in Q3 2025, replaced 380 outdated electromechanical relays with the SPAJ140C series, addressing critical reliability gaps in the city’s aging power infrastructure while supporting Spain’s 2030 carbon neutrality goals.
The Urban Grid Challenge: Outdated Relays Hinder Reliability
Prior to the upgrade, MDE’s distribution network relied on 25-year-old electromagnetic relays that struggled to meet modern urban power demands. Key pain points included:
- Slow Fault Response: Traditional relays took 2–3 seconds to detect and isolate single-phase earth faults, leading to widespread outages affecting 5,000+ residents per incident.
- Frequent False Trips: Poor electromagnetic compatibility (EMC) caused 12–15 false trips monthly, disrupting businesses and critical services like hospitals and transit systems.
- Limited Visibility: Lack of digital monitoring made fault localization time-consuming—technicians required 4–6 hours to identify and repair underground cable faults.
- Maintenance Headaches: Obsolete components meant replacement parts were scarce, increasing maintenance costs by €450,000 annually.
“Madrid’s population growth and rising electric vehicle adoption strained our legacy grid,” explained Carlos Ruiz, MDE’s Grid Modernization Director. “We needed an integrated protection solution that could handle complex fault scenarios, reduce downtime, and integrate with our smart grid platform—all while withstanding the electromagnetic interference from urban infrastructure.”
ABB SPAJ140C: The Integrated Protection Solution for Smart Cities
After evaluating three competing relays, MDE selected the ABB SPAJ140C for its unique combination of integration, reliability, and smart grid compatibility:
- Dual Protection Modes: The SPAJ140C’s integrated overcurrent and earth fault protection delivers selective tripping via inverse definite minimum time (IDMT) or definite time characteristics. Its high-set overcurrent unit triggers instantaneous trips (40ms response) for severe short circuits, while low-set units prevent overload damage with adjustable time curves .
- EMC-Certified Durability: Compliant with IEC 61850 standards and EU CE certification, the relay’s shielded housing and filtering circuits resist interference from nearby motors, EV charging stations, and telecom equipment—eliminating false trips .
- Smart Fault Localization: Built-in 零序电流（zero-sequence current）monitoring pinpoints single-phase earth faults within 500 meters, cutting fault-finding time from hours to minutes .
- Seamless Integration: The relay’s serial communication port and SPA-ZC bus module connect to MDE’s existing SCADA system, enabling real-time remote monitoring, parameter adjustment, and event logging .
- Hot-Swappable Design: Modular construction allows technicians to replace faulty units in 30 minutes without shutting down entire feeders, minimizing service disruption .
Deployment & Measurable Results
MDE’s implementation team installed 380 SPAJ140C relays across 120 residential neighborhoods and 15 industrial zones, prioritizing high-fault areas. The project included on-site training for 60 technicians, focusing on relay configuration and remote diagnostics via ABB’s software tools.
Six months post-deployment, the results are transformative:
- Outage Reduction: Unplanned outages dropped from 2.8 per month to 1.0, with average downtime per incident falling from 92 minutes to 35 minutes—a 62% improvement.
- False Trips Eliminated: Monthly false trips decreased from 14 to 0, saving MDE €180,000 in customer compensation and service restoration costs.
- Maintenance Efficiency: Fault localization time reduced by 85%, cutting annual maintenance costs by €290,000.
- Grid Resilience: The relay’s circuit-breaker failure protection logic prevented 3 potential cascading outages during extreme weather events in September 2025 .
“The SPAJ140C isn’t just a replacement relay—it’s the brain of our smart grid,” Ruiz stated. “We can now isolate faults to a single city block instead of an entire district, keeping power flowing to homes and businesses while our teams resolve issues.”
Elena Martinez, ABB’s EMEA Product Manager for Distribution Protection, emphasized the relay’s alignment with urban electrification trends: “Cities need integrated protection that balances speed, accuracy, and connectivity. The SPAJ140C’s dual protection functions and smart monitoring capabilities make it ideal for modernizing aging grids while supporting renewable energy integration.”
MDE plans to expand the SPAJ140C deployment to its remaining 80 distribution zones by 2026, with a goal of achieving 99.98% grid reliability—among the highest in Europe.
