Ireland SPaj140C Relay Protection Device

The ABB SPAJ140C is a combined overcurrent and earth-fault relay designed for rapid, multi-stage protection of feeders and motors in industrial and utility power systems.OverviewThe SPAJ140C is a high-performance numerical protection relay that integrates phase overcurrent and neutral earth-fault detection into a single compact unit, suitable for radial feeders in solidly-earthed, resistance-earthed, or impedance-earthed systems (ABB) . It provides selective short-circuit and earth-fault protection, ensuring rapid isolation of faults to safeguard equipment and maintain system stability.Key FeaturesMulti-stage protection: Low-set and high-set stages for sustained overloads and severe short circuits, with fault isolation in as little as 40 ms .IDMT and definite-time curves: Six IDMT curve options allow precise coordination with upstream and downstream devices .Circuit breaker failure protection: Built-in functionality to detect and respond to breaker malfunctions .Flexible tripping and signaling: Supports alarms, auto-reclosing, and fault data recording .Output relays: Two heavy-duty and four light-duty relays configurable for various applications .Communication and configuration: Settings can be adjusted via front panel push buttons, serial communication bus, PC software, or external control signals .OperationThe SPAJ140C continuously monitors phase currents and neutral current through connected current transformers. When a fault exceeds the programmed thresholds:The relay issues a start signal for the overcurrent or earth-fault unit.After the preset operate time, it trips the circuit breaker.It can initiate auto-reclosing, provide alarms, and record fault data for analysis . The low-set stages handle sustained overloads, while high-set stages respond to severe short circuits, ensuring dual-layer protection .Technical SpecificationsOperating voltage: 18–265 V AC/DC depending on model .Frequency range: 50–60 Hz .Current settings: Configurable for single, two, or three-phase overcurrent protection .Self-supervision: Continuous hardware and software diagnostics with internal fault indicators .Display: Numerical display for settings, measured values, fault codes, and memorized fault data .ApplicationsThe SPAJ140C is suitable for:Industrial networks: Protecting motors, feeders, and distribution lines.Utility networks: Ensuring selective protection in medium-voltage systems.Radial feeders: In solidly, resistance, or impedance-earthed systems .Maintenance and SupportFault indications: Internal relay faults are indicated via the IRF indicator and diagnostic codes .Resetting: Indicators can be reset via the front panel or external control input .Software support: PC-based tools allow parameter recording, configuration, and monitoring . The SPAJ140C combines robust protection, flexible configuration, and rapid fault response, making it a reliable solution for industrial and utility power system protection in Ireland and globally.