ABB SPAJ140C-SPCJ-4D29 Protection Relay

The ABB SPAJ140C-SPCJ-4D29 Protection Relay is a compact, protection-focused device within ABB’s SPAJ 140 C series that provides combined overcurrent (OC) and earth-fault protection for medium-voltage feeders. The SPCJ 4D29 protection unit inside this module delivers phase overcurrent protection for single-phase, two-phase, or three-phase configurations and pairs it with earth-fault sensing for selective tripping in radial feeder applications. Designed for protection of feeders in solid-grounding, resistance-grounding, or impedance-grounding systems, this relay supports flush-mount installation in standard substation enclosures and can be integrated with ABB data communication units (for example SPA ZC family) to enable remote monitoring and control. The SPCJ 4D29 unit’s OC element is purpose-built for accurate current-based fault detection, while the earth-fault element provides reliable ground-fault indication, helping coordinate with breakers and other protective devices. The SPAJ 140 C/SPCJ 4D29 combination thus offers a single, configurable protection block for fast fault isolation and system reliability in medium-voltage networks.