ABB SPAJ140｜Earth Fault Relay｜

SPAJ140

The ABB SPAJ 140 C is a digital, microprocessor-based 3-phase overcurrent and earth-fault protection relay from the SPACOM product line. Designed for selective protection in electrical distribution networks, it safeguards feeders, power transformers, and AC drives against overcurrent, short-circuit, and ground-fault conditions.
Internal Module Architecture

The relay assembly houses a single combined protection and control module:

SPCJ 4D29: The core sub-module handling signal sampling, IDMT timing calculations, trip logic, and user display functions.

Key Differences: SPAJ 140 C vs. SPAJ 110 C

While both relays belong to the SPACOM feeder protection series, the SPAJ 140 C introduces enhanced flexibility and control logic over the basic SPAJ 110 C:

Circuit Breaker Failure Protection (CBFP): Includes built-in CBFP logic to initiate backup tripping if the primary breaker fails to open.

Expanded Output Relays: Features additional configurable matrix output contacts (typically 4 signaling + 2 trip outputs vs. fewer options on the 110 C).

Flexible Input Routing: Incorporates additional opto-isolated binary inputs for external tripping, interlocking, or remote reset.

Core Protection Functions

Phase Overcurrent Protection ($I> / I>>$)

Low-set stage ($I>$): Configurable for Inverse Definite Minimum Time (IDMT) or definite-time operation. Supports IEC 60255 curves (Normal, Very, Extremely, Long-Time Inverse).

High-set stage ($I>>$): Instantaneous or definite-time tripping with optional latching/lockout functionality.

Earth-Fault Protection ($I_0> / I_0>>$)

Low-set stage ($I_0>$): Non-directional ground-fault protection using definite-time or IDMT characteristics.

High-set stage ($I_0>>$): High-speed instantaneous or definite-time trip logic for severe ground faults.

Technical Specifications
Specification Parameter / Value
Rated Current ($I_n$) $1\text{ A}$ or $5\text{ A}$ (selectable via CT wiring terminals)
Rated Frequency ($f_n$) $50\text{ Hz}$ or $60\text{ Hz}$
Auxiliary Voltage ($U_{aux}$)

• SPAJ 140 C1: $80\text{–}265\text{ V AC/DC}$

• SPAJ 140 C2: $18\text{–}80\text{ V DC}$Output Contacts 2 Heavy-duty trip relays, 4 signal/alarm relays, 1 Internal Relay Fault (IRF) system alert
Binary Inputs Opto-isolated inputs for external trip command, blocking, or fault reset
Serial Bus Interface SPA-bus protocol over rear optical fiber (ST connectors) or RS-485 interfaces
Modern Replacement