ABB SPAJ Series Relays

Technical Dossier

Product Details And Specifications

ABB SPAJ Series: Comprehensive Module Range and Technical Overview

The ABB SPAJ series represents one of the most widely deployed families of numerical protection relays in global heavy industry. Installed across chemical processing plants, nuclear power auxiliary systems, oil refineries, pulp and paper mills, and offshore platforms, the SPAJ range provides overcurrent and earth-fault protection for medium-voltage feeders, motors, and transformers. Its modular architecture, DIN-rail and flush-panel mounting compatibility, and standardized COMBIFLEX wiring system made it the default protection relay specification for utilities and industrial EPC contractors throughout the 1990s and 2000s. The series remains active in tens of thousands of switchgear panels globally, making long-term spare parts availability a critical operational requirement for asset owners.

The Evolution of SPAJ Series Architecture

The SPAJ series was introduced by ABB (then ABB Strömberg, Finland) in the late 1980s as part of the broader SPAM/SPAJ/SPCJ numerical relay platform. Early variants such as the SPAJ 140 C used analog input processing with digital logic, operating on a 24–240 V DC/AC auxiliary supply range. The architecture centered on a self-contained relay module with integrated measurement, protection logic, and output relay functions — eliminating the need for separate measuring units common in electromechanical designs.

Through the 1990s, ABB expanded the SPAJ range to cover directional overcurrent (SPAJ 142 C), combined overcurrent and earth-fault with auto-reclose (SPAJ 144 C), and motor protection variants. Communication capability was added via the SPA-bus (ABB's proprietary serial protocol) using the SPAC 531 C communication module, enabling integration with early SCADA systems. By the mid-2000s, the SPAJ platform was progressively superseded by the REF 541/542/543/545 series (IEC 61850-capable), and later by the REF630 series under the Relion® platform. However, the installed base of SPAJ relays in legacy switchgear panels means that SPAJ140C-AA and related variants remain in active service and require ongoing spare parts support through at least 2035 under typical 30-year asset lifecycle assumptions.

Compatibility note: SPAJ relays use the COMBIFLEX plug-in system. Replacement units must match the original case size (standard or high) and terminal block configuration. Firmware versions affect setting ranges — always verify relay version against the original protection coordination study before replacement.

SPAJ Series Full Catalog & Functionalities (SKU List)

Overcurrent & Earth-Fault Protection Relays

• SPAJ 140 C: Three-phase overcurrent and single earth-fault relay, non-directional, IDMT/definite time characteristics.
• SPAJ 140C-AA: Variant of SPAJ 140 C with specific auxiliary voltage range (24–240 V AC/DC); standard production designation for most markets.
• SPAJ 141 C: Overcurrent relay with high-set instantaneous element and extended setting range for feeder protection.
• SPAJ 142 C: Directional overcurrent and earth-fault relay; includes voltage input for directional element; used in ring-main and meshed network feeders.
• SPAJ 143 C: Combined overcurrent, earth-fault, and negative-sequence (unbalance) protection; motor and generator feeder applications.
• SPAJ 144 C: Overcurrent and earth-fault relay with integrated single-shot auto-reclose function; overhead line feeder protection.
• SPAJ 145 C: Overcurrent relay with thermal overload model; designed for cable feeder and transformer protection.
• SPAJ 160 C: High-impedance restricted earth-fault relay; transformer and generator stator protection.
• SPAJ 3C3: Three-phase overcurrent relay with three independent IDMT elements; used in multi-feeder protection schemes.
• SPAJ 4C4: Four-element overcurrent relay; applied in bus coupler and incomer protection.

Motor Protection Relays

• SPAM 150 C: Motor protection relay with thermal model, locked rotor, and unbalance protection; direct SPAJ platform derivative.
• SPAM 151 C: Extended motor protection with RTD input capability for stator winding temperature monitoring.

Communication & Auxiliary Modules

• SPAC 531 C: SPA-bus communication module; retrofits to SPAJ relay front panel; enables remote setting and event reading via RS-485.
• SPAC 532 C: Enhanced communication module with additional I/O; used in substation automation integration projects.
• SPTO 1D3: Output relay extension module; adds additional trip and alarm contacts to SPAJ base relay.
• SPTO 1D5: Five-output relay extension; used where multiple trip circuits or signaling outputs are required.
• SPTE 1E3: Power supply and I/O module; provides regulated DC supply and binary input expansion for SPAJ systems.

Sourcing Hard-to-Find & Obsolete SPAJ Series Parts

ABB formally discontinued active production of the SPAJ 140 C and most SPAJ-series variants in the early 2010s, transitioning customers to the REF630 Relion® platform. However, the discontinuation of new production does not eliminate the installed base requirement. Switchgear panels built around SPAJ relays cannot be upgraded to REF630 without full panel redesign, re-wiring, and re-commissioning — a capital expenditure that most asset owners defer for 10–20 years post-discontinuation.

DriveKNMS maintains a dedicated inventory of SPAJ series relays sourced from decommissioned switchgear, authorized surplus channels, and factory-sealed old stock. All units are cataloged by part number, hardware revision, and auxiliary voltage variant. For the SPAJ140C-AA specifically, DriveKNMS holds stock across multiple hardware revisions and can cross-reference against the customer's existing panel documentation to confirm compatibility before shipment.

Quality Control for the SPAJ Series Range

SPAJ series relays present specific testing challenges due to their COMBIFLEX plug-in architecture and SPA-bus communication interface. DriveKNMS applies the following test protocol to all SPAJ units prior to dispatch:

• Auxiliary supply verification: Unit powered at rated auxiliary voltage (24 V, 48 V, 110 V, or 220 V DC/AC as applicable); inrush current and steady-state consumption measured against factory specification.
• Current input calibration: Secondary injection testing using a relay test set (Omicron CMC or equivalent); pickup current, time-current characteristic (IEC/IEEE curve selection), and high-set instantaneous element verified at ±2% tolerance.
• Earth-fault element test: Sensitive earth-fault input tested at low-current injection levels (typically 10–100 mA range) to verify correct operation of the Io element.
• Output relay contact resistance: All trip and alarm contacts measured for contact resistance (<0.1 Ω); contact bounce and operate time recorded.
• SPA-bus communication test: Where SPAC 531 C module is present, serial communication verified using SPA-bus test software; setting read/write and event log retrieval confirmed.
• Insulation resistance: 500 V DC Megger test applied between all input/output terminals and chassis; minimum 100 MΩ acceptance criterion.
• Visual and mechanical inspection: COMBIFLEX connector pins inspected for corrosion and deformation; front panel display and LED indicators verified; case latch and sealing condition documented.