Application Scenarios:

In a 10kV industrial ring main unit supplying a chemical processing plant, the ABB SPAJ141C-AA​ relays are deployed on each outgoing feeder to critical pumps and reactors. During a cable insulation breakdown on a pump feeder, the SPAJ141C-AA​ detected a rising earth-fault current. Utilizing its pre-configured “Very Inverse” characteristic, the relay calculated a coordinated trip time that allowed downstream fuses to clear a minor fault first; when they failed to act, the SPAJ141C-AA​ initiated a definitive trip command. This selective coordination, managed entirely by the relay’s logic, prevented a cascading outage that would have shut down the entire process line, isolating only the faulty section and maintaining production continuity for the rest of the facility.

 

Parameter:

Main Parameters	Value/Description
Product Model​	ABB SPAJ141C-AA​
Manufacturer​	ABB Ltd.
Product Category​	Numerical Protection Relay (Overcurrent & Earth-Fault)
Rated Frequency​	50 Hz (Standard for -AA suffix)
Auxiliary Supply​	80–265 V AC/DC (Wide Range)
Current Inputs​	3 Phase + 1 Neutral (1A or 5A CT secondary)
Protection Functions​	3-Stage Phase OC, 2-Stage Earth Fault, CB Failure
Time Characteristics​	Definite Time (DT) or IDMT (Normal, Very, Extremely Inverse)
Communication​	RS-485/SPA-Bus (via optical or electrical port)
Control Outputs​	2 Trip Relays, 2 Signal Relays
Operating Temperature​	-25°C to +55°C
Mounting​	Panel Mount (144mm x 144mm cutout)
Standards​	IEC 60255, CE Marked

 

 

Technical Principles and Innovative Values:

• Innovation Point 1: Advanced Coordination with Flexible Curve Selection:​ Unlike basic fixed-time relays, the SPAJ141C-AA​ implements a sophisticated Inverse Definite Minimum Time (IDMT) algorithm. It allows engineers to select from multiple standard curves (Normal Inverse, Very Inverse, Extremely Inverse) and adjust time multipliers. This enables precise grading coordination across the network, ensuring that the relay closest to a fault operates first, thereby minimizing the outage zone and improving system reliability.
• Innovation Point 2: Integrated Circuit Breaker Failure Protection (CBFP):​ The relay incorporates a built-in CBFP function. If the relay issues a trip command but the primary circuit breaker fails to open (detected by persistent fault current), the SPAJ141C-AA​ automatically initiates a backup trip signal to the upstream breaker after a settable time delay. This “defense in depth” feature prevents a single breaker failure from escalating into a major system-wide blackout.
• Innovation Point 3: SPA-Bus Communication for Distribution Automation:​ The SPAJ141C-AA​ was an early adopter of ABB’s SPA-Bus protocol (via RS-485), allowing it to be integrated into a SCADA or Distribution Automation system. It can transmit real-time measured values, event records, and disturbance data to a central control room, enabling remote monitoring and reducing the need for physical inspections in hazardous or remote substations.

 

Application Cases and Industry Value:

Case Study: Mining Infrastructure MV Network UpgradeA large open-pit mining operation in Australia was experiencing frequent nuisance trips on its 6.6kV distribution feeders due to transient overcurrents from heavy machinery starts. The existing electromechanical relays lacked selectivity. The site upgraded to ABB SPAJ141C-AA​ relays. Engineers utilized the “Long-Time Inverse” characteristic for the low-set overcurrent stage (I>) to ride through motor starting currents, while setting a sensitive earth-fault stage (Io>) to detect cable faults ignored by the old relays. Post-upgrade, the site recorded a 60% reduction in unexplained trips. The SPAJ141C-AA‘s event log was crucial in diagnosing a recurring ground fault, which was traced to a damaged cable trench, allowing preemptive repair during a planned shutdown.