The ABB SPAJ 131 C is a secondary-injection, numerical overcurrent relay designed for the protection of three-phase power systems against short-circuit faults. It is a member of the SPACOM product family, widely recognized for its reliability in radial distribution networks and industrial power plants.
Product Parameters (Datasheet)
- Model Number: SPAJ 131 C
- Protection Function: Three-phase overcurrent (Low-set and High-set stages)
- Rated Current (In): 1 A or 5 A (Configurable via internal jumpers)
- Rated Frequency (fn): 50 Hz or 60 Hz
- Auxiliary Voltage (Uaux): 80–265 V AC/DC (Standard) or 18–80 V DC (Variant dependent)
- Low-set Stage (I>): 0.5–2.5 x In (Definite time or IDMT characteristics)
- High-set Stage (I>>): 0.5–40 x In or ∞ (Definite time)
- Thermal Withstand: 4 x In (Continuous), 100 x In (for 1 second)
- Communication: SPA-bus via plastic or glass fiber-optic cables
- Enclosure Rating: IP54 (Front panel), IP20 (Rear terminals)
Country of Origin
This protection relay is designed and manufactured in Finland by ABB, ensuring high European standards for electrical safety and precision engineering.
Application Fields
The SPAJ 131 C is utilized across various critical power sectors, including:
- Utility Substations: Primary short-circuit protection for outgoing radial feeders.
- Industrial Facilities: Protecting large three-phase motors and power transformers from thermal and magnetic damage.
- Building Automation: Monitoring main switchgear in commercial complexes and hospitals.
- Renewable Energy: Overcurrent protection for collector circuits in wind and solar farms.
Product Usage Instructions
- Mounting: Install the relay in a standard A1-size panel cutout. Ensure the chassis is connected to a reliable earth ground.
- CT Integration: Connect the three-phase current transformers to the rear terminals. Ensure the polarity matches the system requirements for accurate phase measurement.
- Characteristic Selection: Use the front-panel DIP switches to select between Definite Time (DT) or Inverse Definite Minimum Time (IDMT) curves (Normal, Very, Extremely, or Long-time inverse).
- Parameter Setting: Adjust the “Set Value” potentiometers for the low-set (I>) and high-set (I>>) current levels and their respective time delays.
- Operation: After a trip, the red LEDs on the front panel will indicate which phase caused the trip and which stage was activated. Press the “Reset” button to clear the targets after fault inspection.
Product Technical Description
The SPAJ 131 C is a microprocessor-based unit that converts incoming analog signals from CTs into digital data for real-time analysis. Technically, it utilizes Digital Signal Processing (DSP) to calculate the fundamental frequency components of the phase currents, making it immune to DC offsets and high-frequency harmonics. The draw-out design allows the internal relay module to be removed from the case for maintenance or replacement without disturbing the fixed field wiring, significantly reducing downtime during system upgrades.
Q&A (Common Questions)
Q: Can I use this relay for earth-fault protection? A: No, the SPAJ 131 C is specifically for three-phase overcurrent. For combined overcurrent and earth-fault protection, the SPAJ 140 C is the recommended model.
Q: Does the relay store event data? A: Yes, via the SPA-bus communication port, the relay can transmit event logs, pick-up values, and trip history to a central SCADA or monitoring station.
Q: What is the benefit of the IDMT setting? A: The IDMT (Inverse) characteristic allows the relay to coordinate with other protection devices by tripping faster for high-current faults and slower for minor overloads.
Q: Is the auxiliary power supply polarity sensitive? A: For the standard 80–265 V AC/DC version, the power supply is not polarity sensitive, allowing for flexible wiring in both AC and DC control systems.
Similar Model Recommendations
- ABB SPAJ 140 C (Combined phase and earth-fault protection)
- ABB SPAJ 110 C (Single-phase overcurrent and earth-fault relay)
- ABB REF 541 (Advanced feeder terminal successor)
- ABB REJ 521 (Compact numerical overcurrent relay)
- ABB SPAM 150 C (Specialized motor protection relay)
For more information on the ABB SPAJ 131 C and other protective relay solutions, please visit our technical catalog.
