Description

Brief Product Description

The ABB SPAJ140C is a sophisticated numerical protection unit that integrates multi-stage overcurrent and earth-fault detection into a single compact housing. This secondary relay interfaces with current transformers to provide rapid fault isolation, alarm signaling, and coordination for industrial and utility power networks.

​Product Description

The ABB SPAJ140C operates as a comprehensive protection solution for feeders and motors, effectively managing both phase overcurrent and neutral earth-fault conditions. This numerical relay continuously samples current transformer inputs to detect abnormalities within the power system. Upon detecting a breach of programmed thresholds, the processor executes high-speed tripping commands or alarm signals to safeguard connected equipment. Because the unit features both low-set and high-set stages, it provides a dual-layer defense: the low-set stages handle sustained overloads, while the high-set stages respond to severe short circuits in as little as 40 ms.

Advanced Time-Current Coordination

A key advantage of the SPAJ140C lies in its versatile time-delay logic. Engineers can choose between definite-time characteristics or Inverse Definite Minimum Time (IDMT) curves to achieve perfect coordination with upstream and downstream protective devices. The module includes six distinct curve profiles, featuring four standardized international curves (Normal, Very, Extremely, and Long-time Inverse) compliant with IEC 60255 and BS 142 standards. Furthermore, the specialized RI and RXIDG curves allow for niche applications, ensuring the relay adapts to the specific thermal limits of the protected machinery.

System Integration and Control Features

Beyond primary protection, the SPAJ140C enhances system intelligence through configurable output relays and binary inputs. These outputs can initiate auto-reclosing sequences, trigger remote alarms, or provide blocking signals to co-protection relays to prevent unnecessary tripping. The integrated binary input serves as a flexible control port, allowing operators to manually reset latched signals or toggle between setting groups dynamically. Consequently, this relay reduces hardware complexity by consolidating multiple monitoring functions into a single robust Swedish-engineered chassis.

Technical Specification Table