ABB 426E1170 Loss Of Excitation Protection Relay

The ABB 426E1170 Loss of Excitation Protection Relay is a dedicated protection module designed for ABB’s Circuit Shield Power T&D protection systems, monitoring the excitation condition of connected machinery and initiating protective actions when excitation is lost.

Identified by the part number 426E1170, this relay supports a 48/125 VDC control supply (DD4), aligning with ABB’s low‑voltage supervisory schemes used in substation protection panels.

In practical terms, the device provides loss‑of‑excitation protection for synchronous generators and related equipment within medium- to high-voltage distribution environments, helping maintain system stability by detecting excitation faults and triggering appropriate protective responses.

The 426E1170 is typically integrated within ABB protection architectures alongside other Circuit Shield components to form a cohesive, redundant protective strategy for power delivery infrastructure.