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Advanced Generator Protection System


The SEL-400G offers primary and backup protection for generators of all sizes and types, including hydro, pumped-storage hydro, steam turbine, and combustion gas turbine generators. It combines generator, generator bus, and generator step-up transformer protection in one package, making the relay an economical solution for an entire plant.

Advanced protection functions, like stator and rotor turn-to-turn fault detection, allow you to detect faults earlier, limit damage to your generator, and return to service faster. Adaptive differential protection and a wide frequency tracking range (5–120 Hz) improve your protection security. Dual frequency zones and autosynchronization offer smooth synchronization to the grid.

Starting At

$10,000 USD

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Advanced Generator Protection—Two independent universal differential elements provide protection for the generator and GSU transformer in a single relay. The SEL-400G also offers 18 current inputs, 6 voltage inputs, wide-range frequency tracking (5–120 Hz), advanced antimotoring protection, loss-of-field protection, and more.

Pumped Storage Logic—This feature enables pumped storage hydropower protection without the need for external relays to switch CT wiring, which lowers costs and improves reliability.

Stator Ground Fault Protection—Achieve passive and active ground fault detection across 100 percent of the stator winding without sacrificing security. The stator winding ground fault protection elements include integrating timers that detect intermittent ground faults and isolate the generator before the fault evolves into a permanent fault.

Rotor/Field Winding Protection—Applying the SEL-2664 Field Ground Module with the SEL-400G allows you to protect your system against rotor/field winding short circuits. With the field ground protection element, the first fault will trigger an alarm and a second fault results in a trip signal.

Simplified Settings Management—SEL Grid Configurator is a new configuration software tool that delivers a modern user experience, helps increase efficiency, and improves settings insights. It features a spreadsheet-style editor, powerful protection visualization, comprehensive reporting, custom filters, and multiple-device settings management.

Communication and Integration— Quickly integrate the SEL-400G into serial- or Ethernet-based communications with IEC 61850, the IEC 62439 Parallel Redundancy Protocol (PRP), Mirrored Bits communications, Modbus, DNP3, and other protocols.


400G Front Callouts400G Back Callouts