SEL – 400G 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, bus, and step-up transformer protection in one package, making the relay an economical solution for an entire generation unit.



Advanced protection functions, like transverse differential protection, provide turn-to-turn fault detection, which allows for earlier fault detection, limits damage to your generator, and helps you return to service faster. Adaptive differential protection and a wide frequency tracking range (5–120 Hz) improve protection security. Dual frequency zones and autosynchronization offer smooth synchronization to the grid.

You can quickly integrate the SEL-400G into serial- or Ethernet-based communications. The new SEL Grid Configurator software allows you to quickly create, manage, and deploy device settings. Or, you can continue to use acSELerator QuickSet SEL-5030 Software for your configuration needs.



Advanced Generator and Unit Protection – Increase machine life by detecting faults and abnormal conditions before they cause permanent damage. The 18 current and 6 voltage inputs on the SEL-400G enable complex generator protection schemes or protection of other equipment, such as transformers.

Wide-range Frequency Tracking – The wide-range frequency tracking (5 to 120 Hz) ensures that all protection functions are secure and dependable across a wide range of system frequencies or generator speeds. This provides protection during events such as unit overs peed or inverter-driven startup.

Autosynchronizer – The built-in automatic synchronizer function eliminates the need for expensive external synchronizer equipment. The SEL-400G automatically synchronizes frequency, voltage, and phase control and connects the generator to the power system.

RTD-Based Thermal Protection – Use as many as two external SEL-2600 modules to acquire thermal data for alarm, monitoring, and trip functions in the SEL-400G.

Metering and Reporting – View generator autosynchronizer, Sequential Events Recorder (SER), and various event reports in COMTRADE format to analyze generator startup, shutdown, or system faults. Measure electrical, thermal, and generator run-time quantities and retrieve COMTRADE files via Ethernet FTP or IEC 61850 MMS.

Synchrophasor Data – Apply SEL synchrophasors (IEEE C37.118) to turn state estimation into state measurement and to provide early warning of potential system instability. The SEL-400G phasor measurement accuracy complies with IEEE C37.118.1/2-2011, -2014a.

Flexible Ethernet Communications – The four- and five-port Ethernet communications card options enable you to communicate using a variety of protocols, including FTP, HTTP, DNP3, PTPv2, PRP, Telnet, synchrophasors, and IEC 61850 Edition 2. The SEL-400G can be configured with a five-port Ethernet card supporting PRP or failover functionality to increase system availability, as well as the Precision Time Protocol Version 2 (PTPv2) on process bus or station bus ports for time synchronization. Use network monitoring features in the relay to further improve system availability by actively monitoring each redundant path to detect communications network failures.

The five-port card also features dedicated ports and IP addresses for station bus and engineering access networks to provide selective access control. All ports support SFP transceivers. Single- and multimode communications options provide increased flexibility. All ports support 100 Mbps SFP transceivers, and process bus ports also support 1 Gbps SFP transceivers.

Serial Communications – All four independent EIA-232 serial ports support SEL ASCII, Compressed ASCII, SEL Fast Operate, SEL Fast Meter, SEL Fast SER, enhanced SEL Mirrored Bits communications, Ymodem, and DNP3 Level 2 Outstation as well as dial-out, Virtual Terminal, and communications with SEL-2600 series RTD modules.

Multiple Configuration Platforms – The SEL-400G can be configured, commissioned, and managed using either SEL Grid Configurator or QuickSet. Select the choice that best fits your application and software transition needs.

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