Over-current protection relay / configurable / programmable / panel-mount
SEL-551 Schweitzer Engineering Laboratories


  • Measured/monitored value:


  • Other characteristics:

    configurable, programmable, panel-mount, for generators


The SEL-551 Overcurrent/Reclosing Relay replaces the many relays, control switches, and wiring required in traditional distribution substation protection and control panels. The relay also replaces line recloser control packages at a fraction of the cost. Protect distribution feeders, distribution buses, transformers, capacitors, and circuit breakers. Select the "fast bus" trip scheme when protecting a distribution bus. Choose "fast" or "slow" curve operation to allow for cold load pickup. Connect the separate neutral current input to accommodate core-balance current transformers, separate neutral current transformers, tertiary winding current transformers, or CT ground residual circuits.


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