SEL-387/SEL-387A Current Differential and Overcurrent Relay
The SEL-387 Current Differential and Overcurrent Relay provides protection, control, and metering for transformers, machines, buses, breakers, and feeders. Features include four three-phase current inputs with independent restrained and unrestrained differential protection, programmable single- or dual slope differential characteristic, circuit breaker monitor, battery voltage monitor, and enhanced SELOGIC® Control Equations.
Front- and Rear-Panel Diagrams
Protect power transformers with as many as four windings using a combination of single- or dual-slope percentage differential characteristics, overcurrent protection, and Restricted Earth Fault (REF) protection.
Reduce total project costs through remote communications capa-bilities and elimination of external control switches and indicating lamps. Use remote communications capabilities for control, moni-toring, and alarm purposes.
Locally control relay operation, and initiate or block automation sequences from remote sites or control systems.
Simplify fault and system disturbance analysis with event reports and sequential events recorder. Use breaker contact wear and substation battery voltage monitors to efficiently dispatch mainte-nance resources.
Specify optional thermal modeling per IEEE C57.91:1995 for mineral-oil immersed transformers. Use the thermal element to activate a control action or to issue an alarm when your transformer is in danger of excessive insulation aging or loss-of-life.