Sel 551 - Timer Specifications

1.8
SEL-551 Relay Instruction Manual Date Code 20110408
Introduction and Specifications
Timer Specifications
is significantly degraded. Combining the two filters provides an elegant
solution for ensuring dependable phase instantaneous overcurrent element
operation.
Timer Specifications
The SEL-551 has reclosing relay timers, programmable timers, and other
timers (see Section 4: Setting the Relay). All timers are set in cycles, in 1/8
cycle (0.125 cycle) increments. The relay rounds the entered time setting up or
down to the nearest 1/8 cycle. For example:
Enter setting
79OI1 = 264.685
and the relay rounds it down to
79OI1 = 264.625
Enter setting
SV10PU = 1567.318
and the relay rounds it up to
SV10PU = 1567.375
The timing accuracy for these timers is: ±0.25 cycles and ±0.1 percent of
setting.