4-16
BE1-51/27R - Installation
Feeder
BE1-51 (51)
(Breaker F)
0.5 to 12 A
Very inverse timing
800/5 CTs
No instantaneous
Pickup set to 6 A
Time Dial set to 08
Phase Directional
BE1-67, (67)
Breaker L)
Definite timing (B3)
0.5 to 12 A
3000/5 CTs
Pickup set to 0.5 A
Time Dial set to 02
Generator Reactance
Subtransient
0.18
(Per Unit)
Transient
0.25
Steady state
1.5
Figure 4-16. Setting Example
Downstream current in Table 4-1 is the current in the downstream relay with which the BE1-51/27R elements
must coordinate. The currents are the changes resulting from the fault assuming a driving point voltage of 11
kV. Actual currents will be the sum of the table values plus the pre-fault load currents. Transient level currents
are based on use of the generator transient reactance. Steady-state level currents are based on use of
generator steady-state reactance and assuming no generator regulator boost. Note that the table values apply
for 3-phase faults. Transient level currents in generators for a phase-to-phase fault will be about equal to the
3-phase current values. Steady-state level currents in the generators will be higher for a phase-to-phase fault.