ABB DPU 1500R Instruction Book page 174

ABB Distribution Protection Unit 1500R/2000R
Sample Operation
Condition 1. Feeder and Bus DPU1500R/2000R OK: Feeder Fault (see Figure 13-17).
The pickup alarm (PUA) picks up the pickup auxiliary relay (PA). The PA contact disables the 50-1 functions of the
bus DPU1500R/2000R. The feeder relay trips for the fault and recloses after the set open interval time expires.
All auxiliary self-check relays (74/Fn) are picked up, blocking the bus DPU1500R/2000R from tripping the feeder
PUA PUA
F1 F2
PA
1
Pickup alarm (PUA) for
feeder relay 3 closes,
causing PA relay to
open its contact.
breaker.
Condition 2: Feeder and Bus DPU1500R/2000R OK: Bus Fault (see Figure 13-18).
The pickup auxiliary relay (PA) is not energized, and therefore the 50-1 function of the bus DPU1500R/2000R is
enabled. The 50-1 function trips the bus breaker after 0.05 seconds through the closed contacts of the energized (74/
Fn) relays.
13-12
PA
PUA
50-1 DISABLED
F3
50-1 TRIP
DPU
B
51&
74
F1
50-2
74
TRIP
F2
74
F3
B
Fault
Figure 13-17. Feeder Fault: Bus and Feeder Relays OK
website:www.abb.com/papd
In the presence of pickup from feeder
relay #3, the PA relay disables the 50-1
2
function of the bus DPU1500R/2000R.
Aux
B
50-1
TRIP
4
Bus DPU1500R/2000R provides bus
protection and backup F3 breaker failure
based on 50-2 and 51 settings.
DPU
F3
Trip
F3
X
Aux
B
74
Sensing the fault, the
F3
feeder DPU1500R/2000R
trips the breaker.
3
Applications Notes
9/99