ABB DPU 1500R Instruction Book page 175

9/99
B
Fault
Condition 3: A Feeder DPU1500R/2000R Fails or Is Withdrawn from Its Case: Feeder Fault (see Figure 13-14)
The self-check alarm contact de-energizes the (74/Fn) relay. The (74/Fn) contact in the feeder trip circuit closes. The
PA relay is not energized, thereby enabling the 50-1 functions of the bus DPU1500R/2000R. The bus DPU1500R/
2000R's 50-1 functions energize the Aux/B relay, which trips the feeder breaker with no reclosing.
Bus DPU1500R/
2000R provides
backup to feeder
breaker failure
based on 50-2
and 51 settings.
3
Figure 13-19. Feeder Fault: Feeder 3 DPU1500R/2000(R) Has Failed
Applications Notes
In the absence of pickup from the feeder relays,
PA
relays, the PA relay enables the 50-1 function
2
of the bus DPU1500R/2000R.
50-1 ENABLE
50-1 TRIP
Aux
DPU
B
B
50-1
TRIP
51& 74
F1
50-2
74
TRIP
F2
74
F3
X
F3
Figure 13-18. Bus Fault: Bus and Feeder Relays OK
6
PA
50-1 ENABLE
DPU
B
51&
74
F1
50-2
74
TRIP
F2
74
F3
B
Open 74/F3 prevents
tripping of bus breaker.
Fault
ABB Distribution Protection Unit 1500R/2000R
Bus DPU1500R/2000R trips bus
4
breaker based on 50-1 settings.
74/Fn contacts remain closed
3
unless a feeder relay fails.
DPU
Aux
F3
B
74
F3
Trip Energized self-check alarm
keeps the 74/Fn relay open.
1
In the absence of pickup from the feeder
relays, the PA relay enables the 50-1
2
function of the bus DPU1500R/2000R.
50-1 TRIP
Aux
B
Bus DPU1500R/2000R trips based on 50-1
50-1
settings and energizes Aux/B relay.
TRIP
4
Failed Feeder
Relay
DPU
Aux
F3
B
74
F3
Trip
F3
X
website:www.abb.com/papd
5
Closed Aux/B relay trips
the feeder breaker.
When feeder DPU1500R/2000R
fails, the self-check alarm
de-energizes the 74/Fn
1
relay and the contact closes.
13-13