To verify the settings in the most common back-up trip mode 1 out of 3 it is sufficient to
test phase-to-ground-faults.
At mode 2 out of 4 the Phase current setting, Pickup_PH can be checked by single phase
injection where the return current is connected to the summed current input. The value of
residual (EF) current IN set lower than Pickup_PH is most easily checked in backup trip
mode 1 out of 4.
6.3.10.1 Checking the phase current operate value, Pickup_PH
Check the current level IP> where setting FunctionMode = Current and setting
BuTripMode = 1 out of 3 or 2 out of 4 as set under Main menu/Settings/IED Settings/
Current/CSPRBRF(50BF)/CSPRBRF:1.
1. Apply the fault condition, including INITIATION of CSPRBRF (50BF), with a
current below set Pickup_PH.
2. Repeat the fault condition and increase the current in steps until a trip occurs.
3. Compare the result with the set Pickup_PH.
4. Disconnect AC and INITIATE input signals.
If “No IPickup check” or “Retrip off” is set, only back-up trip can be
used to check set Pickup_PH.
6.3.10.2 Checking the residual (GF) current operate value
IN>
set below IP>
Check the low set IN> current where setting FunctionMode = Current and setting
BuTripMode = 1 out of 4 as set under Main menu/Settings/IED Settings/Current/
CSPRBRF(50BF)CSPRBRF:1.
1. Apply the fault condition, including initiation of CSPRBRF 50BF, with a current
just below set Pickup_N.
2. Repeat the fault condition and increase the current in steps until trip appears.
3. Compare the result with the set Pickup_N.
4. Disconnect AC and initiation input signals.
6.3.10.3 Checking the re-trip and back-up times
The check of the set times can be made in connection with the check of operate values
above. Choose the applicable function and trip mode, such as FunctionMode = Current
and setting RetripMode = No CBPos Check as set under Main menu/Settings/IED
Settings/CSPRBRF(50BF)/Current/CSPRBRF:1.
1MRK 505 293-UUS A Section 6
Testing functionality
65
Commissioning manual
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