ABB REL650 series, Technical Manual

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Table 160: BRCPTOC (46) Non group settings (basic)
Name Values (Range) Unit Step Default Description
GlobalBaseSel 1 - 6 - 1 1 Selection of one of the Global Base Value
groups
7.14.6 Monitored data
Table 161: BRCPTOC (46) Monitored data
Name Type Values (Range) Unit Description
IUNBAL REAL - - Measured unbalance of phase
currents
7.14.7 Operation principle
Broken conductor check (BRCPTOC, 46) detects a broken conductor condition by
detecting the asymmetry between currents in the three phases. The current-measuring
elements continuously measure the three-phase currents.
The current asymmetry signal output PICKUP is set on if:
• The difference in currents between the phase with the lowest current and the phase
with the highest current is greater than set percentage
Pickup_ub of the highest phase
current
• The lowest phase current is below 50% of the minimum setting value Pickup_PH
The third condition is included to avoid problems in systems involving parallel lines. If a
conductor breaks in one phase on one line, the parallel line will experience an increase in
current in the same phase. This might result in the first two conditions being satisfied. If
the unsymmetrical detection lasts for a period longer than the set time
tOper the TRIP
output is activated.
The simplified logic diagram of the broken conductor check function is shown in figure
131
BRCPTOC (46) is disabled (blocked) if:
• The IED is in test mode and BRCPTOC (46) has been blocked from the HMI test
menu (
Blocked = Yes ).
• The input signal BLOCK is high.
The BLOCK input can be connected to a binary input of the IED in order to receive a block
command from external devices, or can be software connected to other internal functions
of the IED itself to receive a block command from internal functions.
1MRK 506 335-UUS A
Section 7
Current protection
277
Technical manual