Operation Principle - ABB REL650 series Technical Manual

1MRK 506 335-UUS A
12.4.6
12.4.6.1
12.4.6.2
Technical manual

Operation principle

Zone extension
The overreaching zone is connected to the input EXACC. For this reason, configure the
ARREADY functional input to a READY functional output of a used autoreclosing
function or via the selected binary input to an external autoreclosing device, see
figure 243.
This will allow the overreaching zone to trip instantaneously.
IEC05000157 V1 EN
Figure 243: Simplified logic diagram for local acceleration logic
After the autorecloser initiates the close command and remains in the reclaim state, there
will be no ARREADY signal, and the protection will trip normally with step distance time
functions.
In case of a fault on the adjacent line within the overreaching zone range, an unwanted
autoreclosing cycle will occur. The step distance function at the reclosing attempt will
prevent an unwanted retrip when the breaker is reclosed.
On the other hand, at a persistent line fault on line section not covered by instantaneous
zone (normally zone 1) only the first trip will be "instantaneous".
The function will be blocked if the input BLOCK is activated (common with loss-of-load
acceleration).
Loss-of-Load acceleration
When the "acceleration" is controlled by a loss-of-load, the overreaching zone used for
"acceleration" connected to input LLACC is not allowed to trip "instantaneously" during
normal non-fault system conditions. When all three-phase currents have been above the
set value MinCurr for more than setting tLowCurr, an overreaching zone will be allowed
Section 12
Scheme communication
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