ABB RELION REB500 Technical Manual page 52

Section 5
Bay protection functions
Zero-sequence compensation of double-circuit lines
The magnitude and phase-angle of the zero-sequence compensation factor for a double-
circuit line are set using parameters
Zones 1 and 2, the overreaching zone and the reverse zone.
Directional unit
Each distance zone has its own directional measuring unit. The voltage used for measurement
depends on the amplitude of the fault voltage in relation to the parameter
fault voltage is used, providing it is higher than the setting of
from the healthy voltage and the memory voltage is used when it falls below. The
recommended settings are 0.1 UN for conventional VTs.
Should correct determination of direction not be possible (reference voltage too low or
memory voltage decayed), the setting of the parameter
protection blocks or trips:
• Block — Protection blocks all zones (definitive zone only if directional)
• Trip — Protection trips
• Cond. trip — Protection blocks unless the instantaneous and preceding zones are in
opposite directions, in which case the protection trips.
Overreaching zone (OR)
The settings including the designation 4/OR (X (4/OR) delay (4/OR)) can be used either for a
fourth measuring zone or a completely independent overreaching zone (but not for both at the
same time) by appropriately setting the parameter
In applications requiring a fourth zone, the measuring unit of the second zone is used for
overreaching. An overreaching zone is necessary for the switch-onto-fault and zone extension
logics and for overreaching transfer tripping schemes.
Reverse zone (BACK)
A reverse measuring zone is used in a blocking scheme and also the logic for detecting a
reversal of fault energy direction. It is set using the parameters
RRE (BACK) which have setting ranges from 0 to 300 Ω/ph.
and
Note that:
• for underimpedance starting (UZ):
With the exception of the load discrimination defined by the parameters
AngleLoad , the reverse zone operates independently of the starters.
• for overcurrent starting (OC):
The reverse zone is only in operation when an overcurrent starter (
• The binary input (Ext Blk UZ) blocks operation regardless of the starter mode for the
reverse zone.
• Signal output: Meas Bward
• Measurement of the reverse zone only takes place while the first zone is active, that is, the
Meas Bward signal resets at the latest at the end the second time step.
Time steps (Delay)
The operating time of every activated distance zone (parameter
parameter
(4/OR) is also associated with a logic, which determines whether it applies to Zone 4 or to the
overreaching zone, that is, if Delay (4/OR) < Delay (2), it applies to the overreaching zone,
otherwise to Zone 4.
The set times must satisfy the following relationships:
46
Delay , which has a setting range of 0 to 10 s in steps of 0.01. The parameter Delay
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k0m and k0mAng . This compensation only applies to
MemDirMode determines whether the
Delay (4/OR) .
1MRK 505 406-UEN B
UminFault . The
UminFault and a voltage derived
GUID-9E13EFC1-370B-4EC2-A33B-72FB1A9E9C5B v1
GUID-5C7E7430-152E-46A3-9CA7-2CEC0AE6519B v1
X (BACK) , R (BACK) , RR (BACK)
RLoad and
IStart ) has picked up.
GUID-74E9FA23-CFF7-4A68-A9A9-68480D59B009 v1
X <> 0) is determined by the
Bay protection functions REB500
Technical manual