Setting Guidelines - ABB REL650 Applications Manual

1MRK 506 334-UUS A
6.3.3
Application manual
zone distance protection, mho characteristic (ZQMPDIS, 21) without interfering with the
load.
The load encroachment algorithm and the blinder functions are always activated in the
phase selector. The influence from these functions on the zone measurement
characteristic has to be activated by switching the setting parameter LoadEnchMode in
ZQMPDIS (21) for the respective measuring zone(s) to Enabled.

Setting guidelines

GlobalBaseSel: Selects the global base value group used by the function to define (IBase),
(VBase) and (SBase).
INRelPG: The setting of INRelPG for release of the phase-to-ground loop is by default set
to 20% of IBase. The default setting is suitable in most applications.
The setting must normally be set to at least 10% lower than the setting of 3I0BLK_PPto
give priority to open phase-to-ground loop. INRelPG must be above the normal un-
balance current (3I ) that might exist due to un-transposed lines.
0
3I0BLK_PP: The setting of 3I0BLK_PP is by default set to 40% of IBase, which is
suitable in most applications.
I1LowLevel: The setting of the positive current threshold I1LowLevel used in the sequence
based part of the phase selector for identifying three-phase fault, is by default set to 10% of
IBase.
The default setting is suitable in most cases, but must be checked against the minimum
three-phase current that occurs at remote end of the line with reasonable fault resistance.
IMaxLoad: The setting IMaxLoad must be set higher than the maximum load current
transfer during emergency conditions including a safety margin of at least 20%. The
setting is proposed to be according to equation 66:
IMaxLoad =1.2 ILoad
EQUATION1614 V2 EN
where:
1.2 is the security margin against the load current and
ILoad is the maximal load current during emergency conditions.
The current ILoad can be defined according to equation 67.
Section 6
Impedance protection
(Equation 66)
147