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
236:
EQUATION1614 V2 EN (Equation 236)
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 237.
EQUATION1615-ANSI V1 EN (Equation 237)
where:
Smax is the maximal apparent power transfer during emergency conditions and
VLmn is the phase-to-phase voltage during the emergency conditions at the IED location.
Load encroachment
The load encroachment function has two setting parameters, RLd for the load
resistance and LdAngle for the inclination of the load sector (see figure
138).
1MRK504116-UUS C Section 3
IED application
313
Application manual
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