Table 300: Typical current and voltage choices for directional feature
Set value for the
parameter
CurrentInput
Set value for the
parameter
VoltageInput
Comment
PosSeq PosSeq Directional positive sequence overcurrent function is
obtained. Typical setting for
RCADir
is from -45° to -90°
depending on the power
NegSeq -NegSeq Directional negative sequence overcurrent function is
obtained. Typical setting for
RCADir
is from -45° to -90°
depending on the power system voltage level (X/R ratio)
3ZeroSeq -3ZeroSeq Directional zero sequence overcurrent function is
obtained. Typical setting for
RCADir
is from 0° to -90°
depending on the power system grounding (that is, solidly
grounding, grounding via resistor)
Phase1 Phase2-Phase3 Directional overcurrent function for the first phase is
obtained. Typical setting for
RCADir
is +30° or +45°
Phase2 Phase3-Phase1 Directional overcurrent function for the second phase is
obtained. Typical setting for
RCADir
is +30° or +45°
Phase3 Phase1-Phase2 Directional overcurrent function for the third phase is
obtained. Typical setting for
RCADir
is +30° or +45°
Unbalance current or voltage measurement shall not be used when the directional
feature is enabled.
Two types of directional measurement principles are available, I & V and IcosPhi&V.
The first principle, referred to as "I & V" in the parameter setting tool, checks that:
• the magnitude of the measured current is bigger than the set pick-up level
• the phasor of the measured current is within the operating region (defined by the
relay operate angle, ROADir parameter setting; see figure
288).
Section 10 1MRK505222-UUS C
Multipurpose protection
572
Technical reference manual
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