ABB REG670 - Page 586

Set value for the
parameter
CurrentInput
Set value for the
parameter
VoltageInput
Comment
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 & U and IcosPhi&U.
The first principle, referred to as "I & U" 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
272).
U=-3U0
Ipickup
Operate region
I=3Io
mta line
RCADir
ROADir
en05000252.vsd
IEC05000252 V1 EN
Figure 272: I & U directional operating principle for CVGAPC function
where:
RCADir is -75°
ROADir is 50°
The second principle, referred to as "IcosPhi&U" in the parameter setting tool, checks
that:
• that the product I·cos(Φ) is bigger than the set pick-up level, where Φ is angle
between the current phasor and the mta line
• that the phasor of the measured current is within the operating region (defined by
the I·cos(Φ) straight line and the relay operate angle, ROADir parameter setting;
see figure 272).
Section 11 1MRK502052-UEN B
Multipurpose protection
580
Technical manual