ABB RELION REX640 Technical Manual page 335

1MRS759142 C
REX640
Technical Manual
the fictive voltage is unusable, the fault direction cannot be determined. The fictive
voltage can be unusable for two reasons:
• The fictive voltage is discarded after Voltage Mem time
• The phase angle cannot be reliably measured before the fault situation.
DPHxPDOC can be forced to the non-directional operation with the NON_DIR input.
When the NON_DIR input is active, DPHxPDOC operates as a non-directional
overcurrent protection, regardless of the Directional mode setting.
GUID-9252789C-52F7-4989-B1D0-032A98E365B7 V1 EN
Figure 184: Operating zones at minimum magnitude levels
The DIRECTION output indicates on which operating sector the current is measured.
The value combines phase-specific directions which are available in monitored data
as DIR_A, DIR_B and DIR_C.
Level detector
The measured phase currents are compared phasewise to the set Start value. If the
measured value exceeds the set Start value, the level detector reports the exceeding of
the value to the phase selection logic. If the ENA_MULT input is active, the Start value
setting is multiplied by the Start value Mult setting.
Section 4
Protection functions
329