• load current > 5% of base current
• Otherwise the settings IMinOpPE and IMinOpPP for ZDRDIR or
ZDMRDIR are available under the HMI menu: Main menu/
Settings/Setting group N/Impedance protection/
DirectionalImpedance(RDIR)
The primary load impedance must have an angle (PHI) between the setting
angles for the directional lines. In case of default settings this means:
• for forward (exported) load: -15 deg < PHI < 115 deg
• for reverse (imported) load: 165 deg < PHI < 295 deg
The settings for forward load: - ArgDir < PHI < ArgNegRes and the settings
for reverse load: 180 deg - ArgDir < PHI < 180 deg + ArgNegRes included in
the directional functions ZDRDIR or ZDMRDIR are available under the HMI
menu:
• Main menu/Settings/Setting group N/Impedance protection/
DirectionalImpedance(RDIR)
3. The directionality of the load current is shown by the directional function
ZDRDIR or ZDMRDIR and it is available under the HMI menu: Main menu/
Test/Function status/Impedance protection/DirectionalImpedance(RDIR)
If the load current flows in forward (exporting) direction there will be shown:
• L1Dir = forward
• L2Dir = forward
• L3Dir = forward
If the load current flows in the reverse direction (importing) there will be shown:
• L1Dir = reverse
• L2Dir = reverse
• L3Dir = reverse
Compare this result with the information given by the external equipment, it
must be the same. If the direction of the three phases is not the same, this is a
sign of incorrect connection of the voltage or current transformers serving the
distance protection function. It is also possible that there is a wrong setting for
the earthing point for one or more of the CTs serving distance protection (the
setting name is: CTStarPoint).
If the directional function shows forward when it should show reverse (or vice-
versa) for all the three phases, this probably means a wrong connection of CTs
and/or VTs serving the distance protection, or it can mean a wrong setting of
earthing point (the setting name is : CTStarPoint) for all the three CTs, or it
could mean a wrong setting for the pre-processing blocks
(3PhaseAnalogGroup) connected to the CTs/VTs and serving the distance
protection (verify that no wrong negation has been set; the setting name is:
Negation).
If the directional function shows “No direction” for all the three phases it can
mean that the load current is below the minimum operating current or that the
Section 16 1MRK 502 029-UEN A
Checking the directionality
230
Installation and commissioning manual
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