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Section 11
Checking the directionality
246
•
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/IED Settings/Impedance protection/
DirectionalImpedance
3.
The directionality of the load current is shown by the High speed distance
protection ZMFPDIS or ZMFCPDIS under the HMI menu: Main menu/Test/
Function status/Impedance protection/HighSpeedDistance or by the
directional function ZDRDIR or ZDMRDIR and it is available under the HMI
menu: Main menu/Test/Function status/Impedance protection/
DirectionalImpedance
The following will be shown if the load current flows in forward (exporting)
direction:
•
L1Dir = Forward
•
L2Dir = Forward
•
L3Dir = Forward
The following will be shown if the load current flows in the reverse direction
(importing):
•
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 available under the HMI menu:Main menu/Configuration/
Analog modules).
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 under
the HMI menu: Main menu/Configuration/Analog modules) 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 load
impedance has an angle which is outside the above given valid angles for
determining forward or reverse direction.
1MRK 506 355-UEN A
Line distance protection REL670 2.1 IEC
Commissioning manual
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