ABB RET670 Commissioning Manual page 290

Section 13
Checking the directionality
284
• 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 504 165-UEN A
Transformer protection RET670 2.2 IEC
Commissioning manual