The Characteristic angle setting is used in the "Phase angle" mode to adjust the
operation according to the method of neutral point earthing so that in an isolated
network the Characteristic angle (φ
RCA
) = -90° and in a compensated network
φ
RCA
= 0°. In addition, the characteristic angle can be changed via the control
signal RCA_CTL. RCA_CTL affects the Characteristic angle setting.
The Correction angle setting can be used to improve selectivity when there are
inaccuracies due to measurement transformers. The setting decreases the operation
sector. The correction can only be used with the "IoCos" or "IoSin" modes.
The polarity of the polarizing quantity can be reversed by setting the Pol reversal
to "True", which turns the polarizing quantity by 180 degrees.
For definitions of different directional earth-fault characteristics,
see the Directional earth-fault characteristics section in this manual.
For definitions of different directional earth-fault characteristics,
refer to general function block features information
The directional calculation module calculates several values which are presented in
the monitored data.
Table 288: Monitored data values
Monitored data values
Description
FAULT_DIR The detected direction of fault during fault
situations, that is, when START output is active.
DIRECTION The momentary operating direction indication
output.
ANGLE Also called operating angle, shows the angle
difference between the polarizing quantity (Uo,
U
2
) and operating quantity (Io, I
2
).
ANGLE_RCA The angle difference between the operating
angle and
Characteristic angle
, that is,
ANGLE_RCA = ANGLE –
Characteristic angle
.
I_OPER The current that is used for fault detection. If the
Operation mode
setting is "Phase angle", "Phase
angle 80" or "Phase angle 88", I_OPER is the
measured or calculated residual current. If the
Operation mode
setting is "IoSin", I_OPER is
calculated as follows I_OPER = Io x sin(ANGLE).
If the
Operation mode
setting is "IoCos", I_OPER
is calculated as follows I_OPER = Io x
cos(ANGLE).
Monitored data values are accessible on the LHMI or through tools via
communications.
1YHT530004D05 D Section 4
Protection functions
615 series 277
Technical Manual
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