ABB RELION Series, Technical Manual

Page: 289 / 804

If the Enable voltage limit setting is set to "True", the magnitude of the
polarizing quantity is checked even if Directional mode is set to "Non-
directional" or Allow Non Dir to "True".
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 due the inaccuracies
in the 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 319: 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
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).
1MRS758755 A
Section 4
Protection functions
REC615 and RER615 283
Technical Manual