ABB RELION REX640 Technical Manual page 424

Section 4
Protection functions
418
= 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
The DIRECTION output indicates on which operating sector the operating quantity is
measured. The FAULT_DIR output indicates in which operation sector the fault
current is measured. The output is operational once the function is started.
The directional calculation module calculates several values which are presented in
the monitored data.
Table 478: Monitored data values
Monitored data values
ANGLE
ANGLE_RCA
I_OPER
Timer
Once activated, the timer activates the START output. Depending on the value of the
Operating curve type setting, the time characteristics are according to DT or IDMT.
When the operation timer has reached the value of Operate delay time in the DT mode
or the maximum value defined by the inverse time curve, the OPERATE output is
activated.
When the user-programmable IDMT curve is selected, the operation time
characteristics are defined by the parameters Curve parameter A, Curve parameter B,
Curve parameter C, Curve parameter D and Curve parameter E.
section in this manual.
Description
Also called operating angle, shows the angle
difference between the polarizing quantity (Uo,
U ) and operating quantity (Io, I
2
The angle difference between the operating angle
Characteristic angle , that is, ANGLE_RCA =
and
Characteristic angle .
ANGLE –
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).
Operation mode setting is "IoCos", I_OPER
If the
is calculated as follows I_OPER = Io x
cos(ANGLE).
1MRS759142 C
).
2
REX640
Technical Manual