ABB RELION REX640 Technical Manual page 456

Protection functions
The
operation according to the method of neutral point earthing so that in an isolated
network the
RCA
RCA_CTL. RCA_CTL affects the
The
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
"True", which turns the polarizing quantity by 180 degrees.
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 531: 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
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
B , Curve parameter C , Curve parameter D and Curve parameter E .
If a drop-off situation, that is, a fault suddenly disappears before the operate delay
is exceeded, the timer reset state is activated. The functionality of the timer in the
reset state depends on the combination of the
curve and Reset delay time settings. When the DT characteristic is selected, the
reset timer runs until the set
456
Characteristic angle setting is used in the "Phase angle" mode to adjust the
Characteristic angle (φ
= 0°. In addition, the characteristic angle can be changed via the control signal
Correction angle setting can be used to improve selectivity due the inaccuracies
For definitions of different directional earth-fault characteristics, see
Chapter 4.2.2.9 Directional earth-fault characteristics
) = -90° and in a compensated network φ
RCA
Characteristic angle setting.
Description
Also called operating angle, shows the angle difference be-
tween the polarizing quantity (Uo, U
ty (Io, I ).
2
The angle difference between the operating angle and Char-
acteristic angle, that is, ANGLE_RCA = ANGLE – Characteris-
tic 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). If the Opera-
tion mode setting is "IoCos", I_OPER is calculated as follows
I_OPER = Io x cos(ANGLE).
Curve parameter A , Curve parameter
Operating curve type , Type of reset
Reset delay time value is exceeded. When the IDMT
1MRS759142 F
Pol reversal to
in this manual.
) and operating quanti-
2
Operate delay time in the DT
Technical Manual
REX640