ABB RELION REX640 Technical Manual page 1135

1MRS759142 F
I_COM_ANGL_B
I_COM_ANGL_B
I_COM_ANGL_C
I_COM_ANGL_C
If external fuses are used, the direction of an unbalance current is opposite to that
of the bank where internal fuses are in use.
Table 1078: Detection of element failure location for external fuse capacitor bank
Name of the phase angle
I_COM_ANGL_A
I_COM_ANGL_A
I_COM_ANGL_B
I_COM_ANGL_B
I_COM_ANGL_C
I_COM_ANGL_C
Level detector 1
The phasewise-compensated unbalance currents I_COM_AMPL_A, I_COM_AMPL_B
and I_COM_AMPL_C are compared to the set
unbalance current in one or more phases exceeds the set
detector 1 module sends the enabling signal to the Timer 1 module.
Timer 1
Once activated, the Timer 1 module activates the START output. Depending on the
value of the
to DT or IDMT. When the operation timer has reached the value of
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
B , Curve parameter C and Curve parameter E .
In a drop-off situation, that is, when a fault suddenly disappears before the
operation delay is exceeded, the Timer 1 reset state is activated. The functionality
of Timer 1 in the reset state depends on the combination of the
type and Reset delay time settings. When the DT characteristic is selected, the reset
timer runs until the set
REX640
Technical Manual
~+60°
~–120°
~–60°
~+120°
Phase angle of unbalance cur-
rent
~0°
~+180°
~–120°
~+60°
~+120°
~–60°
Operating curve type setting, the time characteristics are according
Reset delay time value is exceeded. When the IDMT curves
Protection functions
Phase B - Branch 1 or Phase B
- Branch 4
Phase B - Branch 2 or Phase B
- Branch 3
Phase C - Branch 1 or Phase C
- Branch 4
Phase C - Branch 2 or Phase C
- Branch 3
Element failure branch loca-
Figure 634
tion
Phase A - Branch 1 or Phase A
- Branch 4
Phase A - Branch 2 or Phase A
- Branch 3
Phase B - Branch 1 or Phase B
- Branch 4
Phase B - Branch 2 or Phase B
- Branch 3
Phase C - Branch 1 or Phase C
- Branch 4
Phase C - Branch 2 or Phase C
- Branch 3
Start value . If the compensated
Start value , the Level
Operate delay
Curve parameter A , Curve parameter
Operating curve
1135