ABB REG670 - Technical Data

blocks with the text inside: 2nd Harmonic; Wave block and 5th Harmonic). If
there is less harmonic pollution. than allowed by the settings I2/I1Ratio, and I5/
I1Ratio, (then the outputs from the blocks 2nd harmonic and 5th harmonic is 0)
then it is assumed that a minor simultaneous internal fault must have occurred.
Only under these conditions a trip command is allowed (the signal TRIPRESL1
is = 1). The cross-block logic scheme is automatically applied under such
circumstances. (This means that the cross block signals from the other two phases
L2 and L3 is not activated to obtain a trip on the TRIPRESL1 output signal in
figure
39)
6. All start and blocking conditions are available as phase segregated as well as
common (that is three-phase) signals.
a>b
a
b
&
t
tAlarm Delay
IDALARM
a>b
a
b
a>b
a
b
IDL1 MAG
I Diff Alarm
I Diff Alarm
I Diff Alarm
IDL2 MAG
IDL3 MAG
en06000546.vsd
IEC06000546 V1 EN
Figure 43: Differential current alarm logic
6.1.8 Technical data
Table 48: T2WPDIF, T3WPDIF technical data
Function
Range or value Accuracy
Operating characteristic Adaptable ±1.0% of Ir at I ≤ Ir
±1.0% of I at I > Ir
Reset ratio > 90% -
Unrestrained differential current limit (100-5000)% of IBase on high voltage
winding
±1.0% of set value
Minimum pickup (5-60)% of IBase ±1.0% of Ir
Second harmonic blocking (5.0-100.0)% of fundamental
differential current
±1.0% of I
r
Note: fundamental
magnitude =
100% of I
r
Fifth harmonic blocking
(5.0-100.0)% of fundamental
differential current
±5.0% of I
r
Note: fundamental
magnitude =
100% of I
r
Table continues on next page
Section 6 1MRK502052-UEN B
Differential protection
140
Technical manual