ABB RED615 - Signals

The required knee-point voltage can be calculated using Equation 61.
U
k
= 2 · ( 4620 A / 1000 ) · ( 15.3 + 1.46 ) ≈ 155 V.
The value 155 V is lower than the value 323 V, which means that the value of U
k
is
high enough.
As mentioned earlier, I
m
= 0.5 · I
e
gives a realistic value for I
prim
in
Equation 64. If
I
u
= 0 and I
rs
= m · 0.5 · I
e
, the value for the sensitivity is:
I
prim
= n · m · I
e
= 1000 · 4 · 0.012 A = 48 A ( ≈ 6 % x I
n
).
I
rs
= 4 · 0.5 · 0.012 A = 0.024 A.
The setting value can be calculated with:
Operate value
I
I
A
A
rs
CT n
=








=






≈
_
.
. %
2
0 024
1
2 4
GUID-3873DFF7-8FB3-42B1-BF99-CE7D9D141F55 V1 EN
The resistance of the stabilizing resistor can now be calculated:
R
s
= U
s
/ I
rs
= 78 V / (2 · I
e
) = 78 V / (2 · 0.012 A) = 3250 Ω.
Example 2b
In this example, I
rs
= 4 x 12 mA = 48 mA and I
u
= 30 mA. This results in the sensitivity:
I
prim
= n · ( I
rs
+ I
u
+ m · I
m
) = 1000 · (48 + 30 + 24) mA = 102 A
The setting value can be calculated with:
Operate value
I
I
A
A
rs
CT n
=








=






≈
_
.
. %
2
0 048
1
4 8
GUID-4373B1E0-46AB-401A-A76A-AD97B850D079 V1 EN
The resistance of the stabilizing resistor is now:
R
s
= U
s
/ I
rs
= 78 V / 48 mA ≈ 1630 Ω
In this example, the relay is of such a type that the stabilizing resistor can be
chosen freely.
4.3.4.9 Signals
Table 352: HREFPDIF Input signals
Name
Type Default Description
IDo SIGNAL 0 Differential current
BLOCK BOOLEAN 0=False Block signal for activating the blocking mode
Section 4 1YHT530004D05 D
Protection functions
444 615 series
Technical Manual