Figure 31: Single Line Diagram - ABB UniGear Series Engineering Manual

E NG INEE R ING
Primary current
Setting example
In this example, an 80 A / 0.150 V at 50 Hz sensor is used and the application has a 1 000 A
nominal current (I

Figure 31: Single line diagram

When defining another primary value for the sensor, also the nominal voltage should be rede-
fined to maintain the same transformation ratio. However, the setting in the protection relay
Rated Secondary Value
(
for both 50 Hz and 60 Hz nominal frequency.
���� ������
������ =
RSV
I
n
I
pr
K
r
f
n
In this example, the value is as calculated using the equation.
1000 �� 80 ��
������ =
1V LG 5 000 07 E
).
n
) is not in V but in mV / Hz, which makes the same setting value valid
⁄
× ����
����
Rated secondary value in mV / Hz
Application nominal current
Sensor-rated nominal current
Sensor-rated voltage at the rated current in mV
Network nominal frequency
⁄
× 150 ����
50 ����
����
= 37.5
����
S E NS O R S
2 7