ABB RELION REX640 Technical Manual page 153

1MRS759142 C
REX640
Technical Manual
correction factors are available for voltage and Rogowski sensors.
The Amplitude correction factor is named Amplitude corr. A(B/C) and
Angle correction factor is named Angle corr A(B/C). These correction
factors can be found on the Sensor's rating plate. If the correction
factors are not available, contact the sensor manufacturer for more
information.
Rogowski sensor setting example
In this example, an 80 A/0.150 V at 50 Hz sensor is used and the application has a 150
A nominal current (In). As the Rogowski sensor is linear and does not saturate, the 80
A/0.150 V at 50 Hz sensor also works as a 150 A/0.28125 V at 50 Hz sensor. When
defining another primary value for the sensor, also the nominal voltage has to be
redefined to maintain the same transformation ratio. However, the setting in the
protection relay (Rated Secondary Value) is not in V but in mV/Hz, which makes the
same setting value valid for both 50 and 60 Hz nominal frequency.
I
n
K
⋅
r
I
pr
RSV
=
f
n
GUID-442AEFFC-D1E8-41ED-8063-063E67E090D7 V1 EN
RSV
I
n
I
pr
f
n
K
r
In this example, the value is as calculated using the equation.
A
150
150 mV
⋅
mV
A
80
= . 5 625
Hz
50
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With this information, the protection relay's Rogowski sensor settings can be set.
Table 73: Example setting values for rogowski sensor
Setting
Primary current
Rated secondary value
If the ratio of the application nominal current I
becomes higher, and the rated secondary value needs to be set higher than 46.875 mV/
Rated Secondary Value in mV/Hz
Application nominal current
Sensor-rated primary current
Network nominal frequency
Sensor-rated voltage at the rated current in mV
Hz
Value
150 A
5.625 mV/Hz
n
Section 3
Basic functions
and sensor-rated primary current I
(Equation 1)
(Equation 2)
pr
147