Sensor Inputs For Currents And Voltages - ABB Relion SMU615 Technical Manual

Section 3
Basic functions
3.7
52

Sensor inputs for currents and voltages

This chapter gives short examples on how to define the correct parameters for sensors.
Sensors have corrections factors, measured and verified by the sensor
manufacturer, to increase the measurement accuracy of primary
values. Correction factors are recommended to be set. Two types of
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
merging unit (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-6A480073-5C35-4319-8B38-402608D4C098 V2 EN
RSV
I
n
I
pr
f
n
K
r
In this example, the value is as calculated using the equation.
150 A
mV
150
×
80 A
= . 5 625
50 Hz
GUID-13DE42A0-29C0-4FE0-B00B-1215B37E3B7B V2 EN
With this information, the merging unit's Rogowski sensor settings can be set.
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
mV
Hz
1MRS758407 B
(Equation 1)
(Equation 2)
SMU615
Technical Manual