Table 91: Calculated voltages for different connection types
Voltage connection Phase-to-phase
voltages (Ph-Ph)
Phase-to-neutral
voltages (Ph-n)
Residual voltage Uo
3 × ph-n yes, calculated yes yes, calculated
3 × ph-n + Uo yes, calculated yes yes
2 × ph-n yes, calculated
1
yes, missing ph-n cal-
culated
1
no
2 × ph-n + Uo yes, calculated yes, missing ph-n cal-
culated
yes
3 × ph-ph yes yes, calculated
1
no
3 × ph-ph + Uo yes yes, calculated yes
2 × ph-ph yes, missing ph-ph
calculated
yes, calculated
1
no
2 × ph-ph + Uo yes, missing ph-ph
calculated
yes, calculated yes
3.12 Sensor inputs for currents and voltages
This chapter gives short examples on how to define the correct parameters for
sensor measurement interfaces.
Sensors can have correction factors, measured and verified by the sensor
manufacturer, to increase the measurement accuracy. Correction factors
are recommended to be set to the relay. Two types of correction factors
are available for voltage and current (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 and/or sensor routine test protocol. If the
correction factors are not available, contact the sensor manufacturer for
more information.
Figure 56: Example of ABB Rogowski current sensor KECA 80 D85 rating plate
Current (Rogowski) sensor setting example
In this example, an 80 A/0.150 V at 50 Hz (0.180 V at 60 Hz) sensor, such as
the example shown in
Figure 56
, is used in a 50 Hz electrical network. The
application has a 150 A nominal current (In) corresponding to the protected
object’s nominal current. The application nominal current is set to Rogowski
1
Uo assumed zero.
1MRS759142 F Basic functions
REX640
Technical Manual
157
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