Calculated Analogue Channels - ABB REM 543 Technical Reference Manual

ABB Network Partner
4.1.5.3.
REM 543 Protection,
Monitoring and Control
The correction parameters/factors are calculated as follows:
Current transformers
Amplitude error at current I
(e = error in per cent)
Amplitude error at current 0.01 x I
(e = error in per cent)
Phase displacement error at current I
(e = error in degrees)
Phase displacement error at current 0.01 x I
(e = error in degrees)
Voltage transformers
Amplitude error at voltage U
(e = error in per cent)
Phase displacement error at voltage U
(e = error in degrees)
Rogowski coil
Amplitude error at the whole measuring range
(e = error in per cent)
Voltage divider
Amplitude error at the whole measuring range
(e = error in per cent)

Calculated analogue channels

The REM 543 machine terminal includes two virtual channels to obtain the neutral cur-
rent and residual voltage when sensors are used. Current sensors and voltage dividers
are directly connected to the machine terminal via coaxial cables and therefore a resid-
ual connection of the phase currents or an open-delta connection of the phase voltages
cannot be made. Both the amplitude and the phase angle are calculated for the virtual
channels.
Channel 11 is used to numerically derive the neutral current I
rents (I = I + I + I ).
0 1 2 3
Note! However, when sensitive earth-fault protection is needed, cable current trans-
formers are not recommended to be replaced with the numerically derived sum of phase
currents. Normally, an earth-fault setting below 10% of the rated value requires a cable
current transformer.
Channel 12 is used to derive the residual voltage U
U + U + U ). This channel is used instead of the open-delta connection when voltage
1 2 3
dividers are used to measure the phase voltages.
Technical Reference Manual
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Part 1, General
Amplitude correction factor 1
= 1 / ( 1+ e/100 )
Amplitude correction factor 2
= 1 / ( 1+ e/100 )
Phase displacement error 1 = - e
Phase displacement error 2 = - e
Amplitude correction factor
= 1 / ( 1+ e/100 )
Phase displacement error
= - e
Amplitude correction factor
= 1 / ( 1+ e/100 )
Amplitude correction factor
= 1 / ( 1+ e/100 )
from the three phase cur-
0
from the three phase voltages (U
0
=
0
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