Siemens SIPROTEC 7UT613 series Manual page 541

7UT613/63x Manual
C53000-G1176-C160-2
Mismatching factor for 7UT613/63x, (limited resolution of the measurement)
where:
I
= rated current of the protected object
nO
(in relation to the parameterised rated current)
U = parameterised rated current of the protected object
nO
I
= nominal device current
Nrelay
S = maximum (rated) power of the protected object
Nmax
(for transformers: side with the largest (rated) load)
Caution: If earth fault differential protection is used, the requirement for the phase
current transformer of the REF side is as follows:
≤ F
1
former remains /
8 Adap
Figure A-30 CT verification for Devices 7UT613/63x
The CB layout within the power station unit is not specified.
x" = sub-transient direct-axis reactance of the generator in p.u.
d
U = transformer short-circuit voltage HV - LV in %
k
= assumed with 0.1 Ω, (the consumption of the above devices is below
R
relay
0.1 VA)
A.4 Current Transformer Requirements
1
≤ 8)
≤ F ≤ 4, (for the starpoint trans-
/
4 Adap
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