Siemens 7SC80 - Class Conversion; D.2 Class Conversion

Class conversion
Table D-1 Conversion into other classes
British Standard BS 3938
ANSI/IEEE C 57.13, class C
Ι
sN
= 5 A (typical value)
IEC 60044-6 (transient
response), class TPS
Classes TPX, TPY, TPZ
K≈ 1
K
SSC
≈ K
ALF
Calculation see D.1 Accuracy limiting factors with: K
SSC
≈ K
ALF
T
P
depending on power system and specified closing sequence
with
V
k
Knee-point voltage
R
Ct
Internal burden resistance
R
BN
Nominal burden resistance
Ι
sNom
Secondary nominal transformer current
K
ALF
Rated accuracy limiting factor
V
s.t.max
Sec. terminal voltage at 20 I
pNom
V
al
Sec. magnetization limit voltage
K Dimensioning factor
K
SSC
Factor symmetr. Rated fault current
T
P
Primary time constant
D.2
Current Transformer Requirements
D.2 Class conversion
SIPROTEC Compact, 7SC80, Manual 607
E50417-G1140-C486-A8, Edition 07.2017