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

D.2

Class conversion

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

D.2 Class conversion

with: K ≈ K
SSC ALF
pNom
607