Functions
2.19 Impedance Protection (ANSI 21)
SIPROTEC, 7UM62, Manual
C53000-G1176-C149-7, Release date 03.2010
160
Example:
Transformer data:
u
SC
= 7 %
S
N
= 5.3 MVA
U
N
= 6.3 kV
Transformation ratios:
Current transformer ratio = 500 A / 1 A
This results for a 70 % reach for zone 1 in:
The following secondary side setting value of zone 1 results at address 3306 ZONE Z1:
Note: The following ratio would result from the connection of a 5 A device to a 5 A transformer:
Likewise the following primary reactance results for a 100 % reach for zone 2:
The following secondary side setting value of zone 2 results at address 3310 ZONE Z2: