Siemens siprotec SJ62, User Manual

Page: 57 / 715

2 Functions
55
SIPROTEC 4, 7SJ62/63/64 Handbuch
C53000-G1140-C147-A, Edition 07.2015
Calculation Example:
20 kV overhead line 120 mm
2
with the following data:
R
1
/s = 0.39
Ω
/mile Positive sequence resistance
X
1
/s = 0.58
Ω
/mile Positive sequence reactance
R
0
/s = 1.42
Ω
/mile Zero sequence resistance
X
0
/s = 2.03
Ω
/mile Zero sequence reactance
For ground impedance ratios, the following result:
These values are set at addresses
1103
and
1104
respectively.
Reactance Setting
(only for Fault Lo-
cation) The reactance setting must only be entered if using the line fault location function. The
reactance setting enables the protective relay to indicate the fault location in terms of
distance.
The reactance value X' is entered as a value
x'
at address
1105
in
Ω
per mile if set
to distance unit
Miles
(address
215
, see Section 2.1.3.2 "Distance Unit") , or at
address
1106
in
Ω
per kilometer if set to distance unit
km
. If the setting of address
215
is modified after entry of a reactance value at address
1105
or
1106
, the reactance
value must be modified and reentered accordingly.
When using the PC and DIGSI for configuration, these values can also be entered as
primary values. The following conversion to secondary values is then not relevant.
For calculation of primary values in terms of secondary values the following applies in
general:
Likewise, the following goes for the reactance setting of a line:
with
N
CTR
— Current transformer ratio
N
VTR
— Voltage transformer ratio