ABB REL650 Applications Manual page 165

1MRK 506 334-UUS A
Application manual
GlobalBaseSel: Selects the global base value group used by the function to define (IBase),
(VBase) and (SBase).
E
A
d
= const
A
A
Z
SA
~
R
ANSI99001019 V1 EN
Figure 76: Protected power line as part of a two-machine system
Reduce the power system with protected power line into equivalent two-machine system
with positive sequence source impedances Z
end bus B. Observe a fact that these impedances can not be directly calculated from the
maximum three-phase short circuit currents for faults on the corresponding busbar. It is
necessary to consider separate contributions of different connected circuits.
The required data is as follows:
=
V 400 kV
r
EQUATION1728 V1 EN
=
V 380 kV
min
EQUATION1729 V1 EN
=
f 60 Hz
n
EQUATION1730 V1 EN
400
=
V kV
p
3
EQUATION1731 V1 EN
0.115
=
V kV
s
3
EQUATION1732 V1 EN
=
I 1200 A
p
EQUATION1326 V1 EN
Table continues on next page
Impedance protection
B
Z
L
behind the IED and Z
SA
Rated system voltage
Minimum expected system voltage under critical system
conditions
Rated system frequency
Rated primary voltage of voltage protection transformers used
Rated secondary voltage of voltage instrument transformers used
Rated primary current of current protection transformers used
Section 6
E
B
d
= f(t)
B
Z
SB
~
99001019_ansi.vsd
behind the remote
SB
159