ABB REL670 2.2 IEC, Applications Manual

Page: 440 / 908

Short circuit power from the external network without infeed from the protected
line: 5000 MVA (assumed to a pure reactance).
We have all phase voltages and phase currents available and fed to the protection
IED. Therefore it is recommended to set the
MeasureMode to positive sequence.
The impedance settings are set in pu with ZBase as reference:
2 2
20
2.0
200
UBase
ZBase ohm
SBase
= = =
EQUATION1969 V1 EN-US
(Equation 434)
2 2
20 20
( ) ( ) 0.15 0.38
200 5000
ZA Z transf Zsc network j j j ohm
= + = × + =
EQUATION1970 V1 EN-US
(Equation 435)
This corresponds to:
0.38
0.19 0.19 90
2.0
j
ZA j pu pu
= = = Ð °
EQUATION1971 V1 EN-US
(Equation 436)
Set ZA to 0.19
2
20
' 0.25 0.5
200
d
ZB jX j j ohm
= = × =
EQUATION1972 V2 EN-US
(Equation 437)
This corresponds to:
0.5
0.25 0.25 90
2.0
j
ZB j pu pu
= = = Ð °
EQUATION1973 V1 EN-US
(Equation 438)
Set ZB to 0.25
2
20
0.15 0.3
200
T
ZC jX j j ohm
= = × =
EQUATION1974 V1 EN-US
(Equation 439)
This corresponds to:
0.3
0.15 0.15 90
2.0
j
ZC j pu pu
= = = Ð o
EQUATION1975 V2 EN-US
(Equation 440)
Section 8
1MRK 506 369-UEN B
Impedance protection
434 Line distance protection REL670 2.2 IEC
Application manual