ABB REL670 2.2 IEC Applications Manual page 440

Section 8
Impedance protection
434
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
UBase 20
= =
ZBase
SBase 200
EQUATION1969 V1 EN-US
= +
ZA Z transf ( ) Zsc network (
EQUATION1970 V1 EN-US
This corresponds to:
j 0.38
= =
ZA j 0.19 pu
2.0
EQUATION1971 V1 EN-US
Set ZA to 0.19
2
20
= = ×
ZB jX ' j 0.25
d
200
EQUATION1972 V2 EN-US
This corresponds to:
j 0.5
= =
ZB j 0.25 pu
2.0
EQUATION1973 V1 EN-US
Set ZB to 0.25
2
20
= = × =
ZC jX j 0.15
T
200
EQUATION1974 V1 EN-US
This corresponds to:
j 0.3
= =
ZC j 0.15 pu
2.0
EQUATION1975 V2 EN-US
2
=
2.0 ohm
2 2
20 20
= × +
) j 0.15 j
200 5000
= Ð °
0.19 90 pu
=
j 0.5 ohm
= Ð °
0.25 90 pu
j 0.3 ohm
= Ð
o
0.15 90 pu
1MRK 506 369-UEN B
=
j 0.38 ohm
Line distance protection REL670 2.2 IEC
Application manual
(Equation 434)
(Equation 435)
(Equation 436)
(Equation 437)
(Equation 438)
(Equation 439)
(Equation 440)