ABB RELION RET670 Applications Manual page 480

Section 8
Impedance protection
474
With all phase voltages and phase currents available and fed to the protection IED, it is
recommended to set the MeasureMode to positive sequence.
The impedance settings are set in pu with ZBase as reference:
2
UBase 400
= =
ZBase
SBase 1000
EQUATION1960 V1 EN-US
= +
ZA Z line ( ) Zsc station (
EQUATION1961 V1 EN-US
This corresponds to:
+
2 j 52
= =
ZA 0.0125
160
EQUATION1962 V1 EN-US
Set ZA to 0.32.
= =
ZB Zsc station ( 1)
EQUATION1963 V1 EN-US
This corresponds to:
j 32
= =
ZB j 0.20 pu
160
EQUATION1964 V1 EN-US
Set ZB to 0.2
This corresponds to:
+
2 j 20
= =
ZC 0.0125
160
EQUATION1966 V1 EN-US
Set ZC to 0.13 and AnglePhi to 88°
2
=
160 ohm
400
= + +
2) 2 j 20 j
5000
+ = Ð °
j 0.325 pu 0.325 88
2
400
=
j j 32 ohm
5000
= Ð °
0.20 90 pu
+ = Ð °
j 0.125 pu 0.126 84
1MRK 504 163-UUS A
2
= +
2 j 52 ohm
pu
pu
Transformer protection RET670 2.2 ANSI
Application manual
(Equation 395)
(Equation 396)
(Equation 397)
(Equation 398)
(Equation 399)
(Equation 400)