ABB RELION REX640 Technical Manual page 629

1MRS759142 F
Figure 357: Illustration of fault current magnitude and phase-to-phase voltage
magnitude during a cross-country fault as a function of fault resistance. Note that
fault resistance equals the average of fault resistances R
= 2.2 ohm, R
Setting value
phase-to-phase value as reference.
Fulfilment of either
detection condition in the network. The cross-country fault is indicated by
activating the XC_FLT output.
REX640
Technical Manual
= 0.2 ohm.
k
XC stage PP V Val is given in per unit format with system nominal
Equation 132
During detected cross-country fault, the "EF current based" or "Touch
voltage based" operation of IFPTOC is blocked.
Equation 135
or declares cross-county fault
Protection functions
and R . U = 20 kV, X
F1 F2 n_PP k
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