ABB RELION REX640 Technical Manual page 1298

Protection related functions
The blinder in forward direction,
Resistive reach Fw K ˜
where:
P
expmax
U
expmin
K
The resistive boundary
Resistive reach Fw , but replace the maximum exporting active power P
the corresponding voltage U
P
impmax
The
reverse direction, these values are recommended to set the maximum possible load
angle when load active power arrives at top. A value bigger than 20° must be used.
1298
is the maximum exporting active power
is minimum phase-to-phase voltage when the exporting active power occurs
is a security factor to ensure that the setting of
minimal resistive load, with a recommended value 0.8.
Resistive reach Rv can be obtained in the same way as
and the corresponding voltage U
Max impedance angle and Min impedance angle are symmetric in forward and
Resistive reach Fw , can be calculated according to
2
U
expmin
P
expmax
with the maximum importing active power
expmin
.
impmin
1MRS759142 F
(Equation 313)
Resistive reach Fw less than
and
expmax
REX640
Technical Manual