ABB RELION RER670, Applications Manual, Page: 143 / 506

IMinOpPP : It is used to select the minimum operating current for the phase-to-
phase loops. Set this to 10% IB .
OpLoadEnch : This setting is used to select the load discrimination characteristic.
Set this to On .
RLd : It is used to set the resistive reach within the load impedance of load
discrimination characteristic. RLd can be calculated according to equation:
max
2
min
8 . 0
P
U
RLd

IECEQUATION15051 V1 EN-US
(Equation 18)
Where,
P
max
is the maximum exporting power = 2.5 times the rated power of 50MVA.
U
min
is the minimum voltage which can be taken as 90% of 110.0kV which is
equal to 99kV.
0.8 is security factor.
Therefore RLd = 0.8 (99.0)
2
/2.5 x 50.0 = 62.7 Ohm.
ArgLd : This is used to set the load angle determining the load impedance area of
the load discrimination characteristic. Set the parameter to the maximum possible
load angle at maximum possible load. Set this to 30 deg.
OpModetEnd1 : It is used to select the On/Off operation of the first stage timer
tEnd1 . Set this to On .
OpDirEnd1 : This is used to select the direction mode of end zone 1. Set this to
Forward .
tEnd1 : This is used to set time delay for the first stage remote backup. Set this
higher than zone 3 time delay of 0.7s plus additional delays provided. Set this to
the default 2.5s.
OpModetEnd2 : This is used to select the operation On/Off of the second stage
timer tEnd2 . Set this to On .
OpDirEnd2 : This is used to select the direction mode of the end zone 2. Set this to
Non-directional .
tEnd2 : This is used to set the time delay for the second stage trip. Set this after the
tEnd1 has operated. Since the tEnd1 is set to 2.5s, set it to 3.0s.
OpModeGenSt : This is used to select On/Off of zone timers start by general start
signal. Set this to On .
ZoneCharSym : This is used to set On/Off of the zone symmetry. Set this to
Symmetry .
1MRK 506 375-UEN A
Section 7
Impedance protection
Railway application RER670 2.2 IEC 137
Application manual