ABB RER670 Applications Manual page 150

Section 7
Impedance protection
144
UBase: Sets the base voltage in kV. This is 110.0kV.
Operation: Sets the protection to On/Off. Set this to On.
System Earthing: It is used to select the type of system earthing. Select the
Compensated.
LineAng: Set it to 50 deg.
IMinOpPE: It is used to select the minimum operating current for the phase-to-
earth loops. Set this to 10% IB.
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:
2
U
RLd 
min
0 8 .
P
max
IECEQUATION15051 V1 EN-US
Where,
P is the maximum exporting power = 2.5 times the rated power of 50MVA.
max
U is the minimum voltage which can be taken as 90% of 110.0kV which is
min
equal to 99kV.
0.8 is security factor.
Therefore RLd = 0.8 (99.0)
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.
2
/2.5 x 50.0 = 62.7 Ohm.
1MRK 506 375-UEN A
(Equation 25)
Railway application RER670 2.2 IEC
Application manual