Hitachi Relion 670 Series Applications Manual page 124

Section 7
Impedance protection
Parameter
Line length B-C
Positive sequence impedance of line
Zero sequence impedance of line
Arc resistance
Tower footing resistance
General
Common base IED values for primary current (IBase) and primary voltage (UBase) are set in a
Global base values for settings function GBASVAL.
GlobalBaseSel: To select a GBASVAL function for reference of base values.
IBase: Sets the base current in primary ampere. This is 50 MVA/110 kV = 454.54 A.
UBase: Sets the base voltage in kV. This is 110.0 kV.
Operation: Sets the protection to On/Off. Set this to On.
System Earthing: To select the type of system earthing. Select the Compensated.
LineAng: Set it to 50 deg.
IMinOpPE: To select the minimum operating current for the phase-to-earth loops. Set this to 10% IB.
IMinOpPP: To select the minimum operating current for the phase-to-phase loops. Set this to 10% IB.
OpLoadEnch: To select the load discrimination characteristic. Set this to On.
RLd: To set the resistive reach within the load impedance of load discrimination characteristic. RLd
can be calculated according to equation:
RLd 
IECEQUATION15051 V1 EN-US
Where,
P is the maximum exporting power = 2.5 times the rated power of 50 MVA.
max
U is the minimum voltage which can be taken as 90% of 110.0 kV which is equal to 99 kV.
min
0.8 is security factor.
Therefore RLd = 0.8 (99.0)
ArgLd: 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: To select the On/Off operation of the first stage timer tEnd1. Set this to On.
OpDirEnd1: To select the direction mode of end zone 1. Set this to Forward.
tEnd1: To set time delay for the first stage remote backup. Set this higher than zone 3 time delay of
0.7 s plus additional delays provided. Set this to the default 2.5 s.
OpModetEnd2: To select the operation On/Off of the second stage timer tEnd2. Set this to On.
118
2
U
min
0 8 .
P
max
2
/2.5 x 50.0 = 62.7 Ohm.
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Value
100 km
0.097 + j0.112 Ohm/km = 0.1481 ∟ 49.3 deg Ohm/km
0.151 + j0.298 Ohm/km = 0.334 ∟ 63.13 degOhm/km
2 Ohm
10 Ohm
Railway application RER670
1MRK506375-UEN Rev. N
GUID-0539986A-C449-4E29-9067-ACF82F94995C v4
(Equation 18)
Application manual