X1FwZ3: This is used to set the forward positive sequence reactance reach for zone
3 in Ohm/p. This should be set to 120% of reactance of (Line 1 + Line 2).
Therefore, set X1FwZ3 to 1.2 x (50 +100) x 0.112 = 20.16 Ohm.
X1RvZ3
: Set this identical to X1FwZ3 which is 20.16 Ohm.
REoverRLZ3: This is used to provide zero sequence compensation for phase-to-
earth faults.
28.01
097.0
151.0
2
1
1
2
1
1
0
R
R
R
R
L
E
IECEQUATION15052 V1 EN-US (Equation 32)
Therefore, set this to 0.28.
XEoverXLZ3: This is used to provide zero sequence compensation for phase-to-
earth faults.
83.01
112.0
298.0
2
1
1
2
1
1
0
X
X
X
X
L
E
IECEQUATION15053 V1 EN-US (Equation 33)
Therefore, set this to 0.83.
RFPEFwZ3: This may be set identical to setting RFPEFwZ2 which is 40.13 Ohm.
RFPERvZ3: It is set identical to setting RFPEFwZ3 which is 40.13 Ohm.
RFPPFwZ3: This may be set identical to setting RFPEFwZ3 which is 40.13 Ohm.
RFPPRvZ3: It is set identical to setting RFPEFwZ3 which is 40.13 Ohm.
TimerSelZ3
: This is used for Zone timer selection mode of zone 3. Set this to
Timers separated.
OpModetPEZ3: Set this to On.
tPEZ3: Choose a time delay for zone 3 with a margin to assure selectivity to zone 2
of adjacent lines. A delay time difference of 0.4s between the zones is sufficient.
The time delay for zone 3 therefore can be set to 0.8s.
OpModetPPZ3: Set this to On.
tPPZ3: Set this identical to tPPZ3 = 0.8s.
Zones 4, 5 and 6 can be set on similar lines based on the
application.
1MRK 506 375-UEN A Section 7
Impedance protection
Railway application RER670 2.2 IEC 149
Application manual