Solidly Earthed Systems - ABB RER670 Applications Manual

1MRK 506 375-UEN A
7.2.3.2
Railway application RER670 2.2 IEC
Application manual

Solidly earthed systems

Example in Figure 43 illustrates how the distance protection ZRWPDIS protects a
110kV overhead transmission line. The earthing considered is solidly earthed
system.
Out of the six distance protection zones, only the zone 1, zone 2 and zone 3 are
considered in this example. Zones 4, 5 and 6 can be set on similar lines depending
on the application they are being used.
All the settings for impedance are in Ohms Primary.
A
Line 1
Z<
IEC15000385 V1 EN-US
Figure 43: Considered single line diagram
Table 16: System Data
Parameter
System Voltage
System Frequency
Full load
Short time maximum Power
Minimum operating voltage
PT Ratio
CT Ratio
Line length A-B
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: It is used to select a GBASVAL function for reference of base
values.
IBase: Sets the base current in primary ampere. This is 50MVA/110kV = 454.54A.
Impedance protection
B
Line 2
Value
110kV
16.7Hz
50MVA
250% of Full load
90% of rated voltage
110kV/110V
600/1A
50km
100km
0.097 + j0.112 Ohm/km = 0.1481 ∟ 49.3°
Ohm/km
0.151 + j0.298 Ohm/km = 0.334 ∟ 63.13°
Ohm/km
2 Ohm
10 Ohm
Section 7
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