ABB RELION 620 Series Technical Manual page 855

1MRS757644 F
620 series
Technical Manual
Example values of positive-sequence impedances for typical medium voltage
overhead-lines are given in the following tables.
Table 812: Positive-sequence impedance values for typical 11 kV conductors, "Flat" tower
configuration assumed
Name
ACSR 50 SQ.mm
ACSR 500 SQ.mm
Table 813: Positive-sequence impedance values for typical 10/20 kV conductors, "Flat" tower
configuration assumed
Name
Al/Fe 36/6 Sparrow
Al/Fe 54/9 Raven
Al/Fe 85/14 Pigeon
Al/Fe 93/39 Imatra
Al/Fe 108/23 Vaasa
Al/Fe 305/39 Duck
Table 814: Positive-sequence impedance values for typical 33 kV conductors, "Flat" tower
configuration assumed
Name
ACSR 50 sq.mm
ACSR 100 sq.mm
ACSR 500 sq.mm
Zero-sequence impedance values
Location of earth faults requires both positive-sequence and zero-sequence
impedances. For short circuit faults, zero-sequence impedances are not required.
The positive-sequence impedance per unit values for the lines are typically known or
can easily be obtained from data sheets. The zero-sequence values are generally not as
easy to obtain as they depend on the actual installation conditions and configurations.
Sufficient accuracy can, however, be obtained with rather simple calculations using
the following equations, which apply per phase for symmetrically transposed three-
phase aluminium overhead lines without ground wires.
R [ 50 Hz ] R 1 0 14804 . [ /
≈ +
0
GUID-087D1F51-4C8C-4CF4-ACE5-9F43AF0DD3FC V1 EN
R [ 60 Hz ] R 1 0 17765 . [ /
≈ +
0
GUID-C33EC003-0DA2-4FFC-9496-586D7342DAF6 V1 EN
Protection related functions
R1 [Ω/km]
0.532
0.0725
R1 [Ω/km]
0.915
0.578
0.364
0.335
0.287
0.103
R1 [Ω/km]
0.529
0.394
0.0548
km ]
Ω
km ]
Ω
Section 5
X1 [Ω/km]
0.373
0.270
X1 [Ω/km]
0.383
0.368
0.354
0.344
0.344
0.314
X1 [Ω/km]
0.444
0.434
0.346
(Equation 166)
(Equation 167)
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