Table 52: Definition of long lines
Line category
Vn Vn
110 kV 500 kV
Long lines 45-60 miles 200-250 miles
Very long lines >60 miles >250 miles
The possibility in IED to set resistive and reactive reach independent for positive and
zero sequence fault loops and individual fault resistance settings for phase-to-phase
and phase-to-ground fault together with load encroachment algorithm improves the
possibility to detect high resistive faults at the same time as the security is improved
(risk for unwanted trip due to load encroachment is eliminated), as shown in figure 63.
en05000220_ansi.vsd
R
Zm
LdAngle
LdAngle
LdAngle
LdAngle
RLdFwdRLdRev
ZL
ANSI05000220 V1 EN
Figure 63: Characteristic for zone measurement for long line with load
encroachment activated
Parallel line application with mutual coupling
General
Introduction of parallel lines in the network is increasing due to difficulties to get
necessary area for new lines.
Section 3 1MRK504116-UUS C
IED application
194
Application manual
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