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Annex Case studies MVDC economics
A. the
transmission distance increases within the
60 capacity the ±35 system MVDC
becomes increasingly cost-effective compared to
HVAC. Therefore, replacing a
single overhead transmission line (approximately
USD 846k/km) with two overhead distribution
lines (approximately USD 107k/km, excluding
converters,) offers cost advantage.
For loads greater than MVA lengths
exceeding km, KEPCO’s procedures call for
power supplied using 154 transmission
system instead the 22.
This recommendation based the supply
capacity and voltage drop considerations the
AC distribution line.
Figure A-3 MVDC replacement long-distance line scenario
Figure A-4 Long distance distribution economics based initial investment (left) and 20-year
operational NPV (right)
0
8
17
25
34
42
50
59
67
28 31
34 37
40
43 51
0
20
40
60
80
0 64
USD(M$)
FEEDER LENGTH (KM)
20-Year NPV NPV
DC NPV
0
7
14
20
27
34
41
48
54
14 28
0
10
20
30
40
50
60
0 64
USD(M$)
FEEDER LENGTH (KM)
Initial Investment Cost
AC Investment Cost
DC Investment Cost
.
As shown Figure A-4, MVDC has economic
advantage over HVAC cable lengths greater
than approximately km, based initial
investment costs. However, with ±35 DC
distribution, both the capacity and transmission
distance can exceed the alternative more
than factor two.9 distribution system. When 20-year operational NPV
is considered, the break-even distance increases
to approximately km.2 Long-distance supply
Second scenario: Replacement long-
distance transmission line with MVDC segment,
as shown Figure A-3
