For loads greater than MVA lengths
exceeding km, KEPCO’s procedures call for
power supplied using 154 transmission
system instead the 22. However, with ±35 DC
distribution, both the capacity and transmission
distance can exceed the alternative more
than factor two.
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
. the
transmission distance increases within the
60 capacity the ±35 system MVDC
becomes increasingly cost-effective compared to
HVAC.72
Annex Case studies MVDC economics
A.9 distribution system.
As shown Figure A-4, MVDC has economic
advantage over HVAC cable lengths greater
than approximately km, based initial
investment costs. 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. When 20-year operational NPV
is considered, the break-even distance increases
to approximately km.
This recommendation based the supply
capacity and voltage drop considerations the
AC distribution line.2 Long-distance supply
Second scenario: Replacement long-
distance transmission line with MVDC segment,
as shown Figure A-3
