IEEE Power & Energy Magazine - July/August 2019 - 26

for industrial purposes, 164.5 TWh for commercial applications, and 66.5 TWh for residential use. The maximum
demand reached 92.5 GW in 2018 and is forecast to grow
and reach 110 GW in 2030, according to the eighth longterm electricity supply and demand plan published by
the Ministry of Trade, Industry, and Energy. The total
installed generation capacity in the Korean power system
is currently 119 GW.
Table 1 shows the transmission, substation, and distribution facilities in the Republic of Korea from 1992 through
2017. As is shown, the number of 345- and 154-kV transmission and substation facilities has increased, but the number
of 66-kV transmission facilities has decreased. Since 1990,
these facilities have been intentionally retired to improve
transmission efficiency.
KEPCO has established a new voltage level (70 kV)
to accommodate increasing amounts of RESs in accordance with its long-term electricity supply and demand
plan. The first 70-kV substation will be installed in 2022
and reflect a modular design. While it typically takes four
years to install a conventional substation, strategically
locating modular substations would likely expedite the
process significantly.

Outlook for Korea's Efforts in
Smart Substation Development
Development of Digital Substations
and Communication Network
After the publication of IEC 61850 in 2004, a task force to
promote digital substations was created. Table 2 is an overall road map for the implementation of the smart substation.
After several pilot projects, the first 154-kV digital substation was installed in 2013. A total of 32 digital substations
were installed in 2018, and 740 more are expected to be
installed by 2034, which includes the digitalization of existing substations. Figure 1 shows the status and future installation plans for digital substations in the Republic of Korea.
As the number of digital substations increases annually, the
proportion of total digital substations is expected to reach
83% in 2034.
Smart substation features developed during the preparation stage for the application of IEC 61850 to establish communication networks for digital substations included the
following: substation virtual servers, substation gateways,
IED explorer (software that performs IEC 61850 client simulator for the testing of IEC 61850-based IEDs), a digital

table 1. Transmission, substation, and distribution facilities in the Republic of Korea.
Division
Transmission
facilities (C-km)

Substation facilities
(MVA)

Number of
substations

Distribution facilities

1992

1997

2002

2007

2012

2017

765 kV

-

-

662

755

835

1,019

345 kV

5,259

6,442

7,496

8,284

8,770

9,746

154 kV

11,631

15,097

18,144

19,917

21,578

22,831

66 kV

3,579

2,513

1,402

338

208

128

Total

20,469

24,052

27,704

29,294

31,391

33,724

765 kV

-

-

7,110

23,114

29,116

38,116

345 kV

26,339

46,009

69,078

95,279

115,598

131,880

154 kV

32,982

58,706

83,364

109,268

126,143

141,538

66 kV

2,103

1,813

1,073

454

312

240

22 kV

508

308

213

134

78

94

Total

61,932

61,932

160,838

228,249

271,247

311,868

765 kV

-

-

3

5

5

7

345 kV

20

36

69

81

68

112

154 kV

223

335

472

571

636

713

66 kV

74

48

20

6

3

3

22 kV

14

8

10

6

3

4

Total

331

427

574

669

715

839

Line (C-km)

255,340

326,506

366,983

401,485

442,641

481,365

Transformer
(MVA)

24,072

39,596

71,977

92,963

104,081

114,236

C-km: Circuit kilometer.
26

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