IEEE Power & Energy Magazine - July/August 2019 - 30

High-Efficiency
Transformer

Ecofriendly
Compact GISs

ESS-Active Power Compensation
Charge Discharge

PCS

PMS

BMS

Charge

Discharge
Battery

BESS

FACTS-ac Voltage
Regulation

RES Power
Compensated Power

STATCOM
TCR TSC
TSR

Expected Number of the
Overcapacity Substations

figure 4. The configuration of the G-platform. PCS: power conditioning system; BESS: battery ESS; BMS: battery management system; PMS: power management system; TCR: thyristor-controlled reactor; TSR: thyristor-switched reactor; TSC:
thyristor-switched capacitor; STATCOM: static synchronous compensator.
25
20

15
10
5
0

8
5

7
4

0~10 MW 10~20 MW 20~30 MW 30~40 MW 40 MW ~

The Amount of Excess Capacity of the Overcapacity Substations

figure 5. The preliminary study results for the future
renewable generation installation (August 2016). The excess
capacity of 76.5% of overcapacity substations is lower than
30 MW.

have been manufactured by several companies across the
globe. MarketsandMarkets, a company that provides market analysis reports of segmentation, trends, share, and
forecasts, forecasted the growth of the modular substation
market from US$10.782 billion in 2015 to US$16.477
billion in 2020. While there was no historical need and
market for modular substations in the Republic of Korea,
the government has adopted this technology to achieve
its RE vision. Such substations are planned to interconnect RESs, which are called modular green platforms (G-platforms).
30

ieee power & energy magazine

The design of G-platforms will be optimized to integrate
RESs and be environmentally friendly. The G-platform will
increase the capacity of the substation and also minimize
the adverse effects of intermittent RE and volatility through
communication between the G-platform and the RESs. Figure 4 illustrates the concept of the G-platform, which is in a
container and can be configured with a 170-kV GIS, a 23-kV
GIS, a 154-kV/22.9-kV transformer, and connections for an
energy storage system (ESS) and a flexible ac transmission
system (FACTS). ESSs and FACTSs can be installed as
needed to improve the power quality and stability of the grid
with a high penetration of DERs.
Capacity Determination of the G-Platform

Figure 5 shows results of a preliminary study conducted
in August 2016 for renewable generation installations that
were planned for 2018. Results showed 47 of the 698 substations with 154-kV/22.9-kV transformers were going to be
over capacity in 2018 due to RES connections. The study
results also showed that 97 substations would exceed 50%
of their capacity, of which 63 substations would exceed 70%.
The number of overcapacity substations would gradually
increase with the addition of RESs, as was anticipated in
the near future. Given the difficulties of increasing the hosting capacity of the RESs, the urgent need for G-platforms
became apparent. Figure 5 shows that under 30 MW of excess
capacity is available in 76.5% ^6(23 + 8 + 5) /47@ # 100%h of
july/august 2019

IEEE Power & Energy Magazine - July/August 2019

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