IEEE Power & Energy Magazine - July/August 2019 - 29

Substation 1
K-PQMS

Feeders

PQM
Server

Real-Time
Data
PQM
Protocol

LMAS
Event Data

LoadModeling
Results

TCP/IP

LMAS HMI

Display System Condition
Display LMAS Results

Substation 2

Feeders

PQM
Server

Real-Time Power Quality Data
(Time, V, I, Harmonic)

Event Data
(Interruption, Sag Data)
Apply Load Modeling Algorithm
Interruption
Sag

figure 3. The data flow of the LMAS of KEPCO. PQM: power quality meter.

of the LMAS. Whenever an event (e.g., a transmission line Increment of DERs and the Emergence
fault) occurs in the power system, the metering infrastruc- of a Modular Green Substation
ture of each substation measures it so it is transferred to the The Korean government aims to increase the proportion of
central KEPCO PQMS (K-PQMS). The K-PQMS builds a RESs to more than 20% of total generation by 2030. This
database that includes time, voltage, current, frequency, would require approximately 60 GW of RE facilities (Table 3).
harmonics, and flicker data and then selects suitable data To meet this goal, a government policy that promises interfor load modeling based on the predefined decision crite- connection of RESs under 1 MW has been announced,
ria. The selected data are transferred to the LMAS server, the Guarantees Interconnection of Renewables policy.
and the load models for the corresponding buses are devel- A large capacity of renewables is expected to be conoped. This entire process is completed automatically, and nected in the Korean power grid shortly. Remotely
the results are displayed on the LMAS HMI.
located DERs on long distribution lines, however, could
With the expansion of smart substations as well as cause power quality issues and adversely affect the voltAMIs to provide quality data on system states, more accu- age stability of the distribution network. Location and
rate and high-quality grid data will be obtained. Thus, a size uncertainties in future renewable installations also
plan was established to build a comprehensive online load- make it difficult to screen and confirm suitable locations
modeling infrastructure based on an LMAS, to include for interconnections and perform timely grid reinforcethe following:
ment studies. In addition, the high penetration of DERs
✔ event-driven online load modeling based on state esti- could threaten the frequency and voltage stability of the
mation data from the energy management system and entire power system. Installing modular substations is
one option to address these issues and increase DER
data from substations
✔ load-model database construction and analysis for de- hosting capacity.
veloping the representative model by season and time
✔ a real-time validation of the representative models Modular Green Substation (G-Platform)
through continuous monitoring at the smart substation
Modular or mobile substations are not new, but they have not
✔ the continuous validation and updating of the rep- yet been installed in the Republic of Korea. These substations
resentative load models
through big data analysis
table 3. Propects for RE growth in the Republic of Korea (eighth electrical
power supply and demand plan, December 2017).
and defining the representative model by season
2017
2022
2026
2030
and time.
Generation
11.3 (9.7%)
23.3 (16.4%)
38.8 (25.4%)
58.5 (33.7%)
The aforementioned online load
capacity (GW)
modeling should improve the reliGeneration
34.4 (6.2%)
58.3 (9.6%)
89.5 (14.4%)
125.8 (20%)
ability of the results from the power
amount (TWh)
system analysis.
july/august 2019

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