costs and decreased system losses. This connection would improve the voltage stability in the distribution system. The G-platform can also be interconnected in parallel with existing substations, especially when the existing substation does not have any additional space for expansion. The advantages of the G-platform are summarized as follows: ✔ The installation is fast, simple, and flexible because of the modular design and the capacity upgrade, and installation location change is easy. ✔ At strategic locations, it is expected to face minimal public opposition because of its compact design. ✔ Because of the ESS, it can act as a virtual power plant and minimize the adverse effects of variations in generation output from renewables. This means that a DER with a G-platform can be used as a dispatchable generator. ✔ In the event of a failure of the existing substation, it can be installed quickly to prevent a long outage period. KEPCO is developing a standard specification for the installation of the G-platform and the technologies for table 4. Existing and planned HVdc and FACTS substations in the Republic of Korea (as of March 2019). Type Year Capacity Location Status HVdc 1998 2019 (refurbishment) 300 MW Jeju HVdc No. 1 Under refurbishment UPFC 2003 80 MVA Kangjin Substation In operation STATCOM 2009 ±100 MVar Migum Substation In operation SVC 2010 ±200 MVar Dongseoul Substation In operation STATCOM 2010 ±50 MVar Sinjeju Substation In operation STATCOM 2010 ±50 MVar Halla Substation In operation SVC 2012 ±200 MVar Sinpaju Substation In operation HVdc 2014 400 MW Jeju HVdc No. 2 In operation STATCOM 2014 ±100 MVar Sinsungnam Substation In operation STATCOM 2017 ±400 MVar Sinyoungju Substation In operation STATCOM 2017 ±400 MVar Sinchungju Substation In operation STATCOM 2018 ±200 MVar Sinbupyung Substation Under installation SVC 2018 -225 ~ +675 MVar Sinjaechun Substation In operation TCSC 2019 555 MVar × 2 Sinyoungju Substation Under installation TCSC 2019 595 MVar × 2 Sinjaechun Substation Under installation STATCOM 2018 ±300 MVar Godeok Substation Under installation STATCOM 2019 ±300 MVar Singapyoung Substation Under planning STATCOM 2022 ±300 MVar Uijeongbu Substation Under planning STATCOM 2021 ±300 MVar Sinhanul Substation No. 1 Under planning STATCOM 2022 ±300 MVar Sinhanul Substation No. 2 Under planning HVdc 2019 1.5 GW Bukdangjin-Godeok No. 1 Under installation HVdc 2020 200 MW Jeju HVdc No. 3 Under installation HVdc 2021 1.5 GW Bukdangjin-Godeok No. 2 Under installation HVdc 2021 4 GW Sinhanul-Singapyoung No. 1 Under planning BTB 2021 200 MW Yangju Substation Under planning HVdc 2022 4 GW Sinhanul-Singapyoung No. 2 Under planning HVdc 2023 2 GW West Coast Offshore Wind Connection Under planning TCSC: thyristor-controlled series capacitor; UPFC: unified power flow controller; SVC: static VAR compensator 32 ieee power & energy magazine july/august 2019