Inertia-Free Stand-Alone Microgrid - Part I: Analysis on Synchronized GPS Time-Based Control and Operation

Soo Hyoung Lee, Donghee Choi, Jung Wook Park

Research output: Contribution to journalArticlepeer-review

6 Citations (Scopus)


The inertia-free stand-alone (IFSA) microgrid is the new small power grid without synchronous generators equipped in conventional power systems. In other words, this system has the only converter-based generators (CBGs) based on energy storage devices and renewable energies. Therefore, it requires a new CBG control to provide strong voltage reference for the CBGs connected to the point of common coupling (PCC). This is because the IFSA microgrid is subject to a weak system such that it cannot maintain its rated frequency and/or bus voltage with the conventional real and reactive power controllers, which usually get their references from the PCC. This paper proposes the innovative conceptual approach for distributed coordination in the IFSA microgrid by applying the synchronized global positioning system time to the CBGs. Moreover, it is verified that the proposed physical structure of the IFSA microgrid makes it possible for all CBGs to share the real and reactive powers effectively. As the result, the proposed CBG control can provide the robustness, which is strongly required in the IFSA microgrid, based on timely outage management and restoration process. Several case studies are carried out with the microgrid of 36 MW to verify the effectiveness of the proposed CBG controller. The simulation and hardware-in-the loop tests are carried out using the power system computer-aided design/electromagnetic transient design and control (PSCAD/EMTDC) and the real-time digital power system simulator (RTDS), respectively.

Original languageEnglish
Article number8364573
Pages (from-to)4048-4059
Number of pages12
JournalIEEE Transactions on Industry Applications
Issue number5
Publication statusPublished - 2018 Sep 1

Bibliographical note

Funding Information:
Manuscript received July 24, 2017; revised January 23, 2018 and April 10, 2018; accepted May 11, 2018. Date of publication May 23, 2018; date of current version September 17, 2018. Paper 2017-PSEC-0795.R2, presented at the 2017 IEEE Industry Applications Society Annual Meeting, Cincinnati, OH, USA, Oct. 1–5, and approved for publication in the IEEE TRANSACTIONS ON INDUSTRY APPLICATIONS by the Power Systems Engineering Committee of the IEEE Industry Applications Society. This work was supported in part by the National Research Foundation of Korea funded by the Korea government (Ministry of Education, Science and Technology) under Grant 2016R1E1A1A-02920095 and in part by the Korea Electric Power Corporation. (Corresponding author: Jung-Wook Park.) S. H. Lee is with the Department of Electrical and Control Engineering, Mokpo National University, Jeonnam 58554, South Korea (e-mail:,

Publisher Copyright:
© 1972-2012 IEEE.

All Science Journal Classification (ASJC) codes

  • Control and Systems Engineering
  • Industrial and Manufacturing Engineering
  • Electrical and Electronic Engineering


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