**5. Conclusions**

This paper confirms the feasibility of the voltage-estimation method for a MW-scaled hybrid system. Existing signal correction methods to assist ESS operation were analyzed and utilized. The possible delays in calculations that occur with real power managemen<sup>t</sup> were used in case studies. In designed simulation, the voltage-estimation method showed robustness in target topologies (multistring, central).

In response to the changed load condition, the voltage-estimation method acts to generate a modified order considering the actual required power extraction and calculation load. Focusing on the computational load caused by the expansion of a single PV system, we have analyzed the convergence of the PCS signal with the iteration method. With respect to this, a calculation delay could be generated not only by the PV module, but also by the applied sensor. Although this can be improved with detailed gain adjustments or by using a correction method according to the response characteristics, these circumstances need to be considered in the ESS managemen<sup>t</sup> plan in advance. Therefore, a possible situation about signal calculation was derived, tested, and listed based on previous simulation design. In the aspect of the inverter topology, the possible delays need to be considered in advance when configuring the system. This operation can improve the accuracy both of the state of charge estimation and response operation.

**Author Contributions:** Conceptualization, J.S. and S.J.; Methodology, S.J.; Software, J.S.; Validation, J.S., and S.J.; Formal analysis, J.S., S.J.; Investigation, M.Y.; Data curation, M.Y.; Writing—original draft preparation, S.J.; Writing—review and editing, J.S. and S.J.; Supervision, S.J.; Project administration, S.J.; Funding acquisition, S.J. All authors have read and agreed to the published version of the manuscript.

**Funding:** This work was supported by the National Research Foundation Grant (No. 2018R1C1B5030524) and the Korea Electric Power Corporation Grant (R18XA06-40) funded by the Korean government.

**Conflicts of Interest:** The authors declare no conflict of interest.
