**1. Introduction**

Recent advances in the field of energy has shown that the penetration rate of photovoltaic (PV) power generation is expected to increase steadily over the next decade [1]. The existing small-scale PV systems dominating local demand has been replaced with bulk farm systems to take advantage of environmentally friendly policies as described in [2]. Until now, network operators have focused on the characteristics of large-scale power generation systems and have focused on increasing its capacity. To add to this, the demand for properly managed generated power has been derived due to grid expansion. The recently revised IEEE-1547, particular momentary cessation, illustrates these requirements of related industrial sectors [3]. Currently, PV systems with a capacity of one gigawatt or more are implemented worldwide, including an operating system to enable compliance with directives of system operators. In a PV farm, several sets of megawatt (MW) arrays are built, which should interact with centralized topologies. The need for a control strategy that focuses on the detailed specification of PV is increasing and may be a major challenge in the power system industry that focuses on stochastic uncertainty.

Although renewable energies supply smoothed energy by composing a farm network, the operators still demand advanced solutions for flexible power managemen<sup>t</sup> with additional compensators [4,5]. However, most major storage applications are still geared to play a role in responding to demand rather than providing real-time compensation [6]. As described in [7], since the requirements in terms of response between the farm and operators have expanded, the power system industry has considered advanced real-time solutions. The study in [8], depending on the various practical conditions, emphasizes the importance of real/reactive compensation response. Reactive power compensation generally focuses on voltage fluctuations in the local energy system, but conversely, real power compensation requires control that focuses on supply and demand of the entire system. These real power reactions are achieved with the aid of detailed backup control of the energy storage system (ESS) based on power conversion systems (PCSs) which are performed with optimized signals generated according to the main system criteria as in [9–11].

Newly developed renewable energy has been generalized to connect to a grid through full-converter based PCS. A process for combining renewable sources has been commercialized with a study on how to treat an independent DC section as a cluster as in the concept of multi-terminal DC [12]. The main objective of this approach is to improve its control capability by sharing the imposed order from a transmission system operator (TSO) with each distributed energy source (DES) in the cluster. Since PV requires a relatively small geographical area, the concept has been preferentially applied to existing farms along with possible storage system [11]. In a PV based hybrid DC system, which adopts a storage application, to perform precise control in a region where there is a number of DESs, a compensatory calculation process for each signal may be necessary. With regards to this, a proposal about a voltage calculation method based on a power flow analysis that considers the current flow between the PV modules is presented in [13], with detailed description of a practical ESS application. The possible voltage fluctuations generated between cables which were reported in [14,15] was reflected and analyzed in [13].

In this paper, in the signal dispatch process of a hybrid system, a feasibility analysis about proceeding with order managemen<sup>t</sup> while calculating an appropriate voltage was derived. The main objective was to check the feasibility of an ESS compensation scheme which applies a voltage signal calibration in order to implement a power managemen<sup>t</sup> plan for a hybrid system according to the applied load. Previous formula descriptions were expanded to enable it to deal with practical voltage variations. To carry out a practical approach in which an included PCS controller manages not only the voltage of each DC section but also the calculation delays, a simulation analysis was studied and confirmed with the consideration of real power that changes continuously. Focusing on a distribution network, the voltage impact was established and analyzed to check the availability of additional signal compensation plan. The ESS model configurations, including control topologies, are composed as in [13] to implement a reasonable case design.
