**Accuracy Improvement Method of Energy Storage Utilization with DC Voltage Estimation in Large-Scale Photovoltaic Power Plants**

### **Yeuntae Yoo 1, Gilsoo Jang 1, Jeong-Hwan Kim 2, Iseul Nam 2, Minhan Yoon 3,\* and Seungmin Jung 2,\***


Received: 27 August 2019; Accepted: 15 October 2019; Published: 15 October 2019

**Abstract:** In regard to electric devices, currently designed large-scale distributed generation systems require a precise prediction strategy based on the composition of internal component owing to an environmental fluctuating condition and forecasted power variation. A number of renewable resources, such as solar or marine based energies, are made up of a low voltage direct current (DC) network. In addition to actively considering a power compensation plan, these generation systems have negative e ffects, which can be induced to a connected power system. When a storage is connected to a DC-based generation system on an inner network along with other generators, a precise state analysis plan should back the utilization process. This paper presents a cooperative operating condition, consisting of the shared DC section, which includes photovoltaic (PVs) and energy storage devices. An active storage managemen<sup>t</sup> plan with voltage-expectation is introduced and compared via a commercialized electro-magnetic transient simulation tool with designed environmental conditions. Owing to their complexity, the case studies were sequentially advanced by dividing state analysis verification and storage device operation.

**Keywords:** PV diagnosis; ESS application; DC power flow; DC system dynamics; hybrid generation system
