The Joint Application of Photovoltaic Generation and Distributed or Concentrated Energy Storage Systems in A Low Voltage Distribution Network: A Case Study

Over the last decades, Distributed Generation (DG)was presented as a possible alternative for integrating renewable energy sources into the electrical system. This resulted in the continuous growth of the investment and interest of small consumers in acquiring ways to generate their energy through mini distributed generation. However, with the high DG penetration in Low Voltage Distribution Networks (LVDN), technical challenges are being observed and, in some instances, the worsening of indexes related to Power Quality (PQ) and economic conflicts. In this context, this work presents the improvements achieved by integrating Photovoltaic DG (PV-DG) with Energy Storage Systems (ESS). Proposed scenarios are analyzed in which the storage occurs in a distributed way, with an ESS connected to each PV-DG, or in a concentrated way, with a single ESS connected to the main transformers secondary side. The energy stored during prolonged periods of residential consumption is also analyzed to evaluate the ESSs capacities to retain the PV-DG surplus and supply the increases in power demand. In general, the combination of these distributed resources displayed improvements in voltage levels, unbalance and reduced technical losses. The concentrated ESS demonstrated a better use of both its storage capacity and energy. However, the voltage unbalance has increased due to the inverters operation that connects it to the grid.