Energy storage system specification and allocation for a distribution system with distributed generation

The main focus of this paper is to specify and allocate an Energy Storage System (ESS) for a distribution system, which presents a Distributed Generator connected, in order to adjust the network voltage levels according to the limits established by Brazilian standards. For this, the IEEE 13-bus test feeder system was modeled using the Real Time Digital Simulator (RTDS). This system has been adapted due to the simulator's processing capacity and appropriated voltage limits. The simulated system presents a 2.5 MW solar power plant, which is composed by photovoltaic panels, an inverter, and a transformer for coupling in the network; in addition to the energy storage system, that consists of a 2.5 MWh lithium-ion battery bank, a converter/inverter, and a control block. The specification as well as the allocation of the ESS was given by an investigative study. After this, some scenarios were created to verify how the ESS behaves to adjust the system voltage levels to the desired limits. It was verified that when the system is in a low load profile with the maximum power injection of the distributed generator, a voltage rise occurs, leading the system to exceed the established voltage levels. Thus, the ESS has shown effectiveness because it kept the system operating according to the standards by absorbing part of the generation.