Contribuição de um sistema de armazenamento de energia por meio de baterias para regulação dos níveis de tensão de um sistema de distribuição com alta penetração fotovoltaica

Abstract

The impacts of distributed generation (DG) in electricity distribution networks need to be studied so that their connection is indeed capable of improving the system operation. Thus, the influence of distributed generation on the voltage profile is an important issue to be considered, since it is directly linked to the quality of the supply of electricity to end consumers. Within this scenario, knowledge and the use of methods that are adequate to control the relationship between the generation and the device that will have the function of providing voltage support (batteries) become necessary, so that the voltage in the distribution system is keep within acceptable values. Thus, this research presents the investigation of different strategies for operating a battery bank in distribution systems with the influence of high photovoltaic penetration. For this purpose, the work considers the modeling of the DC/DC Boost converters, bidirectional DC/DC converter in current and the DC/AC Voltage Source (VSC) converter, with their respective control loops, the synchronism circuit (SRF-PLL) (Synchronous Reference Frame Phase-Locked-Loop) and the Maximum Power Point Tracking (MPPT) technique. Simulations were performed using the Matlab / Simulink software, in which the Cigré 18 low voltage (BT) test system modeling is developed, containing, in addition to the converters, the photovoltaic generators and a battery bank. Real curves were considered for both solar radiation and system loads. The proposed technique showed, through simulation results, the implementation of a comparison tool, applied in the Bidirectional DC/DC converter, in which, based on the implemented logic, a reference value is determined for the battery charge and discharge (depending on the value in the PAC). This tool was also adapted to control the active and reactive power of the VSC, taking into account the injection power and consumption of BESS, presenting as techniques for the battery to provide voltage support for the system under analysis. The results obtained with BESS are satisfactory, showing their local influence, that is, where the voltage profile at the Common Coupling Point (PAC), in which the battery is inserted together with the photovoltaic panel seen against the established values, also showing the impact on the tension of the bars adjacent to the connection point, even for the bars furthest from the BESS installation.