Effects of hybrid storage systems with supercapacitors on the distribution network

In the contemporary context, the escalating demand for energy has given rise to significant challenges pertaining to the quality of power, the continuity of energy supply, and the balancing of loads within electricity distribution networks. This is particularly evident in the context of integrating renewable energy sources into the system, which has resulted in a more complex grid dynamics and an increased need for flexible, fast-response, reliable system solutions to sudden load changes. Energy storage systems have become an attractive solution alternative thanks to their ability to combine components with different energy densities and response times in the same structure. This thesis proposes a hybrid energy storage system, comprising a lithium iron phosphate (LFP) battery and a supercapacitor. The system has been designed and evaluated in real field conditions with a view to improving power quality and supporting grid stability in low voltage distribution networks. The configuration of the system is achieved through the balancing of energy and power density, and it is integrated in parallel with the grid via an inverter. The experimental setup encompassed two distinct scenarios: the system's operation exclusively on grid energy and its operation with the hybrid system enabled. The measurements were analysed in terms of frequency and voltage stability, voltage instability, harmonic and superharmonic distortions, transients and ITIC curve. The findings demonstrate that the integration of the hybrid system into the grid does not result in grid damage, enhances power quality by constraining voltage fluctuations, and optimises system performance in the face of transient events. The findings of this study demonstrate that hybrid energy storage systems provide a significant solution, not only in terms of energy management, but also in terms of power quality continuity and system security. The findings provide a technical basis for a more widespread and scalable implementation of these systems in distribution networks.