Supercapacitor energy storage systems for voltage and power flow stabilization

Abstract

The variable output of renewables such as wind and solar causes fluctuations of power flow that can adversely affect power system operation, especially at high levels of penetration. The coordination of multiple energy storage solutions can mitigate integration challenges by providing a buffer from variable renewables. This paper presents the integration of supercapacitor energy storage through a grid-tied inverter system that can then be used in combination with other energy storage solutions such as batteries to enhance the overall grid-tied energy storage solution. Control algorithms are developed for the supercapacitors to enhance the stability of the power system. In addition, a key parameter that is analyzed is the effective supercapacitor energy rating and state of charge (SOC). This paper includes both simulation and experimental validation of the rapid bidirectional power flow of supercapacitor energy storage systems, as well as the model implementation of these devices through an in-lab grid to smooth high ramp rate events seen in solar data.