Ramp-Rate Control for Mitigation of Solar PV Fluctuations with Hybrid Energy Storage System

Abstract

This paper proposes a ramp-rate control (RRC) for mitigation of solar PV fluctuations with a hybrid energy storage system (HESS). The highly fluctuating primary energy source causes photovoltaic (PV) generators to suffer from variable output capacity. Such variations can lead to instability in power systems and problems with power quality due to large PV penetration. The role of energy storage devices (ESSs) as a fluctuation compensator is suggested to minimize these issues using RRC. Distributed Generation Systems (DGs) have become a key challenge as the disruption of DG from the grid during faults results in severe difficulties such as power outages and voltage flickers. Low voltage ride through (LVRT) is a promising method for supplying reactive power under low voltage conditions. The proposed method will enable dynamic control of integrated battery storage (BS) to mitigate power fluctuations during the day while simultaneously charging or discharging the integrated super-capacitor (SC) storage to control sudden variations in a BS to a certain magnitude. A system for exchanging energy between the BS and the SC storage provides uninterrupted control of the rapid fluctuations of the passing cloud. The storage capacity savings are evaluated by using the RRC for the smoothing impact of geographical deflection on PV power production. Simulations conducted with real operational PV power output data taken every 1 s from the power plant during one year confirm the validity of the model. The OP-5700 HIL test-bench is used for the real-time results.