Adaptive energy filters smoothing renewable power fluctuations at different power levels

摘要

Renewable energy is playing an increasingly important role in modern and future power system. However, most of renewables (wind, solar and wave) have huge power fluctuations, which cause frequency variations, voltage flickers, forced oscillations, thermal excursions and wasted capacities of equipments and generally undermine the system stability. In previous works, energy filters are proposed to smooth renewable power fluctuations without input power measurements. However, conventional controls of energy filters require good estimations of average input power levels to manage energy storage systems. In this paper, a new control method is proposed to make energy filters adaptive to the change of input power levels, which is no longer estimated as a constant but is given by an adaptation law in real time. Proposed control laws are comparatively studied with conventional energy filter controls in terms of their filter responses, ESS responses and parameters selection. The proposed adaptive energy filters are demonstrated based on RTDS simulations. Results show that adaptive energy filters are able to smooth renewable power fluctuations and meanwhile regulate its energy storage level when the input power level changes.