Application of energy capacitor system with minimum energy storage capacity for smoother frequency and output power of a grid connected wind farm

Abstract

Stability enhancement of output power and frequency in grid connected wind farms are major challenges nowadays. A model of a grid connected wind farm consisting of a fixed speed wind turbine based induction generator (IG) connected to the transmission line with an energy capacitor system (ECS) in parallel has been considered in this research work to analyze the output characteristics. ECS consists of converters, inverters along with electric double layer capacitor (EDLC). Choice of line power reference is one of the major factors for stable output power and frequency of the wind farm. In this paper simple low pass filter (LPF) method has been applied to generate line power reference for ECS. It has been revealed from the outcome of the research that line power reference and frequency of the output power obtained is more stable using LPF method. Furthermore, LPF method requires a shorter charging-discharging time and smaller storage capacity. Moreover, a control system is proposed which employs a lead lag compensator for smoothing the output power much more even during fault conditions. PSCAD/EMTDC software is used for simulation purposes.