Performance Analysis of UPFC and DPFC in a Grid-Integrated Hybrid Solar–Wind System

In this work, a relative inspection is performed with distributed power flow controller (DPFC) and unified power flow controller (UPFC) connected to a solar–wind hybrid system. The hybrid system consists of dual sources for renewable energy as solar and wind. Solar generation system followed by a boost converter is useful to raise the level of DC power from the solar energy. On the other hand, wind generation system followed by a diode rectifier and boost converter amplifies the energy received from wind source. Now DC obtained from both the sources is coupled to a common DC bus to get the DC link voltage which eventually is applied as input to the grid side two-level voltage source inverter (VSI). The grid side demands control actions and monitoring perfectly due to the presence of distortions, noise, power losses, etc. Reactive elements reduce these problems up to a certain extent, but it increases the possibility of sub-synchronous resonance phenomenon and extra inductive and capacitive losses. Moreover, the power factor is also affected considerably. Thanks to the emerging FACTS technology, which controls as well as increases the utilization of transmission lines to its full thermal limits. Unified power flow controller (UPFC) is one of the latest FACTS devices available today. It controls the power flow through the lines by varying line inductances, transmission angles and voltage magnitude. The disadvantage of UPFC is its immensely high rated three-phase series–shunt converters and the increased ripple content in output grid voltages and currents. These problems are overcome by a newly invented FACTS device, namely distributed power flow controller (DPFC), which uses small single-phase series and shunt converters. The paper studies the effect of incorporating UPFC and DPFC to hybrid solar–wind system. Additionally, working principle of both the devices was presented. At the end, results from MATLAB simulation are used to support the claim of DPFC being superior to UPFC.