Paper Title
Improvement Of Voltage Regulation In Wind Farm To Weak-Grid Connection Using UPQC

Abstract
Wind Power is one of the Renewable Energies with a greater future projection. This is due to the existence of non-exploited wind resources and to the fact that it is a clean and environmentally friendly energy source. Wind Farms (WF) employing squirrel cage induction generator (SCIG) directly connected to the grid. In facilities with moderated power generation, the WF is connected through medium voltage (MV) distribution headlines. A situation commonly found in such scheme is that the power generated is comparable to the transport capacity of the grid. This case isknown as Wind Farm to Weak Grid Connection, and its main problem is the poor voltage regulation at the point of common coupling (PCC). Thus, the combination of weak grids, wind power fluctuation and system load changes produce disturbances in the PCC voltage, worsening the Power Quality and WF stability. This situation can be improved using control methods at generator level, or compensation techniques at PCC. In case of wind farms based on SCIG directly connected to the grid, is necessary to employ the last alternative. Custom power devices technology (CUPS) result very useful for this kind of application. In this paper is proposed a compensation strategy based on a particular CUPS device, the Unified Power Quality Compensator (UPQC). A customized internal control scheme of the UPQC device was developed to regulate the voltage in the WF terminals, and to mitigate voltage fluctuations at grid side. Simulations results show the effectiveness of the proposed compensation strategy for the enhancement of Voltage Regulation and Wind Farm stability.