Search

SUMMARY The paper presents an unbalanced three-phase power-flow model for wind turbine generating systems (WTGSs). The model takes into account voltage unbalance factor which exists at the point of common coupling. The developed model is integrated with the unbalanced forward/backward sweep power-flow method. The model comprises of three main components: they are the wind turbine, induction generator, and interface transformer to the grid. Due to their design symmetry, the generator and the transformer are modeled using symmetrical sequence networks. The results show that the developed model has robust convergence characteristics. The solution of the IEEE unbalanced radial feeders shows that the injected powers per phase due to the WTGS are not equal and strongly dependent on the voltage unbalance factor. The results also show that the simplified models based on positive sequence network lead to inaccurate overall power-flow solution. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Voltage fluctuation and voltage rise are common issues associated with the massive integration of photovoltaic (PV) technologies in distribution systems. In this paper, sensitivity-based and optimization-based methods are proposed for mitigating voltage fluctuation and rise in the presence of plug-in hybrid electric vehicles (PHEVs). The concept of these methods is to optimize the reactive power of PV inverter and active power from charging station of PHEVs for matching a target voltage profile. The sensitivity-based method is based on the first-order power flow sensitivities around the desired voltage profile. An optimization model is used in optimization-based to minimize the mismatches between the fluctuating and required voltage profiles. The charging/discharging operation of PHEVs and reactive power of PV inverter are simultaneously controlled for compensating power fluctuation during cloud transients and load fluctuations. The results demonstrate the effectiveness of the proposed methods compared with existing methods. [ABSTRACT FROM AUTHOR]