Distribution system voltage stability analysis with wind farms integration

As the installed capacity of wind power generation is increasing continuously, its impacts on system voltage stability have been intensively studied in recent days. In this paper, only the wind farms connected to distribution network are treated. Wind gusts will produce output power spikes and cause poor feeder voltage regulation, which may lead to voltage collapse when there is no sufficient reactive power support. An accurate voltage stability index (VSI) is needed to quantify the voltage stability margin in real time. This paper addresses such an index for distribution systems, where the required measurements are available only at feeder roots. The proposed VSI has been implemented in simulations with wind farms integrated. Simulation results are presented to examine the performance of both fixed-speed wind turbine and variable speed wind turbine. STATCOM is also included to demonstrate its capability for voltage stability improvement.