Investigation of switching over-voltages with different wind farm topologies

With increasing wind farms scale, the practical problems become more complicated. One of the prominent problems is over-voltage production due to frequent switching activity. The over-voltage cruelty mainly depends on the wind farm topology, defined for an arrangement of the wind farm feeders between the turbines. In this paper, the switching over-voltages in different wind farm topologies are presented by simulating ZAAFRANA wind farm in Egypt with the support of DIGSILENT. First, the four different topologies named radial, single-sided ring, double-sided ring, and star, are examined by measuring the generated over-voltages. Finally, based on the more accurate and comprehensive analysis of the over-voltage produced by the four topologies, an effective methodology is proposed for reducing the amount of the over-voltage peaks, in the low-cost radial topology, by splitting the switching process into two stages. The proposed methodology is applied to ZAAFRANA wind farm and found that the destructive effects are reduced remarkably.