The impact of wind generators on voltage control of the network has been analysed via a statistical approach. A probabilistic model was developed by taking into consideration the stochastic nature of the wind and the availability status of the network elements. The proposed statistical method estimates the voltage deviation at the point of common coupling and its probability of occurrence. An index, termed significant level of voltage deviation, has also been proposed to aid in evaluating strategies for mitigating voltage quality problems. Numerical case study is presented to illustrate the proposed method and to compare its performance against other methods.