• The wind speed can significantly impact the loading margin of the power systems. • Precise estimates of the loading margin are obtained for wind speed perturbations. • The quadratic estimate is generally more accurate than the linear estimate. • The synchronous generators dispatch is accurately estimated after wind speed changes. • Estimation errors tend to grow with greater perturbations, but are still acceptable. The main objective of this paper is to evaluate the impacts in electrical networks, particularly on the voltage stability margins, due to the presence of Wind Generation (WG) and its intermittent characteristic. For this purpose, linear and quadratic sensitivities of the Loading Margin (LM) with relation to the wind speed are calculated, and then utilized to estimate possible alterations in the LM due to perturbations in the wind speed of the wind farms. To include the variable wind speed in the sensitivity analysis of the LM two types of wind generators are mathematically modeled and then incorporated into the power flow formulation. Lastly, three case studies are performed, where accurate estimates of the LM are obtained for wind speed perturbations in the wind farms, demonstrating the effectiveness of the proposed methodology and its potential to assist in the real-time operation and the operation planning of power systems with WG. [ABSTRACT FROM AUTHOR]