Along with the advance of the smart grid, more and more new energy is introduced into the power system, especially wind power. Their natural characteristics like stochastic capacity and intermittent fluctuation produce an impact on the power grid's operation security. This paper takes many uncertain factors into account such as the variation of loads and generator outages. In this paper, a Beta distribution model is built to describe the short-term production of the wind power and probabilistic load flow which combines the concept of semi-invariant and Improved Von Mises method is presented to obtain the probability distribution function (PDF) and the cumulative distribution function(CDF) of node voltages and transmission line flows. Three static security evaluation indices are introduced in this paper for planning and real time operation respectively. The calculation on the IEEE RTS-24 node test system not only shows the static security evaluation indices, but also provides preparation for the location of wind power plant and maximum wind power capacity. The case indicates that this method can analyse the real time static security of smart grid with new energy injection rapidly and accurately, and is with practical application value.