The use of renewable energy sources is escalating every year. Thus, there is an increase of smaller generating units connected directly to distribution networks close to demand consumption, designing micro-grids. These sources must provide the power quality required to ensure the stability and reliability of the power system. Several studies are demanded to ensure system operation in a secure maimer. However, one has an issue regarding generation uncertainty when a distribution system presents many micro-generators. This is due to the uncertainty of primary sources, such as wind and radiation. In this paper, voltage stability reliability in distributed generation is held using simulation techniques. Thus, the voltage security analysis is jointly considered with probability laws. Moreover, reliability theory is also considered in the voltage collapse analysis methodology proposed here. (6 pages)