In the United States, wind power generation accounts for approximately 0.6% of the total, and Renewable Energy Laboratory conducted an investigation as to how 20% of energy from wind will look like in 2030. The modern wind power plants can be as large as 300 MW and are often located within a short distance of each other. With respect to power system analysis and transient stability analyses, interconnections of wind power stations with grid systems pose even larger problems, which require a more thorough analysis of the interconnection and system isolation under disturbances. Investigations of transmission transfer capability with wind power generation become important. The varying nature of wind power generation and system voltage instability and transient stability are essential parameters. In the beginning of wind power development, the energy produced by small wind power turbines was expensive and subsidies were high.