Research On Distributed Generations In Smart Grid To Improve Network's Power Quality

The increasing electricity demand and environmental pressure have been promoting the advancement of distributed generations (DG). Accorind to reports published recently, DG has taken up 25% to 30% of world's genration units. Besides, wind power is a renewable energy resourse without additional fuel costs, which has become the fastest growing renewable energy source, the most promising energy resourse that can be used vastly in the future. The development of power industry in China witness the same tendency as well. However, wind generation is unpredictable as wind force changes randomly, thus leading to the variations of output power from the wind generators. And wind farms often locate in remote areas, far from the load centre, that forms a weakly connection of the wind farm to the main power network. That is to say, wind generation will be effective in reducing fuel costs, but not conducive to the security of the system. To make best of wind energy, on the premise of en-suring system security, is a very timely subject:1. Based on rules avowed in "Power System Security and Stability," in conjunction with the specific power and the characteristics of wind farms, a index system has been established, covering the field of power quality, reliability, penetration level and so on, which can be a reasonable way to evaluate the wind generation integrated grid systematacially and scientifically.2. The Power Flow including wind generations have been built up and relevant calculaton models have been set up.3. Wind power penetration limit has been presented in this paper, and the proposed method have been applied to the practical power grid.4. Several conclusions have been drawn with quantitative analysis of wind farm integrated into a practical power nerwork and research on penetration level in detail, which will be some kind of references to furture works.