Application of 500kV UPFC in Suzhou southern power grid

The implementation of a 500kV unified power flow controller (UPFC) project in Suzhou southern power grid is reported in this study. The UPFC project has been put into operation at the end of 2017, and has become the largest capacity and highest voltage-level UPFC in the world. The overview of the Suzhou southern power grid is first introduced. The challenges of the grid, such as the limited transmission capability and the insufficient reactive power supply, are also demonstrated. Great technical and economic difficulties have to be overcome for the implementation of traditional solutions, so an attempt of the UPFC scheme is put forward. The UPFC scheme is introduced in detail, including the topology structure, the main equipment selection, the expected effect, the implementation difficulties and the investment. It is shown that the 500kV UPFC project is more economical and feasible than the traditional solutions. The operation problems of the Suzhou southern power grid will be alleviated effectively by the UPFC project. Besides, this project is of much demonstration value to the application of high-voltage-level and large rating UPFC projects.