Research on flexible excitation system applied to improve transient stability characteristics of the receiving-end power grid

The transient forced excitation of the traditional excitation system used for synchronous condenser is limited and unmaintainable. A flexible excitation system can improve the crest value of transient forced excitation and maintain the forced excitation capacity during and after faults through DC bus voltage control. Therefore， a study is conducted on applying a flexible excitation system for critical units to improve the transient stability characteristics of local power grids. The hardware topology and control method of flexible excitation are introduced， and the flexible excitation control objective to enhance the transient stability characteristics of the units is analyzed. The flexible excitation is applied to the critical units in the actual grid at the receiving end with transient stability problems. The transient stability enhancement effect of the grid is verified in the simulation after the application. The results show that applying flexible excitation to a limited number of critical units can effectively improve the transient stability characteristics of power grid.