Study On The Five Stages Excitation Control Technology To Improve Transient Stability

With the rapid development of modern power system, the operation of UHV AC/DC transmission line, operation of the large-capacity generators, wide application of flexible AC transmission system, long distance transmission and regional power grid interconnection make the power system more and more complicated, and more sensitive to interference. It is an important and long-term research task to enhance the stability of the power system. Among them, the transient stability is an important defense for system stability, the generator excitation control as an economical and effective means of improving the system transient stability has been given much attention.In order to fully explore the potential of the excitation system to improve the power system transient stability, and to develop a smart excitation control device which can improve the stability of generator and power system, this paper studies the five stages excitation control method in transient process. The main contents include:(1) Based on the original five stages of excitation control theory, this paper perfected the five stages excitation control theory and its realization method. Added the third stage excitation control of the transient process, to reduce the reverse swing magnitude of the power-angle after a failure. Completed the start and exit criteria of five stages excitation control, to ensure the actions.accuracy of the five stages excitation control.(2) Established a excitation control simulation model by the custom modeling platform in Power System Analysis Software Package (PSASP). This model can be used for large-scale power system load flow and stability calculations. The North China-Central China-East China power grid is taken as an example. This model is used for transient stability simulation calculation in different failures. These failures occurred in the Sichuan power grid and near the UHV tie line The results show that the five stages excitation control can significantly reduce the oscillation amplitude of power-angle after a system failure and play a positive role in the voltage stability of power grids and the recovery of the fault.he five stages excitation control can improve transient stability of the power system. (3) Cooperating with Beijing SiFang JiSi electric co., LTD., a five stages excitation control device prototype is developed on the basis of generator and excitation control system GEC-300. Its core adopts the advanced control theory and the mature fully digital microcomputer control principle. It has the advantages of high reliability, fast response, high speed and precision control, friendly interface, etc., implementing the intelligent excitation control in transient process.(4) A rigorous software testing and laboratory verification are completed based on the Advanced Digital Power System Simulator (ADPSS) electromechanical-electromagnetic hybrid simulation platform. Prototype is checked and accepted by the expert group. The verification in the North China-Central China-East China power grid digital and analog hybrid simulation system shows that the five stages excitation control device prototype’s test results are correct, the operating characteristics meet design requirements.