The Influence Of Generator Excitation System On Power System Stability

As the expansion of grid scale, the operation is more and more complex, and the same with difficulties of operation in system security assurance. The problem of security and stability of power grid is increasingly significant. Improvement and maintenance of stability in synchronous generator is one of conditions which assure the security and economic operation in power system. Among all the measures which improve the operation of generator, enhancing the performance of excitation-system controlling is acknowledged to be one of economic and effective methods.With the development of modern complicated power system, the accuracy of the simulation requirements to be higher. In the past years, Synchronous generator excitation system classic model was widely used because of lacking accurate data so that the result could not reflect the real operation conditions. The real model identified from field data has been adopted in this paper which can represent accurately the actual dynamic responses of the generator and its excitation system based on the excitation parameters measurement of Qinghai Electric Power System. The variation rule of transient stability level is comparing with the classic model, taking the contingency clearing time as a basic index, and this paper can support the operation and optimization of the power system better.When the measured excitation model is adapt in Qinghai grid, transient stability varies with the ways of faults in power system, some failure modes improving transient stability, some not changing, but not reducing the transient stability. Overall, it can improve transient stability of the power grid. Because only part of generators using the measured excitation model, if we want to know whether the parameters of actual measured excitation accurate, reasonable or not, we need a large number of model parameters measured to verify, so that speeding up the measured work is more and more important for the modern large-scale power system.In short, this paper analyzed theoretically power system stability characteristics; secondly, the model of excitation and generator is analyzed, and point out the choice of model and parameters has an critical influence on the simulation accuracy and reliability of power system; finally, that the generator excitation system impacts on transient stability and damping characteristics of the grid is analyzed by simulation calculation.