Research On Predictive Algorithm For Power System Frequency Stability Based On Wams

Frequency is an important indicator of the operational quality and safety of power system, frequency stability is a matter of the whole to guarantee the security and stability of power system. The gradual region interconnection of power system make the system's economical efficiency and reliability greatly improved. But along with the enlargement of electricity grid scale and the adoption of kinds of new transmission technology, the power grid structures become more complicated increasingly, the system dynamic behavior also become more and more complicated, the ability of maintaining power system frequency stability is getting worse, the possibility of suffering an chain accident from stability disruption has greatly increased. Therefore, using the global information to analyse and control the frequency stability has become a urgent need of morden power system.The appearance of WAMS(wide-area measurement system) has realized the real-time measurement of the wide area power grid, a mass of measured data could be summarized by the high-speed network, it provides a good condition for power system's global safety monitor and control. Using the real-time data from the WAMS to get fault transient information of the system, predicting the steady frequency after a certain disturbance so as to take effective measures to prevent the power system from frequency collapse.The frequency response characteristics of power system are summarized in this paper, existing methods for frequency stability analysis are introduced and analyzed. The present status and future prospects of WAMS in power system are introduced, informed predictive algorithms for power system frequency stability based on WAMS are also studied. The accuracy and complexity of two kinds of power system frequency stability predictive algorithms based on WAMS are compared and analyzed in theory. By modifying the steady frequency predictive equation of the rectangular form frequency stability predictive algorithm based on WAMS, a fast predictive algorithm for power system frequency stability based on WAMS is proposed.The proposed fast algorithm is achieved on the IEEE's 50-generator modified test system by the FORTRAN-Language program and Monte Carlo method, the results prove that the proposed fast algorithm has a high accuracy and a fast resolving speed. Load models have an important influence in power system design, analysis, and control, the effectivity under different load model schemes of the three kinds of power system frequency stability predictive algorithms based on WAMS is studied by simulation. Getting, transmitting and processing the information from the power system has been more convenient through WAMS, while, the other side of WAMS can not be ignored:time-delay, the impact to the three kinds of power system frequency stability predictive algorithms based on WAMS is studied by simulation under different communication delay.