Analysis and control of stochastic power fluctuations on the tie-line of interconnected power systems

On the tie-line of interconnected power systems, there inevitably exist power fluctuations. Overlarge undulations on tie-lines threaten the stability and security of the system. It is remarkable that when the control areas are larger, the situation becomes more austere. In this paper, based on the practical data of two large interconnected power systems, the stochastic power fluctuations of the tie-line, the only 1000kV AC transmission line in China, are analyzed by frequency-domain methods. It is found that the component with a specific period is prominent in the fluctuations. The cause of this special phenomenon is then explained by analysis of ACE (Area Control Error) real-time adjustments, an important function of AGC (Automatic Generation Control) system. Finally, on the basis of the results above, the paper proposes methods to improve the control effect of tie-lines.