Emergency Control Strategy of Ultra-low Frequency Oscillations Based on WAMS

In this paper, an emergency control strategy of ultra-low frequency oscillations (ULFO) is presented. The multi-signal Prony algorithm is used to identify frequency signals from WAMS. Then the criterion of ULFO is proposed based on the Prony analysis results. After that, the control strategy considering both switching control modes of governor and taking out of the primary frequency modulation is applied to damp the ULFOs. At last, the process of the emergency control strategy is proposed. Applications in regional power system in Sichuan Power Grid and Southwest Power Grid of China verify the effectiveness and practicability of the proposed strategy.