An Out-of-step Splitting Strategy Based on WAMS Information for Oscillation Center Migration under Multi-Operation Mode

The increasing development of the large-scale southwest hydropower and the AC /DC transmission leads to power angle stability issue. Based on equivalent three machine system model, this paper deduces the function expression of voltage amplitude and position of multi-frequency oscillation center. The function is affected by power potential amplitude ratio, line impedance, frequency of power potential and initial phase of power potential. Thus, the performance of the out-of-step splitting device is influenced by the change of operating mode and migration of oscillation center affect. Therefore, the out-of-step splitting device cannot be well applied in the multi-frequency out-of-step scenario. On this basis, this paper proposes a new out-of-step splitting strategy for oscillation center migration under multi-operation mode based on WAMS information. In detail, the proposed strategy can obtain bus voltage amplitude/phase information provided by WAMS and local Ucosφ criterion to determine position of out-of-step oscillation center and out-of-step period. The simulation results show that the influence of different power system operation modes on the migration characteristics of oscillation center is correctly applied in multi-frequency out-of-step oscillation scenario, and the proposed strategy based on WAMS information has a good adaptability under different operation modes.