Analysis of ULFO Including Hydro Governor Effects and Additional Controller Design for Asynchronous Systems

This paper applies an electromechanical transient model to the analysis of ultra-low frequency oscillations (ULFO) in Chongqing-Hubei asynchronous power systems. The electromechanical model of Back to Back MMC-HVDC is established firstly. Emphasis is put on the contribution of hydroturbine governors to UFLO and additional damping controller design. The prolonged oscillations in the simulation is analyzed with power system analysis software package (PSASP) model, while additional controller in rector converter station is designed that proves to be effective in damping out the ultra-low frequency oscillations.