Security-Constraint Unit Commitment for AC/DC Transmission Systems with Voltage Stability Constraint

Due to the inherent characteristics of weaker voltage supporting ability, line-commutated converter based HVDC technologies have significant effects on AC/DC hybrid power grid’s voltage stability. These has led to new challenges for power grid operators in terms of ensuring power system security. To address these challenges, a unit commitment of receiving-end in AC/DC hybrid grid is presented in this paper. In the proposed model, we employ static voltage stability constraints to guarantee enough voltage supporting capacity from thermal plants at HVDC feed-in area. Based on the characteristics of the model, Benders decomposition and mixed integer programming algorithm are used to get the optimal transmission power of HVDC and schedule of thermal generators. The study is done by considering IEEE-39 and Jiangsu power grid in eastern China, containing two and three HVDC transmission projections respectively. Numerical results on two benchmark problems illustrate the effectiveness of the proposed algorithm, both in terms of convergence rate and solution quality.