Comparative Ranking of Critical Uncertainties Affecting the Stability of Mixed AC/DC System

Power systems are accommodating an ever-increasing number of sources of uncertainty due to the proliferation of renewable energy sources (RES) and new types of loads. With increased uncertainties in the system, it is very important to assess the stability of power systems in a probabilistic framework. Subsequently the most critical uncertainties need to be identified to enable targeted mitigation strategies however these may also change under different operating regimes and for various types of stability concerns. This paper presents a comparative ranking of critical uncertainties using methods with differing computational burdens (Spearman correlation coefficient, Morris method and one-at-a-time approach) for various system stability studies, namely large and small-disturbance rotor angle, frequency and voltage stability. The results show that the most critical parameter varies for different types of stability studies and different penetration levels of RES and demonstrates the benefits of using global sensitivity analysis techniques.