Interval Reliability Evaluation of Hybrid AC/DC Grids With Integrated Renewable Energy

Reliability evaluation of a hybrid AC/DC grid (HADG) with renewable energy is critical because of prevailing uncertainties and complex operations of voltage source converter-based high voltage direct current (DC) transmission. We propose an interval reliability evaluation model to accelerate the speed of HADG reliability evaluation with uncertainties. First, the general nonconvex optimal load shedding (OLS) model is linearized. Second, the linearized OLS model is converted into an interval model, which is decomposed into two bi-level sub-models to quantify the impact of renewable energy uncertainties at HADG. Third, an Average and Scattered Sampling-Adaptive Importance Sampling (AS-AIS) algorithm is proposed to accelerate the convergence of the reliability evaluation. Simulation results for several test systems show the effectiveness and computational tractability of the proposed interval reliability model.