Small-Signal Stability Verification Issues For Transmission Systems With Distributed Renewables

High penetrations of distributed renewables can dramatically increase uncertainty in the transmission system, making small-signal stability verification far more challenging. In this paper, we examine the impact of generating 30% of the power in the IEEE 118 bus test network with 118 distributed renewable sources, and show the inadequacy of sampling approaches to stability analysis. We show that multipoint local optimization can find less stable scenarios that are easily missed by sampling. In addition, we show that stability verification (or certification) is computationally tractable, but as yet, only by linearizing and dimension-reducing the parametric variation.