  This paper presents an adaptive stochastic spectral embedding (ASSE) method
to solve the probabilistic AC optimal power flow (AC-OPF), a critical aspect of
power system operation. The proposed method can efficiently and accurately
estimate the probabilistic characteristics of AC-OPF solutions. An adaptive
domain partition strategy and expansion coefficient calculation algorithm are
integrated to enhance its performance. Numerical studies on a 9-bus system
demonstrate that the proposed ASSE method offers accurate and fast evaluations
compared to the Monte Carlo simulations. A comparison with a sparse polynomial
chaos expansion method, an existing surrogate model, further demonstrates its
efficacy in accurately assessing the responses with strongly local behaviors.
