On polynomial real-time control policies in stochastic AC optimal power flow

Abstract In traditional power system operations real-time control policies are based on simple control policies such as automatic generation control and/or local voltage control. Although these simple policies have worked well in the past, the increased variability associated with higher penetrations of renewable energy strengthens the case for more general approaches. In this paper we analyze the design of real-time control policies through the lens of stochastic AC-OPF. Using a chance-constrained approach in combination with a reformulation based on polynomial chaos expansion, we show that the solution corresponds to a general polynomial control policy. By restricting this general policy, we are able to recover the traditional (affine) control policies as a special case. This allows to quantify the value of implementing non-affine policies, and to analyze their impact on the system behavior, as demonstrated in the numerical example.