Security Assessment of Power System with Stochastic Uncertainty Based on Steady-state Controllable Distance

Abstract

The increasing penetration of renewable energy makes it more difficult to envelop uncertainty. In this work, a security assessment method is proposed for power system with renewable outputs. The concept of 'controllable distance' is proposed to estimate the security margin from the current renewable output to the boundary of the controllable region, in which the system can securely operate by adjusting the generator outputs. The controllable region is constructed based on the steady-state security region. To ease the computation burden of calculating the controllable distance, a redundant constraints removal algorithm is proposed to simplify the security region and the controllable region. Then, the controllable distance defined on the Euclidean distance can be calculated. Finally, the renewable outputs are modeled based on Itô theory to estimate the time that the system might operate securely. Case studies are performed to demonstrate the feasibility of the proposed method.