Probabilistic total transfer capability analysis based on static voltage stability region integrated with a modified distributed-level nodal-loading model

In this paper, a new evaluation method of probabilistic TTC based on SVSR calculation is developed through a hierarchical simulation. A smooth technology based on the non-parametric kernel estimator is adapted to obtain the time-dependent probabilistic density function of the feeder-head load data. In order to describe possible operating change directions of the operating point, the original hyper-cone-like（HCL） model is constructed to consider the probabilistic distribution function（PDF） extracted from feeder-head load data to replace the simple Normal Distribution model and the uncertain generator outputs. To realize the fast TTC calculation of the current operating point in random conditions, a sub-hyper-cone-like（SHCL） model in full power injections space is proposed, which is a similarity transformation of the original one.