Impact of Load Variability Modelling on Probabilistic Power System Transient Stability

Abstract

Load in a power system is variable due to changes in customer demand. Probability distribution functions (PDFs) are commonly used to model power system load variability. The PDFs are generally selected based on their fit to load density. However, PDFs selected based solely on their fit to load density cannot be guaranteed to model the load range. PDFs that model the load range can synthesise maximum and minimum load values. The ability of PDFs to synthesise maximum and minimum load values ensures that the modelled load can be used to develop the power system peak and minimum demand. In this paper, PDFs are selected based on: (1) having a good fit to load density and (2) their ability to synthesise the load range. The results show that PDFs with a good fit to load density and that also model the load range result in power system transient stability results that are similar to those produced when measured load is used.