Probabilistic Load Flow Computation Using the Method of Combined Cumulants and Gram-Charlier Expansion

TLDR

Open‑access transmission has created a deregulated power market and introduced new challenges to system planning. The study proposes a probabilistic load‑flow method to serve as a quick screening tool for identifying major investments to improve transmission system adequacy. The method combines cumulants and Gram‑Charlier expansion theory to generate probabilistic distribution functions of transmission line flows. It markedly reduces computational time while preserving high accuracy, enabling objective probabilistic analysis and quantitative reliability assessment of power‑flow problems.

Abstract

Open access transmission has created a deregulated power market and brought new challenges to system planning. This paper proposes a new method to compute a probabilistic load flow in extensive power systems for the purpose of using it as a quick screening tool to determine the major investment on improving transmission system inadequacy. This innovative method combines the concept of Cumulants and Gram-Charlier expansion theory to obtain probabilistic distribution functions of transmission line flows. It has significantly reduced the computational time while maintaining a high degree of accuracy. This enables probabilistic analysis of power flow problems to be treated objectively and allows quantitative assessment of system reliability.