Fast Decoupled Load Flow

TLDR

The method is a development on recent MW‑Θ/ MVAR‑V decoupling work, refined through extensive numerical studies. The paper presents a simple, reliable, and extremely fast load‑flow solution, detailing its performance on practical problems up to 1080 buses. Built on the MW‑Θ/ MVAR‑V decoupling principle, the method is a simple, reliable, and extremely fast load‑flow solution whose performance on practical problems up to 1080 buses is detailed. The method delivers accurate or approximate off‑ and on‑line routine and contingency calculations for networks of any size, achieving solutions within 0.01 MW/MVAR mismatches in 4–7 iterations—each as fast as 1½ Gauss‑Seidel or 1/5th Newton iterations—and reveals useful correlations between convergence criteria and actual accuracy.

Abstract

This paper describes a simple, very reliable and extremely fast load-flow solution method with a wide range of practical application. It is attractive for accurate or approximate off-and on-line routine and contingency calculations for networks of any size, and can be implemented efficiently on computers with restrictive core-store capacities. The method is a development on other recent work employing the MW-Θ/ MVAR-V decoupling principle, and its precise algorithmic form has been determined by extensive numerical studies. The paper gives details of the method's performance on a series of practical problems of up to 1080 buses. A solution to within 0.01 MW/MVAR maximum bus mismatches is normally obtained in 4 to 7 iterations, each iteration being equal in speed to 1½ Gauss-Seidel iterations or 1/5th of a Newton iteration. Correlations of general interest between the power-mismatch convergence criterion and actual solution accuracy are obtained.