Studies of load flow methods in polar and rectangular coordinates

Abstract

This paper presents a study on the performance of load flow methods (in polar and rectangular coordinates) with regard to computation speed, convergence reliability and memory requirements. The load flow techniques in polar coordinates that are studied are the Newton-Raphson and the fast decoupled load flow methods; in rectangular coordinates, the load flow methods considered are the second-order load flow and a decoupled load flow. A modification of the standard fast decoupled load flow for systems with high R/X ratio is also presented and compared. Numerical results were obtained on a 16 MHz, 80386-87 personal computer. Simulations were performed on the IEEE 24-bus reliability test system and the IEEE 118-bus test system. These systems were simulated with several different R/X ratios and under various load conditions.