ABSTRACT:
Three-phase distribution networks are traditionally modeled in phase coordinates frame of reference.
This is because the mutual inductances between different phases of an asymmetrical transmission lines
are not equal to each other. Besides the sequence networks are coupled together and cannot be broken
into independent circuits and distribution systems contain multi-phase unbalanced laterals. A variety of
three-phase power-flow algorithms have been developed based on phase components for solving
unbalanced power systems. Some of these algorithms solve a general network structure such as
standard Newton Raphson method or its variants [1-5]. However, the three-phase Newton- Raphson
method is computationally expensive for large systems due to the size of the Jacobian matrix and its fast
decoupled version is sensitive for high line R/X ratios. The admittance or impedance methods [6-9] have
convergence characteristics that are highly dependent on the number of the PV nodes in electrical
network [8]. There are also unbalanced power-flow methods which consider primarily the radial
structure of distribution networks. Therefore, these power-flow methods can solve only radial or weekly
meshed systems such as methods given in [10-11].