Improvements on usual load flow algorithms of power system

This paper makes several improvements on usual load flow algorithms of power system. The first improvement is that this paper presents a treatment method of multi-swing buses based on the Norton equivalence. The method can not only be used to calculate single network's load flow with multi-swing bused in it, but also be used to calculate several different network load flow with multi-swing buses in each network. The second improvement is that this paper presents a treatment method of small- or zero-impedance lines based on the bus equivalent additional injections of these lines. The method can make the bus admittance matrix be benign, which guarantees high-speed and accuracy of algorithm. The third improvement is that this paper presents an adapted PQ de-coupled load flow algorithm, which solves the problem of astringency sensitivity to great R/X ration of line parameters. The method can not only be used to transmission systems, but also be used to distribution systems.