An efficient three-phase power flow algorithm for distribution system including PV nodes

The power flow methods used in traditional distribution system will not meet the requirements of distributed generation systems. This paper presents a novel unbalanced three-phase power flow algorithm which fully exploited the special topological structure of radial distribution systems with distributed generation. On the basis of the bath matrix, the sensitivity incident matrix of node voltages and injection currents can be obtained easily, and then a simple direct iterative method in impedance form is developed. The relation between the reactive currents and active currents has been derived based on the characteristic of PV nodes. A new method for handling PV nodes has been proposed. It does not introduce any additional active power at PV nodes and exactly keeps the voltage magnitudes on their scheduled values. In principle, the proposed approach is simple and can be implemented in the existing methods without any difficulties. The validity and effectiveness of the proposed method is demonstrated by the test results of 6-bus and 69-bus systems.