LAYER-BY-LAYER BACK/FORWARD SWEEP METHOD FOR RADIAL DISTRIBUTION LOAD FLOW

Based on special hiberarchy characteristic of radial network, this paper proposed a novel layer-by-layer back/forward sweep distribution load flow algorithm. In this algorithm, the branches of network are sorted by layers and the loss of voltage and power of branches in the same layer can be parallel computed, so the speed of power flow can be increased greatly. In this paper, this algorithm is realized by making full use of fast plural matrix operation function of MATLAB, and the increase of that speed is also outstanding. Furthermore, It is testified in this paper that the large shunt conductance will bring on the convergence problem of distribution load flow, which is produced by theΠ equivalent model when the impedance of transformer branch is too small. For solving this problem, an effective equivalent model of voltage transforming is proposed according to the principle for ideal transformer to transform voltage and power. In two power systems, the IEEE40 bus system and a 1338 bus actual power system, the proposed method has been tested. The results indicate that it has faster speed and more reliable convergence.