A Three-phase Hybrid Power Flow Algorithm for Meshed Distribution System with Transformer Branches and PV Nodes

Abstract

-Aiming at analyzing the power flow of the distribution systems with distribution transformer (DT) branches and PV nodes, a hybrid three-phase power flow methodology is presented in this paper. The incidence formulas among node voltages, loop currents and node current injections have been developed based on node-branch incidence matrix of the distribution network. The method can solve the power flow directly and has higher efficiency. Moreover, the paper provides a modified method to model DT branches by considering winding connections, phase shifting and off-nominal tap ratio, and then DT branches could be seen like one transmission line with the proposed power flow method. To deal with the PV nodes, an improved approach to calculate reactive power increment at each PV node was deduced based on the assumption that the positive-sequence voltage magnitude of PV node is fixed at a given value. Then during calculating the power flow at each iteration, it only needs to update current injection at each PV node with the proposed algorithm. The process is very simple and clear. The results of IEEE 4 nodes and the modified IEEE 34 nodes test feeders verified the correctness and efficiency of the proposed hybrid power flow algorithm.

A Loop-Analysis Theory Based Linear Power Flow Method for Three-Phase Distribution Power System

“…where, Tt is path matrix of 3N * 3N and Bt is loop matrix of 3m * 3N corresponding to the tree branches. The details about T t and B t for three-phase DPS can be found in [23]. ]) be the voltage vector (3N * 1).…”

“…All the algorithms are programmed and realized in MATLAB 2015a (LAPTOP is THINKPAD with Intel Core I3-3110 CPU and 4.00GB Ram). The results from the iterative loop-analysis based full AC power flow method (FACPF) in [23] and [25], are adopted as benchmarks (convergence accuracy is e-6 p.u.). Compared with the Newton-Raphson AC power flow methods and the backward / forward sweep power flow (BFS), FACPF can get the consistent results with the same precision but has much higher calculation efficiency especially for weakly-meshed networks [25].…”

Comparison of solving probabilistic optimal power flow methods in the presence of wind and solar sources

“…It needs two parameters, shape and scale. The Weibull PDF 𝑓 (𝑉 𝑤 ) and the cumulative distribution function (CDF) F(𝑉 𝑤 ) [53] are given as under.…”

The second‐order cone programming method for interval power flow of active distribution network with distributed generation

“…In order to master the operation status of distribution network, studies on solving the power flow problem of the distribution network with distributed generation have become a hot research area currently [7][8][9][10][11][12][13]. The three-phase asymmetrical decoupled power flow of a distribution network with distributed generation has been studied in Refs [8,9], but the output uncertainty of the distributed generation was not taken into account. Considering the Weibull distribution of the wind speed, the probabilistic power flow problem of a distribution network was studied in Ref.…”