Search results for " load flow."
showing 7 items of 17 documents
Simple measures to improve the performances of the backward/forward method for radial distribution network analysis
2005
In the paper, after having presented the general backward/forward methodology for radial systems analysis, the main changes that have been proposed in the past to improve their convergence and speed performance are shown. Some measures aimed at a further reduction of the number of iterations and calculation times are here described. In order to identify, among the available alternatives, the best methodology, in terms of precision and/or speed of convergence, some evaluations on networks taken from the literature have been carried out. The analysis of the attained results allows the definition, on the basis of specific features of the problem at hand, the most suitable configuration to be i…
An Efficient Procedure for Solving Radial Distribution Networks through the Backward/Forward Method
2005
In the paper, after having presented the general backward/forward methodology for radial systems analysis, a new b/f procedure showing some interesting features that improve its performance in terms of convergence speed and calculation effort is presented. The features that fundamentally are responsible for such improvements concern the main steps of the b/f procedure. The starting voltage profile solution is different from the flat profile and is suitably modified. In the backward phase and starting from the second iteration, the branch currents variations due to the loads changes are evaluated; the latter variations are calculated on the basis of the difference of nodal voltages at the be…
Load flow analysis of radial distribution networks: New findings in backward/forward method
2005
In the paper, the backward/forward method for solving radial distribution networks is in details described. In particular it is examined considering the four main steps into which it can be divided: initialization of the state variables; backward sweep; forward sweep; identification of a convergence criterion. For each of these, except for the forward sweep, a new procedure is defined. In particular, a methodology for the identification of a starting solution that is as close as possible to the desired one is proposed; the backward phase is modified for the evaluation of the branch currents and a new convergence criterion is proposed. The results of the application of the proposed methodolo…
A Backward Method for Solving PV Nodes in Weakly Meshed Distribution Networks
2007
In this paper, a new iterative backward/forward methodology for the load flow solution of weakly meshed systems with fixed voltage nodes is presented. Such technique models the loads at each iteration by means of impedances, and the PV nodes by means of reactances. Each iteration is organised in two steps. In the first, the radial network attained from the meshed system through cuts and composed of shunt and series impedances is solved. In the second step, based on a reduced Thévenin impedance matrix, the compensation currents to be injected in the cut nodes are deduced. Modelling the PV nodes by means of reactances allows the attainment, for the reactive power of these nodes, of the same p…
An analytical model for PQ sources in backward/forward methods for distribution networks analysis
2004
In this paper a model of PQ sources useful for distribution systems analysis is developed. In the considered systems there are, in addition to HV/MV sources, other PQ buses, namely active and reactive power supply nodes (Vδ nodes). The general solution strategy is an iterative forward/backward method, in which the state variables are the node voltages. If it is weakly meshed, the network is turned into radial by means of cuts and compensation currents. After the presentation of the general problem, the equations expressing the unknowns for the PQ nodes are treated in detail. These equations belong to the backward sweep of the algorithm. The methodology has been implemented and applied so as…
A new model of PV nodes in distribution networks backward/forward analysis
2004
In this paper a new model of PV nodes is developed; the model is aimed for the distribution systems load flow analysis and, in particular, for the iterative forward/backward method. If the network is weakly meshed, it is turned into radial by means of cuts and compensation currents. After the presentation of the general problem and the state of the art on the subject, the equations expressing the unknowns for the PV nodes are treated in detail. These equations belong to the forward sweep of the algorithm. The methodology has been implemented and applied so as to test its performance in terms of calculation times and precision. The obtained results confirm the efficiency of the proposed appr…
A Multi-Port Approach to Solve Distribution Networks with Meshes and PV Nodes
2007
A new methodology based on the backward/forward (b/f) technique for the load flow solution in distribution systems is here proposed. The methodology takes efficiently into account the fixed voltage nodes and uses a reduced bus impedance matrix. In this way, it is possible to attain, for the unknowns at the PV nodes, the same values that are attainable solving the network with the methods adopted for transmission systems. With the same methodology it is possible to take into account also the meshes. If the network contains only meshes, the relevant model is linear and it is the one including the compensation currents. The presence of PV nodes introduces non linearity in the model and an iter…