APPLICATION OF FORWARD – BACKWARD PROPAGATION ALGORITHM FOR THREE – PHASE POWER FLOW ANALYSIS IN RADIAL DISTRIBUTION SYSTEM

Abstract

Power flow analysis is backbone of power system analysis and design. It is essential for power system analysis in operational as well as in planning stages. Power flow calculation is normally performed by simply considering that the system under study is completely balance. Actual distribution system is inherently unbalance and therefore three-phase power flow is necessary to accurately simulate the unbalance system. However, inclusion of unbalance increases the dimension of problem and, as distribution system is commonly constructed as radial system with high R/X ratio, it may also cause the sophisticated power flow algorithms fail to converge. The robust algorithm for three-phase power flow is therefore needed. In this paper, three-phase power flow for unbalance distribution system is carried out using Forward-Backward Propagation Technique. The equivalent injection current method is employed to represent the loads and shunt admittances. The algorithm starts with mapping the distribution network to determine the forward and backward propagation paths. The backward propagation is used to calculate branch currents using the bus injection currents. The forward propagation is employed to calculate bus voltages using the obtained branch currents and line impedances. The algorithm offers robust and good convergence characteristics for radial distribution system. The algorithm is presented for the IEEE 34-bus system with satisfied generated results.