A COMPUTER CALCULATION FOR TENTATIVE ELECTRICAL SYSTEM IMPROVEMENT BY REACTIVE POWER COMPENSATION CONSIDERING SYSTEM UNBALANCED

Abstract

An improvement of unbalanced distribution system operation is carried out by reactive power compensation. The lagging reactive power demand is compensated by allocating a number of three-phase shunt capacitors. At the stage, the compensation devices are determined tentatively in term of number, size and location. The effects of the installed shunt capacitors are then analyzed. The unbalanced condition of distribution system is taken into account due to the fact that distribution system is inherently imbalance. For three-phase unbalanced power flow analyses, forward-backward propagation algorithm is proposed. The algorithm works directly on the system without any modification. Starting with determination of forward and backward propagation paths, the algorithm calculates branch currents using backward path. With the branch currents in hand, the bus voltages are calculated using the obtained branch currents and line impedances. Equivalent injection currents representing loads and shunt admittances method are required. The algorithm offers robust and good convergence characteristics for radial distribution system. In this paper, reactive power compensation is simulated using tentative approach and the achieved system improvements are observed. The improvements are presented as losses minimization and voltage profile enhancement. The simulation is carried out for the IEEE 34-bus system, while the system improvements due system compensation are described. The generated results indicate that for further optimal system improvement, an optimization technique is required