Power Loss Reduction and Voltage Profile Improvement of Distribution Feeder (Case study: Hawassa Substation Distribution Feeder 7)

Abstract

Power quality issues, mainly voltage sag, are the major problem inside the distribution network. Further, losses also create serious concerns in the power distribution. As a result, in this work, capacitors are optimally placed using the Genetic Algorithm (GA) to mitigate voltage sag and power losses. A practical data set from Hawassa substation, which has nine 15kV outgoing feeders and four 33kV outgoing feeders, is being utilized to show the implementation of the proposed work. From those 15kV outgoing lines, feeders 7, 5, 8, 4, 3, 6, 2, 9 and 1 have high power loss and voltage drop respectively from load flow results. Feeder 7 is selected from this work due to its high power loss compared to the rest of the feeder by load flow analysis. This feeder has been modeled in ETAP software and Newton Raphson load flow is performed. From load flow simulation of feeder 7, it has been seen that the feeder has a power loss of 0.472MW. The objective function of this thesis work is to minimize power loss, improve voltage profile and power factor with minimum investment cost. This is achieved by optimal capacitor placement for reactive power compensation of the network. The operation of the capacitor bank is done by the CQ930 automatic capacitor controller, which provides a reliable method of monitoring and switching. By using GA, the power loss is improved from 0.472MW to 0.276MW, the minimum voltage magnitude is improved from 90.24% to 95.62%, and the power factor is improved from 87.35% to 90.49%, and finally, the system capacity is increased from 2.612MVA to 3.152MVA. Due to this overall improvement in the network, EEU can save $39,707.22 while the total investment cost is 63,200 with a payback period of seven months