INVESTIGATION AND MITIGATION OF UNDER VOLTAGE PROBLEMS IN DISTRIBUTION NETWORK BY OPTIMAL PLACEMENT OF CAPACITOR BANKS (A Case study at Adama Distribution System)

Abstract

Distribution feeders are components of distribution system which transfer power from distribution substation to distribution transformers located near to customer’s premises. Distribution substation feeders which have poor power factor, large loads beyond it’s’ carrying capacity and which travel long distance to feed costumers are not efficient in transferring electrical power to the connected costumers. To improve the efficiency of distribution feeders voltage profile improvement techniques are required. Adama distribution substation is one of the distribution substations found in Oromia electric utility which has Eleven (11) outgoing feeders that feed different areas of Adama town. Among these feeders, feeder four F1 has been selected as test system after investigation has been done through distribution interruption due to over load regarding all outing feeders from 2018 to 2020 years recorded data. The selected feeder has been modeled in ETAP software with built in a genetic algorithm and load flow analysis has been simulated using Newton-Raphson method that is built in ETAP software. The proposed method was tested on distribution system of Adama outgoing Feeder-1. In the tested distribution system it was found that by placing total of 9000kvar at a location (bus-4, bus-8 and bus-13). After capacitor bank installed on the feeder -1 near bus -4; bus 8 and bus 13 the voltage drop improvement from 14.085 to 15.005 with a percentage increment of 6.13%; from 14.050 to 15.020 with a percentage increment of 6.46% and from 14.090 to 15.011 with a percentage increment of 6.12% consecutively. And also total power loss to decrease from 0.253MW to 0.137MW. Due to this, the Ethiopian Electric Utility can save 143,731.68 Birr per annum with the payback period of Eighteen months. In general, Optimal Capacitor Placement in Adama distribution network feeder -1 averagely improves voltage profile of the feeder with 6.10% and as a result it enhanced the power quality of the distribution network.