Study of causes of poor quality in Tanesco distribution system: case study of Temeke region.

Tanzania Electric Supply Company (TANESCO) has been the only power utility company in Tanzania responsible for generation, transmission and distribution of electric power to consumers. However the quality of electrical power supplied by Tanesco to its customers is very poor due to the presence of voltage fluctuation, power interruption and severe distribution power losses. In this research a part of Temeke distribution network has been chosen as a case study because of its poor power quality supplied to its customers, since their low voltage is below standard. The distribution network is overloaded and experiences severe distribution power losses. In general is in poor condition, it is unable to handle power demand in the area and supply the consumer with electricity of acceptable quality. Some measurements and data taking on the selected distribution network have been done in order to be used to study the causes of poor power quality supplied to consumers. The distribution network has been analyzed by using SIMPOW simulation software developed by ABB- Sweden. From the load flow simulation and dynamic simulation results of the existing network, it was observed that there were problems of overloading of distribution transformers and distribution lines, distribution power losses, voltages below permissible levels for some load points, phase unbalances and phase mixing. By changing the overloaded transformers and distribution lines to the required ratings the load flow simulation and dynamic simulation was performed and the results showed that the network conditions were improved since all transformers and distribution lines were operated within the rated values. The distribution power losses were reduced by 20% and the voltages at the load points were improve. Lastly it was recommended that the single phase loads be redistributed to alleviate the unsymmetry and phase mix up at the distribution transformer should be eliminated