Power Engineering

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Browsing Power Engineering by Author "Abrham, Workie"

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    Studies on Transmission Expansion planning (Case study: Addis Ababa Transmission System)
    (Addis Ababa University, 2019-04) Abrham, Workie; N.P., Singh (PhD)
    Load forecasting is the prediction of demand for the future period and is an essential requirement for planning and expansion of power systems. In this thesis, load forecast for Addis Ababa Region Transmission System is obtained for the period of 2018 to 2022 and transmission system expansion planning is carried out to meet the forecasted load. Load forecasting is carried out using MS Excel software and following the general stochastic regression techniques. Two independent variables, namely - GDP and number of customers are considered as the main factors affecting the future load growth. Load forecasting is carried out using MS Excel software and following the general stochastic regression techniques. The load forecast for the year 2018 is 991.91MW, that for the year is 2019 is 1063.00MW, the same for the year 2020 is 1169.42MW, while the same for the years 2021 and 2022 is found to be 1206.13MW 1269.83MW, respectively. Network modeling using ETAP software is done for expansion planning and simulation studies. All the necessary data are collected and power system network elements has been modeled using the software. The model includes the overall power system equipment of Addis Ababa area with their arrangement for analysis and simulation purpose. Simulation studies including Load flow analysis, short circuit analysis and transient stability analysis have been carried out using the ETAP software for the existing system and the proposed expanded system. From the simulation results, it is found that 9 out of 35 transmission lines are overloaded, 42 out of 71 transformers are overloaded, while 16 out of 31 buses face under voltage problems while meeting the future load demands. It is further observed that that maximum transmission line overloading happens in the year 2022 on Minilik – Gefersa 132kV transmission line and maximum transformer overloading occurs for the load during 2022 on Sebeta I TR3. It is also found that the Addis south II bus is 86.4% below the nominal voltage range. Simulation studies have been further carried out to test the performance of the expanded Addis Ababa Region Transmission System and compare the results with the existing transmission system to meet the future loads for the period 2018-2022. From the simulation results, it is observed that for the proposed expanded transmission system, the transmission lines overloading improves from 152.23% to 63.6% and transformer overloading improves from 335.14% to 82.8%. Also, with the proposed capacitor placement, the bus voltage improves to 97.13% while meeting the future loads. Therefore, it is recommended that EEP may go for implementation of the proposed expansion plan.