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Browsing Conference Proceedings by Author "Mvungi, Nerey H."
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Item Agents based service restoration in electrical secondary distribution network(IEEE Xplore, 2019) Mwifunyi, Rukia J.; Mvungi, Nerey H.; Kissaka, Mussa M.Service Restoration (SR) is one of the fundamental functionalities of distribution management system during the fault management process. Several approaches have been devised to solve the SR problem on the distribution network including centralized and distributed approaches. Most of the existing studies focused on the service restoration in the medium voltage network with very few focusing on the Secondary Distribution Network (SDN). In most countries including Tanzania, the service restoration is accomplished manually through relying on operational experiences, rated capacity of the transformers and peak hour demand for decision making. This study aimed at designing a distributed algorithm based on the multiagent system for SR in the SDN. The study has been conducted through intensive literature review together with focus group discussion with key stakeholders from the utility company, study visits to the Tanzania SDN in Dar es Salaam region and interviews with the technical people. SDN with three transformers rated at 315kVA, 200kVA and 100kVA have been chosen as the pilot site for designing the distributed algorithm. The designed algorithm includes designing of multiagent system, objective functions to be optimized and design for the equipment specifications and power system network topology to support SR. Four agents namely, Control Agent, Grid Agent, Load Agent and Switch Agent have been found to be optimal for the SR process. The designed restoration process mainly focuses on load transfer to the nearby transformer and load shedding. The future work will focus on the real implementation of the designed algorithm and consideration of the integration of the renewable distributed generations.Item Short-term load forecasting for improved service restoration in electrical power systems: A case of Tanzania(IEEE, 2020) Mwifunyi, Rukia J.; Kissaka, Mussa M.; Mvungi, Nerey H.Reliable operation of the power system and efficient utilization of its resources requires load demand forecasting in a wide range of time leads, from minutes to several days. Underestimation of load demand forces the power system to operate in a vulnerable region to the disturbance. In the Tanzanian electrical power distribution network, peak hour load demand values are used during service restoration resulting in prolonged load shedding. This study aims at developing a short-term load forecasting model to be used during service restoration for improved service reliability. Several methods have been devised for short-term load forecasting including conventional statistical approaches and data-driven approaches. Data-driven approaches perform well in load forecasting due to its ability in learning features for the dataset with nonlinear characteristics like load demand dataset. The study has adopted an experimental design approach in developing the short-term load foresting model using six years datasets from 2014 to 2019 with twenty minutes resolution from the Tanzania power distribution network. A total of 141,749 datasets were used and three deep learning models namely Long Short-Term Memory (LSTM), Recurrent Neural Network (RNN) and Gated Recurrent Unit (GRU) were used during the experiments. It has been observed that the LSTM outperforms the RNN and GRU with forecasting accuracy of 96.43%. The future work will be the development of a distributed algorithm for service restoration considering stochastic nature of load demand using developed forecasting load model.Item Towards affordable broadband communication: a quantitative assessment of TV white space in Tanzania(Springer Nature, 2017) Matogoro, Jabhera; Mvungi, Nerey H.; Justinian, Anatory; Karandikar, Abhay; Singh, JaspreetA quantitative assessment of TV White Space in Tanzania was conducted to assess the level of spectrum utilization as well as a key milestone towards the use of white space for affordable broadband communication. Two approaches have been used; pollution and protection viewpoints and experimental spectrum measurements based on energy detection principle. The study focused on 470–694 MHz UHF spectrum band which is used for digital terrestrial television in Tanzania. It was found that, more than 120 MHz is available as white space in various locations in Tanzania when pollution and protection view point was used and about 184 MHz are available as white space in Dodoma urban using experimental spectrum measurements and almost 100% of the available frequencies are not used in Dodoma rural. Both approaches revealed that there is low spectrum utilization and therefore presents a best case towards development of dynamic spectrum access technologies in Tanzania