Nanogrid sizing using nested integer linear programming and time-of-use based load management

Electrical utility services are evolving from centralized conventional systems to distributed grids (DGs) attributing to clean energy production, customer participation and low energy cost. Integration of renewable energy (RE) systems into existing grids results in complex grid structure which requi...

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Main Author: Dahiru, Ahmed Tijjani
Format: Thesis
Language:English
Published: 2021
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Online Access:http://eprints.utm.my/id/eprint/102496/1/AhmedTijjaniDahiruPSKE2021.pdf.pdf
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spelling my-utm-ep.1024962023-08-29T06:46:36Z Nanogrid sizing using nested integer linear programming and time-of-use based load management 2021 Dahiru, Ahmed Tijjani TK Electrical engineering. Electronics Nuclear engineering Electrical utility services are evolving from centralized conventional systems to distributed grids (DGs) attributing to clean energy production, customer participation and low energy cost. Integration of renewable energy (RE) systems into existing grids results in complex grid structure which requires optimization methods in planning and operational schemes. In RE system planning, capacity sizing and component placements are typically implemented using classical methods, application software and intelligent-based methods. The software-based methods are static, hence, cannot be tuned to a customized application. Whereas, intelligent-based methods produce results that are acceptable, however, not optimal. Linear programming (LP) based algorithms as classical methods are preferred due to its simplicity, speed and accuracy which yields global optimal results without branching at local solutions. The mixed integer linear programming (MILP) is used in microgrid’s components sizing. However, MILP has limitations of large formulations, high computational burdens and hardly consider multi-objective analysis. To overcome the MILP problems, nested integer linear programming (NILP) is proposed in this study to implement a multi-configurational sizing in residential nanogrid to achieve low energy cost. A residential located in sub-Saharan semiarid climates of northern Nigeria is chosen as a case study. The proposed NILP is implemented in a multi-stage hybridization of relaxation LP and MILP in a nested loop for nanogrid configurations using photovoltaic (PV), wind turbine (WT) and battery energy storage system (BESS). Effectiveness of the NILP is verified by comparison with the classical MILP and particle swarm optimization (PSO). Operation schemes in RE systems include power dispatch and demand side management (DSM). The DSM is preferred as it allows more options for customer participation and can simply follow supplies. DSM is implemented using the conventional time-of-use (CTOU) methods. However, the CTOU is time-bound, utility-centred, incur additional energy costs and affects customer comforts. To balance the conflicting objectives of energy cost and customer comfort, the time-of-use fitness (TOUF) which is an improved version of CTOU has been proposed. The method is introduced to achieve load management for the nanogrid’s optimal energy utilization and to reduce consumption cost. The proposed TOUF considered local RE supplies, BESS, grid interaction and customer demands based on a fitness function (Ffunction). The Ffunction is a demand response initiative used alternately for energy based on real-time energy cost to define a fitness costs (Fcost) as the energy consumption cost. Both the sizing and load management schemes are implemented using MATLAB programming. The NILP achieved reductions in nanogrid’s capacity, the levelized cost of energy (LCOE), and net present costs (NPC) as compared to the MILP. The PV/WT hybrid nanogrid configuration achieves NPC and LCOE reductions by 11% and 33% compared to MILP and PSO, respectively. The TOUF achieved up to 43.40% and 53.09% Fcost reductions under the BESS support. The autonomous nanogrid operations were analysed using the Markov Chains as a stochastic tool. The probabilistic information indicates thAat the proposed nanogrid is able to achieve up to 61.54% autonomy in a 25-year lifetime analysis. 2021 Thesis http://eprints.utm.my/id/eprint/102496/ http://eprints.utm.my/id/eprint/102496/1/AhmedTijjaniDahiruPSKE2021.pdf.pdf application/pdf en public http://dms.library.utm.my:8080/vital/access/manager/Repository/vital:149171 masters Universiti Teknologi Malaysia Faculty of Engineering - School of Electrical Engineering
institution Universiti Teknologi Malaysia
collection UTM Institutional Repository
language English
topic TK Electrical engineering
Electronics Nuclear engineering
spellingShingle TK Electrical engineering
Electronics Nuclear engineering
Dahiru, Ahmed Tijjani
Nanogrid sizing using nested integer linear programming and time-of-use based load management
description Electrical utility services are evolving from centralized conventional systems to distributed grids (DGs) attributing to clean energy production, customer participation and low energy cost. Integration of renewable energy (RE) systems into existing grids results in complex grid structure which requires optimization methods in planning and operational schemes. In RE system planning, capacity sizing and component placements are typically implemented using classical methods, application software and intelligent-based methods. The software-based methods are static, hence, cannot be tuned to a customized application. Whereas, intelligent-based methods produce results that are acceptable, however, not optimal. Linear programming (LP) based algorithms as classical methods are preferred due to its simplicity, speed and accuracy which yields global optimal results without branching at local solutions. The mixed integer linear programming (MILP) is used in microgrid’s components sizing. However, MILP has limitations of large formulations, high computational burdens and hardly consider multi-objective analysis. To overcome the MILP problems, nested integer linear programming (NILP) is proposed in this study to implement a multi-configurational sizing in residential nanogrid to achieve low energy cost. A residential located in sub-Saharan semiarid climates of northern Nigeria is chosen as a case study. The proposed NILP is implemented in a multi-stage hybridization of relaxation LP and MILP in a nested loop for nanogrid configurations using photovoltaic (PV), wind turbine (WT) and battery energy storage system (BESS). Effectiveness of the NILP is verified by comparison with the classical MILP and particle swarm optimization (PSO). Operation schemes in RE systems include power dispatch and demand side management (DSM). The DSM is preferred as it allows more options for customer participation and can simply follow supplies. DSM is implemented using the conventional time-of-use (CTOU) methods. However, the CTOU is time-bound, utility-centred, incur additional energy costs and affects customer comforts. To balance the conflicting objectives of energy cost and customer comfort, the time-of-use fitness (TOUF) which is an improved version of CTOU has been proposed. The method is introduced to achieve load management for the nanogrid’s optimal energy utilization and to reduce consumption cost. The proposed TOUF considered local RE supplies, BESS, grid interaction and customer demands based on a fitness function (Ffunction). The Ffunction is a demand response initiative used alternately for energy based on real-time energy cost to define a fitness costs (Fcost) as the energy consumption cost. Both the sizing and load management schemes are implemented using MATLAB programming. The NILP achieved reductions in nanogrid’s capacity, the levelized cost of energy (LCOE), and net present costs (NPC) as compared to the MILP. The PV/WT hybrid nanogrid configuration achieves NPC and LCOE reductions by 11% and 33% compared to MILP and PSO, respectively. The TOUF achieved up to 43.40% and 53.09% Fcost reductions under the BESS support. The autonomous nanogrid operations were analysed using the Markov Chains as a stochastic tool. The probabilistic information indicates thAat the proposed nanogrid is able to achieve up to 61.54% autonomy in a 25-year lifetime analysis.
format Thesis
qualification_level Master's degree
author Dahiru, Ahmed Tijjani
author_facet Dahiru, Ahmed Tijjani
author_sort Dahiru, Ahmed Tijjani
title Nanogrid sizing using nested integer linear programming and time-of-use based load management
title_short Nanogrid sizing using nested integer linear programming and time-of-use based load management
title_full Nanogrid sizing using nested integer linear programming and time-of-use based load management
title_fullStr Nanogrid sizing using nested integer linear programming and time-of-use based load management
title_full_unstemmed Nanogrid sizing using nested integer linear programming and time-of-use based load management
title_sort nanogrid sizing using nested integer linear programming and time-of-use based load management
granting_institution Universiti Teknologi Malaysia
granting_department Faculty of Engineering - School of Electrical Engineering
publishDate 2021
url http://eprints.utm.my/id/eprint/102496/1/AhmedTijjaniDahiruPSKE2021.pdf.pdf
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