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Dr. Walter Julián Gil-González
Institución Universitaria Pascual Bravo

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0 Convex Optimization
0 Power Converters
0 passive control
0 Power System Control
0 Electrical & Electronics Engineering

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Convex Optimization
Power Converters
passive control

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Journal article
Published: 30 June 2021 in IEEE Latin America Transactions
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This paper addresses the problem of parametric estimation in solar cells considering manufacturer datasheet information regarding open-circuit, short-circuit, and maximum power points from the point of view of mathematical optimization. To represent this problem a single-objective function is formulated associated with the minimization of the mean square error of the single-diode model evaluated in the operational points reported by the manufacturer. The solution of this nonlinear non-convex optimization model is addressed with a metaheuristic optimization technique known in specialized literature as a vortex search algorithm (VSA). This metaheuristic optimization method works with Gaussian distribution functions and variable radius to explore and exploit the solution space by generating hyperspheres that move through the solution space as a function of the best current solution. The VSA is implemented in MATLAB environment by using commercial photovoltaic module information, where numerical results demonstrate the efficiency of this optimization method with objective functions lower than 1times10-25 and processing times around 6.13s.

ACS Style

Oscar Danilo Montoya; Walter Julian Gil-Gonzalez; Jesus Maria Lopez-Lezama. Vortex Search Algorithm Applied to the Parametric Estimation in PV Cells Considering Manufacturer Datasheet Information. IEEE Latin America Transactions 2021, 19, 1581 -1589.

AMA Style

Oscar Danilo Montoya, Walter Julian Gil-Gonzalez, Jesus Maria Lopez-Lezama. Vortex Search Algorithm Applied to the Parametric Estimation in PV Cells Considering Manufacturer Datasheet Information. IEEE Latin America Transactions. 2021; 19 (9):1581-1589.

Chicago/Turabian Style

Oscar Danilo Montoya; Walter Julian Gil-Gonzalez; Jesus Maria Lopez-Lezama. 2021. "Vortex Search Algorithm Applied to the Parametric Estimation in PV Cells Considering Manufacturer Datasheet Information." IEEE Latin America Transactions 19, no. 9: 1581-1589.

Research article electrical engineering
Published: 23 June 2021 in Arabian Journal for Science and Engineering
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In this study, we present a master–slave methodology to solve the problem of optimal power dispatch in a direct current (DC) microgrid. In the master stage, the Antlion Optimization (ALO) method solves the problem of power dispatch by the Distributed Generators (DGs); in the slave stage, a numerical method based on successive approximations (SA) evaluates the load flows required by the potential solutions proposed by the ALO technique. The objective functions in this paper are the minimization of energy production costs and the reduction of \(\hbox {CO}_2\) emissions produced by the diesel generators in the microgrid. To favor energy efficiency and have a lower negative impact on the environment, the DC microgrids under study here include three DGs (one diesel generator and two generators based on renewable energy sources, i.e., solar energy and wind power) and a slack bus connected to a public electrical grid. The effectiveness of the proposed ALO–SA methodology was tested in the 21- and 69-bus test systems. We used three other optimization techniques to compare methods in the master stage: particle swarm optimization, continuous genetic algorithm, and black hole optimization. Additionally, we combined SA with every method to solve the load flow problem in the slave stage. The results show that, among the methods analyzed in this study, the proposed ALO–AS methodology achieves the best performance in terms of lower energy production costs, less \(\hbox {CO}_2\) emissions, and shorter computational processing times. All the simulations were performed in MATLAB.

ACS Style

J. A. Ocampo-Toro; O. D. Garzon-Rivera; L. F. Grisales-Noreña; O. D. Montoya-Giraldo; W. Gil-González. Optimal Power Dispatch in Direct Current Networks to Reduce Energy Production Costs and $$\hbox {CO}_2$$ Emissions Using the Antlion Optimization Algorithm. Arabian Journal for Science and Engineering 2021, 1 -12.

AMA Style

J. A. Ocampo-Toro, O. D. Garzon-Rivera, L. F. Grisales-Noreña, O. D. Montoya-Giraldo, W. Gil-González. Optimal Power Dispatch in Direct Current Networks to Reduce Energy Production Costs and $$\hbox {CO}_2$$ Emissions Using the Antlion Optimization Algorithm. Arabian Journal for Science and Engineering. 2021; ():1-12.

Chicago/Turabian Style

J. A. Ocampo-Toro; O. D. Garzon-Rivera; L. F. Grisales-Noreña; O. D. Montoya-Giraldo; W. Gil-González. 2021. "Optimal Power Dispatch in Direct Current Networks to Reduce Energy Production Costs and $$\hbox {CO}_2$$ Emissions Using the Antlion Optimization Algorithm." Arabian Journal for Science and Engineering , no. : 1-12.

Journal article
Published: 26 May 2021 in Applied Sciences
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Transportation electrification has demonstrated a significant position on power utilities and logistic companies, in terms of assets operation and management. Under this context, this paper presents the problem of seeking feasible and good quality routes for electric light commercial vehicles considering battery capacity and charging station siting on the power distribution system. Different transportation patterns for goods delivery are included, such as the capacitated vehicle routing problem and the shortest path problem for the last mile delivery. To solve the problem framed within a mixed integer linear mathematical model, the GAMS software is used and validated on a test instance conformed by a 19-customer transportation network, spatially combined with the IEEE 34 nodes power distribution system. The sensitivity analysis, performed during the computational experiments, show the behavior of the variables involved in the logistics operation, i.e., routing cost for each transport pattern. The trade-off between the battery capacity, the cost of the charging station installation, and energy losses on the power distribution system is also shown, including the energy consumption cost created by the charging operation.

ACS Style

Andrés Arias-Londoño; Walter Gil-González; Oscar Montoya. A Linearized Approach for the Electric Light Commercial Vehicle Routing Problem Combined with Charging Station Siting and Power Distribution Network Assessment. Applied Sciences 2021, 11, 4870 .

AMA Style

Andrés Arias-Londoño, Walter Gil-González, Oscar Montoya. A Linearized Approach for the Electric Light Commercial Vehicle Routing Problem Combined with Charging Station Siting and Power Distribution Network Assessment. Applied Sciences. 2021; 11 (11):4870.

Chicago/Turabian Style

Andrés Arias-Londoño; Walter Gil-González; Oscar Montoya. 2021. "A Linearized Approach for the Electric Light Commercial Vehicle Routing Problem Combined with Charging Station Siting and Power Distribution Network Assessment." Applied Sciences 11, no. 11: 4870.

Journal article
Published: 11 May 2021 in Resources
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The problem of the optimal placement and sizing of photovoltaic power plants in electrical power systems from high- to medium-voltage levels is addressed in this research from the point of view of the exact mathematical optimization. To represent this problem, a mixed-integer nonlinear programming model considering the daily demand and solar radiation curves was developed. The main advantage of the proposed optimization model corresponds to the usage of the reactive power capabilities of the power electronic converter that interfaces the photovoltaic sources with the power systems, which can work with lagging or leading power factors. To model the dynamic reactive power compensation, the η-coefficient was used as a function of the nominal apparent power converter transference rate. The General Algebraic Modeling System software with the BONMIN optimization package was used as a computational tool to solve the proposed optimization model. Two simulation cases composed of 14 and 27 nodes in transmission and distribution levels were considered to validate the proposed optimization model, taking into account the possibility of installing from one to four photovoltaic sources in each system. The results show that energy losses are reduced between 13% and 56% as photovoltaic generators are added with direct effects on the voltage profile improvement.

ACS Style

Andrés Buitrago-Velandia; Oscar Montoya; Walter Gil-González. Dynamic Reactive Power Compensation in Power Systems through the Optimal Siting and Sizing of Photovoltaic Sources. Resources 2021, 10, 47 .

AMA Style

Andrés Buitrago-Velandia, Oscar Montoya, Walter Gil-González. Dynamic Reactive Power Compensation in Power Systems through the Optimal Siting and Sizing of Photovoltaic Sources. Resources. 2021; 10 (5):47.

Chicago/Turabian Style

Andrés Buitrago-Velandia; Oscar Montoya; Walter Gil-González. 2021. "Dynamic Reactive Power Compensation in Power Systems through the Optimal Siting and Sizing of Photovoltaic Sources." Resources 10, no. 5: 47.

Journal article
Published: 30 April 2021 in Electric Power Systems Research
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This paper presents a model for stabilizing multi-terminal high voltage direct-current (MT-HVDC) networks with constant power terminals (CPTs) interfaced with power electronic converters. A hierarchical structure of hierarchical control is developed, which guarantees a stable operation under load variations. This structure includes a port-Hamiltonian formulation representing the network dynamics and a passivity-based control (PBC) for the primary control. This control guarantees stability according to Lyapunov’s theory. Next, a convex optimal power flow formulation based on semidefinite programming (SDP) defines the control’s set point in the secondary/tertiary control. The proposed stabilization scheme is general for both point-to-point HVDC systems and MT-HVDC grids. Simulation results in MATLAB/Simulink demonstrate the stability of the primary control and the optimal performance of the secondary/tertiary control, considering three simulation scenarios on a reduced version of the CIGRE MT-HVDC test system: (i) variation of generation and load, (ii) short-circuit events with different fault resistances and (iii) grid topology variation. These simulations prove the applicability and efficiency of the proposed approach.

ACS Style

Oscar Danilo Montoya; Walter Gil-González; Alejandro Garces; Federico Serra; Jesus C. Hernández. Stabilization of MT-HVDC grids via passivity-based control and convex optimization. Electric Power Systems Research 2021, 196, 107273 .

AMA Style

Oscar Danilo Montoya, Walter Gil-González, Alejandro Garces, Federico Serra, Jesus C. Hernández. Stabilization of MT-HVDC grids via passivity-based control and convex optimization. Electric Power Systems Research. 2021; 196 ():107273.

Chicago/Turabian Style

Oscar Danilo Montoya; Walter Gil-González; Alejandro Garces; Federico Serra; Jesus C. Hernández. 2021. "Stabilization of MT-HVDC grids via passivity-based control and convex optimization." Electric Power Systems Research 196, no. : 107273.

Journal article
Published: 25 April 2021 in Electronics
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This paper proposes adaptive virtual inertia for the synchronverter model implemented in a wind turbine generator system integrated into the grid through a back-to-back converter. A linear dynamic system is developed for the proposed adaptive virtual inertia, which employs the frequency deviation and the rotor angle deviation of the synchronverter model as the state variables and the virtual inertia and frequency droop gain as the control variables. In addition, the proposed adaptive virtual inertia uses a linear quadratic regulator to ensure the optimal balance between fast frequency response and wind turbine generator system stress during disturbances. Hence, it minimizes frequency deviations with minimum effort. Several case simulations are proposed and carried out in MATLAB/Simulink software, and the results demonstrate the effectiveness and feasibility of the proposed adaptive virtual inertia synchronverter based on a linear quadratic regulator. The maximum and minimum frequency, the rate change of the frequency, and the integral of time-weighted absolute error are computed to quantify the performance of the proposed adaptive virtual inertia. These indexes are reduced by 46.61%, 52.67%, 79.41%, and 34.66%, in the worst case, when the proposed adaptive model is compared to the conventional synchronverter model.

ACS Style

Walter Gil-González; Oscar Montoya; Andrés Escobar-Mejía; Jesús Hernández. LQR-Based Adaptive Virtual Inertia for Grid Integration of Wind Energy Conversion System Based on Synchronverter Model. Electronics 2021, 10, 1022 .

AMA Style

Walter Gil-González, Oscar Montoya, Andrés Escobar-Mejía, Jesús Hernández. LQR-Based Adaptive Virtual Inertia for Grid Integration of Wind Energy Conversion System Based on Synchronverter Model. Electronics. 2021; 10 (9):1022.

Chicago/Turabian Style

Walter Gil-González; Oscar Montoya; Andrés Escobar-Mejía; Jesús Hernández. 2021. "LQR-Based Adaptive Virtual Inertia for Grid Integration of Wind Energy Conversion System Based on Synchronverter Model." Electronics 10, no. 9: 1022.

Journal article
Published: 08 April 2021 in Applied Sciences
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This paper proposes a new hybrid master–slave optimization approach to address the problem of the optimal placement and sizing of distribution static compensators (D-STATCOMs) in electrical distribution grids. The optimal location of the D-STATCOMs is identified by implementing the classical and well-known Chu and Beasley genetic algorithm, which employs an integer codification to select the nodes where these will be installed. To determine the optimal sizes of the D-STATCOMs, a second-order cone programming reformulation of the optimal power flow problem is employed with the aim of minimizing the total costs of the daily energy losses. The objective function considered in this study is the minimization of the annual operative costs associated with energy losses and installation investments in D-STATCOMs. This objective function is subject to classical power balance constraints and device capabilities, which generates a mixed-integer nonlinear programming model that is solved with the proposed genetic-convex strategy. Numerical validations in the 33-node test feeder with radial configuration show the proposed genetic-convex model’s effectiveness to minimize the annual operative costs of the grid when compared with the optimization solvers available in GAMS software.

ACS Style

Oscar Montoya; Harold Chamorro; Lazaro Alvarado-Barrios; Walter Gil-González; César Orozco-Henao. Genetic-Convex Model for Dynamic Reactive Power Compensation in Distribution Networks Using D-STATCOMs. Applied Sciences 2021, 11, 3353 .

AMA Style

Oscar Montoya, Harold Chamorro, Lazaro Alvarado-Barrios, Walter Gil-González, César Orozco-Henao. Genetic-Convex Model for Dynamic Reactive Power Compensation in Distribution Networks Using D-STATCOMs. Applied Sciences. 2021; 11 (8):3353.

Chicago/Turabian Style

Oscar Montoya; Harold Chamorro; Lazaro Alvarado-Barrios; Walter Gil-González; César Orozco-Henao. 2021. "Genetic-Convex Model for Dynamic Reactive Power Compensation in Distribution Networks Using D-STATCOMs." Applied Sciences 11, no. 8: 3353.

Journal article
Published: 07 April 2021 in Electric Power Systems Research
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A fault in a power system generates economic losses, security problems, social problems and can even take human lives. Therefore, it is necessary to have an efficient fault location strategy to reduce the exposure time and recurrence of the fault. This paper presents an impedance-based method to estimate the fault location in transmission lines. The mathematical formulation considers the distributed parameters transmission line model for the estimation of the fault distance, and it is obtained by the application of Gauss-Newton method. Said method considers available voltage and current measurements at both terminals of the transmission line as well as the line parameters. Moreover, the method can be used for locating high and low impedance faults. Additionally, it is proposed an adjustable HIF model to validate its performance, which allows to generate synthetic high impedance faults by setting specific features of a HIF from simple input parameters. The error in fault location accuracy is under 0.1% for more than 90% of the performance test cases. The easy implementation of this method and encouraging test results indicate its potential for real-life applications.

ACS Style

Jose Doria-García; Cesar Orozco-Henao; Roberto Leborgne; Oscar Danilo Montoya; Walter Gil-González. High impedance fault modeling and location for transmission line✰. Electric Power Systems Research 2021, 196, 107202 .

AMA Style

Jose Doria-García, Cesar Orozco-Henao, Roberto Leborgne, Oscar Danilo Montoya, Walter Gil-González. High impedance fault modeling and location for transmission line✰. Electric Power Systems Research. 2021; 196 ():107202.

Chicago/Turabian Style

Jose Doria-García; Cesar Orozco-Henao; Roberto Leborgne; Oscar Danilo Montoya; Walter Gil-González. 2021. "High impedance fault modeling and location for transmission line✰." Electric Power Systems Research 196, no. : 107202.

Journal article
Published: 22 March 2021 in Electric Power Systems Research
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Distributed energy resources consideration by fault location formulations is a technical challenge. Stochastic behavior complicates deterministic solutions, while probabilistic approaches are yet to be fully explored. This paper presents analytical physics-based models towards the solution to this challenge. Presented models consider information availability from distributed energy resources to improve the fault location reliability. Information considered is divided into two categories: synchronized measurements provided by intelligent electronic devices located in the substation and in each terminal of distributed energy resources; and linear analytical-based models of distributed energy resources. Distributed energy resources models are used only when remote measurements are not available. Different distributed energy resources technologies and their operation modes are modeled. The presented fault location solution is validated on the IEEE 34-nodes test feeder modified. Easy-to-implement model, without hard-to-design parameters, built on the classical impedance-based fault location solution, indicates potential for real-life applications.

ACS Style

A.S. Bretas; C. Orozco-Henao; J. Marín-Quintero; O.D. Montoya; W. Gil-González; N.G. Bretas. Microgrids physics model-based fault location formulation: Analytic-based distributed energy resources effect compensation. Electric Power Systems Research 2021, 195, 107178 .

AMA Style

A.S. Bretas, C. Orozco-Henao, J. Marín-Quintero, O.D. Montoya, W. Gil-González, N.G. Bretas. Microgrids physics model-based fault location formulation: Analytic-based distributed energy resources effect compensation. Electric Power Systems Research. 2021; 195 ():107178.

Chicago/Turabian Style

A.S. Bretas; C. Orozco-Henao; J. Marín-Quintero; O.D. Montoya; W. Gil-González; N.G. Bretas. 2021. "Microgrids physics model-based fault location formulation: Analytic-based distributed energy resources effect compensation." Electric Power Systems Research 195, no. : 107178.

Journal article
Published: 02 March 2021 in Applied Sciences
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The problem of reactive power compensation in electric distribution networks is addressed in this research paper from the point of view of the combinatorial optimization using a new discrete-continuous version of the vortex search algorithm (DCVSA). To explore and exploit the solution space, a discrete-continuous codification of the solution vector is proposed, where the discrete part determines the nodes where the distribution static compensator (D-STATCOM) will be installed, and the continuous part of the codification determines the optimal sizes of the D-STATCOMs. The main advantage of such codification is that the mixed-integer nonlinear programming model (MINLP) that represents the problem of optimal placement and sizing of the D-STATCOMs in distribution networks only requires a classical power flow method to evaluate the objective function, which implies that it can be implemented in any programming language. The objective function is the total costs of the grid power losses and the annualized investment costs in D-STATCOMs. In addition, to include the impact of the daily load variations, the active and reactive power demand curves are included in the optimization model. Numerical results in two radial test feeders with 33 and 69 buses demonstrate that the proposed DCVSA can solve the MINLP model with best results when compared with the MINLP solvers available in the GAMS software. All the simulations are implemented in MATLAB software using its programming environment.

ACS Style

Oscar Montoya; Walter Gil-González; Jesus Hernández. Efficient Operative Cost Reduction in Distribution Grids Considering the Optimal Placement and Sizing of D-STATCOMs Using a Discrete-Continuous VSA. Applied Sciences 2021, 11, 2175 .

AMA Style

Oscar Montoya, Walter Gil-González, Jesus Hernández. Efficient Operative Cost Reduction in Distribution Grids Considering the Optimal Placement and Sizing of D-STATCOMs Using a Discrete-Continuous VSA. Applied Sciences. 2021; 11 (5):2175.

Chicago/Turabian Style

Oscar Montoya; Walter Gil-González; Jesus Hernández. 2021. "Efficient Operative Cost Reduction in Distribution Grids Considering the Optimal Placement and Sizing of D-STATCOMs Using a Discrete-Continuous VSA." Applied Sciences 11, no. 5: 2175.

Journal article
Published: 24 February 2021 in Applied Sciences
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Phase balancing is a classical optimization problem in power distribution grids that involve phase swapping of the loads and generators to reduce power loss. The problem is a non-linear integer and, hence, it is usually solved using heuristic algorithms. This paper proposes a mathematical reformulation that transforms the phase-balancing problem in low-voltage distribution networks into a mixed-integer convex quadratic optimization model. To consider both conventional secondary feeders and microgrids, renewable energies and their subsequent stochastic nature are included in the model. The power flow equations are linearized, and the combinatorial part is represented using a Birkhoff polytope B 3 that allows the selection of phase swapping in each node. The numerical experiments on the CIGRE low-voltage test system demonstrate the use of the proposed formulation.

ACS Style

Alejandro Garces; Walter Gil-González; Oscar Montoya; Harold Chamorro; Lazaro Alvarado-Barrios. A Mixed-Integer Quadratic Formulation of the Phase-Balancing Problem in Residential Microgrids. Applied Sciences 2021, 11, 1972 .

AMA Style

Alejandro Garces, Walter Gil-González, Oscar Montoya, Harold Chamorro, Lazaro Alvarado-Barrios. A Mixed-Integer Quadratic Formulation of the Phase-Balancing Problem in Residential Microgrids. Applied Sciences. 2021; 11 (5):1972.

Chicago/Turabian Style

Alejandro Garces; Walter Gil-González; Oscar Montoya; Harold Chamorro; Lazaro Alvarado-Barrios. 2021. "A Mixed-Integer Quadratic Formulation of the Phase-Balancing Problem in Residential Microgrids." Applied Sciences 11, no. 5: 1972.

Journal article
Published: 15 February 2021 in Electric Power Systems Research
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This paper addresses the problem of optimal conductor selection in direct current (DC) distribution networks with radial topology. A nonlinear mixed-integer programming model (MINLP) is developed through a branch-to-node incidence matrix. An important contribution is that the proposed MINLP model integrates a set of constraints related to the telescopic structure of the network, which allows reducing installation costs. The proposed model also includes a time-domain dependency that helps analyze the DC network under different load conditions, including renewable generation and battery energy storage systems, and different voltage regulation operative consigns. The objective function of the proposed model is made up of the total investment in conductors and the total cost of energy losses in one year of operation. These components of the objective function show multi-objective behavior. For this reason, different simulation scenarios are performed to identify their effects on the final grid configuration. An illustrative 10-nodes medium-voltage DC grid with 9 lines is used to carry out all the simulations through the General Algebraic Modeling System known as GAMS.

ACS Style

Oscar Danilo Montoya; Walter Gil-González; Luis F. Grisales-Noreña. On the mathematical modeling for optimal selecting of calibers of conductors in DC radial distribution networks: An MINLP approach. Electric Power Systems Research 2021, 194, 107072 .

AMA Style

Oscar Danilo Montoya, Walter Gil-González, Luis F. Grisales-Noreña. On the mathematical modeling for optimal selecting of calibers of conductors in DC radial distribution networks: An MINLP approach. Electric Power Systems Research. 2021; 194 ():107072.

Chicago/Turabian Style

Oscar Danilo Montoya; Walter Gil-González; Luis F. Grisales-Noreña. 2021. "On the mathematical modeling for optimal selecting of calibers of conductors in DC radial distribution networks: An MINLP approach." Electric Power Systems Research 194, no. : 107072.

Journal article
Published: 11 January 2021 in Applied Sciences
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The optimal placement and sizing of distributed generators is a classical problem in power distribution networks that is usually solved using heuristic algorithms due to its high complexity. This paper proposes a different approach based on a mixed-integer second-order cone programming (MI-SOCP) model that ensures the global optimum of the relaxed optimization model. Second-order cone programming (SOCP) has demonstrated to be an efficient alternative to cope with the non-convexity of the power flow equations in power distribution networks. Of relatively new interest to the power systems community is the extension to MI-SOCP models. The proposed model is an approximation. However, numerical validations in the IEEE 33-bus and IEEE 69-bus test systems for unity and variable power factor confirm that the proposed MI-SOCP finds the best solutions reported in the literature. Being an exact technique, the proposed model allows minimum processing times and zero standard deviation, i.e., the same optimum is guaranteed at each time that the MI-SOCP model is solved (a significant advantage in comparison to metaheuristics). Additionally, load and photovoltaic generation curves for the IEEE 69-node test system are included to demonstrate the applicability of the proposed MI-SOCP to solve the problem of the optimal location and sizing of renewable generators using the multi-period optimal power flow formulation. Therefore, the proposed MI-SOCP also guarantees the global optimum finding, in contrast to local solutions achieved with mixed-integer nonlinear programming solvers available in the GAMS optimization software. All the simulations were carried out via MATLAB software with the CVX package and Gurobi solver.

ACS Style

Walter Gil-González; Alejandro Garces; Oscar Danilo Montoya; Jesus C. Hernández. A Mixed-Integer Convex Model for the Optimal Placement and Sizing of Distributed Generators in Power Distribution Networks. Applied Sciences 2021, 11, 627 .

AMA Style

Walter Gil-González, Alejandro Garces, Oscar Danilo Montoya, Jesus C. Hernández. A Mixed-Integer Convex Model for the Optimal Placement and Sizing of Distributed Generators in Power Distribution Networks. Applied Sciences. 2021; 11 (2):627.

Chicago/Turabian Style

Walter Gil-González; Alejandro Garces; Oscar Danilo Montoya; Jesus C. Hernández. 2021. "A Mixed-Integer Convex Model for the Optimal Placement and Sizing of Distributed Generators in Power Distribution Networks." Applied Sciences 11, no. 2: 627.

Journal article
Published: 09 December 2020 in Electronics
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This paper explores a methodology to locate battery energy storage systems (BESS) in rural alternating current (AC) distribution networks fed by diesel generators to minimize total greenhouse gas emissions. A mixed-integer nonlinear programming (MINLP) model is formulated to represent the problem of greenhouse gas emissions minimization, considering power balance and devices capabilities as constraints. To model the BESS systems, a linear relationship is considered between the state of charge and the power injection/consumption using a charging/discharging coefficient. The solution of the MINLP model is reached through the general algebraic modeling system by employing the BONMIN solver. Numerical results in a medium-voltage AC distribution network composed of 33 nodes and 32 branches operated with 12.66 kV demonstrate the effectiveness of including BESS systems to minimize greenhouse gas emissions in diesel generators that feeds rural distribution networks.

ACS Style

Oscar Danilo Montoya; Walter Gil-González; Jesus C. Hernández. Optimal Selection and Location of BESS Systems in Medium-Voltage Rural Distribution Networks for Minimizing Greenhouse Gas Emissions. Electronics 2020, 9, 2097 .

AMA Style

Oscar Danilo Montoya, Walter Gil-González, Jesus C. Hernández. Optimal Selection and Location of BESS Systems in Medium-Voltage Rural Distribution Networks for Minimizing Greenhouse Gas Emissions. Electronics. 2020; 9 (12):2097.

Chicago/Turabian Style

Oscar Danilo Montoya; Walter Gil-González; Jesus C. Hernández. 2020. "Optimal Selection and Location of BESS Systems in Medium-Voltage Rural Distribution Networks for Minimizing Greenhouse Gas Emissions." Electronics 9, no. 12: 2097.

Journal article
Published: 03 December 2020 in Electronics
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This study analyzes the numerical convergence and processing time required by several classical and new solution methods proposed in the literature to solve the power-flow problem (PF) in direct-current (DC) networks considering radial and mesh topologies. Three classical numerical methods were studied: Gauss–Jacobi, Gauss–Seidel, and Newton–Raphson. In addition, two unconventional methods were selected. They are iterative and allow solving the DC PF in radial and mesh configurations. The first method uses a Taylor series expansion and a set of decoupling equations to linearize around the desired operating point. The second method manipulates the set of non-linear equations of the DC PF to transform it into a conventional fixed-point form. Moreover, this method is used to develop a successive approximation methodology. For the particular case of radial topology, three methods based on triangular matrix formulation, graph theory, and scanning algorithms were analyzed. The main objective of this study was to identify the methods with the best performance in terms of quality of solution (i.e., numerical convergence) and processing time to solve the DC power flow in mesh and radial distribution networks. We aimed at offering to the reader a set of PF methodologies to analyze electrical DC grids. The PF performance of the analyzed solution methods was evaluated through six test feeders; all of them were employed in prior studies for the same application. The simulation results show the adequate performance of the power-flow methods reviewed in this study, and they permit the selection of the best solution method for radial and mesh structures.

ACS Style

Luis Fernando Grisales-Noreña; Oscar Danilo Montoya; Walter Julian Gil-González; Alberto-Jesus Perea-Moreno; Miguel-Angel Perea-Moreno. A Comparative Study on Power Flow Methods for Direct-Current Networks Considering Processing Time and Numerical Convergence Errors. Electronics 2020, 9, 2062 .

AMA Style

Luis Fernando Grisales-Noreña, Oscar Danilo Montoya, Walter Julian Gil-González, Alberto-Jesus Perea-Moreno, Miguel-Angel Perea-Moreno. A Comparative Study on Power Flow Methods for Direct-Current Networks Considering Processing Time and Numerical Convergence Errors. Electronics. 2020; 9 (12):2062.

Chicago/Turabian Style

Luis Fernando Grisales-Noreña; Oscar Danilo Montoya; Walter Julian Gil-González; Alberto-Jesus Perea-Moreno; Miguel-Angel Perea-Moreno. 2020. "A Comparative Study on Power Flow Methods for Direct-Current Networks Considering Processing Time and Numerical Convergence Errors." Electronics 9, no. 12: 2062.

Journal article
Published: 02 December 2020 in Applied Sciences
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This research addresses the problem of the optimal location and sizing distributed generators (DGs) in direct current (DC) distribution networks from the combinatorial optimization. It is proposed a master–slave optimization approach in order to solve the problems of placement and location of DGs, respectively. The master stage applies to the classical Chu & Beasley genetic algorithm (GA), while the slave stage resolves a second-order cone programming reformulation of the optimal power flow problem for DC grids. This master–slave approach generates a hybrid optimization approach, named GA-SOCP. The main advantage of optimal dimensioning of DGs via SOCP is that this method makes part of the exact mathematical optimization that guarantees the possibility of finding the global optimal solution due to the solution space’s convex structure, which is a clear improvement regarding classical metaheuristic optimization methodologies. Numerical comparisons with hybrid and exact optimization approaches reported in the literature demonstrate the proposed hybrid GA-SOCP approach’s effectiveness and robustness to achieve the global optimal solution. Two test feeders compose of 21 and 69 nodes that can locate three distributed generators are considered. All of the computational validations have been carried out in the MATLAB software and the CVX tool for convex optimization.

ACS Style

Oscar Danilo Montoya; Walter Gil-González; Luis Fernando Grisales-Noreña. Hybrid GA-SOCP Approach for Placement and Sizing of Distributed Generators in DC Networks. Applied Sciences 2020, 10, 8616 .

AMA Style

Oscar Danilo Montoya, Walter Gil-González, Luis Fernando Grisales-Noreña. Hybrid GA-SOCP Approach for Placement and Sizing of Distributed Generators in DC Networks. Applied Sciences. 2020; 10 (23):8616.

Chicago/Turabian Style

Oscar Danilo Montoya; Walter Gil-González; Luis Fernando Grisales-Noreña. 2020. "Hybrid GA-SOCP Approach for Placement and Sizing of Distributed Generators in DC Networks." Applied Sciences 10, no. 23: 8616.

Journal article
Published: 02 November 2020 in Energies
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This paper addresses the voltage stability margin calculation in medium-voltage distribution networks in the context of exact mathematical modeling. This margin calculation is performed with a second-order cone (SOCP) reformulation of the classical nonlinear non-convex optimal power flow problems. The main idea around the SOCP approximation is to guarantee the global optimal solution via convex optimization, considering as the objective function the λ-coefficient associated with the maximum possible increment of the load consumption at all the nodes. Different simulation cases are considered in one test feeder, described as follows: (i) the distribution network without penetration of distributed generation; (ii) the distribution network with penetration of distributed generation; and (iii) the distribution grid with capacitive compensation. Numerical results in the test system demonstrated the effectiveness of the proposed SOCP approximation to determine the λ-coefficient. In addition, the proposed approximation is compared with nonlinear tools available in the literature. All the simulations are carried out in the MATLAB software with the CVX package and the Gurobi solver.

ACS Style

Oscar Danilo Montoya; Walter Gil-González; Andrés Arias-Londoño; Arul Rajagopalan; Jesus C. Hernández. Voltage Stability Analysis in Medium-Voltage Distribution Networks Using a Second-Order Cone Approximation. Energies 2020, 13, 5717 .

AMA Style

Oscar Danilo Montoya, Walter Gil-González, Andrés Arias-Londoño, Arul Rajagopalan, Jesus C. Hernández. Voltage Stability Analysis in Medium-Voltage Distribution Networks Using a Second-Order Cone Approximation. Energies. 2020; 13 (21):5717.

Chicago/Turabian Style

Oscar Danilo Montoya; Walter Gil-González; Andrés Arias-Londoño; Arul Rajagopalan; Jesus C. Hernández. 2020. "Voltage Stability Analysis in Medium-Voltage Distribution Networks Using a Second-Order Cone Approximation." Energies 13, no. 21: 5717.

Journal article
Published: 30 October 2020 in Applied Sciences
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This paper deals with a classical problem in power system analysis regarding the optimal location and sizing of distributed generators (DGs) in direct current (DC) distribution networks using the mathematical optimization. This optimization problem is divided into two sub-problems as follows: the optimal location of DGs is a problem, with those with a binary structure being the first sub-problem; and the optimal sizing of DGs with a nonlinear programming (NLP) structure is the second sub-problem. These problems originate from a general mixed-integer nonlinear programming model (MINLP), which corresponds to an NP-hard optimization problem. It is not possible to provide the global optimum with conventional programming methods. A mixed-integer semidefinite programming (MI-SDP) model is proposed to address this problem, where the binary part is solved via the branch and bound (B&B) methods and the NLP part is solved via convex optimization (i.e., SDP). The main advantage of the proposed MI-SDP model is the possibility of guaranteeing a global optimum solution if each of the nodes in the B&B search is convex, as is ensured by the SDP method. Numerical validations in two test feeders composed of 21 and 69 nodes demonstrate that in all of these problems, the optimal global solution is reached by the MI-SDP approach, compared to the classical metaheuristic and hybrid programming models reported in the literature. All the simulations have been carried out using the MATLAB software with the CVX tool and the Mosek solver.

ACS Style

Walter Gil-González; Alexander Molina-Cabrera; Oscar Danilo Montoya; Luis Fernando Grisales-Noreña. An MI-SDP Model for Optimal Location and Sizing of Distributed Generators in DC Grids That Guarantees the Global Optimum. Applied Sciences 2020, 10, 7681 .

AMA Style

Walter Gil-González, Alexander Molina-Cabrera, Oscar Danilo Montoya, Luis Fernando Grisales-Noreña. An MI-SDP Model for Optimal Location and Sizing of Distributed Generators in DC Grids That Guarantees the Global Optimum. Applied Sciences. 2020; 10 (21):7681.

Chicago/Turabian Style

Walter Gil-González; Alexander Molina-Cabrera; Oscar Danilo Montoya; Luis Fernando Grisales-Noreña. 2020. "An MI-SDP Model for Optimal Location and Sizing of Distributed Generators in DC Grids That Guarantees the Global Optimum." Applied Sciences 10, no. 21: 7681.

Journal article
Published: 26 October 2020 in Applied Soft Computing
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Conventional protection schemes have proven insufficient for the protection of Active Distribution Networks (ADN). Novel protection schemes with an adaptive approach should be developed to guarantee the protection of ADN under all their operating conditions. This paper proposes an ADN adaptive protection methodology, which is based on an intelligent approach fault detector over locally available measurements. This approach uses Machine Learning (ML) based techniques to reduce the strong dependence of the adaptive protection schemes on the availability of communication systems and to determine if, over a fault condition, an Intelligent Electronic Device (IED) should operate considering the changes in operational conditions of an ADN. Additionally, the methodology takes into account different and remarkable recommendations for the use of ML techniques. The proposed methodology is validated on the modified IEEE 34-nodes test feeder. Additionally, it takes into consideration typical features of ADN and micro-grids like the load imbalance, reconfiguration, changes in impedance upstream from the micro-grid, and off-grid/on-grid operation modes. The results demonstrate the flexibility and simplicity of the methodology to determine the best accuracy performance among several ML models. Besides, they show the methodology’s versatility to find the suitable ML model for IEDs located on different zones of an ADN. The ease of design’s implementation, formulation of parameters, and promising test results indicate the potential for real-life applications.

ACS Style

J. Marín-Quintero; C. Orozco-Henao; W.S. Percybrooks; Juan C. Vélez; Oscar Danilo Montoya; W. Gil-González. Toward an adaptive protection scheme in active distribution networks: Intelligent approach fault detector. Applied Soft Computing 2020, 98, 106839 .

AMA Style

J. Marín-Quintero, C. Orozco-Henao, W.S. Percybrooks, Juan C. Vélez, Oscar Danilo Montoya, W. Gil-González. Toward an adaptive protection scheme in active distribution networks: Intelligent approach fault detector. Applied Soft Computing. 2020; 98 ():106839.

Chicago/Turabian Style

J. Marín-Quintero; C. Orozco-Henao; W.S. Percybrooks; Juan C. Vélez; Oscar Danilo Montoya; W. Gil-González. 2020. "Toward an adaptive protection scheme in active distribution networks: Intelligent approach fault detector." Applied Soft Computing 98, no. : 106839.

Journal article
Published: 26 October 2020 in Symmetry
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This paper deals with the global stabilization of the reaction wheel pendulum (RWP) in the discrete-time domain. The discrete-inverse optimal control approach via a control Lyapunov function (CLF) is employed to make the stabilization task. The main advantages of using this control methodology can be summarized as follows: (i) it guarantees exponential stability in closed-loop operation, and (ii) the inverse control law is optimal since it minimizes the cost functional of the system. Numerical simulations demonstrate that the RWP is stabilized with the discrete-inverse optimal control approach via a CLF with different settling times as a function of the control gains. Furthermore, parametric uncertainties and comparisons with nonlinear controllers such as passivity-based and Lyapunov-based approaches developed in the continuous-time domain have demonstrated the superiority of the proposed discrete control approach. All of these simulations have been implemented in the MATLAB software.

ACS Style

Oscar Danilo Montoya; Walter Gil-González; Juan A. Dominguez-Jimenez; Alexander Molina-Cabrera; Diego A. Giral-Ramírez. Global Stabilization of a Reaction Wheel Pendulum: A Discrete-Inverse Optimal Formulation Approach via A Control Lyapunov Function. Symmetry 2020, 12, 1771 .

AMA Style

Oscar Danilo Montoya, Walter Gil-González, Juan A. Dominguez-Jimenez, Alexander Molina-Cabrera, Diego A. Giral-Ramírez. Global Stabilization of a Reaction Wheel Pendulum: A Discrete-Inverse Optimal Formulation Approach via A Control Lyapunov Function. Symmetry. 2020; 12 (11):1771.

Chicago/Turabian Style

Oscar Danilo Montoya; Walter Gil-González; Juan A. Dominguez-Jimenez; Alexander Molina-Cabrera; Diego A. Giral-Ramírez. 2020. "Global Stabilization of a Reaction Wheel Pendulum: A Discrete-Inverse Optimal Formulation Approach via A Control Lyapunov Function." Symmetry 12, no. 11: 1771.