Idi Amin Isaac

Geomorphological stratification of the territory is rarely integrated explicitly into sizing models for hybrid solar–wind energy matrices, even though relief modulates both resources in opposite ways. This work proposes a four-stage model that combines geomorphological stratification by elevation ranges, resource-specific solar and wind characterization, a decision-tree surrogate model that reproduces the coupled physical simulation (PVWatts and PyWake) with high fidelity (R² > 0.99), and optimization through mixed-integer linear programming (MILP). MILP is subject to a hybridization constraint that prevents a single technology from occupying more than 80% of the installed area. The model was applied to a first location with four altitudinal strata and contrasted with a second one. For the first site, the wind resource was non-viable across all strata, and the model consistently selected exclusively solar configurations. At the second location, it selected a hybrid configuration with 73% wind and 27% solar energy, whose proportions are governed by the hybridization threshold. Uncertainty and sensitivity analyses showed that the technology selected is robust to the choice of representative point and to the out-of-sample behavior of the surrogate, whereas the wind non-viability of the first site depends on the reference height and shear assumptions of the reanalysis data.

Geomorphological stratification of the territory is rarely integrated explicitly into sizing models for hybrid solar-wind energy matrices, even though relief modulates both resources in opposite ways. This work proposes a four-stage model that combines geomorphological stratification by elevation ranges, resource-specific solar and wind characterization, a decision-tree surrogate model that reproduces the coupled physical simulation (PVWatts and the Jensen wake model) with high fidelity (R² > 0.99), and optimization through mixed-integer linear programming (MILP). MILP is subject to a hybridization constraint that prevents a single technology from occupying more than 80% of the installed area. The model was applied to a first geographical location, including four altitudinal strata, and subsequently contrasted with a second one. For the first site, the wind resource was non-viable across all strata, and the model consistently selected exclusively solar configurations. At the second location, in contrast, it autonomously proposed the construction of a real hybrid matrix with a 73% wind and 27% solar contribution. The same procedure, without external reparameterization between territories, adapted the technological composition to the local resource of each territory, which constitutes the main evidence of the ability of the model to be generalized across territories with diverse resource conditions.

Floating photovoltaic (FPV) systems are expected to outperform ground-mounted photovoltaic (GPV) systems due to water-based cooling; however, this advantage has been documented mainly for open float structures in temperate climates. Whether this cooling advantage extends to closed-platform FPV systems in tropical reservoirs, where water temperature can exceed ambient air temperature, remains unresolved. This study addresses that question using a reference GPV system at the same site with identical hardware, isolating platform type as the determining variable. A closed-platform floating FPV system and a GPV system were compared in a hydroelectric reservoir in Colombia over 12 months with hourly resolution. The GPV system generated 1,407 kWh/kWp per year, compared with 1,382 kWh/kWp for the FPV system, a difference of 25 kWh/kWp (1.75%). The FPV modules operated at higher temperatures during 70.5% of the monitored hours, with an average differential of +1.17 °C. The water beneath the platform reached a mean temperature of 30.98 °C, exceeding ambient temperature throughout the entire operating period. The closed platform blocked convective cooling, the trapped water retained heat, and the irregular bathymetry (6–38 m depth) restricted renewal of the surface layer. These results show that closed-platform FPV systems over warm tropical water bodies can act as net sources of heat. The water temperature profile and bathymetric characterization should be integrated into the prefeasibility phase of any FPV project considering closed flotation.

Anaerobic digestion is a sustainable approach for waste treatment and renewable biogas production. A key parameter for large-scale applications is the Biochemical Methane Potential (BMP), which enables methane yield estimation and facilitates process scale-up. This study introduces an automated, low-cost prototype for BMP testing, comprising three 2-L reactors with provisions for future expansion. Control and data acquisition are carried out by low-cost embedded systems integrated with sensors for pressure, temperature, pH, and biogas flow. The system was evaluated using a mixture of pig manure and sludge from a local wastewater treatment plant. Real-time monitoring of temperature, pH, and biogas production was achieved. The heat exchanger, designed through transient energy balance modeling, increased the reactor temperature from 20 °C (lab temp.) to 38 °C in 400 s. Overall, the prototype demonstrated reliable performance, achieving rapid heating, stable monitoring, and precise biogas flow quantification through both displacement and pressure methods.

The expansion of electric microgrids has led to the incorporation of new elements and technologies into the power grids, carrying power management challenges and the need of a well-designed control architecture to provide efficient and economic access to electricity. This paper presents the development of a flexible hourly day-ahead power dispatch architecture for distributed energy resources in microgrids, with cost-based or demand-based operation, built up in a multi-class Python environment with SQLExpress and InfluxDB databases storing the dispatcher and microgrid data, and its experimental implementation using Modbus communication. The experimental power dispatch architecture is described and each operation stage is detailed, including the considered mathematical models of the energy resources, the database management, the linear-programming optimization of power dispatch, and the Modbus setpoint writing. Validation studies of the proposed control system are presented for real-time digital-simulated devices and physical resources as a real application at the Universidad Pontificia Bolivariana (UPB) campus microgrid. The simulated and physical microgrid characteristics are described and the hourly dispatch results for generation, storage and load devices are presented, standing out as a reliable power management architecture for economic commitment and load peak shaving in simulated and real microgrids. The proposed architecture demonstrates its readiness for present and future electrical system challenges, effectively incorporating meteorological variations, renewable energy sources, and power demand fluctuations into the control framework, with a strong dependence on the quality of the meteorological forecast.

This paper addresses a proposal for the optimization and automation of the methodology of selectivity analysis in protection relays by fault sweeps, to improve selectivity and evaluate the operation times and coordination margins in a complex network composed by a large amount of overcurrent units. Through the operating times of the protection devices, it can be quickly identified the lack of coordination that may occur in the relays of the network for several topological conditions. The coordination times are obtained by a set of injected failures in the assets delimited by the scope of the selectivity study, and through an automatic systemic analysis it is sought to generate a diagnosis of the most critical points in which there is no correct selectivity within protection functions. The automation strategy of this work is designed and evaluated in DIgSILENT PowerFactory and Python computational tools. Through the scripting and automation module, a Python script is executed in the PowerFactory environment, and in this way the protection relays and the measurement transformers are modeled by assigning their respective settings and directionality. Finally, an analysis is carried out with criteria of the good setting of protection devices created by experts in the field, and a calculation file is generated with the optimized operating times of the protection devices and an analysis of selectivity between the overcurrent functions of the system.

Thermal power plants are the widely conventional generation unit technology used to produce electricity being controllable and dispatchable. The location of thermal power plants depends on the energy availability conditions of the areas and the capacity to fuels access. Their location and geographical distribution define a high level of concentration in areas defined as thermal districts and its location define reliability, security, availability, and flexibility indices to avoid critical scenario or support system from contingencies. However, in many cases the electrical configuration does not correspond to requirements. This paper links the concentration by political distribution in Colombia and the configuration used in the generating substations to guarantee requirements. The Hirschman-Herfindahl index as a market tool is used to evaluate energy concentration facing representative participation in certain departments of Colombia. Results evidenced configurations and concentration in a study case, results and analysis could be used for planner to promote participation, reliability and promote. The paper’s contribution and conclusions are linked to guide planners towards market and technical tool to evaluate installed capacities, avoid market concentration, and reduce risky scenarios.

Microgrids deal with challenges presented by intermittent distributed generation, electrical faults and mode transition. To address these issues, to understand their static and dynamic behavior, and to develop control systems, it is necessary to reproduce their stable operation and transient response through mathematical models. This paper presents a data-driven low-order model identification methodology applied to voltage characterization in a photovoltaic system of a real campus microgrid for secondary voltage regulation. First, a literature review is presented focusing on secondary voltage modeling strategies and control. Then, experimental data is used to estimate and validate a low-order MIMO (multiple input–multiple output) model of the microgrid, considering reactive power, solar irradiance, and power demand inputs and the voltage output of the grid node. The obtained model reproduced the real system response with an accuracy of 88.4%. This model is used for dynamical analysis of the microgrid and the development of a secondary voltage control system based on model predictive control (MPC). The MPC strategy uses polytopic invariant sets as terminal sets to guarantee stability. Simulations are carried out to evaluate the controller performance using experimental data from solar irradiance and power demand as the system disturbances. Successful regulation of the secondary voltage output is obtained with a fast response despite the wide range of disturbance values.

This paper presents a novel methodology for the calculation of angular indexes of an electrical system from stationary analysis, using load flow and nose curves (P–V) in each of the buses of the system to perform control actions and preserve or improve voltage stability. The control actions are proposed considering a novel method based on the concepts of the cutset angle (CA) and center of angle (COA). The target is a fast estimation of voltage-stability margins through an appropriate angular characterization of the whole system and for each load bus with a complete network and N-1 contingency criteria. The most significant enhancement is that the angular characterization is based on the COA, which is related to the angular dynamics of the system, and indirectly reflects the inertia and the respective angles of the generator rotor, as well as the impact on the angular equivalent-system model. Simulations showed that the COA is an important index to determine the location of occurrence of the events. The COA can also help aim where control actions, like the amount of load shedding, should be carried out to remedy the voltage problems. The proposed method is assessed and tested in the benchmark IEEE 39-bus system.