This study evaluates and compares centralized and distributed reactive power compensation strategies using Static Var Compensators (SVCs) to enhance the performance of a high-voltage transmission system in the Caribbean region of Colombia. The methodology comprises four stages: system characterization, assessment of the uncompensated condition under peak demand, definition of four SVC-based scenarios, and steady-state analysis through power flow simulations using DIgSILENT PowerFactory. SVCs were modeled as Thyristor-Controlled Devices (“SVC Type 1”) operating as PV nodes for voltage regulation. The evaluated scenarios include centralized SVCs at the Slack node, node N4, and node N20, as well as a distributed scheme across load nodes N51 to N55. Node selection was guided by power flow analysis, identifying voltage drops below 0.9 pu and overloads above 125%. Technically, the distributed strategy outperformed the centralized alternatives, reducing active power losses by 37.5%, reactive power exchange by 46.1%, and improving node voltages from 0.71 pu to values above 0.92 pu while requiring only 437 MVAr of compensation compared to 600 MVAr in centralized cases. Economically, the distributed configuration achieved the highest annual energy savings (36 GWh), the greatest financial return (USD 5.94 M/year), and the shortest payback period (7.4 years), highlighting its cost-effectiveness. This study’s novelty lies in its system-level comparison of SVC deployment strategies under real operating constraints. The results demonstrate that distributed compensation not only improves technical performance but also provides a financially viable solution for enhancing grid reliability in infrastructure-limited transmission systems.

This study explores advanced multivariate models that incorporate non-climatic exogenous variables for very short-term photovoltaic energy forecasting. By integrating historical energy data from multiple photovoltaic plants, the research aims to improve the prediction accuracy of a target plant while addressing critical challenges in electric power systems (EPS), such as frequency stability. Frequency stability becomes increasingly complex as renewable energy sources penetrate the grid because of their intermittent nature. To mitigate this challenge, precise forecasting of photovoltaic energy generation is essential for balancing supply and demand in real time. The performance of long short-term memory (LSTM) networks and bidirectional LSTM (BiLSTM) networks was compared over a 5 min horizon. Including energy generation data from neighboring plants significantly improved prediction accuracy compared to univariate models. Among the models, multivariate BiLSTM showed superior performance, achieving a lower root-mean-square error (RMSE) and higher correlation coefficients. Quantile regression applied to manage prediction uncertainty, providing robust confidence intervals. The results suggest that incorporating an exogenous power series effectively captures spatial correlations and enhances prediction accuracy. This approach offers practical benefits for optimizing grid management, reducing operational costs, improving the integration of renewable energy sources, and supporting frequency stability in power generation systems.

The Colombian government’s plan aims to strengthen the electricity sector through the implementation of Advanced Measurement Infrastructure, network automation, distributed resources, and electric vehicles. These initiatives present both technological and economic challenges, given the current conditions in various Colombian municipalities, many of which will struggle to meet them. In response to this need, it is proposed to evaluate a business model to encourage the development of projects that facilitate the modernization of the distribution network, by supporting the network operator as a strategic partner. The distribution network of the municipality of San José de Guaviare in Colombia is used as a case study. The results indicate that this approach is attractive for the public service provider and demonstrate that continuous improvement in service quality indicators can be achieved without significantly impacting the local population’s economy.

In a centralized wholesale power system market scenario, the transmission and distribution constraints limit dispatch and require additional generation to support an integrated area known as Security Generation. This one must be covered in each area, and its cost transferred to the final users. The security generation cost gets higher when operation implicates the use of thermal power plants whose price equation depends on international fuels costs. This paper examines the consequences of a high reliance on thermal power plants. It focuses on scheduled reserves affecting electricity unit costs and the potential for constraints to lead to long-term consequences. The paper analyzes the security generation behavior based on reports and uses a real scenario to support simulations and decisions, evidencing monthly cost and an estimated CO2 emission. Results show the direct cost-saving potential of investing in renewable projects and technology. The paper can allow to replicate the analysis in comparable areas and regions with similar challenges.

Electricity is essential for the economic and social development of communities. The national government in each territory regulates electricity because is a public service. Utilities manage the electricity supply to meet the communities’ demand while considering economic and financial feasibility. Regulation’s purpose is to ensure efficient, secure, and reliable operation within the sector, maintaining quality and safety. This paper contains an analysis of the management criteria for the quality of the electrical energy service and the indicators in the Caribbean region of Colombia.

This paper presents the application of quantitative and qualitative methods to assess reliability and security in urban electrical substations. The method is a visual technique based on a conceptual analysis of the different substation configurations. We also performed a sensitivity analysis considering the effects of connecting and disconnecting various elements of a power system. The procedure considers evaluating the loadability levels of transformers, buses, and lines, as well as the current state of the individual elements and the number of connected elements. A new index was proposed for urban electrical substations, evaluating the non-attended demand risk. The technique was tested in a power system case study with a meshed subtransmission network and distribution circuits to supply power to the loads. The results showed that the proposed method is a useful qualitative method to obtain a quantitative description of the system during operation in critical cases and the non-attended demand risk. In addition, 30% of the electrical substations showed low reliability indicators for critical cases such as failures in transformers that connect different internal configurations. These findings could be of interest for utilities and operators, as this document provides a simplified and graphic method that can integrate components such as configurations, non-attended demand risk, and loadability indicators as key parameters to identify critical points that affect the reliability and security of power systems. The case study showed that the electrical substations with the highest non-attention demand risk, around 50%, were those with single- and double-bar configurations in their respective switchyards. On the other hand, the substations with the lowest risk of unmet demand, equal to or less than 20%, were electrical substations with a double-bar + bypass switch configuration, a double-bar and ring configuration in the 110 kV switchyard, and a single-bar configuration in the 13.8 kV switchyard. This study showed that those substations that had couplings had a higher probability of withstanding contingencies.

This paper evaluates the operational energy performance of a system to produce domestic hot water using waste heat in a centralised air conditioning system in a hotel in Cuba.The hotel facility has two different chillers capacities, where the system recovers the condensed heat through a heat exchanger at the compression process outlet.These schemes allow the simultaneous production of air conditioning and Domestic Hot Water, also those considering thermal storage tanks.The system modelling starts analyzing its components and processes based on the traditional thermodynamics and heat transfer equations and ends with a validation process.This model estimates a wide range of operating conditions, such as the thermal demands of the cooling load, the chiller water temperature, the electricity consumed by chillers, and the climatological variables involved.The system is evaluated in the highest tourism season in Cuba during a year under partial load.Results were validated in a hotel as a study case, which allowed us to estimate the thermal potential available in the plant to meet the thermal demand of the hot water required and show that variations in the chiller operation affect the temperature stability in the hot water system.

This paper presents a methodology based on the ISO-50001 standard to assess the energy impact of replacing standard-efficiency motors with high-efficiency motors driven by variable speed drives in an industrial pumping system.The methodology includes the inspection and installation of the new technology, measurements, data processing, and analysis of the results.In addition, an energy efficiency indicator, an energy baseline, and a Pareto diagram are used, while the harmonics generated by new technologies are evaluated.The contribution of the methodology is that it allows for a comprehensive energy diagnosis using easily measurable data like electricity consumption and water flow, replacing the measurement of the motor's mechanical power in industrial conditions, which is a current challenge.The methodology applied in the case study showed that the technological changes saved 36% of energy and that the variable speed drives increased current harmonics by 10%.

As part of the design process of a chiller plant, one of the final stages is the energy testing of the system in relation to future operating conditions. Recent studies have suggested establishing robust solutions, but a conservative approach still prevails at this stage. However, the results of some recent studies suggest the application of a new co-design (control–design) approach. The present research involves a comparative analysis between the use of conventional staging and the co-design approach in the design phase of a chiller plant. This paper analyzes the energy consumption estimations of six different chiller plant combinations for a Cuban hotel. For the conservative approach using on/off traditional staging, the results suggest that the best option would be the adoption of a chiller plant featuring a symmetrical configuration. However, the outcomes related to the co-design approach suggest that the best option would be an asymmetrical configuration. The energy savings results were equal to 24.8% and the resulting coefficient of performance (COP) was 59.7% greater than that of the symmetrical configuration. This research lays firm foundations for the correct choice and design of a suitable chiller plant configuration for a selected hotel, allowing for significant energy savings in the tourism sector.

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.

This paper presents a procedure to determine the cooling capacity distribution of the chillers composing a chiller plant using a statistical analysis of the building cooling demand. The mathematical-statistical procedure uses tools such as frequency histograms, box-and-whisker plots, stem-and-leaf plots, the generalized least squares method, and finally an iterative factorial procedure to generate from the processed information. Besides the manufacturer's data, all possible chiller plant combinations considering design constraints. The procedure was verified in a hotel facility. Eight thermal demand profiles were simulated. Statistical analysis yielded a range of individual capacities between 100–353 kW. The procedure generated 189 refrigeration plant combinations between 2 to 5 chillers, with a safety factor (SF) between 10%–20%. The highest number of combinations considered plants comprising three and four chillers, reaching 50 and 70 chiller plant options, respectively.

An appropriate design of a chiller plant is crucial to guarantee highly performing solutions. However, several design variables, such as type of systems, total cooling capacity, and hydraulic arrangement, need to be considered. On the one hand, at present, different technical criteria for selecting the most suitable design variables are available. Studies that corroborate the influence of the design variables over the operational variables are missing. In order to fill this knowledge gap, this work proposes a statistical analysis of design variables in chiller plants operating in medium- and large-scale applications and evaluates their influence on energy consumption and life cycle cost (LCC) under the same thermal demand conditions. A case study involving 138 chiller plant combinations featuring different arrangements and a Cuban hotel was selected. The results suggested that the total chiller design and cooling capacity distribution among chillers have a significant influence on the energy consumption of the chiller plant with a Spearman’s Rho and Kendall Tau (τ) correlation index value of −0.625 and 0.559, respectively. However, with LCC, only the cooling capacity distribution among the chillers had a certain influence with a Kendall Tau correlation index value of 0.289. As for the considered total cooling capacity, the applied statistical test showed that this design variable does not have any influence on performing the chiller plant.

Single-phase distribution transformers are commonly installed in outdoor distribution networks to supply electricity to final users. Utilities are used to receive abnormal operating reports related to typical failures that negatively affect the reliability and security indicators. Therefore, a follow-up model is proposed in this paper to evaluate the failure factors of distribution transformers installed in high environmental pollution zones. The results show that the main factors that cause failures are overload, overvoltage, overcurrent, moisture, hot spots, manufacturing process, and lack of technical knowledge. Furthermore, all those factors are presented in a typical case using time-lines diagrams to characterize the main failures. Finally, hot spots, overloads, and unauthorized connections are the most critical failure factors identified in the research. According to the statistical analysis, those failures could occur 16 days after installing the transformer. The follow-up model presented in this research can characterize the main failures presented in outdoor distribution transformers.

The renewable energy sources (RESs) projects are solutions with environmental benefits that are changing the traditional power system operation and concept. Transient stability analysis has opened new research trends to guarantee a secure operation high penetration. Problems such as frequency fluctuations, decoupling between generator angular speed, network frequency fluctuation and kinetic energy storing absence are the main non-conventional RESs penetration in power systems. This paper analyzes short-circuit influence on frequency response, focusing on weak distribution networks and isolated, to demonstrate relevance in frequency stability. A study case considered a generation outage and a load input to analyze frequency response. The paper compares frequency response during a generation outage with a short-circuit occurrence. In addition, modular value and angle generator terminal voltage affectation by electric arc and network ratio R⁄X, failure type influence in power delivered behavior, considering fault location, arc resistance and load. The arc resistance is defined as an added resistance that appears during failure and influences voltage modulus and angle value results showing that intermittent non-conventional RES participation can lead to frequency fluctuations. Results showed that arc resistance, type of failure, location and loadability determine the influence of frequency response factors in weak power systems.

This work compares the thermal behavior of a distribution transformer when using as dielectric liquid a mineral oil or natural esters. These cases have been analyzed using Finite Elements Method (FEM) at the software COMSOL Multiphysics® with a 3D-symmetrical model through the Heat Transfer in Solid module. The results of simulations show a higher values of maximum temperature in mineral oil submerged transformer than in natural ester, for the same operational conditions.

This paper presents a mho distance relay simulation based on the phase comparison technique using a typical electrical power systems analysis software for two cases: when the operation state is close to the static voltage limit and during a dynamic perturbation in the system. The paper evaluates the impedance variations caused by complex voltage values, the mho polarization, and the comparator operating region into the complex plane. In addition, the paper found the information for the dynamic perturbations from the outputs considering a mid-term stability program. The simulation of the mho-phase comparator in the static voltage proximity limit detects unit distance elements with impedance measured close to reach the threshold in the steady-state. Dynamic mho simulations in the complex plane are successfully tested by plotting time phase difference curves on the comparator input signals. Relay programmers can use these curves to analyze other phase comparators applications and the corresponding models in the complex plane.

The article presents a novel methodology for designing chiller plants for a hotel facility to determine the optimal distribution of the chillers cooling capacity that compose the plant. The methodology proposes three phases. In the first, the statistical analysis allowed to determine the cooling demand required in the facility, where the constructed thermal demand profiles reflect future operating conditions, and to obtain the individual cooling capacities of the chillers. In the second phase, the black box models were built to simulate the chillers energy performance and, using a mathematical algorithm allows to obtain a combination of chiller plants. The third phase constitutes the energy evaluation through the solution of a mathematical optimization problem and using a genetic algorithm. This was carried out under the sequence approach and the optimal load of each machine against the working conditions. This analysis allows calculating the performance, the life cycle cost, and the indirect environmental impact. The paper proposes a case study to demonstrate the feasibility of applying the methodology to the initial design stage, achieving a saving of 14,4%. Finally, using statistical analysis, the method allows comparing the relationship between each chiller plant considering the design and operating parameters.

The electricity demand forecast allows countries to establish long-term plans and objectives for identifying gaps, selecting strategies, and designing the electric power system's architecture. Traditional models use GDP as the primary variable to forecast the electricity demand. The work presents an analysis of the relationship between electricity demand and economic growth, using regression methods with one or more variables. The GDP and sectoral GDP data was provided by Banco de la República de Colombia. The results validate the traditional model and offer alternative models that can relate the economy's different sectors with the electricity demand. Keywords: Energy Forecasting; Electricity Demand; Macroeconomics Indicator; Backward, Forward, and Stepwise methods. JEL Classifications: Q41, Q43, Q47. DOI: https://doi.org/10.32479/ijeep.11386

Received Mar 8, 2021 Revised Sep 9, 2021 Accepted Oct 2, 2021 Recent years have witnessed a dramatic growth in utilizing computational intelligence techniques for various domains. Coherently, malicious actors are expected to utilize these techniques against current security solutions. Despite the importance of these new potential threats, there remains a paucity of evidence on leveraging these research literature techniques. This article investigates the possibility of combining artificial neural networks and swarm intelligence to generate a new type of malware. We successfully created a proof of concept malware named X-ware, which we tested against the Windows-based systems. Developing this proof of concept may allow us to identify this potential threat’s characteristics for developing mitigation methods in the future. Furthermore, a method for recording the virus’s behavior and propagation throughout a file system is presented. The proposed virus prototype acts as a swarm system with a neural network-integrated for operations. The virus’s behavioral data is recorded and shown under a complex network format to describe the behavior and communication of the swarm. This paper has demonstrated that malware strengthened with computational intelligence is a credible threat. We envisage that our study can be utilized to assist current and future security researchers to help in implementing more effective countermeasures.

The tourism sector is one of the main worldwide economic sectors with sustained growth, demonstrating its strength and resilience. In this sector, energy uses have increased to ensure quality, guest comfort, and rate level requirements being a building with great energy consumption. Several factors influence and can produce a significant variation in hotel consumption even in facilities located in the same region; the difference in a four-star hotel can reach 114 kWh/m2/year. This paper deals with related aspects such as hotel design, operation, type of service, occupancy patterns, operating point and efficiency of a heating, ventilation, and air conditioning (HVAC) system where 30 to 50% of the energy is consumed. Also, previous works based on the implementation of non-conventional energy resources such as photovoltaics projects to replace fuel dependence and high costs in electricity bills were reviewed. where there are savings of up to 30% in electricity and 60% in gas consumption. However, the initial capital investment and payback period are high and require new features to be considered in these facilities.