Load Flow Research Articles

Modeling an Electrolyzer in a Graph-Based Framework

We propose a linear electrolyzer model for steady-state load flow analysis of multi-carrier energy networks, where the electrolyzer is capable of producing hydrogen gas and heat. For our electrolyzer model, we show that there are boundary conditions that lead to a well-posed problem. We derive these conditions for two cases, namely with a known and unknown heat efficiency parameter. Furthermore, the derived conditions are validated numerically. Moreover, we investigate the extensibility of our model by including nonlinear models from electricity, gas, and heat. In this setting, we derived boundary conditions based on our previous findings. Due to the involvement of nonlinearity, it is a challenge to prove that the boundary conditions lead to a well-posed problem. Therefore, we simulated the electrolyzer connected with an electricity, gas, and heat system. Additionally, we considered a known and unknown heat efficiency parameter. The numerical results support that the linear electrolyzer model is solvable in a multi-carrier energy network.

Combined effects of long-term cyclic loading and unidirectional flow induced scour on the mechanical responses of tetrapod jacket foundation supported offshore wind turbines

Combined effects of long-term cyclic loading and unidirectional flow induced scour on the mechanical responses of tetrapod jacket foundation supported offshore wind turbines

Enhancing the reliance of emergency power supply systems for nuclear facilities using hybrid system

The performance of an atomic facility depends on the efficient supply of electricity, particularly emergency loads like monitoring and control equipment, radiation safety systems, and emergency lights. Most nuclear facilities rely on diesel generators to supply emergency loads during grid outages. Due to the diesel generator's imperfections, such as its starting time, it may fail to deliver power because it is unavailable due to maintenance, failure to start, or failure to run and supply the load. It cannot immediately supply the critical loads, resulting in a blackout and the release of radioactive substances into the environment. To address the previous issues, this paper proposes an improved method to enhance the reliability of nuclear facilities for providing electricity to safety and critical consumers during normal and emergency operating modes. The approach incorporates a photovoltaic (PV) system/battery, and its robustness and performance are tested using load flow and transient stability analysis. The simulation results demonstrated the effectiveness and speed of the proposed method when compared to the traditional method, as the emergency consumers were successfully powered within a very short time without fluctuations, and the voltage reduction and frequency were within the nominal values. The electrical transient analyzer program (ETAP) is used to validate these results.

Volt/VAr Regulation of the West Mediterranean Regional Electrical Grids Using SVC/STATCOM Devices With Neural Network Algorithms

ABSTRACTReactive power compensation is now a challenging issue in maintaining adequate power quality and improving the performance of the transmission system. Many researchers have focused on the behavior of voltage in the unbalanced state, and the majority of the studies have been done with STATCOM. In this study, the increasing power demand in power grids and the challenges associated with maintaining power quality and stability are discussed. The power system in the western Mediterranean region of Turkey is modeled with the DigSILENT Power Factory program using real data. It highlights the importance of reactive power compensation and introduces FACTS devices as a solution to control power factors and reactive power in the grid. In the realistic model, voltage and reactive power regulation is achieved by using SVC and STATCOM devices to ensure voltage stability. A load flow and short circuit analysis is performed on the designed transmission system for a number of critical scenarios. The modeled power system is optimized for the size and location of the FACTS devices by applying genetic algorithms (GAs) and particle swarm optimization (PSO) algorithms to the selected busbars of the FACTS devices, a strategy designed to significantly reduce system losses. The load values used in the heuristics differ from those used in other studies in that they use a realistic load profile that varies randomly and instantaneously over the long term, as opposed to a fixed load profile. All the comparative results show that the STATCOM controller can maintain the most significant reduction in technical losses and excellent performance in controlling the reactive power response under various outages. The effectiveness of the proposed methodology has been validated in various outage scenarios, and it has been shown that it will reduce the total cost of electricity generation in the western Mediterranean region on an annual basis. Considering the results of the Turkish National Transmission System, increasing voltage sensitivity and reactive power control can be beneficial in reducing power transmission costs and maintaining the balance between generation and consumption.

Integration of Total Maximum Daily Load (TMDL) and Environmental Flow Assessment (EFA) Concepts as an Adaptive Approach to Pollutant Loading Management in Asia: A Review

Water scarcity and pollution are escalating challenges in Asia, impacting ecological systems and human livelihoods. This paper reviews the integration of Total Maximum Daily Load (TMDL) and Environmental Flow Assessment (EFA) in water management to address the dual issues of water quality and quantity. TMDL focuses on regulating the number of pollutants entering water bodies to meet quality standards, while EFA ensures that enough water is available to support aquatic ecosystems. Their independent application, however, often leads to gaps—TMDL can overlook ecological needs, while EFA may neglect pollution control. The integration of these two frameworks offers a more holistic solution, especially in water-stressed regions like Southeast Asia, where moderate water availability is exacerbated by urbanization, industrialization, and agricultural runoff. Case studies from Malaysia, Indonesia, and China reveal the limitations of applying TMDL and EFA separately and underscore the necessity of addressing both ecological flow requirements and pollution limits. This paper identifies key pollutants such as biochemical oxygen demand (BOD), chemical oxygen demand (COD), heavy metals, and total suspended solids (TSS), particularly in urban and semi-urban areas, and highlights the importance of tailoring strategies to the specific needs of different regions. By combining TMDL and EFA, policymakers can better manage pollutant loads, secure ecological health, and address Asia’s pressing water management issues. This review emphasizes the need for adaptable, integrated water management strategies that account for seasonal fluctuations, competing water demands, and regional water availability and pollution differences.

Load Flow and Short Circuit Analysis in Central Part of Nepal using ETAP

This research focuses on conducting load flow and short-circuit analysis on a segment of central part of Nepalese power system, specifically from New Butwal substation to Dhalkebar substation. The analysis was initially carried out on a standard IEEE 5-bus system to validate the approach and methodology, followed by its application to the selected section of Nepalese power grid. Primary objective of this research was to evaluate the system’s performance under various faulty conditions and identify potential vulnerabilities. Nepal’s power system has been struggling with significant challenges, such as frequent outages, aging infrastructure, and a rapidly increasing electricity demand. This research applied Electrical Transient Analyzer Program software to construct and simulate the system, perform load flow studies, and analyze short-circuit scenarios on both IEEE 5 bus system and a central section of the Nepalese grid, changing faulty locations. It aimed to assess the impact of faults on different buses, identify sensitive nodes, and recommend strategies to minimize disruptions and maintain grid stability. Key findings revealed that Parwanipur 2 bus exhibited high sensitivity to faults in terms of current, while Dhalkebar bus was vulnerable in terms of voltage. These results indicated that the vulnerable system components require upgradation, such as the installation of surge protection devices, addition and upgradation of transmission lines, substations, transformers, are essential to mitigate potential risks. Overall, this research contributes to ongoing efforts to strengthen Nepal’s power system by providing valuable insights that can enhance future infrastructure development and operational strategies, ultimately enhancing the grid’s resilience and performance.

Evaluation of Intelligent Auxiliary Information Presentation Mode for Collaborative Flight Formation

Collaborative flight formations represent a promising operational model, but the integration of multi-source information in manned interfaces often results in cognitive overload and reduced situation awareness. This study evaluates the effectiveness of intelligent auxiliary information presentation modes in enhancing personnel capabilities. Using a simulation-based collaborative flight formation system, four presentation modes with varying levels of information and dynamics were experimentally tested and evaluated across subjective dimensions (cognitive workload, situation awareness, and interface design) and objective dimensions (design task flow information load and operational task flow information load). The results indicate that Level 3 and Level 4 modes significantly reduced mental workload and improved practical operational ability compared to the original mode. Level 3 achieved the highest interface evaluation scores, while Level 4 demonstrated the lowest design task flow information load. Both modes significantly enhanced situation awareness. Altogether, Level 3 and Level 4 resulted in the most significant improvements in personnel capabilities. These findings provide valuable insights for optimizing interface design and improving situation awareness in collaborative flight formation tasks.

Enhanced PV Network Controller for Optimizing Performance of LFC Power Systems

Turkey has made national energy accessibility the top of its priorities. Less than 90% of the nation's 82 million citizens can access electricity today. Workers use solar power and wind energy to provide more electricity across the nation. Solar power wind power and power electronics help Turkey save money as it works to fix its energy issues. Load Frequency Control inveters help Turkey as a developing country reduce solar power costs through advanced power electronics technologies. IC-based electronics improvements let us make energy components work better at less cost compared to previous expensive hardware. LFC inverters help add renewable energy to existing grids according to latest research and can solve energy problems worldwide. The analysis sees solar power providing 35% of Turkey's power output by 2050. Wind energy stands out for its unmatched marginal fuel cost advantage. Utility-scale solar power beats other generation sources because it costs no fuel to produce power while releasing minimal greenhouse gases which supports global decarbonization efforts. The analysis shows that our updated energy model matches actual LFC metering data through similar energy output numbers and trends. Our predicted numbers using the standard Load Flow Control system proved less precise than actual measurements. Our simulation produced 3.9% additional renewable energy estimates than actual meter readings whereas the basic model showed 52% less output. Our revised energy model in MATLAB shows good precision when it uses 10% solar power and 9.90% wind power input. Our hybrid scheme produced precise predictions when combining both solar and wind systems with 57.16% solar and 57.20% wind percentages.

Improved grey wolf optimizer for optimal reactive power dispatch with integration of wind and solar energy

The aim of this paper is to present a new improved grey wolf optimizer (IGWO) to solve the optimal reactive power dispatch (ORPD) problem with and without penetration of renewable energy resources (RERs). It is a nonlinear multivariable problem of optimization, with multiconstraints. The purpose is to minimize real power losses and improve the voltage profile of a given electric system by adjusting control variables, such as generator voltages, tap ratios of a transformer, switching VAr sources, without violating technical constraints that are presented as equalities and inequalities. Methodology. Metaheuristics are stochastic algorithms that can be applied to solve a wide variety of optimization problems without needing specific problem structure information. The penetration of RERs into electric power networks has been increased considerably to reduce the dependence of conventional energy resources, reducing the generation cost and greenhouse emissions. It is essential to include these sources in power flow studies. The wind and photovoltaic based systems are the most applied technologies in electrical systems compared to other technologies of RERs. Moreover, grey wolf optimizer (GWO) is a powerful metaheuristic algorithm that can be used to solve optimization problems. It is inspired from the social hierarchy and hunting behavior of grey wolves in the wild. The novelty. This paper presents an IGWO to solve the ORPD problem in presence of RERs. Methods. The IGWO based on enhancing the exploitation phase of the conventional GWO. The robustness of the method is tested on the IEEE 30 bus test system. For the control variables, a mixed representation (continuous/discrete), is proposed. The obtained results demonstrate the effectiveness of the introduced improvement and ability of the proposed algorithm for finding better solutions compared to other presented methods. References 40, tables 3, figures 9.

Roseau Load Flow: a modern software package for the modelling and steady-state simulation of power distribution grids

Roseau Load Flow: a modern software package for the modelling and steady-state simulation of power distribution grids

Effect of PV Plants Connected to the Electrical Distribution System on the Mains Voltage

With the Paris Climate Agreement, incentives and demand for distributed generation are increasing day by day to reduce the carbon footprint, increase sustainability, and fight energy crises. However, since the current structure of the EDS is designed to be a one-way energy flow, the traditional grid evolves into a completely different structure with the connection to the distributed generation system. It is known that at the point where the distributed generation is connected to the system, it can have positive contributions to the grid as well as negative contributions. In this study, the effects of the generation-consumption relationship in the integration of PV power plants on the voltage on busbars, lines and transformers between the substation and the end user are investigated. Load flow analysis is performed with MatlabSimulink for two different generation-consumption cases and voltage variations are analyzed within the limits specified in the standards. The results of the analysis show that with the correct integration of PV plants, the grid voltage increases from 30.89 kV to 31.5 kV, which is the nominal voltage level, while with incorrect integration, it increased to 32.56 kV, an increase above the standards.

Application of the design space approach for optimal sizing and placement of distributed generation

Distributed generation relies on the generation and feeding of electrical power locally into the utility grid, thereby avoiding transmission and distribution losses in centralised generation and distribution. A methodology for the optimum sizing of distributed generators (DG) in a radial grid is proposed in this work. On the basis of distributed load flow analysis, the system performance, along with different constraints viz., the power stability index, branch current and voltage, the complete set of feasible design options, also known as the design space, has been identified. The design space of a distributed energy system identifies the entire solution set of DG rating, power loss and branch current within which a feasible system may be designed. The optimum size and placement of DG in the particular cases of 12-bus, IEEE 13-bus and IEEE 33-bus radial distribution systems are illustrated using the proposed approach. The optimum configuration is identified by minimising the total power losses as the objective function. The proposed approach is quick and gives a range of options rather than a single solution, thereby offering valuable insight into possible alternatives during the early stages of design.

Renewable DG allocation in a pre-scheduled grid power supply for different types of loads with and without distribution network reconfiguration

ABSTRACT This paper suggests a technique for dispatchable and non-dispatchable renewable distributed generation (DG) unit deployment under a constant quantity of power supply from the grid. It also accounts for seasonal fluctuations in load demand, solar and wind power generation. To analyse the scenario, the typical load flow approach is changed by inserting PQVδ and zero bus into the system. Three renewable DGs are used based on solar, wind and biomass to meet the load demand. Along with meeting the load demand, DG is operating to enhance the voltage profile and reduce the power loss. The research is conducted on a 33 and 69 bus distribution networks (DNRs) for constant power, constant current, constant impedance, composite and exponential or mixed load types. To reduce the loss even further, the networks are reconfigured in the presence of three different types of DGs. The suggested solution reduces loss by up to 54 % and allows for energy savings of up to 2.5546 × 10 7 kWh and 2.0719 × 10 7 kWh in 33 bus and 69 bus DNRs, respectively. Economic effectiveness is also analysed to indicate the profit earned from the DG installation. The uncertainty of solar and wind energy is also explored in this paper to see how the network responds to such a scenario.

A Fatigue Cohesive Law‐Embedded Finite‐Discrete Element Method for Pulsed Hydraulic Fracture Simulation

ABSTRACTThe pulsed hydraulic fracture (PHF) is a stimulation technique of reservoir, which can lower breakdown pressure by generating fatigue fracture. In this study, a fatigue cohesive law is proposed and embedded into the finite‐discrete element method (FDEM) to describe the fatigue failure of the interface under cyclic loading. The fatigue is assumed to result from the accumulation of plastic deformation, whose increment is related to the traction variation range of each cycle and the total plastic deformation. The proposed fatigue cohesive law is validated by the uniaxial compression and mixed‐mode three‐point bending test simulation. Then this fatigue cohesive law is embedded into a fully hydraulic–mechanical coupled FDEM to simulate the PHF. The influence of loading scheme, flow rate, frequency, viscosity and natural fracture density on PHF behaviors is discussed. The results suggest that both the pressure‐ and injection rate–controlled PHF can reduce the breakdown pressure. The flow rate, frequency, and viscosity have a great impact on the performance of PHF. The natural fractures surrounding a hydraulic fracture (HF) can be gradually activated under cyclic injection. The activated natural fractures contribute to the complicated HF network. These results indicate that the proposed fatigue cohesive model can effectively simulate the fatigue fracture of rock and HF propagation under cyclic injection.

Numerical study on clogging of porous asphalt pavement under the coupled action of vehicle vibration load and Rainwater Flow

ABSTRACT During the in-service use of porous asphalt pavement, debris can clog internal voids, impacting both its long-term performance and maintenance costs. Thus, understanding the clogging mechanism is crucial. This study introduces a novel approach to simulate clogging behavior by coupling the discrete element method (DEM) and computational fluid dynamics (CFD) to analyze various particulate clogging scenarios. The simulations included the effects of vehicle vibrations, the impact of rainwater seepage and their combination. The simulation results reveal that both vibration and rainwater significantly reduce clogging material mass, improving pavement permeability. Particles sized between 0.15 mm and 1.18 mm were identified as the most likely to cause clogging, with the tendency increasing alongside seepage velocity. This methodology provides a comprehensive framework for analyzing real-world clogging mechanisms and offers valuable insights for designing more durable and sustainable porous asphalt pavements.

Productivity Assessment of Digging and Loading Equipment (Cat 330D2L) and Hauling Equipment (Fuso 220PS) in Coal Mining at PT. Bhumi Sriwijaya Perdana Coal, Musi Banyuasin Regency, South Sumatra

PT. Bhumi Sriwijaya Perdana Coal, a coal mining company located in Musi Banyuasin District, South Sumatra, utilizes Caterpillar 330D2L excavators and Mitsubishi Fuso 220PS dump trucks for coal extraction activities. The company set a production target of 52,612 tons/month for March 2023. However, actual production fell short, with the hauling equipment achieving only 41,260.08 tons/month, despite the loading equipment exceeding the target with 59,086.93 tons/month. This research aims to identify factors hindering the achievement of production targets and propose strategies for improvement. The analysis revealed that the mismatch between the loader and hauler operations, reflected by a low match factor of 0.57, was a significant contributor to inefficiencies. Additional challenges included extended cycle times influenced by front-loading patterns, hauling path conditions, and equipment synchronization. After implementing improvements, including cycle time optimization and increased loading flow, the productivity of the Mitsubishi Fuso 220PS dump trucks increased to 59,732.67 tons/month. The match factor between the Caterpillar 330D2L and the Mitsubishi Fuso 220PS improved to 0.83, demonstrating enhanced operational alignment. These findings highlight the importance of addressing cycle times, optimizing equipment compatibility, and improving workflows to meet production targets effectively.

Analisa Aliran Daya pada Penyulang Sei Keruh di PT. PLN (PERSERO) UIWS2JB UP3 Jambi ULP Kuala Tungkal Menggunakan Software ETAP 12.6

In electric power systems, power flow studies are conducted to gather data on power flow. Including active and reactive power, voltage on each bus, voltage magnitude and phase angle, active and reactive power flowing through each channel, and the state of every piece of equipment to ascertain whether it satisfies the necessary standards for distributing the necessary electrical power. In this research, ETAP software is used to simplify and speed up the power flow calculation process. According to the analysis's findings, the higher the transformer load percentage, the smaller the voltage. The smallest voltage at point JE383 – JE507 which is located at the end of the line is 19,719 kV with an assumed load of 95%. The greater the transformer load percentage, the greater the current. The largest current is located at the base, namely at the PLTMG – JEX109 point of 49.2 A with an assumed load of 95%.

Innovative Photovoltaic-Aeration Integration: Enhancing Energy Efficiency and Grid Stability in Wastewater Treatment

Abstract This paper presents a detailed investigation into enhancing the energy efficiency of wastewater treatment plants (WWTPs) by integrating photovoltaic (PV) systems, emphasizing power flow analysis and experimental validation. Recognizing the substantial energy demands of aeration processes in WWTPs, this study proposes an innovative integration of PV panels with aeration tanks. This approach generates renewable energy and optimizes energy use through the thermal interaction between the PV panels and the aeration tanks. Key findings demonstrate a 15% overall increase in energy efficiency and a 5% improvement in PV efficiency due to aeration-induced cooling, along with a reduction in voltage fluctuations by up to 30% during high-demand periods. Additionally, the integration offsets approximately 20% of the WWTP's total energy consumption. The research is structured into two main components: a comprehensive power flow study using DIgSILENT PowerFactory and a laboratory experiment to validate the integration's effectiveness. The power flow analysis evaluates the electrical impact of PV integration on the WWTP's power grid, focusing on scenarios such as load fluctuations, grid disturbances, and the synchronization of PV generation with plant energy needs. The simulation results indicate that the integration significantly enhances the stability and efficiency of the plant's electrical system, reducing reliance on traditional energy sources. Concurrently, a laboratory experiment explored the practical effects of integrating PV systems with aeration tanks. The experiment demonstrated that the cooling effect provided by the aeration tanks leads to increased PV efficiency and notable energy savings. These experimental results align with the simulation findings, confirming the efficacy of this integrated approach. This study introduces a novel methodology for integrating renewable energy technologies into industrial processes, showcasing the potential for significant energy savings and improved operational efficiency in WWTPs. Future research will focus on scaling this integration strategy and assessing its long-term impacts on energy efficiency and wastewater treatment effectiveness.

Dynamic kinetic studies of lysozyme removal as protein waste using weak ion exchange nanofiber membranes in flow systems: Linear and nonlinear model analysis

Dynamic kinetic studies of lysozyme removal as protein waste using weak ion exchange nanofiber membranes in flow systems: Linear and nonlinear model analysis

Probabilistic load flow analysis for evaluation of photovoltaic grid connection applications

Uncertainty in power system analysis is increasing, mainly due to decentralized generation and the related spatial distribution of power plants, as well as the inherent volatility of renewable energy sources. In Austria, this development is reflected in a high number of photovoltaic grid connection applications in recent years. On the consumption side, there are changes in grid loads due to the increasing electrification of society, which is reflected, for example, in a rising number of electric vehicles. These aspects of uncertainty in generation and consumption must be considered in the planning process of distribution grids. A proper way to include uncertainty in the hosting capacity analysis of power grids are probabilistic load flow calculation methods. This paper provides an introductory overview of probabilistic load flow analysis, available calculation methods, required input parameters and the interpretation of results. This paper focuses on photovoltaics, so a correlation analysis of historical power generation measurements of spatially distributed photovoltaic power plants in Austria is presented. Furthermore, an insight into the development of Austrian photovoltaic grid connection applications from recent years is given.