Power System Design Research Articles

Parameter evaluation for a hybrid marine system combining solid oxide fuel cells and overexpanded steam-injected gas turbine

The article focuses on the development of decarbonized marine power systems, consisting of solid oxide fuel cells (SOFC) and gas turbines (GT), aiming to provide high economic and environmental performance. Currently, the potential of such systems is not fully realized due to issues related to the insufficient reliability and durability of the fuel cells themselves, as well as suboptimal heat utilization processes in the gas turbine section of the power plant. In contrast to previous research, this study demonstrates the prospects of using the steam-injected gas turbine (STIG) cycle and overexpanded turbine to improve the heat recovery conditions of exhaust gasses from fuel cells, enhance the efficiency of the power system, and increase the longevity of its key components. To achieve this, a corresponding mathematical model was developed, and optimization calculations for the proposed system cycle were conducted. Adopting the proposed cycle with a steam-injected gas turbine resulted in a 4.4 % increase in efficiency compared to traditional schemes. Such a system could be utilized in the design of advanced marine power system for the next generation.

Innovative Method for Reliability Assessment of Power Systems: From Components Modeling to Key Indicators Evaluation

Power systems comprise different electrical, electronic, electromechanical and electrochemical components. Adequacy, security, resilience and reliability represent essential requirements for grids functioning mode. The evaluation of such aspects can constitute a delicate task in the presence of heterogeneous components. Focusing on reliability assessment, several Reliability Prediction Models are available. They are suitably applied according to the type of component under evaluation. The lack of homogeneity of these models forbids the comparison of performance and identification of unreliable systems and grid section. This paper aims to face the mentioned issue proposing a unique reliability assessment methodology able to characterize different equipment connected to radial/meshed/ring grids and subjected to different stressing and ageing factors. It is customized for electrical lines, transformers, circuit breakers, converters and renewables plants. Component and systemic key indices are calculated. Furthermore, a novel “load feeding reliability“ indicator is evaluated for providing information about the supply reliability of a specific load. This index is meaningful for the identification of unreliable grids, microgrids and systems. Such an approach can contribute to improve power systems design, planning and control. The proposed method is integrated in a software application implemented for grid reliability assessment. The obtained results are reported for an urban grid including an underground transportation area.

Design and Analysis of Power and Transmission System of Downhole Pure Electric Command Vehicle

Design and Analysis of Power and Transmission System of Downhole Pure Electric Command Vehicle

Bio-Inspired Design of Future Solar Power Systems for Smart Grid Applications

Bio-Inspired Design of Future Solar Power Systems for Smart Grid Applications

Transformation of the model of the design scheme of the power system in the problem of ensuring balance reliability

The paper deals with the issues reducing the number of territorial zones in the model calculation scheme UPS of Russia as applied to the problem of substantiating the required generating capacity (capacity reserve) under the conditions of ensuring normative indicators of balance reliability in accordance with the requirements of the new guidelines for design of power systems. On the example of the model UPS of Russia calculation scheme developed by SO UPS specialists, the possibilities of reducing the number of territorial zones to reasonable limits are shown.

A Novel Railway Power Systems Design Methodology Using Genetic Algorithms: Models and Application

A Novel Railway Power Systems Design Methodology Using Genetic Algorithms: Models and Application

Traceless Kalman filter threshold estimation for distributed power loads

Abstract Load forecasting is an important part of smart grid construction, energy management, and sustainable design of power systems, and has a great impact on the reliable operation of power grids, facility planning and other decisions. In this paper, we utilize the traceless transform of the UKF algorithm to obtain the sigma feature points generated by the mean value of the high-frequency wavelet components of the power signals and combine them with the EKF algorithm. We put forward a novel neural network hybrid Kalman TUKF algorithm, which will be used to carry out simulation experiments on the distributed electric loads and to estimate the threshold value of the loads in the numerical experiments. The results show that in comparison with the actual measurements, the TUKF algorithm improves by 34.7% in the RMSE metrics, 38.7% in the MAE metrics, and 40.6% in the MAPE metrics compared to the PFWNN. The TUKF algorithm is closer to the real curves and has the best prediction performance for all the time intervals of the prediction. The change of the threshold value has a more obvious effect on the prediction accuracy, and the best effect is in the scale δ = 0.5, i.e., the threshold frequency is selected as the middle value of the intermediate frequency.

A convolutional neural network framework to design power system stabilizer for damping oscillations in multi-machine power system

A convolutional neural network framework to design power system stabilizer for damping oscillations in multi-machine power system

Reliability Assessment of Statistical Distributions for Analyzing Dielectric Breakdown Strength of Polypropylene

Various statistical distributions, such as Weibull, log-normal, and exponential functions, are frequently employed to interpret the dielectric breakdown (BD) strength data of insulating materials, including cross-linked polyethylene, low-density polyethylene, polypropylene (PP), and polyethylene. This study aimed to determine a suitable statistical distribution for analyzing the dielectric BD strength data of PP insulators before and after thermal degradation. Dielectric BD strength tests were conducted on thermally deteriorated PP insulators under various degradation conditions. Additionally, a coefficient of determination was employed to assess the compatibility between the dielectric BD strength data and the statistical distribution of PP insulators before and after thermal degradation. The test results indicate that the coefficient of determination for alternating current BD strength data was 0.955 in the log-normal distribution before degradation and 0.929 in the Weibull distribution after degradation. Consequently, in the analysis of the PP insulation breakdown data, the log-normal distribution was found to be suitable for data before degradation, while the Weibull distribution was deemed suitable for data after degradation. These results can lead to lower errors in the power system design process, enhancing reliability when analyzing the BD strength data of insulation materials.

Simulated Design and Evaluation of Centralized off Grid Street Light Solar Power System with Backup Generator

In this paper, simulated design and evaluation of centralized off grid street light solar power system with backup generator is presented. The design of the street light solar power system takes into consideration the desired illumination level, the width of road, the coefficient of utilization, the maintenance factor, the desired distance between street light poles, the pole height, the pole space to pole height ratio and the total length of the street. The case study street light is located along IBB Avenue in Uyo, with latitude and longitude of 5.016982, 7.911769 respectively, path length of 2.2 km and daily energy demand of 125.8 kWh/day. The PVSyst simulation results show that the solar fraction is 0.993 which indicates that 99.3 % of the energy demand of the street light is supplied from the solar power while the remaining 0.7% of the energy demand is supplied form the backup generator. The total energy supplied by the generator is 375.7 kWh whereas the total annual energy generated from the PV array is 53739 kWh. The annual total of the energy demand is 46059 kWh while the annual total of the energy supplied to the street light from the solar power system is 46027 kWh. Also, the annual mean of the battery state of charge (SoC) is 80.3 %. Also, it is noted that the month of August alone has about 375.7 kWh energy supply from the backup generator with about 98 liters of fuel. Specifically, in a whole year, the backup generator will be used for only three days in August, namely, on the 13th, 14th and 15th of August, with the maximum supply of 239.8012 kWh occurring on the 14th day of August. Furthermore, the performance ratio (PR) of the system is 48.5%. In all, the results show that the solar power system is able to supply the required energy demand of the case study street light with only 0.7% deficit which is supplied from the backup generator.

Design and Application of New Support and Power System of Residential Building Machine

In recent years, with the transformation and upgrading of national development and the acceleration of urbanization, the construction mode of high energy consumption, high pollution and high labor intensity in the construction industry can no longer meet the development needs. The State Council and the Ministry of Housing and Urban-Rural Development have successfully issued policies and initiatives to improve industrialization and intelligent construction. In 2021, the Ministry of Housing and Urban-Rural Development issued a building height limit order, and it has become a trend that aerial building machines have begun to diversify into ordinary high-rise residences. The "14th Five-Year Plan" construction industry development plan issued by the Ministry of Housing and Urban-Rural Development proposed accelerating the coordinated development of intelligent construction and new building industrialization and promoting digital design, intelligent production and intelligent construction. In response to the national policy guidance and leading the development of the industry, solve the inherent problems in the construction industry, learn from the application concept of super high-rise heavy-duty construction equipment integration, create a "factory-like" construction environment for ordinary high-rise through lightweight, standardization and intelligent and other innovative technologies, and explore a construction integration platform suitable for high-rise residences, called "high-rise building industrialization construction lightweight construction operation integration platform" (referred to as "building machine"). Based on the first generation of building construction machines, continuous improvement and replacement, the supporting power system has dramatically improved in support capacity and lightweight. The effective combination of a support column, hydraulic cylinder, and pump station has been realized, which is more convenient and faster, and the construction is more efficient.

Conceptual design of a novel megawatt portable nuclear power system by supercritical carbon dioxide brayton cycle coupled with heat pipe cooled reactor

In order to meet realistic requirements for flexible and reliable power supply in special scenarios such as remote areas and deep ocean exploration, a novel megawatt portable nuclear power system called SUPERHERO (SUPERcritical carbon dioxide cycle-HEat pipe ReactOr power system) is proposed in this paper. The system consists of a heat pipe-cooled reactor and a closed supercritical carbon dioxide (S–CO2) Brayton power cycle. Different cycle concepts were compared, and the simple recuperated cycle was adopted for compactness and simplicity of the system. The multi-objective optimization is performed to maximize cycle efficiency and minimize system volume, resulting in optimized parameters for a 1MWe system. By utilizing uranium nitride (UN) modular fuel elements and high heat transfer capacity potassium heat pipes, a compact reactor scheme with 3.13MWt is determined that can operate for 15 years without refueling. The neutronics and thermal analysis of the reactor are carried out, and the results show that the reactor has safety features such as a low peak factor, negative temperature feedback coefficient, sufficient reactivity compensation and control, and anti-failure of single heat pipe. The primary heat exchanger is also designed using the CFD method, and the heat exchange tubes combined with ribbed plates and self-supporting structures are used to enhance heat transfer and ensure structural stability. All these studies outline the general features of SUPERHERO, demonstrating that SUPERHERO has great development potential.

A Comprehensive Evaluation Method for Planning and Design of Self-Sufficient Wind Power Energy Systems at Ports

This study proposes a scientific method to assess the rationality of planning and design of self-sufficient wind power systems (SS-WPSs) at ports. The evaluation method proposed is based on the concept of integrated development of water transportation and a clean energy system, taking into account the demand of the former and the availability of the latter. First, the factors representing the property of the system from the perspectives of economy, environment, energy efficiency, self-sufficiency, and reliability are calculated. The evaluation method is developed by using a combined Analytical Hierarchy Process and Entropy Weight Method (AHP-EWM) to calculate the subjective and objective weights of these factors. Subsequently, a combined weighting method based on game theory is employed with the aim of minimizing deviations between the subjective and objective weights and the combination weights, thereby determining the optimal combination of weights of the evaluation factors. These weights will be used to calculate evaluation results under different planning schemes. To validate the effectiveness of the method, a case study is developed based on a wind power energy demonstration project at a dock of a container port. Study results reveal that Option C, considered in this study, outperforms other options with the highest evaluation score of 0.737. Sensitivity analysis further underscores the reliability of Option C, showing a robust 96.15% probability of achieving the maximum final score within a 20% variation range. This indicates that the case study demonstrates that intuitive and realistic evaluation results can be obtained from the proposed method. These results affirm the practicality of our approach, providing invaluable insights for planners, policymakers, and stakeholders involved in sustainable energy initiatives.

Developing a collector system aggregation technique of a large-scale grid-connected wind farm

The increasing complexity of power systems necessitates the development of aggregation techniques to address specific issues. Model reduction is crucial to expand simulation capacity, ensuring the stability and reliability of power system design. This paper presents a collector system full aggregation technique based on the per unit system model and power loss-based aggregation technique applied to the impedance model of a large-scale grid-connected Wind Farm (WF). The purpose of the proposed technique is to obtain a fully aggregated equivalent representation of the WF collector system, which includes High Voltage (HV) three-winding transformer(s) or more than one HV two-winding transformer, to reduce the simulation time and the system complexity while maintaining similar performance compared to the Detailed Model (DM) and high-accuracy results in both steady-state and dynamic conditions. To be validated, the presented Per Unit Full Aggregation (PUFA) technique is used to obtain a Full Aggregated Equivalent Model (FAEM) of the existing Gabel El-Zeit WF, Egypt, Detailed Model (DM) that contains two HV three-winding transformers. The PUFA model is tested using the DIgSILENT PowerFactory software package, leading to a significant reduction in model order and simulation time with respect to the DM. The PUFA technique is compared to the DM and other aggregated models in terms of power flow using Quasi-Dynamic Simulation (QDS), dynamic response using Low Voltage Right Through (LVRT) simulation, Modal Analysis (MA), and small signal simulation. The comparison between the different models and the proposed one has confirmed that it realizes very competitive results with high accuracy in both steady-state and dynamic conditions with the least simulation time.

A novel framework for interconnected hybrid power system design using hybridization of metaheuristic algorithms and fuzzy inference

ABSTRACT In this study, load frequency control (LFC) of an interconnected isolated hybrid power system (IHPS) with different power generating units (PUGs) like a diesel engine generator (DEG), a combined cycle gas turbine (CCGT), and a wind turbine generator (WTG) are integrated for more sustainable energy. Proportional-integral-derivative (PID) and fuzzy PID (FPID) controllers are employed for governor speed control of DEG and CCGT and pitch control of WTG to enhance system stability. The study is focused on optimizing the controller parameters to match power output with load demand, ensuring stable system frequency under various load and wind perturbations. Two optimization algorithms, the student psychology-based optimization algorithm (SPBOA) and the quasi-oppositional based whale optimization algorithm (QOWOA), are utilized to optimize controller gains. The integral of time absolute error served as the objective function to assess the effectiveness of the proposed SPBOA (for PID and FPID-based) and QOWOA (for PID and FPID-based) models. Comparative analysis revealed that the SPBOA-based IHPS model demonstrated superior response in terms of objective function, settling time, and peak, particularly outperforming the QOWOA-based model across different scenarios. Notably, the SPBOA-FPID controller exhibited enhanced dynamic responses and overall performance compared to SPBOA-based PID, fuzzy proportional-integral, and fuzzy proportional-derivative controllers.

Study on start-up characteristics of a heat pipe cooled reactor coupled with a supercritical CO2 Brayton cycle

The new megawatt nuclear power system coupling a heat pipe cooled reactor with a supercritical CO2 Brayton cycle is considered one of the most promising energy conversion systems for large Unmanned Undersea Vehicles (UUVs). This system combines the characteristics of a heat pipe cooled reactor and a S-CO2 Brayton cycle, such as heat pipe start-up limitations and significant thermal inertia. It is unclear whether existing start-up control strategies for either heat pipe cooled reactors or S-CO2 Brayton cycle are suitable for this new system. Therefore, the start-up characteristics and the control strategies of the new megawatt nuclear power system are investigated in this study. A simulation code is developed for the study of the start-up characteristics of this system, which includes models for the reactor, heat pipes, and the S-CO2 Brayton cycle. The validation of the code is conducted based on the experiments as well as the design values. Good agreement between the calculation results and the experimental values or the design values are obtained. And then, the control scheme and start-up strategy of the new system are proposed. The start-up process is divided into four sub-stages, that is, core start-up from cold to critical state, heat pipes start-up, compressor start-up and turbine preheating, and branch switching. Different control strategies are applied to each sub-stage. The results show that the shaft raising rate of 2000 rpm/min is effective in overcoming expansion resistance without causing excessive overshoot in mass flowrate. This control strategy can achieve stable start-up of the new system without exceeding a temperature change rate of 10 K/min. This research may serve as a reference for the conceptual design of this new megawatt nuclear power system.

Comparative Analysis of Various Controllers used for Automatic Generation Control in Electrical Power Systems

In the rapidly evolving landscape of power systems, achieving a stable and efficient Automatic Generation Control (AGC) remains paramount. The exigency for this research stems from the critical role AGC plays in maintaining frequency and power balance amidst dynamic system changes. The consequences of inadequacies in AGC manifest as frequency deviations, system instabilities, and potential blackouts, with widespread socio-economic implications for different use cases. Historically, various controllers have been proposed and implemented to address AGC challenges. However, existing methodologies have displayed inherent limitations. Predominant issues include lack of adaptability to non-linearities, slow response times, inability to cater to the multifaceted nature of modern power grids with renewable integrations, and susceptibility to uncertainties and disturbances. This comprehensive review delves deep into the spectrum of controllers available for AGC, encompassing conventional PI/PID controllers, robust controllers, adaptive controllers, intelligent controllers, and the more recent forays into neural network-based and fuzzy logic controllers. Each controller's salient features, operational dynamics, advantages, and shortcomings are meticulously dissected. Furthermore, this paper elucidates the contexts in which each controller type excels or is found wanting, providing invaluable guidance for system designers and operators. In essence, this review serves as a holistic compass for stakeholders involved in power system operation and design. It offers both a retrospective understanding and prospective insights, assisting decision-makers in choosing the most suitable controller for a given scenario. Whether one aims to optimize AGC for a traditional grid, a grid with high renewable penetration, or a hybrid system, this paper promises to be an indispensable reference for researchers.

Synergies and Trade-Offs in Hybrid Propulsion Systems Through Physics-Based Electrical Component Modeling

Abstract Hybrid-electric propulsion is recognized as an enabling technology for reducing aviation's environmental impact. In this work, a serial/parallel hybrid configuration of a 19-passenger commuter aircraft is investigated. Two underwing-mounted turboprop engines are connected to electrical branches via generators. One rear fuselage-mounted electrically driven ducted fan is coupled with an electric motor and respective electrical branch. A battery system completes the selected architecture. Consistency in modeling accuracy of propulsion systems is aimed for by development of an integrated framework. A multipoint synthesis scheme for the gas turbine and electric fan is combined with physics-based analytical modeling for electrical components. Influence of turbomachinery and electrical power system design points on the integrated power system is examined. An opposing trend between electrical and conventional powertrain mass is driven by electric fan design power. Power system efficiency improvements in the order of 2% favor high-power electric fan designs. A trade-off in electrical power system mass and performance arises from oversizing of electrical components for load manipulation. Branch efficiency improvements of up to 3% imply potential to achieve battery mass reduction due to fewer transmission losses. A threshold system voltage of 1 kV, yielding 32% mass reduction of electrical branches and performance improvements of 1–2%, is identified. This work sets the foundation for interpreting mission-level electrification outcomes that are driven by interactions on the integrated power system. Areas of conflicting interests and synergistic opportunities are highlighted for optimal conceptual design of hybrid powertrains.

Optimal Design of a Hybrid Power System for a Remote Fishpond Based on Hydro-Turbine Performance Parameters

This paper proposes an optimal solution for the design of a hybrid power system that will supply a remote fishpond in eastern Serbia. In terms of structure, this off-grid system should be a hydro-photovoltaic-diesel-converter-battery setup. The optimization objectives are to minimize total net present cost (NPC) and greenhouse gas (GHG) emissions and to maximize total annual electricity generation based on the modification of hydro-turbine performance. This study considers the following three cases of a hydro-turbine with fixed propeller blades: having fixed guide vanes, for the annual average flow rate-Case 1; having adjustable guide vanes, for smaller flow rates-Case 2 and having adjustable guide vanes, for higher flow rates-Case 3. The optimization is performed using HOMER Pro v. 3.16.2 software. The results show that the total NPC, levelized cost of energy (COE) and GHG emissions in Case 3 are 16.6%, 16.8% and 13.1% lower than in Case 1, and 8.1%, 8% and 11.7% lower than in Case 2, respectively. It is also found that the total annual electricity generation and power output from the entire system in Case 3 are 33.3% and 1.2% higher than in Case 1, and 11.9% higher and not different than in Case 2, respectively.

High-performance computing for static security assessment of large power systems

Contingency analysis (CA) is one of the essential tools for the optimal design and security assessment of a reliable power system. However, its computational requirements rise with the growth of distributed generations in the interconnected power system. As CA is a complex and computationally intensive problem, it requires a fast and accurate calculation to ensure the secure operation. Therefore, efficient mathematical modelling and parallel programming are key to efficient static security analysis. This paper proposes a parallel algorithm for static CA that uses both central processing units (CPUs) and graphical processing units (GPUs). To enhance the accuracy, AC load flow is used, and parallel computation of load flow is done simultaneously, with efficient screening and ranking of the critical contingencies. We perform extensive experiments to evaluate the efficacy of the proposed algorithm. As a result, we establish that the proposed parallel algorithm with high-performance computing (HPC) computing is much faster than the traditional algorithms. Furthermore, the HPC experiments were conducted using the national supercomputing facility, which demonstrates the proposed algorithm in the context of N−1 and N−2 static CA with immense power systems, such as the Indian northern regional power grid (NRPG) 246-bus and the polish 2383-bus networks.