Browse
Subjects
Records with Subject: Energy Management
Showing records 245 to 269 of 1388. [First] Page: 1 7 8 9 10 11 12 13 14 15 Last
Investigation of Smart Grid Operation Modes with Electrical Energy Storage System
Oleksandr Miroshnyk, Oleksandr Moroz, Taras Shchur, Andrii Chepizhnyi, Mohamed Qawaqzeh, Sławomir Kocira
April 18, 2023 (v1)
Keywords: distribution network, electricity storage system, modeling of network modes, power balance, Smart Grid
The paper considers the issues of maintaining an equality of flow in generated and consumed electric energy in an electric network incorporating an electric power storage system. An analysis of ways to equalize the energy and power balance was carried out, and the advantages of using electricity storage systems in electrical networks was assessed. Upon simulation using the Power Factory program, we noted that, after switching on the load, a transient process occurs, characterized by a jump in active power, which was caused by the need for time to initiate the electric energy storage system. However, immediately after this, the process of issuing the accumulated energy to the electrical network and compensating for energy consumption began. Moreover, when the load was disconnected, there is a certain dip in the active power curve and a further increase in consumption. This was found to be due to the transition of the electricity storage system to the modes of energy storage and battery... [more]
Impact of Household PV Generation on the Voltage Quality in 0.4 kV Electric Grid—Case Study
Peteris Apse-Apsitis, Oskars Krievs, Ansis Avotins
April 18, 2023 (v1)
Keywords: harmonics, inverters, photovoltaic, power quality, solar energy, THD
This article (case study) discusses the influence of household photovoltaic generation on the voltage quality in a three-phase 0.4 kV grid. The research analyzes remotely acquired data from two specially designed three-phase Y-connected power meters to understand the PV system’s influence on the grid. The values of the voltages, currents, THD, individual harmonics, power factor, and K-factor are obtained every 200 ms over several months, creating more than 20 GB of data. The loads are typical household electrical appliances and EV portable chargers. The main conclusion after analyzing the measurements is that three-phase PV generation in the presence of household loads can create or increase grid unbalance; important current values into the neutral wire and THD and K-factor increase in some cases. The results also uncovered that without current sensing at the household connection point to the three-phase grid to control the PV inverter, the balanced phase output power of the grid-tied... [more]
Maximizing the Integration of a Battery Energy Storage System−Photovoltaic Distributed Generation for Power System Harmonic Reduction: An Overview
Adedayo Owosuhi, Yskandar Hamam, Josiah Munda
April 18, 2023 (v1)
Keywords: battery energy storage system, distribution network system, harmonic distortions, optimization methodologies, photovoltaic distributed generation
The highly variable power generated from a battery energy storage system (BESS)−photovoltaic distributed generation (PVDG) causes harmonic distortions in distribution systems (DSs) due to the intermittent nature of solar energy and high voltage rises or falls in the BESS. Harmonic distortions are major concerns in the DS, especially when the sizes and locations of these resources are sub-optimal. As a result, many studies are being performed on the optimal allocation of BESS/PVDG systems in distribution network systems. In this regard, this paper seeks to review the existing planning models, optimization methods and renewable energy resources that uncertainty models have employed in solving BESS/PVDGs allocation problems in terms of obtaining optimal solutions/allocations and curtailing the harmonic contents of the DSs. However, studies on optimal allocation planning of BESS/PVDGs have achieved minimum cost but were not able to meet the standard harmonic level of the DSs. The results i... [more]
Peer-to-Peer Electrical Energy Trading Considering Matching Distance and Available Capacity of Distribution Line
Natnaree Tubteang, Paramet Wirasanti
April 18, 2023 (v1)
Keywords: congestion management, electricity energy market, matching approach, peer-to-peer energy trading
The concept of peer-to-peer (P2P) energy trading leads to the flexible energy transaction of prosumers and consumers, for which the P2P business model is normally the main attention. It still requires system operators to address the challenges in trading and constraint problems. In this context, this work regards the congestion constraint in conjunction with energy trading. Firstly, a matching approach based on the cost path is proposed. It is consistent with the cost for the dispatch along each route, making a suitable matching in both distance and bids. In combination with the matching process, the available capacity has to be considered to avoid line congestion. Secondly, the bus transfer factor (BTF) and the partitioning zone approach are proposed to overcome the issue. BTF refers to a response of bus power to the congested line power. The partitioning zone, separated into the source and the load area, enables a simple management strategy. Thereby, the power adjustment in each area... [more]
A High Frequency Multiphase Modular Hybrid Transformerless DC/DC Converter for High-Voltage-Gain High-Current Applications
Hu Xiong, Jiayuan Li, Bin Xiang, Xiaoguang Jiang, Yuan Mao
April 18, 2023 (v1)
Keywords: cost-effective, DC microgrids, high efficiency, high-frequency hybrid converter, high-voltage conversion ratio, low-voltage-stress
In order to meet the demands of desirable efficiency, transformerless DC/DC equipment with great voltage step-down are inevitable needed. This research offers a unique type of high-frequency, high-voltage-gain DC/DC converter, which comprises a switched capacitor (SC) converter and a buck converter. Thanks to the transformation of a two-stage converter to a single-stage converter, it has a considerable ratio of step-down voltage transformation and a reasonable duty cycle. In addition, it can permit low voltage stress on the switches. The simple control method and easy driving circuit implementation makes it scalable for high-power-level devices. Low cost can be realized as fewer components are needed. Under all operational circumstances, total soft-charging and low equipment voltage stresses are accomplished. Compared to those classic high-voltage-gain converters, the proposed converter exhibits merits of higher efficiency, higher flexibility, lower ripples, and lower costs. A comprehe... [more]
Multiple Load Forecasting of Integrated Energy System Based on Sequential-Parallel Hybrid Ensemble Learning
Wenxia You, Daopeng Guo, Yonghua Wu, Wenwu Li
April 17, 2023 (v1)
Keywords: ensemble learning, grid search, load forecasting of integrated energy system, maximum information coefficient
Accurate multivariate load forecasting plays an important role in the planning management and safe operation of integrated energy systems. In order to simultaneously reduce the prediction bias and variance, a hybrid ensemble learning method for load forecasting of an integrated energy system combining sequential ensemble learning and parallel ensemble learning is proposed. Firstly, the load correlation and the maximum information coefficient (MIC) are used for feature selection. Then the base learner uses the Boost algorithm of sequential ensemble learning and uses the Bagging algorithm of parallel ensemble learning for hybrid ensemble learning prediction. The grid search algorithm (GS) performs hyper-parameter optimization of hybrid ensemble learning. The comparative analysis of the example verification shows that compared with different types of single ensemble learning, hybrid ensemble learning can better balance the bias and variance and accurately predict multiple loads such as el... [more]
Day-Ahead Electricity Market Price Forecasting Considering the Components of the Electricity Market Price; Using Demand Decomposition, Fuel Cost, and the Kernel Density Estimation
Arim Jin, Dahan Lee, Jong-Bae Park, Jae Hyung Roh
April 17, 2023 (v1)
Keywords: Artificial Intelligence, data preprocessing, decomposition, electricity market, feature selection, price forecast
This paper aims to improve the forecasting of electricity market prices by incorporating the characteristics of electricity market prices that are discretely affected by the fuel cost per unit, the unit generation cost of the large-scale generators, and the demand. In this paper, two new techniques are introduced. The first technique applies feature generation to the label and forecasts the transformed new variables, which are then post-processed by inverse transformation, considering the characteristic of the fuel types of marginal generators or prices through two variables: fuel cost per unit by the representative fuel type and argument of the maximum of Probability Density Function (PDF) calculated by Kernel Density Estimation (KDE) from the previous price. The second technique applies decomposition to the demand, followed by a feature selection process to apply the major decomposed feature. It is verified using gain or SHapley Additive exPlanations (SHAP) value in the feature selec... [more]
Simplified Method for Predicting Hourly Global Solar Radiation Using Extraterrestrial Radiation and Limited Weather Forecast Parameters
Xinyu Yang, Ying Ji, Xiaoxia Wang, Menghan Niu, Shuijing Long, Jingchao Xie, Yuying Sun
April 17, 2023 (v1)
Keywords: extraterrestrial solar radiation, hourly global solar radiation, LightGBM, SHAP analysis, simplified prediction method
Solar radiation has important impacts on buildings such as for cooling/heating load forecasting, energy consumption forecasting, and multi-energy complementary optimization. Two types of solar radiation data are commonly used in buildings: radiation data in typical meteorological years and measured radiation data from meteorological stations, both of which are types of historical data. However, it is difficult to predict the hourly global solar radiation, which affects the application of relevant prediction models in practical engineering. Most existing methods for predicting hourly global solar radiation have issues such as difficulty in obtaining input parameters or complex data processing, which limits their practical engineering applications. This study proposed a simplified method to accurately predict the hourly horizontal solar radiation using extraterrestrial solar radiation, weather types, cloud cover, air temperature, relative humidity, and time as the input parameters. The b... [more]
Impact Assessment of Electric Vehicle Charging in an AC and DC Microgrid: A Comparative Study
Rémy Cleenwerck, Hakim Azaioud, Majid Vafaeipour, Thierry Coosemans, Jan Desmet
April 17, 2023 (v1)
Keywords: converter efficiency, DC microgrid, electric vehicles, LVDC backbone, power quality
This paper presents an in-depth comparison of the benefits and limitations of using a low-voltage DC (LVDC) microgrid versus an AC microgrid with regard to the integration of low-carbon technologies. To this end, a novel approach for charging electric vehicles (EVs) on low-voltage distribution networks by utilizing an LVDC backbone is discussed. The global aim of the conducted study is to investigate the overall energy losses as well as voltage stability problems on DC and AC microgrids. Both architectures are assessed and compared to each other by performing a power flow analysis. Along this line, an actual low-voltage distribution network with various penetration levels of EVs, combined with photovoltaic (PV) systems and battery energy storage systems is considered. Obtained results indicate significant power quality improvements in voltage imbalances and conversion losses thanks to the proposed backbone. Moreover, the study concludes with a discussion of the impact level of EVs and... [more]
Energy Behaviors of Prosumers in Example of Polish Households
Bożena Gajdzik, Magdalena Jaciow, Radosław Wolniak, Robert Wolny, Wieslaw Wes Grebski
April 17, 2023 (v1)
Keywords: energy behavior, energy sector, households, Poland, prosumer, responsible consumption
This paper explores ways to save energy in households with energy prosumers who generate energy using photovoltaic panels and heat pumps. On the basis of a literature analysis, we formulated a research gap in the case of the energy behaviors of prosumers. This research is important due to the growing demand for energy and the transitions of countries toward renewable energy sources. The role of prosumers in the economy is growing as they ensure energy independence and cost savings. The main purpose of this research is to understand the energy behaviors of prosumers and to examine the differences in energy behaviors between users of photovoltaic systems and heat pumps. A sample of 326 Polish prosumer households was selected using the CAWI method in order to obtain empirical data. The results suggest that prosumers show advanced ecological behaviors, and more than half of the respondents implement pro-ecological behaviors in their homes. Being a prosumer is associated with energy indepen... [more]
Structure Optimization of Ensemble Learning Methods and Seasonal Decomposition Approaches to Energy Price Forecasting in Latin America: A Case Study about Mexico
Anne Carolina Rodrigues Klaar, Stefano Frizzo Stefenon, Laio Oriel Seman, Viviana Cocco Mariani, Leandro dos Santos Coelho
April 17, 2023 (v1)
Keywords: electricity spot prices, ensemble learning methods, Latin America, seasonal decomposition, time series forecasting
The energy price influences the interest in investment, which leads to economic development. An estimate of the future energy price can support the planning of industrial expansions and provide information to avoid times of recession. This paper evaluates adaptive boosting (AdaBoost), bootstrap aggregation (bagging), gradient boosting, histogram-based gradient boosting, and random forest ensemble learning models for forecasting energy prices in Latin America, especially in a case study about Mexico. Seasonal decomposition of the time series is used to reduce unrepresentative variations. The Optuna using tree-structured Parzen estimator, optimizes the structure of the ensembles through a voter by combining several ensemble frameworks; thus an optimized hybrid ensemble learning method is proposed. The results show that the proposed method has a higher performance than the state-of-the-art ensemble learning methods, with a mean squared error of 3.37 × 10−9 in the testing phase.
Extended Operating Region Algorithm for PV Array Connected to Microgrids for Wide Frequency and Amplitude Variations
Matías Garbarino, Jaime Rohten, Rodrigo Morales, José Espinoza, Javier Muñoz, José Silva, David Dewar
April 17, 2023 (v1)
Keywords: DC/AC converter, microgrids, MPPT, operation region, overmodulation control, PLL
The employment of microgrids and distributed power generation have exponentially increased over recent decades, due in part to the increased inclusion of renewable energies as these technologies become cheaper to install. However, microgrids are highly sensitive to power variation, leading to distortion of the grid voltage (amplitude and frequency changes) which could destabilize the entire microgrid under variation of loads and/or other power sources. In this context, a new control strategy is proposed for a photovoltaic grid connected system, operating under voltage variations typical of a low inertial electric power network. The main problem related to voltage fluctuation is that the variables may take the power converter out of the operating region, and therefore, all controllers, including the maximum power point tracking, will not work as designed. The analysis, based on the mathematical operating region, demonstrates that the control strategy can include overmodulation compensat... [more]
Assessment of Conservation Voltage Reduction in Distribution Networks with Voltage Regulating Distribution Transformers
Anthony Igiligi, Armin Vielhauer, Mathias Ehrenwirth, Christian Hurm, Thorsten Summ, Christoph Trinkl, Daniel Navarro Gevers
April 17, 2023 (v1)
Keywords: conservation voltage reduction, peak power, tap change, voltage regulating distribution transformers
The application of voltage reduction in medium and low voltage grids to reduce peak power demand or energy consumption has been implemented since the 1980s using several approaches. Conservation Voltage Reduction (CVR), as one such approach, uses a voltage control device to reduce or increase the voltage setpoint on a busbar, thereby reducing or increasing the amount of active and reactive power supply in the network. Voltage regulation for CVR is always implemented according to established network planning standards in each country. Research in this field has proven that a CVR factor (CVRf) of 0.7−1.5 for peak demand reduction can be achieved. This is an evaluation metric of CVR. The aim of this research is to determine and validate CVRf for peak demand reduction by comparing actual results obtained during regular tap changes with other randomly distributed periods outside tap change operations, using a set of measurement data. It is important to understand CVR deployment capability b... [more]
State-of-the-Art Literature Review of Power Flow Control Methods for Low-Voltage AC and AC-DC Microgrids
Pavel Ilyushin, Vladislav Volnyi, Konstantin Suslov, Sergey Filippov
April 17, 2023 (v1)
Keywords: control action, converter, distributed energy resources, generating set, inverter, microgrid, power flow control, renewable energy sources
The development of AC distribution systems provides for the seamless integration of low-voltage microgrids with distributed energy resources (DERs). This poses new challenges for the control of normal, emergency, and post-emergency states of microgrids, calling for the creation and development of information and communications technology infrastructure. Power converters/inverters that are used to integrate renewable DERs lack inertia. Along with them, fossil fuel-fired generation units are also being integrated into microgrids. These include gas generator sets, diesel generator sets, and microturbines, having small (up to 1−2 s) values of mechanical inertia constants—Tj. This leads to an increase in the rate of transients by a factor of 5−10. Under these conditions, the technical requirements for the speed of automatic power flow control systems, as well as the methods they rely on, have to be reconsidered. Microgrids include DC microgrids, AC microgrids, and hybrid (AC-DC) microgrids.... [more]
Research on Load State Sensing and Early Warning Method of Distribution Network under High Penetration Distributed Generation Access
Cailian Gu, Yibo Wang, Weisheng Wang, Yang Gao
April 17, 2023 (v1)
Keywords: distributed power supply, load flow analysis, new energy, power system
Aiming at the problems of power flow fluctuation and voltage exceeding standard caused by high permeability distributed power supply access, this paper proposes a load state perception early warning method for distribution networks. Firstly, the random behavior characteristics and voltage early warning mechanisms of power supply and load in distribution networks are analyzed, the dynamic model of distribution networks based on complex network theory is established, and the risk index of voltage exceeding limits under the conditions of high permeability distributed power supply access is put forward. Secondly, the random power flow of distribution networks based on the Monte Carlo method is studied by sampling and analyzing the dynamic model of distribution networks. Then, the risk calculation and safety assessment of voltage exceeding limits are carried out on the currently extracted model, and the risk control strategy of distribution network operation is put forward. Finally, an impr... [more]
Power-Load Forecasting Model Based on Informer and Its Application
Hongbin Xu, Qiang Peng, Yuhao Wang, Zengwen Zhan
April 17, 2023 (v1)
Keywords: deep learning, Informer, power-load forecasting, self-attention mechanism, time series
Worldwide, the demand for power load forecasting is increasing. A multi-step power-load forecasting model is established based on Informer, which takes the historical load data as the input to realize the prediction of the power load in the future. The constructed model abandons the common recurrent neural network to deal with time-series problems, and uses the seq2seq structure with sparse self-attention mechanism as the main body, supplemented by specific input and output modules to deal with the long-range relationship in the time series, and makes effective use of the parallel advantages of the self-attention mechanism, so as to improve the prediction accuracy and prediction efficiency. The model is trained, verified and tested by using the power-load dataset of the Taoyuan substation in Nanchang. Compared with RNN, LSTM and LSTM with the attention mechanism and other common models based on a cyclic neural network, the results show that the prediction accuracy and efficiency of the... [more]
Survey of Sustainable Energy Sources for Microgrid Energy Management: A Review
Mohammed Amine Hoummadi, Manale Bouderbala, Hala Alami Aroussi, Badre Bossoufi, Najib El Ouanjli, Mohammed Karim
April 17, 2023 (v1)
Keywords: energy management, Energy Storage, microgrids, Renewable and Sustainable Energy
Renewable energy sources are nowadays a viable choice to satisfy the rising energy consumption and promote the advancement of sustainable development. These systems are integrated into microgrids using a variety of technological solutions to ensure customer communication and distributed generation facilities in an optimal way. Energy management in microgrids refers to the information and control system that provides the necessary functionality to guarantee that the generating and distribution systems produce energy at the lowest expenses. This study analyzes the various optimization objectives, constraints, problem-solving techniques, and simulation tools used for connected and freestanding microgrids. It reviews the literature on energy control in microgrids powered by sustainable energy. Energy storage technology is also viewed as an intriguing alternative to managing the intermittent nature of renewable energy because of its advanced techniques, increased energy efficiency, and capa... [more]
The “Smart” Concept from an Electrical Sustainability Viewpoint
Ignacio Llanez-Caballero, Luis Ibarra, Angel Peña-Quintal, Glendy Catzín-Contreras, Pedro Ponce, Arturo Molina, Ricardo Ramirez-Mendoza
April 17, 2023 (v1)
Keywords: smart buildings, smart cities, smart devices, smart grids, smart houses
Nowadays, there are many technological-intensive applications that claim to be “smart”. From smartphones to the smart grid, people relate the word smart with technical novelty, automation, enabled communication, and service integration. There is indeed a gap between those smart technologies and their intended “intelligence”; this has arisen an indirect debate between works focusing on automation and mechatronics design and others pursuing a conceptual approach based on fulfilling determinate objectives. One last approach relates the said smartness to deep learning methodologies. In this work, it is attempted to explore both perspectives by providing an overview of recent works around energy usage toward smart cities and the smart grid, pointing out the main conceptual pillars upon which both approaches stand. Certainly, there are enabling technologies supporting the smart concept overall; thus, this work addresses them to characterize “smart” not from technological or conceptual one-si... [more]
A Hybrid Feature Pyramid CNN-LSTM Model with Seasonal Inflection Month Correction for Medium- and Long-Term Power Load Forecasting
Zizhen Cheng, Li Wang, Yumeng Yang
April 17, 2023 (v1)
Keywords: causal dilated convolution, feature pyramid CNN-LSTM hybrid neural network, medium- and long-term load forecasting
Accurate medium- and long-term power load forecasting is of great significance for the scientific planning and safe operation of power systems. Monthly power load has multiscale time series correlation and seasonality. The existing models face the problems of insufficient feature extraction and a large volume of prediction models constructed according to seasons. Therefore, a hybrid feature pyramid CNN-LSTM model with seasonal inflection month correction for medium- and long-term power load forecasting is proposed. The model is constructed based on linear and nonlinear combination forecasting. With the aim to address the insufficient extraction of multiscale temporal correlation in load, a time series feature pyramid structure based on causal dilated convolution is proposed, and the accuracy of the model is improved by feature extraction and fusion of different scales. For the problem that the model volume of seasonal prediction is too large, a seasonal inflection monthly load correcti... [more]
A Robust Participation in the Load Following Ancillary Service and Energy Markets for a Virtual Power Plant in Western Australia
Behnaz Behi, Philip Jennings, Ali Arefi, Ali Azizivahed, Almantas Pivrikas, S. M. Muyeen, Arian Gorjy
April 17, 2023 (v1)
Keywords: ancillary service, bidding strategy, customer engagement, energy market, gamification, internal rate of return, load-following ancillary service, payback period, virtual power plants, wholesale electricity market
Virtual power plants (VPPs) are an effective platform for attracting private investment and customer engagement to speed up the integration of green renewable resources. In this paper, a robust bidding strategy to participate in both energy and ancillary service markets in the wholesale electricity market is proposed for a realistic VPP in Western Australia. The strategy is accurate and fast, so the VPP can bid in a very short time period. To engage customers in the demand management schemes of the VPP, the gamified approach is utilized to make the exercise enjoyable while not compromising their comfort levels. The modelling of revenue, expenses, and profit for the load-following ancillary service (LFAS) is provided, and the effective bidding strategy is developed. The simulation results show a significant improvement in the financial indicators of the VPP when participating in both the LFAS and energy markets. The payback period can be improved by 3 years to the payback period of 6 ye... [more]
Energy Harvesting Technologies and Devices from Vehicular Transit and Natural Sources on Roads for a Sustainable Transport: State-of-the-Art Analysis and Commercial Solutions
Roberto De Fazio, Mariangela De Giorgi, Donato Cafagna, Carolina Del-Valle-Soto, Paolo Visconti
April 17, 2023 (v1)
Keywords: energy harvesting, piezoelectric transducers, solar roadways, vehicle transit, vibrations
The roads we travel daily are exposed to several energy sources (mechanical load, solar radiation, heat, air movement, etc.), which can be exploited to make common systems and apparatus for roadways (i.e., lighting, video surveillance, and traffic monitoring systems) energetically autonomous. For decades, research groups have developed many technologies able to scavenge energy from the said sources related to roadways: electromagnetism, piezoelectric and triboelectric harvesters for the cars’ stress and vibrations, photovoltaic modules for sunlight, thermoelectric solutions and pyroelectric materials for heat and wind turbines optimized for low-speed winds, such as the ones produced by moving vehicles. Thus, this paper explores the existing technologies for scavenging energy from sources available on roadways, both natural and related to vehicular transit. At first, to contextualize them within the application scenario, the available energy sources and transduction mechanisms were iden... [more]
Distributed Energy Management for Networked Microgrids with Hardware-in-the-Loop Validation
Guodong Liu, Maximiliano F. Ferrari, Thomas B. Ollis, Aditya Sundararajan, Mohammed Olama, Yang Chen
April 17, 2023 (v1)
Keywords: alternating direction method of multipliers (ADMM), distributed optimization, energy management, hardware-in-loop (HIL), networked microgrids
For the cooperative operation of networked microgrids, a distributed energy management considering network operational objectives and constraints is proposed in this work. Considering various ownership and privacy requirements of microgrids, utility directly interfaced distributed energy resources (DERs) and demand response, a distributed optimization is proposed for obtaining optimal network operational objectives with constraints satisfied through iteratively updated price signals. The alternating direction method of multipliers (ADMM) algorithm is utilized to solve the formulated distributed optimization. The proposed distributed energy management provides microgrids, utility-directly interfaced DERs and responsive demands the opportunity of contributing to better network operational objectives while preserving their privacy and autonomy. Results of numerical simulation using a networked microgrids system consisting of several microgrids, utility directly interfaced DERs and respons... [more]
Evaluation of Electric Power Quality in the Ship-Integrated Electrical Power System with a Main DC Bus and Power Semiconductor Electric Drives as Part of the Electric Propulsion Complex
Dmytro Zhuk, Oleksandr Zhuk, Maksym Kozlov, Serhii Stepenko
April 17, 2023 (v1)
Keywords: calculation methodology, electric power system, electricity, losses, model, parasitic capacitance, quality
The relevance of the work is connected to the energy efficiency of specialized vessels of the technical fleet. The purpose of the study was to determine and evaluate the power quality indicators associated with the non-sinusoidal shape of the voltage and current curves in the electrical power system of the marine platform support vessel, which contains powerful semiconductor propulsion electric drives, taking into account the inherent and parasitic parameters of the power three-phase cable lines. A simplified one-line diagram of an electric power system with a DC main bus was the object of the study, which was compiled as a result of the analysis of analog systems typical for the indicated type of vessels. The phenomenon of voltage and current distortion caused by the presence of higher harmonics generated by power semiconductor converters in a three-phase ship network was the subject of the research. For the experimental study of the quality of electric power according to the simplifi... [more]
AC Microgrid Protection System Design Challenges—A Practical Experience
Sarat Chandra Vegunta, Michael J. Higginson, Yashar E. Kenarangui, George Tsai Li, David W. Zabel, Mohammad Tasdighi, Azadeh Shadman
April 14, 2023 (v1)
Keywords: distribution energy resources, microgrids, power distribution, power system protection
Alternating current (AC) microgrids are the next step in the evolution of the electricity distribution systems. They can operate in a grid-tied or island mode. Depending on the services they are designed to offer, their grid-tied or island modes could have several sub-operational states and or topological configurations. Short-circuit current levels and protection requirements between different microgrid modes and configurations can vary significantly. Designing a microgrid’s protection system, therefore, requires a thorough understanding of all microgrid operational modes, configurations, transitional states, and how transitions between those modes are managed. As part of the microgrid protection design, speed and reliability of information flow between the microprocessor-based relays and the microgrid controller, including during microgrid failure modes, must be considered. Furthermore, utility protection practices and customer requirements are not always inclusive of the protection... [more]
Improving Power Quality by a Four-Wire Shunt Active Power Filter: A Case Study
Mihaela Popescu, Alexandru Bitoleanu, Mihaita Linca, Constantin Vlad Suru
April 14, 2023 (v1)
Keywords: distortion power, power quality, shunt active power filter, three-phase four-wire system, unbalanced load
This paper presents the use of a three-phase four-wire shunt active power filter to improve the power quality in the Department of Industrial Electronics of a large enterprise from Romania. The specificity is given by the predominant existence of single-phase consumers (such as personal computers, printers, lighting and AC equipment). In order to identify the power quality indicators and ways to improve them, an A-class analyzer was used to record the electrical quantities and energy parameters in the point of common coupling (PCC) with the nonlinear loads for 27 h. The analysis shows that, in order to improve the power quality in PCC, three goals must be achieved: the compensation of the distortion power, the compensation of the reactive power and the compensation of the load unbalance. By using the conceived three-leg shunt active power filter, controlled through the indirect current control method in an original variant, the power quality at the supply side is very much improved. In... [more]
Showing records 245 to 269 of 1388. [First] Page: 1 7 8 9 10 11 12 13 14 15 Last
[Show All Subjects]