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Energies ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 592
Author(s):  
Mohammadjavad Mobarra ◽  
Miloud Rezkallah ◽  
Adrian Ilinca

Diesel generators (DGs) are set to work as a backup during power outages or support the load in remote areas not connected to the national grid. These DGs are working at a constant speed to produce reliable AC power, while electrical energy demand fluctuates according to instantaneous needs. High electric loads occur only for a few hours a day in remote areas, resulting in oversizing DGs. During a low load operation, DGs face poor fuel efficiency and condensation of fuel residues on the walls of engine cylinders that increase friction and premature wear. One solution to increase combustion efficiency at low electric loads is to reduce diesel engine (DE) speed to its ideal regime according to the mechanical torque required by the electrical generator. Therefore, Variable Speed Diesel Generators (VSDGs) allow the operation of the diesel engine at an optimal speed according to the electrical load but require additional electrical equipment and control to maintain the power output to electrical standards. Variable speed technology has shown a significant reduction of up to 40% fuel consumption, resulting in low GHG emissions and operating costs compared to a conventional diesel generator. This technology also eliminates engine idle time during a low load regime to have a longer engine lifetime. The main objective of this survey paper is to present the state of the art of the VSDG technologies and compare their performance in terms of fuel savings, increased engine lifetime, and reduced greenhouse gases (GHG) emissions. Various concepts and the latest VSDG technologies have been evaluated in this paper based on their performance appraisal and degree of innovation.


Author(s):  
Ю.А. Клименко ◽  
А.П. Преображенский

В статье рассматривается решение задачи моделирования процесса управления электрическими нагрузками для повышения качественных показателей электрической энергии в распределительных электрических сетях 0,4 кВ на основе использования адаптивной системы управления электрическими нагрузками. Проведен анализ существующих методов снижения неравномерности распределения мощностей. Алгоритм процесса управления электрическими нагрузками в распределительных электрических сетях, алгоритмы анализа распределения мощностей и напряжений по фазам сети, а также алгоритм устранения отклонений напряжения, которые могут быть использованы при разработке электрооборудования. для обеспечения необходимого качества электроэнергии. The paper considers the solution of the problem of modeling the process of controlling electrical loads to improve the quality parameters of electrical energy in distribution electrical networks of 0.4 kV based on the use of an adaptive system for controlling electrical loads. The analysis of existing methods of reducing the uneven distribution of capacities is carried out. An algorithm for the process of controlling electrical loads in distribution electrical networks, algorithms for analyzing the distribution of powers and voltages over the phases of the network, as well as an algorithm for eliminating voltage deviations, which can be used in the development of electrical equipment to ensure the required quality of electricity, have been developed.


Energies ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 104
Author(s):  
Henning Schlachter ◽  
Stefan Geißendörfer ◽  
Karsten von Maydell ◽  
Carsten Agert

Due to the increasing penetration of renewable energies in lower voltage level, there is a need to develop new control strategies to stabilize the grid voltage. For this, an approach using deep learning to recognize electric loads in voltage profiles is presented. This is based on the idea to classify loads in the local grid environment of an inverter’s grid connection point to provide information for adaptive control strategies. The proposed concept uses power profiles to systematically generate training data. During hyper-parameter optimizations, multi-layer perceptron (MLP) and convolutional neural networks (CNN) are trained, validated, and evaluated to determine the best task configurations. The approach is demonstrated on the example recognition of two electric vehicles. Finally, the influence of the distance in a test grid from the transformer and the active load to the measurement point, respectively, onto the recognition accuracy is investigated. A larger distance between the inverter and the transformer improved the recognition, while a larger distance between the inverter and active loads decreased the accuracy. The developed concept shows promising results in the simulation environment for adaptive voltage control.


2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Mohsen Keykha ◽  
T. Fanaei Sheikholeslami

Abstract The Triboelectric nanogenerators (TENGs) are Fabricated by contact between two surfaces of different materials and convert of electric loads between them. In such structures, the two contacting layers should be radically different in terms of their electric property so that one of the layers could induce positive electrical charge while the other induces a negative charge. The application of force on and friction between the two layers induce positive and negative charges. Through the electrodes in external load, the electrical charges flow as electric current. In the present study, TEGN structures fabricated of polyethylene terephthalate polymers (PET) act as electron acceptor while Polyamide (KAPTON) and polydimethylsiloxane (PDMS) act as electron donator. The resulting outputs are compared consequently. Considering the fact that the two materials are relatively identical in terms of electron donation as they are in contact with PET, the generators fabricated of KAPTON could generate 400% more power under identical conditions. Therefore, one may conclude that KAPTON could be more suitable for development of self-power system as they are more available and more environmentally compatible.


Electronics ◽  
2021 ◽  
Vol 10 (24) ◽  
pp. 3136
Author(s):  
Li-Ning Xing ◽  
Hong-Long Xu ◽  
Armin Kardan Sani ◽  
Md. Alamgir Hossain ◽  
S. M. Muyeen

Optimal sizing of hybrid energy systems has been considerably investigated in previous studies. Nevertheless, most studies only focused on providing AC electric loads by renewable energy sources (RESs) and energy storage systems (ESSs). In this paper, a hybrid energy system, including photovoltaic (PV) system, ESS, fuel cell (FC), natural gas (NG) boiler, thermal load controller (TLC), and converter is optimized for supplying different load demands. Three scenarios are introduced to investigate the feasibility of the energy system. Environmental aspects of each system are analyzed, as there are NG-consuming sources in the system structure. A sensitivity analysis is conducted on the influential parameters of the system, such as inflation rate and interest rate. Simulation results show that the proposed hybrid energy system is economically and technically feasible. The net present cost (NPC) and cost of energy (COE) of the system are obtained at $230,223 and $0.0409, respectively. The results indicate that the TLC plays a key role in the optimal operation of the PV system and the reduction in greenhouse gas emission productions.


2021 ◽  
Vol 11 (22) ◽  
pp. 10608
Author(s):  
Johnathan Burgess ◽  
Timothy Runnels ◽  
Joshua Johnsen ◽  
Joshua Drake ◽  
Kurt Rouser

This article compares direct turbine throttle control and active turbine throttle control for a turboelectric system; the featured turboprop is rated for 7 kW of shaft output power. The powerplant is intended for applications in unmanned aerial systems and requires a control system to produce different amounts of power for varying mission legs. The most straightforward control scheme explored is direct turbine control, which is characterized by the pilot controlling the throttle of the turbine engine. In contrast, active control is characterized by the turbine reacting to the power demanded by the electric motors or battery recharge cycle. The transient response to electric loads of a small-scale turboelectric system is essential in identifying and characterizing such a system’s safe operational parameters. This paper directly compares the turbogenerator’s transient behavior to varying electric loads and categorizes its dynamic response. A proportional, integral, and derivative (PID) control algorithm was utilized as an active throttle controller through a microcontroller with battery power augmentation for the turboelectric system. This controller manages the turbine’s throttle reactions in response to any electric load when applied or altered. By comparing the system’s response with and without the controller, the authors provide a method to safely minimize the response time of the active throttle controller for use in the real-world environment of unmanned aircraft.


Energies ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5863
Author(s):  
Arthur Santos ◽  
Gerald Duggan ◽  
Stephen Frank ◽  
Daniel Gerber ◽  
Daniel Zimmerle

Advances in power electronics and their use in Miscellaneous Electric Loads (MELs) in buildings have resulted in increased interest in using low-voltage direct current (DC) power distribution as a replacement for the standard alternating current (AC) power distribution in buildings. Both systems require an endpoint converter to convert the distribution system voltage to the MELs voltage requirements. This study focused on the efficiency of these endpoint converters by testing pairs of AC/DC and DC/DC power converters powering the same load profile. In contrast to prior studies, which estimated losses based on data sheet efficiency and rated loads, in this study, we used part load data derived from real-world time-series load measurements of MELs and experimentally characterized efficiency curves for all converters. The measurements performed for this study showed no systematic efficiency advantage for commercially available DC/DC endpoint converters relative to comparable, commercially available AC/DC endpoint converters. For the eight appliances analyzed with the pair of converters tested, in 50%, the weighted energy efficiency of the DC/DC converter was higher, while, for the other 50%, the AC/DC converter was. Additionally, the measurements indicated that the common assumption of using either data sheet efficiency values or efficiency at full load may result in substantial mis-estimates of the system efficiency.


Author(s):  
Rahul Kumar Bhardwaj

Microgrids are the small version of power system which grants us the integration of distributed generation resources to insure the facilities to the remotely located electric loads as well as have so many advantages over traditional power system like reduced transmission loss, green energy solution and proper use of renewable energy resources. However the resilience offered by microgrid is inconvenient if it is not be able to protect properly in case of any disturbance occurs which is very common in microgrid due to load dynamics. Protective devices used in traditional power grid cannot actually protect microgrid due to variable loads and different fault levels at grid connected modes and islanded modes. The available research about this concern has not been very successful, therefore options like distance, directional over current and differential relay remains effective protection scheme from present standard. Even though these relays are very useful in power system but their effectiveness for microgrid is yet to be analyzed. This paper is presenting the MATLAB simulation based analysis for differential relay type adaptive protection system by taking a complex microgrid model and generating various fault and generation capacities and analyzing it. In this paper different scenarios has been discussed where differential relay seems to be better than distance and directional over current relay protection scheme.


Author(s):  
Yu. I. Soluyanov ◽  
A. R. Akhmetshin ◽  
V. I. Soluyanov

THE PURPOSE. To determine the composition of electricity consumers in apartment buildings. To analyze the power consumption of organizations located on the first two floors of apartment buildings. To justify the need to update the standards for electrical loads for public premises built into residential buildings. METHODS. Information on electricity consumption was received by automated electricity metering system from smart meters installed directly at consumers. To achieve this goal, statistical methods for analyzing energy consumption were used. RESULTS. The article describes the relevance of the topic, provides a rationale for adjusting the normative values of specific electrical loads for public premises built into residential buildings. The percentage of consumer groups is shown on the example of several apartment buildings. The annual specific average monthly graphs of electricity consumption are presented: shops, offices, pharmacies, restaurants. CONCLUSION. In an effort to increase the level of comfort, developers are interested in developing the infrastructure of the facilities, mainly for this, they use ground and first floors, in which retail and office areas are most often located. Research by the Roselectromontazh Association has shown that to determine the electrical load of non-residential commercial premises, one has to use one averaged value due to the constant change in the purpose of premises and the complexity of determining the occupied area.


Author(s):  
Yu. I. Soluyanov ◽  
A. R. Akhmetshin ◽  
V. I. Soluyanov

THE PURPOSE. To determine the composition of electricity consumers in apartment buildings. To analyze the power consumption of organizations located on the first two floors of apartment buildings. To justify the need to update the standards for electrical loads for public premises built into residential buildings. METHODS. Information on electricity consumption was received by automated electricity metering system from smart meters installed directly at consumers. To achieve this goal, statistical methods for analyzing energy consumption were used. RESULTS. The article describes the relevance of the topic, provides a rationale for adjusting the normative values of specific electrical loads for public premises built into residential buildings. The percentage of consumer groups is shown on the example of several apartment buildings. The annual specific average monthly graphs of electricity consumption are presented: shops, offices, pharmacies, restaurants. CONCLUSION. In an effort to increase the level of comfort, developers are interested in developing the infrastructure of the facilities, mainly for this, they use ground and first floors, in which retail and office areas are most often located. Research by the Roselectromontazh Association has shown that to determine the electrical load of non-residential commercial premises, one has to use one averaged value due to the constant change in the purpose of premises and the complexity of determining the occupied area.


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