Large Electrical Loads Research Articles

Cost minimization of a hybrid PV-to-methanol plant through participation in reserve markets: A Danish case study

In efforts to combat carbon emissions in challenging sectors like heavy industry and shipping, Power-to-X (PtX) technology emerges as a promising solution. PtX involves converting renewable energy into hydrogen via water electrolysis and further processing it into eco-friendly fuels like methanol, ammonia, or kerosene. Denmark has seen a rise in plans for integrating large-scale PtX projects, which will introduce large electrical loads to its power system.To optimize the cost-effectiveness of PtX-based fuel production, a proposal suggests leveraging PtX plants’ inherent flexibility to provide frequency reserves to the electrical grid. The study centers on a real-life hybrid renewable energy system (HRES) dedicated to methanol production in Denmark.Analyzing the HRES technology and current reserve markets reveals that the HRES qualifies for frequency reserve provision certification, encompassing FCR, aFRR, and mFRR, by the transmission system operator. Through participation in the reserve market, the HRES can generate added revenue, resulting in substantial reductions of 12% and 30% in the levelised cost of methanol for 2020 and 2021 operational expenditure outcomes, respectively.The study illustrates significant cost reductions achievable through engagement in reserve markets, and these reductions may escalate further with increased market prices and volatility. Participating in frequency reserve capacity markets not only facilitates overall cost reduction but also serves as an insurance policy against unpredictable energy market fluctuations. This approach presents a promising trajectory to promote PtX technology adoption and nurture sustainable energy practices in challenging sectors.

Impact of turbine technology on wind energy potential and CO2 emission reduction under different wind resource conditions in China

Comprehensive knowledge about wind energy potential is critical for decision-making to achieve carbon neutrality and shape future energy pathways. Wind turbine technology advances (e.g., higher hub-heights, larger rotor diameters and rated power) can better support wind energy harvesting and alter wind energy potential. This study established an integrated model to evaluate the impact of wind turbine technology advances on onshore wind energy potentials under different wind resource conditions by using China as a case study. We found that technological advances of wind turbine can significantly impact wind energy potential. Compared with land-based 1.5-MW turbines, the onshore wind energy potential using newer generation turbines (land-based 2.5-MW turbines) would increase by 43% to 14.8 PWh (i.e., 2.0 times the electricity consumption of China in 2020). Importantly, advances in wind turbine technology can significantly increase capacity factor in poor wind resource regions, and thus enable economically viable generation in more areas. This can significantly increase wind energy potential in poor wind resource regions with large electrical load (e.g., Central, South and East China). Moreover, in contrast to the wind production of 0.46 PWh in 2020, China's wind energy potential is projected to hit 20.1 PWh by 2030 under the assumption of developed turbine technology in line with the trends of the past decade. The corresponding potential CO2 emission reduction would range from 12.6 Gt in 2020 to 21.7 Gt in 2030. These values are 1.3 and 2.2 times higher than China's CO2 emissions in 2020, respectively. To enhance wind energy contribution toward China's carbon neutrality goal, we recommend that the conversion of wind turbines to be accelerated, especially in poor wind resource regions with large electrical load.

CURRENT STATE AND PROSPECTS OF IMPROVING THE LIGHTING EQUIPMENT OF AIRCRAFTS

The development of aviation technology is directly related to technological progress. Taking this into account, the question of switching to modern light sources on aircraft arises. Lighting equipment plays an important role in ensuring the operation of aircraft and flight safety, especially at night. Among the elements of aircraft’s electrical equipment, lighting equipment represents a fairly large electrical load (5.20 % of the total power of consumers).Today, incandescent lamps are most often used in aircraft lighting systems, in which an incandescent thread (a refractory conductor, a spiral made of tungsten alloy), located in a glass vessel with a vacuum or filled with an inert gas, is heated to a high temperature (luminosity temperature) due to the flow of electric current through this thread.
 Recently, reliable and energy-efficient Light Emitting Diode (LED) light sources have been widely implemented in lighting systems for various purposes. Light diodes have now become light sources that are produced on an industrial scale for a variety of needs. LEDs are one of the key devices in today’s technological society. Unlike many other light sources, LEDs can convert electrical energy into light with an efficiency close to unity. It is expected that the role of LEDs will only grow and in the future they will become the main source of light.
 Consequently, the light sources currently used on aircraft of the Armed Forces of Ukraine are outdated and do not correspond to the level of accumulated scientific and technical potential. Therefore, research aimed at introducing LED light technologies to the lighting equipment of aircraft is relevant.
 The article considers the typical structure and main characteristics of aircraft’s lighting equipment of the Armed Forces of Ukraine. The stages of development of aircraft lighting equipment, the main types of existing lighting sources and their features are considered. It is noted that the development of lighting technology and the successful introduction of LEDs into lighting technology for various purposes allow us to consider the possibility of using them as the main light source on aircraft in order to improve operational characteristics. The relevance of conducting research aimed at improving the lighting equipment of aircraft is substantiated.

A Generalized Passivity-Based Stability Criterion for Assessing Large Signal Stability of Interconnected DC Power Systems

With the growing need to support large dynamic electric loads in microgrid environments, there has been a necessary push toward highly regulated dc distribution through power electronics. Unfortunately, these systems are nonlinear by nature and provide potentially destabilizing behavior at their source interfaces. To complicate matters further, many systems are built from independently designed subcomponents with little information shared between designs. It is, therefore, necessary to have stability-driven design requirements for each subsystem to enforce stable dynamics upon system integration. Traditional techniques are currently limited to either overly conservative large signal small-gain methods or small signal transfer function approaches that are unreliable for assuring large signal stability. This article proposes a generalized passivity-based stability criterion that conservatively estimates the domain of stability for an integrated nonlinear system. Through passivity partitioning and uniquely driven domain of passivity estimation techniques, this methodology provides interface conditions that certify stability while only requiring a reduced subset of knowledge of each connected subsystem <bold xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">.</b>

The jumping dielectric breakdown behavior induced by crack propagation in ferroelectric materials: A phase field study

Ferroelectric materials often experience fracture and dielectric breakdown under large mechanical and/or electrical loads. These two failure behaviors can affect each other and may lead to new phenomena. This study predicts a new type of jumping dielectric breakdown during crack propagation in ferroelectric materials using a phase field model involving multiple order parameters. The driving forces for the evolution of polarization, fracture, and dielectric breakdown were analysed based on the concept of configurational forces. The jumping dielectric breakdown was attributed to the competition between crack propagation and breakdown initiation at the moving crack tip. The breakdown pattern is related to the polarization domain structure and is significantly influenced by the applied electric field and crack boundary conditions. Furthermore, the jumping breakdown associated with possible mechanical degradation of the material can change the driving and resistance forces for crack propagation. This study introduces a novel dielectric breakdown behavior during crack propagation and provides new insights into the coupling failure of ferroelectric materials.

Phase field modeling of coupling evolution of fracture and dielectric breakdown in ferroelectric materials

Ferroelectric materials have attracted increasing attention due to their distinguished electromechanical coupling properties. Fracture and dielectric breakdown are two main failure behaviours of ferroelectric materials, which may occur simultaneously under large mechanical and electrical loads. Understanding the coupling evolution of fracture and dielectric breakdown is crucial for the application of ferroelectric materials under complex electromechanical environments. In the present study, a phase field model with multiple order parameters is developed to investigate the coupling evolution behaviours of fracture and dielectric breakdown of ferroelectric materials subjected to the mechanical and electrical loadings. In the phase field model, coupled electromechanical degradation functions are proposed to model the interface boundary conditions of fracture and dielectric breakdown. Generalized configurational forces of fracture and dielectric breakdown are obtained from the phase field model to analyse the driving forces for the evolution of fracture and dielectric breakdown. The interaction between fracture and dielectric breakdown is predicted by using the phase field model with a set of interface boundary conditions. The simulation results show that dielectric breakdown occurs at impermeable crack tips due to the concentrated electric field, while the stress distribution around the crack tip and the driving force of crack propagation are influenced by dielectric breakdown. The attraction of crack to electrical treeing path and the deflection of electrical treeing to crack path are predicted during the coupling evolution of fracture and dielectric breakdown. The results of this work provide an in-depth insight into the electromechanical coupling failure of fracture and breakdown of ferroelectric materials. The developed model framework can be employed to investigate more complex electromechanical coupling failures of dielectric, piezoelectric and ferroelectric materials and structures.

Low voltage customer phase identification methods based on smart meter data

The increased deployment of distributed energy generation and the integration of new, large electric loads such as electric vehicles and heat pumps challenge the correct and reliable operation of low voltage distribution systems. To tackle potential problems, active management solutions are proposed in the literature, which require distribution system models that include the phase connectivity of all the consumers in the network. However, information on the phase connectivity is in practice often unavailable. In this work, several voltage and power measurement-based phase identification methods from the literature are implemented. A consistent comparison of the methods is made across different smart meter accuracy classes and smart meter penetration levels using publicly available data. Furthermore, a novel method is proposed that makes use of ensemble learning and that can combine data from different measurement campaigns. The results indicate that generally better results are obtained with voltage data compared to power data from smart meters of the same accuracy class. If power data is available too, the novel ensemble method can improve the accuracy of the phase identification obtained from voltage data alone.

Automatic Power Factor Detector and Corrector using Arduino Mini Pro

In recent years, the power quality of the ac system has become great concern due to the rapidly increased numbers of electronic equipment, power electronics and high voltage power system. Most of the commercial and industrial installation in the country has large electrical loads which are severally inductive in nature causing lagging power factor which gives heavy penalties to consumer by electricity board. This situation is taken care by PFC. Power factor correction is the capacity of absorbing the reactive power produced by a load. In case of fixed loads, this can be done manually by switching of capacitors, however in case of rapidly varying and scattered loads it becomes difficult to maintain a high power factor by manually switching on/off the capacitors in proportion to variation of load within an installation. This drawback is overcome by using an APFC panel.

Learning Large Electrical Loads via Flexible Contracts With Commitment

Large electricity customers (e.g., large data centers) can exhibit huge and variable electricity demands, which poses significant challenges for the electricity suppliers to plan for sufficient capacity. Thus, it is desirable to design incentive and coordination mechanisms between the customers and the supplier to lower the capacity cost. This paper proposes a novel scheme based on flexible contracts. Unlike existing demand-side management schemes in the literature, a flexible contract leads to information revelation. That is, a customer committing to a flexible contract reveals valuable information about its future demand to the supplier. Such information revelation allows the customers and the supplier to share the risk of future demand uncertainty. On the other hand, the customer will still retain its autonomy in operation. We address two key challenges for the design of optimal flexible contracts: i) the contract design is a non-convex optimization problem and is intractable for a large number of customer types, and ii) the design should be robust to unexpected or adverse responses of the customers, i.e., a customer facing more than one contract yielding the same benefit may choose the contract less favorable to the supplier. We address these challenges by proposing sub-optimal contracts of low computational complexity that can achieve a provable fraction of the performance gain under the global optimum.

Leveraging thewater‐energynexus to derive benefits for the electric grid throughdemand‐sidemanagement in the water supply and wastewater sectors

AbstractLeveraging the potential flexibility of large electrical loads has become an attractive option for maintaining grid reliability, especially in electric grids with high penetrations of variable renewable energy. The water sector is a particularly attractive option for demand‐side flexibility due to its vast water storage infrastructure, large interruptible pumping loads, and energy generation opportunities. Shifting the timing of water supply and wastewater utility operations can reduce peak load and temporally align energy‐consuming activities with periods of cheap electricity prices and/or high renewable energy generation. This paper presents a general overview of demand‐side management strategies in water and wastewater systems, focusing primarily on demand‐response measures. We find that while there is consensus in the literature about the potential for water systems to provide flexible demand‐side management services, there is a need for developing comprehensive water‐energy models to examine the value of load management as a source of revenue for water utilities and as a source of flexibility for the electric grid. More experimental studies and simulation efforts are also needed to address the technical complexities and water quality concerns associated with interrupting water and wastewater utility operations.This article is categorized under:Engineering Water &gt; Sustainable Engineering of WaterEngineering Water &gt; Planning Water

Feasibility Study of Micro Hydropower Plants in High-Rise Buildings in Indonesia By Utilizing A Working Scheme for AC Condenser Water Pumps (Ventilation & Air Conditioning System)

In Indonesia the number of high-rise buildings above 150 m tends to increase, according to CTBUH (Council on tall building and urban habitat) in 2018 there are 85 buildings and those that are under construction are 26 buildings, Super tall buildings with a height above 300 meters are 4 buildings and proposed mega tall building with a height of more than 600 meters is 1 building. All these buildings have very large electrical loads. The percentage of electricity consumption in the building that is the object of research is 30-50% coming from the Ventilation & Air Condition (VAC) system, 20% - 30% lighting systems, 10% computers and the rest from other utilities. Several papers and journals discussing the simulation or feasibility study of micro-hydropower plants in high-rise buildings have not yet been discussed how to utilized kinetic energy from the working scheme of the water condenser pump in the VAC system. in general, the existing papers discuss how to utilized gravity potential energy through the working scheme of the building’s clean water tank which is on the roof (rooftop) when distributing water which is not optimal because of the flow of water from the clean water system is not continuous or steady-state. Research Object by taking a case study of a high-rise building in Jakarta with a height of 157 meters. The data was taken from the report on utility use for the 2018 period in the building. From the simulation, the potential of water flow rate (Q) is 0.499 m3 / sec and the electrical power that can be generated (P) is 733.83 kW and this is a Micro-hydro Power Generation category. Economic analysis for building energy savings of Rp. 541,765,714.29 / month and finally roughly Return on Investment (ROI) can be achieved in 3 years and 6 months.

Nonlinear bilateral caloric–electromechanical couplings in polycrystalline ferroelectrics

AbstractThis research is about irreversible domain wall motion leading to a temperature change of the material. The materials are mostly subjected to high frequencies and large electrical loads, which is why insufficient heat dissipation can lead to undesirable temperature developments, so–called self heating. Predictions concerning polycrystalline material behavior are made by the condensed method.

Non-overlapping moving compressive measurement algorithm for electrical energy estimation of distorted m-sequence dynamic test signal

The complex random characteristics in smart grid lead to inaccuracy of smart electricity metering. This is caused by the power filter and energy accumulation algorithm under dynamic signal conditions. By analyzing the typical intrinsic characteristics of large power electrical loads, this paper proposes a distorted m-sequence dynamic test (DmDT) signal model to reflect the characteristics and summarizes the parameter set that relates to the characteristics. In addition, based on the compressive measurement (CM) theory, a novel non-overlapping moving compressive measurement (NOLM-CM) algorithm is proposed to accurately estimate electrical energy. The performance of the non-overlapping moving compressive measurement (NOLM-CM) algorithm is tested under representative distorted dynamic random conditions. Simulation and experimental results indicate that the non-overlapping moving compressive measurement (NOLM-CM) algorithm achieves accurate estimation of electrical energy. Furthermore, the comparisons with five popular window-based estimation algorithms by simulations verify the higher performance of the non-overlapping moving compressive measurement (NOLM-CM) algorithm.

Large Signal Modeling Method for AC/DC Independent Power System in dq-Coordinates

Large signal stability means that a system can be a transition to a new stable state without losing synchronism after a large disturbance. The large signal stability problem brought by large capacity electrical loads in ac/dc independent power system is prominent, which seriously affects the dynamic security of the system. In view of modeling characteristics of ac/dc system, a generalized state space average large signal modeling method for the ac/dc independent power system in dq-coordinates is proposed. A large signal model of the ac/dc independent power system is constructed, which includes generators, inverter units, rectifying units, and dc/dc converters. The simulation results indicate that the large signal model constructed in this paper can accurately reflect the dynamic characteristics of the system under large disturbances, such as startup and sudden change in load, which is helpful to understand and improve the dynamic performance of the system under large disturbance. Furthermore, with feasibility and effectiveness, the large signal model provides convenience and possibility for the theoretical analysis of large signal stability of ac/dc independent power systems in the future.

Dynamic Time Warping and FFT: A Data Preprocessing Method for Electrical Load Forecasting

For power suppliers, an important task is to accurately predict the short-term load. Thus many papers have introduced different kinds of artificial intelligent models to improve the prediction accuracy. In recent years, Random Forest Regression (RFR) and Support Vector Machine (SVM) are widely used for this purpose. However, they can not perform well when the sample data set is too noisy or with too few pattern feature. It is usually difficult to tell whether a regression algorithm can accurately predict the future load from the historical data set before trials. Here we demonstrate a method which estimates the similarity between time series by Dynamic Time Warping (DTW) combined with Fast Fourier Transform (FFT). Results show this is a simple and fast method to filter the raw large electrical load data set and improve the learning result before looping through all learning processes.

Frequency dependences of higher-order constants of piezoelectric ceramics

The properties of TBC-3 and PZT-23 piezoelectric ceramics have been studied by the method of loaded three-element complex oscillator. Changes in the higher-order (up to fifth) parameters are considered for large mechanical (0–120 MPa) and electric (0–600 kV/m) loads. Results of studying the longitudinal flexibility s 11 , piezoelectric modulus d 31, and dielectric permittivity e 33 σ are presented within a frequency range of 20–200 kHz, where the frequency dispersion of dielectric as well as piezoelectric and elastic parameters is observed.

Coordinated Model Predictive Control of Aircraft Gas Turbine Engine and Power System

Motivated by the growing need to accommodate large transient thrust and electrical load requests in future more-electric aircraft, a coordinated control strategy for a gas turbine engine, generators, and energy storage is developed. An advanced two-generator configuration, with each generator connected to a shaft of the gas turbine engine, is treated. Model predictive control maximizes system performance and protects this system against constraint violations. The controller design is exploits rate-based linear prediction models. In addition, an auxiliary offset state improves the match between the linear prediction model and the nonlinear system. The auxiliary offset state allows the system to be controlled over the large operating range without requiring multiple linearizations/controllers. The advantages of different energy storages are also compared to complement the two-generator configuration in a more electric aircraft. Primary results indicate that the coordinated model predictive control with an auxiliary offset state yields better performance than other control strategies, and it successfully controls the considered system to satisfy specified requirements over a large operating range. The battery–ultracapacitor pack allows improvement of the overall system performance.

Instantaneous Power Quality Indices Based on Single-Sideband Modulation and Wavelet Packet-Hilbert Transform

Diverse conditions in power systems, such as massive use of nonlinear loads, continuous switching and operation of large electrical loads, and the integration of renewable energies, among others, have adversely affected the power quality (PQ) because they produce undesirable distortions in the waveforms of voltage and current. The conventional way to quantify the PQ is using the PQ indices (PQIs). Yet, the nonstationary properties of voltage and current signals degrade the PQIs estimation whenever classical techniques are used. In this paper, a methodology based on single-sideband modulation method and the Wavelet and Hilbert transforms for the estimation of instantaneous PQIs is proposed. It is shown that the proposal yields better tracking of transitory changes in the voltage/current signals than classical techniques such as the short-time Fourier transform. The PQIs used are the root-mean-square values, frequency, total harmonic distortion, active power, reactive power, apparent power, distortion power, power factor, and total power factor. PQIs performance is validated using synthetic and real signals.

Advanced Methods for Tabulation of Electrical Loads During Special Modes of Marine Vessel Operation

Current shipbuilding standards allow designers to utilize traditional legacy methods for calculation of electrical load totals during typical shipboard evolutions by applying load factors based on percent time in operation. The time has come to consider mandating more intelligent techniques of calculating load totals on vessels with electric propulsion systems. For electric propulsion vessels with special operating profiles, using the traditional methods to attempt to calculate loading on components such as bidirectional zonal power sources/loads simply does not work. For vessels with large variable electric loads, such as electric propulsion, the electric power load analysis should be done using stochastic methods for special modes of operation, such as dynamic positioning, roll-on/roll-off operations, or offshore petroleum discharge mode. This paper will examine the issue from the perspective of a ship designer and will provide examples of how to apply more advanced techniques for performing load analyses on ships with electrical propulsion systems. Proposed changes to classification society rules and other marine standards will be recommended.

Engine-integrated solid oxide fuel cells for efficient electrical power generation on aircraft

This work investigates the use of engine-integrated catalytic partial oxidation (CPOx) reactors and solid oxide fuel cells (SOFCs) to reduce fuel burn in vehicles with large electrical loads like sensor-laden unmanned air vehicles. Thermodynamic models of SOFCs, CPOx reactors, and three gas turbine (GT) engine types (turbojet, combined exhaust turbofan, separate exhaust turbofan) are developed and checked against relevant data and source material. Fuel efficiency is increased by 4% and 8% in the 50 kW and 90 kW separate exhaust turbofan systems respectively at only modest cost in specific power (8% and 13% reductions respectively). Similar results are achieved in other engine types. An additional benefit of hybridization is the ability to provide more electric power (factors of 3 or more in some cases) than generator-based systems before encountering turbine inlet temperature limits. A sensitivity analysis shows that the most important parameters affecting the system's performance are operating voltage, percent fuel oxidation, and SOFC assembly air flows. Taken together, this study shows that it is possible to create a GT-SOFC hybrid where the GT mitigates balance of plant losses and the SOFC raises overall system efficiency. The result is a synergistic system with better overall performance than stand-alone components.