Amount Of Electricity Research Articles

A novel method of quantitative internal short circuit diagnosis based on charging electric quantity in fixed voltage window

Internal short circuit (ISC) is considered as one of the main causes of battery thermal runaway (TR), which has serious potential safety hazards for EVs. However, few electrothermal characteristics bring challenges for battery management system to diagnose ISC in the early stage, especially the accurate quantitative diagnosis. And most of the existing diagnostic methods horizontally compare the characteristics of different batteries, ignoring the impact of battery consistency. Therefore, a novel quantitative ISC diagnosis method based on analyzing the variation of the charging electric quantity in a fixed voltage window of each cell before and after ISC occurrence is proposed, which successfully applies to the diagnosis of traditional laboratory constant-current charging condition and real vehicle step-current charging condition. The fixed voltage window is optimized by the genetic algorithm, and the application conditions of the optimal results are further discussed. The electric quantity growth rate between adjacent cycles is put forward to identify the ISC cell in combination with set threshold value. The proposed method can effectively avoid the consistency issue by longitudinal self-comparison, and the quantitative estimation accuracy is within 6 %.

Equalization method of ‘LiCoxNiyMn1-x-yO2 - LiFePO4’ hybrid battery pack based on charging electric quantity estimation

Battery packs are typically composed of identical cells arranged in series-parallel arrangements, such as LiCoxNiyMn1-x-yO2 battery packs or LiFePO4 battery packs. To fully leverage the advantages of both LiCoxNiyMn1-x-yO2 cells and LiFePO4 cells, manufacturers have proposed an innovative scheme where the two types of cells are connected in series to form a hybrid battery pack. However, the electrical characteristics of the two cells differ significantly. As capacity degradation and self-discharge, the electrical quantity difference between the cells and the configuration of the hybrid battery pack will gradually change. Therefore, a dissipative cell equalization algorithm for the hybrid battery pack based on charging electric quantity estimation is proposed in this paper. The objective of the algorithm is to stabilize the energy output of the hybrid battery pack. We implement the proposed algorithm in simulations, containing a hybrid battery pack model. Dissipation cell equalization algorithm based on charging electric quantity estimation is proved to be effective by comparing the cell electric quantity difference with/without the algorithm. The relationship between cells in the pack with the visualization of equalization is further analyzed. Results demonstrate that closely match the theoretical values achieved through the dissipative equalization strategy after approximately 15 to 20 standard cycles, with a relative difference of no more than 1 % and minimal fluctuations. Therefore, the equalization method can change and recover the electric quantity difference, and achieve the energy stabilization strategy of the hybrid battery pack.

Online Evaluation Method of CVT Internal Insulation Abnormality Based on Self-Supervised Learning

A capacitive voltage transformer (CVT) is one of the electrical quantities measurement devices, and the state of its internal insulation is the key factor for ensuring the accuracy of its measurement of electrical energy. In view of the fact that the traditional real-time evaluation method of a CVT internal insulation anomaly mainly relies on empirical rules and prior knowledge and lacks the ability to independently mine effective features, an online evaluation method of a CVT internal insulation anomaly based on self-supervised learning is proposed. Firstly, an autoencoder is constructed to extract the residual sequence of the CVT secondary voltage and eliminate the influence of primary voltage fluctuation and power system voltage regulation. Without any prior knowledge, the complex dependence of the residual sequences in time and feature dimensions is learned by using a parallel graph attention layer (GATv2). Finally, a joint optimization based on the prediction and reconstruction model is introduced to obtain the abnormal inference score at each timestamp and realize the evaluation of the CVT internal insulation status. Experimental analysis shows that this method can effectively eliminate the influence of primary voltage fluctuation and power system voltage regulation on the online evaluation of the CVT internal insulation status and independently excavate the abnormal characteristics of the CVT secondary voltage to realize real-time monitoring and early warning of the CVT internal insulation status.

Design and fabrication of an IoT-based smart electrical meter for residential energy management

<p>Transparency in electricity measurement and efficient use of electricity are issues of concern to households. Electricity customers want to have confidence in their utility company's electricity meters installed at their houses. This study designs and constructs an internet of things (IoT)-based smart electric meter to measure electricity and remotely control domestic appliances. This device can monitor, calculate electricity bills and remotely control the appliances via the internet; electrical quantities are displayed in real-time on the Blynk app, liquid crystal display (LCD) screen and Google Sheet. The device is also capable of emailing the electricity user. The proposed system is designed and developed based on ESP32, a LCD, a PZEM 004T, four relays and a DC source. The results show that the device works stably and the device’s error is less than 5%. This research makes it possible for users to conveniently monitor their power consumption while enhancing their energy-saving awareness.</p>

ID: 212051 EM Exposure During Non-Invasive Brain Stimulation Applications: Impact of Uncertainties on Treatment Relevant Metrics

Performance and safety of non-invasive brain stimulation (NIBS) techniques (e.g., transcranial electric stimulation (tES) or temporal interference stimulation (TIS)) rely on the precise delivery of stimulation dose (typically electric (E-)field related quantities) to targets. The assessment of uncertainty associated with electromagnetic (EM) dose calculated by finite-element method (FEM) simulations using detailed anatomical human head models to optimize stimulation parameters (e.g., electrode positions, current intensities) and predict safety and performance metrics is therefore essential. We systematically investigated the impact of experimental and modelling sources of uncertainty/variability on tES exposure and exposure-derived quantities (maximum amplitude modulation for TIS, focality of stimulation, etc.).

Prediction of the Physicochemical Properties of Corrosion Inhibitors Using an Total Quantity of Electricity Passed through a Steel–Inhibitor–Electrolyte System

Prediction of the Physicochemical Properties of Corrosion Inhibitors Using an Total Quantity of Electricity Passed through a Steel–Inhibitor–Electrolyte System

Thermal Characterization of Magnetic Components in Still Air

Accurate measurement of losses in magnetic components and the resulting temperature behavior is essential for device characterization and thermal model validation. However, some factors such as the significant phase displacement angle between voltage and current, and the practical challenges of measuring high-frequency electrical quantities need to be considered when choosing excitation equipment, probes, and assembling test setups. This work proposes an experimental and non-invasive procedure for acquiring temperatures of magnetic components in stagnant air with prescribed constant input power. The electrical modeling of the system, the choice of suitable equipment and probes for measuring losses, the structure of the system, pre-test procedures, and other system components are discussed in detail. The validation of the procedure and the experimental setup was performed through testing of E-core and toroidal inductors, altogether with computational fluid dynamics (CFD) simulations for an extended range of power losses. Finally, the results presented an excellent agreement, proving that the proposed methodology is a reliable tool for assessing the thermal behavior of magnetic components.

Reactivity properties of the HOSO and HSO2 isomers in liquid medium: a sequential Monte Carlo/quantum mechanics study.

The rationalization of acid rain formation steps is fundamental for mitigating its effects. It is believed the hydroxysulfinyl radical is an intermediate species for the production of atmospheric sulfuric acid. Two stable configurations HOSO and HSO2 have been reported for such a radical in the gas phase. This work aims at studying these isomers in the aqueous medium. The electrical and reactivity quantities - electronic chemical potential ([Formula: see text]), chemical hardness ([Formula: see text]), and electrophilicity ([Formula: see text]) - are here calculated and compared. Considering first solvation shells (15H2O for HSO2 and 23H2O for HOSO), an increase of 25% in the dipole moment of HSO2 was obtained, while the dipole moment of HOSO decreases in 11%. Both solvated isomers grow softer ([Formula: see text] decreases) contrasted to the gas phase. HOSO and HSO2 are studied through a sequential Monte Carlo/quantum mechanics approach. Lennard-Jones plus the Coulomb potentials were used to represent intermolecular potential interaction in the frame of the DICE package. Molecular structure calculations were performed at CASPT2/aug - cc - pV(T + d)Z level of theory using the MOLPRO suite of programs.

Conformity Assessment in Senegal: Conformity Tests in Laboratories as the Basis for Quality Infrastructure

This work focuses on quality infrastructure in the solar photovoltaic field in Senegal. On the one hand, it deals with the improvement of the quality infrastructure and on the other hand, conformity assessment accompanied by metrology and performance tests on batteries. We felt it was necessary to revisit the concepts of quality infrastructure and conformity assessment. Then in the improvement of this infrastructure metrology tests were carried out on electrical components by performing maximum error calculations to check the conformity on the voltage, the current, frequency and resistance of electrical quantities at a metrology laboratory, the African Laboratory of Metrology and Testing (LAME). We have also carried out compliance tests on batteries with the measuring equipment of the Laboratory for Quality Control of Solar photovoltaic components (LCQS), a laboratory for testing photovoltaic solar components in Senegal. The study of the batteries covers two (2) elements in one cycle with a nominal capacity of 1080Ah. The capacities calculated after the tests performed on the two (2) elements are respectively C1(t)=1223Ah and C2(t)=1318Ah.

Wireless Sensor Transmission System Using Circular Polarized Antenna At 2.4 Ghz Frequency

Sensors in the electronic world are parts that are used to detect changes in the physical or chemical environment. The output from the sensor is converted into an electrical quantity that represents the change in the environment. Sensors are widely used in agriculture, especially to detect changes in the physical or chemical environment related to plant growth, for example: temperature sensors, light sensors, soil moisture sensors, and so on. In agricultural applications that have a large area, the problem of location and distance from the sensor to the control center is a problem in itself. To solve this problem, a sensor system is designed that does not use wired (wireless) connections. In the application of wireless communication systems there is an antenna part which is very important which can affect the rate of sending sensor data. To improve the performance of wireless sensors in sending data, it is necessary to integrate the appropriate antenna with the sensor transceiver system. So this research was conducted to integrate circular polarized antennas with sensors to increase the gain in the transmission. From this integration, measurements are then taken to obtain the value of the radiation pattern, gain and bandwidth. From the resulting measurements, it can be seen that there is an increase in the gain of the wireless sensor transmission using the 2.4 GHz frequency

Statistical Analysis of Cost Reflective Electricity Tariff and Distribution in Nigeria (A Study of Southwest States)

Background: A cost reflective tariff eliminates the need for government subsidies to make up the difference between the prevailing tariff and the actual cost of supply by reflecting the true cost of producing power. However, in order to provide adequate cost reflective tariff, there must be a balanced understanding between the electricity producers and the users in terms of electricity production and supply. It is against this backdrop that this study seeks to investigate the relationship between cost reflective electricity tariff and distribution in Nigeria. Objective: The aim of this study is to empirically investigate the impact of cost reflective tariff on the Nigerian electricity supply industry and to investigate the relationship between cost reflective tariff and electricity distribution using multiple regression analyses. Methods: The data used in this study were secondary data generated and extracted from the World Bank indicators (2020), CBN statistical bulletin (2020) and supplemented with data from Nigerian Electricity Regulatory Commission (2020) that covered the period of the study for the 6 states in southwest. Two models were specified to address the two specific research objectives. The first model sought to test the impact of cost reflective tariff on the Nigeria electricity supply industry using multiple regression analyses and the other to investigate the factors that contributed to the price of electricity determinants in Nigeria. Results: The results showed that the cost of electricity production contributed significantly to the quantity of electricity distributed and the model produced R-square and adjusted R-square values of 91.16% and 87.38%, respectively. Conclusion: The results obtained in this work is useful for electricity producers and government for proper planning.

Energy‐efficient train timetabling for a medium‐speed maglev line considering propulsion and suspension energy consumption

AbstractThis paper addresses the energy‐efficient train timetabling problem for MSM systems, where both propulsion and suspension energy consumption are considered. The timetable design problem is modelled as a bi‐level model for a complete two‐way MSM line. The upper level determines the train departure time at the first station, which makes train operations more convenient for passengers. The lower level uses an empirical description of the train energy consumption as a function of segment running times, and an energy‐efficient timetable optimization model is built. In doing so, all the services in both directions along a certain planning horizon are considered while attending to a known passengers’ demand. Moreover, the convenience of considering energy consumption as part of a broad objective function that includes other relevant costs is pointed out. Then, a unified sequential solution algorithm is developed for an efficient and accurate solution of the bi‐level model. Experiments show that the proposed framework can generate a holographic timetable of energy‐efficient MSM containing multi‐dimensional variables such as time, space, velocity, and electrical quantities.

Research on optimization of power dispatching under the constraint of deviation electricity

In the medium- and long-term electricity market, uncertain power output, and power load will lead to the deviation between the actual generation and the signed medium- and long-term contract electricity. In order to reduce the system deviation balance cost and ensure the balance of power supply and demand, it is necessary to find a suitable dispatch method. First, a monthly electricity decomposition model of thermal power units is proposed in this paper. After that, we propose a power dispatching model under the constraint of deviated electricity quantity to minimize the cost of electricity deviation. The simulation results of numerical examples show that the proposed dispatching model and method can effectively reduce the monthly contract power deviation and the balance cost.

Smart Substation Construction Scheme Based on Micropower Communication and Edge Internet of Things Agent

In recent years, the digital transformation of power grids has become a new trend in the development of power grid enterprises. As a key link, the digitalization and intellectualization of substations have been included in the development plans of major power grid companies. This paper introduces a construction scheme for smart substations. By deploying edge Internet of Things agents, the construction scheme from online monitoring of electrical quantities of electric power equipment to data edge aggregation and data application is realized, which provides an effective solution for the construction of smart substations.

A Time-Domain Analysis Model for Modular-Multilevel-Based Grid-Forming Converters in Isolated Power Supply

The modular multilevel based grid-forming converter (MMGC) is considered to be a viable solution in isolated island power supply. However, the existing analysis model cannot meet the requirement of its performance evaluation and circuit parameters design. This paper proposes a high-accurate time-domain steady-state analysis model for MMGC, where the coupled relationships among the load, the MMGC, and the dc-side system can be fully reflected; the amplitudes and phase angles of electrical quantities, including their harmonic components, can be directly calculated. Then, the influence of <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LC</i> filters on submodule capacitor are studied. The study found that the submodule capacitance is highly correlated to the filter capacitance and almost uncorrelated to the filter inductance. It is also found that the filter capacitance selection should consider the load characteristic; a larger filter capacitance is required in the inductive load supply scenario. Finally, the studies are verified by both simulation and experiment.

A customized electricity pricing approach that considering the gaming ability of users and the new power sales company

The prevailing customized electricity pricing methods in China primarily utilize a single power price, which is an extra service cost charged per kWh. This paper suggests a customed power pricing optimization method that takes into account not only electricity quantity (kWh), but also capacity (kVA), and considers the gaming ability of both users and the electricity retail company. Firstly, the method for determining level of the quality of power is introduced in this paper, which is based on various quality of power indices Next, an optimization model for the customized electricity pricing is suggested, which takes into account the gaming ability of both users and the new power sales company (NPSC). Lastly, this paper conducts a case study of four representative users situated in an industrial park in Chengdu, Sichuan province to demonstrate the practical application of the proposed approach. The findings indicate that the suggested approach can allocate customized electricity charges between capacity and electricity consumed by users in a rational manner, thus enhancing the efficiency of production equipment for users.

Intelligent Island detection method of DC microgrid based on Adaboost algorithm

Aiming at the problems of large detection blind areas and difficult threshold settings in traditional passive islanding detection methods, this paper proposes an intelligent passive islanding detection method based on the adaptive boosting (Adaboost) algorithm. This method first uses feature screening technology to obtain the key feature electrical quantities of DC microgrid islands and form a sample set, and then rely on the Adaboost algorithm to generate a high-precision island classification model to realize the detection and classification of DC microgrid operation status. It has the advantages of automatic setting threshold, small detection blind area, and high accuracy. In addition, aiming at the problem that the classification results of the intelligent islanding detection algorithm based on machine learning cannot be directly used as the islanding discrimination results, an islanding criterion method based on the sliding window algorithm is added on the basis of the classification algorithm. This method realizes the accurate detection of the DC microgrid islanding operation state by the secondary analysis and judgment of the classification results of the islanding classification model. Finally, a DC microgrid model is built to simulate and verify the proposed method. The results show that the method can quickly and accurately complete the islanding detection of the DC microgrid.

State of charge estimation for “LiFePO4 - LiCoxNiyMn1-x-yO2” hybrid battery pack

In addition to reconciling the cost and energy density of the battery pack, the “LiFePO4 - LiCoxNiyMn1-x-yO2” (LFP - NMC) hybrid battery pack can also effectively reduce the risk of thermal spread, so it has been initially applied in the industry. However, the electrochemical properties of the two batteries are very different, so realizing the state estimation of the single cell is the key to the effective management of the hybrid battery pack. Therefore, a novel state estimation method for hybrid battery packs is proposed in this paper. First, the easy-to-estimate NMC as the “ruler” to estimate the SOC of the LFP based on the principle of the same amount of electricity in the series cells. Second, through the design of a “difference state observer (DSO)” with fuzzy logic, continuous feedback correction of electricity is realized. Results from the experiments have verified that when the LFP is connected to a 200 Ω resistor to simulate the self-discharge difference along with sensor errors, the algorithm can control the SOC estimation error of the LFP to about 1 %, which has excellent estimation accuracy. In addition, the algorithm has good robustness. In the scenario with current and voltage sensor errors, the SOC estimation error of LFP is within 2 %. Finally, the capacity and SOC of the hybrid battery pack are solved by using the “Electric quantity - Capacity Scatter Diagram” (ECSD), and the estimation errors are within 1.5 Ah and 1 %, respectively.

Method of Calculation the Load Rates and the Unbalance Rates of the Current of the Phases in the MV/LV Network of the Sales and Service Center Lemba in Kinshasa

In this article, we discuss the calculation of load and current imbalance rates, which is a steady-state study of the distribution network that consists of determining, for each subscriber station, the operating rate of the installed power transformer and the current difference between two phases of the MV/LV distribution station. Knowing the allowable currents of each low-voltage phase of the subscriber substations from the busbars as well as the rated current of the substations transformer, we can calculate, secondly, the average currents and load factors of the substations including the differences between the currents and their unbalance factors in the low-voltage distribution power lines. The mathematical equations of the electrical quantities of the power system facilitate the evaluation of the performance of the power transformer. These equations confirm that the variation in load ratio and current imbalance of three phases are closely related to the current draw of the allowable loads at each phase.

A Method for Judging the Arc-Extinction Time of Resonant Grounding System Based on Frequence Difference

In the resonant grounding system, the accurate judgment of arc-extinction time has guiding significance for the line selection of grounding fault, the evaluation of the arc suppression effect, and the extraction and utilization of transient information after arc extinction. Aiming at the single-phase grounding fault of resonant grounding system, this paper analyzes the frequence change characteristics before and after arc extinction. It is found that the frequence of zero-sequence electrical quantity before arc extinction is power frequence, and it changes after arc extinction. It is used to construct single-frequence methods and dual-frequence methods for judging arc-extinction time. As a tool for dynamic frequence measurement, SOGI-FLL is utilized to realize the engineering application of the method for judging arc-extinction time. The method’s accuracy is proved by Matlab/Simulink simulation and field test.