Loss Calculation Method Research Articles

Temperature field analysis of dry iron core reactor

The hot spot temperature of a dry-type iron core reactor is important for its pre-design and optimal design. To precisely study the hot spot temperature and temperature distribution law of dry iron core reactor, this paper firstly studied the loss of reactor, including coil loss and core loss, and obtained the calculation method of reactor loss. Then, the normal working environment of the dry core reactor is analyzed, and the temperature field simulation is carried out for a three-phase dry core reactor with an inductance value of 11.561 mH and capacity of 10 kV, and the hot spot temperature and temperature distribution law of this reactor are obtained and analyzed through reasonable material setting and heat dissipation method setting. Finally, the accuracy and validity of the simulation results are verified by the actual temperature rise experimental data. The research results provide a theoretical basis for structure optimization and online monitoring of the dry core reactor.

Search for charm-quark production via dimuons in neutrino telescopes* *Supported by the National Natural Science Foundation of China (11875189, 11835005) and Shanghai Jiao Tong University under the Double First Class Start-up Fund (WF220442603)

Dimuon events induced by charm-quark productions from neutrino deep inelastic scattering (DIS) processes have been studied in traditional DIS experiments for decades. The recent progress in neutrino telescopes makes it possible to search for such dimuon events at energies far beyond the laboratory scale. In this study, we construct a simulation framework to calculate yields and distributions of dimuon signals in an IceCube-like km3 scale neutrino telescope. Owing to the experimental limitation in the resolution of double-track lateral distance, only dimuons produced outside the detector volume are considered. Detailed information about simulation results for a 10-year exposure is presented. As an earlier paper[Physical Review D 105, 093005 (2022)] and ours report on a similar situation, we use that paper as a baseline to conduct comparisons. We then estimate the impacts of different calculation methods of muon energy losses. Finally, we study the experimental potential of dimuon searches under the hypothesis of single-muon background only. Our results based on a simplified double-track reconstruction indicate a moderate sensitivity, especially with the ORCA configuration. Further developments on both the reconstruction algorithm and possible detector designs are thus required and are under investigation.

COMPARISON OF 2 METHODS OF BLOOD LOSS CALCULATION AGAINST THAT BY VISUAL OBSERVATION BY ANAESTHETIST IN MAJOR SURGERIES

Introduction: Accurate assessment of blood loss is a problem in specialities like neurosurgery and orthopaedic surgeries where large volume of uid is used for irrigating wounds during surgery. Blood loss quantication remains unreliable and inaccurate and hence the debate between surgeons and anaesthetist pertaining to whether to transfuse or not and on what basis remains a problem.We studied 2 methods of blood loss calculation based on observation and calculation and compared them with visual blood loss. Aims: “Comparison of 2 methods of blood loss formula and their comparison based on visual observation by anaesthetist in major surgeries.” Objectives :(1)Calculation of blood loss based on haematocrit. (2) Calculate blood loss based on haemoglobin (3)Persistence of anaemia based on lab haemoglobin values in patients pre and post operatively (4) Comparing formula 1 & 2 to nd the appropriate formula for blood loss against visual loss on gauze and mops and suction. This randomised trial was conducted Materials And Methods: on 85 patients at Dr. D.Y.Patil medical college ,pune. Since different methods were used we dened 2 units measured blood volume loss which was calculated by the Blood volume loss formula and measured hemoglobin mass loss calculated by the hemoglobin mass loss formula. The actual blood loss was assessed Result: visually in terms of number of gauze pieces and mops used. In patients with preoperative hemoglobin less than 12g the mean actual blood loss is statistically similar to Blood volume loss formula while in patients with preoperative hemoglobin more than 12 the mean actual blood loss is statistically similar to hemoglobin mass loss formula The mean actual blood loss is statistically si Conclusion: milar to Hemoglobin mass loss in patients with preoperative hb more than 12 and blood volume loss in patients with preoperative hemoglobin less than 12.

A real-time three-phase line loss calculation method for distribution network based on feeder terminal unit

Combined with the monitoring data of the new distribution network Feeder Terminal Unit (FTU), an innovative three-phase real-time line loss calculation method based on the feeder segment rather than the entire feeder as the basic calculation unit is proposed. This method uses the variable structure dissipative network theory, divides the feeder into feeder segments, and conducts mathematical modeling for each equipment in the segment based on the feeder segment. The detailed line loss of each equipment makes the line loss distribution in the system clear at a glance, which is convenient for operation and maintenance personnel to scientifically manage and carry out distribution network line loss analysis and calculation, and provides a favorable basis for further optimization of the distribution network system.

ОСОБЛИВОСТІ ПРАВОВОГО РЕГУЛЮВАННЯ УРБОЕКОЛОГІЧНИХ ВІДНОСИН У ДОБУ РОСІЙСЬКО-УКРАЇНСЬКОЇ ВІЙНИ

The article is devoted to the analysis of the features of the legal regulation of urban-ecological relations during the russian-Ukrainian war (2014-2022). It has been revealed that the directions of development of the system of urban-ecological security, laid down in the current strategies of the national, sectorial, and regional levels, without taking into account the unprecedented military impact on the environment, should be considered rather fragmented and not fully in line with the European integration aspirations of Ukraine. It was revealed that the formation of the legal framework for urban-ecological relations at the level of individual cities and urban facilities took place before the start of full-scale aggression, mainly in areas related to water supply and water resources, protection of atmospheric air and historical monuments, land use, landscaping, urban monitoring, digitalization, cross-border cooperation. In the case of a techno- or anthropogenic impact, it is proposed to proceed from the presence of a composition of impact relations, in which the active action of the subject of influence (the subject of the origin of the impact) on the object of influence can have consequences for the subject of perception (the subject affected by the influence) through the object of perception. The prospects for the legal regulation of relations on compensation for environmental damage and damage caused by military influence, which are accompanied by a certain inconsistency, are given. In particular, after the adoption of relevant normative legal acts of a sub-legal nature, the question arose of consideration of laws on: 1) compensation for damage caused to the victim as a result of armed aggression, 2) legalization of loss calculation methods in accordance with internationally recognized ones, 3) the mechanism of confiscation of the property of the aggressor country in order to carry out work on the restoration of Ukraine, 4) digitalization of data on the damage caused and the profile of the victim.

Analysis of special technical problems of wireless charging at UUV docking stations and a new underwater electromagnetic coupler

In order to solve the problem of insufficient range of autonomous underwater vehicles, underwater docking stations deployed on the seabed can wirelessly charge autonomous underwater vehicles through recyclers. Compared with traditional wireless charging of electric vehicles, wireless charging based on underwater docking stations has many special technical problems that need to be further understood and deciphered. This paper introduces the basic functions of the docking system and the docking process, and then focuses on the following three aspects of wireless charging at docking stations: firstly, the design of the coupler to suit the underwater vehicle and the complex marine environment, the coupler mechanism should match the shape and structure of the underwater vehicle, and the coupler should have a high resistance to deflection; secondly, the influence of the seawater medium on the wireless charging system. The impact of seawater medium on the wireless charging system is analysed, and the equivalent circuit model considering seawater eddy currents and the equivalent circuit model considering cross-connecting capacitance effects are established respectively; thirdly, the design of communication-independent wireless charging system. The existing eddy current loss calculation methods are analysed for the key technical problem of eddy current loss in seawater. A new type of electromagnetic coupler is proposed, the structural characteristics of the coupler are introduced and the simulation results show that the new coupler has a strong anti-deflection capability.

Numerical Calculation Method of Spanwise Icing Characteristics and Performance Loss of Three-Dimensional Vertical Axis Wind Turbine Blades

Most icing studies use 2D or quasi-3D models, ignoring the effects of blade span and tip icing. In this paper, a new model for predicting 3D vertical axis wind turbine blades icing by supplementing the blade span is established, the icing characteristics of blades under multiple working conditions are simulated step by step from the time scale, and the unsteady icing laws are compared and analyzed. Ice properties and surface temperature distribution determine the corresponding deicing power. The analysis results show that the unfrozen water film flows in the spanwise direction of the blade, resulting in a smaller icing limit on the pressure surface than the two-dimensional model, which indicates that the chordwise anti-icing structure can be set in a small range. At the same time, the annular ridge ice formed at the end of the blade slows down the reduction rate of the lift-drag ratio of the blade, effectively reducing the influence of the leading edge ice shape on the aerodynamic performance of the blade. Finally, the critical ice melting power density required to reach equilibrium temperature at the leading edge of the blade is reduced by about 11% compared to the trailing edge due to the increased thermal resistance of the gas-to-blade matrix interface by the ice layer.

A novel irrigation canal scheduling model adaptable to the spatial-temporal variability of water conveyance loss

The water conveyance loss of irrigation canals shows significant spatial-temporal variability both along the canal reach and over time. An accurate representation of these variances in irrigation canal scheduling is essential to reduce water conveyance loss. However, the existing optimal irrigation scheduling models (OISMs) still have deficiencies in dealing with spatial-temporal variability of water conveyance losses, which seriously limits the model performance in many irrigation areas with high spatial-temporal variability. Borrowing a concept from hydrology, we propose a Dynamic Calculation Method of canal water conveyance loss (DMWCL), in which antecedent water conveyance index (AWCI) is defined to represent the effects of antecedent soil water content upon infiltration losses, and the integral-flow balance method is adopted to describe the characteristics of canal discharge decreasing along the canal reach. Based on the DMWCL, we present a novel canal scheduling model with the potential to adapt to spatial-temporal variability (DMWCL-CS). The new model is applied to the Hetao Irrigation District, Inner Mongolia, a typical agricultural watershed in China. Our results across the case studies show that the canal water delivery schedule derived by the DMWCL-CS model reduces water conveyance loss and improves irrigation performance, ranging from 2.49 million m3 to 10.60 million m3 in 2014 and from 0.60 million m3 to 6.17 million m3 in 2016, respectively, compared to that of three additional models. Interestingly, we find that the water delivery schedule of the DMWCL-CS model accelerates the wetting process of the canal bed soil to reduce the water conveyance loss and increases the discharge to adapt to the characteristics that the discharge decreases along the canal reach. The DMWCL-CS model provides essential insights for irrigation managers to formulate a canal water delivery schedule that adapts to spatial-temporal variability. The proposed framework is generic and can be integrated into any OISM.

A Theoretical Energy Loss Calculation Method for Transformer District Based on Improved Convolutional Neural Networks

Energy saving and emission reduction are important in the industrial field, and the transmitting loss of electric energy has been getting wide attention. The development of advanced metering infrastructures and information technology has enabled a massive accumulation of electricity data. Therefore, data-driven method is prospective to be applied to the calculation and analysis of energy loss. In order to establish an efficient data-driven theoretical energy loss calculation method for the transformer district, the following researches are carried out in this article: 1) In order to determine the input variables for the calculation model, the optimal types and number of input variables are determined through sample preclassification, grey correlation analysis and the 10-fold cross-validation method; 2) The structure of the convolutional neural networks is improved for accurately revealing the nonlinear relationship between multidimensional input data and theoretical energy loss; 3) A sample expansion method for transformer district based on generative adversarial networks is proposed, and the effect of the size of samples on the theoretical energy loss calculation in transformer district is analyzed. The simulations show that the proposed method results in acceptable calculation accuracy, training efficiency, and generalization ability.

Improvement on Loss Separation Method for Core Loss Calculation Under High-Frequency Sinusoidal and Nonsinusoidal Excitation

The original loss separation formula introduced by Bertotti has long been utilized mainly for low-frequency sinusoidal applications. In this article, the traditional method is improved to fit into the core loss calculation under higher frequency sinusoidal and nonsinusoidal excitations, verified by the measured data of nanocrystalline material that is often used in medium-frequency transformers (MFTs). For high-frequency sinusoidal waveform, it is proposed that the exponent of the excess loss needs to be reidentified, and it is necessary to consider the skin effect for hysteresis and eddy current loss calculation under broader frequency scope. When the core is supplied with nonsinusoidal excitation (square and rectangular waveform), a new empirical method is derived based on the concept of effective frequency and the loss separation results, with which the estimation accuracy is greatly guaranteed compared to empirical methods originated from the Steinmetz equation such as improved generalized Steinmetz equation (iGSE). Due to clear separation of loss components, the new method has the potential to precisely predict losses for higher frequency applications.

Calculation Method of Core Loss Under Intermediate Frequency Excitation

Based on Brockhaus magnetic measurement system, the magnetic properties of GT100 ultra-thin silicon steel under middle and high frequency sinusoidal excitation are measured. Based on the Preisach model, the static hysteresis and loss characteristics are simulated accurately. In addition, an improved loss model was proposed. The formula of eddy current loss was improved according to skin effect principle, and the statistical parameter V0 of abnormal loss was adjusted by iterative algorithm. The simulation results of sinusoidal dynamic hysteresis loop and iron loss at different frequencies and different flux densities are compared with the measured results, which verifies the accuracy and versatility of the improved model. In addition, the influence of increasing frequency and flux density on total loss is also studied.

Continuous Line Loss Calculation Method for Distribution Network Considering Collected Data of Different Densities

In order to find the causes of statistical line loss abnormalities and propose better loss reduction strategies, it is necessary to improve the accuracy of theoretical line loss calculations. Since Distributed Generation (DG) access to the distribution network causes variability of power flow in the distribution network within a short period, the error of the traditional line loss calculation method increases. For the line loss calculation of medium-voltage distribution networks containing DGs with high-density collection data, a continuous line loss calculation method for the distribution network was proposed, aiming at improving the accuracy compared with the traditional line loss calculation method. The proposed method makes full use of the high-density collection data on the dispatch side and DG side, distributing the supply power to each load node by power to calculate real-time power flow, thus obtaining a more credible line loss value. The effectiveness and accuracy of the proposed method were verified in the IEEE 17-node distribution system.

Rain-flow counting method for hysteresis loss computation in a switched reluctance drive

A new algorithm is applied in order to compute the loss distribution in a Switched Reluctance Drive, with a particular focus on the contribution of minor loops to the hysteresis loss. The computational method for fast iron loss calculation is based on the modified Steinmetz equation, and the rain-flow counting method is applied to account for minor loops effects. Adjustment coefficients are used to consider the impact of different flux-density waveforms, with validation using FEA simulations and experimental testing.

Line Loss Interval Algorithm for Distribution Network with DG Based on Linear Optimization under Abnormal or Missing Measurement Data

Data collection is more difficult in distribution network than transmission networks since the structure of distribution networks is more complex. As a result, data could be partly abnormal or missing, which cannot completely describe the operation status of distribution network. In addition, access of distributed generation (DG) to distribution network further aggravates the variability of power flow in distribution network. The traditional deterministic line loss calculation method has some limitations in accurately estimating the line loss of distribution network with DG. A line loss interval calculation method based on power flow calculation and linear optimization is proposed, considering abnormal data collection and distribution network power flow variability. The linear optimization model is established according to sensitivity of line loss to the injected power and sensitivity of transmission power of first branch to the injected power. Introducing the scheduling information into the optimization model, a reliable line loss fluctuation interval can be obtained which actual line loss locates. The effectiveness of the proposed algorithm is verified in IEEE 33-bus distribution network system.

Reduction of power conversion losses in AC-DC coupled hybrid micro-grid under grid distorted voltage scenario

As the power consumption rate is high, the supply from fossil fuels is not enough to meet consumer demand. Further, the depletion of fossil fuels and environmental concern forces the extraction of power from low carbon fuels causes generation problems due to its uncertainty and intermittent in nature. So, low carbon fuels such as wind, solar, etc. can therefore, be incorporated into a more efficient hybrid micro-grid system. In the current dominated AC coupled hybrid micro-grid system, a significant amount of power conversion losses is increased due to more power conversion stages. Therefore, this research paper proposes an appropriate loss calculation method (i) to validate AC-DC coupled hybrid micro-grid system has minimum power conversion losses than the AC coupled hybrid micro-grid system, (ii) appropriate power sharing between AC and DC bus and (iii) grid current harmonics mitigation. To validate this method, different case studies are performed in MATLAB simulation by considering undistorted and distorted grid conditions with variation in renewable energy sources. The observed results demonstrate that the merits of the AC-DC coupled hybrid micro-grid system has been validated over AC coupled hybrid micro-grid system.

Noise mapping technology of high-speed railway based on GIS

In order to promote the application of noise map in high-speed railway noise management, the high-speed railway noise map drawing technology based on the combination of noise prediction model and geographic information system (GIS) is studied. Firstly, according to the distribution characteristics of noise sources and line structure characteristics of high-speed railway, the prediction model of multi equivalent sound sources and the calculation method of sound barrier insertion loss of high-speed railway are optimized; secondly, a three-dimensional geographic information model of a high-speed railway is built in GIS software, and the railway noise prediction technology based on the model is developed again; then, the noise of discrete nodes is calculated, and the continuous noise distribution map is drawn by spatial interpolation. The research results show that the comparison error between the noise map of a high-speed railway drawn by this technology and the measured results is less than 1 dB (A), which verifies the accuracy and practicality of the high-speed railway noise map, and can be used as a reference for the railway noise management department to formulate noise control countermeasures.

Research on Short-Term Low-Voltage Distribution Network Line Loss Prediction Based on Kmeans-LightGBM

Due to the lack of data quality in real production environment, the traditional line loss calculation method cannot be applied, thus through the investigation of various information systems’ operation in power supply enterprises, a short-term low-voltage distribution network line loss prediction algorithm based on Kmeans-LightGBM is proposed. Operating data quality evaluation system of low-voltage distribution network was set up based on Hadoop platform, the feature dimensions were expanded by feature engineering, then those with no multicollinearity and high correlation with the line loss were selected, data normalization was again performed, Kmeans clustering algorithm was used to cluster the area and then, LightGBM algorithm was used to predict the classes within the area of line loss. Finally, the line loss of the numerical inverse normalization was found and validated with Beijing Power Grid of a low-voltage distribution network. By comparison, the model’s prediction accuracy is found to be higher than BPNN, FOA-SVR and traditional LightGBM.

Line Loss Prediction of Distribution Network Based on BP Neural Network

Distribution network line loss calculation refers to the calculation of the electrical energy loss, which is generated by all components in a distribution network system in a given period of time. Distribution network, as the end of the power network, is directly connected with users; there are many equipment on the network; the system has impedance, electric energy in the process of conversion, transmission and distribution with a lot of loss, so the calculation of distribution network line loss has very important economic significance. In addition, with the development of power network construction, the rationality of distribution network topology design and the comparison of practical effects of various measures need the guidance of line loss calculation. Line loss and line loss rate is one of the main criteria to reflect the operation of distribution system. Reducing line loss of distribution system is very important for the effective use of power and economic operation of distribution system. In order to better find the effective reduction method and lay the foundation for the scientific establishment of linear contraction targets. This study uses a line loss calculation method based on BP neural network. The method uses the super matching property of the network to map the complex nonlinear relationship between the line loss and the characteristic variables and stores the evolution of the line loss changes with the changes of the structural and operational variables of the distribution line. On the basis of analyzing the theoretical methods, management methods, and various loss reduction measures of power loss calculation, this study also analyzes the status quo and existing problems of line loss analysis and calculation and collects data from line loss calculation and theoretical line loss calculation methods. This study discusses in detail the method and idea of the application of the improved neural network in the estimation of distribution network line loss, and it is used to predict the line loss in a certain area, and the prediction result is good.

IGBT Energy Losses Analysis and Heat Dissipation System Design of Three-level Inverter

Abstract According to the needs of the design and development of three-level inverter, the paper introduces the design process of the inverter cooling system in detail. Firstly, this paper proposes a calculation method of the energy losses in the insulated gate bipolar transistor(IGBT) and freewheeling diode(FWD), and calculates the energy losses of the IGBT module in the inverter according to the method. Otherwise, a set of the inverter forced air cooling heat dissipation system is designed, and the simulation of the finite element analysis is used for the analysis and optimization of the system. Finally, the test shows that the temperature rise of the IGBT module is within the reasonable range, which verifies the availability and feasibility of the proposed method and the designed system.

Canonical Face Embeddings

We present evidence that many common convolutional neural networks (CNNs) trained for face verification learn functions that are nearly equivalent under rotation. More specifically, we demonstrate that one face verification model’s embeddings (i.e., last–layer activations) can be compared directly to another model’s embeddings after only a rotation or linear transformation, with little performance penalty. This finding is demonstrated using IJB-C 1:1 verification across the combinations of ten modern off-the-shelf CNN-based face verification models which vary in training dataset, CNN architecture, method of angular loss calculation, or some combination of the 3. These networks achieve a mean true accept rate of 0.96 at a false accept rate of 0.01. When instead evaluating embeddings generated from two CNNs, where one CNN’s embeddings are mapped with a linear transformation, the mean true accept rate drops to 0.95 using the same verification paradigm. Restricting these linear maps to only perform rotation produces a mean true accept rate of 0.91. These mappings’ existence suggests that a common representation is learned by models despite variation in training or structure. We discuss the broad implications a result like this has, including an example regarding face template security.