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Electrifying aircraft, a crucial advancement in the aviation industry, aims to cut pollutive emissions and boost energy efficiency. Traditional aircraft depend on fossil fuels, which contribute significantly to greenhouse gas emissions and environmental pollution. Despite progress in electric propulsion and energy storage technologies, challenges such as low energy density and integration issues persist. This paper provides a comprehensive thematic and bibliometric analysis to map the research landscape in aircraft electrification, identifying key research themes, influential contributors, and emerging trends. This study applies natural language processing to unstructured bibliographic data and cross-sectional statistical methods to analyze publications, citations, and keyword distributions across various categories related to aircraft electrification. The findings reveal significant growth in research output, particularly in energy management and multidisciplinary design analysis. Collaborative networks highlight key international partnerships, with the United States and China being key research hubs, while citation metrics highlight the impact of leading researchers and institutions in these countries. This study provides valuable insights for researchers, policymakers, and industry stakeholders, guiding future research directions and collaborations. [ABSTRACT FROM AUTHOR]

In the field of electric carbon, the mapping relationship between carbon emission flow calculation and power flow calculation was studied by combining techniques such as current trajectory tracking, carbon flow trajectory analysis, power system flow calculation methods, and electric network analysis theory. By delving into the mechanism between these two factors, a better understanding of the correlation between them can be achieved. In addition, by using time series data, graph attention neural networks (GNN), distributed computing technology, and spatiotemporal computing engines, carbon emission fluctuations can be decomposed and a high-frequency "energy-electricity-carbon" integrated dynamic emission factor can be achieved. Through the spatiotemporal distribution patterns of this dynamic factor in multiple dimensions, the carbon emissions from key industries in cities can be accurately calculated. In this paper, the LSTM-GAT model is used as the core to construct a key carbon emission prediction model for cities. The study focuses on the power plant, chemical industry, steel, transportation industry, and construction industry, which are high energy-consuming industries with an annual electricity consumption of more than 100 million kWh in a major city of China. By analyzing the entire life cycle from power generation to electricity consumption and conducting current flow analysis, monthly, weekly, and daily carbon emission calculations were performed. Additionally, other factors such as the industrial development index, GDP, coverage area of power generation enterprises, regional population, size, and type of power-consuming units were included in the comprehensive calculation to build a measurement system. By conducting experiments and analyzing historical data, we have found that the LSTM-GAT model outperforms the single models of GCN, GAT, LSTM, GRU, and RNN in terms of lower error values and higher accuracy. The LSTM-GAT model is better suited for predicting carbon emissions and related indicators with an accuracy rate of 89.5%. Our predictions show that the carbon emissions will exhibit a slow growth trend in the future, while the carbon emission intensity will decrease. This information can provide a scientific basis for government decision-making. [ABSTRACT FROM AUTHOR]

A run‐of‐the‐river power plant is a renewable energy source used for electricity production. Its power output depends on the varying water flow rate over time, which can impact the reliability of the electric network. Previous research has not studied the effects of water flow rate and temperature variations on the hazard rate of the plant's components. This paper addresses this gap by investigating the impact of these variations on the reliability of electric networks with run‐of‐the‐river power plants. The analysis considers the hazard rates of the plant's components, incorporating the relationship between hazard rate and temperature based on the Arrhenius law. Parameters such as power output, current, power loss, operating temperature, and hazard rate are calculated for different water flow rates and ambient temperatures. Numerical simulations on a test system are conducted to examine the influence of water flow rate and temperature on the reliability indices of the electric network. The results demonstrate that water flow rate and temperature significantly affect the hazard rates of run‐of‐the‐river power plants. This highlights the need to consider these factors in the reliability analysis of electric networks incorporating these renewable resources. [ABSTRACT FROM AUTHOR]

The field of microwave and millimeter-wave imaging systems is experiencing significant growth in research, primarily attributed to their versatile interaction capabilities with various materials. In the course of image reconstruction, the inverse scattering problem is resolved through either qualitative or quantitative means. The inverse scattering problem can be resolved by utilizing the truncated singular value decomposition (TSVD) algorithm, which is a suitable inversion method that can be employed when there is a need to discard a portion of data. The utilization of multi-frequency multi-static inversion techniques yields results that exhibit greater robustness and clarity when contrasted with single-frequency mono/bi-static configurations. However, it should be noted that the TSVD formulation may not be sufficient in practical experimental situations, as it fails to account for potential deviations in power among excitations at varying frequencies. As a result, it is imperative to perform a calibration process to standardize the power variations across different frequencies. The proposal outlines a calibration methodology that aims to achieve power equilibrium across various frequencies and facilitate the automation of imaging algorithms. The proposed calibration technique is evaluated and demonstrated through the use of a through-the-wall experiment. [ABSTRACT FROM AUTHOR]

This paper presents a methodological framework to evaluate the resilience, with the primary focus on performance degradation, of levee-protected electric power networks to flooding in a changing climate. To this end, a multi-disciplinary framework is established by integrating climate science, hydrology, and electric power network analysis. The framework quantifies the effect of climate change on flood hazard levels in a levee-protected area and the subsequent changes in the resilience of the electric power network. In the first step, the changes in the exposure of levee-protected regions to flooding hazard in a warming climate are calculated. Then, the probabilities of failure of power network components due to flooding under current and projected future climate are determined. Finally, the power system resilience index is used to assess the system resiliency for pre-flooding (baseline), historic flooding, and two projected future flooding scenarios. For demonstration, the proposed framework is applied to a levee-protected area in Northern California. The IEEE 118-bus standard test system is employed to represent the power network in the study area. Results reveal that climate change can considerably decrease the system resilience of the levee-protected electric power network. The findings of this study can contribute towards more resilient power network systems under a changing climate. [ABSTRACT FROM AUTHOR]

The swelling-induced mechanical response of homogeneous anisotropic gels under free conditions and uniaxial loading is investigated. Semi-analytical and numerical analyses show that fibers hamper solvent uptake regardless of their orientation, causing the several changes in shape that occur. Finally, we verified that fibers do not significantly alter relaxation time, which determines the steady state under free–swelling conditions. [ABSTRACT FROM AUTHOR]

To accurately obtain the switching characteristics of insulated gate bipolar transistors (IGBT), this paper proposes an IGBT's transient analysis model (TAM) based on the finite state machine (FSM). Firstly, the IGBT switching process in the basic converter unit is segmented in the time domain, and the circuit equations among the variables are obtained based on Kirchhoff's law. Then, the switching mechanism and parameters of the IGBT are decoupled based on time segmentation, and clarifying state equations and the transition events for each stage. Subsequently, all the stages and events are modeled in an FSM, thus establishing the IGBT's TAM, and it was realized the Stateflow toolbox of Matlab/Simulink. Finally, some experiments were performed on IGBTs with different current and voltage. The results show that the TAM can accurately describe the switching characteristics of IGBT and is suitable for different voltage and current levels. [ABSTRACT FROM AUTHOR]

Dispersive surface waves on an acoustic 2D metamaterial, a metasurface consisting of membranes on a rigid surface, have certain propagation characteristics with potential applications for resonance based sensing and subwavelength imaging. The trapped modes of the system that is responsible for the dispersive properties of these acoustic waves are analyzed through modal analysis for a small linear membrane array to obtain the mode shapes, resonant frequencies, quality factors, and wavenumbers. Transient analysis is used for larger arrays to obtain the dispersive properties of the traveling waves and is compared to the modal analysis. Equifrequency contours of the 2D metasurface illustrate interesting features of the metasurface at different frequency regimes around the membrane resonance. These features include anisotropic wave propagation, directional band gap, negative refraction, and complete band gap. Effects of membrane pitch, randomness of resonance, and aperiodic membrane spacing on dispersion, band gaps, and quality factor of the trapped modes on the metasurface are investigated as they relate to realistic implementations for different applications. [ABSTRACT FROM AUTHOR]

This paper presents a mho distance relay simulation based on the phase comparison technique using a typical electrical power systems analysis software for two cases: when the operation state is close to the static voltage limit and during a dynamic perturbation in the system. The paper evaluates the impedance variations caused by complex voltage values, the mho polarization, and the comparator operating region into the complex plane. In addition, the paper found the information for the dynamic pe1turbations from the outputs considering a mid-term stability program. The simulation of the mho-phase comparator in the static voltage proximity limit detects unit distance elements with impedance measured close to reach the threshold in the steady-state. Dynamic mho simulations in the complex plane are successfully tested by plotting time phase difference curves on the comparator input signals. Relay programmers can use these curves to analyze other phase comparators applications and the corresponding models in the complex plane. [ABSTRACT FROM AUTHOR]

Solid armatures in electromagnetic rail launchers have to undergo severe electromagnetic, mechanical, and thermal stresses. These stresses are unevenly distributed in the armature mainly due to the velocity skin effect. Contrasting this effect reduces the peak to average ratio of the stresses and allows better performance of the device. In this article, the behavior of a transposed multiconductor solid armature is numerically investigated by the research code electric network for electromagnetics (EN4EM) developed at the Department of Energy, System, Territory and Construction Engineering (DESTEC), University of Pisa, Pisa, Italy. The code is based on an integral formulation that reduces the magnetic diffusion problem in the analysis of a time-varying electric network. The code enables a strong electromechanical coupling and allows accounting for currents’ distribution in the rails and in the armature due to the proximity and “ordinary” skin effects, as well as the velocity skin effect. Preliminary computations have shown an improved (more regular) current density distribution in the armature. This allows increasing the total current on the armature without reaching the melting temperature in the armature. Improved performance of the launcher with transposed armature is predicted. [ABSTRACT FROM AUTHOR]

Resilience and functionality of a community after an extreme event rely on performance of several interdependent systems. Data from historic events show that power network seems to be the most critical lifeline, given the dependency of water, communication, transportation, and gas networks on power. This paper focuses on modeling of the performance of an electric network, after an earthquake, for application in analysis of interdependent systems. The paper proposes a streamlined approach to analyze post-earthquake performance of an electric network to identify regions in a community without power. The proposed approach quantifies damage at the component level using fragilities and a capacity index parameter that measures operability. System level network analysis, based on the capacity of the network, is completed to measure and compare power flow before and after the earthquake. A limiting ratio is defined to identify dark versus bright regions. The procedure is validated for two case studies. [ABSTRACT FROM AUTHOR]

The investigation of the thioxophosphine (PS) formation from different reaction paths is successfully performed and presented in this paper. The PH3+SH1 reaction is likely to yield the intermediates PH22+H2S through an energy barrier of 2.8 kcal mol-1. However, the next step is the H2PS2 formation, which has a too high energy barrier, 52.6 kcal mol-1. The PH3+S1 reaction path is the likely source of the HPS1 molecule. The other possibilities are the PH1+H2S, PH22+SH1, and PH3+H2S reactions, but they are spin forbidden and energetically unfavorable for the HPS1 and PSH1 formations. On the other hand, the PS2 formation is more likely to happen by the PH1+SH1 reaction. The PH22+S1, PH3+SH1, P2+H2S, and P4+H2S reactions are also favorable in terms of energetics; however, these reactions are spin forbidden. The chemical mechanism for the PS2 formation is now presented in more details, which is of great importance in the atmosphere of Jupiter and Saturn, and in interstellar medium. [ABSTRACT FROM AUTHOR]

The influence of laser intensity on absorption line broadening was investigated. Laser absorption spectroscopy was applied to low-pressure plasma, and the translational temperature deduced from the Doppler width was found to increase with laser intensity; this was in contrast to the conventional laser theory. Consequently, the dependency of absorption saturation on the Doppler frequency was considered. The predicted variation in broadening width with laser intensity showed a good agreement with the measurement. In addition, we obtained a correction factor for the temperature measurement at high laser intensity. [ABSTRACT FROM AUTHOR]

This paper evaluates and analyze wired network topologies, the analyze shows the advantages and disadvantages for each topology and the best use for each topology in term of area and utilized. The main aim of this paper to investigate which topology is suitable for medium organizations with large amount of data handled through the network. Further investigate has been done using Net Sim as simulation program to prove the result. [ABSTRACT FROM AUTHOR]

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Parametric problems in the transient analysis refer to the investigations of the relationship between parameters and dynamic behavior. To solve parametric problems, we propose a Galerkin method-based polynomial approximation. The proposed method uses a series of polynomials combined with coefficients to approximately represent state variables with parameters, where the Galerkin method is introduced to determine the coefficients. Thereby, the relationship between parameters and dynamic behavior is established through the polynomial expressions. Because models in power system transient analysis are a set of complicated differential-algebraic equations, practical issues related to the non-polynomial model terms, parameterization of initial operation point are discussed in this paper. The proposed method is tested on a three-machine system and the IEEE 145-bus test system. The case studies show that compared to trajectory sensitivities, the proposed method can maintain high accuracy in cases of large parameter variations and strong non-linearity. We also illustrate that the validity of the proposed method for parametric problems like trajectory approximation, finding the critical parameter values and uncertainty quantification. [ABSTRACT FROM AUTHOR]

Due to random patterns of demand response from the consumer side and the unreliable nature of renewable energy resources, load flow balancing and transient stability become challenging issues in power systems. They are even more challenging in cases of multiple interval three phase (L-L-L) faults (MITPFs), which arise in power systems due to power quality disturbances. The intent of this work is to examine the influence of MITPFs on renewable energy resources (RERs) for load flow balancing and transient stability analysis. Wind turbine power dispatchability and uncertainty have a significant impact on load flow balancing and transient stability, especially in cases of occurrence of MITPFs. Probabilistic modeling is performed in this paper to formulate the complexity of randomness for load flow balancing through a smart node and transient stability analysis through a unified power flow controller. The proposed probabilistic algorithm is based on the deviations between generation and demand response patterns due to an MITPF. An autocorrelation expansion is applied to approximate the randomness of probabilistic variables between the forecast generation and actual response pattern. Future contingencies can be predicted before disruptive changes arise due to the occurrence of an MITPF using the above probabilistic analysis. Simulation results show that the proposed algorithm outperforms existing alternatives and can achieve near optimal performance for a wide range of load variations and power quality disturbances in renewable-integrated power grids. [ABSTRACT FROM AUTHOR]

Information or data fusion concerns the aggregation, or combination, of probability measures. For example, in machine learning, statistics and signal processing, one may seek to ‘combine’ posterior distributions, [e.g. 1) Bayes classifiers or 2) posteriors over target states etc], arising from distinct but not necessarily independent sources. For example, sources might include partially disjoint trainers, or spatially distinct sensors correlated via state dependent measurements, etc. Data fusion is common in risk analysis where one is broadly interested in pooling expert opinions described by probability measures, and where it is often hard to assess and account for correlation among experts. The contribution of this work is the introduction of a broad class of data fusion rules that seek the combination of two (or more) probability distributions in the presence of non-zero, but unknown, correlation. We introduce rules that are improved in the sense that they are ‘closer’ to the true Bayesian result that would be computed if one could exploit knowledge of the correlation between the input distributions. We introduce these rules under the common algorithmic constraint of avoiding the so-called ‘double-counting’ of correlated information. The general framework proposed is based on homogeneous functionals. We examine the fusion performance and computational properties when using these functionals. We also consider distributed data fusion on (possibly) time-varying and incomplete network topologies and related convergence properties. [ABSTRACT FROM AUTHOR]

Abstract We present an extension of the combination of the Reciprocal Absorbing Boundary Condition (RABC) with Perfectly Matched Discrete Layers (PMDLs) for transient analysis of in-plane wave motion in a layered half-space. Due to the accuracy of RABC for multilayered systems, it is employed for domain truncation beyond vertical boundaries. PMDLs are particularly appropriate for handling the homogenous half-space and, herein, they are applied as excellent absorbers of waves into the half-space underlying the layered domain. Such a combination leads to solutions of problems of plane-strain wave-propagation in a layered half-space, directly in the time domain. Numerical examples are presented illustrating the accuracy, stability and effectiveness of the proposed combination. By combining two absorbing boundaries, the use of corner elements becomes unnecessary. Moreover, the long-term solution by RABCs-PMDLs is observed to be stable in the time-window of numerical examples. [ABSTRACT FROM AUTHOR]

The measurement of network topologies is of great significance to the multi‐scale expression and generalization of maps. The problem encountered in existing metrics is whether to use the approach of measuring a single type of information or measuring the overall information; however, redundancy can be calculated. In view of these problems, this article selects three types of information metrics that express compactness, heterogeneity, and discreteness in a network topology. The measurement model has been simplified, and the calculation has been improved. By comparing various methods and measuring the information entropy of area road networks, the simplicity and validity of the improved method are verified. [ABSTRACT FROM AUTHOR]

A new class of impedance networks is proposed in this paper. The proposed coupled-inductors-based impedance cells, called the series and the tapped switched-coupled-inductors, are employed within the (quasi) switched boost networks. The achieved impedance networks based on the proposed cells offer very high conversion gains with less-than-unity turn ratios (n < 1), which simplifies the realization of the magnetic element and at the same time reduces the number and size of passive components. The high boosting capability is achieved with small shoot-through durations that bring some additional advantages, such as low ratings of switching devices. The circuit analysis and operation concepts as well as a design procedure for the components of the proposed impedance networks are presented. Theoretical achievements are confirmed through experiments on a 220 W dc–dc converter laboratory setup. [ABSTRACT FROM AUTHOR]

The paper proposes a simple phasor estimator by utilizing the dictionary-based sparse representation of signals for control and protection applications in power system. It is also observed that the proposed method is found to be suitable for extracting the fundamental component of the signal required for protective relays with few number of samples. The simulations have been carried out to test the performance of proposed phasor estimator as per the requirements provided in IEEE C37.118.1a-2014 standard and also on a modified two-area power system. To further validate the effectiveness of proposed algorithm, it has also been tested on an analog radial power system simulator with fault in the laboratory experimental setup. The measured voltage and current signals are fed to the developed prototype of phasor measurement unit (PMU) with the proposed algorithm running for phasor estimation of signals in the power system. The real-time hardware and IEEE standard test results reveal that the proposed phasor estimation algorithm is able to estimate the phasor accurately in the presence of harmonics, decaying dc components, amplitude, and phase modulation, which are typically involved during disturbances. Furthermore, the proposed algorithm is able to estimate the phasor of a signal accurately with few measured samples, thus an analog-to-digital converter with lower sampling rate is suitable for developing a prototype of low cost P-class PMU for several applications in smart grids. [ABSTRACT FROM AUTHOR]

This paper presents the application of Belevitch theorem for pole-zero analysis of microwave filters synthesized with transmission lines and lumped elements. The scattering ($S$) matrix determinant ($\Delta $) based on the Belevitch theorem, aptly called Belevitch determinant, comprises poles and zeros that are separated in different half-plane regions. Using the Belevitch determinant, the poles and zeros of filter transfer functions can be determined separately with certainty, e.g., by applying the contour integration method based on argument principle. Note that the contour integration can be evaluated numerically without requiring complicated overall analytical expressions. The proposed method is able to solve the poles and zeros for filters synthesized with noncommensurate transmission lines and lumped elements, where the transform method and the eigenvalue approach are inapplicable. Several applications are discussed to demonstrate the use of Belevitch theorem and the contour integration method to determine the poles and zeros of various microwave filters on the complex plane. [ABSTRACT FROM AUTHOR]

This letter proposes a new algorithm for the fast extraction of symmetrical components from unbalanced three-phase signals. Being different from the conventional methods for the decomposition of positive and negative sequence components commonly realized at the cost of introducing significant delay, the proposed algorithm assumes the non-nominal dq-transformation to first produce the special d-axis and q -axis components, which will become the pure high-frequency ac signals, and then uses the typical half-cycle delay method to remove the unwanted negative or positive sequence component. Finally, the proper amplitude and phase angle coefficients can be easily calculated to compensate the remaining high-frequency d-axis and q-axis components before transforming them to the expected d-axis and q -axis values of corresponding symmetrical components. The performance of the proposed algorithm is evaluated through simulation and experiment results. [ABSTRACT FROM AUTHOR]

An efficient method is proposed for predicting the attenuation and distortion of the damped oscillation surges traveling on single-phase overhead lines under the influence of corona and frequency dependence of line parameters. The finite-difference time-domain algorithm is employed in the transient computation. The Suliciu's corona model is extended to simulate the charge–voltage curves with minor loops under the damped oscillation surges. The corona effect is considered by adding a corona current term in the telegraphers' equations. The frequency-dependence effect is also taken into account by using the vector fitting and recursive convolution in the time domain. The computed voltage waveforms are compared with the measured ones to examine the validity of the proposed method. The computed results show that the minor loops have a greater effect on the attenuation and distortion for the damped oscillation surges under negative polarity. [ABSTRACT FROM AUTHOR]

This paper presents simulations of stationary and transient (fault condition) regimes for a three-phase concentric HTS cable with and without a standalone superconducting fault current limiter (SFCL). The stationary study carried out previously to the transient analysis verifies the viability of the proposed cable design. The response of the HTS cable to fault currents by varying the thickness of copper stabilization layers is analyzed. As an option, an SFCL is supposed to be connected in series to the same HTS cable to investigate if and how an SFCL device could protect the HTS cable as well as the power network. Results show that fault currents can be limited by adapting the copper layer thickness of the HTS tapes in the cable, but this may result in too high temperatures in the coolant. Only a carefully designed SFCL device can prevent longer cable outages or even damages in the HTS cable caused by too high temperatures. [ABSTRACT FROM AUTHOR]

Spreading phenomena on networks are essential for the collective dynamics of various natural and technological systems, from information spreading in gene regulatory networks to neural circuits and from epidemics to supply networks experiencing perturbations. Still, how local disturbances spread across networks is not yet quantitatively understood. Here, we analyze generic spreading dynamics in deterministic network dynamical systems close to a given operating point. Standard dynamical systems' theory does not explicitly provide measures for arrival times and amplitudes of a transient spreading signal because it focuses on invariant sets, invariant measures, and other quantities less relevant for transient behavior. We here change the perspective and introduce formal expectation values for deterministic dynamics to work out a theory explicitly quantifying when and how strongly a perturbation initiated at one unit of a network impacts any other. The theory provides explicit timing and amplitude information as a function of the relative position of initially perturbed and responding unit as well as depending on the entire network topology. [ABSTRACT FROM AUTHOR]

An analytical model based on the equivalent circuit method is presented to predict the electromagnetic shielding effectiveness (SE) of perforated metallic rectangular enclosure with external waveguide. In this model, the electrically small aperture is represented by a four-terminal network, and the external waveguide and enclosure are modeled as transmission line. By this way, the SE of any position of the enclosure under planewave illumination can be calculated fast and accurately over a wide frequency range (0 ~ 3 GHz). Simulation results of the proposed model are in accord with that of the transmission line matrix method, which verifies the accuracy and reliability of the model. The shielding characteristics of the perforated enclosure with external waveguide are also analyzed. The effects of parameters of aperture position, observation point position, and external waveguide length are discussed in detail. Simulation results show that the external waveguide can effectively improve the SE of the enclosure with aperture. What’s more, the shielding performance of perforated enclosure with external waveguide outperforms the perforated double-layer enclosure in some cases. For a certain length of the waveguide, the longer the edge of aperture which is perpendicular to the direction of the electric field is, the worse the shielding effect of the external waveguide on the enclosure becomes. The SE of the enclosure increases with increase of the length of the external waveguide. [ABSTRACT FROM AUTHOR]

The magnitude of very fast transients (VFTs) generated in disconnector operation in gas-insulated substation (GIS) is mainly determined by breakdown voltage between stationary and movable contacts. Moreover, the initial phase angle of source voltage and the movable contact operation velocity of disconnector are two important factors of affecting the breakdown voltage. The combination of initial phase angle and contact velocity to suppress VFTs is theoretically studied. With 3-D electrostatic simulation model, the capacitance parameters are calculated at different separations between stationary and movable contacts. Taking measured relation between the breakdown voltage and the separation of contacts as criterion, VFTs can be analyzed under different combination of initial phase angle and movable contact velocity. The effectiveness of the method is verified by comparing with experimental data. Based on this method, the effect of initial phase angle, movable contact velocity, and residual charge on repeated breakdown voltage in GIS is discussed and analyzed, and the optimum phase angle for closing and opening operations are selected. The very fast transient over voltage is remarkably suppressed with selection of optimum initial phase angle when disconnect is operated under enough fast velocity of movable contact. [ABSTRACT FROM AUTHOR]

Helicopter transient electromagnetic (TEM) method is a kind of common geophysical prospecting method, widely used in mineral detection, underground water exploration and environment investigation. In order to develop an efficient helicopter TEM system, it is necessary to analyze and optimize the system parameters. In this paper, a simple and quantitative method is proposed to analyze the system parameters, such as waveform, power, base frequency, measured field and sampling time. A wire loop model is used to define a comprehensive ‘time constant domain’ that shows a range of time constant, analogous to a range of conductance, after which the characteristics of the system parameters in this domain is obtained. It is found that the distortion caused by the transmitting base frequency is less than 5% when the ratio of the transmitting period to the target time constant is greater than 6. When the sampling time window is less than the target time constant, the distortion caused by the sampling time window is less than 5%. According to this method, a helicopter TEM system, called CASHTEM, is designed, and flight test has been carried out in the known mining area. The test results show that the system has good detection performance, verifying the effectiveness of the method. [ABSTRACT FROM AUTHOR]

Presents the table of contents for this issue of the publication. [ABSTRACT FROM PUBLISHER]

This study develops and compares several networked control and estimation algorithms to manipulate the power consumption of a population of residential thermostatically controlled loads (TCLs) to fulfill PJM frequency regulation requests given an imperfect communication network and modeling error. The algorithms rely on a model of the plant to reduce the effects of communication delays, and include a stochastic, predictive controller and two Kalman filter-based state estimation techniques. The first estimator uses a set of independent Kalman filters that run in parallel, and the second incorporates individual TCL models that rely on identified thermal parameters. We use simulations to examine 1) the algorithms’ ability to adequately provide frequency regulation under a range of delay severities, and 2) the effect of increased modeling error. We find that both estimator–controller combinations provide acceptable frequency regulation with average delays of 20 s and minor modeling error. When we increase the modeling error by using a higher order model to represent the TCLs within the plant, the first estimator provides acceptable frequency regulation, whereas the second estimator provides poor frequency regulation. [ABSTRACT FROM PUBLISHER]

The ability to manage loads can play a significant role in the future operation and planning of electricity networks. One way of unlocking this source of flexibility without directly involving thousands or millions of customers is to exploit the positive correlation between supplied voltage and demand, i.e., voltage-led load management. Distribution network operators, in particular, could achieve this by adequately controlling voltage regulation devices. Nonetheless, to quantify this it is key to understand the extent to which voltages can be changed (reduced) while considering the dependencies across different voltage levels. A methodology is proposed here to quantify the aggregated demand reduction unlocked by controlling primary substations considering the voltage interactions and constraints throughout the whole distribution network. Given the complexity and dimensions, the influence of the upstream network on primary substations and the effects on low voltage customers are analyzed separately whilst maintaining their dependencies. The methodology, developed within the largest UK load management trial, is applied to real 132 to 0.4 kV distribution networks adopting realistic load models. Results demonstrate not only the significance of the scheme as a source of flexibility but, crucially, that the interactions and constraints across voltage levels are key in its adequate time-varying quantification. [ABSTRACT FROM PUBLISHER]

Smooth running and rapid response are the desired performance goals for the transient motions of servo mechanisms. Because of the uncertain and unobservable transient behaviour of servo mechanisms, it is difficult to evaluate their transient performance. Under the effects of electromechanical coupling, the stator current signals of a permanent-magnet synchronous motor (PMSM) potentially contain the performance information regarding servo mechanisms in use. In this paper, a novel method based on analysing the stator current of the PMSM is proposed for quantifying the transient performance. First, a vector control model is constructed to simulate the stator current behaviour in the transient processes of consecutive speed changes, consecutive load changes, and intermittent start-stops. It is discovered that the amplitude and frequency of the stator current are modulated by the transient load torque and motor speed, respectively. The stator currents under different performance conditions are also simulated and compared. Then, the stator current is processed using a local means decomposition (LMD) algorithm to extract the instantaneous amplitude and instantaneous frequency. The sample entropy of the instantaneous amplitude, which reflects the complexity of the load torque variation, is calculated as a performance indicator of smooth running. The peak-to-peak value of the instantaneous frequency, which defines the range of the motor speed variation, is set as a performance indicator of rapid response. The proposed method is applied to both simulated data in an intermittent start-stops process and experimental data measured for a batch of servo turrets for turning lathes. The results show that the performance evaluations agree with the actual performance. [ABSTRACT FROM AUTHOR]