Line Parameters Research Articles

Real-Time Monitoring of Cable Sag and Overhead Power Line Parameters Based on a Distributed Sensor Network and Implementation in a Web Server and IoT.

Based on the need for real-time sag monitoring of Overhead Power Lines (OPL) for electricity transmission, this article presents the implementation of a hardware and software system for online monitoring of OPL cables. The mathematical model based on differential equations and the methods of algorithmic calculation of OPL cable sag are presented. Considering that, based on the mathematical model presented, the calculation of cable sag can be done in different ways depending on the sensors used, and the presented application uses a variety of sensors. Therefore, a direct calculation is made using one of the different methods. Subsequently, the verification relations are highlighted directly, and in return, the calculation by the alternative method, which uses another group of sensors, generates both a verification of the calculation and the functionality of the sensors, thus obtaining a defect observer of the sensors. The hardware architecture of the OPL cable online monitoring application is presented, together with the main characteristics of the sensors and communication equipment used. The configurations required to transmit data using the ModBUS and ZigBee protocols are also presented. The main software modules of the OPL cable condition monitoring application are described, which ensure the monitoring of the main parameters of the power line and the visualisation of the results both on the electricity provider's intranet using a web server and MySQL database, and on the Internet using an Internet of Things (IoT) server. This categorisation of the data visualisation mode is done in such a way as to ensure a high level of cyber security. Also, the global accuracy of the entire OPL cable sag calculus system is estimated at 0.1%. Starting from the mathematical model of the OPL cable sag calculation, it goes through the stages of creating such a monitoring system, from the numerical simulations carried out using Matlab to the real-time implementation of this monitoring application using Laboratory Virtual Instrument Engineering Workbench (LabVIEW).

Architecture Research on Differentiated Lightning Protection of Distribution Network Considering Plateau Microtopography

Abstract Lightning is the main and severe threat to 10kV and 35kV medium-voltage distribution networks. It will cause equipment failures or damage, tripping and even power outages. With the construction of modern distribution networks, the requirements for power supply reliability are getting higher and higher. Therefore, lightning protection of distribution networks has received great attention. The key point is to find a cost-effective way to protect against lightning. This paper proposed an architecture for differentiated lightning protection of distribution networks considering plateau micro-topography. The main idea is to take multiple measures to obtain rich data, including a lightning positioning system, 3D laser scanning and digital elevation model. Differences in lightning parameters, line and tower parameters, topographic parameters are thought to bring different lightning tripping rates for each tower. Then tripping rate of each area element is obtained through meshing and discrete calculation. Total tripping rate is finally obtained by summation of all elements. The proposed architecture plans to provide a clue for differentiated lightning protection for the distribution network.

A recommended line list for water vapor in the 12,969–13,418cm-1 interval

We have recently devoted two reports to the very weak absorption spectrum of water vapor in the 12,969 – 13,417 cm-1 region by high sensitivity cavity ring down spectroscopy (CRDS) [Vasilchenko et al. J. Quant. Spectrosc. Radiat. Transfer 275 (2021) 107,847; doi.org/10.1016/j.jqsrt.2021.107847; Vasilchenko et al. Molecular Physics e2051762; doi.org/10.1080/00,268,976.2022.2051762]. This spectral interval is important because it includes the region of the oxygen A-band near 760 nm. The achieved sensitivity allowed us to measure lines with intensity on the order of 10–29 cm molecule-1, about two orders of magnitude lower than the detectivity threshold of previous studies. A total of about 240 energy levels of H216O were newly determined. Our comparison to the W2020 empirical levels [Furtenbacher et al. J. Phys. Chem. Ref. Data 49 (2020) 043,103; doi.org/10.1063/5.0030680] led us to identify and correct about 300 W2020 energy levels of the main isotopologue differing from our energy value by more than 5 × 10–3 cm-1. In the present contribution, we consider in details the sources of the W2020 energy levels to identify the origin of these deviations. We confirm that more than 260 energy levels should be corrected but for the remaining thirty-two levels, the W2020 energy values are in fact, more reliable. As a result, we propose an improved list of energy levels retrieved from the CRDS data and a recommended line list for water vapor in natural isotopic abundance in the 12,969 – 13,417 cm-1 region, mostly based on the CRDS line parameters.

Novel traveling wave fault location method for HVDC transmission line based on wavefront frequency

The key of traveling wave (TW) fault location (FL) method is the calculation of TW velocity and the calibration of TW wave head. In order to achieve high-precision FL, detailed transmission line (TL) parameters are needed to accurately calculate the TW velocity. In view of the problem that the existing high-precision TWFL methods are highly dependent on the calculation of TW velocity, the paper contributes to following aspects: (i) the mapping relationship between wavefront frequency and fault distance/fault pole is constructed; (ii) a neural network model suitable for FL and fault pole identification is designed, which is optimized by Particle Swarm Optimization (PSO) algorithm and Levenberg–Marquardt (L-M) algorithm; (iii) a complete FL scheme is proposed. In order to verify the FL accuracy of proposed method, an ±800 kV bipolar high-voltage direct-current (HVDC) transmission system model is constructed using PSCAD/EMTDC. According to the simulation results, the errors of FL is less than 0.2 km and the accuracy of fault pole identification is 100%. For the problems of fault type, fault resistance and noise, the proposed method shows high robustness.

Backward–forward sweep inverse power flow for distribution line parameters estimation with metering data

AbstractThe transition towards the smart grid requires better information on the electrical networks at the distribution system level. Information about electrical line parameters is a critical part of such information. An algorithm for estimating electric line parameters of medium‐voltage distribution networks is proposed. The algorithm relies upon active/reactive power and nodal voltage magnitude data from advanced metering infrastructure and combines an Ordinary Least Squares estimator with the classical Backward–Forward Sweep load‐flow method to iteratively estimate the admittance parameters of the electrical network components. The algorithm is proposed to be applied to balanced loading situations of networks where zero‐injection non‐monitored nodes may exist. Simulations using the IEEE 33‐bus system are used to demonstrate the effectiveness of the method under different loading situations and measurement noise levels.

A novel high-sensitivity time-domain current differential protection scheme for renewable power transmission system

Integrating large-scale renewable energy sources in modern power systems has altered fault characteristics, resulting in the performance degradation of conventional current differential protection. This paper proposes a novel high-sensitivity time-domain current differential protection scheme. The proposed scheme utilizes the Bergeron model to eliminate the impact of the distributed capacitive current. Furthermore, the Bergeron model error is analyzed theoretically during normal operation, and an algorithm is designed to identify and adjust the α- and β-mode line parameters. Additionally, novel internal fault criteria are presented to mitigate the negative impact of the 0-mode line parameter error. Compared to traditional frequency-domain approaches, the proposed method can more accurately and rapidly distinguish internal and external faults, while reducing the dependency on precise line parameters. Eventually, a VSC-HVDC sending-end grid model consisting of 100% renewable power generations is established using PSCAD/EMTDC software. Simulation results confirm that the proposed protection scheme exhibits exceptional performance in terms of operating speed, sensitivity, and tolerance to fault resistance and noise.

Mechanistic aspect of copper selenide as an electrocatalyst for the detection of hydrogen peroxide in gaseous phase

The electrocatalytic properties of copper selenide for hydrogen peroxide detection in a gas phase were investigated using cyclic and square-wave voltammetry. Copper selenide demonstrated significant electrocatalytic activity towards hydrogen peroxide oxidation in a basic medium containing polyacrylic acid as a gas-absorbing polyelectrolyte. Experimental data were corroborated by a brief theoretical analysis and simulations based on a two-electron irreversible electrode mechanism of a dissolved redox couple. The voltammetric response of a conventional glassy carbon electrode modified with copper selenide showed a linear correlation with hydrogen peroxide concentration over a range of 3.0 × 10−5 to 1.0 × 10−3 mol L−1 in solution.Practical application of this method for gaseous hydrogen peroxide detection was explored using screen-printed electrodes (SPE) coated with a thin film of polyacrylic acid containing medium, with copper selenide serving as a modifier of the working electrode. The detectable concentration range of gaseous hydrogen peroxide using the modified SPE spanned picomolar concentrations. The statistical parameters of the calibration line in terms of LOQ, LOD and R2 are 4.1 × 10−6, 1.2 × 10−6 mol L−1, and 0.996, which correspond very closely to the gas concentrations of 6.1 × 10−12 to 6.1 × 10−11 mol L−1.

Intelligent identification of power grid parameters based on dynamic weighting

Transmission line parameter identification plays a crucial role in power systems. However, existing methods for identifying transmission line parameters face several challenges: (1) when dealing with non-Euclidean data such as power grid data, a considerable amount of noise is introduced, (2) inability to treat the power grid as a global system, limiting calculations to individual transmission lines and overlooking inter-branch correlations, (3) high sensitivity to data contamination. To address these issues, this paper proposes a multi-task noisy graph attention network (MNGAN) for power grid parameter identification, which leverages the spatial structure of the power grid and considers the inter-branch correlations. By computing the homogeneity and average degree of the graph data, we introduce an adaptive attention mechanism to the model. This attention mechanism dynamically adjusts the model’s focus on key information, mitigating the impact of data contamination and improving parameter identification accuracy. Additionally, to achieve simultaneous recognition of multiple branch parameters and enhance model training speed and accuracy, we incorporate a multi-task loss function based on homoscedastic uncertainty. Experimental results demonstrate the superiority of our proposed model over other machine learning and deep learning methods, providing more accurate predictions of branch parameters.

NH3 line broadening coefficients and intensities measurement and impurities determination in emerging applications: CCUS, Biomethane and H2

A mid-infrared quantum cascade laser (Mid-IR QCL) coupled with a Single Pass Cell and a Multi Pass Cell, was utilized to measure ammonia (NH3) absorption spectroscopic parameters and determine NH3 impurities toward three emerging applications. We for the first time measured the pressure broadening coefficients perturbed by Air, O2, N2, He, CO2, CH4, and H2 and the line intensities of six NH3 transition lines near 1084.6 cm−1. The measured NH3-He, NH3-Air, and NH3-CO2 broadening coefficients align with HITRAN database, while NH3-H2 coefficients exhibit a maximum discrepancy of 46 %. Deviations between the measured line intensities and HITRAN database are minimal. Nevertheless, the uncertainties of line intensities have been significantly reduced from 20 % in HITRAN to below 3 %. The newly measured line parameters are utilized to address NH3 impurity requirements outlined in CCUS (ISO 27913:2016), Biomethane (EN 16723:2016), and H2 (ISO 14687:2019) standards. Based on the concept of optical gas standard (OGS), the NH3 impurity detection requirements in all three standards have been fulfilled with an uncertainty of 1.35 %. The precision of the NH3-OGS is 800 part per trillion (ppt) with an integration time of 100 s. The repeatability of the NH3-OGS is 130 ppt for a continuous measurement time of 48 min. Notably, the NH3-OGS effectively addresses the highly nonlinear adsorption–desorption dynamics, underscoring the potential of OGS as a calibration-free and SI-traceable metrological gas analysis instrument.

Evaluation of the performance characteristics of a new chemical sensor, device, or method

For those of us involved in the design of novel sensors and methods, understanding the analytical requirements based upon their intended use is essential. In the case of a medical sensor, we must know how the results of a test, performed with the novel sensor, will increase the probability of a good diagnostic or disease management decisions by a physician. So, to assess whether the new sensor meets the expectations, one must design and execute experiments and analyze the results by appropriate statistical methods. As a last step of the evaluation of a novel sensor, one can measure the agreement between the results provided by an established method and the new sensor in a method comparison study. However, the correct statistical approach in method comparison studies is not obvious. In this paper a new evaluation method for determining the unbiased parameters of the association between the compared methods is discussed. It is based on the relationship between the slope and intercept of the regression line in the scatter plot and the parameters of the regression line in the Bland and Altman plot of the differences, in which the differences between the values measured by the compared methods in the same samples are plotted as a function of the average of the measured values. Moreover, we suggest a graphical representation of the data for assessing both the association and the agreement between the compared methods and show the limits of the proposed evaluation method theoretically and using computer-generated data and real-world examples.

Noise-like-Signal-Based Sub-Synchronous Oscillation Prediction for a Wind Farm with Doubly-Fed Induction Generators

The DFIG-based wind farm faces sub-synchronous oscillation (SSO) when it is integrated with a series-compensated transmission system. The equivalent SSO damping is influenced by both wind speed and compensation level. However, it is hard for the wind farm to obtain a compensation level in time to predict the SSO risk. In this paper, an SSO risk prediction method for a DFIG wind farm is proposed based on the characteristics identified from noise-like signals. First, SSO-related parameters are analyzed. Then, the potential SSO frequency and damping are identified from signals at normal working points by integration using variational mode decomposition and Prony analysis. Finally, a fuzzy inference system is established to predict the SSO risk of a DFIG wind farm. The effectiveness of the proposed method is verified by simulation. The proposed prediction method can predict SSO risks caused by the variation in wind speed, while the transmission line parameters are undetectable for the wind farm.

Prediction of ultimate tensions in mooring lines for a floating offshore wind turbine considering extreme gusts

The design of mooring line parameter for a floating offshore wind turbine (FOWT) should consider the ultimate limit state. Typhoons should be considered as a threatening condition for mooring design, and the characteristics of transient changing wind should be studied. Currently, few extreme value predictions consider gust features, and extreme mooring tensions may be underestimated in practical FOWT design. We conducted the simulations of the 5 MW wind turbine from the National Renewable Energy Laboratory (NREL) in the environmental conditions of extreme gusts, waves, and currents. Extreme gusts were found to cause dramatic increases in mooring tensions under 100-year typhoon conditions. The average conditional exceedance rate (ACER) method is used to predict extreme mooring tensions. The impacts of simulation duration and sample size on the prediction results are then discussed. The results show that in extreme gust conditions, the tail data of the average conditional exceedance rate of mooring tension presents a different extrapolation trend from stable wind conditions. Short-term predicted values in gust conditions are 14–20% larger than those in stable wind conditions. The research shows the necessity of considering threatening gust conditions in the ultimate limit state design of mooring system of FOWT.

Identification Method of Transmission Line Parameters Considering Impact of Electro Thermal Coupling Effect

Abstract Studies for high voltage power networks generally ignore line resistance with the assumption of being far less than line reactance. However, this treatment could cause certain errors in analysing low-voltage distributed networks, causing the assumption to no longer be applicable. Such errors could be significant considering the impact of load carrying and ambient conditions, such as online resistance or temperature due to electro-thermal coupling (ETC). Then, it becomes an open question to accurately capture the system state of distribution networks due to changed line parameters. Integrating new style energy sources, such as renewable power generation, energy storage applications, and adjustable power load, will promote the deployment of measurement devices at distribution networks. With the assumption of sufficient accumulated data offered by online monitoring terminals, this study proposes a nonlinear regression method—Levenberg-Marquardt—to identify the parameters of the line. However, since it is difficult to access practical data, this study employs the electro-thermal coupling power flow (ETCPF) to simulate line operation and take the results as monitoring data for case studies. The identification results under various data volumes and error levels demonstrate the reliability and accuracy of the proposed approach.

Simulation Analysis of Corona Pulse Propagation along the Line Based on an Actual Transmission Line

Abstract In the partial discharge test of the shunt reactor of the ultra-high voltage transmission line, the corona discharge caused by high voltage interferes with the test. To further study the propagation rules of the corona pulse on the line side in the transmission line during the ultra-high voltage partial discharge test, based on the parameters of an actual transmission line, the ATP-EMTP electromagnetic simulation software was used for modeling. The propagation rules of corona pulses in the transmission line were analyzed in detail through the simulation model. As the propagation distance increases, different frequency components show different degrees of attenuation. The higher the frequency is, the faster it attenuates.

An in-depth analysis of the variable cyclotron lines in GX 301−2

Context. The high-mass X-ray binary system GX 301−2 is a persistent source with a well-known variable cyclotron line centered at 35 keV. Recently, a second cyclotron line at 50 keV has been reported with a presumably different behavior than the 35 keV line. Aims. We investigate the presence of the newly discovered cyclotron line in the phase-averaged and phase-resolved spectra at higher luminosities than before. We further aim to determine the pulse-phase variability of both lines. Methods. We analyze a NuSTAR observation of GX 301−2 covering the pre-periastron flare, where the source luminosity reached its peak of ∼4 × 1037 erg s−1 in the 5–50 keV range. We analyze the phase-averaged spectra in the NuSTAR energy range from 3.5–79 keV for both the complete observation and three time segments of it. We further analyze the phase-resolved spectra and the pulse-phase variability of continuum and cyclotron line parameters. Results. We confirm that the description of the phase-averaged spectrum requires a second absorption feature at 51.5−1.0+1.1 keV besides the established line at 35 keV. The statistical significance of this feature in the phase-averaged spectrum is > 99.999%. We further find that the 50 keV cyclotron line is present in three out of the eight phase bins. Conclusions. Based on the results of our analysis, we confirm that the detected absorption feature is very likely to be a cyclotron line. We discuss a variety of physical scenarios that could explain the proposed anharmonicity, but also outline circumstances under which the lines are harmonically related. We further present the cyclotron line history of GX 301−2 and evaluate concordance among each other. We also discuss an alternative spectral model including cyclotron line emission wings.

Globin: A spectropolarimetric inversion code for the coupled inference of atomic line parameters

Context. The reliability of physical parameters describing the solar atmosphere inferred from observed spectral line profiles depends on the accuracy of the involved atomic parameters. For many transitions, atomic data, such as the oscillator strength (log(gf)) and the central wavelength of the line, are poorly constrained or even unknown. Aims. We present and test a new inversion method that infers atomic line parameters and the height stratification of the atmospheric parameters from spatially resolved spectropolarimetric observations of the Sun. This method is implemented in the new inversion code globin. Methods. The new method employs a global minimization algorithm enabling the coupling of inversion parameters common to all pixels, such as the atomic parameters of the observed spectral lines. At the same time, it permits the optimum atmospheric parameters to be retrieved individually for each spatial pixel. The uniqueness of this method lies in its ability to retrieve reliable atomic parameters even for heavily blended spectral lines. We tested the method by applying it to a set of 18 blended spectral lines between 4015 Å and 4017 Å, synthesized from a 3D magnetohydrodynamic simulation containing a sunspot and the quiet Sun region around it. The results were then compared with a previously used inversion method where atomic parameters were determined for every pixel independently (pixel-by-pixel method). For the same spectral region, we also inferred the atomic parameters from the synthesized spatially averaged disc-centre spectrum of the quiet-sun. Results. The new method was able to retrieve the log(gf) values of all lines to an accuracy of 0.004 dex, while the pixel-by-pixel method retrieved the same parameter to an accuracy of only 0.025 dex. The largest differences between the two methods are evident for the heavily blended lines, with the former method performing better than the latter. In addition, the new method is also able to infer reliable atmospheric parameters in all the inverted pixels by successfully disentangling the degeneracies between the atomic and atmospheric parameters. Conclusions. The new method is well suited for the reliable determination of both atomic and atmospheric parameters and works well on all spectral lines, including those that are weak and/or severely blended. This is of high relevance, especially for the analysis of observations of spectral regions with a very high density of spectral lines. An example includes the future near-ultraviolet spectropolarimetric observations of the SUNRISE III stratospheric balloon mission.

Control Charts for a Novel Exponent Power Rayleigh Distribution

Abstract: In this Paper, we presented the distribution as A Novel Exponent Power Rayleigh (NovEPRD) probability density function, Distribution, and Survival and Hazard functions introduced by Bharathi et al (2022) and A Novel Exponent Power Rayleigh (NovEPR) distribution Properties and its Applications studied by Bharathi et al (2022) and then here we derived the Weighted Variance (WV), Weighted Standard Deviation (WSD) and Correction Factor (CF) for existed A Novel Exponent Power Rayleigh (NovEPR) distribution , this paper obtains the parameters of the control lines X̅ and R drawn from the A Novel Exponent Power Rayleigh (NovEPR) distribution. These methods are compared with Newton Raphson’s simulations. For these control charts, Type I risk is compared with different groups of A Novel Exponent Power Rayleigh (NovEPR) distribution. Simulation results show that the Skewness Correction (SC) method of Type I carries less risk than other methods. When the distribution is approximately equal, the type I risk of the Shewhart, W V, WSD and SC X̅ plans is comparable, while the type I risk of the SC R plan is smaller

Investigating the sensitivity of dual-phase steel microstructure to continuous annealing line parameters

The mechanical properties of dual-phase (DP) steels are influenced by ferrite grain size, martensite distribution/morphology, and strength differences between ferrite/martensite phases. A sensitivity study was conducted on a continuous annealing line cycle of DP steel manufacturing process to understand the effect of individual segments on the final microstructural features. From the study results, an optimised cycle was developed to obtain a DP steel microstructure with reduced martensite banding, fine ferrite grain size and less untempered martensite. The main modifications are austenite soaking temperature above Ac3 temperature, higher cooling rate of the slow cooling stage, increased soak time at ferrite soaking temperature, and higher over-aging temperature. The optimised cycle produced DP steel microstructure with reduced martensite banding at a similar phase fraction (35%) and decreased ferrite grain size from 8.4 to 5.1 µm. This improved the mechanical properties, increasing tensile strength from 789 ± 21 to 831 ± 14 MPa and total elongation from 15 ± 3 to 20 ± 2%.

Enhancement of transmission line parameters for the supply of energy in the Rivers state local government area of Obio Akpor

Efficient energy transmission is crucial for meeting the growing demand for electricity, particularly in urban and rural areas. In the Rivers State Local Government Area of Obio Akpor, Nigeria, ensuring reliable power supply is essential for supporting economic development and improving quality of life. However, challenges such as transmission line losses, voltage fluctuations, and inadequate infrastructure hinder the effective distribution of energy in the region. This article presents a comprehensive study on enhancing transmission line parameters to improve energy supply in Obio Akpor. Through field measurements, data analysis, and simulation studies, the performance of existing transmission lines is evaluated, and strategies for enhancing efficiency and reliability are proposed. The literature review explores previous research on transmission line optimization, emphasizing factors such as conductor material, line design, and insulation to minimize losses and maximize power transfer capability. Materials and methods encompass data collection, including impedance measurements, voltage profiles, and load characteristics, followed by computer simulations to assess proposed enhancements.

Analysis of heating defects in extension rods of extra-high voltage direct current overhead transmission lines

This paper studies the overheating defect of an extension rod in a ± 800 kV extra-high voltage direct current overhead transmission line, and proposes various factors that affect the overheating of the extension rod. Establish an equivalent model of an extra high voltage DC transmission line based on equipotential point and line parameter analysis, and calculate the model parameters. The proposed model can also be applied to ultra-high voltage DC overhead transmission lines such as ± 500 kV, and has strong universality. Simulation experiments show that if the equivalent resistance value of the split wire side is reduced by 0.01Ω, the power loss on the extension tie rod can be increased to 380.951 W; if the equivalent resistance value of the jumper side is increased by 0.01Ω, the power loss on the extension tie rod can be increased to 273.41 W. Combined with theoretical analysis and simulation verification, it is concluded that the main factor affecting the overheating of the extension rod is the change in the resistance value on the jumper side caused by the increase in contact resistance. A systematic troubleshooting plan for related defect problems is proposed, which has important reference and guidance significance for such line fault problems.