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In light of the issues associated with the laying process of transmission line cables, including concealed security risks and contact collisions between pulleys and cables, which primarily stem from reliance on drawings, this paper introduces a simulation methodology for the cable laying construction process utilizing Building Information Modeling (BIM) technology. Initially, two-dimensional DWG graphic data are employed to develop a model of the target equipment and construction environment using BIM software (Solid works 2020). Subsequently, the cable is accurately modeled by applying ADAMS virtual prototype technology, the bushing force connection method, and the macro command language. This allows for the construction of a three-dimensional real cable laying system for transmission lines, enabling the simulation of the dynamic cable laying process in the field. Subsequently, an error analysis is conducted to compare the axial tension and laying speed of the cable with theoretical calculation values. The study then proceeds to analyze tension fluctuations during the cable laying process and assess the load-bearing capacity of the pulleys, thus facilitating effective control of the construction process and enhancing safety measures. The findings indicate that the proposed method can accurately and efficiently simulate the on-site cable laying construction process, with numerical errors maintained below 5%, thereby validating the integrity of the model. Furthermore, the traction overload safety protection amplification coefficient is determined to be α = 1.5. It is highlighted that the bearing capacity of the block must exceed 60% of the load carried by the conductor at constant speed. This research provides a theoretical foundation for addressing safety hazards in cable laying engineering and holds certain engineering value.

The occurrence of tree flash faults in hybrid overhead–underground lines presents a significant challenge to the smooth operation of power systems. However, research on localizing such faults is relatively scarce. This study conducts theoretical analyses on the formation of tree flash faults, constructs a tree flash fault discharge test platform, and simulates the discharge process. The tree flash fault discharge traveling wave signals were obtained through a high-frequency current acquisition system. Additionally, this paper establishes a model for the current traveling wave of tree flash faults and analyzes transmission attenuation. To enhance the bi-terminal traveling wave localization method, we introduce modal decomposition and the Hilbert–Huang transform. Modal decomposition is used to disentangle signals and derive the instantaneous frequencies of modal signal components through the Hilbert–Huang transform. This process helps determine the time at which the initial wavefront reaches the terminals of the mixed-line transmission. The simulation analysis carried out using PSCAD/EMTDC v4.6.3 demonstrates that this method effectively calibrates the wavefront timing of tree flash fault signals without requiring knowledge of their wave velocity along the mixed-line transmission. Therefore, this approach achieves precise localization of tree flash faults efficiently.

This study focuses on the semiconductive silicone rubber of 10 kV cold-shrink accessories. Accelerated thermal aging tests were conducted on the semiconductive silicone rubber, obtaining tensile stress–strain curves at various time points after thermal aging. The corresponding parameters of the Yeoh hyperelastic model were calculated. The results indicate that the initial shear modulus of the samples decreases with the increase in the aging temperature and time. Microscopic morphology, changes in cross-sectional content, thermal residual values, and chemical structure changes of the samples after aging were studied using electron microscopy, EDS testing, TG curves, and Fourier spectra. The results show that the surface roughness of the aged semiconductive silicon rubber increases, the residual values decrease, the thermal stability decreases, the main chain absorbance decreases, the main chain integrity decreases, and the organic functional groups Si-CH3 and Si(CH3)2 decrease, leading to a reduction in organic content.

In this paper, we focus on the numerical solution of the second kind of Volterra integral equation with a highly oscillatory Fourier kernel. Based on the calculation of the modified moments, we propose four collocation methods to solve the equations: direct linear interpolation, direct higher order interpolation, direct Hermite interpolation and piecewise Hermite interpolation. These four methods are simple to construct and can quickly compute highly oscillatory integrals involving Fourier functions. We present the corresponding error analysis and it is easy to see that, in some cases, our proposed method has a fast convergence rate in solving such equations. In some cases, our proposed methods have significant advantages over the existing methods. Some numerical experiments demonstrating the efficiency of the four methods are also presented.

The adequate interfacial pressure of silicone rubber in cable intermediate joints is a basic condition to ensure the normal operation of cable joints, while high temperature and ageing in the operation of actual cables and accessories would affect the magnitude of interfacial pressure. The uniaxial tensile force of two different silicone rubbers for 10 kV cold-shrink joints at different temperatures and thermal ageing times was measured by experiment, and the Yeoh rubber intrinsic structure model was fitted according to the measured data. The material model was embedded into a two-dimensional axisymmetric finite element simulation model of the structure, and the relationship between the interference, temperature, thermal ageing time and interfacial pressure was investigated. The results show that the interfacial pressure increases linearly with the increase in interference. At the same interference, the interfacial pressure at the root of insulating silicone rubber and semiconducting silicone rubber increased by 9.1%, 12.3%, 6.4% and 9.2%, 16.3%, 5.6%, respectively, at 50, 75, and 100 °C compared with room temperature, and the largest interfacial pressure of cable joints was at 75 °C. Using the established ageing life prediction model based on the Arrhenius principle, the service life of the accessories was predicted to be 28.9 years at 90 °C of operating temperature and interfacial pressure greater than 55% of initial interfacial pressure.

Detecting defects in grounded flat steel is essential for ensuring the safety and reliability of transmission tower grounding devices. However, traditional inspection methods, such as physical excavation and verification, are costly and time-consuming. This paper proposes a corrosion defect detection method for flat steel transmission tower grounding devices based on electromagnetic ultrasonic SH waves. In addition, using commercial software, a three-dimensional finite element simulation model of grounded flat steel with simulated pitting corrosion defects is constructed. The specified displacements applied to multiple surface sources mimic the horizontal shear vibrations generated by the electromagnetic ultrasonic transducer on the surface of the grounded flat steel during actual inspection. A simulation was used to investigate the propagation and attenuation characteristics of shear-horizontal ultrasonic SH0guided waves for simulated corrosion defects with various geometric configurations in grounded flat steel. The simulation investigated the propagation and attenuation characteristics of the SH0 wave in grounded flat steel and the detection of various defects for linear analysis of the results. The simulation results show that the attenuation of the electromagnetic ultrasonic guided wave is small, at only 0.0016 dB/mm, and the displacement amplitude of the echo signal decreases with the increase of the SH0 wave propagation distance. Increasing the depth and length of corrosion defects increases the echo signal amplitude. At the same time, the width of corrosion defects has little effect on the echo amplitude. Finally, a flat steel defect detection experiment was conducted, and the experimental results fit with the simulation to verify the accuracy of the simulation model. This detection method introduces a new idea for the on-site detection and quantitative identification of corrosion defects in grounded flat steel, which has significant reference value and can provide a more effective and economical method for ensuring the safety and dependability of transmission tower grounding devices.

The interface pressure between the cable attachment and the body is crucial for the stable long-term operation of the cable. To solve the issue of interface insulation characteristics’ damage caused by the pressure transducer measurement method, a non-destructive testing method of silicone rubber interface pressure using nonlinear ultrasound is presented. Initially, the study analyzes the propagation characteristics of ultrasonic waves at the interface of cross-linked polyethylene and silicone rubber. The study also establishes the relationship between the nonlinear coefficient and the interface pressure. Subsequently, a nonlinear ultrasonic test platform is constructed using the pulse reflection method to measure the interface pressure of flat silicone rubber and cross-linked polyethylene through nonlinear ultrasonic testing. Theoretical and experimental results indicate that the fundamental amplitude of the frequency domain of the interface reflection wave decreases, and the second harmonic amplitude and nonlinear coefficient both increase as pressure increases. These results demonstrate that the nonlinear ultrasound, non-destructive testing method can accurately evaluate the interfacial pressure state of the cable accessories.

To study the influence of the laser power, scanning speed, and cleaning water content on the laser cleaning effect and obtain the best cleaning parameters, this paper conducted a simulation analysis of the laser cleaning process and carried out a pulse laser cleaning of porcelain insulators experiment to verify. The results show that the cleaning rate gradually increases as the laser power increases from 20 W to 25 W. As the scanning speed increases from 1000 mm/s to 2500 mm/s, the laser overlapping rate gradually decreases, and the cleaning takes the lead in increasing and then decreasing. The appropriate cleaning water content is conducive to laser cleaning; when the water content is 0.115 g, the cleaning efficiency reaches the highest value of 98.20%. When the laser power is 25 W, and the scanning speed is 2000 mm/s, the cleaning efficiency can reach the highest value of 96.87%. This paper shows that the reasonable choice of cleaning parameters can effectively clean the insulator surface filth and obtain a better surface morphology.