High Voltage Conductor Research Articles

Inhibition characteristics of pollution accumulation in high-voltage direct current conductors with XLPE and PVC film

Abstract The inhibition of pollution accumulation on the ground equipment by cross-linked polyethylene (XLPE) and polyvinyl chloride (PVC) as coating materials was investigated, and the effects of discharge voltage, power supply polarity, and the material properties of ground equipment on the characteristics of dirt accumulation were discussed. When the voltage was greater than 40 kV, the pollution accumulation of the sampling plate of the PVC-coated conductor was higher than that of the XLPE-coated conductor. Whether it was PVC or XLPE coated wire, the amount of pollution accumulation under negative polarity power was greater than that under positive polarity power. When the ground equipment was made of aluminum sheets, the amount of pollution accumulated was greater than that of the PTFE. As the film thickness increased, the amount of pollution on the aluminum fouling film decreased continuously.

Characterisation of the damping performance of a Stockbridge damper from laboratory tests of an overhead high-voltage transmission line conductor

Characterisation of the damping performance of a Stockbridge damper from laboratory tests of an overhead high-voltage transmission line conductor

Insight on the recent materials advances for manufacturing of high-voltage transmission conductors

AbstractTransmission conductor forms the essential pathway where electric power traverses from the generating centre station to the distribution sub-station. Some glitches in power delivery have been attributed to that occasioned by defective transmission conductors. Challenges accruing from transmission conductors can be handled proactively by designing and developing robust conductors. This review was aimed at studying the challenges witnessed in power transmission, ways of ameliorating them, and prospective conductors for future power transmission. In the study, it was observed that lightning, bush fire, short-circuiting, and grid overload are some of the challenges in the transmission grid. It was also observed that aluminium conductor composite core (ACCC) and aluminium conductor composite reinforced (ACCR) are the two best transmission conductors existing presently based on ampacity and efficiency. It was concluded that Al-based composites of CNTs, graphene, BN, Si3N4, and TiC could perform more favourably than the existing transmission conductors. It was recommended that these new materials should be studied further to verify their applicability in transmitting electric power.

An Iterative Graph-Based Method for Constructing Gaps in High-Voltage Bundle Conductors Using Airborne LiDAR Point Cloud Data

An Iterative Graph-Based Method for Constructing Gaps in High-Voltage Bundle Conductors Using Airborne LiDAR Point Cloud Data

Automated monitoring of high-voltage transmission lines based on machine vision

Abstract This paper takes the automated monitoring of high-voltage transmission lines as the entry point and constructs an automated monitoring model of high-voltage transmission lines based on machine vision. Through the transmission equipment recognition algorithm to identify the type and location of the equipment in the inspection image, using image processing methods for the collected high-voltage transmission line image color image grayscaling and grayscale image stretching, and then grayscale image smoothing and segmentation, so as to achieve the identification of the location of high-voltage transmission line fault location. Simulation test for image processing and transmission equipment identification methods, and then carry out automated monitoring experiments with high-voltage transmission line conductor stranding as an example to verify the feasibility and reliability of the model in this paper. The results show that for the automatic detection of individual conductor strand breakage, the method of this paper detects the number of strand breakage is only 1-2 less or more than the actual number of strand breakage; there is a certain difference, but basically in line with the actual situation, and the method of this paper, on average, detects the efficiency of the method is faster than the traditional method by 5.69~7.18 s/m. The research to enhance the quality of automated monitoring of high-voltage power transmission lines has a certain application value.

Fault Analysis of 35kV Outdoor Vacuum Circuit Breaker Pillar Porcelain Sleeve

In order to further clarify the failure mechanism of the pillar porcelain insulator, the field inspection, the microscopic morphology analysis and material analysis of the ceramic shell of the pillar under a 35kV outdoor vacuum circuit breaker were carried out. The results show that the direct cause of the failure is the discharge between the high voltage conductor inside the porcelain sleeve and the weak part of the porcelain sleeve, and the high temperature arc leads to the bursting of the porcelain sleeve. The indirect cause of the failure is the loose porcelain of the porcelain sleeve, the existence of internal layering, uneven composition and micro-pores and other macro and micro defects, and the original defects of the inner surface of the porcelain sleeve, such as local unglazed and poor quality of the porcelain sleeve manufacturing process. In the long-term outdoor operation, the external moisture and gas penetrate into the porcelain sleeve, which leads to the deterioration of the insulation performance of the porcelain sleeve, and eventually leads to failure.

Enhancing the Efficiency of Ice-Resistant Materials in Asphalt Road Surfaces: A Comprehensive Performance Analysis

This study addresses the critical issue of traffic safety in winter, particularly focusing on the challenges posed by ice and snow on roads. Traditional methods of snow and ice removal are often labor-intensive, inefficient, and environmentally harmful. The objective is to develop a more effective solution for asphalt pavement deicing. Inspired by the anti-icing coating technology used in high-voltage conductors, this research develops an ice-suppressing material designed to reduce the adhesion between snow, ice, and pavement surfaces. The material’s performance is evaluated in terms of deicing efficiency, durability, adhesive properties, and its impact on pavement performance. Test results demonstrate that the developed ice-suppressing material significantly reduces the adhesion between the ice layer and the pavement, facilitating easier removal. This study concludes that the developed ice-suppressing material significantly enhances deicing efficiency on asphalt pavements. It exhibits strong hydrophobic properties, as evidenced by increased water droplet contact angles on coated surfaces (99.5° to 83.3°) compared to clean glass slides (39.2° to 29°). This hydrophobicity effectively reduces ice adhesion, decreasing tensile and shear strength of the ice layer by 38.2% and 63.6%, respectively. Additionally, the material demonstrates superior ice-melting capabilities in sub-zero temperatures, with coated ice cubes showing a higher mass reduction rate than uncoated ones. Importantly, its slow-release nature ensures sustained deicing performance over multiple cycles, maintaining effectiveness after seven test cycles. This study introduces an innovative ice-suppressing material that not only improves the efficiency and environmental impact of deicing methods but also contributes to enhancing road safety in winter conditions. The material’s novel composition and sustained effectiveness present a significant advancement in the field of winter road maintenance.

Formation of plasma channel under high-voltage electric pulse and simulation of rock-breaking process

In the context of rock fragmentation, the application of high voltage electric pulses results in the transfer of electrical energy onto the surface of the rock material, leading to a rapid electrical breakdown and the formation of a plasma channel. The ionized plasma expands at a fast velocity, generating a shock wave that causes significant damage to the rock’s integrity. In this study, we develope a numerical model that couples electrical, thermal, and mechanical forces to simulate the formation of plasma channels within rocks due to high-voltage electric pulses. The model’s accuracy is verified through field tests, and the results indicate that the configuration of the high-voltage pulse waveform, electrode spacing, and conductor particles within the rock impact the pathway of plasma channel formation. Prior to the formation of the plasma channel, minimal changes are observed in temperature and stress levels, with the majority of electric pulse energy dedicated to the creation of the plasma channel. Following the establishment of the plasma channel, the application of the electric pulse continues, resulting in notable alterations in temperature and stress levels. When the duration of the action reaches 105 ns, the temperature and stress levels surpass 104 K and 50 MPa, respectively, leading to fracture and extensive damage to the rock. The outcomes derived from the numerical model’s calculations can help to facilitate the cross-integration between physics and civil engineering and contribute to a deeper understanding of the rock fragmentation process under high voltage electric pulses.

Long-term follow-up of patients undergoing add-on pacing/sensing lead vs. ICD lead implantation for failed IS-1/DF-1 ICD leads: a single centre experience

Background Intracardiac defibrillator/cardioverter (ICD) is a cornerstone device for prevention of sudden cardiac death. Lead failure (LF) is one of the most important long-term complications. In this study, we sought to investigate mid-to-long term clinical, device and lead characteristics of patients who have undergone pacing sensing lead (PSL) implantation for an ICD LF and compare them to the patients who have undergone a new ICD lead implantation. Methods In this retrospective, single centre, case-control study, we have screened all ICD patients presenting with LF. Patients with IS-1/DF-1 ICD leads with intact high-voltage conductor were included in the study group, while other patients were included in the control arm. Study group patients underwent PSL implantation, control group patients underwent ICD lead implantation. Results Thirty patients were included in each arm of the study. The mean duration of follow-up after intervention was similar in both groups (47.6 months ± 20.4 vs. 46.1 months ± 25.7, p = .808). The total failure rate was not different between two groups (p = .640). Rate of high-voltage conductor disfunction was also similar between two arms: 1 (3.3%) in PSL arm and 0 in control arm (p = .303). Conclusions Addition of a PSL for IS-1/DF-1 ICD LF with normal high-voltage conductor measurements is a viable treatment option with similar long-term results to addition of a new ICD lead. This approach is potentially less costly, technically less demanding, and, in case of concomitant extraction procedure, associated with less acute complication risk.

Numerical Research of High-Voltage Conductors: Electric Field Characteristics in Ice-Covered Spaces

Numerical Research of High-Voltage Conductors: Electric Field Characteristics in Ice-Covered Spaces

Future projections of wet snow frequency and wet snow load on overhead high voltage conductors over Italy

Heavy snowfalls represent some of the most serious hazard for transmission and distribution grids because they trigger the formation of sleeves on overhead power lines whose loads may cause outages and, consequently, prolonged disruptions of the energy supply. In order to provide useful information in planning and decision making to cope with wet snow impacts and strength the resilience of the Italian transmission network, some future climate projections about the occurrences of wet snow events and the related loads on overhead power lines were elaborated for different 20-year periods until 2100 by using 12 high-resolution Euro-CORDEX models (spatial resolution of ∼12 km) under the two different emission pathways RCP8.5 (without mitigation) and RCP4.5 (with moderate reductions of greenhouse gases emission). In addition, the reanalysis dataset MERIDA OI was used to bias-correct the climate models as well as to implement a methodology aimed to estimate climatic wet snow scenarios, by the use of a wet snow accretion model on power lines. The results were validated comparing them with wet snow loads observed at the Vinadio WILD station (Italy) and with the recorded failures in energy supply during some serious wet snow events occurred in Italy. Referring to Extreme Value Analysis, probability maps of wet snow loads exceeding some infrastructural hazard thresholds were estimated by means of the “Generalized Extreme Values” distributions, assuming a stationary climate in each 20-year period. In order not to have to assume climate stationarity, two new frequency indices were calculated directly from the outputs of the models, and the Wilcoxon test was applied to investigate the statistical significant of the trends, as well the agreement among the models to test the robustness of the results. In both methods the results point out relatively complex patterns of climate change effects: wet snow events will generally decrease in frequency and intensity at medium-low altitude, particularly under RCP8.5 pathway where projections highlight a sharply reduction of the events, as rainfalls will prevail over snowfalls due to global warming. But, by the end of the Century, wet snow events are likely to intensify over high Apennine and Alpine regions so far spared because of their historical cold temperatures. Finally, the evolution of wet snow events was investigated and tested more specifically for some mountain sites.

Balancing wildlife protection and wildfire threat mitigation using a network optimization approach

In boreal forests of North America, land managers often carry out preventive treatments of forest fuel for the protection of human infrastructure from wildfires. However, these treatments may negatively affect other ecosystem services, such as the capacity to sustain wildlife populations. Here, we examine the efficacy of a strategy aimed at preserving a critical movement corridor for boreal woodland caribou (Rangifer tarandus caribou) in northern Québec, Canada, by raising high-voltage power line conductors above the forest canopy. To assess the interplay between the caribou protection objectives and a reduction in power line's exposure to wildfires, we developed an optimization model that combines the objectives of protecting the power line from wildfires via fuel treatments and maintaining a suitable movement corridor for caribou. The model combines a critical node detection (CND) problem with a habitat connectivity problem that allocates a minimum-resistance fixed-width habitat corridor between isolated wildlife refuges. Our results identify the best locations to perform fire fuel treatments to lessen the threat of fire damage to human infrastructure while maintaining a connectivity corridor for caribou in present and future climate scenarios. The selected fuel treatment locations aimed to mitigate wildfire exposure to a power line. In small-budget solutions, the exposure of power line infrastructure to wildfires was reduced by 36–39% in current climate conditions and by 20–31% in future climate, compared with no-treatment scenarios. Despite the detrimental effects of wildfire on both the industrial asset and caribou habitat, the approach provides strategies that help achieve a compromise between these two values. Such knowledge is timely to help mitigate the negative impacts of climate change on human livelihoods and natural ecosystems.

Optimization of painting efficiency applying unique techniques of high-voltage conductors and nitrotherm spray: Developing deep learning models using computational fluid dynamics dataset

The impetus of the current three-dimensional Eulerian–Lagrangian work is to analyze the impact of simultaneously using the inventive high-voltage conductors and Nitrotherm spraying technique for maximizing the industrial painting process efficiency. This investigation employs high-fidelity computational fluid dynamics (CFD) results in deep learning models as an input dataset. The novel conductors are called high-voltage retractable blades (HVRB) and high-voltage adjustable control-ring (HVACR) mounted on the head of the electrostatic rotating bell sprayer. The influence of dominant operational parameters, such as temperature and velocity of injected nitrogen or air, droplets' electric charge values, and their size ranges, and electric field density are examined in the considered database for the Nitrotherm spraying methodology. This broad range of parametric investigation illustrates that the inclusion of shaping nitrogen flow, manipulated electric field density, and droplet charging weights significantly affect the spraying deposition rate. The pressurized clean heated nitrogen flow, which is injected from the nozzles of the atomizers, positively redirects and harmonizes the charged droplets that construct an optimized spray plume pattern with a smaller diameter. Using innovative HVRB and HVACR conductors is manipulated the electric fields and leads to denser distribution, intensifying the acting electric force on the droplets, resulting in higher spraying transfer efficiency (TE) and thicker film formation. Based on the results, employing the introduced conductors in combination with the heated nitrogen instead of air leads to higher TE, rare overspray occurrence, formation of an esthetic paint film, lower paint consumption, and application time. Also, the collected complete database is employed for machine learning investigation to predict flow with high accuracy, aiming to reduce computational time/cost. A convolutional auto-encoder is used to reduce the computational cost with just 10% of the initial CFD computations, with a mean error of 1% on the prediction of the deposited droplet areas of the spray. The analysis revealed that by employing recurrent convolutional layers, superior capturing of the input pattern is obtained, which significantly aids the final prediction.

Physical mechanism of electrode coatings to suppress wire particle’s firefly motion under DC stress and selecting criterion for in situ applications

The Wire metal particles in gas-insulated equipment such as GIS (Gas-Insulated Substation) and GIL (Gas-Insulated transmission lines) under DC stress present a special firefly motion behaviour, namely a long-term levitation on the surface of conductors. However, the electrode coating, as a key device available to suppress the movement of particles, lacks of a theoretical basis as well as an effective selecting criterion to suppress wire particle’s firefly. In this paper, a test platform is established to obtain the charge dynamics and ionic wind characteristics of the wire particles on the coated electrodes. Experimental results illustrate that, the polarity alternation of wire particle charge due to the space charge accumulation near the wire particles as well as the ionic wind generated by the wire particles, is the key impact factor upon firefly motion. The coated electrodes will reduce the surface conduction current and thereby suppress the particle corona discharge, consequently suppressing the firefly motion by limiting the charge acquisition and ionic wind speed of the wire particles. Based on the above research, a selecting criterion of electrode coating material is further proposed. Electrode coatings is primarily expected to increase the corona onset voltage of the wire particles on the coating surface, so as to lower the ionic wind at the end of the particles less than 1 m s−1. Regarding the high voltage conductor, the coating material with relatively large conductivity is recommended, while for the grounded enclosure, the coating material with smaller conductivity is preferable as to constrain the particles adhere to the enclosure, thereby preventing the firefly motion of wire particle. Both the clarified physical mechanism and the proposed selecting criterion of electrode coating presents theoretical and quantitative guidance for DC GIL design from a specific point of view in suppressing the firefly motion.

Particle behavior and trap design for ±320 kV gas-insulated power transmission line (GIL)

The movement of metal particles in the electric field of the DC gas-insulated transmission line (GIL) may cause local electric field distortion on the surface of the spacer, which seriously affects the operation stability of the GIL. In this paper, based on a ±320 kV GIL platform, the movement characteristics of metal particles (aluminum blocks, aluminum wires, aluminum balls) inside the GIL are studied. The suppression effect of particle activity for particle trapping and surface coating are experimentally studied in DC electric field. The relationship between particle trap porosity and particle suppression effect are discussed and verified with experiments. The research results show that under negative voltage, the minimum take-off voltage of metal particles in ±320 kV GIL is −190 kV, which is far lower than the steady-state operating voltage of GIL. Once the spherical and blocky particles take off, they will continue to reciprocate rapidly between the conductors. When the block particles are close to the spacer, they might be attracted and adsorbed on the surface of the spacer. Metal wires after taking off tend to show ‘firefly’ movement near the high-voltage conductor. The coating has a significant effect on increasing the take-off electric field of metal particles. It is verified that the traditional AC GIL particle trap is not effective in inhibiting particles in DC voltage. The suppression of the DC GIL particle is positively related to the porosity of the particle trap to a certain extent. The conclusions of this paper can be reference for the development of future stable and reliable DC gas-insulated equipment.

Rogowski and D-Dot Sensors for Nanosecond High-Voltage and High-Current Pulse Measurements in Impedance-Matched Pulse Generators

To measure the output voltage and current in our impedance-matched solid-state Marx generator we developed a voltage and current sensor integrated with the IMG structure. One of the advantages of our IMG structure is the coaxial inner transmission line (TL). The end of this TL is the output connection, which consists of a grounded ring and a smaller high-voltage (HV) inner conductor (coaxial). This structure is ideal for fitting D-dot and Rogowski-coil sensors, as these sensors can benefit from the strictly defined electric and magnetic fields in this waveguide. We developed D-dot and Rogowski-coil sensors on printed circuit boards (PCB) and show their usability in our application for measuring HV pulses. The sensors have a bandwidth of about 200 MHz, measure voltages up to 20 kV, and currents up to hundreds of amperes. Their simple PCB design makes them easily reproducible and cheap compared to commercial sensors. Although designed for our IMG, they can be fit on any coaxial line. Next, we made passive integrators to partly integrate the differentiated sensor signal, which improves the signal quality when measured with an oscilloscope. Finally, after software signal postprocessing, we achieve far better voltage measurements and similar current measurements compared to commercial probes.

Improved Mechanical Property and Corrosion and Wear Resistance of High-Voltage Aluminium Wires by Micro-Arc Oxidation Coating

New surface treatments are required to improve the resistance of high-voltage aluminium conductors to corrosion and wear. This paper describes the preparation of ceramic coatings on the surface of aluminium wires by the micro-arc oxidation (MAO) technology. The surface morphology, mechanical and tribological properties, electrical resistivity, wear and corrosion resistance of the MAO-treated aluminium samples are examined and compared not only with the untreated samples but also between the use of different current densities in the MAO process. The MAO treatment can increase the tensile strength of the wire and mitigate the wire elongation at excessive high temperature. In addition, the increased surface hardness and the overlapping micro-porous distribution of the MAO coating improve the resistance of the treated sample to wear and corrosion respectively, protecting the aluminium substrate from the joint effects of wear and corrosion. Furthermore, the MAO coating has little impact on the electrical resistivity of aluminium conductors and can mitigate the resistivity change due to corrosive damage. The MAO technology providing a potential idea for the surface treatment of aluminium conductors is expected to extend the service life and alleviate maintenance needs of aluminium conductors operating in harsh environments.

One-Step Synthesis of Three-Dimensional Na3V2(PO4)3/Carbon Frameworks as Promising Sodium-Ion Battery Cathode.

Sodium-ion batteries (SIBs) are essential for large-scale energy storage attributed to the high abundance of sodium. Polyanion Na3V2(PO4)3 (NVP) is a dominant cathode candidate for SIBs because of its high-voltage and sodium superionic conductor (NASICON) framework. However, the electrochemical performance of NVP is hindered by the inherently poor electronic conductivity, especially for extreme fast charging and long-duration cycling. Herein, we develop a facile one-step in-situ polycondensation method to synthesize the three-dimensional (3D) Na3V2(PO4)3/holey-carbon frameworks (NVP@C) by using melamine as carbon source. In this architecture, NVP crystals intergrown with the 3D holey-carbon frameworks provide rapid transport pathways for ion/electron transmission to increase the ultrahigh rate ability and cycle capability. Consequently, the NVP@C cathode possesses a high reversible capacity of 113.9 mAh g-1 at 100 mA g-1 and delivers an outstanding high-rate capability of 75.3 mAh g-1 at 6000 mA g-1. Moreover, it shows that the NVP@C cathode is able to display a volumetric energy density of 54 Wh L-1 at 6000 mA g-1 (31 Wh L-1 for NVP bulk), as well as excellent cycling performance of 65.4 mAh g-1 after 1000 cycles at 2000 mA g-1. Furthermore, the NVP@C exhibits remarkable reversible capabilities of 81.9 mAh g-1 at a current density of 100 mA g-1 and 60.2 mAh g-1 at 1000 mA g-1 even at a low temperature of -15 °C. The structure of porous carbon frameworks combined with single crystal materials by in-situ polycondensation offers general guidelines for the design of sodium, lithium and potassium energy storage materials.

Study on the Lightning Protection Performance for a 110 kV Non-Shield-Wired Overhead Line with Anti-Thunder and Anti-Icing Composite Insulators

Due to micro landforms and climate, the 110 kV transmission lines crossing the mountain areas are exposed to severe icing conditions for both their high voltage (HV) conductors and shield wires during the winter. Ice accumulation on the shield wire causes excessive sag, which leads to a reduced clearance between earth and HV wires, and could eventually result in tripping of the line due to phase-to-ground flashover. Due to the lack of effective de-icing techniques for the shield wires, removing them completely from the existing overhead line (OHL) structure becomes a reasonable solution to prevent icing accidents. Nevertheless, the risk of exposure to lightning strikes increased significantly after the shield wires were removed. In order to cope with this, the anti-thunder and anti-icing composite insulator (AACI) is installed on the OHLs. In this article, the 110 kV transmission line without shield wire is considered. The shielding failure after installation of the AACIs is studied using the lightning strike simulation models established in the ATP software. The lightning stroke flashover tests are carried out to examine the shielding failures on various designs for the AACIs. Assuming the tower’s earth resistance is 30 Ω, the LWL of back flashover and direct flashover are 630.88 kA and 261.33 kA, respectively, after the installation of AACIs on an unearthed OHL. Due to the unique mechanism of the AACI, the operational voltage level and the height of the pylon have a neglectable influence on its lightning withstand level (LWL). When the length of the parallel protective gap increases from 450 mm to 550 mm, the lightning trip-out rate decreases from 0.104 times/100 km·a to 0.014 times/100 km·a, and the drop rate reaches 86.5%. Therefore, increasing the gap distance for the AACI to provide additional clearance is proven to be an effective method to reduce the shielding failure rates for non-shield-wired OHLs.

Ultrasensitive lightweight magnetic probe for non-destructive inspection of high-voltage overhead lines

For power utilities with comprehensive asset management programs, inspection of high-voltage line conductors is critical to ensure network reliability. Current non-destructive testing methods for ferromagnetic materials are still not completely adapted to perform these inspections quickly, safely and accurately. This paper presents the prototype of a novel probe that is specifically designed for the inspection of conductors steel core. It is based on a novel lightweight and symmetrical design intended for automated inspection by drone. The sensitivity of the new probe is achieved by compensating for the conductor’s imperfect centering during inspection and by creating a zero magnetic field point that allows the use of low range and accurate fluxgate sensors. Experimental results verify that the prototype is capable of detecting broken wires, quantifying metal area loss and inspecting steel core splice joints under unsaturated magnetization, which is the key element to achieve a lightweight probe.