Studies on the Effects of Environmental Pollution on ACSR Conductors (original) (raw)
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An expert system for condition assessment of ACSR conductors
2011
Energized ACSR conductors of overhead power transmission lines gradually degrade due to the thermal impact and environmental pollution over a long period of time. This paper introduces an expert system designed to diagnose the condition of overhead power conductors. The expert system is able to predict the deterioration level using a fuzzy inference paradigm based on important environmental phenomena including ambient weather conditions and atmospheric pollution. Weather parameters at each tower location of a transmission line were extracted from a weather database. The estimated amount of pollutants at each tower location were derived from the historical data sets of the National Pollutant Release Inventory. Output of the proposed expert system is the spatial distribution of conductor deterioration grades that can be used to predict the remaining life of the energized conductor. Moreover, the spatial nature of this nondestructive diagnostic tool allows its use for better scheduling of line inspections, maintenance, and refurbishment.
Engineering Failure Analysis, 2012
In order to evaluate the damage of the 26-year-old ACSR conductors of the 100 kV Zhu-Xie transmission line in Tongling, Anhui province, China, the conductors across the #11 and #12 towers were studied via morphological observation, metallurgical analysis and individual wire tensile strength (IWTS) test, especially for the conductors under the vibration dampers and the strain clamps. The results show that the outer Al strands of the conductor under the vibration damper and the strain clamp are mainly subject to the scraping damage by the aluminum armour tape and the adhesion/abrasive wear injured by the aluminum armour tape and the other Al strands. As for the inner Al strands, the main damage mechanisms are of the adhesion/abrasive wear and the propagation of the fatigue cracks originated from the wear surface. For the steel core strands, only the zinc coating is partially destroyed, but the steel cores are survived. After 26 years running, the average IWTSs of the outer/inner Al strands decrease more or less, however, the IWTS of the steel core strands is almost not changed. The aged conductors are still in a good condition, but more intensive inspection and maintenance is suggested.
2023 CIGRE Canada Conference & Exhibition Vancouver, BC, Sept.25 – 28, 2023, 2023
ACSR (Aluminium Conductor Steel Reinforced) conductors can be significantly impacted by various factors contributing to conductor deterioration over time, such as corrosion, fatigue, and environmental exposure. Furthermore, elevated temperatures can degrade Al-1350H19 and the steel wires of the conductor mechanically, electrically, and chemically. This can result in a reduction in mechanical strength, an increase in electrical resistance, and changes in the conductivity properties. Temperaturerelated mechanical deterioration can result in creep, thermal fatigue, permanent deformation, and ultimately conductor failure. Increased resistance property is one example of electrical degradation that can decrease electrical system efficiency. A consistent model that describes the geometry and material characteristics of the conductor is needed to study the effects of temperature on the deterioration of the ACSR conductor. This paper proposes an experimental and numerical analysis degradation of aged ACSR CONDOR conductors based on changes in thermal expansion, elastic modulus, and electrical conductivity caused by elevated temperature over a long period. Aged conductor samples used in this investigation were operated for over half a century. By examining the experimental and numerical results, it is possible to understand the effects of high temperatures, such as the change in absorption or emissivity. Several laboratory tests were carried out on a 6-meter-long bench of new and aged ACSR Condor conductors at the Hydro-Quebec test facilities (CRHQ). In a time-stepped range, the current intensity varied from 300 to 1500 Amperes in 300 Amperes increments. To predict the effects of temperature on the degradation of conductors, a Multiphysics finite element model was developed in the software ANSYS, considering the specific materials used in the conductor and their thermal properties, as well as the operating conditions the conductor was subjected to. When the temperature functions of the current-density curves were compared during the validation stage, the numerical results matched the new conductor result data reasonably well. The numerical model was also subjected to a sensitivity analysis of temperature-current density results to assess the impact of reduced conductor model configuration and length, element configuration and sizing, ambient temperature, and convection rate. A pronounced non-linear
Incidence of Corrosion on Electric Power Losses in ACSR Cables
This research performed a marine atmosphere simulation, using a saline fog chamber as a means to generate accelerated corrosion of conducting aluminum with steel reinforcement, used to construct electric power transport networks. The rate of corrosion was determined through the gravimetric method that consisted in measuring the loss of mass taking place in the sample. The experiment was conducted by taking three samples of ACSR (Aluminum with Steel Reinforcement) cable of different gauges, which received a flow of alternate current while the metal was being corroded. Through measuring equipment, electric power consumption was recorded to verify changes in the energy transported, given the exposure of the samples to corrosion. Likewise, voltage and current were measured to determine the system's stability. Results showed that the hours of exposure of the samples in the saline fog chamber generated greater effects in galvanized steel, causing damage to its zinc layer, in contrast to aluminum that turned out to be more resistant to this type of contaminant. Also, the electric power losses registered were not significant; possibly due to the sample's exposure and energizing times. Resumen En la presente investigación se realizó una simulación de atmosfera marina, utilizando la cámara de niebla salina como medio para generar la corrosión acelerada del conductor de Aluminio con refuerzo de acero, el cual es utilizado en la construcción de redes de transporte de energía eléctrica. La velocidad de corrosión se determinó por el método de gravimetría que consistió en la medición de la pérdida de masa que presentó la probeta. El experimento se hizo tomando tres probetas de cable ACSR de diferente calibre, al cual se le aplicó un flujo de corriente alterna mientras se corroía el metal. Mediante un equipo de medida se registró el consumo de energía eléctrica para verificar la presencia de cambios en la energía transportada, debido a la exposición de las muestras a la corrosión. De igual manera la tensión y la corriente se midieron para determinar la estabilidad del sistema. El resultado mostró que las horas de exposición de las probetas en la cámara de niebla salina generaron mayor afectación en el acero galvanizado causando daño en su capa de zinc, al contrario del aluminio que mostró ser más resistente a este tipo de contaminante. Así mismo las pérdidas de energía eléctrica registradas no fueron significativas debido posiblemente al tiempo de energización y de exposición de las probetas.
Corrosion detection in steel reinforced aluminium conductor cables
2014 Australasian Universities Power Engineering Conference (AUPEC), 2014
Aluminum Conductor Steel Reinforced (ACSR) cables, as part of transmission lines, are used in severe environments in coastal areas and industrial zones for many years. These cables are affected by galvanic corrosion in the interface between the aluminum and steel strands. This paper investigates the existing methods of corrosion detection used in ACSR cables of overhead transmission lines, and estimates the location of corrosion through simulation in a computer program. The paper also analyses two promising methods of corrosion detection, namely "electromagnetic induction" and "time domain reflectometry (TDR)", and explains in detail their principle of operation and efficiency. The paper then thoroughly investigates the time domain reflectometry techniques by implementing it in a computer program, and the simulation results are discussed.
Corrosion Study of Galvanized Ultra High Strength Steel Reinforced Overhead Transmission Conductors
International Journal of Engineering & Technology
Overhead high voltage transmission conductors used worldwide are produced in several configurations. A multi-strand conductor of the type ACSR330 is typically used for 275 kV overhead transmission lines. The conductor is composed of 7 inner strands of Ultra High Strength Galvanized Steel for the mechanical support of the conductor and 26 strands of high conductivity Aluminum wires meant for power transfer over long distances. During the use, weather conditions and power fluctuations tend to degrade the properties of these conductors. In the present work, study of the state of galvanization and oxidation of an ACSR330 conductor is undertaken with a view to understand the effectiveness of the loss in corrosion protection and changes in the zinc coating on the galvanized steel strands after use for 25 to 30 years. The Scanning Electron Microscopy (SEM), X Ray Diffraction (XRD) and Energy Dispersive Analysis through X rays (EDAX) provide a very useful insight into the state of the condu...
An Investigation of Temperature and Wind Impact on ACSR Transmission Line Sag and Tension
Engineering, Technology & Applied Science Research, 2018
Power transmission is mainly based on overhead transmission lines with conductors being supported by transmission towers. Transmission lines are subjected to environmental stress (temperature changes, winds, snow etc), have an impact on the surrounding areas (visual pollution, building restrictions) and experience heavy losses due to resistive, magnetic and capacitive effects. Thus, proper modeling and installation of these conductors are necessary. The conductors are generally installed in a catenary shape to minimize the capacitive effects and to balance the tension. This paper presents an investigation on the sag and tension behavior under different temperature and wind of ACSR (Aluminum Conductor-Steel Reinforced) lines. Four different cases of temperature and wind are tested to calculate sag and tension. Simulation setup is done in ETAP (electrical transient and analysis program). Results are recorded and discussed.