scholarly journals Remote Monitoring of Joints Status on In-Service High-Voltage Overhead Lines

Energies ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 1004 ◽  
Author(s):  
Carlo Olivieri ◽  
Francesco de Paulis ◽  
Antonio Orlandi ◽  
Giorgio Giannuzzi ◽  
Roberto Salvati ◽  
...  
Keyword(s):  
High Voltage ◽  
Transmission Lines ◽  
Remote Monitoring ◽  
Power Transmission ◽  
Measurement Data ◽  
Time Domain Reflectometry ◽  
Overhead Line ◽  
Voltage Transformer ◽  
Remote Monitoring System ◽  
On Line

This work presents the feasibility study of an on-line monitoring technique aimed to discover unwanted variations of longitudinal impedance along the line (also named “impedance discontinuities”) and, possibly, incipient faults typically occurring on high voltage power transmission lines, like those generated by oxidated midspan joints or bolted joints usually present on such lines. In this paper, the focus is placed on the application and proper customization of a technique based on the time-domain reflectometry (TDR) technique when applied to an in-service high-voltage overhead line. An extensive set of numerical simulations are provided in order to highlight the critical points of this particular application scenario, especially those that concern the modeling of both the TDR signal injection strategy and the required high-voltage coupling devices, and to plan a measurement activity. The modeling and simulation approach followed for the study of either the overhead line or the on-line TDR system is fully detailed, discussing three main strategies. Furthermore, some measurement data that were used to characterize the specific coupling device selected for this application at high frequency—that is, a capacitive voltage transformer (CVT)—are presented and discussed too. This work sets the basic concepts underlying the implementation of an on-line remote monitoring system based on reflectometric principles for in-service lines, showing how much impact is introduced by the high-voltage coupling strategy on the amplitude of the detected reflected voltage waves (also named “voltage echoes”).

Soot Concentration Remote Monitoring System Based on GPRS and CAN Bus

2012 ◽  
Vol 433-440 ◽  
pp. 6287-6292 ◽  
Author(s):  
Yan Jun Zhao ◽  
Cheng Yuan Bai ◽  
Bin Qu
Keyword(s):  
Monitoring System ◽  
Remote Monitoring ◽  
Can Bus ◽  
Measurement Data ◽  
Pollution Source ◽  
Scattering Method ◽  
Soot Concentration ◽  
Remote Monitoring System ◽  
Communication Technique ◽  
On Line

Along with the development of the computer and communication technique, the remote monitoring system is widely applied. The pollution source is distributed widely, so the pollution status is difficult to monitoring. The soot concentration remote monitoring system based on GPRS and CAN bus is introduced in the paper. The system adopts the transmission-scattering method to measure the soot concentration. The measurement data is collected by the MCU and sent to the management system through the CAN bus. The data is sent to the EPA through GPRS. The experiment result indicates that the remote monitoring system can on-line measures the soot concentration and improves the communication efficiency and accuracy.

scholarly journals Experimental Evaluation of 3D Tortuosity of Long Laboratory Spark Trajectory for Sphere-Sphere and Sphere-Plane Discharges under Lightning and Switching Impulse Voltages

Energies ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 7409
Author(s):  
Michał Molas ◽  
Marcin Szewczyk
Keyword(s):  
High Voltage ◽  
Transmission Lines ◽  
Development Process ◽  
Power Transmission ◽  
Measurement Data ◽  
Simulation Models ◽  
Leader Development ◽  
Deterministic Models ◽  
Lightning Leader ◽  
Line Design

Evaluation of attractive areas of high- and ultra-high voltage power transmission lines to direct lightning strokes is based on modeling of propagating progress of the lightning leader approaching the transmission line. The aim of the modeling is to determine the effectiveness of lightning protection for a given line design. The statistical models are currently being developed to extend the conventional deterministic models by embracing the randomness of the discharge channel in space and hence to reproduce the statistical distribution of the striking points. These models require experimental data for understanding of the lightning leader development process and to validate the model across the measurement data. This paper reports on the measured trajectories of discharge channels of long laboratory sparks in various high voltage laboratory arrangements. The sparks were initiated by switching and lightning impulses with peak values ranging from 1200 kV to 3364 kV of positive and negative polarity for two types of high-voltage electrode systems (sphere-sphere and sphere-plane), arranged at distances of 3.3 m and 5.5 m from each other. Statistical distributions of angles describing trajectory of discharge channels in space are reported for a total number of 540 recorded discharges. The results can serve as reference measurement data to develop and evaluate the accuracy of simulation models incorporating statistical nature of the lightning leader development process.

scholarly journals Global experience of HVDC composite insulators in outdoor and indoor environment

2020 ◽  
Vol 59 (1) ◽  
pp. 606-618
Author(s):  
Mohammad Akbar ◽  
Basharat Mehmood
Keyword(s):  
High Voltage ◽  
Direct Current ◽  
Transmission Lines ◽  
Power Transmission ◽  
Green Energy ◽  
Attractive Alternative ◽  
Hvdc Transmission ◽  
Ceramic Insulators ◽  
High Power Transmission ◽  
Aging Performance

AbstractHigh-voltage direct current (HVDC) transmission is known as green-energy transfer technology and has recently become an attractive alternative of high-voltage alternating current (HVAC) due to its high-power transmission capability and lower power loss. Use of composite insulators on direct current (DC) transmission lines experienced rapid growth in recent years due to their high hydrophobicity and better performance in contaminated environment than conventional ceramic insulators. During their service operation on DC lines, insulators are prone to more accumulation of contaminants due to unidirectional electric field. The contaminants under wet conditions allow leakage current to flow on the insulator surface. Being organic in nature, polymeric insulators have a tendency to age under the combined effects of electrical and environmental stresses. To fully understand the long-term aging performance of DC composite insulators, a detailed survey was considered necessary. Towards that end, this paper critically summarizes worldwide experience of aging performance of composite insulators in the field as well as in laboratory conditions.

scholarly journals Wind: generating power and cooling the power lines

2020 ◽  
Vol 17 ◽  
pp. 105-108
Author(s):  
Marko Kaasik ◽  
Sander Mirme
Keyword(s):  
Wind Speed ◽  
Electric Power ◽  
High Voltage ◽  
Transmission Lines ◽  
Power Transmission ◽  
Mixed Forest ◽  
Wind Farms ◽  
Power Line ◽  
Power Lines ◽  
Local Wind

Abstract. The electric power that can be transmitted via high-voltage transmission lines is limited by the Joule heating of the conductors. In the case of coastal wind farms, the wind that produces power simultaneously contributes to the cooling of high-voltage overhead conductors. Ideally this would allow for increased power transmission or decreased dimensions and cost of the conductor wires. In this study we investigate how well the wind speed in coastal wind farms is correlated with wind along a 75 km long 330 kW power line towards inland. It is found that correlations between wind speed in coastal wind farms at turbine height and conductor-level (10 m) are remarkably lower (R=0.39–0.64) than between wind farms at distances up to 100 km from each other (R=0.76–0.97). Dense mixed forest surrounding the power line reduces both local wind speed and the correlations with coastal higher-level wind, thus making the cooling effect less reliable.

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