Harmonic-based thermal analysis of electric arc furnace's power cables considering even current harmonics, forced convection, operational scheduling, and environmental conditions

2021 ◽  
Vol 170 ◽  
pp. 107135
Author(s):  
Ahmadreza Jamali-Abnavi ◽  
Hamed Hashemi-Dezaki ◽  
Abdorrasoul Ahmadi ◽  
Ehsan Mahdavimanesh ◽  
Mohammad-Jafar Tavakoli
Keyword(s):  
Thermal Analysis ◽  
Forced Convection ◽  
Environmental Conditions ◽  
Electric Arc ◽  
Power Cables ◽  
Current Harmonics

The Thermooxidation and Resistance to Moulds Action of Some Polyethylene Sorts Used at Anticorrosive Insulation of the Underground Pipelines

2017 ◽  
Vol 54 (3) ◽  
pp. 447-452 ◽  
Author(s):  
Adriana Mariana Bors ◽  
Nicoleta Butoi ◽  
Alina Ruxandra Caramitu ◽  
Virgil Marinescu ◽  
Iosif Lingvay
Keyword(s):  
Heat Treatment ◽  
Thermal Analysis ◽  
Culture Media ◽  
Power Cables ◽  
Polymerization Degree ◽  
Crosslinking Degree ◽  
Underground Pipelines ◽  
Predominant Process ◽  
Underground Power Cables ◽  
Coupled Techniques

Polyethylene (PE) insulations have a wide applicability in the insulation of both underground pipelines and underground power cables. In this context, by coupled techniques of thermal analysis (TG/DTG+DTA) and microbiological determinations, have been studied thermooxidability and resistance to moulds action of some polyethylene sorts. Following the processing of the experimental data obtained by thermal analysis it was found that during the applied heat treatment (100 grd C), in the first approx. 380 h, there is a growth of LDPE (low density polyethylene) polymerization degree by elongation of the aliphatic chains, after which the predominant process consists in the structure crosslinking. For MDPE (mean density polyethylene) samples, during the thermal treatment applied, it was found that the crosslinking degree of polyethylene (PE) increased without significant molecular weight change (with all the related consequences of increasing the weight of the tertiary and quaternary carbon atoms in the molecule). Microbiological determinations have highlighted that the resistance to filamentous fungal action of LPDE is higher than that of the investigated MDPE. It was found that after heat treatment applied (1000 h and 100 oC), both at LDPE and at MDPE, decreases the resistance to moulds action is decreased. It has also been found that moulds action resistance is substantially decreased when inoculated culture media and PE samples are exposed to an alternative electric field of 50 Hz - 6 Vrms/cm.

Fem-Based Thermal Analysis of Underground Power Cables Located in Backfills Made of Different Materials

2015 ◽  
Vol 47 (5) ◽  
pp. 770-780 ◽  
Author(s):  
P. Ocùoñ ◽  
D. Taler ◽  
P. Cisek ◽  
M. Pilarczyk
Keyword(s):  
Thermal Analysis ◽  
Power Cables ◽  
Underground Power Cables

Thermal analysis of underground electrical power cables buried in non-homogeneous soils

2011 ◽  
Vol 31 (5) ◽  
pp. 772-778 ◽  
Author(s):  
Roberto de Lieto Vollaro ◽  
Lucia Fontana ◽  
Andrea Vallati
Keyword(s):  
Thermal Analysis ◽  
Electrical Power ◽  
Power Cables

Globe Temperature and Its Measurement: Requirements and Limitations

2019 ◽  
Vol 63 (7) ◽  
pp. 743-758
Author(s):  
A Virgílio M Oliveira ◽  
António M Raimundo ◽  
Adélio R Gaspar ◽  
Divo A Quintela
Keyword(s):  
Forced Convection ◽  
Environmental Conditions ◽  
Response Times ◽  
Air Velocity ◽  
Globe Temperature ◽  
Different Diameters ◽  
Relative Differences ◽  
Correction Equations

Abstract This study addresses the measurement of the globe temperature. For this purpose, two globe thermometers with different diameters (50 and 150 mm) and a variety of thermal environmental conditions were considered. The assessments of the response times and of the influences of the globe diameter and the air velocity on the measured globe temperatures are discussed. The results of the response times clearly put in evidence that the values usually stated in the literature can be questioned and that longer measurement periods must be considered. In fact, response times >30 min were obtained in 68% of the tests performed. Moreover, differences >20ºC were obtained between the 150 and 50 mm sensors, highlighting the influence of the globe diameter. The analysis of the effect of the air velocity on the globe temperature shows mean relative differences >30% between tests in still air and with the higher air velocity considered (1.81 m s–1). On the basis of measurements carried out with the 50 mm globe, correction equations to the standard globe temperature for both natural and forced convection are proposed.

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