Generated heat within power cable sheaths per unit time and volume

Kovač, Nikša; Grulovič-Pavljanič, Neda; Kukavica, Ante

doi:10.1016/j.applthermaleng.2012.11.020

Cited by 19 publications

(8 citation statements)

References 13 publications

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“…One of the earliest works is published by Comellini [11], who considers also the effect of soil impedance. Kovač [12] employs a similar formulation and he additionally demonstrates that modeling of the ground return path is not necessary when dealing with loss calculations. Hence, a formulation similar to that of Moutassem [13] is derived, which is also referred to [2].…”

Section: Filament Methods (Fm)mentioning

confidence: 99%

“…RFs for single-point bonding losses are found, by minimizing the square difference of λ1" obtained with FEA and the corrected IEC method. The new value of λ1" is shown in (12 (12) where RFSPB = λ1,New"/ λ1,IEC" is the Reductive Factor (RF) for single-point bonding case. Since λ1,New" should be in close agreement with λ1,FEA" (ideally λ1,New" = λ1,FEA"), the ratio λ1,FEA"/ λ1,IEC" is illustrated in Fig.…”

Section: ) Approximating Formulae Suggestedmentioning

confidence: 99%

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Impact of Proximity Effects on Sheath Losses in Trefoil Cable Arrangements

Chatzipetros

Pilgrim

2020

IEEE Trans. Power Delivery

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Induced losses are a significant part of the total losses generated in HVAC cables. Presently, IEC 60287-1-1 is used to calculate the ratio of induced loss in a cable's metal sheath to its conductor loss (λ1), assuming uniform current density in both conductors and sheaths. Although this assumption is reasonable for smaller cables, it is questionable for larger cables in close proximity, such as three-core (3C) export cables in Offshore Wind Farm (OWF) projects. The effects of this non-uniform current density cannot be easily treated via a straightforward, purely analytical approach, since conductor currents are not effectively represented by linear ones in larger cables, while sheath currents are also unevenly distributed. The present study employs 2-D Finite Element (FE) models to evaluate how accurate the Standard method for calculating the λ1 factor is in cables with non-magnetic armor. Their validity is further enhanced by means of Filament Method. IEC 60287 appears to overestimate the temperature, particularly for larger conductor sizes, by up to 7°C (8%). Finally, suitable Reductive Factors are suggested which could improve the accuracy of the IEC method.

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Section: Filament Methods (Fm)mentioning

confidence: 99%

Section: ) Approximating Formulae Suggestedmentioning

confidence: 99%

Impact of Proximity Effects on Sheath Losses in Trefoil Cable Arrangements

Chatzipetros

Pilgrim

2020

IEEE Trans. Power Delivery

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“…The cable temperature, for a given rate of heat production, is determined by the thermal conductivity of the soil, the temperature of the environment, and the geometry of the path between the cable and the environment. Many analytical (Neher and McGrath, 1957; Papagiannopoulos et al, 2013; Chatziathanasiou et al, 2013; de Lieto Vollaro et al, 2011b) and numerical (Ocłoń et al, 2015a, 2015b, 2016; Kovac et al, 2013; Canova et al, 2012; de Lieto Vollaro et al, 2011a; De Leon and Anders, 2008) studies have investigated the heat dissipation of buried electric cables. In these studies, however, it was not considered that heat dissipation strongly depends on the hydraulic dynamics and water content distribution in the soil (Taylor and Cavazza, 1954; de Vries, 1963; Cass et al, 1984).…”

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confidence: 99%

Estimation of Thermal Instabilities in Soils around Underground Electrical Power Cables

Kroener

Campbell²,

Bittelli

2017

Vadose Zone Journal

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Core Ideas We studied coupled water, vapor, and heat flow around underground cables. There is a water–vapor flow cycle in the soil around these cables. This water–vapor cycle breaks down at the critical heat dissipation rate. The critical heat dissipation rate depends on soil hydraulic properties. The decentralized production of electrical energy from wind requires the installation of more and more underground power cables. From an economic standpoint it is very important to estimate the cables' lifetime, which strongly depends on the temperature. A correct estimation of cable temperature requires an accurate description of the heat balance equation around the cable. Most of the models used to assess heat dissipation from cables, however, do not consider that the soil thermal conductivity strongly depends on soil water content and hydraulic dynamics in the vicinity of the cable. The high temperature around the cable induces a water–vapor cycle in the soil: liquid water evaporates near the cable, and this vapor condensates in the more distant and colder parts of the soil. Above a critical heat dissipation rate, the soil around the cable dries out and the water–vapor cycle breaks down. In this study, we analytically estimated the critical heat dissipation rate as a function of soil type, soil temperature, and water content. We validated the analytical estimation by comparison to a numerical solution of the coupled heat–water–vapor transport for various soil types and conditions. The numerical code was validated by simulating a soil drying experiment. The proposed estimation of thermal instabilities in soils could become a powerful tool in the design of underground electrical power cable systems.

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“…Alternating current effective conductor resistance is calculated in multiconductor low‐voltage cables based on FEM in balanced harmonic currents . Volumetric heat produced in solid bonding sheaths of high‐voltage cables is calculated with consideration of proximity effects in Kovac et al The calculations are based on balanced sinusoidal conductor currents that result in 0 current in sheaths. Calculation of eddy current loss in the magnetic pipe of high‐pressure fluid‐filled cables under balanced and unbalanced sinusoidal currents is performed by using FEM in Kuang and Boggs .…”

Section: Introductionmentioning

confidence: 99%

Electromagnetic and thermal analysis of underground power solid‐conductor cables under harmonic and unbalancing currents based on FEM

Rasoulpoor

Mirzaie

Mirimani

2017

Int J Numerical Modelling

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In this paper, electromagnetic and thermal analyses are performed on underground power solid-conductor cables under harmonic and unbalancing currents. The loss, life time, and produced magnetic field are calculated. Different balanced and unbalance load currents and also sinusoidal and harmonic profiles are considered. Moreover, the effects of different distances between cables are analyzed. Power cable losses and produced magnetic fields around power cables are computed based on electromagnetic analysis by using finite element method. Furthermore, finite element method thermal simulations are conducted to determine the cable life time based on Arrhenius model. Underground medium-voltage cables with metallic sheaths in flat and trefoil formations are considered. Metallic sheaths are bonded together and grounded in the single point or both ends. So, the effects of eddy and circulating currents of sheaths on power cable parameters are studied. Simulation results show the important effects of unbalancing and harmonic currents on the power cables parameters. Also, the effects are dependent on the harmonic frequency orders, installation method, and grounding system types.KEYWORDS electrical analysis, finite element method, magnetic field, power cable, thermal analysis

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Generated heat within power cable sheaths per unit time and volume

Cited by 19 publications

References 13 publications

Impact of Proximity Effects on Sheath Losses in Trefoil Cable Arrangements

Impact of Proximity Effects on Sheath Losses in Trefoil Cable Arrangements

Estimation of Thermal Instabilities in Soils around Underground Electrical Power Cables

Electromagnetic and thermal analysis of underground power solid‐conductor cables under harmonic and unbalancing currents based on FEM

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