Analysis of an application possibility of geopolymer materials as thermal backfill for underground power cable system

Ocłoń, Paweł; Cisek, Piotr; Matysiak, Marcelina

doi:10.1007/s10098-020-01942-8

Cited by 14 publications

(5 citation statements)

References 22 publications

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“…Thermal backfill materials have significantly higher thermal conductivity than the mother soil and can enhance the heat transfer from the buried power cables. In this case, the power cable temperature does not exceed a certain limit of the temperature [12,44,45]. In addition, an advantage of proper backfill material is the stability in time of its thermal conductivity [45].…”

Section: Soil Thermal Conductivitymentioning

confidence: 99%

“…Thermal assessment of an underground power cable is useful to obtain its ampacity, i.e., its current rating. This parameter represents the maximum electrical current flowing through an operated power cable conductor without exceeding the maximum limits of its operating temperature [12]. To calculate the power cable ampacity, it is necessary to evaluate some aspects that can affect the operational buried power cable characteristics.…”

Section: Introductionmentioning

confidence: 99%

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Concepts and Methods to Assess the Dynamic Thermal Rating of Underground Power Cables

et al. 2021

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With the increase in the electrical load and the progressive introduction of power generation from intermittent renewable energy sources, the power line operating conditions are approaching the thermal limits. The definition of thermal limits variable in time has been addressed under the concept of dynamic thermal rating (DTR), with which it is possible to provide a more detailed assessment of the line rating and exploit the electrical system more flexibly. Most of the literature on DTR has addressed overhead lines exposed to different weather conditions. The interest in the dynamic thermal rating of power cables is increasing, considering the evolution of computational methods and advanced systems for cable monitoring. This paper contains an overview of the concepts and methods referring to dynamic cable rating (DCR). Starting from the analytical formulations developed many years ago for determining the power cable rating in steady-state conditions, also reported in International Standards, this paper considers the improvements of these formulations proposed during the years. These improvements are leading to include more specific details in the models used for DCR analysis and the computational methods used to assess the power cable’s thermal conditions buried in soil. This paper is focused on highlighting the path from the initial theories and models to the latest literature contributions. Attention is paid to thermal modelling with different levels of detail, applications of 2D and 3D solvers and simplified models, and their validation based on experimental measurements. A salient point of the overview is considering the DCR impact on reliability aspects, risk estimation, real-time calculations, forecasting, and planning with different time horizons.

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Section: Soil Thermal Conductivitymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Concepts and Methods to Assess the Dynamic Thermal Rating of Underground Power Cables

et al. 2021

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“…Reference [10] calculated the conductor temperature for a typical water-cooled cable buried in a flat horizontal arrangement, and the simulation results showed that water-cooled pipes can effectively increase the ampacity. However, the thermal conductivity of water is not enough to meet the existing load demand, so existing studies have used different high-thermal-conductivity materials to reduce the thermal resistance of the external environment to improve the ampacity, and the improvement effect has been verified by experiments or finite element simulation [11][12][13][14][15][16][17][18][19]. In [20], an electromagnetic thermal coupling model of two parallel cables was established using the finite element method.…”

Section: Introductionmentioning

confidence: 99%

Research on the Improvement of Cable Ampacity in Dense Cable Trench

Zhang,

Yu,

Liu

et al. 2024

Energies

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Due to the influence of many factors, distribution cables are often densely placed at the bottom of the cable trench. As a result, it is easy for distribution cables to become the thermal bottleneck of the whole transmission line. To address this dilemma, this paper establishes a finite element simulation model of a cable trench to analyze the hot spots of cables with different arrangements in the cable trench. Then, the model’s accuracy is verified based on real temperature rise experiments. For an arrangement with overheating risk, the ampacity improvement method of filling the cable trench with high-thermal-conductivity material was proposed, and the ampacity improvement effect under different filling ratios was assessed. Finally, combined with the analysis of economic benefit and cost, the method of determining the optimal filling ratio was used, and the impact resistance of the cables under the impact of new energy load was analyzed. The results indicate that, for the case of the optimal filling ratio, the cables in the dense cable trench showed superior impact resistance. The investigations in this paper make significant contributions to the promotion of the maximum utilization of cables.

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“…Generally, the temperature of the core conductor reduced from 64 ο C to 48 ο C, while the thermal conductivity of the surrounding back ll materials increased from 0.5 Wm − 1 K − 1 to 1.0 Wm − 1 K − 1 [12,13]. On the other hand, the improper dissipation of heat causes the migration of moisture from the vicinity of the power cable and thus, dry zone formation occurred due to loss of moisture causes thermal instability [15][16][17]. Therefore, the thermal back ll materials should have adequate thermal properties and favorable water retention capacity, which will facilitate the heat transfer easily from the heat source to the surrounding area with minimal moisture migration [18,19].…”

Section: Introductionmentioning

confidence: 99%

Thermophysical Properties of Bentonite–Sand/Fly Ash-Based Backfill Materials for Underground Power Cable

2023

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The surrounding (back ll) materials around the underground power cable systems are essential for dissipiating the heat away from it, during the exertion phases. The heat dissipiation restrains the thermal instability and risk of progressive drying of the back ll materials, thus, reduce thermal stress on power cable. Thermal instability is the reduction of thermal properties (conductivity or diffusivity) due to migration of moisture because of heat accumulation. Thus, the back ll materials should have adequate thermal properties and favorable water retention capacity, which will falicitate the heat transfer easily from the heat source to the surrounding area with minimal moisture migration. The bentonite have high water retention capacity, but low thermal conductivity. Sand/ y ash exhibit low water retention and have higher thermal conductivity than bentonite. The addition of bentonite promote the water holding capacity and thermo-physical properties of sand and y ash. Therefore, this study presents the thermal properties of back ll materials, bentonite-y ash (B-F) and bentonite-sand (B-S) at varying weigth-percent of sand and y ash with bentonite. various compositions of the mixtures were compacted to varying dry densities and water contents and thermal properties variation of back ll materials were measured using a dual thermal needle probe 'KD2 Pro 2008' at room temperature. The study deals with systematic evaluation of the volumetric speci c heat capacity, thermal conductivity and diffusivity of back ll materials against varying dry density and water content. The threshold water content (TWC) has been determined from the thermal diffusivity-water content variation curve and it has correlated with plastic limit (PL) and optimum mosite conetn (OMC). Thereafter, the e cacy two thermal conductivity prediction models also were statistically evaluated with respect to experimental results.

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Analysis of an application possibility of geopolymer materials as thermal backfill for underground power cable system

Cited by 14 publications

References 22 publications

Concepts and Methods to Assess the Dynamic Thermal Rating of Underground Power Cables

Concepts and Methods to Assess the Dynamic Thermal Rating of Underground Power Cables

Research on the Improvement of Cable Ampacity in Dense Cable Trench

Thermophysical Properties of Bentonite–Sand/Fly Ash-Based Backfill Materials for Underground Power Cable

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