scholarly journals THE INFLUENCE OF EXTRANEOUS SOURCES OF THERMAL ENERGY ON THERMAL STABILITY AND BREAKDOWN VOLTAGE OF ELECTRICAL INSULATION DURING ITS THERMAL BREAKDOWN

2021 ◽  
Vol 2021 (2) ◽  
pp. 20-25
Author(s):  
R. Vozhakov ◽  
◽  
V. Kyrylenko ◽  
◽  
◽  
...  
Keyword(s):  
Thermal Stability ◽  
Breakdown Voltage ◽  
Thermal Energy ◽  
Breakdown Strength ◽  
Thermal Power ◽  
Thermal Balance ◽  
Electrical Insulation ◽  
Operating Voltage ◽  
Thermal Breakdown ◽  
Dielectric Parameters

The article is devoted to the analysis of thermal breakdown of insulation of electrical and power equipment due to disturbance of its thermal balance. The analysis was performed within the simplest model of thermal breakdown while ignoring the temperature distribution in the insulation volume. Particular attention is paid to the influence of extraneous sources of thermal energy on the thermal stability and the breakdown voltage of the electrical insulation structure. From the heat balance equation and the condition of thermal balance disturbance between the total thermal power in the insulation and the heat transferred into the surroundings, have been found analytical expressions that take into account the influence of extraneous sources of thermal energy on the critical operating temperature and the breakdown voltage of the insulation. The influence of extraneous sources of thermal energy on the dependence of the breakdown voltage on the dielectric parameters and the cooling conditions was analyzed. It is shown that the breakdown voltage of the insulation decreases exponentially with the increase of the power of extraneous heat sources and the temperature coefficient of tgδ, as well as the deterioration of the heat transfer conditions. It is established that the critical dielectric losses in the insulation leading to the breakdown do not depend on the power of extraneous sources of thermal energy. It is proposed to increase the electrical insulation safety factor for breakdown strength relatived to its operating voltage, taking into account the extraneous sources of heat, to ensure the stability of insulation against thermal breakdown in the presence of extraneous sources of thermal energy. References 10, figures 3.

Breakdown Strength Characteristic of RBDPO and Mineral Oil Mixture as an Alternative Insulating Liquid for Transformer

2013 ◽  
Vol 64 (4) ◽  
Author(s):  
Yusnida M. ◽  
Kiasatina Azmi ◽  
Mohd Azmier Ahmad ◽  
Zulkifli Ahmad ◽  
Mohamad Kamarol
Keyword(s):  
Breakdown Voltage ◽  
Strength Characteristic ◽  
Palm Oil ◽  
Kinematic Viscosity ◽  
Breakdown Strength ◽  
Environmental Concern ◽  
Mineral Oil ◽  
Electrical Insulation ◽  
Insulating Oil ◽  
Insulating Liquid

Mineral oil (MO) works as an important electrical insulation and coolant in transformer which is non-biodegradable and nearly running out. Therefore, for sustainable and environmental concern, an alternative biodegradable insulating oil that potential to replace the mineral oil is introduced. In view of that, the breakdown strength characteristic of Refined Bleached Deodorized Palm Oil (RBDPO) and MO mixtures were investigated by varying the mixing percentage of RBDPO from 0% to 100% at 40oC. The results showed that the breakdown strength of the oil mixture abruptly decline to the minimum breakdown voltage of 50 kV at  20% of  RBDPO mixture and gradually increased when  the ratio of the RBDPO is added. The highest breakdown strength is achieved 87kv at 80% of RBDPO content. The result of kinematic viscosity is also presented.

scholarly journals Improvement of DC Breakdown Strength of the Epoxy/POSS Nanocomposite by Tailoring Interfacial Electron Trap Characteristics

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1298
Author(s):  
Farooq Aslam ◽  
Zhen Li ◽  
Guanghao Qu ◽  
Yang Feng ◽  
Shijun Li ◽  
...  
Keyword(s):  
Epoxy Resin ◽  
Breakdown Voltage ◽  
Breakdown Strength ◽  
Deep Level ◽  
Simulation Method ◽  
Neat Epoxy ◽  
Interfacial Region ◽  
Chemical Calculation ◽  
Oligomeric Silsesquioxane ◽  
Underlying Risk

To date, breakdown voltage is an underlying risk to the epoxy-based electrical high voltage (HV) equipment. To improve the breakdown strength of epoxy resin and to explore the formation of charge traps, in this study, two types of polyhedral oligomeric silsesquioxane (POSS) fillers are doped into epoxy resin. The breakdown voltage test is performed to investigate the breakdown strength of neat epoxy and epoxy/POSS composites. Electron traps that play an important role in breakdown strength are characterized by thermally stimulated depolarized current (TSDC) measurement. A quantum chemical calculation tool identifies the source of traps. It is found that adding octa-glycidyl POSS (OG-POSS) to epoxy enhances the breakdown strength than that of neat epoxy and epoxycyclohexyl POSS (ECH-POSS) incorporated epoxy. Moreover, side groups of OG-POSS possess higher electron affinity (EA) and large electronegativity that introduces deep-level traps into epoxy resin and restrain the electron transport. In this work, the origin of traps has been investigated by the simulation method. It is revealed that the functional properties of POSS side group can tailor an extensive network of deep traps in the interfacial region with epoxy and enhance the breakdown strength of the epoxy/POSS nanocomposite.

scholarly journals Thermal stability of a waste-based alkali-activated material for thermal energy storage

2021 ◽  
Vol 3-4 ◽  
pp. 100014
Author(s):  
Patrick Keane ◽  
Rhys Jacob ◽  
Neil Trout ◽  
Stephen Clarke ◽  
Frank Bruno
Keyword(s):  
Thermal Stability ◽  
Energy Storage ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Alkali Activated ◽  
Thermal Stability Of

IMPROVING THE EFFICIENCY OF HOT GAS GENERATORS FOR HEATING AUTOMOTIVE EQUIPMENT

2021 ◽  
Vol 2 (143) ◽  
pp. 46-53
Author(s):  
Andrey V. Negovora ◽  
◽  
Makhmut M. Razyapov ◽  
Arseniy A. Kozeyev
Keyword(s):  
Heat Pipe ◽  
Thermal Energy ◽  
Thermal Power ◽  
Research Purpose ◽  
Gas Generator ◽  
Thermoelectric Converter ◽  
Remote Monitoring System ◽  
Hot Gas ◽  
Safety Research ◽  
Gas Generators

Hot gas generators are used as a source of thermal energy for pre-start preparation of motor vehicles in cold climatic conditions. Their wide application is due to the high thermal power and safety. (Research purpose) The research purpose is in determining the possibilities of using thermoelectric modules to reduce the energy consumption of the battery by hot gas generators. (Materials and methods) Authors used research methods based on the application of standard techniques, while the object of research was the power supply system of a thermal energy source. (Results and discussion) Authors conducted research on ways and methods to reduce the electric consumption of a hot gas generator by recuperating thermal energy into electrical energy using thermoelectric generator modules. The thermoelectric converters installed on the heat pipe of the hot gas generator, due to the high temperature difference, will allow to obtain a high value of the electromotive force. Modeling of the nozzle in the software package of the Ansys three-dimensional modeling system showed that part of the heat energy goes through the surface of the heat pipe. The article proposes the use of a nozzle with a thermoelectric converter installed on the outer surface of the cylinder instead of a heat pipe. The article presents the mathematical model of an improved hot gas generator nozzle. (Conclusions) The use of a thermoelectric converter for the utilization of thermal energy and the replacement of energy losses of the battery, which feeds the hot gas generator, will reduce the internal power losses of the battery and increase the technical readiness of automotive equipment. The introduction of a comprehensive heat treatment system, which is intelligently and functionally linked to a remote monitoring system, will significantly increase the service life of the units most exposed to temperature influences.

A technique for simultaneously improving the product of cutoff frequency–breakdown voltage and thermal stability of SOI SiGe HBT

2016 ◽  
Vol 25 (12) ◽  
pp. 124401 ◽  
Author(s):  
Qiang Fu ◽  
Wan-Rong Zhang ◽  
Dong-Yue Jin ◽  
Yan-Xiao Zhao ◽  
Xiao Wang
Keyword(s):  
Thermal Stability ◽  
Breakdown Voltage ◽  
Cutoff Frequency ◽  
Sige Hbt ◽  
Thermal Stability Of

Thermal breakdown in high voltage direct current cable insulations due to space charges

2018 ◽  
Vol 37 (5) ◽  
pp. 1689-1697 ◽  
Author(s):  
Christoph Jörgens ◽  
Markus Clemens
Keyword(s):  
Electric Field ◽  
Breakdown Voltage ◽  
High Voltage ◽  
Direct Current ◽  
Aging Effect ◽  
Radial Symmetry ◽  
Thermal Breakdown ◽  
Content Type ◽  
High Voltage Direct Current ◽  
Space Charges

Purpose In high voltage direct current (HVDC), power cables heat is generated inside the conductor and the insulation during operation. A higher amount of the generated heat in comparison to the dissipated one, results in a possible thermal breakdown. The accumulation of space charges inside the insulation results in an electric field that contributes to the geometric electric field, which comes from the applied voltage. The total electric field decreases in the vicinity of the conductor, while it increases near the sheath, causing a possible change of the breakdown voltage. Design/methodology/approach Here, the thermal breakdown is studied, also incorporating the presence of space charges. For a developed electro-thermal HVDC cable model, at different temperatures, the breakdown voltage is computed through numerical simulations. Findings The simulation results show a dependence of the breakdown voltage on the temperature at the location of the sheath. The results also show only limited influence of the space charges on the breakdown voltage. Research limitations/implications The study is restricted to one-dimensional problems, using radial symmetry of the cable, and does not include any aging or long-term effect of space charges. Such aging effect can locally increase the electric field, resulting in a reduced breakdown voltage. Originality/value A comparison of the breakdown voltage with and without space charges is novel. The chosen approach allows for the first time to assess the influence of space charges and field inversion on the thermal breakdown.

scholarly journals Heat Generated Using Luminescent Solar Concentrators for Building Energy Applications

Energies ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 5574 ◽  
Author(s):  
Quinn Daigle ◽  
Paul G. O’Brien
Keyword(s):  
Thermal Energy ◽  
Electricity Generation ◽  
Thermal Power ◽  
Building Energy ◽  
Diffuse Light ◽  
Solar Thermal Energy ◽  
Solar Concentrators ◽  
Energy Applications ◽  
Luminescent Solar Concentrators ◽  
Renewable Energy Generation

Luminescent solar concentrators (LSCs) are a promising technology for integration and renewable energy generation in buildings because they are inexpensive, lightweight, aesthetically versatile, can concentrate both direct and diffuse light and offer wavelength-selective transparency. LSCs have been extensively investigated for applications involving photovoltaic electricity generation. However, little work has been done to investigate the use of thermal energy generated at the edges of LSCs, despite the potential for harnessing a broad range of solar thermal energy. In this work, Newton’s law of cooling is used to measure the thermal power generated at the edge of LSC modules subjected to solar-simulated radiation. Results show that the dye in single-panel LSC modules can generate 17.9 W/m2 under solar-simulated radiation with an intensity of 23.95 mW/cm2 over the spectral region from 360 to 1000 nm. Assuming a mean daily insolation of 5 kWh/m2, the dye in the single-panel LSC modules can generate ~100 kWh/m2 annually. If the surface area of a building is comparable to its floor space, thermal energy generated from LSCs on the buildings surface could be used to substantially reduce the buildings energy consumption.

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