Some Factors Affecting the Breakdown Strength of Solid Dielectrics: A Short Review

Danikas, M. G.; Vardakis, G. E.; Sarathi, R.

doi:10.48084/etasr.3479

Cited by 4 publications

(2 citation statements)

References 62 publications

(94 reference statements)

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“…The existence of space charges and partial discharges inside the dielectrics plays a dominant role in the deterioration of their insulating capability. In [31][32][33], their contribution was analyzed, showing that these phenomena are present continuously in the HV industry and the related apparatus and the efforts to control and to study them may improve the HV apparatus reliability and insulation life time function. Charge packets propagation, space charges, partial discharges, electrical trees emanation and propagation, and electrical dipole formation are phenomena strongly correlated to each other, defining thus and affecting the insulating capability of materials.…”

Section: Table V Summarizes the Experimental Results From 7 Papersmentioning

confidence: 99%

A Short Review on Charge Packets and Space Charge Properties Inside Dielectrics

Vardakis,

Danikas,

Achillides

2023

Eng. Technol. Appl. Sci. Res.

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An effort to highlight the role of space charges inside dielectrics and their propagation is made in the present paper. Solid insulating materials in various parts of high voltage devices and machines are crucial for the insulating performance and their reliable functioning duration. Space charge distributions and space charge propagation in the form of pulses, called charge packets, are studied in this paper pointing out on one hand the initiating mechanisms and on the other hand the propagation mechanisms of charges inside dielectrics, as they are introduced in the scientific literature. Experimental data are used from other papers, mainly those referring to space charge distributions versus space and simultaneously versus time in a classification attempt of the aforementioned parameters.

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Section: Table V Summarizes the Experimental Results From 7 Papersmentioning

confidence: 99%

A Short Review on Charge Packets and Space Charge Properties Inside Dielectrics

Vardakis,

Danikas,

Achillides

2023

Eng. Technol. Appl. Sci. Res.

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“…The reliability of coils is quite different depending on the type of coil, the field of use, the conditions of construction, and the manner of maintenance and operation, but, as a guide, for coils built in a single layer (which usually have low inductance), the failure rate can be considered λ = (0.01-0.017)%/10 3 h [46,47]. For coils made in several layers, the probability of failure increases considerably (3-4 times) because it is possible to have short circuits between turns, but especially between layers.…”

Section: Reliability Of Real Ac Coilsmentioning

confidence: 99%

Aspects Regarding of Passive Filters Sustainability for Non-Linear Single-Phase Consumers

Diniș,

Popa,

Cunțan

et al. 2024

Sustainability

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The efficient use of electrical energy (an important component of sustainability) has become increasingly important for electrical consumers (industrial and non-industrial) as we face the challenges of climate change and the need to protect the environment. This theme is essential for guaranteeing a secure and sustainable future for both present and future generations. The power quality and the efficiency of electrical energy are connected to each other. Some power quality problems are caused by natural and unpredictable events, but many disturbances affecting power quality are caused by suppliers and consumers. One of the most important parameters in power engineering is the power factor, which indicates the degree of efficient use of electrical energy. Harmonics is the most important dynamic component of power quality, which affects the operation of electrical equipment and, at the same time, reduces the power factor. Harmonic sources in power systems are generally associated with nonlinear loads. To analyze the operating of passive filters (series L, shunt LC, T type LCL), two groups of experiments (relevant consumers were chosen for the industry as well as from the household sector) were carried out with single-phase nonlinear consumers: in the first group of experiments, a variable-frequency drive is used to supply a three-phase induction motor with variable load; in the second group of experiments, compact fluorescent lamps and LED lamps were used. Following the experiments, it was found that the difficulty of calibrating coils (to size a filter), especially the coils with a core, and the change in electrical properties over time for capacitors. For a certain type of consumer, the improvement of the current waveform depends on the type of filter used, the possibility of improving the power factor (to use electrical energy efficiently), and the role of the source impedance, which is particularly important to improve the efficiency of passive filters. Through the appropriate choice of the passive filter, a decrease in the deforming regime is obtained, with a slight decrease in the active power, and by increasing the power factor, a decrease in the losses of electrical energy from the electrical networks is obtained, with direct implications for the emission of greenhouse gases.

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Experimental Study on the Factors of the Oil Shale Thermal Breakdown in High-Voltage Power Frequency Electric Heating Technology

Sun

Liu

et al. 2022

Energies

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We conducted an experimental study on the breakdown process of oil shale by high-voltage power frequency electric heating in-situ pyrolyzing (HVF) technology to examine the impact mechanisms of the electric field intensity, initial temperature, and moisture content on a breakdown, using Huadian oil shale samples. A thermal breakdown occurred when the electric field intensity was between 100 and 180 V/cm. The greater the electric field intensity, the easier the thermal breakdown and the lower the energy consumption. The critical temperature of the oil shale thermal breakdown ranged from 93 to 102 °C. A higher initial temperature increases the difficulty of breakdown, which is inconsistent with the classical theory of a solid thermal breakdown. The main factor that affects the electrical conductivity of oil shale is the presence of water, which is also a necessary condition for the thermal breakdown of oil shale. There should be an optimal moisture content that minimizes both the breakdown time and energy consumption for oil shale’s thermal breakdown. The thermal breakdown of oil shale results from heat generation and dissipation. The electric field intensity only affects the heat generation process, whereas the initial temperature and moisture content impact both the heat generation and dissipation processes, and the impacts of moisture content are greater than those of the initial temperature.

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Some Factors Affecting the Breakdown Strength of Solid Dielectrics: A Short Review

Cited by 4 publications

References 62 publications

A Short Review on Charge Packets and Space Charge Properties Inside Dielectrics

A Short Review on Charge Packets and Space Charge Properties Inside Dielectrics

Aspects Regarding of Passive Filters Sustainability for Non-Linear Single-Phase Consumers

Experimental Study on the Factors of the Oil Shale Thermal Breakdown in High-Voltage Power Frequency Electric Heating Technology

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