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This study investigates the potential and limits of polymer concrete for outdoor insulation. Polymer concrete with a UV resistant cycloaliphatic epoxy matrix and a filler content of up to 87.5 wt% was formulated. Whereas an increase in filler content reduced strain to failure to about 0.46% (porcelain: 0.1%; 66 wt% filled epoxy: 1.26 %) the Young's modulus in compression drastically increases up to...
This paper presents a new on-line Partial Discharge Detection Method of cable with the capacitor sensors. The propagation rule of PD signal in the cable joint of the cross-bonding link-system was studied by the method of combining ATP simulation and actual measurement, laying the foundation for the practical application of such sensor.
This paper describes the degradation properties of bisphenol A type epoxy with a carboxyl-terminated butadiene-acrylonitrile (CTBN) and nano-clay. For evaluation of degradation by radiation, gamma rays of 500 kGy, 1000 kGy, and 1500 kGy were used to irradiate the samples at the dose rate of 8 kGy/hr. The degradation properties of the gamma-ray irradiated samples were measured using a thermogravimetric...
Currently, studies of microsecond and sub-microsecond electrical breakdown in liquid water and water solutions are experiencing their renaissance period due to the development of advanced pulsed power systems and emerging technologies for environmental applications and plasma medicine. The present paper is focused on an investigation of polarity effects in sub-microsecond discharges in water. Distilled...
We consider the development of a streamer in a homogeneous electric field with the closure of the positively charged head on the cathode. The physical conditions providing the closure are described.
In this study, alternating voltages with different values were employed to study the behavior of Ar mixed with SF6. The percentage of SF6 in Ar was varied from 5% to 90% at a total gas pressure of 50 kPa, 100 kPa, 150 kPa and 200 kPa, and the breakdown voltages of each gas mixture were recorded. Similar to earlier studies under static electric fields and impulse fields, it is observed that the breakdown...
Epoxy nanocomposites can be used as electrical insulation material in various high voltage applications, due to their improved ductility, fatigue resistance, in combination with enhanced electrical properties, compared to the neat epoxy. In the previous work, the mechanisms leading to these improvements in Al2O3 nanoparticles filled epoxy nanocomposites were investigated [1, 2]. It was shown that...
The short-medium term behaviour of pure and nanocomposite polypropylene is investigated: in particular both breakdown voltage tests and electrical aging tests are performed applying sinusoidal waveforms at industrial frequency (50 Hz) to the studied materials. The nanocomposite material is obtained by the dispersion of 10% by wt. of inorganic nanosized clay inside the organic polypropylene (PP) matrix...
This paper proposes a set of on-line monitoring system for capacitive traction power equipments applied in high-speed railway, such as high-voltage bushing, current transformer, potential transformer, and zinc oxide arrester. The electric circuit for the on-line system including zero-flux type current sensor and data acquisition unit is described in detail. The accuracy is enhanced by applying the...
Transmission and distribution transformers are a critical part of the electricity generation and distribution network. The potential consequence of transformer failure can cause operation disruption and financial losses. In recent years, magnetic nanoparticles have been used to enhance the dielectric breakdown strength of transformer oil. Considering the inherent magnetic property of the magnetite...
Due to the geometry configure of composite insulator, the electric field strength near the two ends of composite insulator is always strong. The high electric field strength can cause the partial discharge on the insulation material and the surface of the metal electrodes, and bring premature aging of the insulator. In this paper, a new optimization method on the electric field distribution of composite...
The DC contamination flashover performance of composite insulators with different sheds design has been investigated at high altitude using up and down method. The experimental results demonstrated that the 50% flashover voltage do not have a monotonic relation with the leakage distance, which is different from classical theory. The shed spacing and the shed dimensions both have significant influence...
The existing controllable spark gap has not been able to be widely applied to the high voltage grid so far mainly due to the constraint of reliability. This paper introduces a conceptual design of a new type of controllable multi-spark gap which improves the reliability dramatically on working principle. The multi-spark gap is composed of multiple air gaps and chained R-C network for producing frequency-dependent...
For specific properties of polymer nanocomposites, we focused on the dispersibility of nanoparticles and its influence on dielectric property. In order to control the dispersibility, we used ultrasonic wave (USW) and centrifugal force (CF). In this paper, we investigated the influence of nanoparticle content on permittivity characteristics of epoxy/alumina nanocomposites. As the result, we clarified...
Ice accumulation on insulator strings and power transmission lines cause serious accidents in many cold regions around the world. The progress of ice accumulation is profoundly affected by surface characteristics such as hydrophobicity and surface heating. In this paper, a certain semiconducting RTV silicone rubber that can generate heat was developed. The heat exchange progress was investigated and...
The thermo-mechanical and the electrical characterization of some nanocomposites prepared from bisphenolic epoxy resins and different nanoclays are presented. The study of the nanocomposites morphology revealed a good dispersion of the nanoclay in the epoxy polymer. The dynamic modulus was found to be higher for the nanocomposites irrespective of the nature of the adopted clay. The space charge accumulation...
The aim of this paper is to investigate the relationship between mechanical stress and a new conduction mechanism discovered recently, that is conduction through fast charge pulses in insulting polymers. Theories and experimental data suggested that such pulses constitute charge solitons moving in the insulation bulk thanks to the induced compressive force applied to the natural relaxation of the...
For the size reduction and the reliability enhancement of electric power equipment, the electric field stress around solid insulators should be optimized. For the relaxation and optimization of the electric field stress, the application of FGM (Functionally Graded Materials) with spatial distribution of dielectric permittivity can be an effective solution. In this paper, we investigated the fabrication...
A solution algorithm for the ion drift-diffusion model is presented, based on the finite volume method (FVM). We further propose a new discretization scheme for the charge migration term which accurately accounts for discontinuities of material properties and solution variables across material interfaces.
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