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I would like to take this opportunity to welcome you to the 33rd Electrical Insulation Conference (EIC), a fully sponsored conference of the IEEE DEIS. As the first General Chair of this conference series from outside of North America, I chose Seattle as the location for this year's meeting because of its great reputation as a friendly city with many attractions as well as strong links to industry...
For HVDC cables, dielectric field inversion normally occurs due to the temperature drop across the insulation. Unlike AC applications where the field distribution is primarily determined by the cable geometry, the DC field can be significantly affected by the load current and hence the dielectric temperature profile. Higher temperature drops lead to higher electrical stress at the insulation screen,...
The reliability of the cable depends on production conditions and the insulation material. In this study, an EPR insulator specimen was fabricated for use in experiments. In addition, we selected the Arrhenius model, which is widely used for lifetime prediction, and the Weibull model for statistical analysis. The suitability between the two models was evaluated. The temperature change of material...
This paper investigates the electric potential and field of a two phase (gas-liquid) system. The study uses finite element analysis (FEA) techniques to investigate the impact of a gas bubble on the bulk electric field. The FEA model is expanded to consider the multiple bubble breakdown probability using Monte Carlo techniques. The numerical results demonstrate that compared with bubble quantity, bubble...
Insulating pipe sections from epoxy and ceramic are presented for use in two-phase cooling systems, where the evaporator is on electric potential whereas the condenser is on ground. For the example of 2 kV system voltage and 12.6 kV impulse voltage, a dimensioning procedure is presented, taking into account air, solid insulation, and refrigerant. The latter must be considered in vapor, liquid and...
Inorganic sediments frequently deposit on the pin-type grading electrodes installed in the inner cooling circuits for high voltage converter valves. This investigation focuses on the distributing characteristics of deposited sediments. Field data have been collected from three ±500kV converter stations. Sediment distributions corresponding to different valve tower structures are summarized. The relationships...
For studies of insulation coordination at industrial frequency transmission line must be modelled with much more details than for other studies, like load flow and short circuit analyses. In other words, that usual representation of the transmission line by a single quadrupole Pi circuit is not applicable. In fact, all of the three-phase conductors must be analyzed separately though the determination...
For the wide area and variable weather in China, the composite insulators will endure several terrible conditions. Strong wind area is very special in China or the other worldwide places. Now the transmission lines problems caused by wind are mainly focusing on tower strength, conductor galloping and external insulation selection. The sheds cracks of the composite insulators at 750kV AC lines in Xinjiang...
Dynamic Line Rating is an effective way of uprating transmission lines in a cost efficient way, without reconductoring old lines, or building new ones. Uprating of equipment found in power systems has always been an issue. Having higher ampacity rates over a power line due to DLR, increased thermal stress occurs not only on the conductors, but on insulators, and on other pieces of equipment as well...
In this paper, space charge formation in epoxy resin has been measured at different applied electric fields using the pulsed electroacoustic technique to reveal the charge injection threshold field. The influence of electrode material on the charge injection has also been investigated. It has been found that the threshold field value for negative charge injection is much lower than that of positive...
The spatial resolution of the measurement methods used to estimate the microscopic distribution of charges in insulating materials is not sufficient to study the distribution at the interface of metals and semi-conductors. In this paper it is experimentally shown that applying the Pressure Wave Propagation (PWP) method to an aluminum sample generates a signal corresponding to the charges distribution...
Power transformers are among the most critical and valuable assets in an electric utility. Their failure can compromise system security, reliability and result in load shedding. These factors coupled with the long lead times involved in replacement mean that condition based monitoring is fast becoming the norm for minimization of down time. Among the gamut of available test methods, Frequency Response...
In HVDC (high voltage direct current) insulation systems, the conductivities of the insulating materials pressboard and oil are the relevant material parameters that determine the field distribution. The pressboard conductivity depends on various parameters, which can be categorized in service-parameters (e. g. time of energization, water content, impregnating fluid) and parameters during pressboard...
Under AC/DC combined electric field, the oil-pressboard insulation of the converter transformer accumulates space charges to generate a partially distorted non-uniform field and thus affects the electric strength distribution of the insulation system. The present research uses the needle-plate electrode to simulate the distorted non-uniform electric field fostered by the space charges and adopts the...
Condition assessment of power components such as power transformers and their bushings depends on the interpretation of data obtained from the monitoring systems. Various defects in their insulation would behave differently under electrical stresses. Surface discharge on the oil-paper interface is one of the defects which can be responsible for the failure of those components. Power system transients...
A novel sensor used in detection of hydrogen concentration dissolved in transformer oil was proposed based on fiber Bragg grating (FBG). Palladium was introduced as hydrogen sensitive material and silver was alloyed to improve permeability in hydrogen sensitive layer. Meanwhile membrane of titanium was fabricated for enhancing the adhesion between fiber and hydrogen sensitive layer. The thin film...
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