Materials Literature
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Relevant standards such as the IEC60270 concentrate on a measurement frequency band below 1 MHz and on lumped, i.e. non-distributed test objects. On-line partial discharge measurements often require using higher frequencies to avoid noise interference. With respect to the basic gas discharge physics, the rise time of…
Space charge formation at interfaces between polyethylene and other polymeric materials were observed using a PEA method. Many polymeric materials are proposed to be used as the pre-molded joint for XLPE insulated cables. However, there are few investigations of space charge accumulation at the interface between diffe…
This paper reports on a study of the influence of the level of alumina trihydrate (ATH) on the electrical insulation properties and the tracking and erosion resistance of high temperature vulcanized silicone rubber (HTV-SIR). The electrical resistance of silicone rubber was measured using a high resistance meter. It d…
Based on the test results carried out on several types porcelain and AC composite insulators as well as a DC insulator in the artificial climate chamber, this paper puts forward the flashover performance of tested insulators at the atmospheric pressure of the altitude of 4000-meter and above concomitant with the conta…
It is known that space charge is formed in cables insulated with crosslinked polyethylene. It is assumed that the crosslinking byproducts or the crosslinked polymer morphology is responsible for the space charge. In order to examine these possibilities, low-density polyethylene, crosslinked polyethylene, and degassed…
Dependence of space charge distribution on voltage m application time is observed by pulsed electro-acoustic method in silicone rubber sample. Aluminum and copper are used as lower and upper electrodes, and a dc electric stress of 5-70 kV/mm is applied. Test results show that the primary space charges in samples are h…
Room temperature vulcanized (RTV) silicone rubber (SIR) coatings are used increasingly on outdoor HV porcelain and glass insulators and bushings when subjected to heavy pollution. An important property of the RTV-SIR coating is its ability to restore the hydrophobicity of the surface after a layer of contamination has…
The object of this paper is to clarify some of the items that regard space charge injection and accumulation in AC in polyethylene-based materials. In particular, the dependence of space charge injection threshold on supply frequency (from DC to 1000 Hz), as well as of space charge accumulation on electrical stress, f…
This paper discusses behavior of partial discharge (PD) under repetitive bipolar impulse voltage. Using different waveforms of square voltages, PD inception and elimination voltages (PDIV/PDEV) have been investigated in detail on 50 /spl mu/m air gap between J-shaped enameled wire and plane electrode with polyimide fi…
Insulation degradation mechanism and identification of defect types for cross-linked polyethylene (XLPE) cable and joint have not been cleared yet. Measurement of partial discharge (PD) is one of the most important things of testing the high voltage cable. In this paper, we investigated PD characteristics measured for…
This paper deals with the effect of humidity on Partial Discharge (PD) characteristics in a void with insulation-insulation configuration. The PD patterns were measured using the CIGRE Method-II specimen with various levels of relative humidity. Using the same experimental setup, the statistical time lag was also meas…
A testing apparatus for voltage endurance of film materials subjected to partial discharges on its surface was developed according to IEC-343 and ASTM-2275. It consists of electrode unit, power supply unit and control unit, and has the function of testing simultaneously six group samples. The single chip computer is u…
Variable Frequency Phase Resolved Partial Discharge Analysis (VF-PRPDA) is a newly developed method for partial discharge measurements. In this method the frequency of the applied voltage is variable and not fixed at the power frequency as in the standard PRPDA implementation. In this paper, simulations illuminate the…
Nanocomposite of low density polyethylene (LDPE)/TiO/sub 2/ was prepared via solution blending method. The disperse performance of TiO/sub 2/ in LDPE was observed with Scanning Electron Microscope. It is shown that TiO/sub 2/ could be dispersed uniformly in LDPE through controlling temperature and content of the solut…
Solidification/stabilization (S/S) treatment is used to treat hazardous wastes for disposal and in the remediation/site restoration of contaminated land. S/S is also an increasingly popular technology for brownfields (industrial property) redevelopment, since treated wastes can often be left on-site and to improve the…
A new type of insulating polymer, syndiotactic polypropylene prepared by metallocene catalyst has been found to exhibit much superior electrical, thermal and mechanical properties compared with those of conventional isotactic polypropylene, atactic polypropylene and polyethylene. These excellent characteristics of syn…
Abstract A survey of 18 paramagnetic species [L n Ru(NO)] k , including seven new examples studied by in situ electrolysis, reveals a surprisingly narrow range of EPR parameters despite a wide variety of ligands such as pyridine, polypyridines, imines, amines, nitriles, phosphanes, carbonyl, cyclopentadienides, halide…
Abstract Summary: We studied changes in the mechanical properties of polyelectrolyte‐multilayer capsules induced by YF 3 ‐nanoparticle formation inside the layers. Using direct‐deformation measurements by colloidal probe atomic force microscopy (AFM), we found that the nanoparticle formation increases the capsule stif…
Treatment of the complex ( 1 ) with HBF 4 ·OEt 2 in diethyl ether−acetone (2:1) affords the elongated dihydrogen derivative ( 2 ), which reacts with NaCl and CsF to give (X = Cl ( 3 ), F ( 4 )). The X-ray diffraction studies on 2 and 4 and DFT calculations on the model complexes ( 1t ), ( 2t ), and (X = Cl ( 3t ), F (…
Abstract There has been a growing interest in tunable devices applications such as filters, phase shifters, and resonators. Both of ferromagnetic and ferroelectric materials have strong advantages in the high tunability and stability. Therefore many reports have been published by employing ferrite or dielectric materi…