The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
In this paper a parametric study of the dry-band arcing characteristics in the inclined plane tracking and erosion test is conducted under AC and DC voltages. The standard inclined plane testing apparatus is modified to promote stable and intense dry-band arcing, thereby analyzing the characteristics of the eroding dry-band arcing. The behavior of the liquid contaminant, which may bias the dry-band...
The paper describes a study into understanding the mechanism by which alumina tri-hydrate suppresses dry-band arcing erosion of silicone rubber under DC. Commercial silicone elastomers filled with alumina tri-hydrate to 25 and 58 wt% are exposed to the inclined plane tracking/erosion tests while simultaneously monitoring surface temperature. During the early stages of testing, a surface residue is...
In this paper the leakage current signature in the DC inclined plane test is examined for statistical indicators of the incipient erosion of silicone rubber. The mean, skewness and kurtosis are examined as useful indicators of the dry-band arcing current causing erosion. The moving window method is employed during the test to obtain an enhanced resolution in time. Simultaneous thermogravimetric-differential...
In this paper erosion of silicone rubber loaded with 30 wt% ATH and silica is investigated in the DC inclined plane tracking/erosion test as per ASTM D 2303. Reduced equivalent DC voltages have been applied in order to compare with the erosion under AC. Hot spot temperatures are used for comparative analysis of dry-band arcing severity on the tested materials. Also, depending on the type of filler,...
The paper investigates the repetitive fast pulse tests using IEC-TS 60034–18–42 as applied to 13.8 kV bar samples with two different stress grading systems: nonlinear resistive and capacitive. Insulated copper bars were furnished with a capacitive stress grading system consisting of aluminum foils embedded into the groundwall insulation forming a capacitively graded system. The effectiveness of the...
Nanomaterials have attracted considerable attention due to their unique physicochemical properties. However, agglomerations of nanofillers in nanocomposites have hindered the potential improvements to their properties. A novel technique of infusing nanosilica into silicone rubber with reduced agglomeration is reported in this paper. The technique involves electrospinning of silicone fibers, embedded...
The paper discusses the temperature profile along the stress grading and the conductive armor layers on the endwinding of a 13.8 kV motor coil when energized by repetitive fast pulse voltages such as pulse width modulated (PWM) voltages. The effect of the pulse rise time in the temperature profile at the end portion of the motor bar is also measured experimentally. The thermal stress due to two equivalent...
The successful application of polymeric materials for outdoor insulation depends primarily on the capability of materials to suppress surface leakage current leading to dry band arcing which causes tracking or erosion. The widely used materials, namely, silicone rubber, ethylene propylene diene monomer (EPDM) rubber and epoxy resins are all hydrophobic initially thus suppressing leakage current, but...
A new semiconductive glaze insulator with superior glaze and greatly improved contamination performance has been developed for use in vertical and V-string positions. This insulator makes it possible to convert many existing lines to operation at higher voltages and to design new lines with greatly reduced tower head dimensions.
The breakdown strength of liquids has been known to be highly dependent upon the dissolved water and air content, decreasing with increasing impurity levels. By means of the Kerr effect, it is shown that the static electric field distribution between parallel plate electrodes in chlorobiphenyls is dependent upon the impurity levels. Near breakdown however, the local cathode field strength remains...
A technique has been described as a possible tool in investigating the parameters which influence surface flashover. The technique has not as yet been fully evaluated, however, from initial observations, it appears to be very promising in contributing to the understanding of the mechanisms involved in surface flashover in liquids, a problem of great engineering importance.
It is common experience to observe a reduction in the insulating strength of an insulating liquid, when the space between the electrodes contains a solid insulating support extending between the electrodes. This has been found to be true regardless of the insulating medium and of the insulating support. Major difficulties are encountered in obtaining flashover data for the solid-liquid insulating...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.