Topic
Pressboard
About: Pressboard is a research topic. Over the lifetime, 1123 publications have been published within this topic receiving 9089 citations.
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TL;DR: In this article, the influence of clamping pressure relaxation and pressboard aging on windings' overall modal characteristics is studied, and the local vibration characteristics of conductors under hoop tension and axial bending are investigated.
Abstract: This study investigates the overall and local vibration characteristics of disk-type windings in power transformers. The influence of clamping pressure relaxation and pressboard aging on windings' overall modal characteristics is studied. Individual conductors in a winding can vibrate independently and have the local vibration from that of overall windings. The local vibration characteristics of conductors under hoop tension, axial bending and the loss of clamping pressure are investigated. It is found that the clamping pressure relaxation and pressboard aging lead to the decrease of natural frequencies but the faulty conductors result in the increasing number of natural frequencies.
4 citations
TL;DR: In this article, a pressure wave propagation (PWPP) method was used to study solid/liquid interfaces in still and flowing conditions with aluminum, brass, copper or pressboard in contact with demineralized water.
4 citations
Patent•
04 Dec 1996
TL;DR: In this paper, a honeycomb-shaped hollow bamboo pressboard made from the utility model has been proposed, which has the advantage that the strength of the pressboard is not affected, the dead weight of the pressing board is lightened, and the manufacturing cost and processing strength of a pressboard are reduced.
Abstract: The utility model provides a honeycomb-shaped hollow bamboo pressboard which comprises a bamboo pressboard of an upper layer and a bamboo pressboard of a lower layer and also comprises a hollow structure arranged between the bamboo pressboard of the upper layer and the bamboo pressboard of the lower layer, wherein the hollow structure is composed of a plurality of hexagonal hollow cylinder bodies which are mutually bonded to form a honeycomb-shaped hollow structure, and the stress distribution is of the hexagonal hollow cylinder bodies is optimum and rational; or a plurality of circular hollow cylinder bodies of which the stress distribution is good and the shape approximates to a hexagon are mutually bonded to form a honeycomb-shaped hollow structure. The bamboo pressboard made from the utility model has the advantages that the strength of the pressboard is not affected, the dead weight of the pressboard is lightened, and the manufacture cost and the processing strength of the pressboard are reduced. The utility model has the advantage of practicality.
4 citations
01 Jan 2015
TL;DR: In this article, a set of platform was built for partial discharge (PD) detection under AC and DC voltage, which was obtained by several tests and simulated by building physical model, and the experimental measurement and theoretical simulation results are the same: the pulse repetition frequency and PD amount decrease with the DC voltage increasing.
Abstract: In order to realize the fault diagnosis for converter transformer, to study the influence of ratios of AC and DC voltages on partial discharge(PD) characteristics has practical engineering significance for diagnosis of converter transformer. A set of platform was built for PD detection under AC and DC voltage. The relationship between ratios of AC and DC voltage and PD characteristics was obtained by several tests and simulated by building physical model. The experimental measurement and theoretical simulation results are the same: the pulse repetition frequency and PD amount decrease with the DC voltage increasing. But the PD inception voltage increases when DC voltage becomes larger. In addition, the PD phase moves form two locations to just one part in negative half cycle. So for converter transformer, the diagnosis basis should distinguish with the insulation problem at different location.
4 citations
31 Oct 2008
TL;DR: In this paper, the authors describe a novel dielectric diagnostic method ldquoDIRANArdQuo which features a fast measurement technique and an improved analysis algorithm for determining moisture in pressboard and paper of oil-paper-insulated transformers.
Abstract: This paper describes a novel dielectric diagnostic method ldquoDIRANArdquo which features a fast measurement technique and an improved analysis algorithm for determining moisture in pressboard and paper of oil-paper-insulated transformers. Dielectric response methods provide substantial advantages compared to moisture determination by oil sampling and conventional equilibrium diagrams, for example the influence of aging can be compensated and it is unnecessary to wait for moisture equilibrium. For the new instrument, the novel combination of time and frequency domain measurements substantially shortens the measurement time. The data analysis algorithm compares the measured dielectric properties of the actual power transformer to modeled dielectric properties. The software features a compensation for the influences of conductive aging by-products, which have similar dielectric properties as water. Without compensation the analyzed moisture content will be too high and may lead to unnecessary actions like drying. After moisture analysis, the new software categorizes the moisture concentration according to IEC 60422.
4 citations