Page 1. Monitoring the SF6 Pressure Level in Metal-Enclosed Switchgear to Detect Gas Leakages Luk... more Page 1. Monitoring the SF6 Pressure Level in Metal-Enclosed Switchgear to Detect Gas Leakages Lukas Graber1* and Manoj Kumar Pradhan2 1 ETH Zurich, Switzerland 2 University of Queensland, Australia *E-mail: lgraber@ieee.org ...
In the present work, a carefully designed experimental set up has been used to measure breakdown ... more In the present work, a carefully designed experimental set up has been used to measure breakdown voltages (BDV) of LN2 under realistic conditions which are likely to be encountered in the complex electrical systems in the field. Different electrode profiles viz. sphere-sphere, needle-plane has been used to simulate various practical conditions. The Authors particularly focuses on the breakdown characteristics of LN2 under composite voltages viz. AC superimposed with positive DC, AC superimposed with negative DC. It is observed that DC bias reduces the AC breakdown voltage considerably.
Inadvertent failure of power transformers has serious consequences on the system reliability, eco... more Inadvertent failure of power transformers has serious consequences on the system reliability, economics, and the revenue accrual. An accurate estimation of transformer life can, to a very large extent, mitigate the problems, besides satisfying the conflicting requirements of optimum utilization of the equipment and safeguarding the reliability. In this endeavour, the authors have planned long duration aging experiments on scaled-down
The degradation of electrical insulation in transformers is more often due to thermal stress. In ... more The degradation of electrical insulation in transformers is more often due to thermal stress. In this paper authors have attempted to work out a means of assessing the magnitude of temperature and the hottest region in the body of a large transformer with a reasonable degree of accuracy. A theoretical model has been developed based on boundary value problem of heat conduction in transformer winding using finite integral transform techniques. The model requires, in addition to electrical parameters of the transformer, information on the actual design data. The authors believe that this model predicts HST with precision and also indicates a possibility of on-line data acquisition.
In the recent past, a considerable amount of work has been published on the dynamics of aging of ... more In the recent past, a considerable amount of work has been published on the dynamics of aging of oil impregnated paper (OIP) insulation in transformers. The insulation is always subjected to stresses of different types at the same point in time. Among the more important stress are, electrical, thermal and their combination. Insulating properties of both solid (cellulose paper) and
Page 1. Monitoring the SF6 Pressure Level in Metal-Enclosed Switchgear to Detect Gas Leakages Luk... more Page 1. Monitoring the SF6 Pressure Level in Metal-Enclosed Switchgear to Detect Gas Leakages Lukas Graber1* and Manoj Kumar Pradhan2 1 ETH Zurich, Switzerland 2 University of Queensland, Australia *E-mail: lgraber@ieee.org ...
In the present work, a carefully designed experimental set up has been used to measure breakdown ... more In the present work, a carefully designed experimental set up has been used to measure breakdown voltages (BDV) of LN2 under realistic conditions which are likely to be encountered in the complex electrical systems in the field. Different electrode profiles viz. sphere-sphere, needle-plane has been used to simulate various practical conditions. The Authors particularly focuses on the breakdown characteristics of LN2 under composite voltages viz. AC superimposed with positive DC, AC superimposed with negative DC. It is observed that DC bias reduces the AC breakdown voltage considerably.
Inadvertent failure of power transformers has serious consequences on the system reliability, eco... more Inadvertent failure of power transformers has serious consequences on the system reliability, economics, and the revenue accrual. An accurate estimation of transformer life can, to a very large extent, mitigate the problems, besides satisfying the conflicting requirements of optimum utilization of the equipment and safeguarding the reliability. In this endeavour, the authors have planned long duration aging experiments on scaled-down
The degradation of electrical insulation in transformers is more often due to thermal stress. In ... more The degradation of electrical insulation in transformers is more often due to thermal stress. In this paper authors have attempted to work out a means of assessing the magnitude of temperature and the hottest region in the body of a large transformer with a reasonable degree of accuracy. A theoretical model has been developed based on boundary value problem of heat conduction in transformer winding using finite integral transform techniques. The model requires, in addition to electrical parameters of the transformer, information on the actual design data. The authors believe that this model predicts HST with precision and also indicates a possibility of on-line data acquisition.
In the recent past, a considerable amount of work has been published on the dynamics of aging of ... more In the recent past, a considerable amount of work has been published on the dynamics of aging of oil impregnated paper (OIP) insulation in transformers. The insulation is always subjected to stresses of different types at the same point in time. Among the more important stress are, electrical, thermal and their combination. Insulating properties of both solid (cellulose paper) and
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