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You searched for subject:(onset voltage). Showing records 1 – 3 of 3 total matches.

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Queensland University of Technology

1. Hinde, David Derek. Corona discharges on the surfaces of high voltage composite insulators.

Degree: 2009, Queensland University of Technology

The degradation of high voltage electrical insulation is a prime factor that can significantly influence the reliability performance and the costs of maintaining high voltage electricity networks. Little information is known about the system of localized degradation from corona discharges on the relatively new silicone rubber sheathed composite insulators that are now being widely used in high voltage applications. This current work focuses on the fundamental principles of electrical corona discharge phenomena to provide further insights to where damaging surface discharges may localize and examines how these discharges may degrade the silicone rubber material. Although water drop corona has been identified by many authors as a major cause of deterioration of silicone rubber high voltage insulation until now no thorough studies have been made of this phenomenon. Results from systematic measurements taken using modern digital instrumentation to simultaneously record the discharge current pulses and visible images associated with corona discharges from between metal electrodes, metal electrodes and water drops, and between waters drops on the surface of silicone rubber insulation, using a range of 50 Hz voltages are inter compared. Visual images of wet electrodes show how water drops can play a part in encouraging flashover, and the first reproducible visual images of water drop corona at the triple junction of water air and silicone rubber insulation are presented. A study of the atomic emission spectra of the corona produced by the discharge from its onset up to and including spark-over, using a high resolution digital spectrometer with a fiber optic probe, provides further understanding of the roles of the active species of atoms and molecules produced by the discharge that may be responsible for not only for chemical changes of insulator surfaces, but may also contribute to the degradation of the metal fittings that support the high voltage insulators. Examples of real insulators and further work specific to the electrical power industry are discussed. A new design concept to prevent/reduce the damaging effects of water drop corona is also presented.

Subjects/Keywords: corona discharges; discharge current; onset voltage; point-plane; repetition rate; Trichel pulse; emission spectra; silicone rubber; water drop corona; high voltage insulators

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Hinde, D. D. (2009). Corona discharges on the surfaces of high voltage composite insulators. (Thesis). Queensland University of Technology. Retrieved from https://eprints.qut.edu.au/29320/

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16th Edition):

Hinde, David Derek. “Corona discharges on the surfaces of high voltage composite insulators.” 2009. Thesis, Queensland University of Technology. Accessed January 27, 2020. https://eprints.qut.edu.au/29320/.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7th Edition):

Hinde, David Derek. “Corona discharges on the surfaces of high voltage composite insulators.” 2009. Web. 27 Jan 2020.

Vancouver:

Hinde DD. Corona discharges on the surfaces of high voltage composite insulators. [Internet] [Thesis]. Queensland University of Technology; 2009. [cited 2020 Jan 27]. Available from: https://eprints.qut.edu.au/29320/.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Hinde DD. Corona discharges on the surfaces of high voltage composite insulators. [Thesis]. Queensland University of Technology; 2009. Available from: https://eprints.qut.edu.au/29320/

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation


Indian Institute of Science

2. Chatterjee, Sreenita. Dimensioning Of Corona Control Rings For EHV/UHV Line Hardware And Substations.

Degree: 2012, Indian Institute of Science

High voltage (EHV and UHV) transmission facilitates transfer of large amount of power over long distances. However, due to the inherent geometry, the line and substation hardware of EHV and UHV class generate high electric fields, which results in local ionisation of air called corona discharges. Apart from producing audible noise in the form of frying or hissing sound, corona produces significant electromagnetic interferences in the radio range. The limit for this corona generated Radio Interference (RI) has been stipulated by international standards, which are strictly to be followed. In line and substation hardware, corona control rings are generally employed to limit or avoid corona. Standard dimensions of corona rings are not available for EHV and UHV class. In most of the cases, their design is based on either a trial and error method or based on empirical extrapolation. Only in certain specific cases, the dimensioning of the rings is carried out using electric field calculations. In any of these approaches, the unavoidable surface abrasions, which can lead to corona, are not considered. There are also efforts to account for nominal surface irregularity by using a surface roughness factor, which is highly heuristic. In order to address this practically relevant problem, the present work was taken up. The intended exercise requires accurate field computation and a suitable criterion for checking corona onset. For the first part, the Surface Charge Simulation Method is adopted with newly proposed sub-modelling technique. The surface of the toroid is discretised into curvilinear patches with linear approximation for the surface charge density. Owing to its high accuracy, Galerkin’s method of moments formulation is employed. The problem of singularity encountered in the numerical approach is handled using a method based on Duffy’s transformation. The developed codes have also been validated with standard geometries. After a survey of relevant literature the ‘Critical Avalanche Criteria’ is chosen for its simplicity and applicability to the problem. Through a detailed simulation, the effect of avalanche space charge in reducing the corona onset voltage is found to be around 1.5% and hence it is not considered further. For utilities not interested in a detailed calculation procedure for dimensioning of corona rings, design curves are developed for circular corona rings of both 400 kV and 765 kV class with surface roughness factor in the range 0.8 – 1. In the second part of the work, a methodology for dimensioning is developed wherein the inevitable surface abrasion in the form of minute protrusions can be accounted. It is first shown that even though considerable field intensification occurs at the protrusions, such localised modification need not lead to corona. It is shown that by varying the minor radius of the corona ring, it is possible to get a design where the prescribed surface abrasion does not lead to corona onset. In summary, the present work has successfully developed a reliable methodology for the… Advisors/Committee Members: Kumar, Udaya.

Subjects/Keywords: Electric Power Transmission; High Voltages; Extra High Voltage (EHV); Ultra High Voltage (UHV); High Voltage Transmission; Corona (Electricity); Corona Control Rings; Electric Fields - Numerical Computation; Corona Rings; Corona Onset; Visual Electrical Discharge; Radio Interference (RI); Visual Electric Discharge; Electrical Engineering

Record DetailsSimilar RecordsGoogle PlusoneFacebookTwitterCiteULikeMendeleyreddit

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Chatterjee, S. (2012). Dimensioning Of Corona Control Rings For EHV/UHV Line Hardware And Substations. (Thesis). Indian Institute of Science. Retrieved from http://hdl.handle.net/2005/2446

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16th Edition):

Chatterjee, Sreenita. “Dimensioning Of Corona Control Rings For EHV/UHV Line Hardware And Substations.” 2012. Thesis, Indian Institute of Science. Accessed January 27, 2020. http://hdl.handle.net/2005/2446.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7th Edition):

Chatterjee, Sreenita. “Dimensioning Of Corona Control Rings For EHV/UHV Line Hardware And Substations.” 2012. Web. 27 Jan 2020.

Vancouver:

Chatterjee S. Dimensioning Of Corona Control Rings For EHV/UHV Line Hardware And Substations. [Internet] [Thesis]. Indian Institute of Science; 2012. [cited 2020 Jan 27]. Available from: http://hdl.handle.net/2005/2446.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Chatterjee S. Dimensioning Of Corona Control Rings For EHV/UHV Line Hardware And Substations. [Thesis]. Indian Institute of Science; 2012. Available from: http://hdl.handle.net/2005/2446

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation


Indian Institute of Science

3. Chatterjee, Sreenita. Dimensioning Of Corona Control Rings For EHV/UHV Line Hardware And Substations.

Degree: 2012, Indian Institute of Science

High voltage (EHV and UHV) transmission facilitates transfer of large amount of power over long distances. However, due to the inherent geometry, the line and substation hardware of EHV and UHV class generate high electric fields, which results in local ionisation of air called corona discharges. Apart from producing audible noise in the form of frying or hissing sound, corona produces significant electromagnetic interferences in the radio range. The limit for this corona generated Radio Interference (RI) has been stipulated by international standards, which are strictly to be followed. In line and substation hardware, corona control rings are generally employed to limit or avoid corona. Standard dimensions of corona rings are not available for EHV and UHV class. In most of the cases, their design is based on either a trial and error method or based on empirical extrapolation. Only in certain specific cases, the dimensioning of the rings is carried out using electric field calculations. In any of these approaches, the unavoidable surface abrasions, which can lead to corona, are not considered. There are also efforts to account for nominal surface irregularity by using a surface roughness factor, which is highly heuristic. In order to address this practically relevant problem, the present work was taken up. The intended exercise requires accurate field computation and a suitable criterion for checking corona onset. For the first part, the Surface Charge Simulation Method is adopted with newly proposed sub-modelling technique. The surface of the toroid is discretised into curvilinear patches with linear approximation for the surface charge density. Owing to its high accuracy, Galerkin’s method of moments formulation is employed. The problem of singularity encountered in the numerical approach is handled using a method based on Duffy’s transformation. The developed codes have also been validated with standard geometries. After a survey of relevant literature the ‘Critical Avalanche Criteria’ is chosen for its simplicity and applicability to the problem. Through a detailed simulation, the effect of avalanche space charge in reducing the corona onset voltage is found to be around 1.5% and hence it is not considered further. For utilities not interested in a detailed calculation procedure for dimensioning of corona rings, design curves are developed for circular corona rings of both 400 kV and 765 kV class with surface roughness factor in the range 0.8 – 1. In the second part of the work, a methodology for dimensioning is developed wherein the inevitable surface abrasion in the form of minute protrusions can be accounted. It is first shown that even though considerable field intensification occurs at the protrusions, such localised modification need not lead to corona. It is shown that by varying the minor radius of the corona ring, it is possible to get a design where the prescribed surface abrasion does not lead to corona onset. In summary, the present work has successfully developed a reliable methodology for the… Advisors/Committee Members: Kumar, Udaya.

Subjects/Keywords: Electric Power Transmission; High Voltages; Extra High Voltage (EHV); Ultra High Voltage (UHV); High Voltage Transmission; Corona (Electricity); Corona Control Rings; Electric Fields - Numerical Computation; Corona Rings; Corona Onset; Visual Electrical Discharge; Radio Interference (RI); Visual Electric Discharge; Electrical Engineering

Record DetailsSimilar RecordsGoogle PlusoneFacebookTwitterCiteULikeMendeleyreddit

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Chatterjee, S. (2012). Dimensioning Of Corona Control Rings For EHV/UHV Line Hardware And Substations. (Thesis). Indian Institute of Science. Retrieved from http://etd.iisc.ernet.in/handle/2005/2446 ; http://etd.ncsi.iisc.ernet.in/abstracts/3158/G25440-Abs.pdf

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16th Edition):

Chatterjee, Sreenita. “Dimensioning Of Corona Control Rings For EHV/UHV Line Hardware And Substations.” 2012. Thesis, Indian Institute of Science. Accessed January 27, 2020. http://etd.iisc.ernet.in/handle/2005/2446 ; http://etd.ncsi.iisc.ernet.in/abstracts/3158/G25440-Abs.pdf.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7th Edition):

Chatterjee, Sreenita. “Dimensioning Of Corona Control Rings For EHV/UHV Line Hardware And Substations.” 2012. Web. 27 Jan 2020.

Vancouver:

Chatterjee S. Dimensioning Of Corona Control Rings For EHV/UHV Line Hardware And Substations. [Internet] [Thesis]. Indian Institute of Science; 2012. [cited 2020 Jan 27]. Available from: http://etd.iisc.ernet.in/handle/2005/2446 ; http://etd.ncsi.iisc.ernet.in/abstracts/3158/G25440-Abs.pdf.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Chatterjee S. Dimensioning Of Corona Control Rings For EHV/UHV Line Hardware And Substations. [Thesis]. Indian Institute of Science; 2012. Available from: http://etd.iisc.ernet.in/handle/2005/2446 ; http://etd.ncsi.iisc.ernet.in/abstracts/3158/G25440-Abs.pdf

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

.