https://hvwiki.cuvotest.com/api.php?action=feedcontributions&user=Expert&feedformat=atomHVwiki - User contributions [en]2024-03-29T06:22:45ZUser contributionsMediaWiki 1.28.3https://hvwiki.cuvotest.com/index.php?title=VPI&diff=129VPI2018-11-25T20:10:27Z<p>Expert: </p>
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<div>[[Vacuum Pressure Impregnation]]</div>Experthttps://hvwiki.cuvotest.com/index.php?title=Leakage_Current&diff=128Leakage Current2018-10-07T20:56:27Z<p>Expert: Created page with "Current, that can be measured versus gound once a insulation specimen or an equiptment is connected with high voltage an ground potential."</p>
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<div>Current, that can be measured versus gound once a insulation specimen or an equiptment is connected with high voltage an ground potential.</div>Experthttps://hvwiki.cuvotest.com/index.php?title=Guard_Ring_Electrode&diff=127Guard Ring Electrode2018-10-07T20:53:08Z<p>Expert: Created page with "The application of a guard ring electrode is to suppress the effect of surface currents when actually trying to determine the current through an insulation test sample. Due to..."</p>
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<div>The application of a guard ring electrode is to suppress the effect of surface currents when actually trying to determine the current through an insulation test sample. Due to different effects such as moisture, the surface current is easily one magnitude higher than the latter one.<br />
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The general setup would consist of a plane-plane arrangement, where the ground electrode consists of two separated concentric metal parts insulated from each other. The outer guard ring electrode is connected to ground potential. The inner measuring electrode is connected to an electrometer.<br />
Fig. x<br />
General setup<br />
Fig. y<br />
Stator bar specimen with prepared guard ring electrodes for IR and TanD measurement.<br />
<br />
IN IEC 60093<br />
DIN IEC 62631<br />
ISO 21178</div>Experthttps://hvwiki.cuvotest.com/index.php?title=Frequency_Response_Analysis&diff=126Frequency Response Analysis2018-05-30T20:15:20Z<p>Expert: Created page with "Frequency Response Analysis is used to detect geometric changes of the active part of high voltage device such as an transformer. Characterizes the RLC network of conductor r..."</p>
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<div>Frequency Response Analysis is used to detect geometric changes of the active part of high voltage device such as an transformer.<br />
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Characterizes the RLC network of conductor resistance, winding inductance and stray capacities<br />
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Frequency variable source<br />
Current amplitude and phase measurement <br />
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Fingerprint <br />
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[[Bode Diagram]]</div>Experthttps://hvwiki.cuvotest.com/index.php?title=SFRA&diff=125SFRA2018-05-30T20:10:04Z<p>Expert: </p>
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<div>Sweeping [[Frequency Response Analysis]]</div>Experthttps://hvwiki.cuvotest.com/index.php?title=SFRA&diff=124SFRA2018-05-30T20:09:54Z<p>Expert: Created page with "Sweeping Frequenz Response Analysis"</p>
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<div>Sweeping [[Frequenz Response Analysis]]</div>Experthttps://hvwiki.cuvotest.com/index.php?title=FRA&diff=123FRA2018-05-30T20:09:18Z<p>Expert: Created page with "Frequency Response Analysis"</p>
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<div>[[Frequency Response Analysis]]</div>Experthttps://hvwiki.cuvotest.com/index.php?title=Partial_Discharge&diff=122Partial Discharge2018-05-17T13:44:01Z<p>Expert: </p>
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<div>A partial discharge (PD) is a local and in the case of fluid dielectrics also temporary loss in dielectric strength.<br />
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There are two major types<br />
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'''Outer partial discharges'''<br />
<br />
occur near an electrode within a fluid (gaseous or liquid) dielectric medium<br />
<br />
examples:<br />
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[[Partial Discharges at Tip Electrode in Air]]<br />
corona, streamer or leader in air<br />
streamer or leader in oil or ester<br />
<br />
typical PD patterns<br />
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'''Inner partial discharges'''<br />
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occur near or with a solid dielectric medium<br />
<br />
examples:<br />
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[[Inner Partial Discharge in a Gas filled Void ]] within a resin<br />
slide discharge along the interface of two dielectric media of different aggregate state<br />
coupling discharges between two electrodes of a defined and a free potential<br />
defect near electrode</div>Experthttps://hvwiki.cuvotest.com/index.php?title=Thermal_Breakdown&diff=121Thermal Breakdown2018-04-29T22:01:21Z<p>Expert: Created page with "A thermal breakdown usual occurs in solid insulators, due to the less capability to transport or dissipate heat respectively. If thermal losses are higher than the dissipated..."</p>
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<div>A thermal breakdown usual occurs in solid insulators, due to the less capability to transport or dissipate heat respectively.<br />
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If thermal losses are higher than the dissipated thermal current, the insulator is getting warmer and a thermal breakdown most likely to occur.</div>Experthttps://hvwiki.cuvotest.com/index.php?title=Inner_Partial_Discharge_in_a_Gas_filled_Void&diff=120Inner Partial Discharge in a Gas filled Void2018-04-29T21:07:39Z<p>Expert: </p>
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<div>The initial field strength distribution in a gas solid insulation system is determined by the ratio of [[relative dielectric constant]]s of the two dielectric materials. <br />
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Standard insulating gases always do have an relative dielectric constant of e_r=1. If molecules were polar, the resulting forces would turn them into liquids. Typical cast or impregnation resins as well as their composites with solid fillers have a e_r~4.<br />
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For this reason a gas void is loaded by a about four times higher field strength than the solid resin.<br />
<br />
Fig 1 illustrates the situation for the case that no partial discharges occur.<br />
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If the inner dielectric strength E_i of the void is exceeded or the [[Paschen's Law]] is fulfilled respectively a discharge can occur. Since for AC voltage in general the highest field strength stress occurs at the voltage peak, a first PD will occur most likely at the 90 or 270° phase angle of the AC voltage period. The global field strength and the field strength resulting out of the space charge will add up vectorial. <br />
In any case the resulting field strength within the void will be significantly less. Depending on the magnitude of the discharge the qualitative field strength distribution is as follows - Fig 2.<br />
<br />
In general space charges stick minutes or rather hours to a solid surface, since it is energetically a more stable status - see: [[Electronic Band Structure]]. Due to their local separation the charges do not recombine either. Therefore also the field strength dE_PD resulting out of the charge separation by the PD remains effective, independent of the following change of voltage and therefore global field strength. Depending on the nominal magnitude of the previous PD E_i of opposite polarity will be exceeded at an more early phase angle for a higher PD charge magnitude and a relatively late phase angle for a lower PD charge.<br />
<br />
This depiction explains the phase angle of the typical phase resolved histogram for inner partials discharges of voids.</div>Experthttps://hvwiki.cuvotest.com/index.php?title=Inner_Partial_Discharge_in_a_Gas_filled_Void&diff=119Inner Partial Discharge in a Gas filled Void2018-04-29T17:05:22Z<p>Expert: </p>
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<div>The initial field strength distribution in a gas solid insulation system is determined by the ratio of [[relative dielectric constant]]s of the two dielectric materials. <br />
<br />
Standard insulating gases always do have an relative dielectric constant of e_r=1. If molecules were polar, the resulting forces would turn them into liquids. Typical cast or impregnation resins as well as their composites with solid fillers have a e_r~4.<br />
<br />
For this reason a gas void is loaded by a about four times higher field strength than the solid resin.<br />
<br />
Fig 1 illustrates the situation for the case that no partial discharges occur.<br />
<br />
If the inner dielectric strength E_i of the voids is exceeded an discharge can occur. Since for AC voltage the highest field strength stress occurs at the voltage peak, a first PD will also most likely at this point of AC period. Depending on the magnitude of this first discharge the qualitative field strength distribution is as follows - Fig 2<br />
<br />
For space charges stick minutes or hours to a solid, the charges of the elapsed PD will also remain at their location until a high field strength will forced them to do <br />
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space charge based explanation for phenomena and respectively the phase histogram.</div>Experthttps://hvwiki.cuvotest.com/index.php?title=Main_Page&diff=118Main Page2018-04-28T18:39:03Z<p>Expert: </p>
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<div>Dear High Voltage student, engineer, enthusiast,<br />
<br />
with this HVwiki I would like to publish a small compendium on High Voltage technology.<br />
I would be happy if you take the time to give me feedback or even recommendation for improvements.<br />
<br />
Please feel invited to use the 'Random page' link!<br />
<br />
Kind regards,<br><br />
Dr.-Ing. Karsten Backhaus</div>Experthttps://hvwiki.cuvotest.com/index.php?title=File:Coaxial_cylinders.svg&diff=117File:Coaxial cylinders.svg2018-04-27T05:49:05Z<p>Expert: </p>
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<div></div>Experthttps://hvwiki.cuvotest.com/index.php?title=Coaxial_Cylinders&diff=116Coaxial Cylinders2018-04-27T05:45:30Z<p>Expert: </p>
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<div>The field strength distribution between two coaxial cylinders can be determinde analytically by<br />
<br />
[[file:coaxial_cylinders.svg]]</div>Experthttps://hvwiki.cuvotest.com/index.php?title=Coaxial_Cylinders&diff=115Coaxial Cylinders2018-04-27T05:45:07Z<p>Expert: </p>
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<div>The field strength distribution between two coaxial cylinders can be determinde analytically by<br />
<br />
[[coaxial_cylinders.svg]]</div>Experthttps://hvwiki.cuvotest.com/index.php?title=Coaxial_Cylinders&diff=114Coaxial Cylinders2018-04-27T05:42:35Z<p>Expert: </p>
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<div>The field strength distribution between two coaxial cylinders can be determinde analytically by<br />
<br />
<math> a^2 + b^2 = c^2 </math><br />
<br />
[[File:coaxial_cylinders.svg]]</div>Experthttps://hvwiki.cuvotest.com/index.php?title=File:Unbenannt_5.svg&diff=112File:Unbenannt 5.svg2018-04-26T19:23:42Z<p>Expert: </p>
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<div></div>Experthttps://hvwiki.cuvotest.com/index.php?title=Corona_Losses&diff=111Corona Losses2018-04-26T06:49:10Z<p>Expert: </p>
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<div>[[Overhead Lines]] may have [[Corona]] Losses<br />
<br />
x W/m</div>Experthttps://hvwiki.cuvotest.com/index.php?title=Corona_Losses&diff=110Corona Losses2018-04-26T06:47:05Z<p>Expert: Created page with "Overhead Lines may have Corona Losses x W/m"</p>
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<div>[[Overhead Lines]] may have Corona Losses<br />
<br />
x W/m</div>Experthttps://hvwiki.cuvotest.com/index.php?title=File:LI.png&diff=109File:LI.png2018-04-25T12:50:38Z<p>Expert: Expert uploaded a new version of File:LI.png</p>
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<div></div>Experthttps://hvwiki.cuvotest.com/index.php?title=File:LI.png&diff=108File:LI.png2018-04-25T12:48:12Z<p>Expert: Expert uploaded a new version of File:LI.png</p>
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<div></div>Experthttps://hvwiki.cuvotest.com/index.php?title=File:LI.png&diff=106File:LI.png2018-04-25T12:20:34Z<p>Expert: </p>
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<div></div>Experthttps://hvwiki.cuvotest.com/index.php?title=Lightning_Impulse&diff=105Lightning Impulse2018-04-25T12:18:17Z<p>Expert: </p>
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<div>standard impulse test <br />
rise time T1: 1.2 µ, Time to halfe value 50 µs<br />
[[File:LI.png]]<br />
<br />
Lightning Impulses are usually generated by a [[Marx-Generator]].</div>Experthttps://hvwiki.cuvotest.com/index.php?title=Rise_Time_-_Bandwidth_-_Correlation&diff=104Rise Time - Bandwidth - Correlation2018-04-23T15:39:02Z<p>Expert: Created page with "A measurement circuit is assumed or approximated to behave like a simple RC-integrator. The time constant will then be: τ=RC The bandwidth is then BW=1/(2*π*RC)=1/(2*π*τ)..."</p>
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<div>A measurement circuit is assumed or approximated to behave like a simple RC-integrator.<br />
The time constant will then be: τ=RC<br />
<br />
The bandwidth is then BW=1/(2*π*RC)=1/(2*π*τ)<br />
<br />
On the other hand, the rise time for this simple RC circuit is calculated starting from the equation of the voltage across the cap when a step impulse is applied at the input:<br />
u(t)=U*(1-exp(-t/τ))<br />
<br />
For u(t)=0.1U you get 0.1U=U*(1-exp(-t10/τ)), where t10 is the time when the voltage reaches 10% of the final value.<br />
<br />
After simplification<br />
0.9=exp(-t10/τ)<br />
<br />
Applying the natural log to the equation you get:<br />
ln0.9=-t10/τ or t10=-τ*ln0.9<br />
<br />
Similarly, for u(t)=0.9U, we have t90=-τ*ln0.1<br />
<br />
The rise time is then:<br />
tr=t90-t10=τ*(ln0.9-ln0.1)≈2.2*τ or τ=tr/2.2<br />
<br />
Substitute this value of τ into the expression for bandwidth:<br />
BW=1/(2*π*tr/(2.2))=2.2/(2*π*tr)≈0.35/tr<br />
<br />
or<br />
<br />
BW*tr≈0.35</div>Experthttps://hvwiki.cuvotest.com/index.php?title=OCP&diff=103OCP2018-04-23T14:36:41Z<p>Expert: </p>
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<div>[[Outer Corona Protection]]</div>Experthttps://hvwiki.cuvotest.com/index.php?title=FFT&diff=102FFT2018-04-23T14:36:13Z<p>Expert: Created page with "Fast Fourier Transformation"</p>
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<div>[[Fast Fourier Transformation]]</div>Experthttps://hvwiki.cuvotest.com/index.php?title=Delaminiation_Defect&diff=101Delaminiation Defect2018-04-23T14:35:11Z<p>Expert: Created page with "In layered insulation systems delamination defects may occure, when the thermo-mechanical stress exceeds the strength of the insulation. PD Pattern"</p>
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<div>In layered insulation systems delamination defects may occure, when the thermo-mechanical stress exceeds the strength of the insulation.<br />
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PD Pattern</div>Experthttps://hvwiki.cuvotest.com/index.php?title=VPI&diff=100VPI2018-04-23T14:32:55Z<p>Expert: </p>
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<div>[[Vaccum Pressure Impregnation]]</div>Experthttps://hvwiki.cuvotest.com/index.php?title=Resin_Rich_Insulation&diff=99Resin Rich Insulation2018-04-23T14:32:27Z<p>Expert: Created page with "Procedure to produce a solid insulation for electrical machines in general."</p>
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<div>Procedure to produce a solid insulation for electrical machines in general.</div>Experthttps://hvwiki.cuvotest.com/index.php?title=Coaxial_Cylinders&diff=98Coaxial Cylinders2018-04-20T22:35:46Z<p>Expert: </p>
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<div>The field strength distribution between two coaxial cylinders can be determinde analytically by<br />
<br />
<math> a^2 + b^2 = c^2 </math><br />
<br />
[[File:Coaxial cylinders.svg]]</div>Experthttps://hvwiki.cuvotest.com/index.php?title=Coaxial_Cylinders&diff=96Coaxial Cylinders2018-04-20T22:22:48Z<p>Expert: </p>
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<div>The field strength distribution between two coaxial cylinders can be determinde analytically by<br />
<br />
<math> a^2 + b^2 = c^2 </math></div>Experthttps://hvwiki.cuvotest.com/index.php?title=Main_Page&diff=95Main Page2018-04-19T21:18:43Z<p>Expert: </p>
<hr />
<div>Dear High Voltage student, engineer, enthusiast,<br />
<br />
with this HVwiki I would like to publish a small compendium on High Voltage technology.<br />
I would be happy if you take the time to give me feedback or even recommendation for improvements.<br />
<br />
Please feel invited to use the 'Random page' link!<br />
<br />
Kind regards,<br><br />
Dr.-Ing. Karsten Backhaus<br />
<br />
<br />
<br />
<br />
<br />
<br />
'''MediaWiki has been successfully installed.'''<br />
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Consult the [http://meta.wikimedia.org/wiki/Help:Contents User's Guide] for information on using the wiki software.<br />
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* [http://www.mediawiki.org/wiki/Manual:FAQ MediaWiki FAQ]<br />
* [https://lists.wikimedia.org/mailman/listinfo/mediawiki-announce MediaWiki release mailing list]</div>Experthttps://hvwiki.cuvotest.com/index.php?title=Main_Page&diff=94Main Page2018-04-19T21:18:26Z<p>Expert: </p>
<hr />
<div>Dear High Voltage student, engineer, enthusiast,<br />
<br />
with this HVwiki I would like to publish a small compendium on High Voltage technology.<br />
I would be happy if you take the time to give me feedback or even recommendation for improvements.<br />
<br />
Please feel invited to use the 'Random page' link!<br />
<br />
Kind regards,<br />
Dr.-Ing. Karsten Backhaus<br />
<br />
<br />
<br />
<br />
<br />
<br />
'''MediaWiki has been successfully installed.'''<br />
<br />
Consult the [http://meta.wikimedia.org/wiki/Help:Contents User's Guide] for information on using the wiki software.<br />
<br />
== Getting started ==<br />
* [http://www.mediawiki.org/wiki/Manual:Configuration_settings Configuration settings list]<br />
* [http://www.mediawiki.org/wiki/Manual:FAQ MediaWiki FAQ]<br />
* [https://lists.wikimedia.org/mailman/listinfo/mediawiki-announce MediaWiki release mailing list]</div>Experthttps://hvwiki.cuvotest.com/index.php?title=High_Voltage&diff=93High Voltage2018-04-19T21:13:17Z<p>Expert: Created page with "U > 1000 V"</p>
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<div>U > 1000 V</div>Experthttps://hvwiki.cuvotest.com/index.php?title=HV&diff=92HV2018-04-19T21:13:03Z<p>Expert: Created page with "High Voltage"</p>
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<div>[[High Voltage]]</div>Experthttps://hvwiki.cuvotest.com/index.php?title=LDPE&diff=91LDPE2018-04-19T21:12:27Z<p>Expert: Created page with "Low Density Polyethylene"</p>
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<div>Low Density [[Polyethylene]]</div>Experthttps://hvwiki.cuvotest.com/index.php?title=HDPE&diff=90HDPE2018-04-19T21:12:04Z<p>Expert: Created page with "High Density Polyethylene"</p>
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<div>High Density [[Polyethylene]]</div>Experthttps://hvwiki.cuvotest.com/index.php?title=SiC&diff=89SiC2018-04-19T21:11:22Z<p>Expert: Created page with "Silicone Carbid"</p>
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<div>[[Silicone Carbid]]</div>Experthttps://hvwiki.cuvotest.com/index.php?title=ECP&diff=88ECP2018-04-19T21:10:53Z<p>Expert: Created page with "End Corona Protection"</p>
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<div>[[End Corona Protection]]</div>Experthttps://hvwiki.cuvotest.com/index.php?title=OCP&diff=87OCP2018-04-19T21:10:32Z<p>Expert: Created page with "Outer Cornona Protection"</p>
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<div>[[Outer Cornona Protection]]</div>Experthttps://hvwiki.cuvotest.com/index.php?title=VPI&diff=86VPI2018-04-19T21:09:57Z<p>Expert: Created page with "Vaccum Pressure Imprenation"</p>
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<div>[[Vaccum Pressure Imprenation]]</div>Experthttps://hvwiki.cuvotest.com/index.php?title=SIR&diff=85SIR2018-04-19T21:09:17Z<p>Expert: Created page with "Silicone Rubber"</p>
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<div>[[Silicone Rubber]]</div>Experthttps://hvwiki.cuvotest.com/index.php?title=Polytetrafluoroethylene&diff=84Polytetrafluoroethylene2018-04-19T21:06:28Z<p>Expert: Created page with "Polytetrafluoroethylene *lowest dielectric constant of solid insulation materials"</p>
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<div>Polytetrafluoroethylene<br />
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*lowest dielectric constant of solid insulation materials</div>Experthttps://hvwiki.cuvotest.com/index.php?title=PTFE&diff=83PTFE2018-04-19T21:05:57Z<p>Expert: Created page with "Polytetrafluoroethylene"</p>
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<div>[[Polytetrafluoroethylene]]</div>Experthttps://hvwiki.cuvotest.com/index.php?title=Hetero_Charge&diff=82Hetero Charge2018-04-19T21:00:16Z<p>Expert: Created page with "Hetero charges are space charges or charge carrieres respectively that have an oposite charge compared with an electrode in its vincinity. Due to the different polarity of the..."</p>
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<div>Hetero charges are space charges or charge carrieres respectively that have an oposite charge compared with an electrode in its vincinity.<br />
Due to the different polarity of the electrode an the hetero charge the effectiv fieldstrength is raised be the hetero charge.<br />
<br />
Figure:</div>Experthttps://hvwiki.cuvotest.com/index.php?title=Homo_Charge&diff=81Homo Charge2018-04-19T20:57:40Z<p>Expert: </p>
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<div>Homo Charges are space charges or charge carriers with the same polarity as an electrode in its vincinty.<br />
Usually a elctrode injects homo charges.<br />
Due to the same polarity of the homo charge and the injecting electrode the effectiv field strength in the interface of metal electrode and insulator is lowered.<br />
<br />
Figure:</div>Experthttps://hvwiki.cuvotest.com/index.php?title=Homo_Charge&diff=80Homo Charge2018-04-19T20:57:20Z<p>Expert: Created page with "Homo Charges are space charges or charge carriers with the same polarity as an electrode in its vincinty. Usually a elctrode injects homo charges. Due to the same polarity of..."</p>
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<div>Homo Charges are space charges or charge carriers with the same polarity as an electrode in its vincinty.<br />
Usually a elctrode injects homo charges.<br />
Due to the same polarity of the homo charge and the injecting electrode the effectiv field strength in the interface of metal electrode and insulator is lowered.</div>Experthttps://hvwiki.cuvotest.com/index.php?title=GIL&diff=79GIL2018-04-19T18:17:58Z<p>Expert: Created page with "Gas-Insulated Line"</p>
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<div>[[Gas-Insulated Line]]</div>Experthttps://hvwiki.cuvotest.com/index.php?title=Coaxial_Cylinders&diff=78Coaxial Cylinders2018-04-19T13:36:09Z<p>Expert: </p>
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<div>The field strength distribution between two coaxial cylinders can be determinde analytically by<br />
<br />
:<math> a^2 + b^2 = c^2 </math></div>Experthttps://hvwiki.cuvotest.com/index.php?title=Coaxial_Cylinders&diff=77Coaxial Cylinders2018-04-19T13:31:20Z<p>Expert: Created page with "The field strength distribution between two coaxial cylinders can be determinde analytically by <math> a^2 + b^2 = c^2 </math>"</p>
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<div>The field strength distribution between two coaxial cylinders can be determinde analytically by<br />
<br />
<math> a^2 + b^2 = c^2 </math></div>Expert