Investigation into the influence of electrode material on the IEC Inclined Plane test procedure (IEC 60587) when applied for Direct Current (DC) voltages

Swinny, Raphael (2021-03)

Thesis (MEng)--Stellenbosch University, 2021.

Thesis

ENGLISH ABSTRACT: The inclined plane test (IPT) for testing the tracking and erosion resistance of polymer insulating materials is well established for AC conditions. Numerous researchers have used the standard AC test procedure and adapted it for DC application by applying both polarities of DC. Most researchers identify the amplitude and polarity of the applied DC voltage, conductivity and flow rate of contaminant, material properties of the samples under test, and erosion of the steel electrodes under DC energization as critical factors affecting the outcome of the tests. This research investigated the extent and effect of steel electrode erosion under DC energization, making use of the IEC 60587 test procedure, adapted for DC application. AC and DC inclined plane tests were conducted using standard steel electrodes as specified by IEC 60587. In addition, special carbon glass electrodes, with dimensions similar to that of the standard steel electrodes, were introduced into the test to ascertain whether this type of electrode material would eliminate/reduce the impact of steel electrode erosion. Tests were conducted at 4.5kV AC and ± DC, at a contaminant flow rate of 0.6 ml/min, using standard HTV Silicone Rubber samples with 51 % weight ATH filler. Results confirmed substantial erosion of the steel electrodes particularly under DC + energisation. The substitution of carbon glass for steel as an electrode material overcame the problem of electrode erosion, however tests conducted using the carbon glass electrodes were found to be much more aggressive in terms of material degradation. This is attributed to the reduced thermal conductivity of the carbon glass electrodes. Lastly, contaminant flow rate was found to be one of the biggest factors affecting the repeatability of the IPT, whether conducted under AC or DC.

AFRIKAANSE OPSOMMING: Die skuinsvlak-toets (inclined plane test ) vir die toets van die bestandheid van polimere wat as isoleermateriale gebruik word ten opsigte van spoorvorming en erosie is reeds goed gevestig vir wisselspanning (WS). Baie navorsers het die standaard WS-toetsprosedure aangepas en gebruik vir die toets met gelykspanning (GS) van albei polariteite. Die meeste navorsers het die amplitude en polariteit van die aangelegde GS-spanning, die konduktiwiteit en vloeitempo van die vloeistof, materiaal-eienskappe van die toetsmonsters en die erosie van die staal-elektrodes onder GS-spanning geïdentifiseer as kritiese faktore wat die toetsresultaat beïnvloed. Hierdie navorsing ondersoek die omvang en graad van die erosie van die staalelektrodes met GS-spanning deur die IEC 60587 toetsprosedure, aangepas vir GS, te gebruik. Die WS en GS skuinsvlaktoetse is uitgevoer met standaard staalelektrodes soos deur IEC 60587 gespesifiseer. Verder is koolstofglas-elektrodes met soortgelyke afmetings as die standaard staalelektrodes tydens die toets gebruik ten einde vas te stel of die materiaal-tipe die effek van staalektrodes uitskakel of verminder. Toetse is uitgevoer teen 4.5 kV WS en ± DC met ’n vloeitempo van 0.6 ml/min en standaard HTV silikoonrubber toetsmonsters met 51 % per gewig ATH-vuller. Die resultate het beduidende erosie van die staalelektrodes bevestig, veral met GS+ spanning. Die vervanging van die staalektrodes met koolstofglas het die probleem van die erosie van die elektrodes opgelos, maar dit is bevind dat die toetse met die glas elektrodes meer aggressiewe afbreking van die materiaal tot gevolg gehad het. Dit word toegeskryf aan die laer termiese konduktiwiteit van die koolstofglas elektrodes. Verder is bevind dat die vloeitempo van die kontaminant een van die belangrikste faktore is wat die herhaalbaarheid van WS- en GS-skuinsvlaktoetse is.

Please refer to this item in SUNScholar by using the following persistent URL: http://hdl.handle.net/10019.1/109891
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