Testing and diagnostics of medium-voltage cable insulation

Staranje kabelske izolacije je neizogiben proces ter je posledica termičnih obremenitev, obremenitev z električnim poljem in zunanjih vplivov med obratovalno dobo kabla. V želji, da bi izvedeli, v kakšnem stanju je in koliko časa bo kabel še primeren za obratovanje, so bile razvite razne preizkusne in kasneje tudi diagnostične metode, ki jih je možno izvajati na terenu. Slednjih se vedno bolj poslužujejo tudi v slovenskih elektrodistribucijskih podjetjih, od katerih ima pri tem vodilno vlogo Elektro Gorenjska. V teoretičnem delu naloge je poudarek na pregledu standardiziranih in uveljavljenih postopkov preizkušanja in diagnostike XLPE izolacije, ki jih je mogoče izvajati z njihovo merilno napravo TDM 45, izdelano v podjetju Megger. V praktičnem delu je bilo izvedenih več diagnostičnih meritev izgubnega faktorja in delnih razelektritev na njihovem SN kabelskem omrežju, čemur je sledila analiza rezultatov in predstavitev različno postaranih kablov.The aging of cable insulation is an inevitable process caused by thermal and electric loads, as well as by external influences during a cable\u27s service life. Various test and diagnostic methods that can be implemented on site have been developed to evaluate a cable\u27s condition and to predict its remaining service life. The above mentioned diagnostic methods are also increasingly used by electricity distribution companies in Slovenia. Among these the Elektro Gorenjska electricity distribution company plays the leading role in this segment. The theoretical part of this thesis focuses on examining some of the established standardized testing and diagnostic procedures of XLPE insulation. All these procedures can be carried out by implementing Megger’s TDM 45 measuring device. In the practical part, several diagnostic measurements of the loss factor and PD were carried out on their MV cable network, followed by the analysis of the results and the presentation of differently aged cables