Naprezanja izolacije elektroenergetske opreme pri nestandardnim talasnim oblicima prenapona

Ranko Jasika; Jovan Mrvić; Stefan  Obradović

doi:10.5937/zeint32-41430

Ranko Jasika Univerzitet u Beogradu, Elektrotehnički institut "Nikola Tesla" https://orcid.org/0000-0002-6593-4117
Jovan Mrvić Univerzitet u Beogradu, Elektrotehnički institut "Nikola Tesla" https://orcid.org/0000-0001-6964-6350
Stefan Obradović Univerzitet u Beogradu, Elektrotehnički institut "Nikola Tesla"

DOI: https://doi.org/10.5937/zeint32-41430

Ključne reči: koordinacija izolacije, ATP/EMTP, prenaponi, FDSF, Furijeova transformacija, frekventni domen

Sažetak

Elektroenergetska oprema je tokom svog rada stalno izložena prenaponima različitog porekla, kao što su atmosferska pražnjenja, sklopne operacije, kvarovi itd. Zbog toga su adekvatan izbor prenaponske zaštite i podnosivih napona izolacije opreme ključni faktori u povećanju pouzdanosti sistema. Generalno, koordinacija izolacije se sprovodi analizom ponašanja izolacije za standardne talasne oblike udarnog i sklopnog prenapona. Međutim, prenapni koji se javljaju u pogonskim uslovima mogu značajno odstupati od standardnih talasnih oblika podnosivih napona izolacije, u pogledu vremena čela naponskog talasa, trajanja talasa, postojanja visokofrekventnih komponenti usled pojave refleksija u postrojenju i drugih faktora. U ovom radu su predstavljene moguće metode procene ponašanja izolacije opreme za realne naponske talase kojima je izolacija izložena tokom eksploatacija a koji odstupaju od standardnih talasnih oblika, analizom u frekventnom domenu. Kako u signalu prenapona postoje različite komponente na različitim frekvencijama, od kojih svaka ima različitu energiju, osnovni cilj ovog rada je analiza karakteristika izolacije jednog konkretnog transformatora sa stanovišta energetske spektralne gustine naponskog talasa koji se javlja na njegovim priključcima pri pojavi atmosferskog pražnjenja. Rezultati proračuna pokazuju da iako je amplituda prenapona niža od podnosivog napona izolacije transformatora uz odgovarajuću sigurnosnu marginu (zadovoljen uslov klasičnog pristupa koordinaciji izolacije), analiza spektra naponskog talasa u frekventnom domenu pokazuje da ipak može doći do ugrožavanja izolacije

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