Analiza zemeljskostičnih tokov v zazankanem efektivno ozemljenem prenosnem omrežju

FARKAŠ, LUKA (author), Ažbe, Valentin (mentor)

Izračuni kratkostičnih okvar so eni izmed ključnih podatkov za pravilno delovanje EES. Namen izračuna je, da se zagotovi, da so sistemi varni in zanesljivi ter da se preprečijo morebitne poškodbe ali nevarnosti. V okviru diplomske naloge smo se osredotočali na izračun enofaznega in dvofaznega zemeljskega stika. Glavni cilj naloge je prikazati celoten postopek izračuna okvarnega toka, velikost toka in potek okvarnega tokokroga po obravnavanem elektroenergetskem omrežju. Na omrežju je posebnost, saj je napajalni transformator 400/110~kV vezave Yd1, kar pomeni da ni ozemljen. Ozemljitev je izvedena na primarni strani distribucijskega transformatorja 110/20~kV. Problema smo se lotili tako, da smo se najprej osredotočili na teoretični del s simetričnimi komponentami, kjer smo predstavili izpeljavo enačb napetosti in toka po metodi simetričnih komponent za dvofazni in enofazni kratek stik z dotikom zemlje. Nato smo omrežje simulirali v programskem orodju NEPLAN. Po dimenzioniranju omrežja, smo izdelali poročila po posameznih elementih, na katerih so bili podani rezultati. Iz rezultatov smo sklepali, katere impedance bodo vplivale na končni rezultat enofaznega in dvofaznega zemeljskega stika. Enofazni in dvofazni kratek stik z dotikom zemlje smo se odločili izračunati po impedančni metodi s pomočjo programskega orodja Matlab. S pomočjo slednjega smo grafično prikazali kazalčne diagrame posameznih elementov in določili potek okvarnega toka v omrežju.

• Language: Slovenian
• Keywords: okvarni tok, enofazni kratek stik z dotikom zemlje, dvofazni kratek stik z dotikom zemlje, impedančna metoda, programsko orodje NEPLAN.
• Work type: Bachelor thesis/paper
• Organization: FE - Faculty of Electrical Engineering
• Year: 2023
• PID: 20.500.12556/RUL-149345
• COBISS.SI-ID: 163627011
• Publication date in RUL: 06.09.2023

Secondary language

• Language: English
• Title: The analysis of earth-fault currents in meshed effective grounded transmission network

Abstract

Short-circuit fault calculations are one of the key inputs for the proper operation of EES. The purpose of the calculation is to ensure that the systems are safe and reliable and to prevent potential damage or hazards. Within the scope of the thesis, we focused on the calculation of single-phase and two-phase ground faults. The main objective of the thesis is to demonstrate the overall fault current calculation procedure, the magnitude of the current and the fault circuit path through the power network under consideration. There is a peculiarity on the network, because the 400/110~kV supply transformer is of the Yd1 connection, which means that it is not earthed. The earthing is carried out on the primary side of the 110/20~kV distribution transformer. The problem was approached by first focusing on the theoretical part with symmetrical components, where the derivation of the voltage and current equations by the symmetrical components method for two-phase and single-phase earth contact short-circuit was presented. The network was then simulated in the NEPLAN software tool. After the network was dimensioned, element-by-element reports were produced, on which the results were given. From the results, we deduced which impedances would affect the final result of the single-phase and two-phase ground contact. We decided to calculate the single-phase and two-phase earth contact short-circuits by the impedance method using the Matlab software tool. The latter was used to graphically display the indicative diagrams of the individual elements and to determine the fault current path in the network.

• Keywords: fault current, single pole earth fault, double pole earth fault, impedance method, NEPLAN software tool.