Ground fault protection of MW distribution network

U ovom diplomskom radu objašnjene su teorijske osnove jednopolnih kvarova u elektroenergetskoj mreži. Fazorskim dijagramima prikazane su struje kvarova u distribucijskim mrežama za različite tipove mreža, odnosno različite izvedbe uzemljenja zvjezdišta transformatora. Prikazana su mjerenja kapacitivnih struja u pojedinim 35/10(20) kV trafostanicama. Provedena je analiza kvarova u distribucijskoj mreži u programskom paketu Neplan, te su dobivene minimalne struje jednopolnog, dvopolnog i tropolnog kratkog spoja po pojedinim izvodima trafostanica. Dane su predložene postavke nadstrujnih releja za 35/10(20) kV trafostanice u kojima su bila prethodno opisana provedena mjerenja kapacitivnih struja. Kao konačan ishod ovog rada uspoređivane su tablično postavke zemljospojne zaštite sa mjerenim kapacitivnim strujama kvara, te je ustanovljeno da je zaštita pravilno podešena.This paper explains the theoretical foundations of single - pole failures in the power grid. Phasor diagrams show fault currents in distribution networks for different types of networks and different grounding systems of transformer neutral point. Measurements of capacitive currents in individual 35/10 (20) kV substations are presented. An analysis of faults in the distribution network in the Neplan software was performed, and the minimum structures of single-phase, phase to phase and three-phase short circuits were obtained for individual substation. The proposed settings of overcurrent relays for 35/10 (20) kV substations are given, in which the measurements of capacitive currents are previously described. As a final result of this paper, the table settings of earth fault protection were compared with the measured capacitive fault currents, and it was found that the protection was set correctly