New approach to overvoltage protection of power distribution networks

U ovoj su radnji izvršene analize novih pristupa u prenaponskoj zaštiti srednjenaponskih elektroenergetskih mreža. Analizirani su nastanci i djelovanja prenapona, te je dan pregled postojećih metoda prenaponske zaštite u srednjenaponskim distribucijskim mrežama. Kao novi pristupi u prenaponskoj zaštiti, analizirani su dugi preskočni odvodnik prenapona s antenskim modulom, te najnovija saznanja o uzrocima i zaštitnim mjerama na polju prenaponske zaštite uslijed djelovanja induciranih napona. Predstavljen je princip djelovanja LFA-AM (Long Flashover Arrester with Antenna-module) dugog preskočnog odvodnika prenapona s antenskim modulom, te izvršena analiza laboratorijskih testova. Prenaponska zaštita od pojave previsokih induciranih napona je obrađena od analize metoda proračuna induciranih napona, preko utjecaja zaštitnog vodiča na vodu i susjednih objekata na učestalost i veličinu induciranih napona, do prijedloga zaštite i usporedbe s vrijednostima dobivenima u ispitivanju na terenu. Dan je poseban osvrt na stanje prenaponske zaštite u srednjenaponskom elektroenergetskom sustavu EPHZHB.In this master thesis, a new approaches to overvoltage protection of middlevoltage power networks are carried out. Overvoltage generation and its effects are analysed and also an overview of existing methods of overvoltage protection in middle-voltage power networks is presented. As new approaches to overvoltage protection, Long Flashover Arrester with Antenna-module (LFA-AM) and the newest cognitions about causes and protection measures on the area of protection against induced voltages are analysed. Operating principle and design of Long Flashover Arrester with Antenna-module(LFA-AM) are presented and appropriate laboratory tests are performed. Overvoltage protection against induced voltages is done through: analysis of calculation methods of induced voltages, analysis of ground wire and nearby objects effect on occurrence frequency and values of induced voltages, suggestions of overvoltage protection measures and comparison of calculated results to field data. A special overview of overvoltage protection of middle-voltage power networks in EPHZHB power electricity company is given