Proračun prijelaznog povratnog napona na visokonaponskim SF6 prekidačima

master's thesis

• Title (english): Calculation of transient recovery voltage on high voltage SF6 circuit breakers
• Author: Božo Zečević
• Mentor: Božidar Filipović-Grčić (mentor)
• Committee member: Božidar Filipović-Grčić (predsjednik povjerenstva)
• Committee member: Viktor Milardić (član povjerenstva)
• Committee member: Goran Grdenić (član povjerenstva)
• Granter: University of Zagreb; Faculty of Electrical Engineering and Computing; Zagreb
• Defense date and country: 2022-07-13, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Electrical Engineering

Abstract

U ovom diplomskom radu proračunat je prijelazni povratni napon na prekidaču u
prijenosnoj mreži napona 220 kV. Navedeni su standardi koje trebaju zadovoljiti
prekidači smješteni na tom naponu i opisan je proces koji se odvija unutar samog
prekidača za vrijeme odvajanja njegovih kontakata. Problem je prikazan na
trofaznom modelu u programu EMTP. Provedena je simulacija i proračun za
različita mjesta i udaljenosti jednofaznog kratkog spoja od prekidača, a naglasak je
stavljen na bliski kratki spoj od udaljenosti do nekoliko kilometara jer je u praksi to
najkritičniji kvar koji zbog male impedancije i brzine kojom prenaponski val putuje
kroz mrežu za vrijeme kvara uzrokuje nastajanje povratnih napona najviših
amplituda. Ovaj problem zatim je promatran za trofazni kratki spoj i za različite
konfiguracije spojenih dalekovoda i kabela u prijenosnoj mreži. Trofazni kratki spoj
je pokazan kao prevelika zadaća za prekidač od 245 kV i preporuča se korištenje
prekidača od 300 kV za kvarove više od jedne faze. Različite lokacije kratkog
spoja su simulirane, a zatim pripadne sheme i grafovi PPN-a su prikazani slikama.
Za svaki jednofazni kratki spoj, oblik PPN-a je unutar svojih standardiziranih
krivulja što dokazuje da je prekidač sposoban isključiti kvar bez ikakvih posljedica
za sam prekidač.

Abstract (english)

In this thesis, transient recovery voltage on circuit breaker is calculated in 220 kV
transmission network. Standards which circuit breaker connected on that voltage
must satisfy are and the process which occurs inside circuit breaker during
separating it's contacts is described. The problem is showed on three phase model
in EMTP program. Simulation and calculation are done for different locations and
distances of one phase short circuit ofcircuit breaker. Accent is put on short line
fault on distance of couple kilometers because in practice it is the most critical fault
which due to low impedance and speed of overvoltage wave is spreading through
the network during fault, causes formation of transient recovery voltages with
highest amplitudes. This problem then, is observed for three phase fault and for
different configurations of connected transmission lines and cables in transmission
network. Three phase short circuit is showed up as too big task for 245 kV circuit
breaker and it is recommended to use 300 kV for more than single phase fault.
Different locations of short circuit are simulated and then associated schemes and
TRV graphs are shown on figures. For each single line fault, form of TRV is inside
its standardized envelops what proves circuit breaker is capable to switch off the
fault without any consequences for circuit breaker itself.

• Keywords: elektroenergetski sustav; prekidač; prijelazni povratni napon (PPN); EMTP; kratki spoj; prenaponi
• Keywords (english): electrical power system; circuit breaker; transient recovery voltage (TRV); EMTP; short circuit; overvoltages
• Language: croatian
• URN:NBN: urn:nbn:hr:168:148729
• Study programme: Title: Electrical Engineering and Information Technology; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra inženjer/inženjerka elektrotehnike i informacijske tehnologije (magistar/magistra inženjer/inženjerka elektrotehnike i informacijske tehnologije)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Closed access
• Created on: 2023-01-15 11:28:27