Naslov
Analiza stabilnosti slaboga signala visokonaponskih istosmjernih sustava s pretvaračima s naponskim ulazom
(Small-signal stability analysis of voltage source converter based high-voltage direct- current systems)

Autori
Grdenić, Goran

Vrsta, podvrsta i kategorija rada
Ocjenski radovi, doktorska disertacija

Fakultet
Fakultet elektrotehnike i računarstva

Mjesto
Zagreb

Datum
02.10

Godina
2019

Stranica
137

Mentor
Delimar, Marko

Ključne riječi
visokonaponski istosmjerni prijenos električne energije, pretvarači s naponskim ulazom, sustav pretvarača u međusobnoj električnoj blizini u izmjeničnoj mreži, analiza stabilnosti slaboga signala
(high-voltage direct-current transmission, voltage source converters, multi-infeed HVDC systems, small-signal stability analysis)

Sažetak
The main initiators of the higher employment of the voltage source converter based (VSC) high- voltage direct-current transmission (HVDC) are the connection of offshore wind power plants and the increasing necessity for flexibility and controllability in AC power grids. Transistor-based VSC technology has also facilitated the simpler implementation of truly meshed multi-terminal direct-current (MTDC) grids. Consequently, in AC grids, more converters are being located mutually in electrical proximity, forming multi-infeed HVDC (MI-HVDC) systems. Small-signal stability analysis (SSSA) is one of the most important methods for studying the inherent characteristics of dynamic systems and is a valuable tool of their design. This analysis is employed in the thesis to investigate the influence of different control and structural parameters in the aforementioned systems. In VSC-based HVDC grids, the properties of grid interaction eigenvalues with respect to the operating point and grid structure are assessed. The obtained findings have helped in the selection of a voltage controlling converter with the highest stability margin of the dominant interaction mode and for the derivation of a method to tune the coefficients for voltage droop control. In VSC-based multi- infeed systems, different voltage and reactive power regulation methods are evaluated and compared. The impact of the short-circuit ratio (SCR) at the converter's connection point, active power flow and AC line length between converters are observed. Finally, the boundary selection, between dynamically and statically modeled parts in the AC grid hybrid model, is assessed to determine the most relevant converter and AC grid parameters. The study, including the comparison procedure based on SSSA, shows the importance of the speed of the phase-locked loop, the SCR at connection point and the length of adjacent AC lines.

Izvorni jezik
Engleski

Znanstvena područja
Elektrotehnika

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