Open AccessSub‐synchronous oscillation in PMSGs based wind farms caused by amplification effect of GSC controller and PLL to harmonics
Author(s) -
Xu Yanhui,
Cao Yuping
Publication year - 2018
Publication title -
iet renewable power generation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.005
H-Index - 76
ISSN - 1752-1424
DOI - 10.1049/iet-rpg.2017.0740
Subject(s) - harmonics , phase locked loop , control theory (sociology) , signal (programming language) , oscillation (cell signaling) , controller (irrigation) , computer science , power (physics) , engineering , electronic engineering , physics , voltage , electrical engineering , control (management) , artificial intelligence , quantum mechanics , jitter , agronomy , biology , genetics , programming language
Sub‐synchronous oscillation (SSO) caused by direct‐drive permanent magnet synchronous generators (PMSGs) occurs frequently in Xinjiang Uygur Autonomous Region, China. As a new type of SSO, the mechanism of power oscillation triggered by PMSGs has not been clarified yet. In this study, a small‐signal analysis method was used to investigate the response process of the grid‐side converter (GSC) controller and a phase‐locked loop (PLL) to harmonics. Components with the same frequency of input disturbance signal and an output signal which generated by response process of controller superpose at the outlet of PMSGs could be amplified by positive feedback. Amplified harmonics will cause sustained power oscillation in sub‐synchronous frequency. A criterion for judging dangerous frequencies of SSO was deduced based on phase relation between input and output signals, and the form of output signal was predicted under the condition of certain parameters setting. The theoretical analysis is then validated by the simulation results and the on‐site data measured by the phasor measurement unit. Furthermore, the impacts of GSC and PLL parameters on SSO were discussed. This study provides the theoretical basis for SSO mechanism and judgement method in practical engineering.