Open AccessSub‐synchronous oscillations caused by the control of LCC HVDC transmission line under the condition of open‐loop modal coupling
Author(s) -
Du Wenjuan,
Zhen Zijing,
Wang Haifeng
Publication year - 2018
Publication title -
iet generation, transmission and distribution
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.92
H-Index - 110
eISSN - 1751-8695
pISSN - 1751-8687
DOI - 10.1049/iet-gtd.2018.5892
Subject(s) - control theory (sociology) , coupling (piping) , transmission line , open loop controller , electric power transmission , engineering , electric power system , loop (graph theory) , modal , transmission (telecommunications) , power (physics) , computer science , control engineering , physics , electrical engineering , control (management) , closed loop , mathematics , chemistry , mechanical engineering , artificial intelligence , combinatorics , polymer chemistry , quantum mechanics
This study examines the sub‐synchronous oscillations (SSOs) caused by the control of a line commutated converter high‐voltage, direct current (LCC HVDC) transmission line in a power system with a doubly fed induction generator for the wind power generation. The examination is based on a closed‐loop interconnected model consisted of an open‐loop HVDC subsystem and an open‐loop subsystem of power generation. The open‐loop modal coupling is the modal condition that an SSO mode of the open‐loop HVDC subsystem is close to an open‐loop SSO mode of the power generation subsystem on the complex plane. Analysis in the study indicates that under the condition of open‐loop modal coupling, the LCC HVDC line may induce strong dynamic interactions which degrade the damping of power system SSOs. An SSO index is derived to assess the degree of damping degradation of the SSOs, which can be used to identify the SSO instability risk brought about by the control of LCC HVDC transmission line. Hence, the mechanism of why the control of LCC HVDC transmission line may cause power system SSOs is revealed from the perspective of open‐loop modal coupling. Study cases are presented to demonstrate and validate the analysis and conclusions made in the study.