Open AccessPowersystem dynamic voltage stability affected by open‐loop modal coupling between DFIG‐based wind farms and IM loads
Author(s) -
Su Guoyun,
Xu Long,
Du Wenjuan,
Chen Chen,
Ji Yining,
Wang Haifeng
Publication year - 2019
Publication title -
the journal of engineering
Language(s) - English
Resource type - Journals
ISSN - 2051-3305
DOI - 10.1049/joe.2018.8579
Subject(s) - control theory (sociology) , induction generator , doubly fed electric machine , coupling (piping) , modal , electric power system , voltage , wind power , modal analysis , generator (circuit theory) , loop (graph theory) , instability , power (physics) , engineering , computer science , ac power , physics , materials science , control (management) , mathematics , electrical engineering , mechanical engineering , artificial intelligence , combinatorics , polymer chemistry , structural engineering , quantum mechanics , finite element method , mechanics
Power system voltage stability can be significantly affected by load dynamic characteristics. This study examines the impacts of dynamic interaction between doubly fed induction generator (DFIG)‐based wind farms and induction motor (IM) loads on system dynamic voltage stability. It is revealed that the IM load model exhibits a recovery response which is accompanied by an IM oscillation mode (IMOM). The IMOM is first demonstrated to be closely related to system voltage stability. Moreover, a closed‐loop interconnected model is established, which consists of the following two open‐loop subsystems: DFIG; the rest of power system with IM loads. Generally, due to the fast response of the voltage‐source converter control loop, the dynamic interaction between the two open‐loop subsystems is weak. However, it is discovered that under a special condition named as open‐loop modal coupling, the aforementioned dynamic interaction will become tremendous. As a consequence, the damping of IMOM may be degraded substantially which can cause system voltage instability. Therefore, the mechanism of dynamic voltage instability issues is investigated from the perspective of modal coupling. A modified Western Systems Coordinating Council (WSCC) 9‐bus system integrated with a DFIG‐based wind farm is adopted to demonstrate and validate the above conclusions.