Unified Controller of Multiple Objects for Static Var Compensator
FANG Lu, LUO An, XU Xian-yong, LI Qi, FANG Hou-hui, TU Chun-ming (College of Electrical and Information Engineering, Hunan University, Changsha 410082, Hunan Province, China)
Due to the voltage fluctuation, low power factor and negative phase sequence (NPS) current caused by loads of distribution network, at where the static var compensator (SVC) was used to solve those power quality problems. A multiple objects unified controller was proposed. The proposed control method was composed of two control parts. One control branch was closed-loop control of power factor and NPS current compensation feedforward control, another control branch was closed-loop control of bus voltage at the point of common coupling (PCC) and NPS current compensation feedforward control. Two control branchs could be automatically determined by compensation objects. The fuzzy-PI controller was design for closed-loop control of power factor, and was used to coarsely adjust or finely adjust the power factor by hysteresis loop width. The optimal nonlinear PI controller was proposed for closed-loop control of PCC voltage. The control model of SVC was also established. Industrial application results not only verify the validity of the proposed control strategies and research contents, but also perform the function of reference in SVC engineering application and apparatus production.