Open AccessHierarchical control of offshore wind farm connected by parallel diode‐rectifier‐based HVDC and HVAC links
Author(s) -
Yu Lujie,
Li Rui,
Xu Lie
Publication year - 2019
Publication title -
iet renewable power generation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.005
H-Index - 76
eISSN - 1752-1424
pISSN - 1752-1416
DOI - 10.1049/iet-rpg.2019.0033
Subject(s) - offshore wind power , rectifier (neural networks) , hvac , ac power , engineering , power control , fault (geology) , control theory (sociology) , electrical engineering , wind power , power (physics) , voltage , computer science , control (management) , physics , mechanical engineering , stochastic neural network , machine learning , air conditioning , artificial intelligence , recurrent neural network , artificial neural network , quantum mechanics , seismology , geology
This article investigates the operation of offshore wind farm connected by parallel diode‐rectifier‐based HVDC (DR‐HVDC) and HVAC links. A secondary voltage control is proposed to control the offshore AC voltage amplitude by regulating the DC voltage of the DR‐HVDC link. A secondary frequency control and a phase angle control are proposed to adjust the reactive power reference in the primary control, which synchronise the offshore point of common coupling (PCC) frequency and phase angle to those of the HVAC link. Such secondary voltage control, frequency control, and phase angle control enable seamless transition from DR‐HVDC mode to parallel mode. A tertiary power control scheme is further proposed to control the active power flow distribution between DR‐HVDC and HVAC links through the regulation of PCC phase angle. To ensure smooth transition from HVAC mode to parallel mode, a virtual DC power control is proposed to control the virtual DC power at zero prior to the connection of the DR‐HVDC link. A small‐signal model of the parallel system is developed, and the stability analysis is carried out for the proposed control scheme. Simulation results in PSCAD/EMTDC verify the proposed control under normal and fault conditions.