Open AccessCoordinated control strategy of multi‐terminal VSC‐HVDC system considering frequency stability and power sharing
Author(s) -
Liu Yingpei,
Xie Sai,
Liang Haiping,
Cui Hanyang
Publication year - 2019
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.2018.7102
Subject(s) - electric power system , voltage source , control theory (sociology) , power (physics) , ac power , high voltage direct current , automatic frequency control , voltage , direct current , computer science , engineering , electrical engineering , control (management) , physics , quantum mechanics , artificial intelligence
Aiming at the power sharing among converter stations and the frequency stability of weak AC system connected by converter stations in multi‐terminal voltage source converter high‐voltage direct current (VSC‐HVDC) system, a coordinated control strategy without communication is proposed, which can realise the bidirectional active power support between DC system and weak AC system. The strategy divides the voltage of DC system and the frequency of weak AC system into open‐time operation area and time‐limited operation area, respectively. When DC voltage and AC frequency are in the open‐time operation area, respectively, unbalanced power in the system can be flexibly allocated according to the power margins of converter stations, which reduces DC voltage fluctuation and the influence of DC voltage errors (line length and other factors) among the converter stations on power regulation. When the AC frequency is in the time‐limited operation area, the DC system can provide power support for the weak AC system to maintain frequency stability. When the DC voltage is in the time‐limited operation area, the weak AC system loses part of the frequency quality to provide short‐term power support for the DC system to maintain the stability of VSC‐HVDC system as far as possible. The simulation results have verified the feasibility and effectiveness of the proposed control strategy.