Open AccessMethodology of calculating droop coefficients for stabilising DC voltage in VSC‐MTDC system against disturbances
Author(s) -
Zhang Fang,
Li Qingquan
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.2018.5058
Subject(s) - voltage droop , control theory (sociology) , voltage , voltage source , power (physics) , computer science , engineering , control (management) , electrical engineering , physics , artificial intelligence , quantum mechanics
The application of droop control in the voltage‐source converter‐based multi‐terminal direct current (VSC‐MTDC) system has been previously proposed in the literature. However, how to determine the droop coefficients to stabilise the DC voltage is still the key issue to concern and research. This study presents a novel calculation methodology for droop coefficients in the case of outage or power step disturbance on any converter station. The overall design objective is to minimise the DC voltage deviation between pre‐ and post‐disturbance, depicted with a quadratic programming model. In addition, the selection method of the optimal DC voltage signal for droop controllers is developed in both cases of communication failure and communication normal. Based on the calculated droop coefficients and selected DC voltage signal, the power coordinated control among the converter stations is implemented to stabilise the DC voltage of the post‐disturbance system quickly. Case studies are conducted on the Nordic 32 and New England system, respectively. The simulation results show that the proposed methodology for droop coefficients can significantly reduce the steady‐state DC voltage deviations without the limitation of preassigning the maximum allowable DC voltage deviation, compared to the methodologies existing in the literature.