Hybrid HVDC for Integrating Wind Farms With Special Consideration on Commutation Failure

Abstract

This version is available at https://strathprints.strath.ac.uk/53537/ Strathprints is designed to allow users to access the research output of the University of Strathclyde. Unless otherwise explicitly stated on the manuscript, Copyright © and Moral Rights for the papers on this site are retained by the individual authors and/or other copyright owners. Please check the manuscript for details of any other licences that may have been applied. You may not engage in further distribution of the material for any profitmaking activities or any commercial gain. You may freely distribute both the url (https://strathprints.strath.ac.uk/) and the content of this paper for research or private study, educational, or not-for-profit purposes without prior permission or charge.Any correspondence concerning this service should be sent to the Strathprints administrator: strathprints@strath.ac.ukThe Strathprints institutional repository (https://strathprints.strath.ac.uk) is a digital archive of University of Strathclyde research outputs. It has been developed to disseminate open access research outputs, expose data about those outputs, and enable the management and persistent access to Strathclyde's intellectual output.This paper is a post-print of a paper submitted to and accepted for publication in IEEE Transaction on Power Delivery and is subject to Institution of Electrical and Electronic Engineering Copyright. The copy of record is available at IEEE Xplore Digital Library.1  Abstract-This paper presents the control and operation of a hybrid HVDC system comprising a wind farm side VSC rectifier and a grid side LCC inverter for integrating wind power. The configuration and operation principle of the hybrid HVDC system are described. Commutation failure in the LCC inverter during an AC network disturbance is considered and its impact on the hybrid system operation is analyzed. An enhanced control strategy for the LCC inverter at the grid side and an alternative MMC topology using mixed half-bridge and full-bridge modules considered for the rectifier at the wind farm side are proposed. Simulation results using Matlab/Simulink are presented to demonstrate the robust performance during LCC inverter commutation failure to validate the operation and recovery of the hybrid system with the proposed control strategy and MMC configuration.Index Terms-Commutation failure, hybrid HVDC, LCC, MMC, VSC, wind farm. I. INTRODUCTIONLarge wind farms both onshore (e.g. in China) and offshore (e.g. in Europe) have been developed with more being planned. Many of the large wind farms are located long distance away from the load centers or the available connection points. In cost-benefit terms, HVDC is likely to be preferable to HVAC technology for the main connection of large offshore wind farms when cable lengths exceed 80-120 km. For connecting large onshore remote wind farms using overhead lines, HVDC also provides significant benefits in terms of flexible control and improved system stability, and reduced cost for transmission distance over 600...

Multi-terminal DC grids: challenges and prospects

“…As an example, recent studies propose to combine LCC-HVDC and VSC-HVDC links into hybrid systems, which leverage the most interesting advantages from both technologies [6,24,25]. Taking into account that a significant number of LCC-HVDC systems are currently in operation, VSC-HVDC stations might be added to existing LCC-HVDC systems/grids by properly coupling their DC sides to form hybrid (LCC?VSC) MTDC systems/grids [26,27].…”

A Reverse Model Predictive Control Strategy for a Modular Multilevel Converter

“…Among various multilevel converters, the modular multilevel converter (MMC) has become more popular because of its scalability, modularity, and redundancy. An MMC can be used in many high-power applications; for example, high-voltage direct current (HVDC) systems, static synchronous compensators, grid-connected systems, and medium/high voltage motor drive systems [4][5][6].…”

“…where u p is the voltage of upper arm, u n is the voltage of lower arm, U dc is the voltage of dc link, e is the voltage of grid, L o represents the arm inductance, and R and L represent the equivalent resistance and inductance of the load circuit. Based on Equations (4)- (6), the dynamic equation of the MMC can be obtained as:…”

Modeling and Analysis of an LCC HVDC System Using DC Voltage Control to Improve Transient Response and Short-Term Power Transfer Capability

“…IGH-voltage direct-current (HVDC) systems have played an important role in delivering DC power between transmission networks, mainly by exploiting the fast responses of AC/DC power converters to reference signals, e.g., reference DC power [1]. In particular, line-commutated converter-based (LCC) HVDC systems have been used in practice not only for constant DC power delivery between transmission networks but also for grid frequency control, networking with wind farms, and improved grid stability after a severe disturbance [2]- [5].…”