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Zhang, Zhengfa

Zhang, Zhengfa

PROJECT TITLE: Coordination Control of DC System and Hybrid DCCBs under DC-side Fault 

PhD period: 2018.11.01 – 2021.10.31.
Section: Electric Power Systems
Research Programme: Wind Power Systems
Supervisor: Zhe Chen
Co-Supervisors: Claus Leth Bak and Zhou Liu
Contact Information

Collaborator: To be announced later.
Funding: China Scholarship Council.


Voltage source converter (VSC) based MTDC or DC grids has been considered as one of the most suitable solutions for the integration of large-scale renewable energy. For a large high-voltage, large bulk MTDC or DC grid, in the event of a dc fault, it is desirable that the converter connected to the healthy lines continue to operate while the faulty branches are quickly isolated.  Nowadays there are mainly two categories of methods to handle this problem. One is to replace the commonly used half-bridge submodules with alternative submodules with fault-blocking abilities; the other one is to employ fault interruption devices such as DC circuit breakers (DCCBS) to isolate faulty branches. However, the first approach has the disadvantages of high on-state loss while the DCCBs will endure high current and voltage stress under DC fault in the second approach. So there raises the need for fast fault detection and location methods and coordination control of DC system and DCCBs in order to reduce the fault clearance time and reduce the requirements for fault interruption devices.

This project is mainly aiming to solve the above-mentioned problems. The main contributions of the project include analysis of system characteristics under DC fault, fast fault detection and location methods and coordination control between DC system and DCCBs. Research activities carried out in the project will help to reduce the fault clearance time and ensure the system’s normal operation even under DC-side fault. What’s more, the proposed methods will be tested in simulation software and RTDS environment to demonstrate the validity.


Publications in journals and conference papers may be found at VBN.