College of New Energy, China University of Petroleum (East China), Qingdao 266580, China
This work is supported by National Natural Science Foundation of China (No. 51777216) and Shandong Provincial Natural Science Foundation of China (No. ZR2018MEE040, No. ZR2019MEE094).
DC circuit breaker (DCCB) is a key device for clearing DC faults in voltage source converter based multi-terminal DC (VSC-MTDC) system. Most DCCB systems require to connect DC reactor in series to limit the rising rate of the fault current, but large-capacity DCCB connecting DC reactor in series could decrease the damping of DC system and reduce the stability of multi-terminal DC system. In this paper, a small-signal mathematical model for VSC-MTDC system with DC breakers is constructed and modal analysis is performed to illustrate the main factors which could affect the system stability. To solve the stability problem caused by the circuit breaker system, a damping controller based on H∞ hybrid sensitivity theory is designed to improve the weak damping characteristics of the system. Finally, with a four-terminal VSC-MTDC model implemented in MATLAB/Simulink, time-domain simulation and eigenvalue analysis results show that the proposed approach can efficiently suppress the DC system oscillations and improve the system stability. Compared with other traditional damping controllers, it is more applicable in scenarios with strong disturbances and uncertainties.
MA Wenzhong,ZHOU Guanyu,SUN Peng,et al.Design of Robust Damping Controller for VSC-MTDC System Considering DC Circuit Breaker[J].Automation of Electric Power Systems,2020,44(6):84-90.DOI:10.7500/AEPS20190411002Copy