Fault mode operation strategies for dual H-bridge current flow controller in meshed HVDC grid

• Published in: Electric power systems research Vol. 160; pp. 163 - 172
• Main Authors: Mokhberdoran, Ataollah, Sau-Bassols, Joan, Prieto-Araujo, Eduardo, Gomis-Bellmunt, Oriol, Silva, Nuno, Carvalho, Adriano
• Format: Journal Article Publication
• Language: English
• Published: Amsterdam Elsevier B.V 01.07.2018; Elsevier Science Ltd
• Subjects: Circuit breakers; Component parts; Controllers; Convertidors continu-continu; Current flow controller; DC circuit breaker; DC fault currents; DC/DC converter; Electric current converters; Electric currents; Electric power transmission; Electricity distribution; Enginyeria elèctrica; Meshed DC grid; Overvoltage; Transmission lines; Àrees temàtiques de la UPC; DC fault currents; Meshed DC grid; Current flow controller; DC/DC converter; DC circuit breaker
• ISSN: 0378-7796; 1873-2046
• DOI: 10.1016/j.epsr.2018.02.002

•The behavior of interline current flow controller (CFC) during meshed HVDC grid faults is analyzed.•The CFC is found to be vulnerable against system faults even in presence of fast DC circuit breakers and fast protection schemes.•Enhanced CFC control system including a fault mode operation strategy is suggested.•Two methods of circuit level modifications to retain the CFC components during the meshed HVDC grid faults are proposed.•The performance of CFC based on the proposed methods and their functionally are validated and assessed through simulation studies. Current flow controllers (CFCs) can remove grid bottlenecks or extend grid operation area by changing amount of power flowing through DC transmission lines. This study focuses on behavior of interline H-bridge CFC in a DC grid in fault condition. In addition to the CFC circuit level fault studies, non-linear and linearized simplified models are developed for system level analysis. The analysis and fault study shows that the interline H-bridge CFC cannot survive during DC transmission line and bus faults due to an overvoltage occurring in its capacitor. Further investigation figures out that this overvoltage cannot be avoided even in presence of fast HVDC circuit breakers. Hence, an improved control system together with circuit level modifications are proposed to improve the CFC post-fault operation and to retain its components from possible damages.