Fault identification algorithm for MMC based hybrid High Voltage DC transmission system for deep-water oil and gas processing

This paper presents an algorithm for determining fault section on Modular Multilevel Converter (MMC) based hybrid High Voltage DC (HVDC) transmission system. The hybrid transmission system consists of an overhead line followed by a subsea cable for deep-water oil and gas processing. The algorithm is based upon independent analysis of post fault characteristic signals at each terminal. These characteristic signals are fed to the relay at the local station thus eliminating the need for communication channels between HVDC converter stations resulting in rapid fault section identification. The developed algorithm analyses characteristic signals generated at the terminal during these faults and are implemented to determine the faulty section and the fault nature (permanent or temporary).