Fault analysis and traveling waves based protection in bipolar 500kV HVDC system

摘要

HVDC systems have been increasingly used in world wide. The protection which has been used in HVDC systems are traveling wave based one. Traditionally used protections are based on value of line signals and time derivatives. It has been deals with many disadvantages also. They are not enough sensitive in detecting ground faults. Sometimes fails in detecting external and internal faults. The difference in backward traveling waves in different conditions is analyzed. This difference in backward waves is employed to distinguish the faulty line from healthy line. And also employed in differentiating external and internal faults in the bipolar 500 kV high voltage DC system.