HVDC systems have been increasingly used in world wide. The protection which has been used in HVDC systems are travelling 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. Travelling waves of different faulty conditions are analyzed using FFT. The differences in backward travelling waves in different conditions are analyzed. These differences in backward waves were 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.
Volume 11 | Issue 5