Pilot Protection Method Based on S Transform Energy Relative Entropy for UHVDC Line

The existing travelling wave protection for UHVDC line has low reliability under the high-resistance faults. A novel pilot protection method for UHVDC line based on S-transform energy relative entropy (STERE) has been proposed in this paper. Firstly, this paper analyzes the direction features of transient currents and voltage at the rectifier and inverter sides while internal and external faults occurred. Secondly, the STERE is used to represent the direction feature. Then the internal faults are distinguished from the external faults by using differences between STERE of both line terminals. Simulations based on PSCAD/EMTDC results indicate that the proposed protection method can recognize internal faults quickly and reliably under various fault conditions.