The analysis and test on the Or-logic of dual-channel carrier protection for EHV transmission line

The theory and implementation scheme of an OR-logical carrier protection with optical-fiber and power line carrier dual-channel communication is analyze d in this paper, and corresponding upgrading methods for some main types of carrier protections are introduced, including: OR-logic of main protection function, remote-transmitted order and channel warning logic. Based on the principle of the fiber and carrier dual-channel pilot protection, the scheme is proposed to test on the validity of the or-logic for protection function. Utilizing the real time digital simulation system (RTDS) to simulate the fault in-lout-zone of transmission line, the OR-logic of protection can be verified overall by setting the different operating mode for the fiber and carrier pilot protection. Finally, this or-logic dual-channel carrier protection scheme is applied for a real 500kV transmission project, and the test method is conducted to verify the correctness and validity, which guarantees the project commissioning successful and system operation security.