Multi-node echo method

This paper provides a new synchronization method named Multi-Node Echo Method (MNEM), which settles the problem of data/clock synchronization even with asymmetrical channels by relaying echo messages among multi-node loops. Based on MNEM, the paper further provides a method to detect symmetrical status of a communication network, a method to detect asymmetrical status of any channel in a communication network, and a method to calculate the sending and receiving delay values of any channel in a communication network, even when the channel is asymmetrical. The proposed synchronization method based on MNEM is independent of GPS, and is especially useful for line differential protection in power system. © 2011 IEEE.