The current differential and travelling wave based algorithm for ultra high speed hybrid protection

Basing on the instantaneous value current differential algorithm and the current travelling wave polarity comparison algorithm, this paper proposes a novel hybrid algorithm for ultra high speed transmission line protection. The hybrid protection algorithm retains the advantages of two algorithms: fast fault detection speed and high reliability level, meanwhile, effectively eliminates their disadvantages. The hybrid relay scheme utilizes a set of hardware platform and same communication channel to perform data processing and fault detection. Simulation results coming from EMTDC demonstrate that the combined algorithm is capable of achieving fast fault detection speed while maintaining a high reliability level.