A New Protection Method for Series Compensated Transmission Line Based on the Multi direction Element Coordination

The complex fault features of series compensated line make the reliable action of protection device more difficult, then a protection scheme of series compensated transmission line based on multi directional element coordination is proposed to improve the reliability of series compensation system.In this scheme, fault type is judged by using of negative sequence current and the phase difference of current before and after fault.And the phase difference of fault voltage and fault current of negative sequence,frequency direction and fault component are used to judge whether protection device acts correctly or not when asymmetric short circuit fault,three phase short circuit fault and load fluctuation occur in system.Simulation results show that the fault location can be judged accurately by proposed protection scheme when such phenomenon as voltage reverse,current reverse,grounding with transition resistance and load fluctuation occur in system, which makes protection device trip correctly. At the same time, it has better protection performance for series compensated system due to its immunity to the influences of metal oxide varistor (MOV).