Study On Criterion For Adaptive Reclosing Of The Double Circuit Transmission Lines

The faults of transmission lines are most temporary ones in power system, in order tocommit normal work of transmission line, the reclosure technology has been widely used inelectric power system, It is an effective method to improve the stability and synchronism ofpower systems. However, the present auto-reclosure very blindness, the disability todifferentiate the permanent fault and the transient fault, reclosing on permanent fault is moreserious than that of normal short-circuit for system stability and electric equipment. In orderto avoid the harm of reclosing blindly, the type of fault should be estimated before reclosing isimplemented to realize self-adaptive reclosing.This paper focus on the application of adaptive reclosing on the EHV double circuittransmission lines, by analysis the electrical process between non-fault phase and fault phasein detail firstly, discussing coupled and influence factor of transmission lines.Secondly, aiming at transmission lines without shunt reactor, using capacitive couplingand electromagnetic coupling in the recovery voltage to differentiate the fault nature; aimingat transmission lines with shunt reactor, by studying the voltage characteristics of the faultphase in the shunt reactor and the neutral point reactor, a new criterion has been proposed todifferentiate permanent fault and transient fault.Finally, using the EMTP to simulate the different fault nature, analysis and calculatingthe dates in order to verify the criterion is effective.