The Research Of Adaptive Reclosure

In order to avoid the EHV system disaster caused by reclosing on the permanent fault of transmission line, adaptive autoreclosure based on microprocessor-based protection arises at the historic moment, but is still in the stage of theory study. This paper has proposed one new way of thought of differentiating the fault type. After observing the physical course of the single-phase grounding of transmission line, analyzing by the wavelet transformation the transient signals sampled during the fault period from the moment that single-phased grounding occurs to the moment that line breakers work, we can distinguish temporary fault from permanent one through the wave form. As far as time cost and accuracy are concerned, this criterion based on waveform discernment is superior to the traditional one based on the transmission line voltage amplitude sampled after breakers work and has been verified its exactness by dynamic emulation.