Research On The Identification Of Lightning Faults Based On Measured Data

High voltage transmission line long distance and large span,wide distribution area,geographical and meteorological conditions are very complex,due to higher risk of lightning,lightning events occur,so lightning is one of the main reasons for high voltage transmission line power outage.If can identify the nature of the fault for lightning and the lightning fault,will take the appropriate lightning protection measures for transmission line is of great significance.We already know that lightning fault current signal of high frequency transient signal.And the high frequency signal is mainly focused on the fault current wave.Wavelet analysis,and choose the appropriate switch threshold,the mutation point to determine the fault current wave head,so that we can lock the fault wave head,selecting suitable calculation time window,reduce the amount of calculation.Because of the difference characteristic is suppress low frequency signal,highlight the high frequency signal,using the characteristics of fault current difference,so you will get the high frequency current component part of the fault current.High frequency current component part of the lightning failures can be found on the timeline area of upper and lower halves of close,rather than about lightning failures timeline fluctuation two area is obvious not equal to a,can according to this law to build a lightning fault area than criterion;After further found that the fault current difference,if the fault is struck by lightning,the difference of amplitude and difference before the amplitude is larger than than the lightning failures.Can be used in combination with this feature and area ratio criterion to judge whether the fault is lightning failures;If judgment fault is struck by lightning,we to wavelet transform of high frequency current component failure,the modulus maxima in fault current mutation point.Wavelet transform modulus maxima said mutation point polarity changes direction,intensity of modulus maxima said mutation point to the size of the transformation.According to this characteristic can be established by lightning around the strike fault and lightning counter another criterion.