Traveling-Wave-Based Lightning Fault Location Method Fault Location Method

With the development of smart grid and Ultra High Voltage Power Grid,the demands for fault location and self-healing technology have increased.Traveling-Wave-based fault location method is an ideal fault location method in modern transmission line.Improving the reliability and precision of traveling-wave-based fault location system can decrease the time of accident handing and improve the stable operation of power grid.Lightning location system can record a lot of cloud-to-ground flash,which has great significance for lightning-protection in the power system lightning and lightning fault location.The lightning location system has been promoted in the nationwide.However,due to the lightning fault information is difficult to be extracted from a large number of lightning information,the precision of fault location is low.In order to locate the lightning fault accurately,firstly,the paper analyzes the transmission characteristic of power grid lightning fault traveling wave,then do simulation with the transmission line suffered from induction lightning,fault lightning,simulation analysis,fanally a theoretical criterion for distinguishing the different lightning fault type is proposed.When the transmission line suffered from induction lightning,identification of induction lightning with the similar characteristics of its three phase transient traveling wave;When the transmission line suffered from fault lightning,identification of the relative position of the fault point and the lightning point with the different high frequency component of EMD energy spectrum which is detected by traveling wave locating device at both ends of the line.Based on identification of different lightning strike fault type,this paper puts forward the location method of calculation for different lightning strike fault types,the paper find the specific location of lightning fault point based on two terminal fault location algorithms when the transmission line suffered from lightning fault.In order to deal with the problem that traveling-wave-based double-end fault location algorithm failure when fault occurred in the double-circuit transmission lines(or multi-circuit transmission lines)or one of the traveling wave locating equipment time recorded error,a traveling-wave-based fault location method in complex transmission grid is proposed in this paper.Firstly,this paper assumes each line as fault line in turn,using the Dijkstra algorithm retained the fault line to obtain the calculating path including the fault line.If the calculating path has redundancy,the localization result could be obtained by network location algorithm directly.If the calculating path has no redundancy,an additional configuration scheme is proposed,so it can make sure the reliability when one of the traveling wave locating equipment time recorded error.Secondly,a simplified method for complex transmission lines is proposed in this paper,which can simplify the calculation procedure of network algorithm and increase the speed of the location calculation algorithm.Then the fault location results are obtained by using the network location algorithm.Simulation results show that this method is easy to implement.This method also has highly location reliability and engineering practicality,which can solve the problem of location method in complex transmission grid.In the end,this paper introduce the composition of the power grid lightning traveling wave fault location system and do experimental tests and field experiment to the system.Fault location results show that power grid lightning location system has high location accuracy,meet the requirements for power grid lightning fault location.